1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Cell, Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    rc::Rc,
  43    str,
  44    sync::Arc,
  45    time::{Duration, Instant},
  46};
  47use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  48use text::{
  49    locator::Locator,
  50    subscription::{Subscription, Topic},
  51    BufferId, Edit, LineIndent, TextSummary,
  52};
  53use theme::SyntaxTheme;
  54use util::post_inc;
  55
  56const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  57
  58#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  59pub struct ExcerptId(usize);
  60
  61/// One or more [`Buffers`](Buffer) being edited in a single view.
  62///
  63/// See <https://zed.dev/features#multi-buffers>
  64pub struct MultiBuffer {
  65    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  66    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  67    snapshot: RefCell<MultiBufferSnapshot>,
  68    /// Contains the state of the buffers being edited
  69    buffers: RefCell<HashMap<BufferId, BufferState>>,
  70    // only used by consumers using `set_excerpts_for_buffer`
  71    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  72    diffs: HashMap<BufferId, DiffState>,
  73    // all_diff_hunks_expanded: bool,
  74    subscriptions: Topic,
  75    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  76    singleton: bool,
  77    history: History,
  78    title: Option<String>,
  79    capability: Capability,
  80    buffer_changed_since_sync: Rc<Cell<bool>>,
  81}
  82
  83#[derive(Clone, Debug, PartialEq, Eq)]
  84pub enum MultiOrSingleBufferOffsetRange {
  85    Single(Range<usize>),
  86    Multi(Range<usize>),
  87}
  88
  89#[derive(Clone, Debug, PartialEq, Eq)]
  90pub enum Event {
  91    ExcerptsAdded {
  92        buffer: Entity<Buffer>,
  93        predecessor: ExcerptId,
  94        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  95    },
  96    ExcerptsRemoved {
  97        ids: Vec<ExcerptId>,
  98    },
  99    ExcerptsExpanded {
 100        ids: Vec<ExcerptId>,
 101    },
 102    ExcerptsEdited {
 103        excerpt_ids: Vec<ExcerptId>,
 104        buffer_ids: Vec<BufferId>,
 105    },
 106    DiffHunksToggled,
 107    Edited {
 108        singleton_buffer_edited: bool,
 109        edited_buffer: Option<Entity<Buffer>>,
 110    },
 111    TransactionUndone {
 112        transaction_id: TransactionId,
 113    },
 114    Reloaded,
 115    ReloadNeeded,
 116
 117    LanguageChanged(BufferId),
 118    CapabilityChanged,
 119    Reparsed(BufferId),
 120    Saved,
 121    FileHandleChanged,
 122    Closed,
 123    Discarded,
 124    DirtyChanged,
 125    DiagnosticsUpdated,
 126    BufferDiffChanged,
 127}
 128
 129/// A diff hunk, representing a range of consequent lines in a multibuffer.
 130#[derive(Debug, Clone, PartialEq, Eq)]
 131pub struct MultiBufferDiffHunk {
 132    /// The row range in the multibuffer where this diff hunk appears.
 133    pub row_range: Range<MultiBufferRow>,
 134    /// The buffer ID that this hunk belongs to.
 135    pub buffer_id: BufferId,
 136    /// The range of the underlying buffer that this hunk corresponds to.
 137    pub buffer_range: Range<text::Anchor>,
 138    /// The excerpt that contains the diff hunk.
 139    pub excerpt_id: ExcerptId,
 140    /// The range within the buffer's diff base that this hunk corresponds to.
 141    pub diff_base_byte_range: Range<usize>,
 142    /// Whether or not this hunk also appears in the 'secondary diff'.
 143    pub secondary_status: DiffHunkSecondaryStatus,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (0..0)
 163            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 164    }
 165}
 166
 167#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 168pub struct PathKey {
 169    namespace: &'static str,
 170    path: Arc<Path>,
 171}
 172
 173impl PathKey {
 174    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 175        Self { namespace, path }
 176    }
 177
 178    pub fn path(&self) -> &Arc<Path> {
 179        &self.path
 180    }
 181}
 182
 183pub type MultiBufferPoint = Point;
 184type ExcerptOffset = TypedOffset<Excerpt>;
 185type ExcerptPoint = TypedPoint<Excerpt>;
 186
 187#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 188#[serde(transparent)]
 189pub struct MultiBufferRow(pub u32);
 190
 191impl MultiBufferRow {
 192    pub const MIN: Self = Self(0);
 193    pub const MAX: Self = Self(u32::MAX);
 194}
 195
 196impl std::ops::Add<usize> for MultiBufferRow {
 197    type Output = Self;
 198
 199    fn add(self, rhs: usize) -> Self::Output {
 200        MultiBufferRow(self.0 + rhs as u32)
 201    }
 202}
 203
 204#[derive(Clone)]
 205struct History {
 206    next_transaction_id: TransactionId,
 207    undo_stack: Vec<Transaction>,
 208    redo_stack: Vec<Transaction>,
 209    transaction_depth: usize,
 210    group_interval: Duration,
 211}
 212
 213#[derive(Clone)]
 214struct Transaction {
 215    id: TransactionId,
 216    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 217    first_edit_at: Instant,
 218    last_edit_at: Instant,
 219    suppress_grouping: bool,
 220}
 221
 222pub trait ToOffset: 'static + fmt::Debug {
 223    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 224}
 225
 226pub trait ToOffsetUtf16: 'static + fmt::Debug {
 227    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 228}
 229
 230pub trait ToPoint: 'static + fmt::Debug {
 231    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 232}
 233
 234pub trait ToPointUtf16: 'static + fmt::Debug {
 235    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 236}
 237
 238struct BufferState {
 239    buffer: Entity<Buffer>,
 240    last_version: clock::Global,
 241    last_non_text_state_update_count: usize,
 242    excerpts: Vec<Locator>,
 243    _subscriptions: [gpui::Subscription; 2],
 244}
 245
 246struct DiffState {
 247    diff: Entity<BufferDiff>,
 248    _subscription: gpui::Subscription,
 249}
 250
 251impl DiffState {
 252    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 253        DiffState {
 254            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 255                BufferDiffEvent::DiffChanged { changed_range } => {
 256                    if let Some(changed_range) = changed_range.clone() {
 257                        this.buffer_diff_changed(diff, changed_range, cx)
 258                    }
 259                    cx.emit(Event::BufferDiffChanged);
 260                }
 261                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 262                _ => {}
 263            }),
 264            diff,
 265        }
 266    }
 267}
 268
 269/// The contents of a [`MultiBuffer`] at a single point in time.
 270#[derive(Clone, Default)]
 271pub struct MultiBufferSnapshot {
 272    singleton: bool,
 273    excerpts: SumTree<Excerpt>,
 274    excerpt_ids: SumTree<ExcerptIdMapping>,
 275    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 276    diff_transforms: SumTree<DiffTransform>,
 277    trailing_excerpt_update_count: usize,
 278    all_diff_hunks_expanded: bool,
 279    non_text_state_update_count: usize,
 280    edit_count: usize,
 281    is_dirty: bool,
 282    has_deleted_file: bool,
 283    has_conflict: bool,
 284    show_headers: bool,
 285}
 286
 287#[derive(Debug, Clone)]
 288enum DiffTransform {
 289    BufferContent {
 290        summary: TextSummary,
 291        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 292    },
 293    DeletedHunk {
 294        summary: TextSummary,
 295        buffer_id: BufferId,
 296        hunk_info: DiffTransformHunkInfo,
 297        base_text_byte_range: Range<usize>,
 298        has_trailing_newline: bool,
 299    },
 300}
 301
 302#[derive(Clone, Copy, Debug)]
 303struct DiffTransformHunkInfo {
 304    excerpt_id: ExcerptId,
 305    hunk_start_anchor: text::Anchor,
 306    hunk_secondary_status: DiffHunkSecondaryStatus,
 307}
 308
 309impl Eq for DiffTransformHunkInfo {}
 310
 311impl PartialEq for DiffTransformHunkInfo {
 312    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 313        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 314    }
 315}
 316
 317impl std::hash::Hash for DiffTransformHunkInfo {
 318    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 319        self.excerpt_id.hash(state);
 320        self.hunk_start_anchor.hash(state);
 321    }
 322}
 323
 324#[derive(Clone)]
 325pub struct ExcerptInfo {
 326    pub id: ExcerptId,
 327    pub buffer: BufferSnapshot,
 328    pub buffer_id: BufferId,
 329    pub range: ExcerptRange<text::Anchor>,
 330    pub end_row: MultiBufferRow,
 331}
 332
 333impl std::fmt::Debug for ExcerptInfo {
 334    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 335        f.debug_struct(type_name::<Self>())
 336            .field("id", &self.id)
 337            .field("buffer_id", &self.buffer_id)
 338            .field("path", &self.buffer.file().map(|f| f.path()))
 339            .field("range", &self.range)
 340            .finish()
 341    }
 342}
 343
 344/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 345#[derive(Debug)]
 346pub struct ExcerptBoundary {
 347    pub prev: Option<ExcerptInfo>,
 348    pub next: Option<ExcerptInfo>,
 349    /// The row in the `MultiBuffer` where the boundary is located
 350    pub row: MultiBufferRow,
 351}
 352
 353impl ExcerptBoundary {
 354    pub fn starts_new_buffer(&self) -> bool {
 355        match (self.prev.as_ref(), self.next.as_ref()) {
 356            (None, _) => true,
 357            (Some(_), None) => false,
 358            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 359        }
 360    }
 361}
 362
 363#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 364pub struct RowInfo {
 365    pub buffer_id: Option<BufferId>,
 366    pub buffer_row: Option<u32>,
 367    pub multibuffer_row: Option<MultiBufferRow>,
 368    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 369}
 370
 371/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 372#[derive(Clone)]
 373struct Excerpt {
 374    /// The unique identifier for this excerpt
 375    id: ExcerptId,
 376    /// The location of the excerpt in the [`MultiBuffer`]
 377    locator: Locator,
 378    /// The buffer being excerpted
 379    buffer_id: BufferId,
 380    /// A snapshot of the buffer being excerpted
 381    buffer: BufferSnapshot,
 382    /// The range of the buffer to be shown in the excerpt
 383    range: ExcerptRange<text::Anchor>,
 384    /// The last row in the excerpted slice of the buffer
 385    max_buffer_row: BufferRow,
 386    /// A summary of the text in the excerpt
 387    text_summary: TextSummary,
 388    has_trailing_newline: bool,
 389}
 390
 391/// A public view into an `Excerpt` in a [`MultiBuffer`].
 392///
 393/// Contains methods for getting the [`Buffer`] of the excerpt,
 394/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 395#[derive(Clone)]
 396pub struct MultiBufferExcerpt<'a> {
 397    excerpt: &'a Excerpt,
 398    diff_transforms:
 399        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 400    offset: usize,
 401    excerpt_offset: ExcerptDimension<usize>,
 402    buffer_offset: usize,
 403}
 404
 405#[derive(Clone, Debug)]
 406struct ExcerptIdMapping {
 407    id: ExcerptId,
 408    locator: Locator,
 409}
 410
 411/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 412/// These ranges are relative to the buffer itself
 413#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 414pub struct ExcerptRange<T> {
 415    /// The full range of text to be shown in the excerpt.
 416    pub context: Range<T>,
 417    /// The primary range of text to be highlighted in the excerpt.
 418    /// In a multi-buffer search, this would be the text that matched the search
 419    pub primary: Option<Range<T>>,
 420}
 421
 422#[derive(Clone, Debug, Default)]
 423pub struct ExcerptSummary {
 424    excerpt_id: ExcerptId,
 425    /// The location of the last [`Excerpt`] being summarized
 426    excerpt_locator: Locator,
 427    widest_line_number: u32,
 428    text: TextSummary,
 429}
 430
 431#[derive(Debug, Clone)]
 432pub struct DiffTransformSummary {
 433    input: TextSummary,
 434    output: TextSummary,
 435}
 436
 437#[derive(Clone)]
 438pub struct MultiBufferRows<'a> {
 439    point: Point,
 440    is_empty: bool,
 441    cursor: MultiBufferCursor<'a, Point>,
 442}
 443
 444pub struct MultiBufferChunks<'a> {
 445    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 446    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 447    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 448    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 449    buffer_chunk: Option<Chunk<'a>>,
 450    range: Range<usize>,
 451    excerpt_offset_range: Range<ExcerptOffset>,
 452    excerpt_chunks: Option<ExcerptChunks<'a>>,
 453    language_aware: bool,
 454}
 455
 456pub struct ReversedMultiBufferChunks<'a> {
 457    cursor: MultiBufferCursor<'a, usize>,
 458    current_chunks: Option<rope::Chunks<'a>>,
 459    start: usize,
 460    offset: usize,
 461}
 462
 463pub struct MultiBufferBytes<'a> {
 464    range: Range<usize>,
 465    cursor: MultiBufferCursor<'a, usize>,
 466    excerpt_bytes: Option<text::Bytes<'a>>,
 467    has_trailing_newline: bool,
 468    chunk: &'a [u8],
 469}
 470
 471pub struct ReversedMultiBufferBytes<'a> {
 472    range: Range<usize>,
 473    chunks: ReversedMultiBufferChunks<'a>,
 474    chunk: &'a [u8],
 475}
 476
 477#[derive(Clone)]
 478struct MultiBufferCursor<'a, D: TextDimension> {
 479    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 480    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 481    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 482    cached_region: Option<MultiBufferRegion<'a, D>>,
 483}
 484
 485#[derive(Clone)]
 486struct MultiBufferRegion<'a, D: TextDimension> {
 487    buffer: &'a BufferSnapshot,
 488    is_main_buffer: bool,
 489    diff_hunk_status: Option<DiffHunkStatus>,
 490    excerpt: &'a Excerpt,
 491    buffer_range: Range<D>,
 492    range: Range<D>,
 493    has_trailing_newline: bool,
 494}
 495
 496struct ExcerptChunks<'a> {
 497    excerpt_id: ExcerptId,
 498    content_chunks: BufferChunks<'a>,
 499    footer_height: usize,
 500}
 501
 502#[derive(Debug)]
 503struct BufferEdit {
 504    range: Range<usize>,
 505    new_text: Arc<str>,
 506    is_insertion: bool,
 507    original_indent_column: Option<u32>,
 508    excerpt_id: ExcerptId,
 509}
 510
 511#[derive(Clone, Copy, Debug, PartialEq)]
 512enum DiffChangeKind {
 513    BufferEdited,
 514    DiffUpdated { base_changed: bool },
 515    ExpandOrCollapseHunks { expand: bool },
 516}
 517
 518#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 519pub enum ExpandExcerptDirection {
 520    Up,
 521    Down,
 522    UpAndDown,
 523}
 524
 525impl ExpandExcerptDirection {
 526    pub fn should_expand_up(&self) -> bool {
 527        match self {
 528            ExpandExcerptDirection::Up => true,
 529            ExpandExcerptDirection::Down => false,
 530            ExpandExcerptDirection::UpAndDown => true,
 531        }
 532    }
 533
 534    pub fn should_expand_down(&self) -> bool {
 535        match self {
 536            ExpandExcerptDirection::Up => false,
 537            ExpandExcerptDirection::Down => true,
 538            ExpandExcerptDirection::UpAndDown => true,
 539        }
 540    }
 541}
 542
 543#[derive(Clone, Debug, PartialEq)]
 544pub struct IndentGuide {
 545    pub buffer_id: BufferId,
 546    pub start_row: MultiBufferRow,
 547    pub end_row: MultiBufferRow,
 548    pub depth: u32,
 549    pub tab_size: u32,
 550    pub settings: IndentGuideSettings,
 551}
 552
 553impl IndentGuide {
 554    pub fn indent_level(&self) -> u32 {
 555        self.depth * self.tab_size
 556    }
 557}
 558
 559impl MultiBuffer {
 560    pub fn new(capability: Capability) -> Self {
 561        Self {
 562            snapshot: RefCell::new(MultiBufferSnapshot {
 563                show_headers: true,
 564                ..MultiBufferSnapshot::default()
 565            }),
 566            buffers: RefCell::default(),
 567            diffs: HashMap::default(),
 568            subscriptions: Topic::default(),
 569            singleton: false,
 570            capability,
 571            title: None,
 572            buffers_by_path: Default::default(),
 573            buffer_changed_since_sync: Default::default(),
 574            history: History {
 575                next_transaction_id: clock::Lamport::default(),
 576                undo_stack: Vec::new(),
 577                redo_stack: Vec::new(),
 578                transaction_depth: 0,
 579                group_interval: Duration::from_millis(300),
 580            },
 581        }
 582    }
 583
 584    pub fn without_headers(capability: Capability) -> Self {
 585        Self {
 586            snapshot: Default::default(),
 587            buffers: Default::default(),
 588            buffers_by_path: Default::default(),
 589            diffs: HashMap::default(),
 590            subscriptions: Default::default(),
 591            singleton: false,
 592            capability,
 593            buffer_changed_since_sync: Default::default(),
 594            history: History {
 595                next_transaction_id: Default::default(),
 596                undo_stack: Default::default(),
 597                redo_stack: Default::default(),
 598                transaction_depth: 0,
 599                group_interval: Duration::from_millis(300),
 600            },
 601            title: Default::default(),
 602        }
 603    }
 604
 605    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 606        let mut buffers = HashMap::default();
 607        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 608        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 609            buffer_state.buffer.update(new_cx, |buffer, _| {
 610                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 611            });
 612            buffers.insert(
 613                *buffer_id,
 614                BufferState {
 615                    buffer: buffer_state.buffer.clone(),
 616                    last_version: buffer_state.last_version.clone(),
 617                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 618                    excerpts: buffer_state.excerpts.clone(),
 619                    _subscriptions: [
 620                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 621                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 622                    ],
 623                },
 624            );
 625        }
 626        let mut diff_bases = HashMap::default();
 627        for (buffer_id, diff) in self.diffs.iter() {
 628            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 629        }
 630        Self {
 631            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 632            buffers: RefCell::new(buffers),
 633            buffers_by_path: Default::default(),
 634            diffs: diff_bases,
 635            subscriptions: Default::default(),
 636            singleton: self.singleton,
 637            capability: self.capability,
 638            history: self.history.clone(),
 639            title: self.title.clone(),
 640            buffer_changed_since_sync,
 641        }
 642    }
 643
 644    pub fn with_title(mut self, title: String) -> Self {
 645        self.title = Some(title);
 646        self
 647    }
 648
 649    pub fn read_only(&self) -> bool {
 650        self.capability == Capability::ReadOnly
 651    }
 652
 653    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 654        let mut this = Self::new(buffer.read(cx).capability());
 655        this.singleton = true;
 656        this.push_excerpts(
 657            buffer,
 658            [ExcerptRange {
 659                context: text::Anchor::MIN..text::Anchor::MAX,
 660                primary: None,
 661            }],
 662            cx,
 663        );
 664        this.snapshot.borrow_mut().singleton = true;
 665        this
 666    }
 667
 668    /// Returns an up-to-date snapshot of the MultiBuffer.
 669    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 670        self.sync(cx);
 671        self.snapshot.borrow().clone()
 672    }
 673
 674    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 675        self.sync(cx);
 676        self.snapshot.borrow()
 677    }
 678
 679    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 680        if self.singleton {
 681            return Some(
 682                self.buffers
 683                    .borrow()
 684                    .values()
 685                    .next()
 686                    .unwrap()
 687                    .buffer
 688                    .clone(),
 689            );
 690        } else {
 691            None
 692        }
 693    }
 694
 695    pub fn is_singleton(&self) -> bool {
 696        self.singleton
 697    }
 698
 699    pub fn subscribe(&mut self) -> Subscription {
 700        self.subscriptions.subscribe()
 701    }
 702
 703    pub fn is_dirty(&self, cx: &App) -> bool {
 704        self.read(cx).is_dirty()
 705    }
 706
 707    pub fn has_deleted_file(&self, cx: &App) -> bool {
 708        self.read(cx).has_deleted_file()
 709    }
 710
 711    pub fn has_conflict(&self, cx: &App) -> bool {
 712        self.read(cx).has_conflict()
 713    }
 714
 715    // The `is_empty` signature doesn't match what clippy expects
 716    #[allow(clippy::len_without_is_empty)]
 717    pub fn len(&self, cx: &App) -> usize {
 718        self.read(cx).len()
 719    }
 720
 721    pub fn is_empty(&self) -> bool {
 722        self.buffers.borrow().is_empty()
 723    }
 724
 725    pub fn symbols_containing<T: ToOffset>(
 726        &self,
 727        offset: T,
 728        theme: Option<&SyntaxTheme>,
 729        cx: &App,
 730    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 731        self.read(cx).symbols_containing(offset, theme)
 732    }
 733
 734    pub fn edit<I, S, T>(
 735        &self,
 736        edits: I,
 737        autoindent_mode: Option<AutoindentMode>,
 738        cx: &mut Context<Self>,
 739    ) where
 740        I: IntoIterator<Item = (Range<S>, T)>,
 741        S: ToOffset,
 742        T: Into<Arc<str>>,
 743    {
 744        let snapshot = self.read(cx);
 745        let edits = edits
 746            .into_iter()
 747            .map(|(range, new_text)| {
 748                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 749                if range.start > range.end {
 750                    mem::swap(&mut range.start, &mut range.end);
 751                }
 752                (range, new_text.into())
 753            })
 754            .collect::<Vec<_>>();
 755
 756        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 757
 758        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 759        fn edit_internal(
 760            this: &MultiBuffer,
 761            snapshot: Ref<MultiBufferSnapshot>,
 762            edits: Vec<(Range<usize>, Arc<str>)>,
 763            mut autoindent_mode: Option<AutoindentMode>,
 764            cx: &mut Context<MultiBuffer>,
 765        ) {
 766            if this.read_only() || this.buffers.borrow().is_empty() {
 767                return;
 768            }
 769
 770            let original_indent_columns = match &mut autoindent_mode {
 771                Some(AutoindentMode::Block {
 772                    original_indent_columns,
 773                }) => mem::take(original_indent_columns),
 774                _ => Default::default(),
 775            };
 776
 777            let (buffer_edits, edited_excerpt_ids) =
 778                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 779            drop(snapshot);
 780
 781            let mut buffer_ids = Vec::new();
 782            for (buffer_id, mut edits) in buffer_edits {
 783                buffer_ids.push(buffer_id);
 784                edits.sort_by_key(|edit| edit.range.start);
 785                this.buffers.borrow()[&buffer_id]
 786                    .buffer
 787                    .update(cx, |buffer, cx| {
 788                        let mut edits = edits.into_iter().peekable();
 789                        let mut insertions = Vec::new();
 790                        let mut original_indent_columns = Vec::new();
 791                        let mut deletions = Vec::new();
 792                        let empty_str: Arc<str> = Arc::default();
 793                        while let Some(BufferEdit {
 794                            mut range,
 795                            mut new_text,
 796                            mut is_insertion,
 797                            original_indent_column,
 798                            excerpt_id,
 799                        }) = edits.next()
 800                        {
 801                            while let Some(BufferEdit {
 802                                range: next_range,
 803                                is_insertion: next_is_insertion,
 804                                new_text: next_new_text,
 805                                excerpt_id: next_excerpt_id,
 806                                ..
 807                            }) = edits.peek()
 808                            {
 809                                if range.end >= next_range.start {
 810                                    range.end = cmp::max(next_range.end, range.end);
 811                                    is_insertion |= *next_is_insertion;
 812                                    if excerpt_id == *next_excerpt_id {
 813                                        new_text = format!("{new_text}{next_new_text}").into();
 814                                    }
 815                                    edits.next();
 816                                } else {
 817                                    break;
 818                                }
 819                            }
 820
 821                            if is_insertion {
 822                                original_indent_columns.push(original_indent_column);
 823                                insertions.push((
 824                                    buffer.anchor_before(range.start)
 825                                        ..buffer.anchor_before(range.end),
 826                                    new_text.clone(),
 827                                ));
 828                            } else if !range.is_empty() {
 829                                deletions.push((
 830                                    buffer.anchor_before(range.start)
 831                                        ..buffer.anchor_before(range.end),
 832                                    empty_str.clone(),
 833                                ));
 834                            }
 835                        }
 836
 837                        let deletion_autoindent_mode =
 838                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 839                                Some(AutoindentMode::Block {
 840                                    original_indent_columns: Default::default(),
 841                                })
 842                            } else {
 843                                autoindent_mode.clone()
 844                            };
 845                        let insertion_autoindent_mode =
 846                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 847                                Some(AutoindentMode::Block {
 848                                    original_indent_columns,
 849                                })
 850                            } else {
 851                                autoindent_mode.clone()
 852                            };
 853
 854                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 855                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 856                    })
 857            }
 858
 859            cx.emit(Event::ExcerptsEdited {
 860                excerpt_ids: edited_excerpt_ids,
 861                buffer_ids,
 862            });
 863        }
 864    }
 865
 866    fn convert_edits_to_buffer_edits(
 867        &self,
 868        edits: Vec<(Range<usize>, Arc<str>)>,
 869        snapshot: &MultiBufferSnapshot,
 870        original_indent_columns: &[Option<u32>],
 871    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 872        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 873        let mut edited_excerpt_ids = Vec::new();
 874        let mut cursor = snapshot.cursor::<usize>();
 875        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 876            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 877
 878            cursor.seek(&range.start);
 879            let mut start_region = cursor.region().expect("start offset out of bounds");
 880            if !start_region.is_main_buffer {
 881                cursor.next();
 882                if let Some(region) = cursor.region() {
 883                    start_region = region;
 884                } else {
 885                    continue;
 886                }
 887            }
 888
 889            if range.end < start_region.range.start {
 890                continue;
 891            }
 892
 893            if range.end > start_region.range.end {
 894                cursor.seek_forward(&range.end);
 895            }
 896            let mut end_region = cursor.region().expect("end offset out of bounds");
 897            if !end_region.is_main_buffer {
 898                cursor.prev();
 899                if let Some(region) = cursor.region() {
 900                    end_region = region;
 901                } else {
 902                    continue;
 903                }
 904            }
 905
 906            if range.start > end_region.range.end {
 907                continue;
 908            }
 909
 910            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 911            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 912            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 913                .min(start_region.buffer_range.end);
 914            let buffer_end =
 915                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 916
 917            if start_region.excerpt.id == end_region.excerpt.id {
 918                if start_region.is_main_buffer {
 919                    edited_excerpt_ids.push(start_region.excerpt.id);
 920                    buffer_edits
 921                        .entry(start_region.buffer.remote_id())
 922                        .or_default()
 923                        .push(BufferEdit {
 924                            range: buffer_start..buffer_end,
 925                            new_text,
 926                            is_insertion: true,
 927                            original_indent_column,
 928                            excerpt_id: start_region.excerpt.id,
 929                        });
 930                }
 931            } else {
 932                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 933                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 934                if start_region.is_main_buffer {
 935                    edited_excerpt_ids.push(start_region.excerpt.id);
 936                    buffer_edits
 937                        .entry(start_region.buffer.remote_id())
 938                        .or_default()
 939                        .push(BufferEdit {
 940                            range: start_excerpt_range,
 941                            new_text: new_text.clone(),
 942                            is_insertion: true,
 943                            original_indent_column,
 944                            excerpt_id: start_region.excerpt.id,
 945                        });
 946                }
 947                if end_region.is_main_buffer {
 948                    edited_excerpt_ids.push(end_region.excerpt.id);
 949                    buffer_edits
 950                        .entry(end_region.buffer.remote_id())
 951                        .or_default()
 952                        .push(BufferEdit {
 953                            range: end_excerpt_range,
 954                            new_text: new_text.clone(),
 955                            is_insertion: false,
 956                            original_indent_column,
 957                            excerpt_id: end_region.excerpt.id,
 958                        });
 959                }
 960
 961                cursor.seek(&range.start);
 962                cursor.next_excerpt();
 963                while let Some(region) = cursor.region() {
 964                    if region.excerpt.id == end_region.excerpt.id {
 965                        break;
 966                    }
 967                    if region.is_main_buffer {
 968                        edited_excerpt_ids.push(region.excerpt.id);
 969                        buffer_edits
 970                            .entry(region.buffer.remote_id())
 971                            .or_default()
 972                            .push(BufferEdit {
 973                                range: region.buffer_range,
 974                                new_text: new_text.clone(),
 975                                is_insertion: false,
 976                                original_indent_column,
 977                                excerpt_id: region.excerpt.id,
 978                            });
 979                    }
 980                    cursor.next_excerpt();
 981                }
 982            }
 983        }
 984        (buffer_edits, edited_excerpt_ids)
 985    }
 986
 987    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 988    where
 989        I: IntoIterator<Item = Range<S>>,
 990        S: ToOffset,
 991    {
 992        let snapshot = self.read(cx);
 993        let empty = Arc::<str>::from("");
 994        let edits = ranges
 995            .into_iter()
 996            .map(|range| {
 997                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 998                if range.start > range.end {
 999                    mem::swap(&mut range.start, &mut range.end);
1000                }
1001                (range, empty.clone())
1002            })
1003            .collect::<Vec<_>>();
1004
1005        return autoindent_ranges_internal(self, snapshot, edits, cx);
1006
1007        fn autoindent_ranges_internal(
1008            this: &MultiBuffer,
1009            snapshot: Ref<MultiBufferSnapshot>,
1010            edits: Vec<(Range<usize>, Arc<str>)>,
1011            cx: &mut Context<MultiBuffer>,
1012        ) {
1013            if this.read_only() || this.buffers.borrow().is_empty() {
1014                return;
1015            }
1016
1017            let (buffer_edits, edited_excerpt_ids) =
1018                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1019            drop(snapshot);
1020
1021            let mut buffer_ids = Vec::new();
1022            for (buffer_id, mut edits) in buffer_edits {
1023                buffer_ids.push(buffer_id);
1024                edits.sort_unstable_by_key(|edit| edit.range.start);
1025
1026                let mut ranges: Vec<Range<usize>> = Vec::new();
1027                for edit in edits {
1028                    if let Some(last_range) = ranges.last_mut() {
1029                        if edit.range.start <= last_range.end {
1030                            last_range.end = last_range.end.max(edit.range.end);
1031                            continue;
1032                        }
1033                    }
1034                    ranges.push(edit.range);
1035                }
1036
1037                this.buffers.borrow()[&buffer_id]
1038                    .buffer
1039                    .update(cx, |buffer, cx| {
1040                        buffer.autoindent_ranges(ranges, cx);
1041                    })
1042            }
1043
1044            cx.emit(Event::ExcerptsEdited {
1045                excerpt_ids: edited_excerpt_ids,
1046                buffer_ids,
1047            });
1048        }
1049    }
1050
1051    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1052    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1053    // Panics if the given position is invalid.
1054    pub fn insert_empty_line(
1055        &mut self,
1056        position: impl ToPoint,
1057        space_above: bool,
1058        space_below: bool,
1059        cx: &mut Context<Self>,
1060    ) -> Point {
1061        let multibuffer_point = position.to_point(&self.read(cx));
1062        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1063        self.start_transaction(cx);
1064        let empty_line_start = buffer.update(cx, |buffer, cx| {
1065            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1066        });
1067        self.end_transaction(cx);
1068        multibuffer_point + (empty_line_start - buffer_point)
1069    }
1070
1071    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1072        self.start_transaction_at(Instant::now(), cx)
1073    }
1074
1075    pub fn start_transaction_at(
1076        &mut self,
1077        now: Instant,
1078        cx: &mut Context<Self>,
1079    ) -> Option<TransactionId> {
1080        if let Some(buffer) = self.as_singleton() {
1081            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1082        }
1083
1084        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1085            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1086        }
1087        self.history.start_transaction(now)
1088    }
1089
1090    pub fn last_transaction_id(&self) -> Option<TransactionId> {
1091        let last_transaction = self.history.undo_stack.last()?;
1092        return Some(last_transaction.id);
1093    }
1094
1095    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1096        self.end_transaction_at(Instant::now(), cx)
1097    }
1098
1099    pub fn end_transaction_at(
1100        &mut self,
1101        now: Instant,
1102        cx: &mut Context<Self>,
1103    ) -> Option<TransactionId> {
1104        if let Some(buffer) = self.as_singleton() {
1105            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1106        }
1107
1108        let mut buffer_transactions = HashMap::default();
1109        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1110            if let Some(transaction_id) =
1111                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1112            {
1113                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1114            }
1115        }
1116
1117        if self.history.end_transaction(now, buffer_transactions) {
1118            let transaction_id = self.history.group().unwrap();
1119            Some(transaction_id)
1120        } else {
1121            None
1122        }
1123    }
1124
1125    pub fn edited_ranges_for_transaction<D>(
1126        &self,
1127        transaction_id: TransactionId,
1128        cx: &App,
1129    ) -> Vec<Range<D>>
1130    where
1131        D: TextDimension + Ord + Sub<D, Output = D>,
1132    {
1133        let Some(transaction) = self.history.transaction(transaction_id) else {
1134            return Vec::new();
1135        };
1136
1137        let mut ranges = Vec::new();
1138        let snapshot = self.read(cx);
1139        let buffers = self.buffers.borrow();
1140        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1141
1142        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1143            let Some(buffer_state) = buffers.get(buffer_id) else {
1144                continue;
1145            };
1146
1147            let buffer = buffer_state.buffer.read(cx);
1148            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1149                for excerpt_id in &buffer_state.excerpts {
1150                    cursor.seek(excerpt_id, Bias::Left, &());
1151                    if let Some(excerpt) = cursor.item() {
1152                        if excerpt.locator == *excerpt_id {
1153                            let excerpt_buffer_start =
1154                                excerpt.range.context.start.summary::<D>(buffer);
1155                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1156                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1157                            if excerpt_range.contains(&range.start)
1158                                && excerpt_range.contains(&range.end)
1159                            {
1160                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1161
1162                                let mut start = excerpt_start;
1163                                start.add_assign(&(range.start - excerpt_buffer_start));
1164                                let mut end = excerpt_start;
1165                                end.add_assign(&(range.end - excerpt_buffer_start));
1166
1167                                ranges.push(start..end);
1168                                break;
1169                            }
1170                        }
1171                    }
1172                }
1173            }
1174        }
1175
1176        ranges.sort_by_key(|range| range.start);
1177        ranges
1178    }
1179
1180    pub fn merge_transactions(
1181        &mut self,
1182        transaction: TransactionId,
1183        destination: TransactionId,
1184        cx: &mut Context<Self>,
1185    ) {
1186        if let Some(buffer) = self.as_singleton() {
1187            buffer.update(cx, |buffer, _| {
1188                buffer.merge_transactions(transaction, destination)
1189            });
1190        } else if let Some(transaction) = self.history.forget(transaction) {
1191            if let Some(destination) = self.history.transaction_mut(destination) {
1192                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1193                    if let Some(destination_buffer_transaction_id) =
1194                        destination.buffer_transactions.get(&buffer_id)
1195                    {
1196                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1197                            state.buffer.update(cx, |buffer, _| {
1198                                buffer.merge_transactions(
1199                                    buffer_transaction_id,
1200                                    *destination_buffer_transaction_id,
1201                                )
1202                            });
1203                        }
1204                    } else {
1205                        destination
1206                            .buffer_transactions
1207                            .insert(buffer_id, buffer_transaction_id);
1208                    }
1209                }
1210            }
1211        }
1212    }
1213
1214    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1215        self.history.finalize_last_transaction();
1216        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1217            buffer.update(cx, |buffer, _| {
1218                buffer.finalize_last_transaction();
1219            });
1220        }
1221    }
1222
1223    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1224    where
1225        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1226    {
1227        self.history
1228            .push_transaction(buffer_transactions, Instant::now(), cx);
1229        self.history.finalize_last_transaction();
1230    }
1231
1232    pub fn group_until_transaction(
1233        &mut self,
1234        transaction_id: TransactionId,
1235        cx: &mut Context<Self>,
1236    ) {
1237        if let Some(buffer) = self.as_singleton() {
1238            buffer.update(cx, |buffer, _| {
1239                buffer.group_until_transaction(transaction_id)
1240            });
1241        } else {
1242            self.history.group_until(transaction_id);
1243        }
1244    }
1245
1246    pub fn set_active_selections(
1247        &self,
1248        selections: &[Selection<Anchor>],
1249        line_mode: bool,
1250        cursor_shape: CursorShape,
1251        cx: &mut Context<Self>,
1252    ) {
1253        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1254            Default::default();
1255        let snapshot = self.read(cx);
1256        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1257        for selection in selections {
1258            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1259            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1260
1261            cursor.seek(&Some(start_locator), Bias::Left, &());
1262            while let Some(excerpt) = cursor.item() {
1263                if excerpt.locator > *end_locator {
1264                    break;
1265                }
1266
1267                let mut start = excerpt.range.context.start;
1268                let mut end = excerpt.range.context.end;
1269                if excerpt.id == selection.start.excerpt_id {
1270                    start = selection.start.text_anchor;
1271                }
1272                if excerpt.id == selection.end.excerpt_id {
1273                    end = selection.end.text_anchor;
1274                }
1275                selections_by_buffer
1276                    .entry(excerpt.buffer_id)
1277                    .or_default()
1278                    .push(Selection {
1279                        id: selection.id,
1280                        start,
1281                        end,
1282                        reversed: selection.reversed,
1283                        goal: selection.goal,
1284                    });
1285
1286                cursor.next(&());
1287            }
1288        }
1289
1290        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1291            if !selections_by_buffer.contains_key(buffer_id) {
1292                buffer_state
1293                    .buffer
1294                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1295            }
1296        }
1297
1298        for (buffer_id, mut selections) in selections_by_buffer {
1299            self.buffers.borrow()[&buffer_id]
1300                .buffer
1301                .update(cx, |buffer, cx| {
1302                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1303                    let mut selections = selections.into_iter().peekable();
1304                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1305                        let mut selection = selections.next()?;
1306                        while let Some(next_selection) = selections.peek() {
1307                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1308                                let next_selection = selections.next().unwrap();
1309                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1310                                    selection.end = next_selection.end;
1311                                }
1312                            } else {
1313                                break;
1314                            }
1315                        }
1316                        Some(selection)
1317                    }));
1318                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1319                });
1320        }
1321    }
1322
1323    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1324        for buffer in self.buffers.borrow().values() {
1325            buffer
1326                .buffer
1327                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1328        }
1329    }
1330
1331    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1332        let mut transaction_id = None;
1333        if let Some(buffer) = self.as_singleton() {
1334            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1335        } else {
1336            while let Some(transaction) = self.history.pop_undo() {
1337                let mut undone = false;
1338                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1339                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1340                        undone |= buffer.update(cx, |buffer, cx| {
1341                            let undo_to = *buffer_transaction_id;
1342                            if let Some(entry) = buffer.peek_undo_stack() {
1343                                *buffer_transaction_id = entry.transaction_id();
1344                            }
1345                            buffer.undo_to_transaction(undo_to, cx)
1346                        });
1347                    }
1348                }
1349
1350                if undone {
1351                    transaction_id = Some(transaction.id);
1352                    break;
1353                }
1354            }
1355        }
1356
1357        if let Some(transaction_id) = transaction_id {
1358            cx.emit(Event::TransactionUndone { transaction_id });
1359        }
1360
1361        transaction_id
1362    }
1363
1364    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1365        if let Some(buffer) = self.as_singleton() {
1366            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1367        }
1368
1369        while let Some(transaction) = self.history.pop_redo() {
1370            let mut redone = false;
1371            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1372                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1373                    redone |= buffer.update(cx, |buffer, cx| {
1374                        let redo_to = *buffer_transaction_id;
1375                        if let Some(entry) = buffer.peek_redo_stack() {
1376                            *buffer_transaction_id = entry.transaction_id();
1377                        }
1378                        buffer.redo_to_transaction(redo_to, cx)
1379                    });
1380                }
1381            }
1382
1383            if redone {
1384                return Some(transaction.id);
1385            }
1386        }
1387
1388        None
1389    }
1390
1391    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1392        if let Some(buffer) = self.as_singleton() {
1393            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1394        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1395            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1396                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1397                    buffer.update(cx, |buffer, cx| {
1398                        buffer.undo_transaction(*transaction_id, cx)
1399                    });
1400                }
1401            }
1402        }
1403    }
1404
1405    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1406        if let Some(buffer) = self.as_singleton() {
1407            buffer.update(cx, |buffer, _| {
1408                buffer.forget_transaction(transaction_id);
1409            });
1410        } else if let Some(transaction) = self.history.forget(transaction_id) {
1411            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1412                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1413                    state.buffer.update(cx, |buffer, _| {
1414                        buffer.forget_transaction(buffer_transaction_id);
1415                    });
1416                }
1417            }
1418        }
1419    }
1420
1421    pub fn push_excerpts<O>(
1422        &mut self,
1423        buffer: Entity<Buffer>,
1424        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1425        cx: &mut Context<Self>,
1426    ) -> Vec<ExcerptId>
1427    where
1428        O: text::ToOffset,
1429    {
1430        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1431    }
1432
1433    pub fn push_excerpts_with_context_lines<O>(
1434        &mut self,
1435        buffer: Entity<Buffer>,
1436        ranges: Vec<Range<O>>,
1437        context_line_count: u32,
1438        cx: &mut Context<Self>,
1439    ) -> Vec<Range<Anchor>>
1440    where
1441        O: text::ToPoint + text::ToOffset,
1442    {
1443        let buffer_id = buffer.read(cx).remote_id();
1444        let buffer_snapshot = buffer.read(cx).snapshot();
1445        let (excerpt_ranges, range_counts) =
1446            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1447
1448        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1449
1450        let mut anchor_ranges = Vec::new();
1451        let mut ranges = ranges.into_iter();
1452        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1453            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1454                let start = Anchor {
1455                    buffer_id: Some(buffer_id),
1456                    excerpt_id,
1457                    text_anchor: buffer_snapshot.anchor_after(range.start),
1458                    diff_base_anchor: None,
1459                };
1460                let end = Anchor {
1461                    buffer_id: Some(buffer_id),
1462                    excerpt_id,
1463                    text_anchor: buffer_snapshot.anchor_after(range.end),
1464                    diff_base_anchor: None,
1465                };
1466                start..end
1467            }))
1468        }
1469        anchor_ranges
1470    }
1471
1472    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1473        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1474        let snapshot = self.snapshot(cx);
1475        let excerpt = snapshot.excerpt(*excerpt_id)?;
1476        Some(Anchor::in_buffer(
1477            *excerpt_id,
1478            excerpt.buffer_id,
1479            excerpt.range.context.start,
1480        ))
1481    }
1482
1483    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1484        self.buffers_by_path.keys()
1485    }
1486
1487    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1488    pub fn set_excerpts_for_path(
1489        &mut self,
1490        path: PathKey,
1491        buffer: Entity<Buffer>,
1492        ranges: Vec<Range<Point>>,
1493        context_line_count: u32,
1494        cx: &mut Context<Self>,
1495    ) -> bool {
1496        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1497
1498        let mut insert_after = self
1499            .buffers_by_path
1500            .range(..path.clone())
1501            .next_back()
1502            .map(|(_, value)| *value.last().unwrap())
1503            .unwrap_or(ExcerptId::min());
1504        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1505
1506        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1507
1508        let mut new_iter = new.into_iter().peekable();
1509        let mut existing_iter = existing.into_iter().peekable();
1510
1511        let mut new_excerpt_ids = Vec::new();
1512        let mut to_remove = Vec::new();
1513        let mut to_insert = Vec::new();
1514        let mut added_a_new_excerpt = false;
1515        let snapshot = self.snapshot(cx);
1516
1517        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1518        excerpts_cursor.next(&());
1519
1520        loop {
1521            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1522                (Some(new), Some(existing)) => (new, existing),
1523                (None, None) => break,
1524                (None, Some(_)) => {
1525                    to_remove.push(existing_iter.next().unwrap());
1526                    continue;
1527                }
1528                (Some(_), None) => {
1529                    added_a_new_excerpt = true;
1530                    to_insert.push(new_iter.next().unwrap());
1531                    continue;
1532                }
1533            };
1534            let locator = snapshot.excerpt_locator_for_id(*existing);
1535            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1536            let existing_excerpt = excerpts_cursor.item().unwrap();
1537            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1538                to_remove.push(existing_iter.next().unwrap());
1539                to_insert.push(new_iter.next().unwrap());
1540                continue;
1541            }
1542
1543            let existing_start = existing_excerpt
1544                .range
1545                .context
1546                .start
1547                .to_point(&buffer_snapshot);
1548            let existing_end = existing_excerpt
1549                .range
1550                .context
1551                .end
1552                .to_point(&buffer_snapshot);
1553
1554            if existing_end < new.context.start {
1555                to_remove.push(existing_iter.next().unwrap());
1556                continue;
1557            } else if existing_start > new.context.end {
1558                to_insert.push(new_iter.next().unwrap());
1559                continue;
1560            }
1561
1562            // maybe merge overlapping excerpts?
1563            // it's hard to distinguish between a manually expanded excerpt, and one that
1564            // got smaller because of a missing diff.
1565            if existing_start == new.context.start && existing_end == new.context.end {
1566                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1567                    insert_after,
1568                    buffer.clone(),
1569                    mem::take(&mut to_insert),
1570                    cx,
1571                ));
1572                insert_after = existing_iter.next().unwrap();
1573                new_excerpt_ids.push(insert_after);
1574                new_iter.next();
1575            } else {
1576                to_remove.push(existing_iter.next().unwrap());
1577                to_insert.push(new_iter.next().unwrap());
1578            }
1579        }
1580
1581        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1582            insert_after,
1583            buffer,
1584            to_insert,
1585            cx,
1586        ));
1587        self.remove_excerpts(to_remove, cx);
1588        if new_excerpt_ids.is_empty() {
1589            self.buffers_by_path.remove(&path);
1590        } else {
1591            self.buffers_by_path.insert(path, new_excerpt_ids);
1592        }
1593
1594        added_a_new_excerpt
1595    }
1596
1597    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1598        self.buffers_by_path.keys().cloned()
1599    }
1600
1601    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1602        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1603            self.remove_excerpts(to_remove, cx)
1604        }
1605    }
1606
1607    pub fn push_multiple_excerpts_with_context_lines(
1608        &self,
1609        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1610        context_line_count: u32,
1611        cx: &mut Context<Self>,
1612    ) -> Task<Vec<Range<Anchor>>> {
1613        use futures::StreamExt;
1614
1615        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1616
1617        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1618
1619        for (buffer, ranges) in buffers_with_ranges {
1620            let (buffer_id, buffer_snapshot) =
1621                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1622
1623            buffer_ids.push(buffer_id);
1624
1625            cx.background_spawn({
1626                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1627
1628                async move {
1629                    let (excerpt_ranges, counts) =
1630                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1631                    excerpt_ranges_tx
1632                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1633                        .await
1634                        .ok();
1635                }
1636            })
1637            .detach()
1638        }
1639
1640        cx.spawn(move |this, mut cx| async move {
1641            let mut results_by_buffer_id = HashMap::default();
1642            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1643                excerpt_ranges_rx.next().await
1644            {
1645                results_by_buffer_id
1646                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1647            }
1648
1649            let mut multi_buffer_ranges = Vec::default();
1650            'outer: for buffer_id in buffer_ids {
1651                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1652                    results_by_buffer_id.remove(&buffer_id)
1653                else {
1654                    continue;
1655                };
1656
1657                let mut ranges = ranges.into_iter();
1658                let mut range_counts = range_counts.into_iter();
1659                for excerpt_ranges in excerpt_ranges.chunks(100) {
1660                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1661                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1662                    }) {
1663                        Ok(excerpt_ids) => excerpt_ids,
1664                        Err(_) => continue 'outer,
1665                    };
1666
1667                    for (excerpt_id, range_count) in
1668                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1669                    {
1670                        for range in ranges.by_ref().take(range_count) {
1671                            let start = Anchor {
1672                                buffer_id: Some(buffer_id),
1673                                excerpt_id,
1674                                text_anchor: range.start,
1675                                diff_base_anchor: None,
1676                            };
1677                            let end = Anchor {
1678                                buffer_id: Some(buffer_id),
1679                                excerpt_id,
1680                                text_anchor: range.end,
1681                                diff_base_anchor: None,
1682                            };
1683                            multi_buffer_ranges.push(start..end);
1684                        }
1685                    }
1686                }
1687            }
1688
1689            multi_buffer_ranges
1690        })
1691    }
1692
1693    pub fn insert_excerpts_after<O>(
1694        &mut self,
1695        prev_excerpt_id: ExcerptId,
1696        buffer: Entity<Buffer>,
1697        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1698        cx: &mut Context<Self>,
1699    ) -> Vec<ExcerptId>
1700    where
1701        O: text::ToOffset,
1702    {
1703        let mut ids = Vec::new();
1704        let mut next_excerpt_id =
1705            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1706                last_entry.id.0 + 1
1707            } else {
1708                1
1709            };
1710        self.insert_excerpts_with_ids_after(
1711            prev_excerpt_id,
1712            buffer,
1713            ranges.into_iter().map(|range| {
1714                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1715                ids.push(id);
1716                (id, range)
1717            }),
1718            cx,
1719        );
1720        ids
1721    }
1722
1723    pub fn insert_excerpts_with_ids_after<O>(
1724        &mut self,
1725        prev_excerpt_id: ExcerptId,
1726        buffer: Entity<Buffer>,
1727        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1728        cx: &mut Context<Self>,
1729    ) where
1730        O: text::ToOffset,
1731    {
1732        assert_eq!(self.history.transaction_depth, 0);
1733        let mut ranges = ranges.into_iter().peekable();
1734        if ranges.peek().is_none() {
1735            return Default::default();
1736        }
1737
1738        self.sync(cx);
1739
1740        let buffer_snapshot = buffer.read(cx).snapshot();
1741        let buffer_id = buffer_snapshot.remote_id();
1742
1743        let mut buffers = self.buffers.borrow_mut();
1744        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1745            self.buffer_changed_since_sync.replace(true);
1746            buffer.update(cx, |buffer, _| {
1747                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1748            });
1749            BufferState {
1750                last_version: buffer_snapshot.version().clone(),
1751                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1752                excerpts: Default::default(),
1753                _subscriptions: [
1754                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1755                    cx.subscribe(&buffer, Self::on_buffer_event),
1756                ],
1757                buffer: buffer.clone(),
1758            }
1759        });
1760
1761        let mut snapshot = self.snapshot.borrow_mut();
1762
1763        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1764        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1765        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1766        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1767        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1768
1769        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1770        new_excerpts.update_last(
1771            |excerpt| {
1772                excerpt.has_trailing_newline = true;
1773            },
1774            &(),
1775        );
1776
1777        let next_locator = if let Some(excerpt) = cursor.item() {
1778            excerpt.locator.clone()
1779        } else {
1780            Locator::max()
1781        };
1782
1783        let mut excerpts = Vec::new();
1784        while let Some((id, range)) = ranges.next() {
1785            let locator = Locator::between(&prev_locator, &next_locator);
1786            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1787                buffer_state.excerpts.insert(ix, locator.clone());
1788            }
1789            let range = ExcerptRange {
1790                context: buffer_snapshot.anchor_before(&range.context.start)
1791                    ..buffer_snapshot.anchor_after(&range.context.end),
1792                primary: range.primary.map(|primary| {
1793                    buffer_snapshot.anchor_before(&primary.start)
1794                        ..buffer_snapshot.anchor_after(&primary.end)
1795                }),
1796            };
1797            excerpts.push((id, range.clone()));
1798            let excerpt = Excerpt::new(
1799                id,
1800                locator.clone(),
1801                buffer_id,
1802                buffer_snapshot.clone(),
1803                range,
1804                ranges.peek().is_some() || cursor.item().is_some(),
1805            );
1806            new_excerpts.push(excerpt, &());
1807            prev_locator = locator.clone();
1808
1809            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1810                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1811            }
1812            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1813        }
1814
1815        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1816
1817        let suffix = cursor.suffix(&());
1818        let changed_trailing_excerpt = suffix.is_empty();
1819        new_excerpts.append(suffix, &());
1820        drop(cursor);
1821        snapshot.excerpts = new_excerpts;
1822        snapshot.excerpt_ids = new_excerpt_ids;
1823        if changed_trailing_excerpt {
1824            snapshot.trailing_excerpt_update_count += 1;
1825        }
1826
1827        self.sync_diff_transforms(
1828            &mut snapshot,
1829            vec![Edit {
1830                old: edit_start..edit_start,
1831                new: edit_start..edit_end,
1832            }],
1833            DiffChangeKind::BufferEdited,
1834        );
1835        cx.emit(Event::Edited {
1836            singleton_buffer_edited: false,
1837            edited_buffer: None,
1838        });
1839        cx.emit(Event::ExcerptsAdded {
1840            buffer,
1841            predecessor: prev_excerpt_id,
1842            excerpts,
1843        });
1844        cx.notify();
1845    }
1846
1847    pub fn clear(&mut self, cx: &mut Context<Self>) {
1848        self.sync(cx);
1849        let ids = self.excerpt_ids();
1850        self.buffers.borrow_mut().clear();
1851        let mut snapshot = self.snapshot.borrow_mut();
1852        let start = ExcerptOffset::new(0);
1853        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1854        snapshot.excerpts = Default::default();
1855        snapshot.trailing_excerpt_update_count += 1;
1856        snapshot.is_dirty = false;
1857        snapshot.has_deleted_file = false;
1858        snapshot.has_conflict = false;
1859
1860        self.sync_diff_transforms(
1861            &mut snapshot,
1862            vec![Edit {
1863                old: start..prev_len,
1864                new: start..start,
1865            }],
1866            DiffChangeKind::BufferEdited,
1867        );
1868        cx.emit(Event::Edited {
1869            singleton_buffer_edited: false,
1870            edited_buffer: None,
1871        });
1872        cx.emit(Event::ExcerptsRemoved { ids });
1873        cx.notify();
1874    }
1875
1876    pub fn excerpts_for_buffer(
1877        &self,
1878        buffer_id: BufferId,
1879        cx: &App,
1880    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1881        let mut excerpts = Vec::new();
1882        let snapshot = self.read(cx);
1883        let buffers = self.buffers.borrow();
1884        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1885        for locator in buffers
1886            .get(&buffer_id)
1887            .map(|state| &state.excerpts)
1888            .into_iter()
1889            .flatten()
1890        {
1891            cursor.seek_forward(&Some(locator), Bias::Left, &());
1892            if let Some(excerpt) = cursor.item() {
1893                if excerpt.locator == *locator {
1894                    excerpts.push((excerpt.id, excerpt.range.clone()));
1895                }
1896            }
1897        }
1898
1899        excerpts
1900    }
1901
1902    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1903        let snapshot = self.read(cx);
1904        let buffers = self.buffers.borrow();
1905        let mut excerpts = snapshot
1906            .excerpts
1907            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1908        let mut diff_transforms = snapshot
1909            .diff_transforms
1910            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1911        diff_transforms.next(&());
1912        let locators = buffers
1913            .get(&buffer_id)
1914            .into_iter()
1915            .flat_map(|state| &state.excerpts);
1916        let mut result = Vec::new();
1917        for locator in locators {
1918            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1919            if let Some(excerpt) = excerpts.item() {
1920                if excerpt.locator == *locator {
1921                    let excerpt_start = excerpts.start().1.clone();
1922                    let excerpt_end =
1923                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1924
1925                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1926                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1927                    let start = diff_transforms.start().1 .0 + overshoot;
1928
1929                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1930                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1931                    let end = diff_transforms.start().1 .0 + overshoot;
1932
1933                    result.push(start..end)
1934                }
1935            }
1936        }
1937        result
1938    }
1939
1940    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1941        self.snapshot
1942            .borrow()
1943            .excerpts
1944            .iter()
1945            .map(|entry| entry.buffer_id)
1946            .collect()
1947    }
1948
1949    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1950        self.snapshot
1951            .borrow()
1952            .excerpts
1953            .iter()
1954            .map(|entry| entry.id)
1955            .collect()
1956    }
1957
1958    pub fn excerpt_containing(
1959        &self,
1960        position: impl ToOffset,
1961        cx: &App,
1962    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1963        let snapshot = self.read(cx);
1964        let offset = position.to_offset(&snapshot);
1965
1966        let mut cursor = snapshot.cursor::<usize>();
1967        cursor.seek(&offset);
1968        cursor
1969            .excerpt()
1970            .or_else(|| snapshot.excerpts.last())
1971            .map(|excerpt| {
1972                (
1973                    excerpt.id,
1974                    self.buffers
1975                        .borrow()
1976                        .get(&excerpt.buffer_id)
1977                        .unwrap()
1978                        .buffer
1979                        .clone(),
1980                    excerpt.range.context.clone(),
1981                )
1982            })
1983    }
1984
1985    // If point is at the end of the buffer, the last excerpt is returned
1986    pub fn point_to_buffer_offset<T: ToOffset>(
1987        &self,
1988        point: T,
1989        cx: &App,
1990    ) -> Option<(Entity<Buffer>, usize)> {
1991        let snapshot = self.read(cx);
1992        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1993        Some((
1994            self.buffers
1995                .borrow()
1996                .get(&buffer.remote_id())?
1997                .buffer
1998                .clone(),
1999            offset,
2000        ))
2001    }
2002
2003    // If point is at the end of the buffer, the last excerpt is returned
2004    pub fn point_to_buffer_point<T: ToPoint>(
2005        &self,
2006        point: T,
2007        cx: &App,
2008    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2009        let snapshot = self.read(cx);
2010        let (buffer, point, is_main_buffer) =
2011            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2012        Some((
2013            self.buffers
2014                .borrow()
2015                .get(&buffer.remote_id())?
2016                .buffer
2017                .clone(),
2018            point,
2019            is_main_buffer,
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        self.buffer_changed_since_sync.replace(true);
2146        cx.emit(Event::Edited {
2147            singleton_buffer_edited: false,
2148            edited_buffer: None,
2149        });
2150        cx.emit(Event::ExcerptsRemoved { ids });
2151        cx.notify();
2152    }
2153
2154    pub fn wait_for_anchors<'a>(
2155        &self,
2156        anchors: impl 'a + Iterator<Item = Anchor>,
2157        cx: &mut Context<Self>,
2158    ) -> impl 'static + Future<Output = Result<()>> {
2159        let borrow = self.buffers.borrow();
2160        let mut error = None;
2161        let mut futures = Vec::new();
2162        for anchor in anchors {
2163            if let Some(buffer_id) = anchor.buffer_id {
2164                if let Some(buffer) = borrow.get(&buffer_id) {
2165                    buffer.buffer.update(cx, |buffer, _| {
2166                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2167                    });
2168                } else {
2169                    error = Some(anyhow!(
2170                        "buffer {buffer_id} is not part of this multi-buffer"
2171                    ));
2172                    break;
2173                }
2174            }
2175        }
2176        async move {
2177            if let Some(error) = error {
2178                Err(error)?;
2179            }
2180            for future in futures {
2181                future.await?;
2182            }
2183            Ok(())
2184        }
2185    }
2186
2187    pub fn text_anchor_for_position<T: ToOffset>(
2188        &self,
2189        position: T,
2190        cx: &App,
2191    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2192        let snapshot = self.read(cx);
2193        let anchor = snapshot.anchor_before(position);
2194        let buffer = self
2195            .buffers
2196            .borrow()
2197            .get(&anchor.buffer_id?)?
2198            .buffer
2199            .clone();
2200        Some((buffer, anchor.text_anchor))
2201    }
2202
2203    fn on_buffer_event(
2204        &mut self,
2205        buffer: Entity<Buffer>,
2206        event: &language::BufferEvent,
2207        cx: &mut Context<Self>,
2208    ) {
2209        cx.emit(match event {
2210            language::BufferEvent::Edited => Event::Edited {
2211                singleton_buffer_edited: true,
2212                edited_buffer: Some(buffer.clone()),
2213            },
2214            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2215            language::BufferEvent::Saved => Event::Saved,
2216            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2217            language::BufferEvent::Reloaded => Event::Reloaded,
2218            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2219            language::BufferEvent::LanguageChanged => {
2220                Event::LanguageChanged(buffer.read(cx).remote_id())
2221            }
2222            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2223            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2224            language::BufferEvent::Closed => Event::Closed,
2225            language::BufferEvent::Discarded => Event::Discarded,
2226            language::BufferEvent::CapabilityChanged => {
2227                self.capability = buffer.read(cx).capability();
2228                Event::CapabilityChanged
2229            }
2230            language::BufferEvent::Operation { .. } => return,
2231        });
2232    }
2233
2234    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2235        self.sync(cx);
2236        let mut snapshot = self.snapshot.borrow_mut();
2237        let diff = diff.read(cx);
2238        let buffer_id = diff.buffer_id;
2239        let diff = diff.snapshot(cx);
2240        snapshot.diffs.insert(buffer_id, diff);
2241    }
2242
2243    fn buffer_diff_changed(
2244        &mut self,
2245        diff: Entity<BufferDiff>,
2246        range: Range<text::Anchor>,
2247        cx: &mut Context<Self>,
2248    ) {
2249        self.sync(cx);
2250        self.buffer_changed_since_sync.replace(true);
2251
2252        let diff = diff.read(cx);
2253        let buffer_id = diff.buffer_id;
2254        let buffers = self.buffers.borrow();
2255        let Some(buffer_state) = buffers.get(&buffer_id) else {
2256            return;
2257        };
2258
2259        let buffer = buffer_state.buffer.read(cx);
2260        let diff_change_range = range.to_offset(buffer);
2261
2262        let new_diff = diff.snapshot(cx);
2263        let mut snapshot = self.snapshot.borrow_mut();
2264        let base_text_changed = snapshot
2265            .diffs
2266            .get(&buffer_id)
2267            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2268
2269        snapshot.diffs.insert(buffer_id, new_diff);
2270
2271        let mut excerpt_edits = Vec::new();
2272        for locator in &buffer_state.excerpts {
2273            let mut cursor = snapshot
2274                .excerpts
2275                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2276            cursor.seek_forward(&Some(locator), Bias::Left, &());
2277            if let Some(excerpt) = cursor.item() {
2278                if excerpt.locator == *locator {
2279                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2280                    if diff_change_range.end < excerpt_buffer_range.start
2281                        || diff_change_range.start > excerpt_buffer_range.end
2282                    {
2283                        continue;
2284                    }
2285                    let excerpt_start = cursor.start().1;
2286                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2287                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2288                        diff_change_range
2289                            .start
2290                            .saturating_sub(excerpt_buffer_range.start),
2291                    );
2292                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2293                        diff_change_range
2294                            .end
2295                            .saturating_sub(excerpt_buffer_range.start),
2296                    );
2297                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2298                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2299                    excerpt_edits.push(Edit {
2300                        old: edit_start..edit_end,
2301                        new: edit_start..edit_end,
2302                    });
2303                }
2304            }
2305        }
2306
2307        self.sync_diff_transforms(
2308            &mut snapshot,
2309            excerpt_edits,
2310            DiffChangeKind::DiffUpdated {
2311                base_changed: base_text_changed,
2312            },
2313        );
2314        cx.emit(Event::Edited {
2315            singleton_buffer_edited: false,
2316            edited_buffer: None,
2317        });
2318    }
2319
2320    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2321        self.buffers
2322            .borrow()
2323            .values()
2324            .map(|state| state.buffer.clone())
2325            .collect()
2326    }
2327
2328    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2329        self.buffers
2330            .borrow()
2331            .get(&buffer_id)
2332            .map(|state| state.buffer.clone())
2333    }
2334
2335    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2336        self.point_to_buffer_offset(point, cx)
2337            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2338    }
2339
2340    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2341        let buffer_id = self
2342            .snapshot
2343            .borrow()
2344            .excerpts
2345            .first()
2346            .map(|excerpt| excerpt.buffer.remote_id());
2347        buffer_id
2348            .and_then(|buffer_id| self.buffer(buffer_id))
2349            .map(|buffer| {
2350                let buffer = buffer.read(cx);
2351                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2352            })
2353            .unwrap_or_else(move || self.language_settings_at(0, cx))
2354    }
2355
2356    pub fn language_settings_at<'a, T: ToOffset>(
2357        &'a self,
2358        point: T,
2359        cx: &'a App,
2360    ) -> Cow<'a, LanguageSettings> {
2361        let mut language = None;
2362        let mut file = None;
2363        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2364            let buffer = buffer.read(cx);
2365            language = buffer.language_at(offset);
2366            file = buffer.file();
2367        }
2368        language_settings(language.map(|l| l.name()), file, cx)
2369    }
2370
2371    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2372        self.buffers
2373            .borrow()
2374            .values()
2375            .for_each(|state| f(&state.buffer))
2376    }
2377
2378    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2379        if let Some(title) = self.title.as_ref() {
2380            return title.into();
2381        }
2382
2383        if let Some(buffer) = self.as_singleton() {
2384            if let Some(file) = buffer.read(cx).file() {
2385                return file.file_name(cx).to_string_lossy();
2386            }
2387        }
2388
2389        "untitled".into()
2390    }
2391
2392    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2393        self.title = Some(title);
2394        cx.notify();
2395    }
2396
2397    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2398    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2399        for buffer_state in self.buffers.borrow().values() {
2400            buffer_state
2401                .buffer
2402                .update(cx, |buffer, _cx| buffer.refresh_preview());
2403        }
2404    }
2405
2406    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2407    pub fn preserve_preview(&self, cx: &App) -> bool {
2408        self.buffers
2409            .borrow()
2410            .values()
2411            .all(|state| state.buffer.read(cx).preserve_preview())
2412    }
2413
2414    #[cfg(any(test, feature = "test-support"))]
2415    pub fn is_parsing(&self, cx: &App) -> bool {
2416        self.as_singleton().unwrap().read(cx).is_parsing()
2417    }
2418
2419    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2420        let buffer_id = diff.read(cx).buffer_id;
2421        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2422        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2423    }
2424
2425    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2426        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2427    }
2428
2429    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2430        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2431    }
2432
2433    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2434        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2435    }
2436
2437    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2438        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2439        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2440    }
2441
2442    pub fn all_diff_hunks_expanded(&self) -> bool {
2443        self.snapshot.borrow().all_diff_hunks_expanded
2444    }
2445
2446    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2447        self.read(cx)
2448            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2449            .nth(1)
2450            .is_some()
2451    }
2452
2453    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2454        let snapshot = self.read(cx);
2455        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2456        let offset_range = range.to_offset(&snapshot);
2457        cursor.seek(&offset_range.start, Bias::Left, &());
2458        while let Some(item) = cursor.item() {
2459            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2460                break;
2461            }
2462            if item.hunk_info().is_some() {
2463                return true;
2464            }
2465            cursor.next(&());
2466        }
2467        false
2468    }
2469
2470    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2471        let snapshot = self.read(cx);
2472        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2473        for range in ranges {
2474            let range = range.to_point(&snapshot);
2475            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2476            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2477            let start = start.saturating_sub(1);
2478            let end = snapshot.len().min(end + 1);
2479            cursor.seek(&start, Bias::Right, &());
2480            while let Some(item) = cursor.item() {
2481                if *cursor.start() >= end {
2482                    break;
2483                }
2484                if item.hunk_info().is_some() {
2485                    return true;
2486                }
2487                cursor.next(&());
2488            }
2489        }
2490        false
2491    }
2492
2493    pub fn expand_or_collapse_diff_hunks_inner(
2494        &mut self,
2495        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2496        expand: bool,
2497        cx: &mut Context<Self>,
2498    ) {
2499        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2500            return;
2501        }
2502        self.sync(cx);
2503        let mut snapshot = self.snapshot.borrow_mut();
2504        let mut excerpt_edits = Vec::new();
2505        for (range, end_excerpt_id) in ranges {
2506            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2507                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2508                    continue;
2509                }
2510                let start = Anchor::in_buffer(
2511                    diff_hunk.excerpt_id,
2512                    diff_hunk.buffer_id,
2513                    diff_hunk.buffer_range.start,
2514                );
2515                let end = Anchor::in_buffer(
2516                    diff_hunk.excerpt_id,
2517                    diff_hunk.buffer_id,
2518                    diff_hunk.buffer_range.end,
2519                );
2520                let start = snapshot.excerpt_offset_for_anchor(&start);
2521                let end = snapshot.excerpt_offset_for_anchor(&end);
2522                excerpt_edits.push(text::Edit {
2523                    old: start..end,
2524                    new: start..end,
2525                });
2526            }
2527        }
2528
2529        self.sync_diff_transforms(
2530            &mut snapshot,
2531            excerpt_edits,
2532            DiffChangeKind::ExpandOrCollapseHunks { expand },
2533        );
2534        cx.emit(Event::DiffHunksToggled);
2535        cx.emit(Event::Edited {
2536            singleton_buffer_edited: false,
2537            edited_buffer: None,
2538        });
2539    }
2540
2541    pub fn expand_or_collapse_diff_hunks(
2542        &mut self,
2543        ranges: Vec<Range<Anchor>>,
2544        expand: bool,
2545        cx: &mut Context<Self>,
2546    ) {
2547        let snapshot = self.snapshot.borrow().clone();
2548        let ranges = ranges.iter().map(move |range| {
2549            let end_excerpt_id = range.end.excerpt_id;
2550            let range = range.to_point(&snapshot);
2551            let mut peek_end = range.end;
2552            if range.end.row < snapshot.max_row().0 {
2553                peek_end = Point::new(range.end.row + 1, 0);
2554            };
2555            (range.start..peek_end, end_excerpt_id)
2556        });
2557        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2558    }
2559
2560    pub fn resize_excerpt(
2561        &mut self,
2562        id: ExcerptId,
2563        range: Range<text::Anchor>,
2564        cx: &mut Context<Self>,
2565    ) {
2566        self.sync(cx);
2567
2568        let mut snapshot = self.snapshot.borrow_mut();
2569        let locator = snapshot.excerpt_locator_for_id(id);
2570        let mut new_excerpts = SumTree::default();
2571        let mut cursor = snapshot
2572            .excerpts
2573            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2574        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2575
2576        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2577        new_excerpts.append(prefix, &());
2578
2579        let mut excerpt = cursor.item().unwrap().clone();
2580        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2581
2582        excerpt.range.context.start = range.start;
2583        excerpt.range.context.end = range.end;
2584        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2585
2586        excerpt.text_summary = excerpt
2587            .buffer
2588            .text_summary_for_range(excerpt.range.context.clone());
2589
2590        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2591        let old_start_offset = cursor.start().1;
2592        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2593        let edit = Edit {
2594            old: old_start_offset..old_start_offset + old_text_len,
2595            new: new_start_offset..new_start_offset + new_text_len,
2596        };
2597
2598        if let Some(last_edit) = edits.last_mut() {
2599            if last_edit.old.end == edit.old.start {
2600                last_edit.old.end = edit.old.end;
2601                last_edit.new.end = edit.new.end;
2602            } else {
2603                edits.push(edit);
2604            }
2605        } else {
2606            edits.push(edit);
2607        }
2608
2609        new_excerpts.push(excerpt, &());
2610
2611        cursor.next(&());
2612
2613        new_excerpts.append(cursor.suffix(&()), &());
2614
2615        drop(cursor);
2616        snapshot.excerpts = new_excerpts;
2617
2618        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2619        cx.emit(Event::Edited {
2620            singleton_buffer_edited: false,
2621            edited_buffer: None,
2622        });
2623        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2624        cx.notify();
2625    }
2626
2627    pub fn expand_excerpts(
2628        &mut self,
2629        ids: impl IntoIterator<Item = ExcerptId>,
2630        line_count: u32,
2631        direction: ExpandExcerptDirection,
2632        cx: &mut Context<Self>,
2633    ) {
2634        if line_count == 0 {
2635            return;
2636        }
2637        self.sync(cx);
2638        let mut snapshot = self.snapshot.borrow_mut();
2639
2640        let ids = ids.into_iter().collect::<Vec<_>>();
2641        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2642        let mut new_excerpts = SumTree::default();
2643        let mut cursor = snapshot
2644            .excerpts
2645            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2646        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2647
2648        for locator in &locators {
2649            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2650            new_excerpts.append(prefix, &());
2651
2652            let mut excerpt = cursor.item().unwrap().clone();
2653            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2654
2655            let up_line_count = if direction.should_expand_up() {
2656                line_count
2657            } else {
2658                0
2659            };
2660
2661            let start_row = excerpt
2662                .range
2663                .context
2664                .start
2665                .to_point(&excerpt.buffer)
2666                .row
2667                .saturating_sub(up_line_count);
2668            let start_point = Point::new(start_row, 0);
2669            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2670
2671            let down_line_count = if direction.should_expand_down() {
2672                line_count
2673            } else {
2674                0
2675            };
2676
2677            let mut end_point = excerpt.buffer.clip_point(
2678                excerpt.range.context.end.to_point(&excerpt.buffer)
2679                    + Point::new(down_line_count, 0),
2680                Bias::Left,
2681            );
2682            end_point.column = excerpt.buffer.line_len(end_point.row);
2683            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2684            excerpt.max_buffer_row = end_point.row;
2685
2686            excerpt.text_summary = excerpt
2687                .buffer
2688                .text_summary_for_range(excerpt.range.context.clone());
2689
2690            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2691            let old_start_offset = cursor.start().1;
2692            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2693            let edit = Edit {
2694                old: old_start_offset..old_start_offset + old_text_len,
2695                new: new_start_offset..new_start_offset + new_text_len,
2696            };
2697
2698            if let Some(last_edit) = edits.last_mut() {
2699                if last_edit.old.end == edit.old.start {
2700                    last_edit.old.end = edit.old.end;
2701                    last_edit.new.end = edit.new.end;
2702                } else {
2703                    edits.push(edit);
2704                }
2705            } else {
2706                edits.push(edit);
2707            }
2708
2709            new_excerpts.push(excerpt, &());
2710
2711            cursor.next(&());
2712        }
2713
2714        new_excerpts.append(cursor.suffix(&()), &());
2715
2716        drop(cursor);
2717        snapshot.excerpts = new_excerpts;
2718
2719        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2720        cx.emit(Event::Edited {
2721            singleton_buffer_edited: false,
2722            edited_buffer: None,
2723        });
2724        cx.emit(Event::ExcerptsExpanded { ids });
2725        cx.notify();
2726    }
2727
2728    fn sync(&self, cx: &App) {
2729        let changed = self.buffer_changed_since_sync.replace(false);
2730        if !changed {
2731            return;
2732        }
2733
2734        let mut snapshot = self.snapshot.borrow_mut();
2735        let mut excerpts_to_edit = Vec::new();
2736        let mut non_text_state_updated = false;
2737        let mut is_dirty = false;
2738        let mut has_deleted_file = false;
2739        let mut has_conflict = false;
2740        let mut edited = false;
2741        let mut buffers = self.buffers.borrow_mut();
2742        for buffer_state in buffers.values_mut() {
2743            let buffer = buffer_state.buffer.read(cx);
2744            let version = buffer.version();
2745            let non_text_state_update_count = buffer.non_text_state_update_count();
2746
2747            let buffer_edited = version.changed_since(&buffer_state.last_version);
2748            let buffer_non_text_state_updated =
2749                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2750            if buffer_edited || buffer_non_text_state_updated {
2751                buffer_state.last_version = version;
2752                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2753                excerpts_to_edit.extend(
2754                    buffer_state
2755                        .excerpts
2756                        .iter()
2757                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2758                );
2759            }
2760
2761            edited |= buffer_edited;
2762            non_text_state_updated |= buffer_non_text_state_updated;
2763            is_dirty |= buffer.is_dirty();
2764            has_deleted_file |= buffer
2765                .file()
2766                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2767            has_conflict |= buffer.has_conflict();
2768        }
2769        if edited {
2770            snapshot.edit_count += 1;
2771        }
2772        if non_text_state_updated {
2773            snapshot.non_text_state_update_count += 1;
2774        }
2775        snapshot.is_dirty = is_dirty;
2776        snapshot.has_deleted_file = has_deleted_file;
2777        snapshot.has_conflict = has_conflict;
2778
2779        for (id, diff) in self.diffs.iter() {
2780            if snapshot.diffs.get(&id).is_none() {
2781                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2782            }
2783        }
2784
2785        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2786
2787        let mut edits = Vec::new();
2788        let mut new_excerpts = SumTree::default();
2789        let mut cursor = snapshot
2790            .excerpts
2791            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2792
2793        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2794            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2795            let old_excerpt = cursor.item().unwrap();
2796            let buffer = buffer.read(cx);
2797            let buffer_id = buffer.remote_id();
2798
2799            let mut new_excerpt;
2800            if buffer_edited {
2801                edits.extend(
2802                    buffer
2803                        .edits_since_in_range::<usize>(
2804                            old_excerpt.buffer.version(),
2805                            old_excerpt.range.context.clone(),
2806                        )
2807                        .map(|edit| {
2808                            let excerpt_old_start = cursor.start().1;
2809                            let excerpt_new_start =
2810                                ExcerptOffset::new(new_excerpts.summary().text.len);
2811                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2812                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2813                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2814                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2815                            Edit {
2816                                old: old_start..old_end,
2817                                new: new_start..new_end,
2818                            }
2819                        }),
2820                );
2821
2822                new_excerpt = Excerpt::new(
2823                    old_excerpt.id,
2824                    locator.clone(),
2825                    buffer_id,
2826                    buffer.snapshot(),
2827                    old_excerpt.range.clone(),
2828                    old_excerpt.has_trailing_newline,
2829                );
2830            } else {
2831                new_excerpt = old_excerpt.clone();
2832                new_excerpt.buffer = buffer.snapshot();
2833            }
2834
2835            new_excerpts.push(new_excerpt, &());
2836            cursor.next(&());
2837        }
2838        new_excerpts.append(cursor.suffix(&()), &());
2839
2840        drop(cursor);
2841        snapshot.excerpts = new_excerpts;
2842
2843        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2844    }
2845
2846    fn sync_diff_transforms(
2847        &self,
2848        snapshot: &mut MultiBufferSnapshot,
2849        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2850        change_kind: DiffChangeKind,
2851    ) {
2852        if excerpt_edits.is_empty() {
2853            return;
2854        }
2855
2856        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2857        let mut old_diff_transforms = snapshot
2858            .diff_transforms
2859            .cursor::<(ExcerptOffset, usize)>(&());
2860        let mut new_diff_transforms = SumTree::default();
2861        let mut old_expanded_hunks = HashSet::default();
2862        let mut output_edits = Vec::new();
2863        let mut output_delta = 0_isize;
2864        let mut at_transform_boundary = true;
2865        let mut end_of_current_insert = None;
2866
2867        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2868        while let Some(edit) = excerpt_edits.next() {
2869            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2870            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2871                excerpts.prev(&());
2872            }
2873
2874            // Keep any transforms that are before the edit.
2875            if at_transform_boundary {
2876                at_transform_boundary = false;
2877                let transforms_before_edit =
2878                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2879                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2880                if let Some(transform) = old_diff_transforms.item() {
2881                    if old_diff_transforms.end(&()).0 == edit.old.start
2882                        && old_diff_transforms.start().0 < edit.old.start
2883                    {
2884                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2885                        old_diff_transforms.next(&());
2886                    }
2887                }
2888            }
2889
2890            // Compute the start of the edit in output coordinates.
2891            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2892            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2893            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2894
2895            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2896                &edit,
2897                &mut excerpts,
2898                &mut old_diff_transforms,
2899                &mut new_diff_transforms,
2900                &mut end_of_current_insert,
2901                &mut old_expanded_hunks,
2902                &snapshot,
2903                change_kind,
2904            );
2905
2906            // Compute the end of the edit in output coordinates.
2907            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2908            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2909            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2910            let edit_new_end =
2911                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2912            let output_edit = Edit {
2913                old: edit_old_start..edit_old_end,
2914                new: edit_new_start..edit_new_end,
2915            };
2916
2917            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2918            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2919            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2920                output_edits.push(output_edit);
2921            }
2922
2923            // If this is the last edit that intersects the current diff transform,
2924            // then recreate the content up to the end of this transform, to prepare
2925            // for reusing additional slices of the old transforms.
2926            if excerpt_edits.peek().map_or(true, |next_edit| {
2927                next_edit.old.start >= old_diff_transforms.end(&()).0
2928            }) {
2929                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2930                    && match old_diff_transforms.item() {
2931                        Some(DiffTransform::BufferContent {
2932                            inserted_hunk_info: Some(hunk),
2933                            ..
2934                        }) => excerpts.item().is_some_and(|excerpt| {
2935                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2936                        }),
2937                        _ => true,
2938                    };
2939
2940                let mut excerpt_offset = edit.new.end;
2941                if !keep_next_old_transform {
2942                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2943                    old_diff_transforms.next(&());
2944                }
2945
2946                old_expanded_hunks.clear();
2947                self.push_buffer_content_transform(
2948                    &snapshot,
2949                    &mut new_diff_transforms,
2950                    excerpt_offset,
2951                    end_of_current_insert,
2952                );
2953                at_transform_boundary = true;
2954            }
2955        }
2956
2957        // Keep any transforms that are after the last edit.
2958        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2959
2960        // Ensure there's always at least one buffer content transform.
2961        if new_diff_transforms.is_empty() {
2962            new_diff_transforms.push(
2963                DiffTransform::BufferContent {
2964                    summary: Default::default(),
2965                    inserted_hunk_info: None,
2966                },
2967                &(),
2968            );
2969        }
2970
2971        self.subscriptions.publish(output_edits);
2972        drop(old_diff_transforms);
2973        drop(excerpts);
2974        snapshot.diff_transforms = new_diff_transforms;
2975        snapshot.edit_count += 1;
2976
2977        #[cfg(any(test, feature = "test-support"))]
2978        snapshot.check_invariants();
2979    }
2980
2981    fn recompute_diff_transforms_for_edit(
2982        &self,
2983        edit: &Edit<TypedOffset<Excerpt>>,
2984        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2985        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2986        new_diff_transforms: &mut SumTree<DiffTransform>,
2987        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2988        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2989        snapshot: &MultiBufferSnapshot,
2990        change_kind: DiffChangeKind,
2991    ) -> bool {
2992        log::trace!(
2993            "recomputing diff transform for edit {:?} => {:?}",
2994            edit.old.start.value..edit.old.end.value,
2995            edit.new.start.value..edit.new.end.value
2996        );
2997
2998        // Record which hunks were previously expanded.
2999        while let Some(item) = old_diff_transforms.item() {
3000            if let Some(hunk_info) = item.hunk_info() {
3001                log::trace!(
3002                    "previously expanded hunk at {}",
3003                    old_diff_transforms.start().0
3004                );
3005                old_expanded_hunks.insert(hunk_info);
3006            }
3007            if old_diff_transforms.end(&()).0 > edit.old.end {
3008                break;
3009            }
3010            old_diff_transforms.next(&());
3011        }
3012
3013        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3014        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3015        if old_expanded_hunks.is_empty()
3016            && change_kind == DiffChangeKind::BufferEdited
3017            && !all_diff_hunks_expanded
3018        {
3019            return false;
3020        }
3021
3022        // Visit each excerpt that intersects the edit.
3023        let mut did_expand_hunks = false;
3024        while let Some(excerpt) = excerpts.item() {
3025            // Recompute the expanded hunks in the portion of the excerpt that
3026            // intersects the edit.
3027            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3028                let buffer = &excerpt.buffer;
3029                let excerpt_start = *excerpts.start();
3030                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3031                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3032                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3033                let edit_buffer_start =
3034                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3035                let edit_buffer_end =
3036                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3037                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3038                let edit_anchor_range =
3039                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3040
3041                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3042                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3043                        continue;
3044                    }
3045
3046                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3047                    if hunk_buffer_range.start < excerpt_buffer_start {
3048                        log::trace!("skipping hunk that starts before excerpt");
3049                        continue;
3050                    }
3051
3052                    let hunk_info = DiffTransformHunkInfo {
3053                        excerpt_id: excerpt.id,
3054                        hunk_start_anchor: hunk.buffer_range.start,
3055                        hunk_secondary_status: hunk.secondary_status,
3056                    };
3057
3058                    let hunk_excerpt_start = excerpt_start
3059                        + ExcerptOffset::new(
3060                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3061                        );
3062                    let hunk_excerpt_end = excerpt_end.min(
3063                        excerpt_start
3064                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3065                    );
3066
3067                    self.push_buffer_content_transform(
3068                        snapshot,
3069                        new_diff_transforms,
3070                        hunk_excerpt_start,
3071                        *end_of_current_insert,
3072                    );
3073
3074                    // For every existing hunk, determine if it was previously expanded
3075                    // and if it should currently be expanded.
3076                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3077                    let should_expand_hunk = match &change_kind {
3078                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3079                            was_previously_expanded || all_diff_hunks_expanded
3080                        }
3081                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3082                            let intersects = hunk_buffer_range.is_empty()
3083                                || hunk_buffer_range.end > edit_buffer_start;
3084                            if *expand {
3085                                intersects || was_previously_expanded || all_diff_hunks_expanded
3086                            } else {
3087                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3088                            }
3089                        }
3090                        _ => was_previously_expanded || all_diff_hunks_expanded,
3091                    };
3092
3093                    if should_expand_hunk {
3094                        did_expand_hunks = true;
3095                        log::trace!(
3096                            "expanding hunk {:?}, excerpt:{:?}",
3097                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3098                            excerpt.id
3099                        );
3100
3101                        if !hunk.diff_base_byte_range.is_empty()
3102                            && hunk_buffer_range.start >= edit_buffer_start
3103                            && hunk_buffer_range.start <= excerpt_buffer_end
3104                        {
3105                            let base_text = diff.base_text();
3106                            let mut text_cursor =
3107                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3108                            let mut base_text_summary =
3109                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3110
3111                            let mut has_trailing_newline = false;
3112                            if base_text_summary.last_line_chars > 0 {
3113                                base_text_summary += TextSummary::newline();
3114                                has_trailing_newline = true;
3115                            }
3116
3117                            new_diff_transforms.push(
3118                                DiffTransform::DeletedHunk {
3119                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3120                                    summary: base_text_summary,
3121                                    buffer_id: excerpt.buffer_id,
3122                                    hunk_info,
3123                                    has_trailing_newline,
3124                                },
3125                                &(),
3126                            );
3127                        }
3128
3129                        if !hunk_buffer_range.is_empty() {
3130                            *end_of_current_insert =
3131                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3132                        }
3133                    }
3134                }
3135            }
3136
3137            if excerpts.end(&()) <= edit.new.end {
3138                excerpts.next(&());
3139            } else {
3140                break;
3141            }
3142        }
3143
3144        did_expand_hunks || !old_expanded_hunks.is_empty()
3145    }
3146
3147    fn append_diff_transforms(
3148        &self,
3149        new_transforms: &mut SumTree<DiffTransform>,
3150        subtree: SumTree<DiffTransform>,
3151    ) {
3152        if let Some(DiffTransform::BufferContent {
3153            inserted_hunk_info,
3154            summary,
3155        }) = subtree.first()
3156        {
3157            if self.extend_last_buffer_content_transform(
3158                new_transforms,
3159                *inserted_hunk_info,
3160                *summary,
3161            ) {
3162                let mut cursor = subtree.cursor::<()>(&());
3163                cursor.next(&());
3164                cursor.next(&());
3165                new_transforms.append(cursor.suffix(&()), &());
3166                return;
3167            }
3168        }
3169        new_transforms.append(subtree, &());
3170    }
3171
3172    fn push_diff_transform(
3173        &self,
3174        new_transforms: &mut SumTree<DiffTransform>,
3175        transform: DiffTransform,
3176    ) {
3177        if let DiffTransform::BufferContent {
3178            inserted_hunk_info: inserted_hunk_anchor,
3179            summary,
3180        } = transform
3181        {
3182            if self.extend_last_buffer_content_transform(
3183                new_transforms,
3184                inserted_hunk_anchor,
3185                summary,
3186            ) {
3187                return;
3188            }
3189        }
3190        new_transforms.push(transform, &());
3191    }
3192
3193    fn push_buffer_content_transform(
3194        &self,
3195        old_snapshot: &MultiBufferSnapshot,
3196        new_transforms: &mut SumTree<DiffTransform>,
3197        end_offset: ExcerptOffset,
3198        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3199    ) {
3200        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3201            (end_offset.min(insertion_end_offset), Some(hunk_info))
3202        });
3203        let unchanged_region = [(end_offset, None)];
3204
3205        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3206        {
3207            let start_offset = new_transforms.summary().excerpt_len();
3208            if end_offset <= start_offset {
3209                continue;
3210            }
3211            let summary_to_add = old_snapshot
3212                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3213
3214            if !self.extend_last_buffer_content_transform(
3215                new_transforms,
3216                inserted_hunk_info,
3217                summary_to_add,
3218            ) {
3219                new_transforms.push(
3220                    DiffTransform::BufferContent {
3221                        summary: summary_to_add,
3222                        inserted_hunk_info,
3223                    },
3224                    &(),
3225                )
3226            }
3227        }
3228    }
3229
3230    fn extend_last_buffer_content_transform(
3231        &self,
3232        new_transforms: &mut SumTree<DiffTransform>,
3233        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3234        summary_to_add: TextSummary,
3235    ) -> bool {
3236        let mut did_extend = false;
3237        new_transforms.update_last(
3238            |last_transform| {
3239                if let DiffTransform::BufferContent {
3240                    summary,
3241                    inserted_hunk_info: inserted_hunk_anchor,
3242                } = last_transform
3243                {
3244                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3245                        *summary += summary_to_add;
3246                        did_extend = true;
3247                    }
3248                }
3249            },
3250            &(),
3251        );
3252        did_extend
3253    }
3254}
3255
3256#[cfg(any(test, feature = "test-support"))]
3257impl MultiBuffer {
3258    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3259        let buffer = cx.new(|cx| Buffer::local(text, cx));
3260        cx.new(|cx| Self::singleton(buffer, cx))
3261    }
3262
3263    pub fn build_multi<const COUNT: usize>(
3264        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3265        cx: &mut gpui::App,
3266    ) -> Entity<Self> {
3267        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3268        for (text, ranges) in excerpts {
3269            let buffer = cx.new(|cx| Buffer::local(text, cx));
3270            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3271                context: range,
3272                primary: None,
3273            });
3274            multi.update(cx, |multi, cx| {
3275                multi.push_excerpts(buffer, excerpt_ranges, cx)
3276            });
3277        }
3278
3279        multi
3280    }
3281
3282    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3283        cx.new(|cx| Self::singleton(buffer, cx))
3284    }
3285
3286    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3287        cx.new(|cx| {
3288            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3289            let mutation_count = rng.gen_range(1..=5);
3290            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3291            multibuffer
3292        })
3293    }
3294
3295    pub fn randomly_edit(
3296        &mut self,
3297        rng: &mut impl rand::Rng,
3298        edit_count: usize,
3299        cx: &mut Context<Self>,
3300    ) {
3301        use util::RandomCharIter;
3302
3303        let snapshot = self.read(cx);
3304        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3305        let mut last_end = None;
3306        for _ in 0..edit_count {
3307            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3308                break;
3309            }
3310
3311            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3312            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3313            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3314            last_end = Some(end);
3315
3316            let mut range = start..end;
3317            if rng.gen_bool(0.2) {
3318                mem::swap(&mut range.start, &mut range.end);
3319            }
3320
3321            let new_text_len = rng.gen_range(0..10);
3322            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3323
3324            edits.push((range, new_text.into()));
3325        }
3326        log::info!("mutating multi-buffer with {:?}", edits);
3327        drop(snapshot);
3328
3329        self.edit(edits, None, cx);
3330    }
3331
3332    pub fn randomly_edit_excerpts(
3333        &mut self,
3334        rng: &mut impl rand::Rng,
3335        mutation_count: usize,
3336        cx: &mut Context<Self>,
3337    ) {
3338        use rand::prelude::*;
3339        use std::env;
3340        use util::RandomCharIter;
3341
3342        let max_excerpts = env::var("MAX_EXCERPTS")
3343            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3344            .unwrap_or(5);
3345
3346        let mut buffers = Vec::new();
3347        for _ in 0..mutation_count {
3348            if rng.gen_bool(0.05) {
3349                log::info!("Clearing multi-buffer");
3350                self.clear(cx);
3351                continue;
3352            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3353                let ids = self.excerpt_ids();
3354                let mut excerpts = HashSet::default();
3355                for _ in 0..rng.gen_range(0..ids.len()) {
3356                    excerpts.extend(ids.choose(rng).copied());
3357                }
3358
3359                let line_count = rng.gen_range(0..5);
3360
3361                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3362
3363                self.expand_excerpts(
3364                    excerpts.iter().cloned(),
3365                    line_count,
3366                    ExpandExcerptDirection::UpAndDown,
3367                    cx,
3368                );
3369                continue;
3370            }
3371
3372            let excerpt_ids = self.excerpt_ids();
3373            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3374                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3375                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3376                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3377                    let buffer = buffers.last().unwrap().read(cx);
3378                    log::info!(
3379                        "Creating new buffer {} with text: {:?}",
3380                        buffer.remote_id(),
3381                        buffer.text()
3382                    );
3383                    buffers.last().unwrap().clone()
3384                } else {
3385                    self.buffers
3386                        .borrow()
3387                        .values()
3388                        .choose(rng)
3389                        .unwrap()
3390                        .buffer
3391                        .clone()
3392                };
3393
3394                let buffer = buffer_handle.read(cx);
3395                let buffer_text = buffer.text();
3396                let ranges = (0..rng.gen_range(0..5))
3397                    .map(|_| {
3398                        let end_ix =
3399                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3400                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3401                        ExcerptRange {
3402                            context: start_ix..end_ix,
3403                            primary: None,
3404                        }
3405                    })
3406                    .collect::<Vec<_>>();
3407                log::info!(
3408                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3409                    buffer_handle.read(cx).remote_id(),
3410                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3411                    ranges
3412                        .iter()
3413                        .map(|r| &buffer_text[r.context.clone()])
3414                        .collect::<Vec<_>>()
3415                );
3416
3417                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3418                log::info!("Inserted with ids: {:?}", excerpt_id);
3419            } else {
3420                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3421                let mut excerpts_to_remove = excerpt_ids
3422                    .choose_multiple(rng, remove_count)
3423                    .cloned()
3424                    .collect::<Vec<_>>();
3425                let snapshot = self.snapshot.borrow();
3426                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3427                drop(snapshot);
3428                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3429                self.remove_excerpts(excerpts_to_remove, cx);
3430            }
3431        }
3432    }
3433
3434    pub fn randomly_mutate(
3435        &mut self,
3436        rng: &mut impl rand::Rng,
3437        mutation_count: usize,
3438        cx: &mut Context<Self>,
3439    ) {
3440        use rand::prelude::*;
3441
3442        if rng.gen_bool(0.7) || self.singleton {
3443            let buffer = self
3444                .buffers
3445                .borrow()
3446                .values()
3447                .choose(rng)
3448                .map(|state| state.buffer.clone());
3449
3450            if let Some(buffer) = buffer {
3451                buffer.update(cx, |buffer, cx| {
3452                    if rng.gen() {
3453                        buffer.randomly_edit(rng, mutation_count, cx);
3454                    } else {
3455                        buffer.randomly_undo_redo(rng, cx);
3456                    }
3457                });
3458            } else {
3459                self.randomly_edit(rng, mutation_count, cx);
3460            }
3461        } else {
3462            self.randomly_edit_excerpts(rng, mutation_count, cx);
3463        }
3464
3465        self.check_invariants(cx);
3466    }
3467
3468    fn check_invariants(&self, cx: &App) {
3469        self.read(cx).check_invariants();
3470    }
3471}
3472
3473impl EventEmitter<Event> for MultiBuffer {}
3474
3475impl MultiBufferSnapshot {
3476    pub fn text(&self) -> String {
3477        self.chunks(0..self.len(), false)
3478            .map(|chunk| chunk.text)
3479            .collect()
3480    }
3481
3482    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3483        self.reversed_chunks_in_range(0..position.to_offset(self))
3484            .flat_map(|c| c.chars().rev())
3485    }
3486
3487    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3488        let mut cursor = self.cursor::<usize>();
3489        cursor.seek(&range.end);
3490        let current_chunks = cursor.region().as_ref().map(|region| {
3491            let start_overshoot = range.start.saturating_sub(region.range.start);
3492            let end_overshoot = range.end - region.range.start;
3493            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3494            let start = region.buffer_range.start + start_overshoot;
3495            region.buffer.reversed_chunks_in_range(start..end)
3496        });
3497        ReversedMultiBufferChunks {
3498            cursor,
3499            current_chunks,
3500            start: range.start,
3501            offset: range.end,
3502        }
3503    }
3504
3505    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3506        let offset = position.to_offset(self);
3507        self.text_for_range(offset..self.len())
3508            .flat_map(|chunk| chunk.chars())
3509    }
3510
3511    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3512        self.chunks(range, false).map(|chunk| chunk.text)
3513    }
3514
3515    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3516        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3517            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3518    }
3519
3520    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3521    where
3522        T: ToOffset,
3523    {
3524        let position = position.to_offset(self);
3525        position == self.clip_offset(position, Bias::Left)
3526            && self
3527                .bytes_in_range(position..self.len())
3528                .flatten()
3529                .copied()
3530                .take(needle.len())
3531                .eq(needle.bytes())
3532    }
3533
3534    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3535        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3536    }
3537
3538    pub fn diff_hunks_in_range<T: ToPoint>(
3539        &self,
3540        range: Range<T>,
3541    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3542        let query_range = range.start.to_point(self)..range.end.to_point(self);
3543        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3544            let diff = self.diffs.get(&buffer.remote_id())?;
3545            let buffer_start = buffer.anchor_before(buffer_range.start);
3546            let buffer_end = buffer.anchor_after(buffer_range.end);
3547            Some(
3548                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3549                    .filter_map(|hunk| {
3550                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3551                            return None;
3552                        }
3553                        Some((hunk.range.clone(), hunk))
3554                    }),
3555            )
3556        })
3557        .filter_map(move |(range, hunk, excerpt)| {
3558            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3559            {
3560                return None;
3561            }
3562            let end_row = if range.end.column == 0 {
3563                range.end.row
3564            } else {
3565                range.end.row + 1
3566            };
3567            Some(MultiBufferDiffHunk {
3568                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3569                buffer_id: excerpt.buffer_id,
3570                excerpt_id: excerpt.id,
3571                buffer_range: hunk.buffer_range.clone(),
3572                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3573                secondary_status: hunk.secondary_status,
3574            })
3575        })
3576    }
3577
3578    pub fn excerpt_ids_for_range<T: ToOffset>(
3579        &self,
3580        range: Range<T>,
3581    ) -> impl Iterator<Item = ExcerptId> + '_ {
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                return None;
3589            }
3590            cursor.next_excerpt();
3591            Some(region.excerpt.id)
3592        })
3593    }
3594
3595    pub fn buffer_ids_for_range<T: ToOffset>(
3596        &self,
3597        range: Range<T>,
3598    ) -> impl Iterator<Item = BufferId> + '_ {
3599        let range = range.start.to_offset(self)..range.end.to_offset(self);
3600        let mut cursor = self.cursor::<usize>();
3601        cursor.seek(&range.start);
3602        std::iter::from_fn(move || {
3603            let region = cursor.region()?;
3604            if region.range.start > range.end
3605                || region.range.start == range.end && region.range.start > range.start
3606            {
3607                return None;
3608            }
3609            cursor.next_excerpt();
3610            Some(region.excerpt.buffer_id)
3611        })
3612    }
3613
3614    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3615        &self,
3616        ranges: impl Iterator<Item = Range<T>>,
3617    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3618        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3619    }
3620
3621    pub fn range_to_buffer_ranges<T: ToOffset>(
3622        &self,
3623        range: Range<T>,
3624    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3625        let start = range.start.to_offset(&self);
3626        let end = range.end.to_offset(&self);
3627
3628        let mut cursor = self.cursor::<usize>();
3629        cursor.seek(&start);
3630
3631        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3632        while let Some(region) = cursor.region() {
3633            if region.range.start > end {
3634                break;
3635            }
3636            if region.is_main_buffer {
3637                let start_overshoot = start.saturating_sub(region.range.start);
3638                let end_overshoot = end.saturating_sub(region.range.start);
3639                let start = region
3640                    .buffer_range
3641                    .end
3642                    .min(region.buffer_range.start + start_overshoot);
3643                let end = region
3644                    .buffer_range
3645                    .end
3646                    .min(region.buffer_range.start + end_overshoot);
3647                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3648                    *excerpt_id == region.excerpt.id && prev_range.end == start
3649                }) {
3650                    prev.1.end = end;
3651                } else {
3652                    result.push((region.buffer, start..end, region.excerpt.id));
3653                }
3654            }
3655            cursor.next();
3656        }
3657        result
3658    }
3659
3660    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3661        &self,
3662        range: Range<T>,
3663    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3664        let start = range.start.to_offset(&self);
3665        let end = range.end.to_offset(&self);
3666
3667        let mut cursor = self.cursor::<usize>();
3668        cursor.seek(&start);
3669
3670        std::iter::from_fn(move || {
3671            let region = cursor.region()?;
3672            if region.range.start > end {
3673                return None;
3674            }
3675            let start_overshoot = start.saturating_sub(region.range.start);
3676            let end_overshoot = end.saturating_sub(region.range.start);
3677            let start = region
3678                .buffer_range
3679                .end
3680                .min(region.buffer_range.start + start_overshoot);
3681            let end = region
3682                .buffer_range
3683                .end
3684                .min(region.buffer_range.start + end_overshoot);
3685
3686            let region_excerpt_id = region.excerpt.id;
3687            let deleted_hunk_anchor = if region.is_main_buffer {
3688                None
3689            } else {
3690                Some(self.anchor_before(region.range.start))
3691            };
3692            let result = (
3693                region.buffer,
3694                start..end,
3695                region_excerpt_id,
3696                deleted_hunk_anchor,
3697            );
3698            cursor.next();
3699            Some(result)
3700        })
3701    }
3702
3703    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3704    /// coordinates.
3705    ///
3706    /// The given callback will be called for every excerpt intersecting the given range. It will
3707    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3708    /// The callback should return an iterator of metadata items from that buffer, each paired
3709    /// with a buffer range.
3710    ///
3711    /// The returned iterator yields each of these metadata items, paired with its range in
3712    /// multi-buffer coordinates.
3713    fn lift_buffer_metadata<'a, D, M, I>(
3714        &'a self,
3715        query_range: Range<D>,
3716        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3717    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3718    where
3719        I: Iterator<Item = (Range<D>, M)> + 'a,
3720        D: TextDimension + Ord + Sub<D, Output = D>,
3721    {
3722        let max_position = D::from_text_summary(&self.text_summary());
3723        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3724        let mut cursor = self.cursor::<D>();
3725
3726        // Find the excerpt and buffer offset where the given range ends.
3727        cursor.seek(&query_range.end);
3728        let mut range_end = None;
3729        while let Some(region) = cursor.region() {
3730            if region.is_main_buffer {
3731                let mut buffer_end = region.buffer_range.start;
3732                let overshoot = if query_range.end > region.range.start {
3733                    query_range.end - region.range.start
3734                } else {
3735                    D::default()
3736                };
3737                buffer_end.add_assign(&overshoot);
3738                range_end = Some((region.excerpt.id, buffer_end));
3739                break;
3740            }
3741            cursor.next();
3742        }
3743
3744        cursor.seek(&query_range.start);
3745
3746        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3747            if region.range.start > D::zero(&()) {
3748                cursor.prev()
3749            }
3750        }
3751
3752        iter::from_fn(move || loop {
3753            let excerpt = cursor.excerpt()?;
3754
3755            // If we have already retrieved metadata for this excerpt, continue to use it.
3756            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3757                .as_mut()
3758                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3759            {
3760                Some(metadata)
3761            }
3762            // Otherwise, compute the intersection of the input range with the excerpt's range,
3763            // and retrieve the metadata for the resulting range.
3764            else {
3765                let region = cursor.region()?;
3766                let mut buffer_start;
3767                if region.is_main_buffer {
3768                    buffer_start = region.buffer_range.start;
3769                    if query_range.start > region.range.start {
3770                        let overshoot = query_range.start - region.range.start;
3771                        buffer_start.add_assign(&overshoot);
3772                    }
3773                    buffer_start = buffer_start.min(region.buffer_range.end);
3774                } else {
3775                    buffer_start = cursor.main_buffer_position()?;
3776                };
3777                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3778                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3779                    if excerpt.id == end_excerpt_id {
3780                        buffer_end = buffer_end.min(end_buffer_offset);
3781                    }
3782                }
3783
3784                if let Some(iterator) =
3785                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3786                {
3787                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3788                } else {
3789                    None
3790                }
3791            };
3792
3793            // Visit each metadata item.
3794            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3795            {
3796                // Find the multibuffer regions that contain the start and end of
3797                // the metadata item's range.
3798                if metadata_buffer_range.start > D::default() {
3799                    while let Some(region) = cursor.region() {
3800                        if region.is_main_buffer
3801                            && (region.buffer_range.end >= metadata_buffer_range.start
3802                                || cursor.is_at_end_of_excerpt())
3803                        {
3804                            break;
3805                        }
3806                        cursor.next();
3807                    }
3808                }
3809                let start_region = cursor.region()?;
3810                while let Some(region) = cursor.region() {
3811                    if region.is_main_buffer
3812                        && (region.buffer_range.end > metadata_buffer_range.end
3813                            || cursor.is_at_end_of_excerpt())
3814                    {
3815                        break;
3816                    }
3817                    cursor.next();
3818                }
3819                let end_region = cursor.region();
3820
3821                // Convert the metadata item's range into multibuffer coordinates.
3822                let mut start_position = start_region.range.start;
3823                let region_buffer_start = start_region.buffer_range.start;
3824                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3825                {
3826                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3827                    start_position = start_position.min(start_region.range.end);
3828                }
3829
3830                let mut end_position = max_position;
3831                if let Some(end_region) = &end_region {
3832                    end_position = end_region.range.start;
3833                    debug_assert!(end_region.is_main_buffer);
3834                    let region_buffer_start = end_region.buffer_range.start;
3835                    if metadata_buffer_range.end > region_buffer_start {
3836                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3837                    }
3838                    end_position = end_position.min(end_region.range.end);
3839                }
3840
3841                if start_position <= query_range.end && end_position >= query_range.start {
3842                    return Some((start_position..end_position, metadata, excerpt));
3843                }
3844            }
3845            // When there are no more metadata items for this excerpt, move to the next excerpt.
3846            else {
3847                current_excerpt_metadata.take();
3848                if let Some((end_excerpt_id, _)) = range_end {
3849                    if excerpt.id == end_excerpt_id {
3850                        return None;
3851                    }
3852                }
3853                cursor.next_excerpt();
3854            }
3855        })
3856    }
3857
3858    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3859        let offset = position.to_offset(self);
3860
3861        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3862        cursor.seek(&DimensionPair {
3863            key: offset,
3864            value: None,
3865        });
3866        cursor.seek_to_start_of_current_excerpt();
3867        let excerpt = cursor.excerpt()?;
3868
3869        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3870        let current_position = self
3871            .anchor_before(offset)
3872            .text_anchor
3873            .to_offset(&excerpt.buffer);
3874        let excerpt_end = excerpt
3875            .buffer
3876            .anchor_before(excerpt_end.min(current_position));
3877
3878        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3879            for hunk in diff.hunks_intersecting_range_rev(
3880                excerpt.range.context.start..excerpt_end,
3881                &excerpt.buffer,
3882            ) {
3883                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3884                if hunk_end >= current_position {
3885                    continue;
3886                }
3887                let start =
3888                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3889                        .to_point(&self);
3890                return Some(MultiBufferRow(start.row));
3891            }
3892        }
3893
3894        loop {
3895            cursor.prev_excerpt();
3896            let excerpt = cursor.excerpt()?;
3897
3898            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3899                continue;
3900            };
3901            let mut hunks =
3902                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3903            let Some(hunk) = hunks.next() else {
3904                continue;
3905            };
3906            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3907                .to_point(&self);
3908            return Some(MultiBufferRow(start.row));
3909        }
3910    }
3911
3912    pub fn has_diff_hunks(&self) -> bool {
3913        self.diffs.values().any(|diff| !diff.is_empty())
3914    }
3915
3916    pub fn surrounding_word<T: ToOffset>(
3917        &self,
3918        start: T,
3919        for_completion: bool,
3920    ) -> (Range<usize>, Option<CharKind>) {
3921        let mut start = start.to_offset(self);
3922        let mut end = start;
3923        let mut next_chars = self.chars_at(start).peekable();
3924        let mut prev_chars = self.reversed_chars_at(start).peekable();
3925
3926        let classifier = self
3927            .char_classifier_at(start)
3928            .for_completion(for_completion);
3929
3930        let word_kind = cmp::max(
3931            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3932            next_chars.peek().copied().map(|c| classifier.kind(c)),
3933        );
3934
3935        for ch in prev_chars {
3936            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3937                start -= ch.len_utf8();
3938            } else {
3939                break;
3940            }
3941        }
3942
3943        for ch in next_chars {
3944            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3945                end += ch.len_utf8();
3946            } else {
3947                break;
3948            }
3949        }
3950
3951        (start..end, word_kind)
3952    }
3953
3954    pub fn is_singleton(&self) -> bool {
3955        self.singleton
3956    }
3957
3958    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3959        if self.singleton {
3960            self.excerpts
3961                .iter()
3962                .next()
3963                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3964        } else {
3965            None
3966        }
3967    }
3968
3969    pub fn len(&self) -> usize {
3970        self.diff_transforms.summary().output.len
3971    }
3972
3973    pub fn is_empty(&self) -> bool {
3974        self.excerpts.summary().text.len == 0
3975    }
3976
3977    pub fn widest_line_number(&self) -> u32 {
3978        self.excerpts.summary().widest_line_number + 1
3979    }
3980
3981    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3982        let range = range.start.to_offset(self)..range.end.to_offset(self);
3983        let mut excerpts = self.cursor::<usize>();
3984        excerpts.seek(&range.start);
3985
3986        let mut chunk;
3987        let mut has_trailing_newline;
3988        let excerpt_bytes;
3989        if let Some(region) = excerpts.region() {
3990            let mut bytes = region.buffer.bytes_in_range(
3991                region.buffer_range.start + range.start - region.range.start
3992                    ..(region.buffer_range.start + range.end - region.range.start)
3993                        .min(region.buffer_range.end),
3994            );
3995            chunk = bytes.next().unwrap_or(&[][..]);
3996            excerpt_bytes = Some(bytes);
3997            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3998            if chunk.is_empty() && has_trailing_newline {
3999                chunk = b"\n";
4000                has_trailing_newline = false;
4001            }
4002        } else {
4003            chunk = &[][..];
4004            excerpt_bytes = None;
4005            has_trailing_newline = false;
4006        };
4007
4008        MultiBufferBytes {
4009            range,
4010            cursor: excerpts,
4011            excerpt_bytes,
4012            has_trailing_newline,
4013            chunk,
4014        }
4015    }
4016
4017    pub fn reversed_bytes_in_range<T: ToOffset>(
4018        &self,
4019        range: Range<T>,
4020    ) -> ReversedMultiBufferBytes {
4021        let range = range.start.to_offset(self)..range.end.to_offset(self);
4022        let mut chunks = self.reversed_chunks_in_range(range.clone());
4023        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4024        ReversedMultiBufferBytes {
4025            range,
4026            chunks,
4027            chunk,
4028        }
4029    }
4030
4031    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4032        let mut cursor = self.cursor::<Point>();
4033        cursor.seek(&Point::new(start_row.0, 0));
4034        let mut result = MultiBufferRows {
4035            point: Point::new(0, 0),
4036            is_empty: self.excerpts.is_empty(),
4037            cursor,
4038        };
4039        result.seek(start_row);
4040        result
4041    }
4042
4043    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4044        let mut chunks = MultiBufferChunks {
4045            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4046            range: 0..0,
4047            excerpts: self.excerpts.cursor(&()),
4048            diff_transforms: self.diff_transforms.cursor(&()),
4049            diffs: &self.diffs,
4050            diff_base_chunks: None,
4051            excerpt_chunks: None,
4052            buffer_chunk: None,
4053            language_aware,
4054        };
4055        let range = range.start.to_offset(self)..range.end.to_offset(self);
4056        chunks.seek(range);
4057        chunks
4058    }
4059
4060    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4061        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4062    }
4063
4064    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4065        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4066    }
4067
4068    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4069        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4070    }
4071
4072    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4073        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4074            buffer.clip_point_utf16(Unclipped(point), bias)
4075        })
4076    }
4077
4078    pub fn offset_to_point(&self, offset: usize) -> Point {
4079        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4080    }
4081
4082    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4083        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4084    }
4085
4086    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4087        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4088    }
4089
4090    pub fn point_to_offset(&self, point: Point) -> usize {
4091        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4092    }
4093
4094    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4095        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4096    }
4097
4098    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4099        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4100    }
4101
4102    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4103        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4104    }
4105
4106    fn clip_dimension<D>(
4107        &self,
4108        position: D,
4109        bias: Bias,
4110        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4111    ) -> D
4112    where
4113        D: TextDimension + Ord + Sub<D, Output = D>,
4114    {
4115        let mut cursor = self.cursor();
4116        cursor.seek(&position);
4117        if let Some(region) = cursor.region() {
4118            if position >= region.range.end {
4119                return region.range.end;
4120            }
4121            let overshoot = position - region.range.start;
4122            let mut buffer_position = region.buffer_range.start;
4123            buffer_position.add_assign(&overshoot);
4124            let clipped_buffer_position =
4125                clip_buffer_position(&region.buffer, buffer_position, bias);
4126            let mut position = region.range.start;
4127            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4128            position
4129        } else {
4130            D::from_text_summary(&self.text_summary())
4131        }
4132    }
4133
4134    fn convert_dimension<D1, D2>(
4135        &self,
4136        key: D1,
4137        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4138    ) -> D2
4139    where
4140        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4141        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4142    {
4143        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4144        cursor.seek(&DimensionPair { key, value: None });
4145        if let Some(region) = cursor.region() {
4146            if key >= region.range.end.key {
4147                return region.range.end.value.unwrap();
4148            }
4149            let start_key = region.range.start.key;
4150            let start_value = region.range.start.value.unwrap();
4151            let buffer_start_key = region.buffer_range.start.key;
4152            let buffer_start_value = region.buffer_range.start.value.unwrap();
4153            let mut buffer_key = buffer_start_key;
4154            buffer_key.add_assign(&(key - start_key));
4155            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4156            let mut result = start_value;
4157            result.add_assign(&(buffer_value - buffer_start_value));
4158            result
4159        } else {
4160            D2::from_text_summary(&self.text_summary())
4161        }
4162    }
4163
4164    pub fn point_to_buffer_offset<T: ToOffset>(
4165        &self,
4166        point: T,
4167    ) -> Option<(&BufferSnapshot, usize)> {
4168        let offset = point.to_offset(self);
4169        let mut cursor = self.cursor::<usize>();
4170        cursor.seek(&offset);
4171        let region = cursor.region()?;
4172        let overshoot = offset - region.range.start;
4173        let buffer_offset = region.buffer_range.start + overshoot;
4174        if buffer_offset == region.buffer.len() + 1
4175            && region.has_trailing_newline
4176            && !region.is_main_buffer
4177        {
4178            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4179        } else if buffer_offset > region.buffer.len() {
4180            return None;
4181        }
4182        Some((region.buffer, buffer_offset))
4183    }
4184
4185    pub fn point_to_buffer_point(
4186        &self,
4187        point: Point,
4188    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4189        let mut cursor = self.cursor::<Point>();
4190        cursor.seek(&point);
4191        let region = cursor.region()?;
4192        let overshoot = point - region.range.start;
4193        let buffer_point = region.buffer_range.start + overshoot;
4194        let excerpt = cursor.excerpt()?;
4195        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4196            && region.has_trailing_newline
4197            && !region.is_main_buffer
4198        {
4199            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4200        } else if buffer_point > region.buffer.max_point() {
4201            return None;
4202        }
4203        Some((region.buffer, buffer_point, excerpt.id))
4204    }
4205
4206    pub fn suggested_indents(
4207        &self,
4208        rows: impl IntoIterator<Item = u32>,
4209        cx: &App,
4210    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4211        let mut result = BTreeMap::new();
4212
4213        let mut rows_for_excerpt = Vec::new();
4214        let mut cursor = self.cursor::<Point>();
4215        let mut rows = rows.into_iter().peekable();
4216        let mut prev_row = u32::MAX;
4217        let mut prev_language_indent_size = IndentSize::default();
4218
4219        while let Some(row) = rows.next() {
4220            cursor.seek(&Point::new(row, 0));
4221            let Some(region) = cursor.region() else {
4222                continue;
4223            };
4224
4225            // Retrieve the language and indent size once for each disjoint region being indented.
4226            let single_indent_size = if row.saturating_sub(1) == prev_row {
4227                prev_language_indent_size
4228            } else {
4229                region
4230                    .buffer
4231                    .language_indent_size_at(Point::new(row, 0), cx)
4232            };
4233            prev_language_indent_size = single_indent_size;
4234            prev_row = row;
4235
4236            let start_buffer_row = region.buffer_range.start.row;
4237            let start_multibuffer_row = region.range.start.row;
4238            let end_multibuffer_row = region.range.end.row;
4239
4240            rows_for_excerpt.push(row);
4241            while let Some(next_row) = rows.peek().copied() {
4242                if end_multibuffer_row > next_row {
4243                    rows_for_excerpt.push(next_row);
4244                    rows.next();
4245                } else {
4246                    break;
4247                }
4248            }
4249
4250            let buffer_rows = rows_for_excerpt
4251                .drain(..)
4252                .map(|row| start_buffer_row + row - start_multibuffer_row);
4253            let buffer_indents = region
4254                .buffer
4255                .suggested_indents(buffer_rows, single_indent_size);
4256            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4257                (
4258                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4259                    indent,
4260                )
4261            });
4262            result.extend(multibuffer_indents);
4263        }
4264
4265        result
4266    }
4267
4268    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4269        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4270            let mut size = buffer.indent_size_for_line(range.start.row);
4271            size.len = size
4272                .len
4273                .min(range.end.column)
4274                .saturating_sub(range.start.column);
4275            size
4276        } else {
4277            IndentSize::spaces(0)
4278        }
4279    }
4280
4281    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4282        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4283            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4284        } else {
4285            LineIndent::spaces(0)
4286        }
4287    }
4288
4289    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4290        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4291
4292        if self.language_settings(cx).extend_comment_on_newline {
4293            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4294                let delimiters = language_scope.line_comment_prefixes();
4295                for delimiter in delimiters {
4296                    if *self
4297                        .chars_at(Point::new(row.0, indent.len() as u32))
4298                        .take(delimiter.chars().count())
4299                        .collect::<String>()
4300                        .as_str()
4301                        == **delimiter
4302                    {
4303                        indent.push_str(&delimiter);
4304                        break;
4305                    }
4306                }
4307            }
4308        }
4309
4310        indent
4311    }
4312
4313    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4314    where
4315        T: ToOffset,
4316    {
4317        for char in self.reversed_chars_at(position) {
4318            if !char.is_whitespace() {
4319                return false;
4320            }
4321            if char == '\n' {
4322                return true;
4323            }
4324        }
4325        return true;
4326    }
4327
4328    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4329        while row.0 > 0 {
4330            row.0 -= 1;
4331            if !self.is_line_blank(row) {
4332                return Some(row);
4333            }
4334        }
4335        None
4336    }
4337
4338    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4339        if let Some((_, range)) = self.buffer_line_for_row(row) {
4340            range.end.column - range.start.column
4341        } else {
4342            0
4343        }
4344    }
4345
4346    pub fn buffer_line_for_row(
4347        &self,
4348        row: MultiBufferRow,
4349    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4350        let mut cursor = self.cursor::<Point>();
4351        let point = Point::new(row.0, 0);
4352        cursor.seek(&point);
4353        let region = cursor.region()?;
4354        let overshoot = point.min(region.range.end) - region.range.start;
4355        let buffer_point = region.buffer_range.start + overshoot;
4356        if buffer_point.row > region.buffer_range.end.row {
4357            return None;
4358        }
4359        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4360        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4361            .min(region.buffer_range.end);
4362        Some((region.buffer, line_start..line_end))
4363    }
4364
4365    pub fn max_point(&self) -> Point {
4366        self.text_summary().lines
4367    }
4368
4369    pub fn max_row(&self) -> MultiBufferRow {
4370        MultiBufferRow(self.text_summary().lines.row)
4371    }
4372
4373    pub fn text_summary(&self) -> TextSummary {
4374        self.diff_transforms.summary().output
4375    }
4376
4377    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4378    where
4379        D: TextDimension,
4380        O: ToOffset,
4381    {
4382        let range = range.start.to_offset(self)..range.end.to_offset(self);
4383        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4384        cursor.seek(&range.start, Bias::Right, &());
4385
4386        let Some(first_transform) = cursor.item() else {
4387            return D::from_text_summary(&TextSummary::default());
4388        };
4389
4390        let diff_transform_start = cursor.start().0;
4391        let diff_transform_end = cursor.end(&()).0;
4392        let diff_start = range.start;
4393        let start_overshoot = diff_start - diff_transform_start;
4394        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4395
4396        let mut result = match first_transform {
4397            DiffTransform::BufferContent { .. } => {
4398                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4399                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4400                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4401            }
4402            DiffTransform::DeletedHunk {
4403                buffer_id,
4404                base_text_byte_range,
4405                has_trailing_newline,
4406                ..
4407            } => {
4408                let buffer_start = base_text_byte_range.start + start_overshoot;
4409                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4410                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4411                    panic!("{:?} is in non-existent deleted hunk", range.start)
4412                };
4413
4414                let include_trailing_newline =
4415                    *has_trailing_newline && range.end >= diff_transform_end;
4416                if include_trailing_newline {
4417                    buffer_end -= 1;
4418                }
4419
4420                let mut summary =
4421                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4422
4423                if include_trailing_newline {
4424                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4425                }
4426
4427                summary
4428            }
4429        };
4430        if range.end < diff_transform_end {
4431            return result;
4432        }
4433
4434        cursor.next(&());
4435        result.add_assign(&D::from_text_summary(&cursor.summary(
4436            &range.end,
4437            Bias::Right,
4438            &(),
4439        )));
4440
4441        let Some(last_transform) = cursor.item() else {
4442            return result;
4443        };
4444
4445        let overshoot = range.end - cursor.start().0;
4446        let suffix = match last_transform {
4447            DiffTransform::BufferContent { .. } => {
4448                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4449                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4450            }
4451            DiffTransform::DeletedHunk {
4452                base_text_byte_range,
4453                buffer_id,
4454                has_trailing_newline,
4455                ..
4456            } => {
4457                let buffer_end = base_text_byte_range.start + overshoot;
4458                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4459                    panic!("{:?} is in non-existent deleted hunk", range.end)
4460                };
4461
4462                let mut suffix = base_text
4463                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4464                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4465                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4466                }
4467                suffix
4468            }
4469        };
4470
4471        result.add_assign(&suffix);
4472        result
4473    }
4474
4475    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4476    where
4477        D: TextDimension,
4478    {
4479        // let mut range = range.start..range.end;
4480        let mut summary = D::zero(&());
4481        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4482        cursor.seek(&range.start, Bias::Right, &());
4483        if let Some(excerpt) = cursor.item() {
4484            let mut end_before_newline = cursor.end(&());
4485            if excerpt.has_trailing_newline {
4486                end_before_newline -= ExcerptOffset::new(1);
4487            }
4488
4489            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4490            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4491            let end_in_excerpt =
4492                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4493            summary.add_assign(
4494                &excerpt
4495                    .buffer
4496                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4497            );
4498
4499            if range.end > end_before_newline {
4500                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4501            }
4502
4503            cursor.next(&());
4504        }
4505
4506        if range.end > *cursor.start() {
4507            summary.add_assign(
4508                &cursor
4509                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4510                    .0,
4511            );
4512            if let Some(excerpt) = cursor.item() {
4513                range.end = cmp::max(*cursor.start(), range.end);
4514
4515                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4516                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4517                summary.add_assign(
4518                    &excerpt
4519                        .buffer
4520                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4521                );
4522            }
4523        }
4524
4525        summary
4526    }
4527
4528    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4529    where
4530        D: TextDimension + Ord + Sub<D, Output = D>,
4531    {
4532        self.summaries_for_anchors([anchor])[0]
4533    }
4534
4535    fn resolve_summary_for_anchor<D>(
4536        &self,
4537        anchor: &Anchor,
4538        excerpt_position: D,
4539        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4540    ) -> D
4541    where
4542        D: TextDimension + Ord + Sub<D, Output = D>,
4543    {
4544        loop {
4545            let transform_end_position = diff_transforms.end(&()).0 .0;
4546            let at_transform_end =
4547                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4548            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4549                diff_transforms.next(&());
4550                continue;
4551            }
4552
4553            let mut position = diff_transforms.start().1 .0;
4554            match diff_transforms.item() {
4555                Some(DiffTransform::DeletedHunk {
4556                    buffer_id,
4557                    base_text_byte_range,
4558                    ..
4559                }) => {
4560                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4561                        if let Some(base_text) =
4562                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4563                        {
4564                            if base_text.can_resolve(&diff_base_anchor) {
4565                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4566                                if base_text_offset >= base_text_byte_range.start
4567                                    && base_text_offset <= base_text_byte_range.end
4568                                {
4569                                    let position_in_hunk = base_text
4570                                        .text_summary_for_range::<D, _>(
4571                                            base_text_byte_range.start..base_text_offset,
4572                                        );
4573                                    position.add_assign(&position_in_hunk);
4574                                } else if at_transform_end {
4575                                    diff_transforms.next(&());
4576                                    continue;
4577                                }
4578                            }
4579                        }
4580                    }
4581                }
4582                _ => {
4583                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4584                        diff_transforms.next(&());
4585                        continue;
4586                    }
4587                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4588                    position.add_assign(&overshoot);
4589                }
4590            }
4591
4592            return position;
4593        }
4594    }
4595
4596    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4597        let mut cursor = self
4598            .excerpts
4599            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4600        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4601
4602        cursor.seek(&Some(locator), Bias::Left, &());
4603        if cursor.item().is_none() {
4604            cursor.next(&());
4605        }
4606
4607        let mut position = cursor.start().1;
4608        if let Some(excerpt) = cursor.item() {
4609            if excerpt.id == anchor.excerpt_id {
4610                let excerpt_buffer_start = excerpt
4611                    .buffer
4612                    .offset_for_anchor(&excerpt.range.context.start);
4613                let excerpt_buffer_end =
4614                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4615                let buffer_position = cmp::min(
4616                    excerpt_buffer_end,
4617                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4618                );
4619                if buffer_position > excerpt_buffer_start {
4620                    position.value += buffer_position - excerpt_buffer_start;
4621                }
4622            }
4623        }
4624        position
4625    }
4626
4627    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4628    where
4629        D: TextDimension + Ord + Sub<D, Output = D>,
4630        I: 'a + IntoIterator<Item = &'a Anchor>,
4631    {
4632        let mut anchors = anchors.into_iter().peekable();
4633        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4634        let mut diff_transforms_cursor = self
4635            .diff_transforms
4636            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4637        diff_transforms_cursor.next(&());
4638
4639        let mut summaries = Vec::new();
4640        while let Some(anchor) = anchors.peek() {
4641            let excerpt_id = anchor.excerpt_id;
4642            let excerpt_anchors = iter::from_fn(|| {
4643                let anchor = anchors.peek()?;
4644                if anchor.excerpt_id == excerpt_id {
4645                    Some(anchors.next().unwrap())
4646                } else {
4647                    None
4648                }
4649            });
4650
4651            let locator = self.excerpt_locator_for_id(excerpt_id);
4652            cursor.seek_forward(locator, Bias::Left, &());
4653            if cursor.item().is_none() {
4654                cursor.next(&());
4655            }
4656
4657            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4658            if let Some(excerpt) = cursor.item() {
4659                if excerpt.id != excerpt_id {
4660                    let position = self.resolve_summary_for_anchor(
4661                        &Anchor::min(),
4662                        excerpt_start_position,
4663                        &mut diff_transforms_cursor,
4664                    );
4665                    summaries.extend(excerpt_anchors.map(|_| position));
4666                    continue;
4667                }
4668                let excerpt_buffer_start =
4669                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4670                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4671                for (buffer_summary, anchor) in excerpt
4672                    .buffer
4673                    .summaries_for_anchors_with_payload::<D, _, _>(
4674                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4675                    )
4676                {
4677                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4678                    let mut position = excerpt_start_position;
4679                    if summary > excerpt_buffer_start {
4680                        position.add_assign(&(summary - excerpt_buffer_start));
4681                    }
4682
4683                    if position > diff_transforms_cursor.start().0 .0 {
4684                        diff_transforms_cursor.seek_forward(
4685                            &ExcerptDimension(position),
4686                            Bias::Left,
4687                            &(),
4688                        );
4689                    }
4690
4691                    summaries.push(self.resolve_summary_for_anchor(
4692                        anchor,
4693                        position,
4694                        &mut diff_transforms_cursor,
4695                    ));
4696                }
4697            } else {
4698                diff_transforms_cursor.seek_forward(
4699                    &ExcerptDimension(excerpt_start_position),
4700                    Bias::Left,
4701                    &(),
4702                );
4703                let position = self.resolve_summary_for_anchor(
4704                    &Anchor::max(),
4705                    excerpt_start_position,
4706                    &mut diff_transforms_cursor,
4707                );
4708                summaries.extend(excerpt_anchors.map(|_| position));
4709            }
4710        }
4711
4712        summaries
4713    }
4714
4715    pub fn dimensions_from_points<'a, D>(
4716        &'a self,
4717        points: impl 'a + IntoIterator<Item = Point>,
4718    ) -> impl 'a + Iterator<Item = D>
4719    where
4720        D: TextDimension + Sub<D, Output = D>,
4721    {
4722        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4723        cursor.seek(&DimensionPair {
4724            key: Point::default(),
4725            value: None,
4726        });
4727        let mut points = points.into_iter();
4728        iter::from_fn(move || {
4729            let point = points.next()?;
4730
4731            cursor.seek_forward(&DimensionPair {
4732                key: point,
4733                value: None,
4734            });
4735
4736            if let Some(region) = cursor.region() {
4737                let overshoot = point - region.range.start.key;
4738                let buffer_point = region.buffer_range.start.key + overshoot;
4739                let mut position = region.range.start.value.unwrap();
4740                position.add_assign(
4741                    &region
4742                        .buffer
4743                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4744                );
4745                if point == region.range.end.key && region.has_trailing_newline {
4746                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4747                }
4748                return Some(position);
4749            } else {
4750                return Some(D::from_text_summary(&self.text_summary()));
4751            }
4752        })
4753    }
4754
4755    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4756    where
4757        I: 'a + IntoIterator<Item = &'a Anchor>,
4758    {
4759        let mut anchors = anchors.into_iter().enumerate().peekable();
4760        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4761        cursor.next(&());
4762
4763        let mut result = Vec::new();
4764
4765        while let Some((_, anchor)) = anchors.peek() {
4766            let old_excerpt_id = anchor.excerpt_id;
4767
4768            // Find the location where this anchor's excerpt should be.
4769            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4770            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4771
4772            if cursor.item().is_none() {
4773                cursor.next(&());
4774            }
4775
4776            let next_excerpt = cursor.item();
4777            let prev_excerpt = cursor.prev_item();
4778
4779            // Process all of the anchors for this excerpt.
4780            while let Some((_, anchor)) = anchors.peek() {
4781                if anchor.excerpt_id != old_excerpt_id {
4782                    break;
4783                }
4784                let (anchor_ix, anchor) = anchors.next().unwrap();
4785                let mut anchor = *anchor;
4786
4787                // Leave min and max anchors unchanged if invalid or
4788                // if the old excerpt still exists at this location
4789                let mut kept_position = next_excerpt
4790                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4791                    || old_excerpt_id == ExcerptId::max()
4792                    || old_excerpt_id == ExcerptId::min();
4793
4794                // If the old excerpt no longer exists at this location, then attempt to
4795                // find an equivalent position for this anchor in an adjacent excerpt.
4796                if !kept_position {
4797                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4798                        if excerpt.contains(&anchor) {
4799                            anchor.excerpt_id = excerpt.id;
4800                            kept_position = true;
4801                            break;
4802                        }
4803                    }
4804                }
4805
4806                // If there's no adjacent excerpt that contains the anchor's position,
4807                // then report that the anchor has lost its position.
4808                if !kept_position {
4809                    anchor = if let Some(excerpt) = next_excerpt {
4810                        let mut text_anchor = excerpt
4811                            .range
4812                            .context
4813                            .start
4814                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4815                        if text_anchor
4816                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4817                            .is_gt()
4818                        {
4819                            text_anchor = excerpt.range.context.end;
4820                        }
4821                        Anchor {
4822                            buffer_id: Some(excerpt.buffer_id),
4823                            excerpt_id: excerpt.id,
4824                            text_anchor,
4825                            diff_base_anchor: None,
4826                        }
4827                    } else if let Some(excerpt) = prev_excerpt {
4828                        let mut text_anchor = excerpt
4829                            .range
4830                            .context
4831                            .end
4832                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4833                        if text_anchor
4834                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4835                            .is_lt()
4836                        {
4837                            text_anchor = excerpt.range.context.start;
4838                        }
4839                        Anchor {
4840                            buffer_id: Some(excerpt.buffer_id),
4841                            excerpt_id: excerpt.id,
4842                            text_anchor,
4843                            diff_base_anchor: None,
4844                        }
4845                    } else if anchor.text_anchor.bias == Bias::Left {
4846                        Anchor::min()
4847                    } else {
4848                        Anchor::max()
4849                    };
4850                }
4851
4852                result.push((anchor_ix, anchor, kept_position));
4853            }
4854        }
4855        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4856        result
4857    }
4858
4859    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4860        self.anchor_at(position, Bias::Left)
4861    }
4862
4863    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4864        self.anchor_at(position, Bias::Right)
4865    }
4866
4867    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4868        let offset = position.to_offset(self);
4869
4870        // Find the given position in the diff transforms. Determine the corresponding
4871        // offset in the excerpts, and whether the position is within a deleted hunk.
4872        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4873        diff_transforms.seek(&offset, Bias::Right, &());
4874
4875        if offset == diff_transforms.start().0 && bias == Bias::Left {
4876            if let Some(prev_item) = diff_transforms.prev_item() {
4877                match prev_item {
4878                    DiffTransform::DeletedHunk { .. } => {
4879                        diff_transforms.prev(&());
4880                    }
4881                    _ => {}
4882                }
4883            }
4884        }
4885        let offset_in_transform = offset - diff_transforms.start().0;
4886        let mut excerpt_offset = diff_transforms.start().1;
4887        let mut diff_base_anchor = None;
4888        if let Some(DiffTransform::DeletedHunk {
4889            buffer_id,
4890            base_text_byte_range,
4891            has_trailing_newline,
4892            ..
4893        }) = diff_transforms.item()
4894        {
4895            let diff = self.diffs.get(buffer_id).expect("missing diff");
4896            if offset_in_transform > base_text_byte_range.len() {
4897                debug_assert!(*has_trailing_newline);
4898                bias = Bias::Right;
4899            } else {
4900                diff_base_anchor = Some(
4901                    diff.base_text()
4902                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4903                );
4904                bias = Bias::Left;
4905            }
4906        } else {
4907            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4908        };
4909
4910        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4911            return Anchor {
4912                buffer_id: Some(buffer_id),
4913                excerpt_id: *excerpt_id,
4914                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4915                diff_base_anchor,
4916            };
4917        }
4918
4919        let mut excerpts = self
4920            .excerpts
4921            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4922        excerpts.seek(&excerpt_offset, Bias::Right, &());
4923        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4924            excerpts.prev(&());
4925        }
4926        if let Some(excerpt) = excerpts.item() {
4927            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4928            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4929                overshoot -= 1;
4930                bias = Bias::Right;
4931            }
4932
4933            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4934            let text_anchor =
4935                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4936            Anchor {
4937                buffer_id: Some(excerpt.buffer_id),
4938                excerpt_id: excerpt.id,
4939                text_anchor,
4940                diff_base_anchor,
4941            }
4942        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4943            Anchor::min()
4944        } else {
4945            Anchor::max()
4946        }
4947    }
4948
4949    /// Returns an anchor for the given excerpt and text anchor,
4950    /// returns None if the excerpt_id is no longer valid.
4951    pub fn anchor_in_excerpt(
4952        &self,
4953        excerpt_id: ExcerptId,
4954        text_anchor: text::Anchor,
4955    ) -> Option<Anchor> {
4956        let locator = self.excerpt_locator_for_id(excerpt_id);
4957        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4958        cursor.seek(locator, Bias::Left, &());
4959        if let Some(excerpt) = cursor.item() {
4960            if excerpt.id == excerpt_id {
4961                let text_anchor = excerpt.clip_anchor(text_anchor);
4962                drop(cursor);
4963                return Some(Anchor {
4964                    buffer_id: Some(excerpt.buffer_id),
4965                    excerpt_id,
4966                    text_anchor,
4967                    diff_base_anchor: None,
4968                });
4969            }
4970        }
4971        None
4972    }
4973
4974    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4975        Some(self.excerpt(excerpt_id)?.range.context.clone())
4976    }
4977
4978    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4979        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4980            true
4981        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4982            excerpt.buffer.can_resolve(&anchor.text_anchor)
4983        } else {
4984            false
4985        }
4986    }
4987
4988    pub fn excerpts(
4989        &self,
4990    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4991        self.excerpts
4992            .iter()
4993            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4994    }
4995
4996    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4997        let excerpts = self.excerpts.cursor(&());
4998        let diff_transforms = self.diff_transforms.cursor(&());
4999        MultiBufferCursor {
5000            excerpts,
5001            diff_transforms,
5002            diffs: &self.diffs,
5003            cached_region: None,
5004        }
5005    }
5006
5007    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5008        let start_locator = self.excerpt_locator_for_id(id);
5009        let mut excerpts = self
5010            .excerpts
5011            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5012        excerpts.seek(&Some(start_locator), Bias::Left, &());
5013        excerpts.prev(&());
5014
5015        let mut diff_transforms = self
5016            .diff_transforms
5017            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5018        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5019        if diff_transforms.end(&()).1 < excerpts.start().1 {
5020            diff_transforms.next(&());
5021        }
5022
5023        let excerpt = excerpts.item()?;
5024        Some(MultiBufferExcerpt {
5025            excerpt,
5026            offset: diff_transforms.start().0 .0,
5027            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5028            excerpt_offset: excerpts.start().1.clone(),
5029            diff_transforms,
5030        })
5031    }
5032
5033    pub fn excerpt_boundaries_in_range<R, T>(
5034        &self,
5035        range: R,
5036    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5037    where
5038        R: RangeBounds<T>,
5039        T: ToOffset,
5040    {
5041        let start_offset;
5042        let start = match range.start_bound() {
5043            Bound::Included(start) => {
5044                start_offset = start.to_offset(self);
5045                Bound::Included(start_offset)
5046            }
5047            Bound::Excluded(_) => {
5048                panic!("not supported")
5049            }
5050            Bound::Unbounded => {
5051                start_offset = 0;
5052                Bound::Unbounded
5053            }
5054        };
5055        let end = match range.end_bound() {
5056            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5057            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5058            Bound::Unbounded => Bound::Unbounded,
5059        };
5060        let bounds = (start, end);
5061
5062        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5063        cursor.seek(&DimensionPair {
5064            key: start_offset,
5065            value: None,
5066        });
5067
5068        if cursor
5069            .region()
5070            .is_some_and(|region| bounds.contains(&region.range.start.key))
5071        {
5072            cursor.prev_excerpt();
5073        } else {
5074            cursor.seek_to_start_of_current_excerpt();
5075        }
5076        let mut prev_region = cursor.region();
5077
5078        cursor.next_excerpt();
5079
5080        let mut visited_end = false;
5081        iter::from_fn(move || loop {
5082            if self.singleton {
5083                return None;
5084            }
5085
5086            let next_region = cursor.region();
5087            cursor.next_excerpt();
5088
5089            let next_region_start = if let Some(region) = &next_region {
5090                if !bounds.contains(&region.range.start.key) {
5091                    prev_region = next_region;
5092                    continue;
5093                }
5094                region.range.start.value.unwrap()
5095            } else {
5096                if !bounds.contains(&self.len()) {
5097                    return None;
5098                }
5099                self.max_point()
5100            };
5101            let next_region_end = if let Some(region) = cursor.region() {
5102                region.range.start.value.unwrap()
5103            } else {
5104                self.max_point()
5105            };
5106
5107            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5108                id: region.excerpt.id,
5109                buffer: region.excerpt.buffer.clone(),
5110                buffer_id: region.excerpt.buffer_id,
5111                range: region.excerpt.range.clone(),
5112                end_row: MultiBufferRow(next_region_start.row),
5113            });
5114
5115            let next = next_region.as_ref().map(|region| ExcerptInfo {
5116                id: region.excerpt.id,
5117                buffer: region.excerpt.buffer.clone(),
5118                buffer_id: region.excerpt.buffer_id,
5119                range: region.excerpt.range.clone(),
5120                end_row: if region.excerpt.has_trailing_newline {
5121                    MultiBufferRow(next_region_end.row - 1)
5122                } else {
5123                    MultiBufferRow(next_region_end.row)
5124                },
5125            });
5126
5127            if next.is_none() {
5128                if visited_end {
5129                    return None;
5130                } else {
5131                    visited_end = true;
5132                }
5133            }
5134
5135            let row = MultiBufferRow(next_region_start.row);
5136
5137            prev_region = next_region;
5138
5139            return Some(ExcerptBoundary { row, prev, next });
5140        })
5141    }
5142
5143    pub fn edit_count(&self) -> usize {
5144        self.edit_count
5145    }
5146
5147    pub fn non_text_state_update_count(&self) -> usize {
5148        self.non_text_state_update_count
5149    }
5150
5151    /// Returns the smallest enclosing bracket ranges containing the given range or
5152    /// None if no brackets contain range or the range is not contained in a single
5153    /// excerpt
5154    ///
5155    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5156    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5157        &self,
5158        range: Range<T>,
5159        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5160    ) -> Option<(Range<usize>, Range<usize>)> {
5161        let range = range.start.to_offset(self)..range.end.to_offset(self);
5162        let mut excerpt = self.excerpt_containing(range.clone())?;
5163        let buffer = excerpt.buffer();
5164        let excerpt_buffer_range = excerpt.buffer_range();
5165
5166        // Filter to ranges contained in the excerpt
5167        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5168            excerpt_buffer_range.contains(&open.start)
5169                && excerpt_buffer_range.contains(&close.end)
5170                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5171        };
5172
5173        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5174            excerpt.map_range_to_buffer(range),
5175            Some(&range_filter),
5176        )?;
5177
5178        Some((
5179            excerpt.map_range_from_buffer(open),
5180            excerpt.map_range_from_buffer(close),
5181        ))
5182    }
5183
5184    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5185    /// not contained in a single excerpt
5186    pub fn enclosing_bracket_ranges<T: ToOffset>(
5187        &self,
5188        range: Range<T>,
5189    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5190        let range = range.start.to_offset(self)..range.end.to_offset(self);
5191        let mut excerpt = self.excerpt_containing(range.clone())?;
5192
5193        Some(
5194            excerpt
5195                .buffer()
5196                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5197                .filter_map(move |pair| {
5198                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5199                        Some((
5200                            excerpt.map_range_from_buffer(pair.open_range),
5201                            excerpt.map_range_from_buffer(pair.close_range),
5202                        ))
5203                    } else {
5204                        None
5205                    }
5206                }),
5207        )
5208    }
5209
5210    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5211    /// not contained in a single excerpt
5212    pub fn text_object_ranges<T: ToOffset>(
5213        &self,
5214        range: Range<T>,
5215        options: TreeSitterOptions,
5216    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5217        let range = range.start.to_offset(self)..range.end.to_offset(self);
5218        self.excerpt_containing(range.clone())
5219            .map(|mut excerpt| {
5220                excerpt
5221                    .buffer()
5222                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5223                    .filter_map(move |(range, text_object)| {
5224                        if excerpt.contains_buffer_range(range.clone()) {
5225                            Some((excerpt.map_range_from_buffer(range), text_object))
5226                        } else {
5227                            None
5228                        }
5229                    })
5230            })
5231            .into_iter()
5232            .flatten()
5233    }
5234
5235    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5236    /// not contained in a single excerpt
5237    pub fn bracket_ranges<T: ToOffset>(
5238        &self,
5239        range: Range<T>,
5240    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5241        let range = range.start.to_offset(self)..range.end.to_offset(self);
5242        let mut excerpt = self.excerpt_containing(range.clone())?;
5243
5244        Some(
5245            excerpt
5246                .buffer()
5247                .bracket_ranges(excerpt.map_range_to_buffer(range))
5248                .filter_map(move |pair| {
5249                    let buffer_range = pair.open_range.start..pair.close_range.end;
5250                    if excerpt.contains_buffer_range(buffer_range) {
5251                        Some((
5252                            excerpt.map_range_from_buffer(pair.open_range),
5253                            excerpt.map_range_from_buffer(pair.close_range),
5254                        ))
5255                    } else {
5256                        None
5257                    }
5258                }),
5259        )
5260    }
5261
5262    pub fn redacted_ranges<'a, T: ToOffset>(
5263        &'a self,
5264        range: Range<T>,
5265        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5266    ) -> impl Iterator<Item = Range<usize>> + 'a {
5267        let range = range.start.to_offset(self)..range.end.to_offset(self);
5268        self.lift_buffer_metadata(range, move |buffer, range| {
5269            if redaction_enabled(buffer.file()) {
5270                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5271            } else {
5272                None
5273            }
5274        })
5275        .map(|(range, _, _)| range)
5276    }
5277
5278    pub fn runnable_ranges(
5279        &self,
5280        range: Range<Anchor>,
5281    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5282        let range = range.start.to_offset(self)..range.end.to_offset(self);
5283        self.lift_buffer_metadata(range, move |buffer, range| {
5284            Some(
5285                buffer
5286                    .runnable_ranges(range.clone())
5287                    .filter(move |runnable| {
5288                        runnable.run_range.start >= range.start
5289                            && runnable.run_range.end < range.end
5290                    })
5291                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5292            )
5293        })
5294        .map(|(run_range, runnable, _)| language::RunnableRange {
5295            run_range,
5296            ..runnable
5297        })
5298    }
5299
5300    pub fn line_indents(
5301        &self,
5302        start_row: MultiBufferRow,
5303        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5304    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5305        let max_point = self.max_point();
5306        let mut cursor = self.cursor::<Point>();
5307        cursor.seek(&Point::new(start_row.0, 0));
5308        iter::from_fn(move || {
5309            let mut region = cursor.region()?;
5310            while !buffer_filter(&region.excerpt.buffer) {
5311                cursor.next();
5312                region = cursor.region()?;
5313            }
5314            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5315            let buffer_start_row =
5316                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5317
5318            let buffer_end_row = if region.is_main_buffer
5319                && (region.has_trailing_newline || region.range.end == max_point)
5320            {
5321                region.buffer_range.end.row
5322            } else {
5323                region.buffer_range.end.row.saturating_sub(1)
5324            };
5325
5326            let line_indents = region
5327                .buffer
5328                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5329            cursor.next();
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 fn reversed_line_indents(
5339        &self,
5340        end_row: MultiBufferRow,
5341        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5342    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5343        let max_point = self.max_point();
5344        let mut cursor = self.cursor::<Point>();
5345        cursor.seek(&Point::new(end_row.0, 0));
5346        iter::from_fn(move || {
5347            let mut region = cursor.region()?;
5348            while !buffer_filter(&region.excerpt.buffer) {
5349                cursor.prev();
5350                region = cursor.region()?;
5351            }
5352
5353            let buffer_start_row = region.buffer_range.start.row;
5354            let buffer_end_row = if region.is_main_buffer
5355                && (region.has_trailing_newline || region.range.end == max_point)
5356            {
5357                region.buffer_range.end.row + 1
5358            } else {
5359                region.buffer_range.end.row
5360            };
5361
5362            let overshoot = end_row.0 - region.range.start.row;
5363            let buffer_end_row =
5364                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5365
5366            let line_indents = region
5367                .buffer
5368                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5369            cursor.prev();
5370            return Some(line_indents.map(move |(buffer_row, indent)| {
5371                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5372                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5373            }));
5374        })
5375        .flatten()
5376    }
5377
5378    pub async fn enclosing_indent(
5379        &self,
5380        mut target_row: MultiBufferRow,
5381    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5382        let max_row = MultiBufferRow(self.max_point().row);
5383        if target_row >= max_row {
5384            return None;
5385        }
5386
5387        let mut target_indent = self.line_indent_for_row(target_row);
5388
5389        // If the current row is at the start of an indented block, we want to return this
5390        // block as the enclosing indent.
5391        if !target_indent.is_line_empty() && target_row < max_row {
5392            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5393            if !next_line_indent.is_line_empty()
5394                && target_indent.raw_len() < next_line_indent.raw_len()
5395            {
5396                target_indent = next_line_indent;
5397                target_row.0 += 1;
5398            }
5399        }
5400
5401        const SEARCH_ROW_LIMIT: u32 = 25000;
5402        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5403        const YIELD_INTERVAL: u32 = 100;
5404
5405        let mut accessed_row_counter = 0;
5406
5407        // If there is a blank line at the current row, search for the next non indented lines
5408        if target_indent.is_line_empty() {
5409            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5410            let end =
5411                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5412
5413            let mut non_empty_line_above = None;
5414            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5415                if row < start {
5416                    break;
5417                }
5418                accessed_row_counter += 1;
5419                if accessed_row_counter == YIELD_INTERVAL {
5420                    accessed_row_counter = 0;
5421                    yield_now().await;
5422                }
5423                if !indent.is_line_empty() {
5424                    non_empty_line_above = Some((row, indent));
5425                    break;
5426                }
5427            }
5428
5429            let mut non_empty_line_below = None;
5430            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5431                if row > end {
5432                    break;
5433                }
5434                accessed_row_counter += 1;
5435                if accessed_row_counter == YIELD_INTERVAL {
5436                    accessed_row_counter = 0;
5437                    yield_now().await;
5438                }
5439                if !indent.is_line_empty() {
5440                    non_empty_line_below = Some((row, indent));
5441                    break;
5442                }
5443            }
5444
5445            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5446                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5447                    if above_indent.raw_len() >= below_indent.raw_len() {
5448                        (above_row, above_indent)
5449                    } else {
5450                        (below_row, below_indent)
5451                    }
5452                }
5453                (Some(above), None) => above,
5454                (None, Some(below)) => below,
5455                _ => return None,
5456            };
5457
5458            target_indent = indent;
5459            target_row = row;
5460        }
5461
5462        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5463        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5464
5465        let mut start_indent = None;
5466        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5467            if row < start {
5468                break;
5469            }
5470            accessed_row_counter += 1;
5471            if accessed_row_counter == YIELD_INTERVAL {
5472                accessed_row_counter = 0;
5473                yield_now().await;
5474            }
5475            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5476                start_indent = Some((row, indent));
5477                break;
5478            }
5479        }
5480        let (start_row, start_indent_size) = start_indent?;
5481
5482        let mut end_indent = (end, None);
5483        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5484            if row > end {
5485                break;
5486            }
5487            accessed_row_counter += 1;
5488            if accessed_row_counter == YIELD_INTERVAL {
5489                accessed_row_counter = 0;
5490                yield_now().await;
5491            }
5492            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5493                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5494                break;
5495            }
5496        }
5497        let (end_row, end_indent_size) = end_indent;
5498
5499        let indent = if let Some(end_indent_size) = end_indent_size {
5500            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5501                start_indent_size
5502            } else {
5503                end_indent_size
5504            }
5505        } else {
5506            start_indent_size
5507        };
5508
5509        Some((start_row..end_row, indent))
5510    }
5511
5512    pub fn indent_guides_in_range<T: ToPoint>(
5513        &self,
5514        range: Range<T>,
5515        ignore_disabled_for_language: bool,
5516        cx: &App,
5517    ) -> impl Iterator<Item = IndentGuide> {
5518        let range = range.start.to_point(self)..range.end.to_point(self);
5519        let start_row = MultiBufferRow(range.start.row);
5520        let end_row = MultiBufferRow(range.end.row);
5521
5522        let mut row_indents = self.line_indents(start_row, |buffer| {
5523            let settings =
5524                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5525            settings.indent_guides.enabled || ignore_disabled_for_language
5526        });
5527
5528        let mut result = Vec::new();
5529        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5530
5531        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5532            if first_row > end_row {
5533                break;
5534            }
5535            let current_depth = indent_stack.len() as u32;
5536
5537            let settings =
5538                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5539            let tab_size = settings.tab_size.get() as u32;
5540
5541            // When encountering empty, continue until found useful line indent
5542            // then add to the indent stack with the depth found
5543            let mut found_indent = false;
5544            let mut last_row = first_row;
5545            if line_indent.is_line_empty() {
5546                while !found_indent {
5547                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5548                        break;
5549                    };
5550                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5551                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5552                        break;
5553                    }
5554
5555                    if new_line_indent.is_line_empty() {
5556                        continue;
5557                    }
5558                    last_row = target_row.min(end_row);
5559                    line_indent = new_line_indent;
5560                    found_indent = true;
5561                    break;
5562                }
5563            } else {
5564                found_indent = true
5565            }
5566
5567            let depth = if found_indent {
5568                line_indent.len(tab_size) / tab_size
5569                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5570            } else {
5571                current_depth
5572            };
5573
5574            match depth.cmp(&current_depth) {
5575                cmp::Ordering::Less => {
5576                    for _ in 0..(current_depth - depth) {
5577                        let mut indent = indent_stack.pop().unwrap();
5578                        if last_row != first_row {
5579                            // In this case, we landed on an empty row, had to seek forward,
5580                            // and discovered that the indent we where on is ending.
5581                            // This means that the last display row must
5582                            // be on line that ends this indent range, so we
5583                            // should display the range up to the first non-empty line
5584                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5585                        }
5586
5587                        result.push(indent)
5588                    }
5589                }
5590                cmp::Ordering::Greater => {
5591                    for next_depth in current_depth..depth {
5592                        indent_stack.push(IndentGuide {
5593                            buffer_id: buffer.remote_id(),
5594                            start_row: first_row,
5595                            end_row: last_row,
5596                            depth: next_depth,
5597                            tab_size,
5598                            settings: settings.indent_guides,
5599                        });
5600                    }
5601                }
5602                _ => {}
5603            }
5604
5605            for indent in indent_stack.iter_mut() {
5606                indent.end_row = last_row;
5607            }
5608        }
5609
5610        result.extend(indent_stack);
5611        result.into_iter()
5612    }
5613
5614    pub fn trailing_excerpt_update_count(&self) -> usize {
5615        self.trailing_excerpt_update_count
5616    }
5617
5618    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5619        self.point_to_buffer_offset(point)
5620            .and_then(|(buffer, _)| buffer.file())
5621    }
5622
5623    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5624        self.point_to_buffer_offset(point)
5625            .and_then(|(buffer, offset)| buffer.language_at(offset))
5626    }
5627
5628    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5629        self.excerpts
5630            .first()
5631            .map(|excerpt| &excerpt.buffer)
5632            .map(|buffer| {
5633                language_settings(
5634                    buffer.language().map(|language| language.name()),
5635                    buffer.file(),
5636                    cx,
5637                )
5638            })
5639            .unwrap_or_else(move || self.language_settings_at(0, cx))
5640    }
5641
5642    pub fn language_settings_at<'a, T: ToOffset>(
5643        &'a self,
5644        point: T,
5645        cx: &'a App,
5646    ) -> Cow<'a, LanguageSettings> {
5647        let mut language = None;
5648        let mut file = None;
5649        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5650            language = buffer.language_at(offset);
5651            file = buffer.file();
5652        }
5653        language_settings(language.map(|l| l.name()), file, cx)
5654    }
5655
5656    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5657        self.point_to_buffer_offset(point)
5658            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5659    }
5660
5661    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5662        self.point_to_buffer_offset(point)
5663            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5664            .unwrap_or_default()
5665    }
5666
5667    pub fn language_indent_size_at<T: ToOffset>(
5668        &self,
5669        position: T,
5670        cx: &App,
5671    ) -> Option<IndentSize> {
5672        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5673        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5674    }
5675
5676    pub fn is_dirty(&self) -> bool {
5677        self.is_dirty
5678    }
5679
5680    pub fn has_deleted_file(&self) -> bool {
5681        self.has_deleted_file
5682    }
5683
5684    pub fn has_conflict(&self) -> bool {
5685        self.has_conflict
5686    }
5687
5688    pub fn has_diagnostics(&self) -> bool {
5689        self.excerpts
5690            .iter()
5691            .any(|excerpt| excerpt.buffer.has_diagnostics())
5692    }
5693
5694    pub fn diagnostic_group(
5695        &self,
5696        buffer_id: BufferId,
5697        group_id: usize,
5698    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5699        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5700            if buffer.remote_id() != buffer_id {
5701                return None;
5702            };
5703            Some(
5704                buffer
5705                    .diagnostic_group(group_id)
5706                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5707            )
5708        })
5709        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5710    }
5711
5712    pub fn diagnostics_in_range<'a, T>(
5713        &'a self,
5714        range: Range<T>,
5715    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5716    where
5717        T: 'a
5718            + text::ToOffset
5719            + text::FromAnchor
5720            + TextDimension
5721            + Ord
5722            + Sub<T, Output = T>
5723            + fmt::Debug,
5724    {
5725        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5726            Some(
5727                buffer
5728                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5729                    .map(|entry| (entry.range, entry.diagnostic)),
5730            )
5731        })
5732        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5733    }
5734
5735    pub fn syntax_ancestor<T: ToOffset>(
5736        &self,
5737        range: Range<T>,
5738    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5739        let range = range.start.to_offset(self)..range.end.to_offset(self);
5740        let mut excerpt = self.excerpt_containing(range.clone())?;
5741        let node = excerpt
5742            .buffer()
5743            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5744        let node_range = node.byte_range();
5745        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5746            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5747        } else {
5748            MultiOrSingleBufferOffsetRange::Single(node_range)
5749        };
5750        Some((node, range))
5751    }
5752
5753    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5754        let (excerpt_id, _, buffer) = self.as_singleton()?;
5755        let outline = buffer.outline(theme)?;
5756        Some(Outline::new(
5757            outline
5758                .items
5759                .into_iter()
5760                .flat_map(|item| {
5761                    Some(OutlineItem {
5762                        depth: item.depth,
5763                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5764                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5765                        text: item.text,
5766                        highlight_ranges: item.highlight_ranges,
5767                        name_ranges: item.name_ranges,
5768                        body_range: item.body_range.and_then(|body_range| {
5769                            Some(
5770                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5771                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5772                            )
5773                        }),
5774                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5775                            Some(
5776                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5777                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5778                            )
5779                        }),
5780                    })
5781                })
5782                .collect(),
5783        ))
5784    }
5785
5786    pub fn symbols_containing<T: ToOffset>(
5787        &self,
5788        offset: T,
5789        theme: Option<&SyntaxTheme>,
5790    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5791        let anchor = self.anchor_before(offset);
5792        let excerpt_id = anchor.excerpt_id;
5793        let excerpt = self.excerpt(excerpt_id)?;
5794        Some((
5795            excerpt.buffer_id,
5796            excerpt
5797                .buffer
5798                .symbols_containing(anchor.text_anchor, theme)
5799                .into_iter()
5800                .flatten()
5801                .flat_map(|item| {
5802                    Some(OutlineItem {
5803                        depth: item.depth,
5804                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5805                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5806                        text: item.text,
5807                        highlight_ranges: item.highlight_ranges,
5808                        name_ranges: item.name_ranges,
5809                        body_range: item.body_range.and_then(|body_range| {
5810                            Some(
5811                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5812                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5813                            )
5814                        }),
5815                        annotation_range: item.annotation_range.and_then(|body_range| {
5816                            Some(
5817                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5818                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5819                            )
5820                        }),
5821                    })
5822                })
5823                .collect(),
5824        ))
5825    }
5826
5827    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5828        if id == ExcerptId::min() {
5829            Locator::min_ref()
5830        } else if id == ExcerptId::max() {
5831            Locator::max_ref()
5832        } else {
5833            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5834            cursor.seek(&id, Bias::Left, &());
5835            if let Some(entry) = cursor.item() {
5836                if entry.id == id {
5837                    return &entry.locator;
5838                }
5839            }
5840            panic!("invalid excerpt id {:?}", id)
5841        }
5842    }
5843
5844    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5845    fn excerpt_locators_for_ids(
5846        &self,
5847        ids: impl IntoIterator<Item = ExcerptId>,
5848    ) -> SmallVec<[Locator; 1]> {
5849        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5850        sorted_ids.sort_unstable();
5851        let mut locators = SmallVec::new();
5852
5853        while sorted_ids.last() == Some(&ExcerptId::max()) {
5854            sorted_ids.pop();
5855            if let Some(mapping) = self.excerpt_ids.last() {
5856                locators.push(mapping.locator.clone());
5857            }
5858        }
5859
5860        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5861        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5862            sorted_ids.next();
5863            if let Some(mapping) = self.excerpt_ids.first() {
5864                locators.push(mapping.locator.clone());
5865            }
5866        }
5867
5868        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5869        for id in sorted_ids {
5870            if cursor.seek_forward(&id, Bias::Left, &()) {
5871                locators.push(cursor.item().unwrap().locator.clone());
5872            } else {
5873                panic!("invalid excerpt id {:?}", id);
5874            }
5875        }
5876
5877        locators.sort_unstable();
5878        locators
5879    }
5880
5881    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5882        Some(self.excerpt(excerpt_id)?.buffer_id)
5883    }
5884
5885    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5886        Some(&self.excerpt(excerpt_id)?.buffer)
5887    }
5888
5889    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5890        let mut cursor = self
5891            .excerpts
5892            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5893        let locator = self.excerpt_locator_for_id(excerpt_id);
5894        if cursor.seek(&Some(locator), Bias::Left, &()) {
5895            let start = cursor.start().1.clone();
5896            let end = cursor.end(&()).1;
5897            let mut diff_transforms = self
5898                .diff_transforms
5899                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5900            diff_transforms.seek(&start, Bias::Left, &());
5901            let overshoot = start.0 - diff_transforms.start().0 .0;
5902            let start = diff_transforms.start().1 .0 + overshoot;
5903            diff_transforms.seek(&end, Bias::Right, &());
5904            let overshoot = end.0 - diff_transforms.start().0 .0;
5905            let end = diff_transforms.start().1 .0 + overshoot;
5906            Some(start..end)
5907        } else {
5908            None
5909        }
5910    }
5911
5912    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5913        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5914        let locator = self.excerpt_locator_for_id(excerpt_id);
5915        if cursor.seek(&Some(locator), Bias::Left, &()) {
5916            if let Some(excerpt) = cursor.item() {
5917                return Some(excerpt.range.context.clone());
5918            }
5919        }
5920        None
5921    }
5922
5923    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5924        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5925        let locator = self.excerpt_locator_for_id(excerpt_id);
5926        cursor.seek(&Some(locator), Bias::Left, &());
5927        if let Some(excerpt) = cursor.item() {
5928            if excerpt.id == excerpt_id {
5929                return Some(excerpt);
5930            }
5931        }
5932        None
5933    }
5934
5935    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5936    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5937        let range = range.start.to_offset(self)..range.end.to_offset(self);
5938        let mut cursor = self.cursor::<usize>();
5939        cursor.seek(&range.start);
5940
5941        let start_excerpt = cursor.excerpt()?;
5942        if range.end != range.start {
5943            cursor.seek_forward(&range.end);
5944            if cursor.excerpt()?.id != start_excerpt.id {
5945                return None;
5946            }
5947        }
5948
5949        cursor.seek_to_start_of_current_excerpt();
5950        let region = cursor.region()?;
5951        let offset = region.range.start;
5952        let buffer_offset = region.buffer_range.start;
5953        let excerpt_offset = cursor.excerpts.start().clone();
5954        Some(MultiBufferExcerpt {
5955            diff_transforms: cursor.diff_transforms,
5956            excerpt: start_excerpt,
5957            offset,
5958            buffer_offset,
5959            excerpt_offset,
5960        })
5961    }
5962
5963    pub fn selections_in_range<'a>(
5964        &'a self,
5965        range: &'a Range<Anchor>,
5966        include_local: bool,
5967    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5968        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5969        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5970        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5971        cursor.seek(start_locator, Bias::Left, &());
5972        cursor
5973            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5974            .flat_map(move |excerpt| {
5975                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5976                if excerpt.id == range.start.excerpt_id {
5977                    query_range.start = range.start.text_anchor;
5978                }
5979                if excerpt.id == range.end.excerpt_id {
5980                    query_range.end = range.end.text_anchor;
5981                }
5982
5983                excerpt
5984                    .buffer
5985                    .selections_in_range(query_range, include_local)
5986                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5987                        selections.map(move |selection| {
5988                            let mut start = Anchor {
5989                                buffer_id: Some(excerpt.buffer_id),
5990                                excerpt_id: excerpt.id,
5991                                text_anchor: selection.start,
5992                                diff_base_anchor: None,
5993                            };
5994                            let mut end = Anchor {
5995                                buffer_id: Some(excerpt.buffer_id),
5996                                excerpt_id: excerpt.id,
5997                                text_anchor: selection.end,
5998                                diff_base_anchor: None,
5999                            };
6000                            if range.start.cmp(&start, self).is_gt() {
6001                                start = range.start;
6002                            }
6003                            if range.end.cmp(&end, self).is_lt() {
6004                                end = range.end;
6005                            }
6006
6007                            (
6008                                replica_id,
6009                                line_mode,
6010                                cursor_shape,
6011                                Selection {
6012                                    id: selection.id,
6013                                    start,
6014                                    end,
6015                                    reversed: selection.reversed,
6016                                    goal: selection.goal,
6017                                },
6018                            )
6019                        })
6020                    })
6021            })
6022    }
6023
6024    pub fn show_headers(&self) -> bool {
6025        self.show_headers
6026    }
6027
6028    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6029        self.diffs.get(&buffer_id)
6030    }
6031}
6032
6033#[cfg(any(test, feature = "test-support"))]
6034impl MultiBufferSnapshot {
6035    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6036        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6037        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6038        start..end
6039    }
6040
6041    #[cfg(any(test, feature = "test-support"))]
6042    fn check_invariants(&self) {
6043        let excerpts = self.excerpts.items(&());
6044        let excerpt_ids = self.excerpt_ids.items(&());
6045
6046        for (ix, excerpt) in excerpts.iter().enumerate() {
6047            if ix == 0 {
6048                if excerpt.locator <= Locator::min() {
6049                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6050                }
6051            } else if excerpt.locator <= excerpts[ix - 1].locator {
6052                panic!("excerpts are out-of-order: {:?}", excerpts);
6053            }
6054        }
6055
6056        for (ix, entry) in excerpt_ids.iter().enumerate() {
6057            if ix == 0 {
6058                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6059                    panic!("invalid first excerpt id {:?}", entry.id);
6060                }
6061            } else if entry.id <= excerpt_ids[ix - 1].id {
6062                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6063            }
6064        }
6065
6066        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6067            panic!(
6068                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6069                self.excerpts.summary().text.len,
6070                self.diff_transforms.summary().input,
6071                self.diff_transforms.items(&()),
6072            );
6073        }
6074
6075        let mut prev_transform: Option<&DiffTransform> = None;
6076        for item in self.diff_transforms.iter() {
6077            if let DiffTransform::BufferContent {
6078                summary,
6079                inserted_hunk_info,
6080            } = item
6081            {
6082                if let Some(DiffTransform::BufferContent {
6083                    inserted_hunk_info: prev_inserted_hunk_info,
6084                    ..
6085                }) = prev_transform
6086                {
6087                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6088                        panic!(
6089                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6090                            self.diff_transforms.items(&()));
6091                    }
6092                }
6093                if summary.len == 0 && !self.is_empty() {
6094                    panic!("empty buffer content transform");
6095                }
6096            }
6097            prev_transform = Some(item);
6098        }
6099    }
6100}
6101
6102impl<'a, D> MultiBufferCursor<'a, D>
6103where
6104    D: TextDimension + Ord + Sub<D, Output = D>,
6105{
6106    fn seek(&mut self, position: &D) {
6107        self.cached_region.take();
6108        self.diff_transforms
6109            .seek(&OutputDimension(*position), Bias::Right, &());
6110        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6111            self.diff_transforms.prev(&());
6112        }
6113
6114        let mut excerpt_position = self.diff_transforms.start().1 .0;
6115        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6116            let overshoot = *position - self.diff_transforms.start().0 .0;
6117            excerpt_position.add_assign(&overshoot);
6118        }
6119
6120        self.excerpts
6121            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6122        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6123            self.excerpts.prev(&());
6124        }
6125    }
6126
6127    fn seek_forward(&mut self, position: &D) {
6128        self.cached_region.take();
6129        self.diff_transforms
6130            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6131        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6132            self.diff_transforms.prev(&());
6133        }
6134
6135        let overshoot = *position - self.diff_transforms.start().0 .0;
6136        let mut excerpt_position = self.diff_transforms.start().1 .0;
6137        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6138            excerpt_position.add_assign(&overshoot);
6139        }
6140
6141        self.excerpts
6142            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6143        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6144            self.excerpts.prev(&());
6145        }
6146    }
6147
6148    fn next_excerpt(&mut self) {
6149        self.excerpts.next(&());
6150        self.seek_to_start_of_current_excerpt();
6151    }
6152
6153    fn prev_excerpt(&mut self) {
6154        self.excerpts.prev(&());
6155        self.seek_to_start_of_current_excerpt();
6156    }
6157
6158    fn seek_to_start_of_current_excerpt(&mut self) {
6159        self.cached_region.take();
6160        self.diff_transforms
6161            .seek(self.excerpts.start(), Bias::Left, &());
6162        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6163            && self.diff_transforms.start().1 < *self.excerpts.start()
6164            && self.diff_transforms.next_item().is_some()
6165        {
6166            self.diff_transforms.next(&());
6167        }
6168    }
6169
6170    fn next(&mut self) {
6171        self.cached_region.take();
6172        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6173            cmp::Ordering::Less => self.diff_transforms.next(&()),
6174            cmp::Ordering::Greater => self.excerpts.next(&()),
6175            cmp::Ordering::Equal => {
6176                self.diff_transforms.next(&());
6177                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6178                    || self.diff_transforms.item().is_none()
6179                {
6180                    self.excerpts.next(&());
6181                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6182                    self.diff_transforms.item()
6183                {
6184                    if self
6185                        .excerpts
6186                        .item()
6187                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6188                    {
6189                        self.excerpts.next(&());
6190                    }
6191                }
6192            }
6193        }
6194    }
6195
6196    fn prev(&mut self) {
6197        self.cached_region.take();
6198        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6199            cmp::Ordering::Less => self.excerpts.prev(&()),
6200            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6201            cmp::Ordering::Equal => {
6202                self.diff_transforms.prev(&());
6203                if self.diff_transforms.start().1 < *self.excerpts.start()
6204                    || self.diff_transforms.item().is_none()
6205                {
6206                    self.excerpts.prev(&());
6207                }
6208            }
6209        }
6210    }
6211
6212    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6213        if self.cached_region.is_none() {
6214            self.cached_region = self.build_region();
6215        }
6216        self.cached_region.clone()
6217    }
6218
6219    fn is_at_end_of_excerpt(&mut self) -> bool {
6220        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6221            return false;
6222        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6223            || self.diff_transforms.item().is_none()
6224        {
6225            return true;
6226        }
6227
6228        let next_transform = self.diff_transforms.next_item();
6229        next_transform.map_or(true, |next_transform| match next_transform {
6230            DiffTransform::BufferContent { .. } => true,
6231            DiffTransform::DeletedHunk { hunk_info, .. } => self
6232                .excerpts
6233                .item()
6234                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6235        })
6236    }
6237
6238    fn main_buffer_position(&self) -> Option<D> {
6239        let excerpt = self.excerpts.item()?;
6240        let buffer = &excerpt.buffer;
6241        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6242        let mut buffer_start = buffer_context_start;
6243        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6244        buffer_start.add_assign(&overshoot);
6245        Some(buffer_start)
6246    }
6247
6248    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6249        let excerpt = self.excerpts.item()?;
6250        match self.diff_transforms.item()? {
6251            DiffTransform::DeletedHunk {
6252                buffer_id,
6253                base_text_byte_range,
6254                has_trailing_newline,
6255                hunk_info,
6256                ..
6257            } => {
6258                let diff = self.diffs.get(&buffer_id)?;
6259                let buffer = diff.base_text();
6260                let mut rope_cursor = buffer.as_rope().cursor(0);
6261                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6262                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6263                let mut buffer_end = buffer_start;
6264                buffer_end.add_assign(&buffer_range_len);
6265                let start = self.diff_transforms.start().0 .0;
6266                let end = self.diff_transforms.end(&()).0 .0;
6267                return Some(MultiBufferRegion {
6268                    buffer,
6269                    excerpt,
6270                    has_trailing_newline: *has_trailing_newline,
6271                    is_main_buffer: false,
6272                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6273                        hunk_info.hunk_secondary_status,
6274                    )),
6275                    buffer_range: buffer_start..buffer_end,
6276                    range: start..end,
6277                });
6278            }
6279            DiffTransform::BufferContent {
6280                inserted_hunk_info, ..
6281            } => {
6282                let buffer = &excerpt.buffer;
6283                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6284
6285                let mut start = self.diff_transforms.start().0 .0;
6286                let mut buffer_start = buffer_context_start;
6287                if self.diff_transforms.start().1 < *self.excerpts.start() {
6288                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6289                    start.add_assign(&overshoot);
6290                } else {
6291                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6292                    buffer_start.add_assign(&overshoot);
6293                }
6294
6295                let mut end;
6296                let mut buffer_end;
6297                let has_trailing_newline;
6298                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6299                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6300                    end = self.diff_transforms.end(&()).0 .0;
6301                    buffer_end = buffer_context_start;
6302                    buffer_end.add_assign(&overshoot);
6303                    has_trailing_newline = false;
6304                } else {
6305                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6306                    end = self.diff_transforms.start().0 .0;
6307                    end.add_assign(&overshoot);
6308                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6309                    has_trailing_newline = excerpt.has_trailing_newline;
6310                };
6311
6312                Some(MultiBufferRegion {
6313                    buffer,
6314                    excerpt,
6315                    has_trailing_newline,
6316                    is_main_buffer: true,
6317                    diff_hunk_status: inserted_hunk_info
6318                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6319                    buffer_range: buffer_start..buffer_end,
6320                    range: start..end,
6321                })
6322            }
6323        }
6324    }
6325
6326    fn excerpt(&self) -> Option<&'a Excerpt> {
6327        self.excerpts.item()
6328    }
6329}
6330
6331impl History {
6332    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6333        self.transaction_depth += 1;
6334        if self.transaction_depth == 1 {
6335            let id = self.next_transaction_id.tick();
6336            self.undo_stack.push(Transaction {
6337                id,
6338                buffer_transactions: Default::default(),
6339                first_edit_at: now,
6340                last_edit_at: now,
6341                suppress_grouping: false,
6342            });
6343            Some(id)
6344        } else {
6345            None
6346        }
6347    }
6348
6349    fn end_transaction(
6350        &mut self,
6351        now: Instant,
6352        buffer_transactions: HashMap<BufferId, TransactionId>,
6353    ) -> bool {
6354        assert_ne!(self.transaction_depth, 0);
6355        self.transaction_depth -= 1;
6356        if self.transaction_depth == 0 {
6357            if buffer_transactions.is_empty() {
6358                self.undo_stack.pop();
6359                false
6360            } else {
6361                self.redo_stack.clear();
6362                let transaction = self.undo_stack.last_mut().unwrap();
6363                transaction.last_edit_at = now;
6364                for (buffer_id, transaction_id) in buffer_transactions {
6365                    transaction
6366                        .buffer_transactions
6367                        .entry(buffer_id)
6368                        .or_insert(transaction_id);
6369                }
6370                true
6371            }
6372        } else {
6373            false
6374        }
6375    }
6376
6377    fn push_transaction<'a, T>(
6378        &mut self,
6379        buffer_transactions: T,
6380        now: Instant,
6381        cx: &Context<MultiBuffer>,
6382    ) where
6383        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6384    {
6385        assert_eq!(self.transaction_depth, 0);
6386        let transaction = Transaction {
6387            id: self.next_transaction_id.tick(),
6388            buffer_transactions: buffer_transactions
6389                .into_iter()
6390                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6391                .collect(),
6392            first_edit_at: now,
6393            last_edit_at: now,
6394            suppress_grouping: false,
6395        };
6396        if !transaction.buffer_transactions.is_empty() {
6397            self.undo_stack.push(transaction);
6398            self.redo_stack.clear();
6399        }
6400    }
6401
6402    fn finalize_last_transaction(&mut self) {
6403        if let Some(transaction) = self.undo_stack.last_mut() {
6404            transaction.suppress_grouping = true;
6405        }
6406    }
6407
6408    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6409        if let Some(ix) = self
6410            .undo_stack
6411            .iter()
6412            .rposition(|transaction| transaction.id == transaction_id)
6413        {
6414            Some(self.undo_stack.remove(ix))
6415        } else if let Some(ix) = self
6416            .redo_stack
6417            .iter()
6418            .rposition(|transaction| transaction.id == transaction_id)
6419        {
6420            Some(self.redo_stack.remove(ix))
6421        } else {
6422            None
6423        }
6424    }
6425
6426    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6427        self.undo_stack
6428            .iter()
6429            .find(|transaction| transaction.id == transaction_id)
6430            .or_else(|| {
6431                self.redo_stack
6432                    .iter()
6433                    .find(|transaction| transaction.id == transaction_id)
6434            })
6435    }
6436
6437    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6438        self.undo_stack
6439            .iter_mut()
6440            .find(|transaction| transaction.id == transaction_id)
6441            .or_else(|| {
6442                self.redo_stack
6443                    .iter_mut()
6444                    .find(|transaction| transaction.id == transaction_id)
6445            })
6446    }
6447
6448    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6449        assert_eq!(self.transaction_depth, 0);
6450        if let Some(transaction) = self.undo_stack.pop() {
6451            self.redo_stack.push(transaction);
6452            self.redo_stack.last_mut()
6453        } else {
6454            None
6455        }
6456    }
6457
6458    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6459        assert_eq!(self.transaction_depth, 0);
6460        if let Some(transaction) = self.redo_stack.pop() {
6461            self.undo_stack.push(transaction);
6462            self.undo_stack.last_mut()
6463        } else {
6464            None
6465        }
6466    }
6467
6468    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6469        let ix = self
6470            .undo_stack
6471            .iter()
6472            .rposition(|transaction| transaction.id == transaction_id)?;
6473        let transaction = self.undo_stack.remove(ix);
6474        self.redo_stack.push(transaction);
6475        self.redo_stack.last()
6476    }
6477
6478    fn group(&mut self) -> Option<TransactionId> {
6479        let mut count = 0;
6480        let mut transactions = self.undo_stack.iter();
6481        if let Some(mut transaction) = transactions.next_back() {
6482            while let Some(prev_transaction) = transactions.next_back() {
6483                if !prev_transaction.suppress_grouping
6484                    && transaction.first_edit_at - prev_transaction.last_edit_at
6485                        <= self.group_interval
6486                {
6487                    transaction = prev_transaction;
6488                    count += 1;
6489                } else {
6490                    break;
6491                }
6492            }
6493        }
6494        self.group_trailing(count)
6495    }
6496
6497    fn group_until(&mut self, transaction_id: TransactionId) {
6498        let mut count = 0;
6499        for transaction in self.undo_stack.iter().rev() {
6500            if transaction.id == transaction_id {
6501                self.group_trailing(count);
6502                break;
6503            } else if transaction.suppress_grouping {
6504                break;
6505            } else {
6506                count += 1;
6507            }
6508        }
6509    }
6510
6511    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6512        let new_len = self.undo_stack.len() - n;
6513        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6514        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6515            if let Some(transaction) = transactions_to_merge.last() {
6516                last_transaction.last_edit_at = transaction.last_edit_at;
6517            }
6518            for to_merge in transactions_to_merge {
6519                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6520                    last_transaction
6521                        .buffer_transactions
6522                        .entry(*buffer_id)
6523                        .or_insert(*transaction_id);
6524                }
6525            }
6526        }
6527
6528        self.undo_stack.truncate(new_len);
6529        self.undo_stack.last().map(|t| t.id)
6530    }
6531}
6532
6533impl Excerpt {
6534    fn new(
6535        id: ExcerptId,
6536        locator: Locator,
6537        buffer_id: BufferId,
6538        buffer: BufferSnapshot,
6539        range: ExcerptRange<text::Anchor>,
6540        has_trailing_newline: bool,
6541    ) -> Self {
6542        Excerpt {
6543            id,
6544            locator,
6545            max_buffer_row: range.context.end.to_point(&buffer).row,
6546            text_summary: buffer
6547                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6548            buffer_id,
6549            buffer,
6550            range,
6551            has_trailing_newline,
6552        }
6553    }
6554
6555    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6556        let content_start = self.range.context.start.to_offset(&self.buffer);
6557        let chunks_start = content_start + range.start;
6558        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6559
6560        let footer_height = if self.has_trailing_newline
6561            && range.start <= self.text_summary.len
6562            && range.end > self.text_summary.len
6563        {
6564            1
6565        } else {
6566            0
6567        };
6568
6569        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6570
6571        ExcerptChunks {
6572            excerpt_id: self.id,
6573            content_chunks,
6574            footer_height,
6575        }
6576    }
6577
6578    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6579        let content_start = self.range.context.start.to_offset(&self.buffer);
6580        let chunks_start = content_start + range.start;
6581        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6582        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6583        excerpt_chunks.footer_height = if self.has_trailing_newline
6584            && range.start <= self.text_summary.len
6585            && range.end > self.text_summary.len
6586        {
6587            1
6588        } else {
6589            0
6590        };
6591    }
6592
6593    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6594        if text_anchor
6595            .cmp(&self.range.context.start, &self.buffer)
6596            .is_lt()
6597        {
6598            self.range.context.start
6599        } else if text_anchor
6600            .cmp(&self.range.context.end, &self.buffer)
6601            .is_gt()
6602        {
6603            self.range.context.end
6604        } else {
6605            text_anchor
6606        }
6607    }
6608
6609    fn contains(&self, anchor: &Anchor) -> bool {
6610        Some(self.buffer_id) == anchor.buffer_id
6611            && self
6612                .range
6613                .context
6614                .start
6615                .cmp(&anchor.text_anchor, &self.buffer)
6616                .is_le()
6617            && self
6618                .range
6619                .context
6620                .end
6621                .cmp(&anchor.text_anchor, &self.buffer)
6622                .is_ge()
6623    }
6624
6625    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6626    fn buffer_start_offset(&self) -> usize {
6627        self.range.context.start.to_offset(&self.buffer)
6628    }
6629
6630    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6631    fn buffer_end_offset(&self) -> usize {
6632        self.buffer_start_offset() + self.text_summary.len
6633    }
6634}
6635
6636impl<'a> MultiBufferExcerpt<'a> {
6637    pub fn id(&self) -> ExcerptId {
6638        self.excerpt.id
6639    }
6640
6641    pub fn buffer_id(&self) -> BufferId {
6642        self.excerpt.buffer_id
6643    }
6644
6645    pub fn start_anchor(&self) -> Anchor {
6646        Anchor {
6647            buffer_id: Some(self.excerpt.buffer_id),
6648            excerpt_id: self.excerpt.id,
6649            text_anchor: self.excerpt.range.context.start,
6650            diff_base_anchor: None,
6651        }
6652    }
6653
6654    pub fn end_anchor(&self) -> Anchor {
6655        Anchor {
6656            buffer_id: Some(self.excerpt.buffer_id),
6657            excerpt_id: self.excerpt.id,
6658            text_anchor: self.excerpt.range.context.end,
6659            diff_base_anchor: None,
6660        }
6661    }
6662
6663    pub fn buffer(&self) -> &'a BufferSnapshot {
6664        &self.excerpt.buffer
6665    }
6666
6667    pub fn buffer_range(&self) -> Range<usize> {
6668        self.buffer_offset
6669            ..self
6670                .excerpt
6671                .range
6672                .context
6673                .end
6674                .to_offset(&self.excerpt.buffer.text)
6675    }
6676
6677    pub fn start_offset(&self) -> usize {
6678        self.offset
6679    }
6680
6681    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6682    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6683        self.map_range_to_buffer(offset..offset).start
6684    }
6685
6686    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6687    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6688        self.diff_transforms
6689            .seek(&OutputDimension(range.start), Bias::Right, &());
6690        let start = self.map_offset_to_buffer_internal(range.start);
6691        let end = if range.end > range.start {
6692            self.diff_transforms
6693                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6694            self.map_offset_to_buffer_internal(range.end)
6695        } else {
6696            start
6697        };
6698        start..end
6699    }
6700
6701    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6702        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6703        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6704            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6705        };
6706        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6707        self.buffer_offset + offset_in_excerpt
6708    }
6709
6710    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6711    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6712        self.map_range_from_buffer(buffer_offset..buffer_offset)
6713            .start
6714    }
6715
6716    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6717    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6718        if buffer_range.start < self.buffer_offset {
6719            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6720            return buffer_range;
6721        }
6722        let overshoot = buffer_range.start - self.buffer_offset;
6723        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6724        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6725        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6726            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6727            return buffer_range;
6728        }
6729        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6730        let start = self.diff_transforms.start().0 .0 + overshoot;
6731
6732        let end = if buffer_range.end > buffer_range.start {
6733            let overshoot = buffer_range.end - self.buffer_offset;
6734            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6735            self.diff_transforms
6736                .seek_forward(&excerpt_offset, Bias::Right, &());
6737            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6738            self.diff_transforms.start().0 .0 + overshoot
6739        } else {
6740            start
6741        };
6742
6743        start..end
6744    }
6745
6746    /// Returns true if the entirety of the given range is in the buffer's excerpt
6747    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6748        range.start >= self.excerpt.buffer_start_offset()
6749            && range.end <= self.excerpt.buffer_end_offset()
6750    }
6751
6752    pub fn max_buffer_row(&self) -> u32 {
6753        self.excerpt.max_buffer_row
6754    }
6755}
6756
6757impl ExcerptId {
6758    pub fn min() -> Self {
6759        Self(0)
6760    }
6761
6762    pub fn max() -> Self {
6763        Self(usize::MAX)
6764    }
6765
6766    pub fn to_proto(&self) -> u64 {
6767        self.0 as _
6768    }
6769
6770    pub fn from_proto(proto: u64) -> Self {
6771        Self(proto as _)
6772    }
6773
6774    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6775        let a = snapshot.excerpt_locator_for_id(*self);
6776        let b = snapshot.excerpt_locator_for_id(*other);
6777        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6778    }
6779}
6780
6781impl From<ExcerptId> for usize {
6782    fn from(val: ExcerptId) -> Self {
6783        val.0
6784    }
6785}
6786
6787impl fmt::Debug for Excerpt {
6788    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6789        f.debug_struct("Excerpt")
6790            .field("id", &self.id)
6791            .field("locator", &self.locator)
6792            .field("buffer_id", &self.buffer_id)
6793            .field("range", &self.range)
6794            .field("text_summary", &self.text_summary)
6795            .field("has_trailing_newline", &self.has_trailing_newline)
6796            .finish()
6797    }
6798}
6799
6800impl sum_tree::Item for Excerpt {
6801    type Summary = ExcerptSummary;
6802
6803    fn summary(&self, _cx: &()) -> Self::Summary {
6804        let mut text = self.text_summary;
6805        if self.has_trailing_newline {
6806            text += TextSummary::from("\n");
6807        }
6808        ExcerptSummary {
6809            excerpt_id: self.id,
6810            excerpt_locator: self.locator.clone(),
6811            widest_line_number: self.max_buffer_row,
6812            text,
6813        }
6814    }
6815}
6816
6817impl sum_tree::Item for ExcerptIdMapping {
6818    type Summary = ExcerptId;
6819
6820    fn summary(&self, _cx: &()) -> Self::Summary {
6821        self.id
6822    }
6823}
6824
6825impl sum_tree::KeyedItem for ExcerptIdMapping {
6826    type Key = ExcerptId;
6827
6828    fn key(&self) -> Self::Key {
6829        self.id
6830    }
6831}
6832
6833impl DiffTransform {
6834    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6835        match self {
6836            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6837            DiffTransform::BufferContent {
6838                inserted_hunk_info, ..
6839            } => *inserted_hunk_info,
6840        }
6841    }
6842}
6843
6844impl sum_tree::Item for DiffTransform {
6845    type Summary = DiffTransformSummary;
6846
6847    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6848        match self {
6849            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6850                input: *summary,
6851                output: *summary,
6852            },
6853            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6854                input: TextSummary::default(),
6855                output: *summary,
6856            },
6857        }
6858    }
6859}
6860
6861impl DiffTransformSummary {
6862    fn excerpt_len(&self) -> ExcerptOffset {
6863        ExcerptOffset::new(self.input.len)
6864    }
6865}
6866
6867impl sum_tree::Summary for DiffTransformSummary {
6868    type Context = ();
6869
6870    fn zero(_: &Self::Context) -> Self {
6871        DiffTransformSummary {
6872            input: TextSummary::default(),
6873            output: TextSummary::default(),
6874        }
6875    }
6876
6877    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6878        self.input += &summary.input;
6879        self.output += &summary.output;
6880    }
6881}
6882
6883impl sum_tree::Summary for ExcerptId {
6884    type Context = ();
6885
6886    fn zero(_cx: &()) -> Self {
6887        Default::default()
6888    }
6889
6890    fn add_summary(&mut self, other: &Self, _: &()) {
6891        *self = *other;
6892    }
6893}
6894
6895impl sum_tree::Summary for ExcerptSummary {
6896    type Context = ();
6897
6898    fn zero(_cx: &()) -> Self {
6899        Default::default()
6900    }
6901
6902    fn add_summary(&mut self, summary: &Self, _: &()) {
6903        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6904        self.excerpt_locator = summary.excerpt_locator.clone();
6905        self.text.add_summary(&summary.text, &());
6906        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6907    }
6908}
6909
6910impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6911    fn zero(_cx: &()) -> Self {
6912        Default::default()
6913    }
6914
6915    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6916        self.value += summary.text.len;
6917    }
6918}
6919
6920impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6921    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6922        Ord::cmp(&self.value, &cursor_location.text.len)
6923    }
6924}
6925
6926impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6927    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6928        Ord::cmp(&Some(self), cursor_location)
6929    }
6930}
6931
6932impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6933    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6934        Ord::cmp(self, &cursor_location.excerpt_locator)
6935    }
6936}
6937
6938impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6939    fn zero(_cx: &()) -> Self {
6940        Default::default()
6941    }
6942
6943    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6944        self.value += summary.text.lines;
6945    }
6946}
6947
6948impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6949    for ExcerptDimension<D>
6950{
6951    fn zero(_: &()) -> Self {
6952        ExcerptDimension(D::default())
6953    }
6954
6955    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6956        self.0.add_assign(&D::from_text_summary(&summary.text))
6957    }
6958}
6959
6960impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6961    fn zero(_cx: &()) -> Self {
6962        Default::default()
6963    }
6964
6965    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6966        *self = Some(&summary.excerpt_locator);
6967    }
6968}
6969
6970impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6971    fn zero(_cx: &()) -> Self {
6972        Default::default()
6973    }
6974
6975    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6976        *self = Some(summary.excerpt_id);
6977    }
6978}
6979
6980#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6981struct ExcerptDimension<T>(T);
6982
6983#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6984struct OutputDimension<T>(T);
6985
6986impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6987    fn zero(_: &()) -> Self {
6988        ExcerptOffset::new(0)
6989    }
6990
6991    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6992        self.value += summary.input.len;
6993    }
6994}
6995
6996impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6997    fn zero(_: &()) -> Self {
6998        ExcerptPoint::new(0, 0)
6999    }
7000
7001    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7002        self.value += summary.input.lines;
7003    }
7004}
7005
7006impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7007    for ExcerptDimension<D>
7008{
7009    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7010        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7011    }
7012}
7013
7014impl<D: TextDimension + Ord>
7015    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7016    for ExcerptDimension<D>
7017{
7018    fn cmp(
7019        &self,
7020        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7021        _: &(),
7022    ) -> cmp::Ordering {
7023        Ord::cmp(&self.0, &cursor_location.1 .0)
7024    }
7025}
7026
7027impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7028    fn zero(_: &()) -> Self {
7029        ExcerptDimension(D::default())
7030    }
7031
7032    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7033        self.0.add_assign(&D::from_text_summary(&summary.input))
7034    }
7035}
7036
7037impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7038    fn zero(_: &()) -> Self {
7039        OutputDimension(D::default())
7040    }
7041
7042    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7043        self.0.add_assign(&D::from_text_summary(&summary.output))
7044    }
7045}
7046
7047impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7048    fn zero(_: &()) -> Self {
7049        TextSummary::default()
7050    }
7051
7052    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7053        *self += summary.output
7054    }
7055}
7056
7057impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7058    fn zero(_: &()) -> Self {
7059        0
7060    }
7061
7062    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7063        *self += summary.output.len
7064    }
7065}
7066
7067impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7068    fn zero(_: &()) -> Self {
7069        Point::new(0, 0)
7070    }
7071
7072    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7073        *self += summary.output.lines
7074    }
7075}
7076
7077impl MultiBufferRows<'_> {
7078    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7079        self.point = Point::new(row, 0);
7080        self.cursor.seek(&self.point);
7081    }
7082}
7083
7084impl Iterator for MultiBufferRows<'_> {
7085    type Item = RowInfo;
7086
7087    fn next(&mut self) -> Option<Self::Item> {
7088        if self.is_empty && self.point.row == 0 {
7089            self.point += Point::new(1, 0);
7090            return Some(RowInfo {
7091                buffer_id: None,
7092                buffer_row: Some(0),
7093                multibuffer_row: Some(MultiBufferRow(0)),
7094                diff_status: None,
7095            });
7096        }
7097
7098        let mut region = self.cursor.region()?;
7099        while self.point >= region.range.end {
7100            self.cursor.next();
7101            if let Some(next_region) = self.cursor.region() {
7102                region = next_region;
7103            } else {
7104                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7105                    let multibuffer_row = MultiBufferRow(self.point.row);
7106                    self.point += Point::new(1, 0);
7107                    let last_excerpt = self
7108                        .cursor
7109                        .excerpts
7110                        .item()
7111                        .or(self.cursor.excerpts.prev_item())?;
7112                    let last_row = last_excerpt
7113                        .range
7114                        .context
7115                        .end
7116                        .to_point(&last_excerpt.buffer)
7117                        .row;
7118                    return Some(RowInfo {
7119                        buffer_id: Some(last_excerpt.buffer_id),
7120                        buffer_row: Some(last_row),
7121                        multibuffer_row: Some(multibuffer_row),
7122                        diff_status: None,
7123                    });
7124                } else {
7125                    return None;
7126                }
7127            };
7128        }
7129
7130        let overshoot = self.point - region.range.start;
7131        let buffer_point = region.buffer_range.start + overshoot;
7132        let result = Some(RowInfo {
7133            buffer_id: Some(region.buffer.remote_id()),
7134            buffer_row: Some(buffer_point.row),
7135            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7136            diff_status: region
7137                .diff_hunk_status
7138                .filter(|_| self.point < region.range.end),
7139        });
7140        self.point += Point::new(1, 0);
7141        result
7142    }
7143}
7144
7145impl<'a> MultiBufferChunks<'a> {
7146    pub fn offset(&self) -> usize {
7147        self.range.start
7148    }
7149
7150    pub fn seek(&mut self, range: Range<usize>) {
7151        self.diff_transforms.seek(&range.end, Bias::Right, &());
7152        let mut excerpt_end = self.diff_transforms.start().1;
7153        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7154            let overshoot = range.end - self.diff_transforms.start().0;
7155            excerpt_end.value += overshoot;
7156        }
7157
7158        self.diff_transforms.seek(&range.start, Bias::Right, &());
7159        let mut excerpt_start = self.diff_transforms.start().1;
7160        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7161            let overshoot = range.start - self.diff_transforms.start().0;
7162            excerpt_start.value += overshoot;
7163        }
7164
7165        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7166        self.buffer_chunk.take();
7167        self.range = range;
7168    }
7169
7170    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7171        self.excerpt_offset_range = new_range.clone();
7172        self.excerpts.seek(&new_range.start, Bias::Right, &());
7173        if let Some(excerpt) = self.excerpts.item() {
7174            let excerpt_start = *self.excerpts.start();
7175            if let Some(excerpt_chunks) = self
7176                .excerpt_chunks
7177                .as_mut()
7178                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7179            {
7180                excerpt.seek_chunks(
7181                    excerpt_chunks,
7182                    (self.excerpt_offset_range.start - excerpt_start).value
7183                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7184                );
7185            } else {
7186                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7187                    (self.excerpt_offset_range.start - excerpt_start).value
7188                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7189                    self.language_aware,
7190                ));
7191            }
7192        } else {
7193            self.excerpt_chunks = None;
7194        }
7195    }
7196
7197    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7198        loop {
7199            if self.excerpt_offset_range.is_empty() {
7200                return None;
7201            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7202                self.excerpt_offset_range.start.value += chunk.text.len();
7203                return Some(chunk);
7204            } else {
7205                self.excerpts.next(&());
7206                let excerpt = self.excerpts.item()?;
7207                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7208                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7209                    self.language_aware,
7210                ));
7211            }
7212        }
7213    }
7214}
7215
7216impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7217    type Item = &'a str;
7218
7219    fn next(&mut self) -> Option<Self::Item> {
7220        let mut region = self.cursor.region()?;
7221        if self.offset == region.range.start {
7222            self.cursor.prev();
7223            region = self.cursor.region()?;
7224            let start_overshoot = self.start.saturating_sub(region.range.start);
7225            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7226                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7227            ));
7228        }
7229
7230        if self.offset == region.range.end && region.has_trailing_newline {
7231            self.offset -= 1;
7232            Some("\n")
7233        } else {
7234            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7235            self.offset -= chunk.len();
7236            Some(chunk)
7237        }
7238    }
7239}
7240
7241impl<'a> Iterator for MultiBufferChunks<'a> {
7242    type Item = Chunk<'a>;
7243
7244    fn next(&mut self) -> Option<Chunk<'a>> {
7245        if self.range.start >= self.range.end {
7246            return None;
7247        }
7248        if self.range.start == self.diff_transforms.end(&()).0 {
7249            self.diff_transforms.next(&());
7250        }
7251
7252        let diff_transform_start = self.diff_transforms.start().0;
7253        let diff_transform_end = self.diff_transforms.end(&()).0;
7254        debug_assert!(self.range.start < diff_transform_end);
7255
7256        let diff_transform = self.diff_transforms.item()?;
7257        match diff_transform {
7258            DiffTransform::BufferContent { .. } => {
7259                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7260                    chunk
7261                } else {
7262                    let chunk = self.next_excerpt_chunk().unwrap();
7263                    self.buffer_chunk.insert(chunk)
7264                };
7265
7266                let chunk_end = self.range.start + chunk.text.len();
7267                let diff_transform_end = diff_transform_end.min(self.range.end);
7268
7269                if diff_transform_end < chunk_end {
7270                    let (before, after) =
7271                        chunk.text.split_at(diff_transform_end - self.range.start);
7272                    self.range.start = diff_transform_end;
7273                    chunk.text = after;
7274                    Some(Chunk {
7275                        text: before,
7276                        ..chunk.clone()
7277                    })
7278                } else {
7279                    self.range.start = chunk_end;
7280                    self.buffer_chunk.take()
7281                }
7282            }
7283            DiffTransform::DeletedHunk {
7284                buffer_id,
7285                base_text_byte_range,
7286                has_trailing_newline,
7287                ..
7288            } => {
7289                let base_text_start =
7290                    base_text_byte_range.start + self.range.start - diff_transform_start;
7291                let base_text_end =
7292                    base_text_byte_range.start + self.range.end - diff_transform_start;
7293                let base_text_end = base_text_end.min(base_text_byte_range.end);
7294
7295                let mut chunks = if let Some((_, mut chunks)) = self
7296                    .diff_base_chunks
7297                    .take()
7298                    .filter(|(id, _)| id == buffer_id)
7299                {
7300                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7301                    {
7302                        chunks.seek(base_text_start..base_text_end);
7303                    }
7304                    chunks
7305                } else {
7306                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7307                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7308                };
7309
7310                let chunk = if let Some(chunk) = chunks.next() {
7311                    self.range.start += chunk.text.len();
7312                    self.diff_base_chunks = Some((*buffer_id, chunks));
7313                    chunk
7314                } else {
7315                    debug_assert!(has_trailing_newline);
7316                    self.range.start += "\n".len();
7317                    Chunk {
7318                        text: "\n",
7319                        ..Default::default()
7320                    }
7321                };
7322                Some(chunk)
7323            }
7324        }
7325    }
7326}
7327
7328impl MultiBufferBytes<'_> {
7329    fn consume(&mut self, len: usize) {
7330        self.range.start += len;
7331        self.chunk = &self.chunk[len..];
7332
7333        if !self.range.is_empty() && self.chunk.is_empty() {
7334            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7335                self.chunk = chunk;
7336            } else if self.has_trailing_newline {
7337                self.has_trailing_newline = false;
7338                self.chunk = b"\n";
7339            } else {
7340                self.cursor.next();
7341                if let Some(region) = self.cursor.region() {
7342                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7343                        region.buffer_range.start
7344                            ..(region.buffer_range.start + self.range.end - region.range.start)
7345                                .min(region.buffer_range.end),
7346                    );
7347                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7348                    self.excerpt_bytes = Some(excerpt_bytes);
7349                    self.has_trailing_newline =
7350                        region.has_trailing_newline && self.range.end >= region.range.end;
7351                    if self.chunk.is_empty() && self.has_trailing_newline {
7352                        self.has_trailing_newline = false;
7353                        self.chunk = b"\n";
7354                    }
7355                }
7356            }
7357        }
7358    }
7359}
7360
7361impl<'a> Iterator for MultiBufferBytes<'a> {
7362    type Item = &'a [u8];
7363
7364    fn next(&mut self) -> Option<Self::Item> {
7365        let chunk = self.chunk;
7366        if chunk.is_empty() {
7367            None
7368        } else {
7369            self.consume(chunk.len());
7370            Some(chunk)
7371        }
7372    }
7373}
7374
7375impl io::Read for MultiBufferBytes<'_> {
7376    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7377        let len = cmp::min(buf.len(), self.chunk.len());
7378        buf[..len].copy_from_slice(&self.chunk[..len]);
7379        if len > 0 {
7380            self.consume(len);
7381        }
7382        Ok(len)
7383    }
7384}
7385
7386impl io::Read for ReversedMultiBufferBytes<'_> {
7387    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7388        let len = cmp::min(buf.len(), self.chunk.len());
7389        buf[..len].copy_from_slice(&self.chunk[..len]);
7390        buf[..len].reverse();
7391        if len > 0 {
7392            self.range.end -= len;
7393            self.chunk = &self.chunk[..self.chunk.len() - len];
7394            if !self.range.is_empty() && self.chunk.is_empty() {
7395                if let Some(chunk) = self.chunks.next() {
7396                    self.chunk = chunk.as_bytes();
7397                }
7398            }
7399        }
7400        Ok(len)
7401    }
7402}
7403
7404impl<'a> Iterator for ExcerptChunks<'a> {
7405    type Item = Chunk<'a>;
7406
7407    fn next(&mut self) -> Option<Self::Item> {
7408        if let Some(chunk) = self.content_chunks.next() {
7409            return Some(chunk);
7410        }
7411
7412        if self.footer_height > 0 {
7413            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7414            self.footer_height = 0;
7415            return Some(Chunk {
7416                text,
7417                ..Default::default()
7418            });
7419        }
7420
7421        None
7422    }
7423}
7424
7425impl ToOffset for Point {
7426    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7427        snapshot.point_to_offset(*self)
7428    }
7429}
7430
7431impl ToOffset for usize {
7432    #[track_caller]
7433    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7434        assert!(*self <= snapshot.len(), "offset is out of range");
7435        *self
7436    }
7437}
7438
7439impl ToOffset for OffsetUtf16 {
7440    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7441        snapshot.offset_utf16_to_offset(*self)
7442    }
7443}
7444
7445impl ToOffset for PointUtf16 {
7446    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7447        snapshot.point_utf16_to_offset(*self)
7448    }
7449}
7450
7451impl ToOffsetUtf16 for OffsetUtf16 {
7452    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7453        *self
7454    }
7455}
7456
7457impl ToOffsetUtf16 for usize {
7458    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7459        snapshot.offset_to_offset_utf16(*self)
7460    }
7461}
7462
7463impl ToPoint for usize {
7464    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7465        snapshot.offset_to_point(*self)
7466    }
7467}
7468
7469impl ToPoint for Point {
7470    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7471        *self
7472    }
7473}
7474
7475impl ToPointUtf16 for usize {
7476    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7477        snapshot.offset_to_point_utf16(*self)
7478    }
7479}
7480
7481impl ToPointUtf16 for Point {
7482    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7483        snapshot.point_to_point_utf16(*self)
7484    }
7485}
7486
7487impl ToPointUtf16 for PointUtf16 {
7488    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7489        *self
7490    }
7491}
7492
7493impl From<ExcerptId> for EntityId {
7494    fn from(id: ExcerptId) -> Self {
7495        EntityId::from(id.0 as u64)
7496    }
7497}
7498
7499pub fn build_excerpt_ranges<T>(
7500    buffer: &BufferSnapshot,
7501    ranges: &[Range<T>],
7502    context_line_count: u32,
7503) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7504where
7505    T: text::ToPoint,
7506{
7507    let max_point = buffer.max_point();
7508    let mut range_counts = Vec::new();
7509    let mut excerpt_ranges = Vec::new();
7510    let mut range_iter = ranges
7511        .iter()
7512        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7513        .peekable();
7514    while let Some(range) = range_iter.next() {
7515        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7516        let row = (range.end.row + context_line_count).min(max_point.row);
7517        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7518
7519        let mut ranges_in_excerpt = 1;
7520
7521        while let Some(next_range) = range_iter.peek() {
7522            if next_range.start.row <= excerpt_end.row + context_line_count {
7523                let row = (next_range.end.row + context_line_count).min(max_point.row);
7524                excerpt_end = Point::new(row, buffer.line_len(row));
7525
7526                ranges_in_excerpt += 1;
7527                range_iter.next();
7528            } else {
7529                break;
7530            }
7531        }
7532
7533        excerpt_ranges.push(ExcerptRange {
7534            context: excerpt_start..excerpt_end,
7535            primary: Some(range),
7536        });
7537        range_counts.push(ranges_in_excerpt);
7538    }
7539
7540    (excerpt_ranges, range_counts)
7541}