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