multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{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 point = point.to_point(&snapshot);
2011        let mut cursor = snapshot.cursor::<Point>();
2012        cursor.seek(&point);
2013
2014        cursor.region().and_then(|region| {
2015            if !region.is_main_buffer {
2016                return None;
2017            }
2018
2019            let overshoot = point - region.range.start;
2020            let buffer_point = region.buffer_range.start + overshoot;
2021            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
2022                .buffer
2023                .clone();
2024            Some((buffer, buffer_point, region.excerpt.id))
2025        })
2026    }
2027
2028    pub fn buffer_point_to_anchor(
2029        &self,
2030        buffer: &Entity<Buffer>,
2031        point: Point,
2032        cx: &App,
2033    ) -> Option<Anchor> {
2034        let mut found = None;
2035        let snapshot = buffer.read(cx).snapshot();
2036        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2037            let start = range.context.start.to_point(&snapshot);
2038            let end = range.context.end.to_point(&snapshot);
2039            if start <= point && point < end {
2040                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2041                break;
2042            }
2043            if point < start {
2044                found = Some((start, excerpt_id));
2045            }
2046            if point > end {
2047                found = Some((end, excerpt_id));
2048            }
2049        }
2050
2051        found.map(|(point, excerpt_id)| {
2052            let text_anchor = snapshot.anchor_after(point);
2053            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2054        })
2055    }
2056
2057    pub fn remove_excerpts(
2058        &mut self,
2059        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2060        cx: &mut Context<Self>,
2061    ) {
2062        self.sync(cx);
2063        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2064        if ids.is_empty() {
2065            return;
2066        }
2067
2068        let mut buffers = self.buffers.borrow_mut();
2069        let mut snapshot = self.snapshot.borrow_mut();
2070        let mut new_excerpts = SumTree::default();
2071        let mut cursor = snapshot
2072            .excerpts
2073            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2074        let mut edits = Vec::new();
2075        let mut excerpt_ids = ids.iter().copied().peekable();
2076        let mut removed_buffer_ids = Vec::new();
2077
2078        while let Some(excerpt_id) = excerpt_ids.next() {
2079            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2080            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2081            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2082
2083            if let Some(mut excerpt) = cursor.item() {
2084                if excerpt.id != excerpt_id {
2085                    continue;
2086                }
2087                let mut old_start = cursor.start().1;
2088
2089                // Skip over the removed excerpt.
2090                'remove_excerpts: loop {
2091                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2092                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2093                        if buffer_state.excerpts.is_empty() {
2094                            log::debug!(
2095                                "removing buffer and diff for buffer {}",
2096                                excerpt.buffer_id
2097                            );
2098                            buffers.remove(&excerpt.buffer_id);
2099                            removed_buffer_ids.push(excerpt.buffer_id);
2100                        }
2101                    }
2102                    cursor.next(&());
2103
2104                    // Skip over any subsequent excerpts that are also removed.
2105                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2106                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2107                        if let Some(next_excerpt) = cursor.item() {
2108                            if next_excerpt.locator == *next_locator {
2109                                excerpt_ids.next();
2110                                excerpt = next_excerpt;
2111                                continue 'remove_excerpts;
2112                            }
2113                        }
2114                    }
2115
2116                    break;
2117                }
2118
2119                // When removing the last excerpt, remove the trailing newline from
2120                // the previous excerpt.
2121                if cursor.item().is_none() && old_start.value > 0 {
2122                    old_start.value -= 1;
2123                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2124                }
2125
2126                // Push an edit for the removal of this run of excerpts.
2127                let old_end = cursor.start().1;
2128                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2129                edits.push(Edit {
2130                    old: old_start..old_end,
2131                    new: new_start..new_start,
2132                });
2133            }
2134        }
2135        let suffix = cursor.suffix(&());
2136        let changed_trailing_excerpt = suffix.is_empty();
2137        new_excerpts.append(suffix, &());
2138        drop(cursor);
2139        snapshot.excerpts = new_excerpts;
2140        for buffer_id in removed_buffer_ids {
2141            self.diffs.remove(&buffer_id);
2142            snapshot.diffs.remove(&buffer_id);
2143        }
2144
2145        if changed_trailing_excerpt {
2146            snapshot.trailing_excerpt_update_count += 1;
2147        }
2148
2149        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2150        cx.emit(Event::Edited {
2151            singleton_buffer_edited: false,
2152            edited_buffer: None,
2153        });
2154        cx.emit(Event::ExcerptsRemoved { ids });
2155        cx.notify();
2156    }
2157
2158    pub fn wait_for_anchors<'a>(
2159        &self,
2160        anchors: impl 'a + Iterator<Item = Anchor>,
2161        cx: &mut Context<Self>,
2162    ) -> impl 'static + Future<Output = Result<()>> {
2163        let borrow = self.buffers.borrow();
2164        let mut error = None;
2165        let mut futures = Vec::new();
2166        for anchor in anchors {
2167            if let Some(buffer_id) = anchor.buffer_id {
2168                if let Some(buffer) = borrow.get(&buffer_id) {
2169                    buffer.buffer.update(cx, |buffer, _| {
2170                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2171                    });
2172                } else {
2173                    error = Some(anyhow!(
2174                        "buffer {buffer_id} is not part of this multi-buffer"
2175                    ));
2176                    break;
2177                }
2178            }
2179        }
2180        async move {
2181            if let Some(error) = error {
2182                Err(error)?;
2183            }
2184            for future in futures {
2185                future.await?;
2186            }
2187            Ok(())
2188        }
2189    }
2190
2191    pub fn text_anchor_for_position<T: ToOffset>(
2192        &self,
2193        position: T,
2194        cx: &App,
2195    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2196        let snapshot = self.read(cx);
2197        let anchor = snapshot.anchor_before(position);
2198        let buffer = self
2199            .buffers
2200            .borrow()
2201            .get(&anchor.buffer_id?)?
2202            .buffer
2203            .clone();
2204        Some((buffer, anchor.text_anchor))
2205    }
2206
2207    fn on_buffer_event(
2208        &mut self,
2209        buffer: Entity<Buffer>,
2210        event: &language::BufferEvent,
2211        cx: &mut Context<Self>,
2212    ) {
2213        cx.emit(match event {
2214            language::BufferEvent::Edited => Event::Edited {
2215                singleton_buffer_edited: true,
2216                edited_buffer: Some(buffer.clone()),
2217            },
2218            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2219            language::BufferEvent::Saved => Event::Saved,
2220            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2221            language::BufferEvent::Reloaded => Event::Reloaded,
2222            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2223            language::BufferEvent::LanguageChanged => {
2224                Event::LanguageChanged(buffer.read(cx).remote_id())
2225            }
2226            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2227            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2228            language::BufferEvent::Closed => Event::Closed,
2229            language::BufferEvent::Discarded => Event::Discarded,
2230            language::BufferEvent::CapabilityChanged => {
2231                self.capability = buffer.read(cx).capability();
2232                Event::CapabilityChanged
2233            }
2234            language::BufferEvent::Operation { .. } => return,
2235        });
2236    }
2237
2238    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2239        self.sync(cx);
2240        let mut snapshot = self.snapshot.borrow_mut();
2241        let diff = diff.read(cx);
2242        let buffer_id = diff.buffer_id;
2243        let diff = diff.snapshot(cx);
2244        snapshot.diffs.insert(buffer_id, diff);
2245    }
2246
2247    fn buffer_diff_changed(
2248        &mut self,
2249        diff: Entity<BufferDiff>,
2250        range: Range<text::Anchor>,
2251        cx: &mut Context<Self>,
2252    ) {
2253        self.sync(cx);
2254        self.buffer_changed_since_sync.replace(true);
2255
2256        let diff = diff.read(cx);
2257        let buffer_id = diff.buffer_id;
2258        let buffers = self.buffers.borrow();
2259        let Some(buffer_state) = buffers.get(&buffer_id) else {
2260            return;
2261        };
2262
2263        let buffer = buffer_state.buffer.read(cx);
2264        let diff_change_range = range.to_offset(buffer);
2265
2266        let new_diff = diff.snapshot(cx);
2267        let mut snapshot = self.snapshot.borrow_mut();
2268        let base_text_changed = snapshot
2269            .diffs
2270            .get(&buffer_id)
2271            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2272
2273        snapshot.diffs.insert(buffer_id, new_diff);
2274
2275        let mut excerpt_edits = Vec::new();
2276        for locator in &buffer_state.excerpts {
2277            let mut cursor = snapshot
2278                .excerpts
2279                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2280            cursor.seek_forward(&Some(locator), Bias::Left, &());
2281            if let Some(excerpt) = cursor.item() {
2282                if excerpt.locator == *locator {
2283                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2284                    if diff_change_range.end < excerpt_buffer_range.start
2285                        || diff_change_range.start > excerpt_buffer_range.end
2286                    {
2287                        continue;
2288                    }
2289                    let excerpt_start = cursor.start().1;
2290                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2291                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2292                        diff_change_range
2293                            .start
2294                            .saturating_sub(excerpt_buffer_range.start),
2295                    );
2296                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2297                        diff_change_range
2298                            .end
2299                            .saturating_sub(excerpt_buffer_range.start),
2300                    );
2301                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2302                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2303                    excerpt_edits.push(Edit {
2304                        old: edit_start..edit_end,
2305                        new: edit_start..edit_end,
2306                    });
2307                }
2308            }
2309        }
2310
2311        self.sync_diff_transforms(
2312            &mut snapshot,
2313            excerpt_edits,
2314            DiffChangeKind::DiffUpdated {
2315                base_changed: base_text_changed,
2316            },
2317        );
2318        cx.emit(Event::Edited {
2319            singleton_buffer_edited: false,
2320            edited_buffer: None,
2321        });
2322    }
2323
2324    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2325        self.buffers
2326            .borrow()
2327            .values()
2328            .map(|state| state.buffer.clone())
2329            .collect()
2330    }
2331
2332    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2333        self.buffers
2334            .borrow()
2335            .get(&buffer_id)
2336            .map(|state| state.buffer.clone())
2337    }
2338
2339    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2340        self.point_to_buffer_offset(point, cx)
2341            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2342    }
2343
2344    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2345        let buffer_id = self
2346            .snapshot
2347            .borrow()
2348            .excerpts
2349            .first()
2350            .map(|excerpt| excerpt.buffer.remote_id());
2351        buffer_id
2352            .and_then(|buffer_id| self.buffer(buffer_id))
2353            .map(|buffer| {
2354                let buffer = buffer.read(cx);
2355                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2356            })
2357            .unwrap_or_else(move || self.language_settings_at(0, cx))
2358    }
2359
2360    pub fn language_settings_at<'a, T: ToOffset>(
2361        &'a self,
2362        point: T,
2363        cx: &'a App,
2364    ) -> Cow<'a, LanguageSettings> {
2365        let mut language = None;
2366        let mut file = None;
2367        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2368            let buffer = buffer.read(cx);
2369            language = buffer.language_at(offset);
2370            file = buffer.file();
2371        }
2372        language_settings(language.map(|l| l.name()), file, cx)
2373    }
2374
2375    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2376        self.buffers
2377            .borrow()
2378            .values()
2379            .for_each(|state| f(&state.buffer))
2380    }
2381
2382    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2383        if let Some(title) = self.title.as_ref() {
2384            return title.into();
2385        }
2386
2387        if let Some(buffer) = self.as_singleton() {
2388            if let Some(file) = buffer.read(cx).file() {
2389                return file.file_name(cx).to_string_lossy();
2390            }
2391        }
2392
2393        "untitled".into()
2394    }
2395
2396    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2397        self.title = Some(title);
2398        cx.notify();
2399    }
2400
2401    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2402    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2403        for buffer_state in self.buffers.borrow().values() {
2404            buffer_state
2405                .buffer
2406                .update(cx, |buffer, _cx| buffer.refresh_preview());
2407        }
2408    }
2409
2410    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2411    pub fn preserve_preview(&self, cx: &App) -> bool {
2412        self.buffers
2413            .borrow()
2414            .values()
2415            .all(|state| state.buffer.read(cx).preserve_preview())
2416    }
2417
2418    #[cfg(any(test, feature = "test-support"))]
2419    pub fn is_parsing(&self, cx: &App) -> bool {
2420        self.as_singleton().unwrap().read(cx).is_parsing()
2421    }
2422
2423    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2424        let buffer_id = diff.read(cx).buffer_id;
2425        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2426        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2427    }
2428
2429    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2430        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2431    }
2432
2433    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2434        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2435    }
2436
2437    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2438        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2439    }
2440
2441    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2442        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2443        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2444    }
2445
2446    pub fn all_diff_hunks_expanded(&self) -> bool {
2447        self.snapshot.borrow().all_diff_hunks_expanded
2448    }
2449
2450    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2451        self.read(cx)
2452            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2453            .nth(1)
2454            .is_some()
2455    }
2456
2457    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2458        let snapshot = self.read(cx);
2459        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2460        let offset_range = range.to_offset(&snapshot);
2461        cursor.seek(&offset_range.start, Bias::Left, &());
2462        while let Some(item) = cursor.item() {
2463            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2464                break;
2465            }
2466            if item.hunk_info().is_some() {
2467                return true;
2468            }
2469            cursor.next(&());
2470        }
2471        false
2472    }
2473
2474    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2475        let snapshot = self.read(cx);
2476        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2477        for range in ranges {
2478            let range = range.to_point(&snapshot);
2479            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2480            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2481            let start = start.saturating_sub(1);
2482            let end = snapshot.len().min(end + 1);
2483            cursor.seek(&start, Bias::Right, &());
2484            while let Some(item) = cursor.item() {
2485                if *cursor.start() >= end {
2486                    break;
2487                }
2488                if item.hunk_info().is_some() {
2489                    return true;
2490                }
2491                cursor.next(&());
2492            }
2493        }
2494        false
2495    }
2496
2497    pub fn expand_or_collapse_diff_hunks_inner(
2498        &mut self,
2499        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2500        expand: bool,
2501        cx: &mut Context<Self>,
2502    ) {
2503        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2504            return;
2505        }
2506        self.sync(cx);
2507        let mut snapshot = self.snapshot.borrow_mut();
2508        let mut excerpt_edits = Vec::new();
2509        for (range, end_excerpt_id) in ranges {
2510            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2511                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2512                    continue;
2513                }
2514                let start = Anchor::in_buffer(
2515                    diff_hunk.excerpt_id,
2516                    diff_hunk.buffer_id,
2517                    diff_hunk.buffer_range.start,
2518                );
2519                let end = Anchor::in_buffer(
2520                    diff_hunk.excerpt_id,
2521                    diff_hunk.buffer_id,
2522                    diff_hunk.buffer_range.end,
2523                );
2524                let start = snapshot.excerpt_offset_for_anchor(&start);
2525                let end = snapshot.excerpt_offset_for_anchor(&end);
2526                excerpt_edits.push(text::Edit {
2527                    old: start..end,
2528                    new: start..end,
2529                });
2530            }
2531        }
2532
2533        self.sync_diff_transforms(
2534            &mut snapshot,
2535            excerpt_edits,
2536            DiffChangeKind::ExpandOrCollapseHunks { expand },
2537        );
2538        cx.emit(Event::DiffHunksToggled);
2539        cx.emit(Event::Edited {
2540            singleton_buffer_edited: false,
2541            edited_buffer: None,
2542        });
2543    }
2544
2545    pub fn expand_or_collapse_diff_hunks(
2546        &mut self,
2547        ranges: Vec<Range<Anchor>>,
2548        expand: bool,
2549        cx: &mut Context<Self>,
2550    ) {
2551        let snapshot = self.snapshot.borrow().clone();
2552        let ranges = ranges.iter().map(move |range| {
2553            let end_excerpt_id = range.end.excerpt_id;
2554            let range = range.to_point(&snapshot);
2555            let mut peek_end = range.end;
2556            if range.end.row < snapshot.max_row().0 {
2557                peek_end = Point::new(range.end.row + 1, 0);
2558            };
2559            (range.start..peek_end, end_excerpt_id)
2560        });
2561        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2562    }
2563
2564    pub fn resize_excerpt(
2565        &mut self,
2566        id: ExcerptId,
2567        range: Range<text::Anchor>,
2568        cx: &mut Context<Self>,
2569    ) {
2570        self.sync(cx);
2571
2572        let mut snapshot = self.snapshot.borrow_mut();
2573        let locator = snapshot.excerpt_locator_for_id(id);
2574        let mut new_excerpts = SumTree::default();
2575        let mut cursor = snapshot
2576            .excerpts
2577            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2578        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2579
2580        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2581        new_excerpts.append(prefix, &());
2582
2583        let mut excerpt = cursor.item().unwrap().clone();
2584        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2585
2586        excerpt.range.context.start = range.start;
2587        excerpt.range.context.end = range.end;
2588        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2589
2590        excerpt.text_summary = excerpt
2591            .buffer
2592            .text_summary_for_range(excerpt.range.context.clone());
2593
2594        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2595        let old_start_offset = cursor.start().1;
2596        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2597        let edit = Edit {
2598            old: old_start_offset..old_start_offset + old_text_len,
2599            new: new_start_offset..new_start_offset + new_text_len,
2600        };
2601
2602        if let Some(last_edit) = edits.last_mut() {
2603            if last_edit.old.end == edit.old.start {
2604                last_edit.old.end = edit.old.end;
2605                last_edit.new.end = edit.new.end;
2606            } else {
2607                edits.push(edit);
2608            }
2609        } else {
2610            edits.push(edit);
2611        }
2612
2613        new_excerpts.push(excerpt, &());
2614
2615        cursor.next(&());
2616
2617        new_excerpts.append(cursor.suffix(&()), &());
2618
2619        drop(cursor);
2620        snapshot.excerpts = new_excerpts;
2621
2622        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2623        cx.emit(Event::Edited {
2624            singleton_buffer_edited: false,
2625            edited_buffer: None,
2626        });
2627        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2628        cx.notify();
2629    }
2630
2631    pub fn expand_excerpts(
2632        &mut self,
2633        ids: impl IntoIterator<Item = ExcerptId>,
2634        line_count: u32,
2635        direction: ExpandExcerptDirection,
2636        cx: &mut Context<Self>,
2637    ) {
2638        if line_count == 0 {
2639            return;
2640        }
2641        self.sync(cx);
2642        let mut snapshot = self.snapshot.borrow_mut();
2643
2644        let ids = ids.into_iter().collect::<Vec<_>>();
2645        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2646        let mut new_excerpts = SumTree::default();
2647        let mut cursor = snapshot
2648            .excerpts
2649            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2650        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2651
2652        for locator in &locators {
2653            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2654            new_excerpts.append(prefix, &());
2655
2656            let mut excerpt = cursor.item().unwrap().clone();
2657            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2658
2659            let up_line_count = if direction.should_expand_up() {
2660                line_count
2661            } else {
2662                0
2663            };
2664
2665            let start_row = excerpt
2666                .range
2667                .context
2668                .start
2669                .to_point(&excerpt.buffer)
2670                .row
2671                .saturating_sub(up_line_count);
2672            let start_point = Point::new(start_row, 0);
2673            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2674
2675            let down_line_count = if direction.should_expand_down() {
2676                line_count
2677            } else {
2678                0
2679            };
2680
2681            let mut end_point = excerpt.buffer.clip_point(
2682                excerpt.range.context.end.to_point(&excerpt.buffer)
2683                    + Point::new(down_line_count, 0),
2684                Bias::Left,
2685            );
2686            end_point.column = excerpt.buffer.line_len(end_point.row);
2687            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2688            excerpt.max_buffer_row = end_point.row;
2689
2690            excerpt.text_summary = excerpt
2691                .buffer
2692                .text_summary_for_range(excerpt.range.context.clone());
2693
2694            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2695            let old_start_offset = cursor.start().1;
2696            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2697            let edit = Edit {
2698                old: old_start_offset..old_start_offset + old_text_len,
2699                new: new_start_offset..new_start_offset + new_text_len,
2700            };
2701
2702            if let Some(last_edit) = edits.last_mut() {
2703                if last_edit.old.end == edit.old.start {
2704                    last_edit.old.end = edit.old.end;
2705                    last_edit.new.end = edit.new.end;
2706                } else {
2707                    edits.push(edit);
2708                }
2709            } else {
2710                edits.push(edit);
2711            }
2712
2713            new_excerpts.push(excerpt, &());
2714
2715            cursor.next(&());
2716        }
2717
2718        new_excerpts.append(cursor.suffix(&()), &());
2719
2720        drop(cursor);
2721        snapshot.excerpts = new_excerpts;
2722
2723        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2724        cx.emit(Event::Edited {
2725            singleton_buffer_edited: false,
2726            edited_buffer: None,
2727        });
2728        cx.emit(Event::ExcerptsExpanded { ids });
2729        cx.notify();
2730    }
2731
2732    fn sync(&self, cx: &App) {
2733        let changed = self.buffer_changed_since_sync.replace(false);
2734        if !changed {
2735            return;
2736        }
2737
2738        let mut snapshot = self.snapshot.borrow_mut();
2739        let mut excerpts_to_edit = Vec::new();
2740        let mut non_text_state_updated = false;
2741        let mut is_dirty = false;
2742        let mut has_deleted_file = false;
2743        let mut has_conflict = false;
2744        let mut edited = false;
2745        let mut buffers = self.buffers.borrow_mut();
2746        for buffer_state in buffers.values_mut() {
2747            let buffer = buffer_state.buffer.read(cx);
2748            let version = buffer.version();
2749            let non_text_state_update_count = buffer.non_text_state_update_count();
2750
2751            let buffer_edited = version.changed_since(&buffer_state.last_version);
2752            let buffer_non_text_state_updated =
2753                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2754            if buffer_edited || buffer_non_text_state_updated {
2755                buffer_state.last_version = version;
2756                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2757                excerpts_to_edit.extend(
2758                    buffer_state
2759                        .excerpts
2760                        .iter()
2761                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2762                );
2763            }
2764
2765            edited |= buffer_edited;
2766            non_text_state_updated |= buffer_non_text_state_updated;
2767            is_dirty |= buffer.is_dirty();
2768            has_deleted_file |= buffer
2769                .file()
2770                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2771            has_conflict |= buffer.has_conflict();
2772        }
2773        if edited {
2774            snapshot.edit_count += 1;
2775        }
2776        if non_text_state_updated {
2777            snapshot.non_text_state_update_count += 1;
2778        }
2779        snapshot.is_dirty = is_dirty;
2780        snapshot.has_deleted_file = has_deleted_file;
2781        snapshot.has_conflict = has_conflict;
2782
2783        for (id, diff) in self.diffs.iter() {
2784            if snapshot.diffs.get(&id).is_none() {
2785                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2786            }
2787        }
2788
2789        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2790
2791        let mut edits = Vec::new();
2792        let mut new_excerpts = SumTree::default();
2793        let mut cursor = snapshot
2794            .excerpts
2795            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2796
2797        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2798            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2799            let old_excerpt = cursor.item().unwrap();
2800            let buffer = buffer.read(cx);
2801            let buffer_id = buffer.remote_id();
2802
2803            let mut new_excerpt;
2804            if buffer_edited {
2805                edits.extend(
2806                    buffer
2807                        .edits_since_in_range::<usize>(
2808                            old_excerpt.buffer.version(),
2809                            old_excerpt.range.context.clone(),
2810                        )
2811                        .map(|edit| {
2812                            let excerpt_old_start = cursor.start().1;
2813                            let excerpt_new_start =
2814                                ExcerptOffset::new(new_excerpts.summary().text.len);
2815                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2816                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2817                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2818                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2819                            Edit {
2820                                old: old_start..old_end,
2821                                new: new_start..new_end,
2822                            }
2823                        }),
2824                );
2825
2826                new_excerpt = Excerpt::new(
2827                    old_excerpt.id,
2828                    locator.clone(),
2829                    buffer_id,
2830                    buffer.snapshot(),
2831                    old_excerpt.range.clone(),
2832                    old_excerpt.has_trailing_newline,
2833                );
2834            } else {
2835                new_excerpt = old_excerpt.clone();
2836                new_excerpt.buffer = buffer.snapshot();
2837            }
2838
2839            new_excerpts.push(new_excerpt, &());
2840            cursor.next(&());
2841        }
2842        new_excerpts.append(cursor.suffix(&()), &());
2843
2844        drop(cursor);
2845        snapshot.excerpts = new_excerpts;
2846
2847        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2848    }
2849
2850    fn sync_diff_transforms(
2851        &self,
2852        snapshot: &mut MultiBufferSnapshot,
2853        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2854        change_kind: DiffChangeKind,
2855    ) {
2856        if excerpt_edits.is_empty() {
2857            return;
2858        }
2859
2860        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2861        let mut old_diff_transforms = snapshot
2862            .diff_transforms
2863            .cursor::<(ExcerptOffset, usize)>(&());
2864        let mut new_diff_transforms = SumTree::default();
2865        let mut old_expanded_hunks = HashSet::default();
2866        let mut output_edits = Vec::new();
2867        let mut output_delta = 0_isize;
2868        let mut at_transform_boundary = true;
2869        let mut end_of_current_insert = None;
2870
2871        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2872        while let Some(edit) = excerpt_edits.next() {
2873            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2874            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2875                excerpts.prev(&());
2876            }
2877
2878            // Keep any transforms that are before the edit.
2879            if at_transform_boundary {
2880                at_transform_boundary = false;
2881                let transforms_before_edit =
2882                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2883                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2884                if let Some(transform) = old_diff_transforms.item() {
2885                    if old_diff_transforms.end(&()).0 == edit.old.start
2886                        && old_diff_transforms.start().0 < edit.old.start
2887                    {
2888                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2889                        old_diff_transforms.next(&());
2890                    }
2891                }
2892            }
2893
2894            // Compute the start of the edit in output coordinates.
2895            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2896            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2897            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2898
2899            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2900                &edit,
2901                &mut excerpts,
2902                &mut old_diff_transforms,
2903                &mut new_diff_transforms,
2904                &mut end_of_current_insert,
2905                &mut old_expanded_hunks,
2906                &snapshot,
2907                change_kind,
2908            );
2909
2910            // Compute the end of the edit in output coordinates.
2911            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2912            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2913            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2914            let edit_new_end =
2915                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2916            let output_edit = Edit {
2917                old: edit_old_start..edit_old_end,
2918                new: edit_new_start..edit_new_end,
2919            };
2920
2921            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2922            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2923            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2924                output_edits.push(output_edit);
2925            }
2926
2927            // If this is the last edit that intersects the current diff transform,
2928            // then recreate the content up to the end of this transform, to prepare
2929            // for reusing additional slices of the old transforms.
2930            if excerpt_edits.peek().map_or(true, |next_edit| {
2931                next_edit.old.start >= old_diff_transforms.end(&()).0
2932            }) {
2933                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2934                    && match old_diff_transforms.item() {
2935                        Some(DiffTransform::BufferContent {
2936                            inserted_hunk_info: Some(hunk),
2937                            ..
2938                        }) => excerpts.item().is_some_and(|excerpt| {
2939                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2940                        }),
2941                        _ => true,
2942                    };
2943
2944                let mut excerpt_offset = edit.new.end;
2945                if !keep_next_old_transform {
2946                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2947                    old_diff_transforms.next(&());
2948                }
2949
2950                old_expanded_hunks.clear();
2951                self.push_buffer_content_transform(
2952                    &snapshot,
2953                    &mut new_diff_transforms,
2954                    excerpt_offset,
2955                    end_of_current_insert,
2956                );
2957                at_transform_boundary = true;
2958            }
2959        }
2960
2961        // Keep any transforms that are after the last edit.
2962        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2963
2964        // Ensure there's always at least one buffer content transform.
2965        if new_diff_transforms.is_empty() {
2966            new_diff_transforms.push(
2967                DiffTransform::BufferContent {
2968                    summary: Default::default(),
2969                    inserted_hunk_info: None,
2970                },
2971                &(),
2972            );
2973        }
2974
2975        self.subscriptions.publish(output_edits);
2976        drop(old_diff_transforms);
2977        drop(excerpts);
2978        snapshot.diff_transforms = new_diff_transforms;
2979        snapshot.edit_count += 1;
2980
2981        #[cfg(any(test, feature = "test-support"))]
2982        snapshot.check_invariants();
2983    }
2984
2985    #[allow(clippy::too_many_arguments)]
2986    fn recompute_diff_transforms_for_edit(
2987        &self,
2988        edit: &Edit<TypedOffset<Excerpt>>,
2989        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2990        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2991        new_diff_transforms: &mut SumTree<DiffTransform>,
2992        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2993        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2994        snapshot: &MultiBufferSnapshot,
2995        change_kind: DiffChangeKind,
2996    ) -> bool {
2997        log::trace!(
2998            "recomputing diff transform for edit {:?} => {:?}",
2999            edit.old.start.value..edit.old.end.value,
3000            edit.new.start.value..edit.new.end.value
3001        );
3002
3003        // Record which hunks were previously expanded.
3004        while let Some(item) = old_diff_transforms.item() {
3005            if let Some(hunk_info) = item.hunk_info() {
3006                log::trace!(
3007                    "previously expanded hunk at {}",
3008                    old_diff_transforms.start().0
3009                );
3010                old_expanded_hunks.insert(hunk_info);
3011            }
3012            if old_diff_transforms.end(&()).0 > edit.old.end {
3013                break;
3014            }
3015            old_diff_transforms.next(&());
3016        }
3017
3018        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3019        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3020        if old_expanded_hunks.is_empty()
3021            && change_kind == DiffChangeKind::BufferEdited
3022            && !all_diff_hunks_expanded
3023        {
3024            return false;
3025        }
3026
3027        // Visit each excerpt that intersects the edit.
3028        let mut did_expand_hunks = false;
3029        while let Some(excerpt) = excerpts.item() {
3030            // Recompute the expanded hunks in the portion of the excerpt that
3031            // intersects the edit.
3032            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3033                let buffer = &excerpt.buffer;
3034                let excerpt_start = *excerpts.start();
3035                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3036                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3037                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3038                let edit_buffer_start =
3039                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3040                let edit_buffer_end =
3041                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3042                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3043                let edit_anchor_range =
3044                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3045
3046                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3047                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3048                        continue;
3049                    }
3050
3051                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3052                    if hunk_buffer_range.start < excerpt_buffer_start {
3053                        log::trace!("skipping hunk that starts before excerpt");
3054                        continue;
3055                    }
3056
3057                    let hunk_info = DiffTransformHunkInfo {
3058                        excerpt_id: excerpt.id,
3059                        hunk_start_anchor: hunk.buffer_range.start,
3060                        hunk_secondary_status: hunk.secondary_status,
3061                    };
3062
3063                    let hunk_excerpt_start = excerpt_start
3064                        + ExcerptOffset::new(
3065                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3066                        );
3067                    let hunk_excerpt_end = excerpt_end.min(
3068                        excerpt_start
3069                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3070                    );
3071
3072                    self.push_buffer_content_transform(
3073                        snapshot,
3074                        new_diff_transforms,
3075                        hunk_excerpt_start,
3076                        *end_of_current_insert,
3077                    );
3078
3079                    // For every existing hunk, determine if it was previously expanded
3080                    // and if it should currently be expanded.
3081                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3082                    let should_expand_hunk = match &change_kind {
3083                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3084                            was_previously_expanded || all_diff_hunks_expanded
3085                        }
3086                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3087                            let intersects = hunk_buffer_range.is_empty()
3088                                || hunk_buffer_range.end > edit_buffer_start;
3089                            if *expand {
3090                                intersects || was_previously_expanded || all_diff_hunks_expanded
3091                            } else {
3092                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3093                            }
3094                        }
3095                        _ => was_previously_expanded || all_diff_hunks_expanded,
3096                    };
3097
3098                    if should_expand_hunk {
3099                        did_expand_hunks = true;
3100                        log::trace!(
3101                            "expanding hunk {:?}, excerpt:{:?}",
3102                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3103                            excerpt.id
3104                        );
3105
3106                        if !hunk.diff_base_byte_range.is_empty()
3107                            && hunk_buffer_range.start >= edit_buffer_start
3108                            && hunk_buffer_range.start <= excerpt_buffer_end
3109                        {
3110                            let base_text = diff.base_text();
3111                            let mut text_cursor =
3112                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3113                            let mut base_text_summary =
3114                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3115
3116                            let mut has_trailing_newline = false;
3117                            if base_text_summary.last_line_chars > 0 {
3118                                base_text_summary += TextSummary::newline();
3119                                has_trailing_newline = true;
3120                            }
3121
3122                            new_diff_transforms.push(
3123                                DiffTransform::DeletedHunk {
3124                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3125                                    summary: base_text_summary,
3126                                    buffer_id: excerpt.buffer_id,
3127                                    hunk_info,
3128                                    has_trailing_newline,
3129                                },
3130                                &(),
3131                            );
3132                        }
3133
3134                        if !hunk_buffer_range.is_empty() {
3135                            *end_of_current_insert =
3136                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3137                        }
3138                    }
3139                }
3140            }
3141
3142            if excerpts.end(&()) <= edit.new.end {
3143                excerpts.next(&());
3144            } else {
3145                break;
3146            }
3147        }
3148
3149        did_expand_hunks || !old_expanded_hunks.is_empty()
3150    }
3151
3152    fn append_diff_transforms(
3153        &self,
3154        new_transforms: &mut SumTree<DiffTransform>,
3155        subtree: SumTree<DiffTransform>,
3156    ) {
3157        if let Some(DiffTransform::BufferContent {
3158            inserted_hunk_info,
3159            summary,
3160        }) = subtree.first()
3161        {
3162            if self.extend_last_buffer_content_transform(
3163                new_transforms,
3164                *inserted_hunk_info,
3165                *summary,
3166            ) {
3167                let mut cursor = subtree.cursor::<()>(&());
3168                cursor.next(&());
3169                cursor.next(&());
3170                new_transforms.append(cursor.suffix(&()), &());
3171                return;
3172            }
3173        }
3174        new_transforms.append(subtree, &());
3175    }
3176
3177    fn push_diff_transform(
3178        &self,
3179        new_transforms: &mut SumTree<DiffTransform>,
3180        transform: DiffTransform,
3181    ) {
3182        if let DiffTransform::BufferContent {
3183            inserted_hunk_info: inserted_hunk_anchor,
3184            summary,
3185        } = transform
3186        {
3187            if self.extend_last_buffer_content_transform(
3188                new_transforms,
3189                inserted_hunk_anchor,
3190                summary,
3191            ) {
3192                return;
3193            }
3194        }
3195        new_transforms.push(transform, &());
3196    }
3197
3198    fn push_buffer_content_transform(
3199        &self,
3200        old_snapshot: &MultiBufferSnapshot,
3201        new_transforms: &mut SumTree<DiffTransform>,
3202        end_offset: ExcerptOffset,
3203        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3204    ) {
3205        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3206            (end_offset.min(insertion_end_offset), Some(hunk_info))
3207        });
3208        let unchanged_region = [(end_offset, None)];
3209
3210        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3211        {
3212            let start_offset = new_transforms.summary().excerpt_len();
3213            if end_offset <= start_offset {
3214                continue;
3215            }
3216            let summary_to_add = old_snapshot
3217                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3218
3219            if !self.extend_last_buffer_content_transform(
3220                new_transforms,
3221                inserted_hunk_info,
3222                summary_to_add,
3223            ) {
3224                new_transforms.push(
3225                    DiffTransform::BufferContent {
3226                        summary: summary_to_add,
3227                        inserted_hunk_info,
3228                    },
3229                    &(),
3230                )
3231            }
3232        }
3233    }
3234
3235    fn extend_last_buffer_content_transform(
3236        &self,
3237        new_transforms: &mut SumTree<DiffTransform>,
3238        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3239        summary_to_add: TextSummary,
3240    ) -> bool {
3241        let mut did_extend = false;
3242        new_transforms.update_last(
3243            |last_transform| {
3244                if let DiffTransform::BufferContent {
3245                    summary,
3246                    inserted_hunk_info: inserted_hunk_anchor,
3247                } = last_transform
3248                {
3249                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3250                        *summary += summary_to_add;
3251                        did_extend = true;
3252                    }
3253                }
3254            },
3255            &(),
3256        );
3257        did_extend
3258    }
3259}
3260
3261#[cfg(any(test, feature = "test-support"))]
3262impl MultiBuffer {
3263    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3264        let buffer = cx.new(|cx| Buffer::local(text, cx));
3265        cx.new(|cx| Self::singleton(buffer, cx))
3266    }
3267
3268    pub fn build_multi<const COUNT: usize>(
3269        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3270        cx: &mut gpui::App,
3271    ) -> Entity<Self> {
3272        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3273        for (text, ranges) in excerpts {
3274            let buffer = cx.new(|cx| Buffer::local(text, cx));
3275            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3276                context: range,
3277                primary: None,
3278            });
3279            multi.update(cx, |multi, cx| {
3280                multi.push_excerpts(buffer, excerpt_ranges, cx)
3281            });
3282        }
3283
3284        multi
3285    }
3286
3287    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3288        cx.new(|cx| Self::singleton(buffer, cx))
3289    }
3290
3291    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3292        cx.new(|cx| {
3293            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3294            let mutation_count = rng.gen_range(1..=5);
3295            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3296            multibuffer
3297        })
3298    }
3299
3300    pub fn randomly_edit(
3301        &mut self,
3302        rng: &mut impl rand::Rng,
3303        edit_count: usize,
3304        cx: &mut Context<Self>,
3305    ) {
3306        use util::RandomCharIter;
3307
3308        let snapshot = self.read(cx);
3309        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3310        let mut last_end = None;
3311        for _ in 0..edit_count {
3312            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3313                break;
3314            }
3315
3316            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3317            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3318            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3319            last_end = Some(end);
3320
3321            let mut range = start..end;
3322            if rng.gen_bool(0.2) {
3323                mem::swap(&mut range.start, &mut range.end);
3324            }
3325
3326            let new_text_len = rng.gen_range(0..10);
3327            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3328
3329            edits.push((range, new_text.into()));
3330        }
3331        log::info!("mutating multi-buffer with {:?}", edits);
3332        drop(snapshot);
3333
3334        self.edit(edits, None, cx);
3335    }
3336
3337    pub fn randomly_edit_excerpts(
3338        &mut self,
3339        rng: &mut impl rand::Rng,
3340        mutation_count: usize,
3341        cx: &mut Context<Self>,
3342    ) {
3343        use rand::prelude::*;
3344        use std::env;
3345        use util::RandomCharIter;
3346
3347        let max_excerpts = env::var("MAX_EXCERPTS")
3348            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3349            .unwrap_or(5);
3350
3351        let mut buffers = Vec::new();
3352        for _ in 0..mutation_count {
3353            if rng.gen_bool(0.05) {
3354                log::info!("Clearing multi-buffer");
3355                self.clear(cx);
3356                continue;
3357            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3358                let ids = self.excerpt_ids();
3359                let mut excerpts = HashSet::default();
3360                for _ in 0..rng.gen_range(0..ids.len()) {
3361                    excerpts.extend(ids.choose(rng).copied());
3362                }
3363
3364                let line_count = rng.gen_range(0..5);
3365
3366                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3367
3368                self.expand_excerpts(
3369                    excerpts.iter().cloned(),
3370                    line_count,
3371                    ExpandExcerptDirection::UpAndDown,
3372                    cx,
3373                );
3374                continue;
3375            }
3376
3377            let excerpt_ids = self.excerpt_ids();
3378            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3379                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3380                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3381                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3382                    let buffer = buffers.last().unwrap().read(cx);
3383                    log::info!(
3384                        "Creating new buffer {} with text: {:?}",
3385                        buffer.remote_id(),
3386                        buffer.text()
3387                    );
3388                    buffers.last().unwrap().clone()
3389                } else {
3390                    self.buffers
3391                        .borrow()
3392                        .values()
3393                        .choose(rng)
3394                        .unwrap()
3395                        .buffer
3396                        .clone()
3397                };
3398
3399                let buffer = buffer_handle.read(cx);
3400                let buffer_text = buffer.text();
3401                let ranges = (0..rng.gen_range(0..5))
3402                    .map(|_| {
3403                        let end_ix =
3404                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3405                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3406                        ExcerptRange {
3407                            context: start_ix..end_ix,
3408                            primary: None,
3409                        }
3410                    })
3411                    .collect::<Vec<_>>();
3412                log::info!(
3413                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3414                    buffer_handle.read(cx).remote_id(),
3415                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3416                    ranges
3417                        .iter()
3418                        .map(|r| &buffer_text[r.context.clone()])
3419                        .collect::<Vec<_>>()
3420                );
3421
3422                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3423                log::info!("Inserted with ids: {:?}", excerpt_id);
3424            } else {
3425                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3426                let mut excerpts_to_remove = excerpt_ids
3427                    .choose_multiple(rng, remove_count)
3428                    .cloned()
3429                    .collect::<Vec<_>>();
3430                let snapshot = self.snapshot.borrow();
3431                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3432                drop(snapshot);
3433                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3434                self.remove_excerpts(excerpts_to_remove, cx);
3435            }
3436        }
3437    }
3438
3439    pub fn randomly_mutate(
3440        &mut self,
3441        rng: &mut impl rand::Rng,
3442        mutation_count: usize,
3443        cx: &mut Context<Self>,
3444    ) {
3445        use rand::prelude::*;
3446
3447        if rng.gen_bool(0.7) || self.singleton {
3448            let buffer = self
3449                .buffers
3450                .borrow()
3451                .values()
3452                .choose(rng)
3453                .map(|state| state.buffer.clone());
3454
3455            if let Some(buffer) = buffer {
3456                buffer.update(cx, |buffer, cx| {
3457                    if rng.gen() {
3458                        buffer.randomly_edit(rng, mutation_count, cx);
3459                    } else {
3460                        buffer.randomly_undo_redo(rng, cx);
3461                    }
3462                });
3463            } else {
3464                self.randomly_edit(rng, mutation_count, cx);
3465            }
3466        } else {
3467            self.randomly_edit_excerpts(rng, mutation_count, cx);
3468        }
3469
3470        self.check_invariants(cx);
3471    }
3472
3473    fn check_invariants(&self, cx: &App) {
3474        self.read(cx).check_invariants();
3475    }
3476}
3477
3478impl EventEmitter<Event> for MultiBuffer {}
3479
3480impl MultiBufferSnapshot {
3481    pub fn text(&self) -> String {
3482        self.chunks(0..self.len(), false)
3483            .map(|chunk| chunk.text)
3484            .collect()
3485    }
3486
3487    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3488        self.reversed_chunks_in_range(0..position.to_offset(self))
3489            .flat_map(|c| c.chars().rev())
3490    }
3491
3492    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3493        let mut cursor = self.cursor::<usize>();
3494        cursor.seek(&range.end);
3495        let current_chunks = cursor.region().as_ref().map(|region| {
3496            let start_overshoot = range.start.saturating_sub(region.range.start);
3497            let end_overshoot = range.end - region.range.start;
3498            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3499            let start = region.buffer_range.start + start_overshoot;
3500            region.buffer.reversed_chunks_in_range(start..end)
3501        });
3502        ReversedMultiBufferChunks {
3503            cursor,
3504            current_chunks,
3505            start: range.start,
3506            offset: range.end,
3507        }
3508    }
3509
3510    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3511        let offset = position.to_offset(self);
3512        self.text_for_range(offset..self.len())
3513            .flat_map(|chunk| chunk.chars())
3514    }
3515
3516    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3517        self.chunks(range, false).map(|chunk| chunk.text)
3518    }
3519
3520    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3521        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3522            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3523    }
3524
3525    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3526    where
3527        T: ToOffset,
3528    {
3529        let position = position.to_offset(self);
3530        position == self.clip_offset(position, Bias::Left)
3531            && self
3532                .bytes_in_range(position..self.len())
3533                .flatten()
3534                .copied()
3535                .take(needle.len())
3536                .eq(needle.bytes())
3537    }
3538
3539    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3540        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3541    }
3542
3543    pub fn diff_hunks_in_range<T: ToPoint>(
3544        &self,
3545        range: Range<T>,
3546    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3547        let query_range = range.start.to_point(self)..range.end.to_point(self);
3548        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3549            let diff = self.diffs.get(&buffer.remote_id())?;
3550            let buffer_start = buffer.anchor_before(buffer_range.start);
3551            let buffer_end = buffer.anchor_after(buffer_range.end);
3552            Some(
3553                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3554                    .filter_map(|hunk| {
3555                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3556                            return None;
3557                        }
3558                        Some((hunk.range.clone(), hunk))
3559                    }),
3560            )
3561        })
3562        .filter_map(move |(range, hunk, excerpt)| {
3563            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3564            {
3565                return None;
3566            }
3567            let end_row = if range.end.column == 0 {
3568                range.end.row
3569            } else {
3570                range.end.row + 1
3571            };
3572            Some(MultiBufferDiffHunk {
3573                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3574                buffer_id: excerpt.buffer_id,
3575                excerpt_id: excerpt.id,
3576                buffer_range: hunk.buffer_range.clone(),
3577                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3578                secondary_status: hunk.secondary_status,
3579            })
3580        })
3581    }
3582
3583    pub fn excerpt_ids_for_range<T: ToOffset>(
3584        &self,
3585        range: Range<T>,
3586    ) -> impl Iterator<Item = ExcerptId> + '_ {
3587        let range = range.start.to_offset(self)..range.end.to_offset(self);
3588        let mut cursor = self.cursor::<usize>();
3589        cursor.seek(&range.start);
3590        std::iter::from_fn(move || {
3591            let region = cursor.region()?;
3592            if region.range.start >= range.end {
3593                return None;
3594            }
3595            cursor.next_excerpt();
3596            Some(region.excerpt.id)
3597        })
3598    }
3599
3600    pub fn buffer_ids_for_range<T: ToOffset>(
3601        &self,
3602        range: Range<T>,
3603    ) -> impl Iterator<Item = BufferId> + '_ {
3604        let range = range.start.to_offset(self)..range.end.to_offset(self);
3605        let mut cursor = self.cursor::<usize>();
3606        cursor.seek(&range.start);
3607        std::iter::from_fn(move || {
3608            let region = cursor.region()?;
3609            if region.range.start > range.end
3610                || region.range.start == range.end && region.range.start > range.start
3611            {
3612                return None;
3613            }
3614            cursor.next_excerpt();
3615            Some(region.excerpt.buffer_id)
3616        })
3617    }
3618
3619    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3620        &self,
3621        ranges: impl Iterator<Item = Range<T>>,
3622    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3623        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3624    }
3625
3626    pub fn range_to_buffer_ranges<T: ToOffset>(
3627        &self,
3628        range: Range<T>,
3629    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3630        let start = range.start.to_offset(&self);
3631        let end = range.end.to_offset(&self);
3632
3633        let mut cursor = self.cursor::<usize>();
3634        cursor.seek(&start);
3635
3636        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3637        while let Some(region) = cursor.region() {
3638            if region.range.start > end {
3639                break;
3640            }
3641            if region.is_main_buffer {
3642                let start_overshoot = start.saturating_sub(region.range.start);
3643                let end_overshoot = end.saturating_sub(region.range.start);
3644                let start = region
3645                    .buffer_range
3646                    .end
3647                    .min(region.buffer_range.start + start_overshoot);
3648                let end = region
3649                    .buffer_range
3650                    .end
3651                    .min(region.buffer_range.start + end_overshoot);
3652                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3653                    *excerpt_id == region.excerpt.id && prev_range.end == start
3654                }) {
3655                    prev.1.end = end;
3656                } else {
3657                    result.push((region.buffer, start..end, region.excerpt.id));
3658                }
3659            }
3660            cursor.next();
3661        }
3662        result
3663    }
3664
3665    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3666        &self,
3667        range: Range<T>,
3668    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3669        let start = range.start.to_offset(&self);
3670        let end = range.end.to_offset(&self);
3671
3672        let mut cursor = self.cursor::<usize>();
3673        cursor.seek(&start);
3674
3675        std::iter::from_fn(move || {
3676            let region = cursor.region()?;
3677            if region.range.start > end {
3678                return None;
3679            }
3680            let start_overshoot = start.saturating_sub(region.range.start);
3681            let end_overshoot = end.saturating_sub(region.range.start);
3682            let start = region
3683                .buffer_range
3684                .end
3685                .min(region.buffer_range.start + start_overshoot);
3686            let end = region
3687                .buffer_range
3688                .end
3689                .min(region.buffer_range.start + end_overshoot);
3690
3691            let region_excerpt_id = region.excerpt.id;
3692            let deleted_hunk_anchor = if region.is_main_buffer {
3693                None
3694            } else {
3695                Some(self.anchor_before(region.range.start))
3696            };
3697            let result = (
3698                region.buffer,
3699                start..end,
3700                region_excerpt_id,
3701                deleted_hunk_anchor,
3702            );
3703            cursor.next();
3704            Some(result)
3705        })
3706    }
3707
3708    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3709    /// coordinates.
3710    ///
3711    /// The given callback will be called for every excerpt intersecting the given range. It will
3712    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3713    /// The callback should return an iterator of metadata items from that buffer, each paired
3714    /// with a buffer range.
3715    ///
3716    /// The returned iterator yields each of these metadata items, paired with its range in
3717    /// multi-buffer coordinates.
3718    fn lift_buffer_metadata<'a, D, M, I>(
3719        &'a self,
3720        query_range: Range<D>,
3721        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3722    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3723    where
3724        I: Iterator<Item = (Range<D>, M)> + 'a,
3725        D: TextDimension + Ord + Sub<D, Output = D>,
3726    {
3727        let max_position = D::from_text_summary(&self.text_summary());
3728        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3729        let mut cursor = self.cursor::<D>();
3730
3731        // Find the excerpt and buffer offset where the given range ends.
3732        cursor.seek(&query_range.end);
3733        let mut range_end = None;
3734        while let Some(region) = cursor.region() {
3735            if region.is_main_buffer {
3736                let mut buffer_end = region.buffer_range.start;
3737                let overshoot = if query_range.end > region.range.start {
3738                    query_range.end - region.range.start
3739                } else {
3740                    D::default()
3741                };
3742                buffer_end.add_assign(&overshoot);
3743                range_end = Some((region.excerpt.id, buffer_end));
3744                break;
3745            }
3746            cursor.next();
3747        }
3748
3749        cursor.seek(&query_range.start);
3750
3751        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3752            if region.range.start > D::zero(&()) {
3753                cursor.prev()
3754            }
3755        }
3756
3757        iter::from_fn(move || loop {
3758            let excerpt = cursor.excerpt()?;
3759
3760            // If we have already retrieved metadata for this excerpt, continue to use it.
3761            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3762                .as_mut()
3763                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3764            {
3765                Some(metadata)
3766            }
3767            // Otherwise, compute the intersection of the input range with the excerpt's range,
3768            // and retrieve the metadata for the resulting range.
3769            else {
3770                let region = cursor.region()?;
3771                let mut buffer_start;
3772                if region.is_main_buffer {
3773                    buffer_start = region.buffer_range.start;
3774                    if query_range.start > region.range.start {
3775                        let overshoot = query_range.start - region.range.start;
3776                        buffer_start.add_assign(&overshoot);
3777                    }
3778                    buffer_start = buffer_start.min(region.buffer_range.end);
3779                } else {
3780                    buffer_start = cursor.main_buffer_position()?;
3781                };
3782                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3783                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3784                    if excerpt.id == end_excerpt_id {
3785                        buffer_end = buffer_end.min(end_buffer_offset);
3786                    }
3787                }
3788
3789                if let Some(iterator) =
3790                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3791                {
3792                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3793                } else {
3794                    None
3795                }
3796            };
3797
3798            // Visit each metadata item.
3799            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3800            {
3801                // Find the multibuffer regions that contain the start and end of
3802                // the metadata item's range.
3803                if metadata_buffer_range.start > D::default() {
3804                    while let Some(region) = cursor.region() {
3805                        if region.is_main_buffer
3806                            && (region.buffer_range.end >= metadata_buffer_range.start
3807                                || cursor.is_at_end_of_excerpt())
3808                        {
3809                            break;
3810                        }
3811                        cursor.next();
3812                    }
3813                }
3814                let start_region = cursor.region()?;
3815                while let Some(region) = cursor.region() {
3816                    if region.is_main_buffer
3817                        && (region.buffer_range.end > metadata_buffer_range.end
3818                            || cursor.is_at_end_of_excerpt())
3819                    {
3820                        break;
3821                    }
3822                    cursor.next();
3823                }
3824                let end_region = cursor.region();
3825
3826                // Convert the metadata item's range into multibuffer coordinates.
3827                let mut start_position = start_region.range.start;
3828                let region_buffer_start = start_region.buffer_range.start;
3829                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3830                {
3831                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3832                    start_position = start_position.min(start_region.range.end);
3833                }
3834
3835                let mut end_position = max_position;
3836                if let Some(end_region) = &end_region {
3837                    end_position = end_region.range.start;
3838                    debug_assert!(end_region.is_main_buffer);
3839                    let region_buffer_start = end_region.buffer_range.start;
3840                    if metadata_buffer_range.end > region_buffer_start {
3841                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3842                    }
3843                    end_position = end_position.min(end_region.range.end);
3844                }
3845
3846                if start_position <= query_range.end && end_position >= query_range.start {
3847                    return Some((start_position..end_position, metadata, excerpt));
3848                }
3849            }
3850            // When there are no more metadata items for this excerpt, move to the next excerpt.
3851            else {
3852                current_excerpt_metadata.take();
3853                if let Some((end_excerpt_id, _)) = range_end {
3854                    if excerpt.id == end_excerpt_id {
3855                        return None;
3856                    }
3857                }
3858                cursor.next_excerpt();
3859            }
3860        })
3861    }
3862
3863    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3864        let offset = position.to_offset(self);
3865
3866        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3867        cursor.seek(&DimensionPair {
3868            key: offset,
3869            value: None,
3870        });
3871        cursor.seek_to_start_of_current_excerpt();
3872        let excerpt = cursor.excerpt()?;
3873
3874        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3875        let current_position = self
3876            .anchor_before(offset)
3877            .text_anchor
3878            .to_offset(&excerpt.buffer);
3879        let excerpt_end = excerpt
3880            .buffer
3881            .anchor_before(excerpt_end.min(current_position));
3882
3883        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3884            for hunk in diff.hunks_intersecting_range_rev(
3885                excerpt.range.context.start..excerpt_end,
3886                &excerpt.buffer,
3887            ) {
3888                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3889                if hunk_end >= current_position {
3890                    continue;
3891                }
3892                let start =
3893                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3894                        .to_point(&self);
3895                return Some(MultiBufferRow(start.row));
3896            }
3897        }
3898
3899        loop {
3900            cursor.prev_excerpt();
3901            let excerpt = cursor.excerpt()?;
3902
3903            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3904                continue;
3905            };
3906            let mut hunks =
3907                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3908            let Some(hunk) = hunks.next() else {
3909                continue;
3910            };
3911            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3912                .to_point(&self);
3913            return Some(MultiBufferRow(start.row));
3914        }
3915    }
3916
3917    pub fn has_diff_hunks(&self) -> bool {
3918        self.diffs.values().any(|diff| !diff.is_empty())
3919    }
3920
3921    pub fn surrounding_word<T: ToOffset>(
3922        &self,
3923        start: T,
3924        for_completion: bool,
3925    ) -> (Range<usize>, Option<CharKind>) {
3926        let mut start = start.to_offset(self);
3927        let mut end = start;
3928        let mut next_chars = self.chars_at(start).peekable();
3929        let mut prev_chars = self.reversed_chars_at(start).peekable();
3930
3931        let classifier = self
3932            .char_classifier_at(start)
3933            .for_completion(for_completion);
3934
3935        let word_kind = cmp::max(
3936            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3937            next_chars.peek().copied().map(|c| classifier.kind(c)),
3938        );
3939
3940        for ch in prev_chars {
3941            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3942                start -= ch.len_utf8();
3943            } else {
3944                break;
3945            }
3946        }
3947
3948        for ch in next_chars {
3949            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3950                end += ch.len_utf8();
3951            } else {
3952                break;
3953            }
3954        }
3955
3956        (start..end, word_kind)
3957    }
3958
3959    pub fn is_singleton(&self) -> bool {
3960        self.singleton
3961    }
3962
3963    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3964        if self.singleton {
3965            self.excerpts
3966                .iter()
3967                .next()
3968                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3969        } else {
3970            None
3971        }
3972    }
3973
3974    pub fn len(&self) -> usize {
3975        self.diff_transforms.summary().output.len
3976    }
3977
3978    pub fn is_empty(&self) -> bool {
3979        self.excerpts.summary().text.len == 0
3980    }
3981
3982    pub fn widest_line_number(&self) -> u32 {
3983        self.excerpts.summary().widest_line_number + 1
3984    }
3985
3986    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3987        let range = range.start.to_offset(self)..range.end.to_offset(self);
3988        let mut excerpts = self.cursor::<usize>();
3989        excerpts.seek(&range.start);
3990
3991        let mut chunk;
3992        let mut has_trailing_newline;
3993        let excerpt_bytes;
3994        if let Some(region) = excerpts.region() {
3995            let mut bytes = region.buffer.bytes_in_range(
3996                region.buffer_range.start + range.start - region.range.start
3997                    ..(region.buffer_range.start + range.end - region.range.start)
3998                        .min(region.buffer_range.end),
3999            );
4000            chunk = bytes.next().unwrap_or(&[][..]);
4001            excerpt_bytes = Some(bytes);
4002            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4003            if chunk.is_empty() && has_trailing_newline {
4004                chunk = b"\n";
4005                has_trailing_newline = false;
4006            }
4007        } else {
4008            chunk = &[][..];
4009            excerpt_bytes = None;
4010            has_trailing_newline = false;
4011        };
4012
4013        MultiBufferBytes {
4014            range,
4015            cursor: excerpts,
4016            excerpt_bytes,
4017            has_trailing_newline,
4018            chunk,
4019        }
4020    }
4021
4022    pub fn reversed_bytes_in_range<T: ToOffset>(
4023        &self,
4024        range: Range<T>,
4025    ) -> ReversedMultiBufferBytes {
4026        let range = range.start.to_offset(self)..range.end.to_offset(self);
4027        let mut chunks = self.reversed_chunks_in_range(range.clone());
4028        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4029        ReversedMultiBufferBytes {
4030            range,
4031            chunks,
4032            chunk,
4033        }
4034    }
4035
4036    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4037        let mut cursor = self.cursor::<Point>();
4038        cursor.seek(&Point::new(start_row.0, 0));
4039        let mut result = MultiBufferRows {
4040            point: Point::new(0, 0),
4041            is_empty: self.excerpts.is_empty(),
4042            cursor,
4043        };
4044        result.seek(start_row);
4045        result
4046    }
4047
4048    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4049        let mut chunks = MultiBufferChunks {
4050            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4051            range: 0..0,
4052            excerpts: self.excerpts.cursor(&()),
4053            diff_transforms: self.diff_transforms.cursor(&()),
4054            diffs: &self.diffs,
4055            diff_base_chunks: None,
4056            excerpt_chunks: None,
4057            buffer_chunk: None,
4058            language_aware,
4059        };
4060        let range = range.start.to_offset(self)..range.end.to_offset(self);
4061        chunks.seek(range);
4062        chunks
4063    }
4064
4065    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4066        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4067    }
4068
4069    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4070        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4071    }
4072
4073    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4074        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4075    }
4076
4077    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4078        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4079            buffer.clip_point_utf16(Unclipped(point), bias)
4080        })
4081    }
4082
4083    pub fn offset_to_point(&self, offset: usize) -> Point {
4084        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4085    }
4086
4087    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4088        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4089    }
4090
4091    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4092        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4093    }
4094
4095    pub fn point_to_offset(&self, point: Point) -> usize {
4096        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4097    }
4098
4099    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4100        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4101    }
4102
4103    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4104        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4105    }
4106
4107    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4108        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4109    }
4110
4111    fn clip_dimension<D>(
4112        &self,
4113        position: D,
4114        bias: Bias,
4115        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4116    ) -> D
4117    where
4118        D: TextDimension + Ord + Sub<D, Output = D>,
4119    {
4120        let mut cursor = self.cursor();
4121        cursor.seek(&position);
4122        if let Some(region) = cursor.region() {
4123            if position >= region.range.end {
4124                return region.range.end;
4125            }
4126            let overshoot = position - region.range.start;
4127            let mut buffer_position = region.buffer_range.start;
4128            buffer_position.add_assign(&overshoot);
4129            let clipped_buffer_position =
4130                clip_buffer_position(&region.buffer, buffer_position, bias);
4131            let mut position = region.range.start;
4132            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4133            position
4134        } else {
4135            D::from_text_summary(&self.text_summary())
4136        }
4137    }
4138
4139    fn convert_dimension<D1, D2>(
4140        &self,
4141        key: D1,
4142        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4143    ) -> D2
4144    where
4145        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4146        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4147    {
4148        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4149        cursor.seek(&DimensionPair { key, value: None });
4150        if let Some(region) = cursor.region() {
4151            if key >= region.range.end.key {
4152                return region.range.end.value.unwrap();
4153            }
4154            let start_key = region.range.start.key;
4155            let start_value = region.range.start.value.unwrap();
4156            let buffer_start_key = region.buffer_range.start.key;
4157            let buffer_start_value = region.buffer_range.start.value.unwrap();
4158            let mut buffer_key = buffer_start_key;
4159            buffer_key.add_assign(&(key - start_key));
4160            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4161            let mut result = start_value;
4162            result.add_assign(&(buffer_value - buffer_start_value));
4163            result
4164        } else {
4165            D2::from_text_summary(&self.text_summary())
4166        }
4167    }
4168
4169    pub fn point_to_buffer_offset<T: ToOffset>(
4170        &self,
4171        point: T,
4172    ) -> Option<(&BufferSnapshot, usize)> {
4173        let offset = point.to_offset(self);
4174        let mut cursor = self.cursor::<usize>();
4175        cursor.seek(&offset);
4176        let region = cursor.region()?;
4177        let overshoot = offset - region.range.start;
4178        let buffer_offset = region.buffer_range.start + overshoot;
4179        Some((region.buffer, buffer_offset))
4180    }
4181
4182    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4183        let mut cursor = self.cursor::<Point>();
4184        cursor.seek(&point);
4185        let region = cursor.region()?;
4186        let overshoot = point - region.range.start;
4187        let buffer_offset = region.buffer_range.start + overshoot;
4188        Some((region.buffer, buffer_offset, region.is_main_buffer))
4189    }
4190
4191    pub fn suggested_indents(
4192        &self,
4193        rows: impl IntoIterator<Item = u32>,
4194        cx: &App,
4195    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4196        let mut result = BTreeMap::new();
4197
4198        let mut rows_for_excerpt = Vec::new();
4199        let mut cursor = self.cursor::<Point>();
4200        let mut rows = rows.into_iter().peekable();
4201        let mut prev_row = u32::MAX;
4202        let mut prev_language_indent_size = IndentSize::default();
4203
4204        while let Some(row) = rows.next() {
4205            cursor.seek(&Point::new(row, 0));
4206            let Some(region) = cursor.region() else {
4207                continue;
4208            };
4209
4210            // Retrieve the language and indent size once for each disjoint region being indented.
4211            let single_indent_size = if row.saturating_sub(1) == prev_row {
4212                prev_language_indent_size
4213            } else {
4214                region
4215                    .buffer
4216                    .language_indent_size_at(Point::new(row, 0), cx)
4217            };
4218            prev_language_indent_size = single_indent_size;
4219            prev_row = row;
4220
4221            let start_buffer_row = region.buffer_range.start.row;
4222            let start_multibuffer_row = region.range.start.row;
4223            let end_multibuffer_row = region.range.end.row;
4224
4225            rows_for_excerpt.push(row);
4226            while let Some(next_row) = rows.peek().copied() {
4227                if end_multibuffer_row > next_row {
4228                    rows_for_excerpt.push(next_row);
4229                    rows.next();
4230                } else {
4231                    break;
4232                }
4233            }
4234
4235            let buffer_rows = rows_for_excerpt
4236                .drain(..)
4237                .map(|row| start_buffer_row + row - start_multibuffer_row);
4238            let buffer_indents = region
4239                .buffer
4240                .suggested_indents(buffer_rows, single_indent_size);
4241            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4242                (
4243                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4244                    indent,
4245                )
4246            });
4247            result.extend(multibuffer_indents);
4248        }
4249
4250        result
4251    }
4252
4253    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4254        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4255            let mut size = buffer.indent_size_for_line(range.start.row);
4256            size.len = size
4257                .len
4258                .min(range.end.column)
4259                .saturating_sub(range.start.column);
4260            size
4261        } else {
4262            IndentSize::spaces(0)
4263        }
4264    }
4265
4266    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4267        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4268            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4269        } else {
4270            LineIndent::spaces(0)
4271        }
4272    }
4273
4274    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4275        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4276
4277        if self.language_settings(cx).extend_comment_on_newline {
4278            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4279                let delimiters = language_scope.line_comment_prefixes();
4280                for delimiter in delimiters {
4281                    if *self
4282                        .chars_at(Point::new(row.0, indent.len() as u32))
4283                        .take(delimiter.chars().count())
4284                        .collect::<String>()
4285                        .as_str()
4286                        == **delimiter
4287                    {
4288                        indent.push_str(&delimiter);
4289                        break;
4290                    }
4291                }
4292            }
4293        }
4294
4295        indent
4296    }
4297
4298    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4299    where
4300        T: ToOffset,
4301    {
4302        for char in self.reversed_chars_at(position) {
4303            if !char.is_whitespace() {
4304                return false;
4305            }
4306            if char == '\n' {
4307                return true;
4308            }
4309        }
4310        return true;
4311    }
4312
4313    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4314        while row.0 > 0 {
4315            row.0 -= 1;
4316            if !self.is_line_blank(row) {
4317                return Some(row);
4318            }
4319        }
4320        None
4321    }
4322
4323    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4324        if let Some((_, range)) = self.buffer_line_for_row(row) {
4325            range.end.column - range.start.column
4326        } else {
4327            0
4328        }
4329    }
4330
4331    pub fn buffer_line_for_row(
4332        &self,
4333        row: MultiBufferRow,
4334    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4335        let mut cursor = self.cursor::<Point>();
4336        let point = Point::new(row.0, 0);
4337        cursor.seek(&point);
4338        let region = cursor.region()?;
4339        let overshoot = point.min(region.range.end) - region.range.start;
4340        let buffer_point = region.buffer_range.start + overshoot;
4341        if buffer_point.row > region.buffer_range.end.row {
4342            return None;
4343        }
4344        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4345        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4346            .min(region.buffer_range.end);
4347        Some((region.buffer, line_start..line_end))
4348    }
4349
4350    pub fn max_point(&self) -> Point {
4351        self.text_summary().lines
4352    }
4353
4354    pub fn max_row(&self) -> MultiBufferRow {
4355        MultiBufferRow(self.text_summary().lines.row)
4356    }
4357
4358    pub fn text_summary(&self) -> TextSummary {
4359        self.diff_transforms.summary().output
4360    }
4361
4362    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4363    where
4364        D: TextDimension,
4365        O: ToOffset,
4366    {
4367        let range = range.start.to_offset(self)..range.end.to_offset(self);
4368        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4369        cursor.seek(&range.start, Bias::Right, &());
4370
4371        let Some(first_transform) = cursor.item() else {
4372            return D::from_text_summary(&TextSummary::default());
4373        };
4374
4375        let diff_transform_start = cursor.start().0;
4376        let diff_transform_end = cursor.end(&()).0;
4377        let diff_start = range.start;
4378        let start_overshoot = diff_start - diff_transform_start;
4379        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4380
4381        let mut result = match first_transform {
4382            DiffTransform::BufferContent { .. } => {
4383                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4384                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4385                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4386            }
4387            DiffTransform::DeletedHunk {
4388                buffer_id,
4389                base_text_byte_range,
4390                has_trailing_newline,
4391                ..
4392            } => {
4393                let buffer_start = base_text_byte_range.start + start_overshoot;
4394                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4395                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4396                    panic!("{:?} is in non-existent deleted hunk", range.start)
4397                };
4398
4399                let include_trailing_newline =
4400                    *has_trailing_newline && range.end >= diff_transform_end;
4401                if include_trailing_newline {
4402                    buffer_end -= 1;
4403                }
4404
4405                let mut summary =
4406                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4407
4408                if include_trailing_newline {
4409                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4410                }
4411
4412                summary
4413            }
4414        };
4415        if range.end < diff_transform_end {
4416            return result;
4417        }
4418
4419        cursor.next(&());
4420        result.add_assign(&D::from_text_summary(&cursor.summary(
4421            &range.end,
4422            Bias::Right,
4423            &(),
4424        )));
4425
4426        let Some(last_transform) = cursor.item() else {
4427            return result;
4428        };
4429
4430        let overshoot = range.end - cursor.start().0;
4431        let suffix = match last_transform {
4432            DiffTransform::BufferContent { .. } => {
4433                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4434                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4435            }
4436            DiffTransform::DeletedHunk {
4437                base_text_byte_range,
4438                buffer_id,
4439                has_trailing_newline,
4440                ..
4441            } => {
4442                let buffer_end = base_text_byte_range.start + overshoot;
4443                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4444                    panic!("{:?} is in non-existent deleted hunk", range.end)
4445                };
4446
4447                let mut suffix = base_text
4448                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4449                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4450                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4451                }
4452                suffix
4453            }
4454        };
4455
4456        result.add_assign(&suffix);
4457        result
4458    }
4459
4460    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4461    where
4462        D: TextDimension,
4463    {
4464        // let mut range = range.start..range.end;
4465        let mut summary = D::zero(&());
4466        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4467        cursor.seek(&range.start, Bias::Right, &());
4468        if let Some(excerpt) = cursor.item() {
4469            let mut end_before_newline = cursor.end(&());
4470            if excerpt.has_trailing_newline {
4471                end_before_newline -= ExcerptOffset::new(1);
4472            }
4473
4474            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4475            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4476            let end_in_excerpt =
4477                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4478            summary.add_assign(
4479                &excerpt
4480                    .buffer
4481                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4482            );
4483
4484            if range.end > end_before_newline {
4485                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4486            }
4487
4488            cursor.next(&());
4489        }
4490
4491        if range.end > *cursor.start() {
4492            summary.add_assign(
4493                &cursor
4494                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4495                    .0,
4496            );
4497            if let Some(excerpt) = cursor.item() {
4498                range.end = cmp::max(*cursor.start(), range.end);
4499
4500                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4501                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4502                summary.add_assign(
4503                    &excerpt
4504                        .buffer
4505                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4506                );
4507            }
4508        }
4509
4510        summary
4511    }
4512
4513    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4514    where
4515        D: TextDimension + Ord + Sub<D, Output = D>,
4516    {
4517        self.summaries_for_anchors([anchor])[0]
4518    }
4519
4520    fn resolve_summary_for_anchor<D>(
4521        &self,
4522        anchor: &Anchor,
4523        excerpt_position: D,
4524        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4525    ) -> D
4526    where
4527        D: TextDimension + Ord + Sub<D, Output = D>,
4528    {
4529        loop {
4530            let transform_end_position = diff_transforms.end(&()).0 .0;
4531            let at_transform_end =
4532                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4533            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4534                diff_transforms.next(&());
4535                continue;
4536            }
4537
4538            let mut position = diff_transforms.start().1 .0;
4539            match diff_transforms.item() {
4540                Some(DiffTransform::DeletedHunk {
4541                    buffer_id,
4542                    base_text_byte_range,
4543                    ..
4544                }) => {
4545                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4546                        if let Some(base_text) =
4547                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4548                        {
4549                            if base_text.can_resolve(&diff_base_anchor) {
4550                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4551                                if base_text_offset >= base_text_byte_range.start
4552                                    && base_text_offset <= base_text_byte_range.end
4553                                {
4554                                    let position_in_hunk = base_text
4555                                        .text_summary_for_range::<D, _>(
4556                                            base_text_byte_range.start..base_text_offset,
4557                                        );
4558                                    position.add_assign(&position_in_hunk);
4559                                } else if at_transform_end {
4560                                    diff_transforms.next(&());
4561                                    continue;
4562                                }
4563                            }
4564                        }
4565                    }
4566                }
4567                _ => {
4568                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4569                        diff_transforms.next(&());
4570                        continue;
4571                    }
4572                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4573                    position.add_assign(&overshoot);
4574                }
4575            }
4576
4577            return position;
4578        }
4579    }
4580
4581    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4582        let mut cursor = self
4583            .excerpts
4584            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4585        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4586
4587        cursor.seek(&Some(locator), Bias::Left, &());
4588        if cursor.item().is_none() {
4589            cursor.next(&());
4590        }
4591
4592        let mut position = cursor.start().1;
4593        if let Some(excerpt) = cursor.item() {
4594            if excerpt.id == anchor.excerpt_id {
4595                let excerpt_buffer_start = excerpt
4596                    .buffer
4597                    .offset_for_anchor(&excerpt.range.context.start);
4598                let excerpt_buffer_end =
4599                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4600                let buffer_position = cmp::min(
4601                    excerpt_buffer_end,
4602                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4603                );
4604                if buffer_position > excerpt_buffer_start {
4605                    position.value += buffer_position - excerpt_buffer_start;
4606                }
4607            }
4608        }
4609        position
4610    }
4611
4612    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4613    where
4614        D: TextDimension + Ord + Sub<D, Output = D>,
4615        I: 'a + IntoIterator<Item = &'a Anchor>,
4616    {
4617        let mut anchors = anchors.into_iter().peekable();
4618        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4619        let mut diff_transforms_cursor = self
4620            .diff_transforms
4621            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4622        diff_transforms_cursor.next(&());
4623
4624        let mut summaries = Vec::new();
4625        while let Some(anchor) = anchors.peek() {
4626            let excerpt_id = anchor.excerpt_id;
4627            let excerpt_anchors = iter::from_fn(|| {
4628                let anchor = anchors.peek()?;
4629                if anchor.excerpt_id == excerpt_id {
4630                    Some(anchors.next().unwrap())
4631                } else {
4632                    None
4633                }
4634            });
4635
4636            let locator = self.excerpt_locator_for_id(excerpt_id);
4637            cursor.seek_forward(locator, Bias::Left, &());
4638            if cursor.item().is_none() {
4639                cursor.next(&());
4640            }
4641
4642            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4643            if let Some(excerpt) = cursor.item() {
4644                if excerpt.id != excerpt_id {
4645                    let position = self.resolve_summary_for_anchor(
4646                        &Anchor::min(),
4647                        excerpt_start_position,
4648                        &mut diff_transforms_cursor,
4649                    );
4650                    summaries.extend(excerpt_anchors.map(|_| position));
4651                    continue;
4652                }
4653                let excerpt_buffer_start =
4654                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4655                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4656                for (buffer_summary, anchor) in excerpt
4657                    .buffer
4658                    .summaries_for_anchors_with_payload::<D, _, _>(
4659                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4660                    )
4661                {
4662                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4663                    let mut position = excerpt_start_position;
4664                    if summary > excerpt_buffer_start {
4665                        position.add_assign(&(summary - excerpt_buffer_start));
4666                    }
4667
4668                    if position > diff_transforms_cursor.start().0 .0 {
4669                        diff_transforms_cursor.seek_forward(
4670                            &ExcerptDimension(position),
4671                            Bias::Left,
4672                            &(),
4673                        );
4674                    }
4675
4676                    summaries.push(self.resolve_summary_for_anchor(
4677                        anchor,
4678                        position,
4679                        &mut diff_transforms_cursor,
4680                    ));
4681                }
4682            } else {
4683                diff_transforms_cursor.seek_forward(
4684                    &ExcerptDimension(excerpt_start_position),
4685                    Bias::Left,
4686                    &(),
4687                );
4688                let position = self.resolve_summary_for_anchor(
4689                    &Anchor::max(),
4690                    excerpt_start_position,
4691                    &mut diff_transforms_cursor,
4692                );
4693                summaries.extend(excerpt_anchors.map(|_| position));
4694            }
4695        }
4696
4697        summaries
4698    }
4699
4700    pub fn dimensions_from_points<'a, D>(
4701        &'a self,
4702        points: impl 'a + IntoIterator<Item = Point>,
4703    ) -> impl 'a + Iterator<Item = D>
4704    where
4705        D: TextDimension + Sub<D, Output = D>,
4706    {
4707        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4708        cursor.seek(&DimensionPair {
4709            key: Point::default(),
4710            value: None,
4711        });
4712        let mut points = points.into_iter();
4713        iter::from_fn(move || {
4714            let point = points.next()?;
4715
4716            cursor.seek_forward(&DimensionPair {
4717                key: point,
4718                value: None,
4719            });
4720
4721            if let Some(region) = cursor.region() {
4722                let overshoot = point - region.range.start.key;
4723                let buffer_point = region.buffer_range.start.key + overshoot;
4724                let mut position = region.range.start.value.unwrap();
4725                position.add_assign(
4726                    &region
4727                        .buffer
4728                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4729                );
4730                return Some(position);
4731            } else {
4732                return Some(D::from_text_summary(&self.text_summary()));
4733            }
4734        })
4735    }
4736
4737    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4738    where
4739        I: 'a + IntoIterator<Item = &'a Anchor>,
4740    {
4741        let mut anchors = anchors.into_iter().enumerate().peekable();
4742        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4743        cursor.next(&());
4744
4745        let mut result = Vec::new();
4746
4747        while let Some((_, anchor)) = anchors.peek() {
4748            let old_excerpt_id = anchor.excerpt_id;
4749
4750            // Find the location where this anchor's excerpt should be.
4751            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4752            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4753
4754            if cursor.item().is_none() {
4755                cursor.next(&());
4756            }
4757
4758            let next_excerpt = cursor.item();
4759            let prev_excerpt = cursor.prev_item();
4760
4761            // Process all of the anchors for this excerpt.
4762            while let Some((_, anchor)) = anchors.peek() {
4763                if anchor.excerpt_id != old_excerpt_id {
4764                    break;
4765                }
4766                let (anchor_ix, anchor) = anchors.next().unwrap();
4767                let mut anchor = *anchor;
4768
4769                // Leave min and max anchors unchanged if invalid or
4770                // if the old excerpt still exists at this location
4771                let mut kept_position = next_excerpt
4772                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4773                    || old_excerpt_id == ExcerptId::max()
4774                    || old_excerpt_id == ExcerptId::min();
4775
4776                // If the old excerpt no longer exists at this location, then attempt to
4777                // find an equivalent position for this anchor in an adjacent excerpt.
4778                if !kept_position {
4779                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4780                        if excerpt.contains(&anchor) {
4781                            anchor.excerpt_id = excerpt.id;
4782                            kept_position = true;
4783                            break;
4784                        }
4785                    }
4786                }
4787
4788                // If there's no adjacent excerpt that contains the anchor's position,
4789                // then report that the anchor has lost its position.
4790                if !kept_position {
4791                    anchor = if let Some(excerpt) = next_excerpt {
4792                        let mut text_anchor = excerpt
4793                            .range
4794                            .context
4795                            .start
4796                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4797                        if text_anchor
4798                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4799                            .is_gt()
4800                        {
4801                            text_anchor = excerpt.range.context.end;
4802                        }
4803                        Anchor {
4804                            buffer_id: Some(excerpt.buffer_id),
4805                            excerpt_id: excerpt.id,
4806                            text_anchor,
4807                            diff_base_anchor: None,
4808                        }
4809                    } else if let Some(excerpt) = prev_excerpt {
4810                        let mut text_anchor = excerpt
4811                            .range
4812                            .context
4813                            .end
4814                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4815                        if text_anchor
4816                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4817                            .is_lt()
4818                        {
4819                            text_anchor = excerpt.range.context.start;
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 anchor.text_anchor.bias == Bias::Left {
4828                        Anchor::min()
4829                    } else {
4830                        Anchor::max()
4831                    };
4832                }
4833
4834                result.push((anchor_ix, anchor, kept_position));
4835            }
4836        }
4837        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4838        result
4839    }
4840
4841    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4842        self.anchor_at(position, Bias::Left)
4843    }
4844
4845    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4846        self.anchor_at(position, Bias::Right)
4847    }
4848
4849    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4850        let offset = position.to_offset(self);
4851
4852        // Find the given position in the diff transforms. Determine the corresponding
4853        // offset in the excerpts, and whether the position is within a deleted hunk.
4854        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4855        diff_transforms.seek(&offset, Bias::Right, &());
4856
4857        if offset == diff_transforms.start().0 && bias == Bias::Left {
4858            if let Some(prev_item) = diff_transforms.prev_item() {
4859                match prev_item {
4860                    DiffTransform::DeletedHunk { .. } => {
4861                        diff_transforms.prev(&());
4862                    }
4863                    _ => {}
4864                }
4865            }
4866        }
4867        let offset_in_transform = offset - diff_transforms.start().0;
4868        let mut excerpt_offset = diff_transforms.start().1;
4869        let mut diff_base_anchor = None;
4870        if let Some(DiffTransform::DeletedHunk {
4871            buffer_id,
4872            base_text_byte_range,
4873            has_trailing_newline,
4874            ..
4875        }) = diff_transforms.item()
4876        {
4877            let diff = self.diffs.get(buffer_id).expect("missing diff");
4878            if offset_in_transform > base_text_byte_range.len() {
4879                debug_assert!(*has_trailing_newline);
4880                bias = Bias::Right;
4881            } else {
4882                diff_base_anchor = Some(
4883                    diff.base_text()
4884                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4885                );
4886                bias = Bias::Left;
4887            }
4888        } else {
4889            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4890        };
4891
4892        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4893            return Anchor {
4894                buffer_id: Some(buffer_id),
4895                excerpt_id: *excerpt_id,
4896                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4897                diff_base_anchor,
4898            };
4899        }
4900
4901        let mut excerpts = self
4902            .excerpts
4903            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4904        excerpts.seek(&excerpt_offset, Bias::Right, &());
4905        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4906            excerpts.prev(&());
4907        }
4908        if let Some(excerpt) = excerpts.item() {
4909            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4910            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4911                overshoot -= 1;
4912                bias = Bias::Right;
4913            }
4914
4915            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4916            let text_anchor =
4917                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4918            Anchor {
4919                buffer_id: Some(excerpt.buffer_id),
4920                excerpt_id: excerpt.id,
4921                text_anchor,
4922                diff_base_anchor,
4923            }
4924        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4925            Anchor::min()
4926        } else {
4927            Anchor::max()
4928        }
4929    }
4930
4931    /// Returns an anchor for the given excerpt and text anchor,
4932    /// returns None if the excerpt_id is no longer valid.
4933    pub fn anchor_in_excerpt(
4934        &self,
4935        excerpt_id: ExcerptId,
4936        text_anchor: text::Anchor,
4937    ) -> Option<Anchor> {
4938        let locator = self.excerpt_locator_for_id(excerpt_id);
4939        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4940        cursor.seek(locator, Bias::Left, &());
4941        if let Some(excerpt) = cursor.item() {
4942            if excerpt.id == excerpt_id {
4943                let text_anchor = excerpt.clip_anchor(text_anchor);
4944                drop(cursor);
4945                return Some(Anchor {
4946                    buffer_id: Some(excerpt.buffer_id),
4947                    excerpt_id,
4948                    text_anchor,
4949                    diff_base_anchor: None,
4950                });
4951            }
4952        }
4953        None
4954    }
4955
4956    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4957        Some(self.excerpt(excerpt_id)?.range.context.clone())
4958    }
4959
4960    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4961        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4962            true
4963        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4964            excerpt.buffer.can_resolve(&anchor.text_anchor)
4965        } else {
4966            false
4967        }
4968    }
4969
4970    pub fn excerpts(
4971        &self,
4972    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4973        self.excerpts
4974            .iter()
4975            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4976    }
4977
4978    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4979        let excerpts = self.excerpts.cursor(&());
4980        let diff_transforms = self.diff_transforms.cursor(&());
4981        MultiBufferCursor {
4982            excerpts,
4983            diff_transforms,
4984            diffs: &self.diffs,
4985            cached_region: None,
4986        }
4987    }
4988
4989    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4990        let start_locator = self.excerpt_locator_for_id(id);
4991        let mut excerpts = self
4992            .excerpts
4993            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4994        excerpts.seek(&Some(start_locator), Bias::Left, &());
4995        excerpts.prev(&());
4996
4997        let mut diff_transforms = self
4998            .diff_transforms
4999            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5000        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5001        if diff_transforms.end(&()).1 < excerpts.start().1 {
5002            diff_transforms.next(&());
5003        }
5004
5005        let excerpt = excerpts.item()?;
5006        Some(MultiBufferExcerpt {
5007            excerpt,
5008            offset: diff_transforms.start().0 .0,
5009            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5010            excerpt_offset: excerpts.start().1.clone(),
5011            diff_transforms,
5012        })
5013    }
5014
5015    pub fn excerpt_boundaries_in_range<R, T>(
5016        &self,
5017        range: R,
5018    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5019    where
5020        R: RangeBounds<T>,
5021        T: ToOffset,
5022    {
5023        let start_offset;
5024        let start = match range.start_bound() {
5025            Bound::Included(start) => {
5026                start_offset = start.to_offset(self);
5027                Bound::Included(start_offset)
5028            }
5029            Bound::Excluded(_) => {
5030                panic!("not supported")
5031            }
5032            Bound::Unbounded => {
5033                start_offset = 0;
5034                Bound::Unbounded
5035            }
5036        };
5037        let end = match range.end_bound() {
5038            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5039            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5040            Bound::Unbounded => Bound::Unbounded,
5041        };
5042        let bounds = (start, end);
5043
5044        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5045        cursor.seek(&DimensionPair {
5046            key: start_offset,
5047            value: None,
5048        });
5049
5050        if cursor
5051            .region()
5052            .is_some_and(|region| bounds.contains(&region.range.start.key))
5053        {
5054            cursor.prev_excerpt();
5055        } else {
5056            cursor.seek_to_start_of_current_excerpt();
5057        }
5058        let mut prev_region = cursor.region();
5059
5060        cursor.next_excerpt();
5061
5062        let mut visited_end = false;
5063        iter::from_fn(move || loop {
5064            if self.singleton {
5065                return None;
5066            }
5067
5068            let next_region = cursor.region();
5069            cursor.next_excerpt();
5070
5071            let next_region_start = if let Some(region) = &next_region {
5072                if !bounds.contains(&region.range.start.key) {
5073                    prev_region = next_region;
5074                    continue;
5075                }
5076                region.range.start.value.unwrap()
5077            } else {
5078                if !bounds.contains(&self.len()) {
5079                    return None;
5080                }
5081                self.max_point()
5082            };
5083            let next_region_end = if let Some(region) = cursor.region() {
5084                region.range.start.value.unwrap()
5085            } else {
5086                self.max_point()
5087            };
5088
5089            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5090                id: region.excerpt.id,
5091                buffer: region.excerpt.buffer.clone(),
5092                buffer_id: region.excerpt.buffer_id,
5093                range: region.excerpt.range.clone(),
5094                end_row: MultiBufferRow(next_region_start.row),
5095            });
5096
5097            let next = next_region.as_ref().map(|region| ExcerptInfo {
5098                id: region.excerpt.id,
5099                buffer: region.excerpt.buffer.clone(),
5100                buffer_id: region.excerpt.buffer_id,
5101                range: region.excerpt.range.clone(),
5102                end_row: if region.excerpt.has_trailing_newline {
5103                    MultiBufferRow(next_region_end.row - 1)
5104                } else {
5105                    MultiBufferRow(next_region_end.row)
5106                },
5107            });
5108
5109            if next.is_none() {
5110                if visited_end {
5111                    return None;
5112                } else {
5113                    visited_end = true;
5114                }
5115            }
5116
5117            let row = MultiBufferRow(next_region_start.row);
5118
5119            prev_region = next_region;
5120
5121            return Some(ExcerptBoundary { row, prev, next });
5122        })
5123    }
5124
5125    pub fn edit_count(&self) -> usize {
5126        self.edit_count
5127    }
5128
5129    pub fn non_text_state_update_count(&self) -> usize {
5130        self.non_text_state_update_count
5131    }
5132
5133    /// Returns the smallest enclosing bracket ranges containing the given range or
5134    /// None if no brackets contain range or the range is not contained in a single
5135    /// excerpt
5136    ///
5137    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5138    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5139        &self,
5140        range: Range<T>,
5141        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5142    ) -> Option<(Range<usize>, Range<usize>)> {
5143        let range = range.start.to_offset(self)..range.end.to_offset(self);
5144        let mut excerpt = self.excerpt_containing(range.clone())?;
5145        let buffer = excerpt.buffer();
5146        let excerpt_buffer_range = excerpt.buffer_range();
5147
5148        // Filter to ranges contained in the excerpt
5149        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5150            excerpt_buffer_range.contains(&open.start)
5151                && excerpt_buffer_range.contains(&close.end)
5152                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5153        };
5154
5155        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5156            excerpt.map_range_to_buffer(range),
5157            Some(&range_filter),
5158        )?;
5159
5160        Some((
5161            excerpt.map_range_from_buffer(open),
5162            excerpt.map_range_from_buffer(close),
5163        ))
5164    }
5165
5166    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5167    /// not contained in a single excerpt
5168    pub fn enclosing_bracket_ranges<T: ToOffset>(
5169        &self,
5170        range: Range<T>,
5171    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5172        let range = range.start.to_offset(self)..range.end.to_offset(self);
5173        let mut excerpt = self.excerpt_containing(range.clone())?;
5174
5175        Some(
5176            excerpt
5177                .buffer()
5178                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5179                .filter_map(move |pair| {
5180                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5181                        Some((
5182                            excerpt.map_range_from_buffer(pair.open_range),
5183                            excerpt.map_range_from_buffer(pair.close_range),
5184                        ))
5185                    } else {
5186                        None
5187                    }
5188                }),
5189        )
5190    }
5191
5192    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5193    /// not contained in a single excerpt
5194    pub fn text_object_ranges<T: ToOffset>(
5195        &self,
5196        range: Range<T>,
5197        options: TreeSitterOptions,
5198    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5199        let range = range.start.to_offset(self)..range.end.to_offset(self);
5200        self.excerpt_containing(range.clone())
5201            .map(|mut excerpt| {
5202                excerpt
5203                    .buffer()
5204                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5205                    .filter_map(move |(range, text_object)| {
5206                        if excerpt.contains_buffer_range(range.clone()) {
5207                            Some((excerpt.map_range_from_buffer(range), text_object))
5208                        } else {
5209                            None
5210                        }
5211                    })
5212            })
5213            .into_iter()
5214            .flatten()
5215    }
5216
5217    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5218    /// not contained in a single excerpt
5219    pub fn bracket_ranges<T: ToOffset>(
5220        &self,
5221        range: Range<T>,
5222    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5223        let range = range.start.to_offset(self)..range.end.to_offset(self);
5224        let mut excerpt = self.excerpt_containing(range.clone())?;
5225
5226        Some(
5227            excerpt
5228                .buffer()
5229                .bracket_ranges(excerpt.map_range_to_buffer(range))
5230                .filter_map(move |pair| {
5231                    let buffer_range = pair.open_range.start..pair.close_range.end;
5232                    if excerpt.contains_buffer_range(buffer_range) {
5233                        Some((
5234                            excerpt.map_range_from_buffer(pair.open_range),
5235                            excerpt.map_range_from_buffer(pair.close_range),
5236                        ))
5237                    } else {
5238                        None
5239                    }
5240                }),
5241        )
5242    }
5243
5244    pub fn redacted_ranges<'a, T: ToOffset>(
5245        &'a self,
5246        range: Range<T>,
5247        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5248    ) -> impl Iterator<Item = Range<usize>> + 'a {
5249        let range = range.start.to_offset(self)..range.end.to_offset(self);
5250        self.lift_buffer_metadata(range, move |buffer, range| {
5251            if redaction_enabled(buffer.file()) {
5252                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5253            } else {
5254                None
5255            }
5256        })
5257        .map(|(range, _, _)| range)
5258    }
5259
5260    pub fn runnable_ranges(
5261        &self,
5262        range: Range<Anchor>,
5263    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5264        let range = range.start.to_offset(self)..range.end.to_offset(self);
5265        self.lift_buffer_metadata(range, move |buffer, range| {
5266            Some(
5267                buffer
5268                    .runnable_ranges(range.clone())
5269                    .filter(move |runnable| {
5270                        runnable.run_range.start >= range.start
5271                            && runnable.run_range.end < range.end
5272                    })
5273                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5274            )
5275        })
5276        .map(|(run_range, runnable, _)| language::RunnableRange {
5277            run_range,
5278            ..runnable
5279        })
5280    }
5281
5282    pub fn line_indents(
5283        &self,
5284        start_row: MultiBufferRow,
5285        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5286    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5287        let max_point = self.max_point();
5288        let mut cursor = self.cursor::<Point>();
5289        cursor.seek(&Point::new(start_row.0, 0));
5290        iter::from_fn(move || {
5291            let mut region = cursor.region()?;
5292            while !buffer_filter(&region.excerpt.buffer) {
5293                cursor.next();
5294                region = cursor.region()?;
5295            }
5296            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5297            let buffer_start_row =
5298                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5299
5300            let buffer_end_row = if region.is_main_buffer
5301                && (region.has_trailing_newline || region.range.end == max_point)
5302            {
5303                region.buffer_range.end.row
5304            } else {
5305                region.buffer_range.end.row.saturating_sub(1)
5306            };
5307
5308            let line_indents = region
5309                .buffer
5310                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5311            cursor.next();
5312            return Some(line_indents.map(move |(buffer_row, indent)| {
5313                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5314                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5315            }));
5316        })
5317        .flatten()
5318    }
5319
5320    pub fn reversed_line_indents(
5321        &self,
5322        end_row: MultiBufferRow,
5323        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5324    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5325        let max_point = self.max_point();
5326        let mut cursor = self.cursor::<Point>();
5327        cursor.seek(&Point::new(end_row.0, 0));
5328        iter::from_fn(move || {
5329            let mut region = cursor.region()?;
5330            while !buffer_filter(&region.excerpt.buffer) {
5331                cursor.prev();
5332                region = cursor.region()?;
5333            }
5334
5335            let buffer_start_row = region.buffer_range.start.row;
5336            let buffer_end_row = if region.is_main_buffer
5337                && (region.has_trailing_newline || region.range.end == max_point)
5338            {
5339                region.buffer_range.end.row + 1
5340            } else {
5341                region.buffer_range.end.row
5342            };
5343
5344            let overshoot = end_row.0 - region.range.start.row;
5345            let buffer_end_row =
5346                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5347
5348            let line_indents = region
5349                .buffer
5350                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5351            cursor.prev();
5352            return Some(line_indents.map(move |(buffer_row, indent)| {
5353                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5354                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5355            }));
5356        })
5357        .flatten()
5358    }
5359
5360    pub async fn enclosing_indent(
5361        &self,
5362        mut target_row: MultiBufferRow,
5363    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5364        let max_row = MultiBufferRow(self.max_point().row);
5365        if target_row >= max_row {
5366            return None;
5367        }
5368
5369        let mut target_indent = self.line_indent_for_row(target_row);
5370
5371        // If the current row is at the start of an indented block, we want to return this
5372        // block as the enclosing indent.
5373        if !target_indent.is_line_empty() && target_row < max_row {
5374            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5375            if !next_line_indent.is_line_empty()
5376                && target_indent.raw_len() < next_line_indent.raw_len()
5377            {
5378                target_indent = next_line_indent;
5379                target_row.0 += 1;
5380            }
5381        }
5382
5383        const SEARCH_ROW_LIMIT: u32 = 25000;
5384        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5385        const YIELD_INTERVAL: u32 = 100;
5386
5387        let mut accessed_row_counter = 0;
5388
5389        // If there is a blank line at the current row, search for the next non indented lines
5390        if target_indent.is_line_empty() {
5391            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5392            let end =
5393                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5394
5395            let mut non_empty_line_above = None;
5396            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5397                if row < start {
5398                    break;
5399                }
5400                accessed_row_counter += 1;
5401                if accessed_row_counter == YIELD_INTERVAL {
5402                    accessed_row_counter = 0;
5403                    yield_now().await;
5404                }
5405                if !indent.is_line_empty() {
5406                    non_empty_line_above = Some((row, indent));
5407                    break;
5408                }
5409            }
5410
5411            let mut non_empty_line_below = None;
5412            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5413                if row > end {
5414                    break;
5415                }
5416                accessed_row_counter += 1;
5417                if accessed_row_counter == YIELD_INTERVAL {
5418                    accessed_row_counter = 0;
5419                    yield_now().await;
5420                }
5421                if !indent.is_line_empty() {
5422                    non_empty_line_below = Some((row, indent));
5423                    break;
5424                }
5425            }
5426
5427            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5428                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5429                    if above_indent.raw_len() >= below_indent.raw_len() {
5430                        (above_row, above_indent)
5431                    } else {
5432                        (below_row, below_indent)
5433                    }
5434                }
5435                (Some(above), None) => above,
5436                (None, Some(below)) => below,
5437                _ => return None,
5438            };
5439
5440            target_indent = indent;
5441            target_row = row;
5442        }
5443
5444        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5445        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5446
5447        let mut start_indent = None;
5448        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5449            if row < start {
5450                break;
5451            }
5452            accessed_row_counter += 1;
5453            if accessed_row_counter == YIELD_INTERVAL {
5454                accessed_row_counter = 0;
5455                yield_now().await;
5456            }
5457            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5458                start_indent = Some((row, indent));
5459                break;
5460            }
5461        }
5462        let (start_row, start_indent_size) = start_indent?;
5463
5464        let mut end_indent = (end, None);
5465        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5466            if row > end {
5467                break;
5468            }
5469            accessed_row_counter += 1;
5470            if accessed_row_counter == YIELD_INTERVAL {
5471                accessed_row_counter = 0;
5472                yield_now().await;
5473            }
5474            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5475                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5476                break;
5477            }
5478        }
5479        let (end_row, end_indent_size) = end_indent;
5480
5481        let indent = if let Some(end_indent_size) = end_indent_size {
5482            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5483                start_indent_size
5484            } else {
5485                end_indent_size
5486            }
5487        } else {
5488            start_indent_size
5489        };
5490
5491        Some((start_row..end_row, indent))
5492    }
5493
5494    pub fn indent_guides_in_range<T: ToPoint>(
5495        &self,
5496        range: Range<T>,
5497        ignore_disabled_for_language: bool,
5498        cx: &App,
5499    ) -> impl Iterator<Item = IndentGuide> {
5500        let range = range.start.to_point(self)..range.end.to_point(self);
5501        let start_row = MultiBufferRow(range.start.row);
5502        let end_row = MultiBufferRow(range.end.row);
5503
5504        let mut row_indents = self.line_indents(start_row, |buffer| {
5505            let settings =
5506                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5507            settings.indent_guides.enabled || ignore_disabled_for_language
5508        });
5509
5510        let mut result = Vec::new();
5511        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5512
5513        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5514            if first_row > end_row {
5515                break;
5516            }
5517            let current_depth = indent_stack.len() as u32;
5518
5519            let settings =
5520                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5521            let tab_size = settings.tab_size.get() as u32;
5522
5523            // When encountering empty, continue until found useful line indent
5524            // then add to the indent stack with the depth found
5525            let mut found_indent = false;
5526            let mut last_row = first_row;
5527            if line_indent.is_line_empty() {
5528                while !found_indent {
5529                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5530                        break;
5531                    };
5532                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5533                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5534                        break;
5535                    }
5536
5537                    if new_line_indent.is_line_empty() {
5538                        continue;
5539                    }
5540                    last_row = target_row.min(end_row);
5541                    line_indent = new_line_indent;
5542                    found_indent = true;
5543                    break;
5544                }
5545            } else {
5546                found_indent = true
5547            }
5548
5549            let depth = if found_indent {
5550                line_indent.len(tab_size) / tab_size
5551                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5552            } else {
5553                current_depth
5554            };
5555
5556            match depth.cmp(&current_depth) {
5557                cmp::Ordering::Less => {
5558                    for _ in 0..(current_depth - depth) {
5559                        let mut indent = indent_stack.pop().unwrap();
5560                        if last_row != first_row {
5561                            // In this case, we landed on an empty row, had to seek forward,
5562                            // and discovered that the indent we where on is ending.
5563                            // This means that the last display row must
5564                            // be on line that ends this indent range, so we
5565                            // should display the range up to the first non-empty line
5566                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5567                        }
5568
5569                        result.push(indent)
5570                    }
5571                }
5572                cmp::Ordering::Greater => {
5573                    for next_depth in current_depth..depth {
5574                        indent_stack.push(IndentGuide {
5575                            buffer_id: buffer.remote_id(),
5576                            start_row: first_row,
5577                            end_row: last_row,
5578                            depth: next_depth,
5579                            tab_size,
5580                            settings: settings.indent_guides,
5581                        });
5582                    }
5583                }
5584                _ => {}
5585            }
5586
5587            for indent in indent_stack.iter_mut() {
5588                indent.end_row = last_row;
5589            }
5590        }
5591
5592        result.extend(indent_stack);
5593        result.into_iter()
5594    }
5595
5596    pub fn trailing_excerpt_update_count(&self) -> usize {
5597        self.trailing_excerpt_update_count
5598    }
5599
5600    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5601        self.point_to_buffer_offset(point)
5602            .and_then(|(buffer, _)| buffer.file())
5603    }
5604
5605    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5606        self.point_to_buffer_offset(point)
5607            .and_then(|(buffer, offset)| buffer.language_at(offset))
5608    }
5609
5610    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5611        self.excerpts
5612            .first()
5613            .map(|excerpt| &excerpt.buffer)
5614            .map(|buffer| {
5615                language_settings(
5616                    buffer.language().map(|language| language.name()),
5617                    buffer.file(),
5618                    cx,
5619                )
5620            })
5621            .unwrap_or_else(move || self.language_settings_at(0, cx))
5622    }
5623
5624    pub fn language_settings_at<'a, T: ToOffset>(
5625        &'a self,
5626        point: T,
5627        cx: &'a App,
5628    ) -> Cow<'a, LanguageSettings> {
5629        let mut language = None;
5630        let mut file = None;
5631        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5632            language = buffer.language_at(offset);
5633            file = buffer.file();
5634        }
5635        language_settings(language.map(|l| l.name()), file, cx)
5636    }
5637
5638    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5639        self.point_to_buffer_offset(point)
5640            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5641    }
5642
5643    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5644        self.point_to_buffer_offset(point)
5645            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5646            .unwrap_or_default()
5647    }
5648
5649    pub fn language_indent_size_at<T: ToOffset>(
5650        &self,
5651        position: T,
5652        cx: &App,
5653    ) -> Option<IndentSize> {
5654        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5655        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5656    }
5657
5658    pub fn is_dirty(&self) -> bool {
5659        self.is_dirty
5660    }
5661
5662    pub fn has_deleted_file(&self) -> bool {
5663        self.has_deleted_file
5664    }
5665
5666    pub fn has_conflict(&self) -> bool {
5667        self.has_conflict
5668    }
5669
5670    pub fn has_diagnostics(&self) -> bool {
5671        self.excerpts
5672            .iter()
5673            .any(|excerpt| excerpt.buffer.has_diagnostics())
5674    }
5675
5676    pub fn diagnostic_group(
5677        &self,
5678        buffer_id: BufferId,
5679        group_id: usize,
5680    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5681        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5682            if buffer.remote_id() != buffer_id {
5683                return None;
5684            };
5685            Some(
5686                buffer
5687                    .diagnostic_group(group_id)
5688                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5689            )
5690        })
5691        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5692    }
5693
5694    pub fn diagnostics_in_range<'a, T>(
5695        &'a self,
5696        range: Range<T>,
5697    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5698    where
5699        T: 'a
5700            + text::ToOffset
5701            + text::FromAnchor
5702            + TextDimension
5703            + Ord
5704            + Sub<T, Output = T>
5705            + fmt::Debug,
5706    {
5707        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5708            Some(
5709                buffer
5710                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5711                    .map(|entry| (entry.range, entry.diagnostic)),
5712            )
5713        })
5714        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5715    }
5716
5717    pub fn syntax_ancestor<T: ToOffset>(
5718        &self,
5719        range: Range<T>,
5720    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5721        let range = range.start.to_offset(self)..range.end.to_offset(self);
5722        let mut excerpt = self.excerpt_containing(range.clone())?;
5723        let node = excerpt
5724            .buffer()
5725            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5726        let node_range = node.byte_range();
5727        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5728            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5729        } else {
5730            MultiOrSingleBufferOffsetRange::Single(node_range)
5731        };
5732        Some((node, range))
5733    }
5734
5735    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5736        let (excerpt_id, _, buffer) = self.as_singleton()?;
5737        let outline = buffer.outline(theme)?;
5738        Some(Outline::new(
5739            outline
5740                .items
5741                .into_iter()
5742                .flat_map(|item| {
5743                    Some(OutlineItem {
5744                        depth: item.depth,
5745                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5746                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5747                        text: item.text,
5748                        highlight_ranges: item.highlight_ranges,
5749                        name_ranges: item.name_ranges,
5750                        body_range: item.body_range.and_then(|body_range| {
5751                            Some(
5752                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5753                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5754                            )
5755                        }),
5756                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5757                            Some(
5758                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5759                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5760                            )
5761                        }),
5762                    })
5763                })
5764                .collect(),
5765        ))
5766    }
5767
5768    pub fn symbols_containing<T: ToOffset>(
5769        &self,
5770        offset: T,
5771        theme: Option<&SyntaxTheme>,
5772    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5773        let anchor = self.anchor_before(offset);
5774        let excerpt_id = anchor.excerpt_id;
5775        let excerpt = self.excerpt(excerpt_id)?;
5776        Some((
5777            excerpt.buffer_id,
5778            excerpt
5779                .buffer
5780                .symbols_containing(anchor.text_anchor, theme)
5781                .into_iter()
5782                .flatten()
5783                .flat_map(|item| {
5784                    Some(OutlineItem {
5785                        depth: item.depth,
5786                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5787                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5788                        text: item.text,
5789                        highlight_ranges: item.highlight_ranges,
5790                        name_ranges: item.name_ranges,
5791                        body_range: item.body_range.and_then(|body_range| {
5792                            Some(
5793                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5794                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5795                            )
5796                        }),
5797                        annotation_range: item.annotation_range.and_then(|body_range| {
5798                            Some(
5799                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5800                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5801                            )
5802                        }),
5803                    })
5804                })
5805                .collect(),
5806        ))
5807    }
5808
5809    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5810        if id == ExcerptId::min() {
5811            Locator::min_ref()
5812        } else if id == ExcerptId::max() {
5813            Locator::max_ref()
5814        } else {
5815            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5816            cursor.seek(&id, Bias::Left, &());
5817            if let Some(entry) = cursor.item() {
5818                if entry.id == id {
5819                    return &entry.locator;
5820                }
5821            }
5822            panic!("invalid excerpt id {:?}", id)
5823        }
5824    }
5825
5826    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5827    fn excerpt_locators_for_ids(
5828        &self,
5829        ids: impl IntoIterator<Item = ExcerptId>,
5830    ) -> SmallVec<[Locator; 1]> {
5831        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5832        sorted_ids.sort_unstable();
5833        let mut locators = SmallVec::new();
5834
5835        while sorted_ids.last() == Some(&ExcerptId::max()) {
5836            sorted_ids.pop();
5837            if let Some(mapping) = self.excerpt_ids.last() {
5838                locators.push(mapping.locator.clone());
5839            }
5840        }
5841
5842        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5843        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5844            sorted_ids.next();
5845            if let Some(mapping) = self.excerpt_ids.first() {
5846                locators.push(mapping.locator.clone());
5847            }
5848        }
5849
5850        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5851        for id in sorted_ids {
5852            if cursor.seek_forward(&id, Bias::Left, &()) {
5853                locators.push(cursor.item().unwrap().locator.clone());
5854            } else {
5855                panic!("invalid excerpt id {:?}", id);
5856            }
5857        }
5858
5859        locators.sort_unstable();
5860        locators
5861    }
5862
5863    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5864        Some(self.excerpt(excerpt_id)?.buffer_id)
5865    }
5866
5867    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5868        Some(&self.excerpt(excerpt_id)?.buffer)
5869    }
5870
5871    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5872        let mut cursor = self
5873            .excerpts
5874            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5875        let locator = self.excerpt_locator_for_id(excerpt_id);
5876        if cursor.seek(&Some(locator), Bias::Left, &()) {
5877            let start = cursor.start().1.clone();
5878            let end = cursor.end(&()).1;
5879            let mut diff_transforms = self
5880                .diff_transforms
5881                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5882            diff_transforms.seek(&start, Bias::Left, &());
5883            let overshoot = start.0 - diff_transforms.start().0 .0;
5884            let start = diff_transforms.start().1 .0 + overshoot;
5885            diff_transforms.seek(&end, Bias::Right, &());
5886            let overshoot = end.0 - diff_transforms.start().0 .0;
5887            let end = diff_transforms.start().1 .0 + overshoot;
5888            Some(start..end)
5889        } else {
5890            None
5891        }
5892    }
5893
5894    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5895        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5896        let locator = self.excerpt_locator_for_id(excerpt_id);
5897        if cursor.seek(&Some(locator), Bias::Left, &()) {
5898            if let Some(excerpt) = cursor.item() {
5899                return Some(excerpt.range.context.clone());
5900            }
5901        }
5902        None
5903    }
5904
5905    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5906        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5907        let locator = self.excerpt_locator_for_id(excerpt_id);
5908        cursor.seek(&Some(locator), Bias::Left, &());
5909        if let Some(excerpt) = cursor.item() {
5910            if excerpt.id == excerpt_id {
5911                return Some(excerpt);
5912            }
5913        }
5914        None
5915    }
5916
5917    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5918    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5919        let range = range.start.to_offset(self)..range.end.to_offset(self);
5920        let mut cursor = self.cursor::<usize>();
5921        cursor.seek(&range.start);
5922
5923        let start_excerpt = cursor.excerpt()?;
5924        if range.end != range.start {
5925            cursor.seek_forward(&range.end);
5926            if cursor.excerpt()?.id != start_excerpt.id {
5927                return None;
5928            }
5929        }
5930
5931        cursor.seek_to_start_of_current_excerpt();
5932        let region = cursor.region()?;
5933        let offset = region.range.start;
5934        let buffer_offset = region.buffer_range.start;
5935        let excerpt_offset = cursor.excerpts.start().clone();
5936        Some(MultiBufferExcerpt {
5937            diff_transforms: cursor.diff_transforms,
5938            excerpt: start_excerpt,
5939            offset,
5940            buffer_offset,
5941            excerpt_offset,
5942        })
5943    }
5944
5945    pub fn selections_in_range<'a>(
5946        &'a self,
5947        range: &'a Range<Anchor>,
5948        include_local: bool,
5949    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5950        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5951        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5952        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5953        cursor.seek(start_locator, Bias::Left, &());
5954        cursor
5955            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5956            .flat_map(move |excerpt| {
5957                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5958                if excerpt.id == range.start.excerpt_id {
5959                    query_range.start = range.start.text_anchor;
5960                }
5961                if excerpt.id == range.end.excerpt_id {
5962                    query_range.end = range.end.text_anchor;
5963                }
5964
5965                excerpt
5966                    .buffer
5967                    .selections_in_range(query_range, include_local)
5968                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5969                        selections.map(move |selection| {
5970                            let mut start = Anchor {
5971                                buffer_id: Some(excerpt.buffer_id),
5972                                excerpt_id: excerpt.id,
5973                                text_anchor: selection.start,
5974                                diff_base_anchor: None,
5975                            };
5976                            let mut end = Anchor {
5977                                buffer_id: Some(excerpt.buffer_id),
5978                                excerpt_id: excerpt.id,
5979                                text_anchor: selection.end,
5980                                diff_base_anchor: None,
5981                            };
5982                            if range.start.cmp(&start, self).is_gt() {
5983                                start = range.start;
5984                            }
5985                            if range.end.cmp(&end, self).is_lt() {
5986                                end = range.end;
5987                            }
5988
5989                            (
5990                                replica_id,
5991                                line_mode,
5992                                cursor_shape,
5993                                Selection {
5994                                    id: selection.id,
5995                                    start,
5996                                    end,
5997                                    reversed: selection.reversed,
5998                                    goal: selection.goal,
5999                                },
6000                            )
6001                        })
6002                    })
6003            })
6004    }
6005
6006    pub fn show_headers(&self) -> bool {
6007        self.show_headers
6008    }
6009
6010    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6011        self.diffs.get(&buffer_id)
6012    }
6013}
6014
6015#[cfg(any(test, feature = "test-support"))]
6016impl MultiBufferSnapshot {
6017    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6018        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6019        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6020        start..end
6021    }
6022
6023    #[cfg(any(test, feature = "test-support"))]
6024    fn check_invariants(&self) {
6025        let excerpts = self.excerpts.items(&());
6026        let excerpt_ids = self.excerpt_ids.items(&());
6027
6028        for (ix, excerpt) in excerpts.iter().enumerate() {
6029            if ix == 0 {
6030                if excerpt.locator <= Locator::min() {
6031                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6032                }
6033            } else if excerpt.locator <= excerpts[ix - 1].locator {
6034                panic!("excerpts are out-of-order: {:?}", excerpts);
6035            }
6036        }
6037
6038        for (ix, entry) in excerpt_ids.iter().enumerate() {
6039            if ix == 0 {
6040                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6041                    panic!("invalid first excerpt id {:?}", entry.id);
6042                }
6043            } else if entry.id <= excerpt_ids[ix - 1].id {
6044                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6045            }
6046        }
6047
6048        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6049            panic!(
6050                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6051                self.excerpts.summary().text.len,
6052                self.diff_transforms.summary().input,
6053                self.diff_transforms.items(&()),
6054            );
6055        }
6056
6057        let mut prev_transform: Option<&DiffTransform> = None;
6058        for item in self.diff_transforms.iter() {
6059            if let DiffTransform::BufferContent {
6060                summary,
6061                inserted_hunk_info,
6062            } = item
6063            {
6064                if let Some(DiffTransform::BufferContent {
6065                    inserted_hunk_info: prev_inserted_hunk_info,
6066                    ..
6067                }) = prev_transform
6068                {
6069                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6070                        panic!(
6071                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6072                            self.diff_transforms.items(&()));
6073                    }
6074                }
6075                if summary.len == 0 && !self.is_empty() {
6076                    panic!("empty buffer content transform");
6077                }
6078            }
6079            prev_transform = Some(item);
6080        }
6081    }
6082}
6083
6084impl<'a, D> MultiBufferCursor<'a, D>
6085where
6086    D: TextDimension + Ord + Sub<D, Output = D>,
6087{
6088    fn seek(&mut self, position: &D) {
6089        self.cached_region.take();
6090        self.diff_transforms
6091            .seek(&OutputDimension(*position), Bias::Right, &());
6092        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6093            self.diff_transforms.prev(&());
6094        }
6095
6096        let mut excerpt_position = self.diff_transforms.start().1 .0;
6097        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6098            let overshoot = *position - self.diff_transforms.start().0 .0;
6099            excerpt_position.add_assign(&overshoot);
6100        }
6101
6102        self.excerpts
6103            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6104        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6105            self.excerpts.prev(&());
6106        }
6107    }
6108
6109    fn seek_forward(&mut self, position: &D) {
6110        self.cached_region.take();
6111        self.diff_transforms
6112            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6113        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6114            self.diff_transforms.prev(&());
6115        }
6116
6117        let overshoot = *position - self.diff_transforms.start().0 .0;
6118        let mut excerpt_position = self.diff_transforms.start().1 .0;
6119        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6120            excerpt_position.add_assign(&overshoot);
6121        }
6122
6123        self.excerpts
6124            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6125        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6126            self.excerpts.prev(&());
6127        }
6128    }
6129
6130    fn next_excerpt(&mut self) {
6131        self.excerpts.next(&());
6132        self.seek_to_start_of_current_excerpt();
6133    }
6134
6135    fn prev_excerpt(&mut self) {
6136        self.excerpts.prev(&());
6137        self.seek_to_start_of_current_excerpt();
6138    }
6139
6140    fn seek_to_start_of_current_excerpt(&mut self) {
6141        self.cached_region.take();
6142        self.diff_transforms
6143            .seek(self.excerpts.start(), Bias::Left, &());
6144        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6145            && self.diff_transforms.start().1 < *self.excerpts.start()
6146            && self.diff_transforms.next_item().is_some()
6147        {
6148            self.diff_transforms.next(&());
6149        }
6150    }
6151
6152    fn next(&mut self) {
6153        self.cached_region.take();
6154        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6155            cmp::Ordering::Less => self.diff_transforms.next(&()),
6156            cmp::Ordering::Greater => self.excerpts.next(&()),
6157            cmp::Ordering::Equal => {
6158                self.diff_transforms.next(&());
6159                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6160                    || self.diff_transforms.item().is_none()
6161                {
6162                    self.excerpts.next(&());
6163                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6164                    self.diff_transforms.item()
6165                {
6166                    if self
6167                        .excerpts
6168                        .item()
6169                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6170                    {
6171                        self.excerpts.next(&());
6172                    }
6173                }
6174            }
6175        }
6176    }
6177
6178    fn prev(&mut self) {
6179        self.cached_region.take();
6180        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6181            cmp::Ordering::Less => self.excerpts.prev(&()),
6182            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6183            cmp::Ordering::Equal => {
6184                self.diff_transforms.prev(&());
6185                if self.diff_transforms.start().1 < *self.excerpts.start()
6186                    || self.diff_transforms.item().is_none()
6187                {
6188                    self.excerpts.prev(&());
6189                }
6190            }
6191        }
6192    }
6193
6194    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6195        if self.cached_region.is_none() {
6196            self.cached_region = self.build_region();
6197        }
6198        self.cached_region.clone()
6199    }
6200
6201    fn is_at_end_of_excerpt(&mut self) -> bool {
6202        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6203            return false;
6204        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6205            || self.diff_transforms.item().is_none()
6206        {
6207            return true;
6208        }
6209
6210        let next_transform = self.diff_transforms.next_item();
6211        next_transform.map_or(true, |next_transform| match next_transform {
6212            DiffTransform::BufferContent { .. } => true,
6213            DiffTransform::DeletedHunk { hunk_info, .. } => self
6214                .excerpts
6215                .item()
6216                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6217        })
6218    }
6219
6220    fn main_buffer_position(&self) -> Option<D> {
6221        let excerpt = self.excerpts.item()?;
6222        let buffer = &excerpt.buffer;
6223        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6224        let mut buffer_start = buffer_context_start;
6225        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6226        buffer_start.add_assign(&overshoot);
6227        Some(buffer_start)
6228    }
6229
6230    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6231        let excerpt = self.excerpts.item()?;
6232        match self.diff_transforms.item()? {
6233            DiffTransform::DeletedHunk {
6234                buffer_id,
6235                base_text_byte_range,
6236                has_trailing_newline,
6237                hunk_info,
6238                ..
6239            } => {
6240                let diff = self.diffs.get(&buffer_id)?;
6241                let buffer = diff.base_text();
6242                let mut rope_cursor = buffer.as_rope().cursor(0);
6243                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6244                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6245                let mut buffer_end = buffer_start;
6246                buffer_end.add_assign(&buffer_range_len);
6247                let start = self.diff_transforms.start().0 .0;
6248                let end = self.diff_transforms.end(&()).0 .0;
6249                return Some(MultiBufferRegion {
6250                    buffer,
6251                    excerpt,
6252                    has_trailing_newline: *has_trailing_newline,
6253                    is_main_buffer: false,
6254                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6255                        hunk_info.hunk_secondary_status,
6256                    )),
6257                    buffer_range: buffer_start..buffer_end,
6258                    range: start..end,
6259                });
6260            }
6261            DiffTransform::BufferContent {
6262                inserted_hunk_info, ..
6263            } => {
6264                let buffer = &excerpt.buffer;
6265                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6266
6267                let mut start = self.diff_transforms.start().0 .0;
6268                let mut buffer_start = buffer_context_start;
6269                if self.diff_transforms.start().1 < *self.excerpts.start() {
6270                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6271                    start.add_assign(&overshoot);
6272                } else {
6273                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6274                    buffer_start.add_assign(&overshoot);
6275                }
6276
6277                let mut end;
6278                let mut buffer_end;
6279                let has_trailing_newline;
6280                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6281                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6282                    end = self.diff_transforms.end(&()).0 .0;
6283                    buffer_end = buffer_context_start;
6284                    buffer_end.add_assign(&overshoot);
6285                    has_trailing_newline = false;
6286                } else {
6287                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6288                    end = self.diff_transforms.start().0 .0;
6289                    end.add_assign(&overshoot);
6290                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6291                    has_trailing_newline = excerpt.has_trailing_newline;
6292                };
6293
6294                Some(MultiBufferRegion {
6295                    buffer,
6296                    excerpt,
6297                    has_trailing_newline,
6298                    is_main_buffer: true,
6299                    diff_hunk_status: inserted_hunk_info
6300                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6301                    buffer_range: buffer_start..buffer_end,
6302                    range: start..end,
6303                })
6304            }
6305        }
6306    }
6307
6308    fn excerpt(&self) -> Option<&'a Excerpt> {
6309        self.excerpts.item()
6310    }
6311}
6312
6313impl History {
6314    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6315        self.transaction_depth += 1;
6316        if self.transaction_depth == 1 {
6317            let id = self.next_transaction_id.tick();
6318            self.undo_stack.push(Transaction {
6319                id,
6320                buffer_transactions: Default::default(),
6321                first_edit_at: now,
6322                last_edit_at: now,
6323                suppress_grouping: false,
6324            });
6325            Some(id)
6326        } else {
6327            None
6328        }
6329    }
6330
6331    fn end_transaction(
6332        &mut self,
6333        now: Instant,
6334        buffer_transactions: HashMap<BufferId, TransactionId>,
6335    ) -> bool {
6336        assert_ne!(self.transaction_depth, 0);
6337        self.transaction_depth -= 1;
6338        if self.transaction_depth == 0 {
6339            if buffer_transactions.is_empty() {
6340                self.undo_stack.pop();
6341                false
6342            } else {
6343                self.redo_stack.clear();
6344                let transaction = self.undo_stack.last_mut().unwrap();
6345                transaction.last_edit_at = now;
6346                for (buffer_id, transaction_id) in buffer_transactions {
6347                    transaction
6348                        .buffer_transactions
6349                        .entry(buffer_id)
6350                        .or_insert(transaction_id);
6351                }
6352                true
6353            }
6354        } else {
6355            false
6356        }
6357    }
6358
6359    fn push_transaction<'a, T>(
6360        &mut self,
6361        buffer_transactions: T,
6362        now: Instant,
6363        cx: &Context<MultiBuffer>,
6364    ) where
6365        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6366    {
6367        assert_eq!(self.transaction_depth, 0);
6368        let transaction = Transaction {
6369            id: self.next_transaction_id.tick(),
6370            buffer_transactions: buffer_transactions
6371                .into_iter()
6372                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6373                .collect(),
6374            first_edit_at: now,
6375            last_edit_at: now,
6376            suppress_grouping: false,
6377        };
6378        if !transaction.buffer_transactions.is_empty() {
6379            self.undo_stack.push(transaction);
6380            self.redo_stack.clear();
6381        }
6382    }
6383
6384    fn finalize_last_transaction(&mut self) {
6385        if let Some(transaction) = self.undo_stack.last_mut() {
6386            transaction.suppress_grouping = true;
6387        }
6388    }
6389
6390    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6391        if let Some(ix) = self
6392            .undo_stack
6393            .iter()
6394            .rposition(|transaction| transaction.id == transaction_id)
6395        {
6396            Some(self.undo_stack.remove(ix))
6397        } else if let Some(ix) = self
6398            .redo_stack
6399            .iter()
6400            .rposition(|transaction| transaction.id == transaction_id)
6401        {
6402            Some(self.redo_stack.remove(ix))
6403        } else {
6404            None
6405        }
6406    }
6407
6408    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6409        self.undo_stack
6410            .iter()
6411            .find(|transaction| transaction.id == transaction_id)
6412            .or_else(|| {
6413                self.redo_stack
6414                    .iter()
6415                    .find(|transaction| transaction.id == transaction_id)
6416            })
6417    }
6418
6419    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6420        self.undo_stack
6421            .iter_mut()
6422            .find(|transaction| transaction.id == transaction_id)
6423            .or_else(|| {
6424                self.redo_stack
6425                    .iter_mut()
6426                    .find(|transaction| transaction.id == transaction_id)
6427            })
6428    }
6429
6430    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6431        assert_eq!(self.transaction_depth, 0);
6432        if let Some(transaction) = self.undo_stack.pop() {
6433            self.redo_stack.push(transaction);
6434            self.redo_stack.last_mut()
6435        } else {
6436            None
6437        }
6438    }
6439
6440    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6441        assert_eq!(self.transaction_depth, 0);
6442        if let Some(transaction) = self.redo_stack.pop() {
6443            self.undo_stack.push(transaction);
6444            self.undo_stack.last_mut()
6445        } else {
6446            None
6447        }
6448    }
6449
6450    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6451        let ix = self
6452            .undo_stack
6453            .iter()
6454            .rposition(|transaction| transaction.id == transaction_id)?;
6455        let transaction = self.undo_stack.remove(ix);
6456        self.redo_stack.push(transaction);
6457        self.redo_stack.last()
6458    }
6459
6460    fn group(&mut self) -> Option<TransactionId> {
6461        let mut count = 0;
6462        let mut transactions = self.undo_stack.iter();
6463        if let Some(mut transaction) = transactions.next_back() {
6464            while let Some(prev_transaction) = transactions.next_back() {
6465                if !prev_transaction.suppress_grouping
6466                    && transaction.first_edit_at - prev_transaction.last_edit_at
6467                        <= self.group_interval
6468                {
6469                    transaction = prev_transaction;
6470                    count += 1;
6471                } else {
6472                    break;
6473                }
6474            }
6475        }
6476        self.group_trailing(count)
6477    }
6478
6479    fn group_until(&mut self, transaction_id: TransactionId) {
6480        let mut count = 0;
6481        for transaction in self.undo_stack.iter().rev() {
6482            if transaction.id == transaction_id {
6483                self.group_trailing(count);
6484                break;
6485            } else if transaction.suppress_grouping {
6486                break;
6487            } else {
6488                count += 1;
6489            }
6490        }
6491    }
6492
6493    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6494        let new_len = self.undo_stack.len() - n;
6495        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6496        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6497            if let Some(transaction) = transactions_to_merge.last() {
6498                last_transaction.last_edit_at = transaction.last_edit_at;
6499            }
6500            for to_merge in transactions_to_merge {
6501                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6502                    last_transaction
6503                        .buffer_transactions
6504                        .entry(*buffer_id)
6505                        .or_insert(*transaction_id);
6506                }
6507            }
6508        }
6509
6510        self.undo_stack.truncate(new_len);
6511        self.undo_stack.last().map(|t| t.id)
6512    }
6513}
6514
6515impl Excerpt {
6516    fn new(
6517        id: ExcerptId,
6518        locator: Locator,
6519        buffer_id: BufferId,
6520        buffer: BufferSnapshot,
6521        range: ExcerptRange<text::Anchor>,
6522        has_trailing_newline: bool,
6523    ) -> Self {
6524        Excerpt {
6525            id,
6526            locator,
6527            max_buffer_row: range.context.end.to_point(&buffer).row,
6528            text_summary: buffer
6529                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6530            buffer_id,
6531            buffer,
6532            range,
6533            has_trailing_newline,
6534        }
6535    }
6536
6537    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6538        let content_start = self.range.context.start.to_offset(&self.buffer);
6539        let chunks_start = content_start + range.start;
6540        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6541
6542        let footer_height = if self.has_trailing_newline
6543            && range.start <= self.text_summary.len
6544            && range.end > self.text_summary.len
6545        {
6546            1
6547        } else {
6548            0
6549        };
6550
6551        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6552
6553        ExcerptChunks {
6554            excerpt_id: self.id,
6555            content_chunks,
6556            footer_height,
6557        }
6558    }
6559
6560    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6561        let content_start = self.range.context.start.to_offset(&self.buffer);
6562        let chunks_start = content_start + range.start;
6563        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6564        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6565        excerpt_chunks.footer_height = if self.has_trailing_newline
6566            && range.start <= self.text_summary.len
6567            && range.end > self.text_summary.len
6568        {
6569            1
6570        } else {
6571            0
6572        };
6573    }
6574
6575    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6576        if text_anchor
6577            .cmp(&self.range.context.start, &self.buffer)
6578            .is_lt()
6579        {
6580            self.range.context.start
6581        } else if text_anchor
6582            .cmp(&self.range.context.end, &self.buffer)
6583            .is_gt()
6584        {
6585            self.range.context.end
6586        } else {
6587            text_anchor
6588        }
6589    }
6590
6591    fn contains(&self, anchor: &Anchor) -> bool {
6592        Some(self.buffer_id) == anchor.buffer_id
6593            && self
6594                .range
6595                .context
6596                .start
6597                .cmp(&anchor.text_anchor, &self.buffer)
6598                .is_le()
6599            && self
6600                .range
6601                .context
6602                .end
6603                .cmp(&anchor.text_anchor, &self.buffer)
6604                .is_ge()
6605    }
6606
6607    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6608    fn buffer_start_offset(&self) -> usize {
6609        self.range.context.start.to_offset(&self.buffer)
6610    }
6611
6612    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6613    fn buffer_end_offset(&self) -> usize {
6614        self.buffer_start_offset() + self.text_summary.len
6615    }
6616}
6617
6618impl<'a> MultiBufferExcerpt<'a> {
6619    pub fn id(&self) -> ExcerptId {
6620        self.excerpt.id
6621    }
6622
6623    pub fn buffer_id(&self) -> BufferId {
6624        self.excerpt.buffer_id
6625    }
6626
6627    pub fn start_anchor(&self) -> Anchor {
6628        Anchor {
6629            buffer_id: Some(self.excerpt.buffer_id),
6630            excerpt_id: self.excerpt.id,
6631            text_anchor: self.excerpt.range.context.start,
6632            diff_base_anchor: None,
6633        }
6634    }
6635
6636    pub fn end_anchor(&self) -> Anchor {
6637        Anchor {
6638            buffer_id: Some(self.excerpt.buffer_id),
6639            excerpt_id: self.excerpt.id,
6640            text_anchor: self.excerpt.range.context.end,
6641            diff_base_anchor: None,
6642        }
6643    }
6644
6645    pub fn buffer(&self) -> &'a BufferSnapshot {
6646        &self.excerpt.buffer
6647    }
6648
6649    pub fn buffer_range(&self) -> Range<usize> {
6650        self.buffer_offset
6651            ..self
6652                .excerpt
6653                .range
6654                .context
6655                .end
6656                .to_offset(&self.excerpt.buffer.text)
6657    }
6658
6659    pub fn start_offset(&self) -> usize {
6660        self.offset
6661    }
6662
6663    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6664    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6665        self.map_range_to_buffer(offset..offset).start
6666    }
6667
6668    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6669    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6670        self.diff_transforms
6671            .seek(&OutputDimension(range.start), Bias::Right, &());
6672        let start = self.map_offset_to_buffer_internal(range.start);
6673        let end = if range.end > range.start {
6674            self.diff_transforms
6675                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6676            self.map_offset_to_buffer_internal(range.end)
6677        } else {
6678            start
6679        };
6680        start..end
6681    }
6682
6683    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6684        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6685        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6686            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6687        };
6688        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6689        self.buffer_offset + offset_in_excerpt
6690    }
6691
6692    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6693    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6694        self.map_range_from_buffer(buffer_offset..buffer_offset)
6695            .start
6696    }
6697
6698    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6699    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6700        if buffer_range.start < self.buffer_offset {
6701            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6702            return buffer_range;
6703        }
6704        let overshoot = buffer_range.start - self.buffer_offset;
6705        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6706        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6707        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6708            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6709            return buffer_range;
6710        }
6711        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6712        let start = self.diff_transforms.start().0 .0 + overshoot;
6713
6714        let end = if buffer_range.end > buffer_range.start {
6715            let overshoot = buffer_range.end - self.buffer_offset;
6716            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6717            self.diff_transforms
6718                .seek_forward(&excerpt_offset, Bias::Right, &());
6719            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6720            self.diff_transforms.start().0 .0 + overshoot
6721        } else {
6722            start
6723        };
6724
6725        start..end
6726    }
6727
6728    /// Returns true if the entirety of the given range is in the buffer's excerpt
6729    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6730        range.start >= self.excerpt.buffer_start_offset()
6731            && range.end <= self.excerpt.buffer_end_offset()
6732    }
6733
6734    pub fn max_buffer_row(&self) -> u32 {
6735        self.excerpt.max_buffer_row
6736    }
6737}
6738
6739impl ExcerptId {
6740    pub fn min() -> Self {
6741        Self(0)
6742    }
6743
6744    pub fn max() -> Self {
6745        Self(usize::MAX)
6746    }
6747
6748    pub fn to_proto(&self) -> u64 {
6749        self.0 as _
6750    }
6751
6752    pub fn from_proto(proto: u64) -> Self {
6753        Self(proto as _)
6754    }
6755
6756    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6757        let a = snapshot.excerpt_locator_for_id(*self);
6758        let b = snapshot.excerpt_locator_for_id(*other);
6759        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6760    }
6761}
6762
6763impl From<ExcerptId> for usize {
6764    fn from(val: ExcerptId) -> Self {
6765        val.0
6766    }
6767}
6768
6769impl fmt::Debug for Excerpt {
6770    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6771        f.debug_struct("Excerpt")
6772            .field("id", &self.id)
6773            .field("locator", &self.locator)
6774            .field("buffer_id", &self.buffer_id)
6775            .field("range", &self.range)
6776            .field("text_summary", &self.text_summary)
6777            .field("has_trailing_newline", &self.has_trailing_newline)
6778            .finish()
6779    }
6780}
6781
6782impl sum_tree::Item for Excerpt {
6783    type Summary = ExcerptSummary;
6784
6785    fn summary(&self, _cx: &()) -> Self::Summary {
6786        let mut text = self.text_summary;
6787        if self.has_trailing_newline {
6788            text += TextSummary::from("\n");
6789        }
6790        ExcerptSummary {
6791            excerpt_id: self.id,
6792            excerpt_locator: self.locator.clone(),
6793            widest_line_number: self.max_buffer_row,
6794            text,
6795        }
6796    }
6797}
6798
6799impl sum_tree::Item for ExcerptIdMapping {
6800    type Summary = ExcerptId;
6801
6802    fn summary(&self, _cx: &()) -> Self::Summary {
6803        self.id
6804    }
6805}
6806
6807impl sum_tree::KeyedItem for ExcerptIdMapping {
6808    type Key = ExcerptId;
6809
6810    fn key(&self) -> Self::Key {
6811        self.id
6812    }
6813}
6814
6815impl DiffTransform {
6816    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6817        match self {
6818            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6819            DiffTransform::BufferContent {
6820                inserted_hunk_info, ..
6821            } => *inserted_hunk_info,
6822        }
6823    }
6824}
6825
6826impl sum_tree::Item for DiffTransform {
6827    type Summary = DiffTransformSummary;
6828
6829    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6830        match self {
6831            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6832                input: *summary,
6833                output: *summary,
6834            },
6835            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6836                input: TextSummary::default(),
6837                output: *summary,
6838            },
6839        }
6840    }
6841}
6842
6843impl DiffTransformSummary {
6844    fn excerpt_len(&self) -> ExcerptOffset {
6845        ExcerptOffset::new(self.input.len)
6846    }
6847}
6848
6849impl sum_tree::Summary for DiffTransformSummary {
6850    type Context = ();
6851
6852    fn zero(_: &Self::Context) -> Self {
6853        DiffTransformSummary {
6854            input: TextSummary::default(),
6855            output: TextSummary::default(),
6856        }
6857    }
6858
6859    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6860        self.input += &summary.input;
6861        self.output += &summary.output;
6862    }
6863}
6864
6865impl sum_tree::Summary for ExcerptId {
6866    type Context = ();
6867
6868    fn zero(_cx: &()) -> Self {
6869        Default::default()
6870    }
6871
6872    fn add_summary(&mut self, other: &Self, _: &()) {
6873        *self = *other;
6874    }
6875}
6876
6877impl sum_tree::Summary for ExcerptSummary {
6878    type Context = ();
6879
6880    fn zero(_cx: &()) -> Self {
6881        Default::default()
6882    }
6883
6884    fn add_summary(&mut self, summary: &Self, _: &()) {
6885        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6886        self.excerpt_locator = summary.excerpt_locator.clone();
6887        self.text.add_summary(&summary.text, &());
6888        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6889    }
6890}
6891
6892impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6893    fn zero(_cx: &()) -> Self {
6894        Default::default()
6895    }
6896
6897    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6898        self.value += summary.text.len;
6899    }
6900}
6901
6902impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6903    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6904        Ord::cmp(&self.value, &cursor_location.text.len)
6905    }
6906}
6907
6908impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6909    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6910        Ord::cmp(&Some(self), cursor_location)
6911    }
6912}
6913
6914impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6915    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6916        Ord::cmp(self, &cursor_location.excerpt_locator)
6917    }
6918}
6919
6920impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6921    fn zero(_cx: &()) -> Self {
6922        Default::default()
6923    }
6924
6925    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6926        self.value += summary.text.lines;
6927    }
6928}
6929
6930impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6931    for ExcerptDimension<D>
6932{
6933    fn zero(_: &()) -> Self {
6934        ExcerptDimension(D::default())
6935    }
6936
6937    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6938        self.0.add_assign(&D::from_text_summary(&summary.text))
6939    }
6940}
6941
6942impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6943    fn zero(_cx: &()) -> Self {
6944        Default::default()
6945    }
6946
6947    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6948        *self = Some(&summary.excerpt_locator);
6949    }
6950}
6951
6952impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6953    fn zero(_cx: &()) -> Self {
6954        Default::default()
6955    }
6956
6957    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6958        *self = Some(summary.excerpt_id);
6959    }
6960}
6961
6962#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6963struct ExcerptDimension<T>(T);
6964
6965#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6966struct OutputDimension<T>(T);
6967
6968impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6969    fn zero(_: &()) -> Self {
6970        ExcerptOffset::new(0)
6971    }
6972
6973    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6974        self.value += summary.input.len;
6975    }
6976}
6977
6978impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6979    fn zero(_: &()) -> Self {
6980        ExcerptPoint::new(0, 0)
6981    }
6982
6983    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6984        self.value += summary.input.lines;
6985    }
6986}
6987
6988impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6989    for ExcerptDimension<D>
6990{
6991    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6992        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6993    }
6994}
6995
6996impl<D: TextDimension + Ord>
6997    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6998    for ExcerptDimension<D>
6999{
7000    fn cmp(
7001        &self,
7002        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7003        _: &(),
7004    ) -> cmp::Ordering {
7005        Ord::cmp(&self.0, &cursor_location.1 .0)
7006    }
7007}
7008
7009impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7010    fn zero(_: &()) -> Self {
7011        ExcerptDimension(D::default())
7012    }
7013
7014    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7015        self.0.add_assign(&D::from_text_summary(&summary.input))
7016    }
7017}
7018
7019impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7020    fn zero(_: &()) -> Self {
7021        OutputDimension(D::default())
7022    }
7023
7024    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7025        self.0.add_assign(&D::from_text_summary(&summary.output))
7026    }
7027}
7028
7029impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7030    fn zero(_: &()) -> Self {
7031        TextSummary::default()
7032    }
7033
7034    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7035        *self += summary.output
7036    }
7037}
7038
7039impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7040    fn zero(_: &()) -> Self {
7041        0
7042    }
7043
7044    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7045        *self += summary.output.len
7046    }
7047}
7048
7049impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7050    fn zero(_: &()) -> Self {
7051        Point::new(0, 0)
7052    }
7053
7054    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7055        *self += summary.output.lines
7056    }
7057}
7058
7059impl MultiBufferRows<'_> {
7060    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7061        self.point = Point::new(row, 0);
7062        self.cursor.seek(&self.point);
7063    }
7064}
7065
7066impl Iterator for MultiBufferRows<'_> {
7067    type Item = RowInfo;
7068
7069    fn next(&mut self) -> Option<Self::Item> {
7070        if self.is_empty && self.point.row == 0 {
7071            self.point += Point::new(1, 0);
7072            return Some(RowInfo {
7073                buffer_id: None,
7074                buffer_row: Some(0),
7075                multibuffer_row: Some(MultiBufferRow(0)),
7076                diff_status: None,
7077            });
7078        }
7079
7080        let mut region = self.cursor.region()?;
7081        while self.point >= region.range.end {
7082            self.cursor.next();
7083            if let Some(next_region) = self.cursor.region() {
7084                region = next_region;
7085            } else {
7086                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7087                    let multibuffer_row = MultiBufferRow(self.point.row);
7088                    self.point += Point::new(1, 0);
7089                    let last_excerpt = self
7090                        .cursor
7091                        .excerpts
7092                        .item()
7093                        .or(self.cursor.excerpts.prev_item())?;
7094                    let last_row = last_excerpt
7095                        .range
7096                        .context
7097                        .end
7098                        .to_point(&last_excerpt.buffer)
7099                        .row;
7100                    return Some(RowInfo {
7101                        buffer_id: Some(last_excerpt.buffer_id),
7102                        buffer_row: Some(last_row),
7103                        multibuffer_row: Some(multibuffer_row),
7104                        diff_status: None,
7105                    });
7106                } else {
7107                    return None;
7108                }
7109            };
7110        }
7111
7112        let overshoot = self.point - region.range.start;
7113        let buffer_point = region.buffer_range.start + overshoot;
7114        let result = Some(RowInfo {
7115            buffer_id: Some(region.buffer.remote_id()),
7116            buffer_row: Some(buffer_point.row),
7117            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7118            diff_status: region
7119                .diff_hunk_status
7120                .filter(|_| self.point < region.range.end),
7121        });
7122        self.point += Point::new(1, 0);
7123        result
7124    }
7125}
7126
7127impl<'a> MultiBufferChunks<'a> {
7128    pub fn offset(&self) -> usize {
7129        self.range.start
7130    }
7131
7132    pub fn seek(&mut self, range: Range<usize>) {
7133        self.diff_transforms.seek(&range.end, Bias::Right, &());
7134        let mut excerpt_end = self.diff_transforms.start().1;
7135        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7136            let overshoot = range.end - self.diff_transforms.start().0;
7137            excerpt_end.value += overshoot;
7138        }
7139
7140        self.diff_transforms.seek(&range.start, Bias::Right, &());
7141        let mut excerpt_start = self.diff_transforms.start().1;
7142        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7143            let overshoot = range.start - self.diff_transforms.start().0;
7144            excerpt_start.value += overshoot;
7145        }
7146
7147        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7148        self.buffer_chunk.take();
7149        self.range = range;
7150    }
7151
7152    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7153        self.excerpt_offset_range = new_range.clone();
7154        self.excerpts.seek(&new_range.start, Bias::Right, &());
7155        if let Some(excerpt) = self.excerpts.item() {
7156            let excerpt_start = *self.excerpts.start();
7157            if let Some(excerpt_chunks) = self
7158                .excerpt_chunks
7159                .as_mut()
7160                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7161            {
7162                excerpt.seek_chunks(
7163                    excerpt_chunks,
7164                    (self.excerpt_offset_range.start - excerpt_start).value
7165                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7166                );
7167            } else {
7168                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7169                    (self.excerpt_offset_range.start - excerpt_start).value
7170                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7171                    self.language_aware,
7172                ));
7173            }
7174        } else {
7175            self.excerpt_chunks = None;
7176        }
7177    }
7178
7179    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7180        loop {
7181            if self.excerpt_offset_range.is_empty() {
7182                return None;
7183            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7184                self.excerpt_offset_range.start.value += chunk.text.len();
7185                return Some(chunk);
7186            } else {
7187                self.excerpts.next(&());
7188                let excerpt = self.excerpts.item()?;
7189                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7190                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7191                    self.language_aware,
7192                ));
7193            }
7194        }
7195    }
7196}
7197
7198impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7199    type Item = &'a str;
7200
7201    fn next(&mut self) -> Option<Self::Item> {
7202        let mut region = self.cursor.region()?;
7203        if self.offset == region.range.start {
7204            self.cursor.prev();
7205            region = self.cursor.region()?;
7206            let start_overshoot = self.start.saturating_sub(region.range.start);
7207            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7208                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7209            ));
7210        }
7211
7212        if self.offset == region.range.end && region.has_trailing_newline {
7213            self.offset -= 1;
7214            Some("\n")
7215        } else {
7216            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7217            self.offset -= chunk.len();
7218            Some(chunk)
7219        }
7220    }
7221}
7222
7223impl<'a> Iterator for MultiBufferChunks<'a> {
7224    type Item = Chunk<'a>;
7225
7226    fn next(&mut self) -> Option<Chunk<'a>> {
7227        if self.range.start >= self.range.end {
7228            return None;
7229        }
7230        if self.range.start == self.diff_transforms.end(&()).0 {
7231            self.diff_transforms.next(&());
7232        }
7233
7234        let diff_transform_start = self.diff_transforms.start().0;
7235        let diff_transform_end = self.diff_transforms.end(&()).0;
7236        debug_assert!(self.range.start < diff_transform_end);
7237
7238        let diff_transform = self.diff_transforms.item()?;
7239        match diff_transform {
7240            DiffTransform::BufferContent { .. } => {
7241                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7242                    chunk
7243                } else {
7244                    let chunk = self.next_excerpt_chunk().unwrap();
7245                    self.buffer_chunk.insert(chunk)
7246                };
7247
7248                let chunk_end = self.range.start + chunk.text.len();
7249                let diff_transform_end = diff_transform_end.min(self.range.end);
7250
7251                if diff_transform_end < chunk_end {
7252                    let (before, after) =
7253                        chunk.text.split_at(diff_transform_end - self.range.start);
7254                    self.range.start = diff_transform_end;
7255                    chunk.text = after;
7256                    Some(Chunk {
7257                        text: before,
7258                        ..chunk.clone()
7259                    })
7260                } else {
7261                    self.range.start = chunk_end;
7262                    self.buffer_chunk.take()
7263                }
7264            }
7265            DiffTransform::DeletedHunk {
7266                buffer_id,
7267                base_text_byte_range,
7268                has_trailing_newline,
7269                ..
7270            } => {
7271                let base_text_start =
7272                    base_text_byte_range.start + self.range.start - diff_transform_start;
7273                let base_text_end =
7274                    base_text_byte_range.start + self.range.end - diff_transform_start;
7275                let base_text_end = base_text_end.min(base_text_byte_range.end);
7276
7277                let mut chunks = if let Some((_, mut chunks)) = self
7278                    .diff_base_chunks
7279                    .take()
7280                    .filter(|(id, _)| id == buffer_id)
7281                {
7282                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7283                    {
7284                        chunks.seek(base_text_start..base_text_end);
7285                    }
7286                    chunks
7287                } else {
7288                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7289                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7290                };
7291
7292                let chunk = if let Some(chunk) = chunks.next() {
7293                    self.range.start += chunk.text.len();
7294                    self.diff_base_chunks = Some((*buffer_id, chunks));
7295                    chunk
7296                } else {
7297                    debug_assert!(has_trailing_newline);
7298                    self.range.start += "\n".len();
7299                    Chunk {
7300                        text: "\n",
7301                        ..Default::default()
7302                    }
7303                };
7304                Some(chunk)
7305            }
7306        }
7307    }
7308}
7309
7310impl MultiBufferBytes<'_> {
7311    fn consume(&mut self, len: usize) {
7312        self.range.start += len;
7313        self.chunk = &self.chunk[len..];
7314
7315        if !self.range.is_empty() && self.chunk.is_empty() {
7316            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7317                self.chunk = chunk;
7318            } else if self.has_trailing_newline {
7319                self.has_trailing_newline = false;
7320                self.chunk = b"\n";
7321            } else {
7322                self.cursor.next();
7323                if let Some(region) = self.cursor.region() {
7324                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7325                        region.buffer_range.start
7326                            ..(region.buffer_range.start + self.range.end - region.range.start)
7327                                .min(region.buffer_range.end),
7328                    );
7329                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7330                    self.excerpt_bytes = Some(excerpt_bytes);
7331                    self.has_trailing_newline =
7332                        region.has_trailing_newline && self.range.end >= region.range.end;
7333                    if self.chunk.is_empty() && self.has_trailing_newline {
7334                        self.has_trailing_newline = false;
7335                        self.chunk = b"\n";
7336                    }
7337                }
7338            }
7339        }
7340    }
7341}
7342
7343impl<'a> Iterator for MultiBufferBytes<'a> {
7344    type Item = &'a [u8];
7345
7346    fn next(&mut self) -> Option<Self::Item> {
7347        let chunk = self.chunk;
7348        if chunk.is_empty() {
7349            None
7350        } else {
7351            self.consume(chunk.len());
7352            Some(chunk)
7353        }
7354    }
7355}
7356
7357impl io::Read for MultiBufferBytes<'_> {
7358    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7359        let len = cmp::min(buf.len(), self.chunk.len());
7360        buf[..len].copy_from_slice(&self.chunk[..len]);
7361        if len > 0 {
7362            self.consume(len);
7363        }
7364        Ok(len)
7365    }
7366}
7367
7368impl io::Read for ReversedMultiBufferBytes<'_> {
7369    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7370        let len = cmp::min(buf.len(), self.chunk.len());
7371        buf[..len].copy_from_slice(&self.chunk[..len]);
7372        buf[..len].reverse();
7373        if len > 0 {
7374            self.range.end -= len;
7375            self.chunk = &self.chunk[..self.chunk.len() - len];
7376            if !self.range.is_empty() && self.chunk.is_empty() {
7377                if let Some(chunk) = self.chunks.next() {
7378                    self.chunk = chunk.as_bytes();
7379                }
7380            }
7381        }
7382        Ok(len)
7383    }
7384}
7385
7386impl<'a> Iterator for ExcerptChunks<'a> {
7387    type Item = Chunk<'a>;
7388
7389    fn next(&mut self) -> Option<Self::Item> {
7390        if let Some(chunk) = self.content_chunks.next() {
7391            return Some(chunk);
7392        }
7393
7394        if self.footer_height > 0 {
7395            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7396            self.footer_height = 0;
7397            return Some(Chunk {
7398                text,
7399                ..Default::default()
7400            });
7401        }
7402
7403        None
7404    }
7405}
7406
7407impl ToOffset for Point {
7408    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7409        snapshot.point_to_offset(*self)
7410    }
7411}
7412
7413impl ToOffset for usize {
7414    #[track_caller]
7415    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7416        assert!(*self <= snapshot.len(), "offset is out of range");
7417        *self
7418    }
7419}
7420
7421impl ToOffset for OffsetUtf16 {
7422    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7423        snapshot.offset_utf16_to_offset(*self)
7424    }
7425}
7426
7427impl ToOffset for PointUtf16 {
7428    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7429        snapshot.point_utf16_to_offset(*self)
7430    }
7431}
7432
7433impl ToOffsetUtf16 for OffsetUtf16 {
7434    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7435        *self
7436    }
7437}
7438
7439impl ToOffsetUtf16 for usize {
7440    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7441        snapshot.offset_to_offset_utf16(*self)
7442    }
7443}
7444
7445impl ToPoint for usize {
7446    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7447        snapshot.offset_to_point(*self)
7448    }
7449}
7450
7451impl ToPoint for Point {
7452    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7453        *self
7454    }
7455}
7456
7457impl ToPointUtf16 for usize {
7458    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7459        snapshot.offset_to_point_utf16(*self)
7460    }
7461}
7462
7463impl ToPointUtf16 for Point {
7464    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7465        snapshot.point_to_point_utf16(*self)
7466    }
7467}
7468
7469impl ToPointUtf16 for PointUtf16 {
7470    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7471        *self
7472    }
7473}
7474
7475impl From<ExcerptId> for EntityId {
7476    fn from(id: ExcerptId) -> Self {
7477        EntityId::from(id.0 as u64)
7478    }
7479}
7480
7481pub fn build_excerpt_ranges<T>(
7482    buffer: &BufferSnapshot,
7483    ranges: &[Range<T>],
7484    context_line_count: u32,
7485) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7486where
7487    T: text::ToPoint,
7488{
7489    let max_point = buffer.max_point();
7490    let mut range_counts = Vec::new();
7491    let mut excerpt_ranges = Vec::new();
7492    let mut range_iter = ranges
7493        .iter()
7494        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7495        .peekable();
7496    while let Some(range) = range_iter.next() {
7497        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7498        let row = (range.end.row + context_line_count).min(max_point.row);
7499        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7500
7501        let mut ranges_in_excerpt = 1;
7502
7503        while let Some(next_range) = range_iter.peek() {
7504            if next_range.start.row <= excerpt_end.row + context_line_count {
7505                let row = (next_range.end.row + context_line_count).min(max_point.row);
7506                excerpt_end = Point::new(row, buffer.line_len(row));
7507
7508                ranges_in_excerpt += 1;
7509                range_iter.next();
7510            } else {
7511                break;
7512            }
7513        }
7514
7515        excerpt_ranges.push(ExcerptRange {
7516            context: excerpt_start..excerpt_end,
7517            primary: Some(range),
7518        });
7519        range_counts.push(ranges_in_excerpt);
7520    }
7521
7522    (excerpt_ranges, range_counts)
7523}