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 clock::ReplicaId;
  11use collections::{BTreeMap, Bound, HashMap, HashSet};
  12use futures::{channel::mpsc, SinkExt};
  13use git::diff::DiffHunkStatus;
  14use gpui::{App, Context, Entity, EntityId, EventEmitter, Task};
  15use itertools::Itertools;
  16use language::{
  17    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  18    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  19    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  20    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  21    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  22    Unclipped,
  23};
  24use project::buffer_store::{BufferChangeSet, BufferChangeSetEvent};
  25use rope::DimensionPair;
  26use smallvec::SmallVec;
  27use smol::future::yield_now;
  28use std::{
  29    any::type_name,
  30    borrow::Cow,
  31    cell::{Ref, RefCell, RefMut},
  32    cmp, fmt,
  33    future::Future,
  34    io,
  35    iter::{self, FromIterator},
  36    mem,
  37    ops::{Range, RangeBounds, Sub},
  38    str,
  39    sync::Arc,
  40    time::{Duration, Instant},
  41};
  42use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  43use text::{
  44    locator::Locator,
  45    subscription::{Subscription, Topic},
  46    BufferId, Edit, LineIndent, TextSummary,
  47};
  48use theme::SyntaxTheme;
  49use util::post_inc;
  50
  51#[cfg(any(test, feature = "test-support"))]
  52use gpui::AppContext as _;
  53
  54const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  55
  56#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  57pub struct ExcerptId(usize);
  58
  59/// One or more [`Buffers`](Buffer) being edited in a single view.
  60///
  61/// See <https://zed.dev/features#multi-buffers>
  62pub struct MultiBuffer {
  63    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  64    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  65    snapshot: RefCell<MultiBufferSnapshot>,
  66    /// Contains the state of the buffers being edited
  67    buffers: RefCell<HashMap<BufferId, BufferState>>,
  68    diff_bases: HashMap<BufferId, ChangeSetState>,
  69    all_diff_hunks_expanded: bool,
  70    subscriptions: Topic,
  71    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  72    singleton: bool,
  73    history: History,
  74    title: Option<String>,
  75    capability: Capability,
  76}
  77
  78#[derive(Clone, Debug, PartialEq, Eq)]
  79pub enum Event {
  80    ExcerptsAdded {
  81        buffer: Entity<Buffer>,
  82        predecessor: ExcerptId,
  83        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  84    },
  85    ExcerptsRemoved {
  86        ids: Vec<ExcerptId>,
  87    },
  88    ExcerptsExpanded {
  89        ids: Vec<ExcerptId>,
  90    },
  91    ExcerptsEdited {
  92        ids: Vec<ExcerptId>,
  93    },
  94    DiffHunksToggled,
  95    Edited {
  96        singleton_buffer_edited: bool,
  97        edited_buffer: Option<Entity<Buffer>>,
  98    },
  99    TransactionUndone {
 100        transaction_id: TransactionId,
 101    },
 102    Reloaded,
 103    ReloadNeeded,
 104
 105    LanguageChanged(BufferId),
 106    CapabilityChanged,
 107    Reparsed(BufferId),
 108    Saved,
 109    FileHandleChanged,
 110    Closed,
 111    Discarded,
 112    DirtyChanged,
 113    DiagnosticsUpdated,
 114}
 115
 116/// A diff hunk, representing a range of consequent lines in a multibuffer.
 117#[derive(Debug, Clone, PartialEq, Eq)]
 118pub struct MultiBufferDiffHunk {
 119    /// The row range in the multibuffer where this diff hunk appears.
 120    pub row_range: Range<MultiBufferRow>,
 121    /// The buffer ID that this hunk belongs to.
 122    pub buffer_id: BufferId,
 123    /// The range of the underlying buffer that this hunk corresponds to.
 124    pub buffer_range: Range<text::Anchor>,
 125    /// The excerpt that contains the diff hunk.
 126    pub excerpt_id: ExcerptId,
 127    /// The range within the buffer's diff base that this hunk corresponds to.
 128    pub diff_base_byte_range: Range<usize>,
 129}
 130
 131impl MultiBufferDiffHunk {
 132    pub fn status(&self) -> DiffHunkStatus {
 133        if self.buffer_range.start == self.buffer_range.end {
 134            DiffHunkStatus::Removed
 135        } else if self.diff_base_byte_range.is_empty() {
 136            DiffHunkStatus::Added
 137        } else {
 138            DiffHunkStatus::Modified
 139        }
 140    }
 141}
 142
 143pub type MultiBufferPoint = Point;
 144type ExcerptOffset = TypedOffset<Excerpt>;
 145type ExcerptPoint = TypedPoint<Excerpt>;
 146
 147#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 148#[serde(transparent)]
 149pub struct MultiBufferRow(pub u32);
 150
 151impl MultiBufferRow {
 152    pub const MIN: Self = Self(0);
 153    pub const MAX: Self = Self(u32::MAX);
 154}
 155
 156impl std::ops::Add<usize> for MultiBufferRow {
 157    type Output = Self;
 158
 159    fn add(self, rhs: usize) -> Self::Output {
 160        MultiBufferRow(self.0 + rhs as u32)
 161    }
 162}
 163
 164#[derive(Clone)]
 165struct History {
 166    next_transaction_id: TransactionId,
 167    undo_stack: Vec<Transaction>,
 168    redo_stack: Vec<Transaction>,
 169    transaction_depth: usize,
 170    group_interval: Duration,
 171}
 172
 173#[derive(Clone)]
 174struct Transaction {
 175    id: TransactionId,
 176    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 177    first_edit_at: Instant,
 178    last_edit_at: Instant,
 179    suppress_grouping: bool,
 180}
 181
 182pub trait ToOffset: 'static + fmt::Debug {
 183    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 184}
 185
 186pub trait ToOffsetUtf16: 'static + fmt::Debug {
 187    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 188}
 189
 190pub trait ToPoint: 'static + fmt::Debug {
 191    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 192}
 193
 194pub trait ToPointUtf16: 'static + fmt::Debug {
 195    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 196}
 197
 198struct BufferState {
 199    buffer: Entity<Buffer>,
 200    last_version: clock::Global,
 201    last_non_text_state_update_count: usize,
 202    excerpts: Vec<Locator>,
 203    _subscriptions: [gpui::Subscription; 2],
 204}
 205
 206struct ChangeSetState {
 207    change_set: Entity<BufferChangeSet>,
 208    _subscription: gpui::Subscription,
 209}
 210
 211/// The contents of a [`MultiBuffer`] at a single point in time.
 212#[derive(Clone, Default)]
 213pub struct MultiBufferSnapshot {
 214    singleton: bool,
 215    excerpts: SumTree<Excerpt>,
 216    excerpt_ids: SumTree<ExcerptIdMapping>,
 217    diffs: TreeMap<BufferId, DiffSnapshot>,
 218    pub diff_transforms: SumTree<DiffTransform>,
 219    trailing_excerpt_update_count: usize,
 220    non_text_state_update_count: usize,
 221    edit_count: usize,
 222    is_dirty: bool,
 223    has_deleted_file: bool,
 224    has_conflict: bool,
 225    show_headers: bool,
 226}
 227
 228#[derive(Debug, Clone)]
 229pub enum DiffTransform {
 230    BufferContent {
 231        summary: TextSummary,
 232        inserted_hunk_anchor: Option<(ExcerptId, text::Anchor)>,
 233    },
 234    DeletedHunk {
 235        summary: TextSummary,
 236        buffer_id: BufferId,
 237        hunk_anchor: (ExcerptId, text::Anchor),
 238        base_text_byte_range: Range<usize>,
 239        has_trailing_newline: bool,
 240    },
 241}
 242
 243#[derive(Clone)]
 244struct DiffSnapshot {
 245    diff: git::diff::BufferDiff,
 246    base_text: language::BufferSnapshot,
 247}
 248
 249#[derive(Clone)]
 250pub struct ExcerptInfo {
 251    pub id: ExcerptId,
 252    pub buffer: BufferSnapshot,
 253    pub buffer_id: BufferId,
 254    pub range: ExcerptRange<text::Anchor>,
 255    pub end_row: MultiBufferRow,
 256}
 257
 258impl std::fmt::Debug for ExcerptInfo {
 259    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 260        f.debug_struct(type_name::<Self>())
 261            .field("id", &self.id)
 262            .field("buffer_id", &self.buffer_id)
 263            .field("path", &self.buffer.file().map(|f| f.path()))
 264            .field("range", &self.range)
 265            .finish()
 266    }
 267}
 268
 269/// A boundary between [`Excerpt`]s in a [`MultiBuffer`]
 270#[derive(Debug)]
 271pub struct ExcerptBoundary {
 272    pub prev: Option<ExcerptInfo>,
 273    pub next: Option<ExcerptInfo>,
 274    /// The row in the `MultiBuffer` where the boundary is located
 275    pub row: MultiBufferRow,
 276}
 277
 278impl ExcerptBoundary {
 279    pub fn starts_new_buffer(&self) -> bool {
 280        match (self.prev.as_ref(), self.next.as_ref()) {
 281            (None, _) => true,
 282            (Some(_), None) => false,
 283            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 284        }
 285    }
 286}
 287
 288#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 289pub struct RowInfo {
 290    pub buffer_row: Option<u32>,
 291    pub multibuffer_row: Option<MultiBufferRow>,
 292    pub diff_status: Option<git::diff::DiffHunkStatus>,
 293}
 294
 295/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 296#[derive(Clone)]
 297struct Excerpt {
 298    /// The unique identifier for this excerpt
 299    id: ExcerptId,
 300    /// The location of the excerpt in the [`MultiBuffer`]
 301    locator: Locator,
 302    /// The buffer being excerpted
 303    buffer_id: BufferId,
 304    /// A snapshot of the buffer being excerpted
 305    buffer: BufferSnapshot,
 306    /// The range of the buffer to be shown in the excerpt
 307    range: ExcerptRange<text::Anchor>,
 308    /// The last row in the excerpted slice of the buffer
 309    max_buffer_row: BufferRow,
 310    /// A summary of the text in the excerpt
 311    text_summary: TextSummary,
 312    has_trailing_newline: bool,
 313}
 314
 315/// A public view into an [`Excerpt`] in a [`MultiBuffer`].
 316///
 317/// Contains methods for getting the [`Buffer`] of the excerpt,
 318/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 319#[derive(Clone)]
 320pub struct MultiBufferExcerpt<'a> {
 321    excerpt: &'a Excerpt,
 322    diff_transforms:
 323        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 324    offset: usize,
 325    excerpt_offset: ExcerptDimension<usize>,
 326    buffer_offset: usize,
 327}
 328
 329#[derive(Clone, Debug)]
 330struct ExcerptIdMapping {
 331    id: ExcerptId,
 332    locator: Locator,
 333}
 334
 335/// A range of text from a single [`Buffer`], to be shown as an [`Excerpt`].
 336/// These ranges are relative to the buffer itself
 337#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 338pub struct ExcerptRange<T> {
 339    /// The full range of text to be shown in the excerpt.
 340    pub context: Range<T>,
 341    /// The primary range of text to be highlighted in the excerpt.
 342    /// In a multi-buffer search, this would be the text that matched the search
 343    pub primary: Option<Range<T>>,
 344}
 345
 346#[derive(Clone, Debug, Default)]
 347pub struct ExcerptSummary {
 348    excerpt_id: ExcerptId,
 349    /// The location of the last [`Excerpt`] being summarized
 350    excerpt_locator: Locator,
 351    widest_line_number: u32,
 352    text: TextSummary,
 353}
 354
 355#[derive(Debug, Clone)]
 356pub struct DiffTransformSummary {
 357    input: TextSummary,
 358    output: TextSummary,
 359}
 360
 361#[derive(Clone)]
 362pub struct MultiBufferRows<'a> {
 363    point: Point,
 364    is_empty: bool,
 365    cursor: MultiBufferCursor<'a, Point>,
 366}
 367
 368pub struct MultiBufferChunks<'a> {
 369    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 370    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 371    diffs: &'a TreeMap<BufferId, DiffSnapshot>,
 372    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 373    buffer_chunk: Option<Chunk<'a>>,
 374    range: Range<usize>,
 375    excerpt_offset_range: Range<ExcerptOffset>,
 376    excerpt_chunks: Option<ExcerptChunks<'a>>,
 377    language_aware: bool,
 378}
 379
 380pub struct ReversedMultiBufferChunks<'a> {
 381    cursor: MultiBufferCursor<'a, usize>,
 382    current_chunks: Option<rope::Chunks<'a>>,
 383    start: usize,
 384    offset: usize,
 385}
 386
 387pub struct MultiBufferBytes<'a> {
 388    range: Range<usize>,
 389    cursor: MultiBufferCursor<'a, usize>,
 390    excerpt_bytes: Option<text::Bytes<'a>>,
 391    has_trailing_newline: bool,
 392    chunk: &'a [u8],
 393}
 394
 395pub struct ReversedMultiBufferBytes<'a> {
 396    range: Range<usize>,
 397    chunks: ReversedMultiBufferChunks<'a>,
 398    chunk: &'a [u8],
 399}
 400
 401#[derive(Clone)]
 402struct MultiBufferCursor<'a, D: TextDimension> {
 403    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 404    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 405    diffs: &'a TreeMap<BufferId, DiffSnapshot>,
 406    cached_region: Option<MultiBufferRegion<'a, D>>,
 407}
 408
 409#[derive(Clone)]
 410struct MultiBufferRegion<'a, D: TextDimension> {
 411    buffer: &'a BufferSnapshot,
 412    is_main_buffer: bool,
 413    is_inserted_hunk: bool,
 414    excerpt: &'a Excerpt,
 415    buffer_range: Range<D>,
 416    range: Range<D>,
 417    has_trailing_newline: bool,
 418}
 419
 420struct ExcerptChunks<'a> {
 421    excerpt_id: ExcerptId,
 422    content_chunks: BufferChunks<'a>,
 423    footer_height: usize,
 424}
 425
 426#[derive(Debug)]
 427struct BufferEdit {
 428    range: Range<usize>,
 429    new_text: Arc<str>,
 430    is_insertion: bool,
 431    original_indent_column: u32,
 432    excerpt_id: ExcerptId,
 433}
 434
 435#[derive(Clone, Copy, Debug, PartialEq)]
 436enum DiffChangeKind {
 437    BufferEdited,
 438    DiffUpdated { base_changed: bool },
 439    ExpandOrCollapseHunks { expand: bool },
 440}
 441
 442#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 443pub enum ExpandExcerptDirection {
 444    Up,
 445    Down,
 446    UpAndDown,
 447}
 448
 449impl ExpandExcerptDirection {
 450    pub fn should_expand_up(&self) -> bool {
 451        match self {
 452            ExpandExcerptDirection::Up => true,
 453            ExpandExcerptDirection::Down => false,
 454            ExpandExcerptDirection::UpAndDown => true,
 455        }
 456    }
 457
 458    pub fn should_expand_down(&self) -> bool {
 459        match self {
 460            ExpandExcerptDirection::Up => false,
 461            ExpandExcerptDirection::Down => true,
 462            ExpandExcerptDirection::UpAndDown => true,
 463        }
 464    }
 465}
 466
 467#[derive(Clone, Debug, PartialEq)]
 468pub struct IndentGuide {
 469    pub buffer_id: BufferId,
 470    pub start_row: MultiBufferRow,
 471    pub end_row: MultiBufferRow,
 472    pub depth: u32,
 473    pub tab_size: u32,
 474    pub settings: IndentGuideSettings,
 475}
 476
 477impl IndentGuide {
 478    pub fn indent_level(&self) -> u32 {
 479        self.depth * self.tab_size
 480    }
 481}
 482
 483impl MultiBuffer {
 484    pub fn new(capability: Capability) -> Self {
 485        Self {
 486            snapshot: RefCell::new(MultiBufferSnapshot {
 487                show_headers: true,
 488                ..MultiBufferSnapshot::default()
 489            }),
 490            buffers: RefCell::default(),
 491            diff_bases: HashMap::default(),
 492            all_diff_hunks_expanded: false,
 493            subscriptions: Topic::default(),
 494            singleton: false,
 495            capability,
 496            title: None,
 497            history: History {
 498                next_transaction_id: clock::Lamport::default(),
 499                undo_stack: Vec::new(),
 500                redo_stack: Vec::new(),
 501                transaction_depth: 0,
 502                group_interval: Duration::from_millis(300),
 503            },
 504        }
 505    }
 506
 507    pub fn without_headers(capability: Capability) -> Self {
 508        Self {
 509            snapshot: Default::default(),
 510            buffers: Default::default(),
 511            diff_bases: HashMap::default(),
 512            all_diff_hunks_expanded: false,
 513            subscriptions: Default::default(),
 514            singleton: false,
 515            capability,
 516            history: History {
 517                next_transaction_id: Default::default(),
 518                undo_stack: Default::default(),
 519                redo_stack: Default::default(),
 520                transaction_depth: 0,
 521                group_interval: Duration::from_millis(300),
 522            },
 523            title: Default::default(),
 524        }
 525    }
 526
 527    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 528        let mut buffers = HashMap::default();
 529        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 530            buffers.insert(
 531                *buffer_id,
 532                BufferState {
 533                    buffer: buffer_state.buffer.clone(),
 534                    last_version: buffer_state.last_version.clone(),
 535                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 536                    excerpts: buffer_state.excerpts.clone(),
 537                    _subscriptions: [
 538                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 539                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 540                    ],
 541                },
 542            );
 543        }
 544        let mut diff_bases = HashMap::default();
 545        for (buffer_id, change_set_state) in self.diff_bases.iter() {
 546            diff_bases.insert(
 547                *buffer_id,
 548                ChangeSetState {
 549                    _subscription: new_cx.subscribe(
 550                        &change_set_state.change_set,
 551                        |this, change_set, event, cx| match event {
 552                            BufferChangeSetEvent::DiffChanged { changed_range } => {
 553                                this.buffer_diff_changed(change_set, changed_range.clone(), cx)
 554                            }
 555                        },
 556                    ),
 557                    change_set: change_set_state.change_set.clone(),
 558                },
 559            );
 560        }
 561        Self {
 562            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 563            buffers: RefCell::new(buffers),
 564            diff_bases,
 565            all_diff_hunks_expanded: self.all_diff_hunks_expanded,
 566            subscriptions: Default::default(),
 567            singleton: self.singleton,
 568            capability: self.capability,
 569            history: self.history.clone(),
 570            title: self.title.clone(),
 571        }
 572    }
 573
 574    pub fn with_title(mut self, title: String) -> Self {
 575        self.title = Some(title);
 576        self
 577    }
 578
 579    pub fn read_only(&self) -> bool {
 580        self.capability == Capability::ReadOnly
 581    }
 582
 583    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 584        let mut this = Self::new(buffer.read(cx).capability());
 585        this.singleton = true;
 586        this.push_excerpts(
 587            buffer,
 588            [ExcerptRange {
 589                context: text::Anchor::MIN..text::Anchor::MAX,
 590                primary: None,
 591            }],
 592            cx,
 593        );
 594        this.snapshot.borrow_mut().singleton = true;
 595        this
 596    }
 597
 598    /// Returns an up-to-date snapshot of the MultiBuffer.
 599    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 600        self.sync(cx);
 601        self.snapshot.borrow().clone()
 602    }
 603
 604    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 605        self.sync(cx);
 606        self.snapshot.borrow()
 607    }
 608
 609    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 610        if self.singleton {
 611            return Some(
 612                self.buffers
 613                    .borrow()
 614                    .values()
 615                    .next()
 616                    .unwrap()
 617                    .buffer
 618                    .clone(),
 619            );
 620        } else {
 621            None
 622        }
 623    }
 624
 625    pub fn is_singleton(&self) -> bool {
 626        self.singleton
 627    }
 628
 629    pub fn subscribe(&mut self) -> Subscription {
 630        self.subscriptions.subscribe()
 631    }
 632
 633    pub fn is_dirty(&self, cx: &App) -> bool {
 634        self.read(cx).is_dirty()
 635    }
 636
 637    pub fn has_deleted_file(&self, cx: &App) -> bool {
 638        self.read(cx).has_deleted_file()
 639    }
 640
 641    pub fn has_conflict(&self, cx: &App) -> bool {
 642        self.read(cx).has_conflict()
 643    }
 644
 645    // The `is_empty` signature doesn't match what clippy expects
 646    #[allow(clippy::len_without_is_empty)]
 647    pub fn len(&self, cx: &App) -> usize {
 648        self.read(cx).len()
 649    }
 650
 651    pub fn is_empty(&self, cx: &App) -> bool {
 652        self.len(cx) != 0
 653    }
 654
 655    pub fn symbols_containing<T: ToOffset>(
 656        &self,
 657        offset: T,
 658        theme: Option<&SyntaxTheme>,
 659        cx: &App,
 660    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 661        self.read(cx).symbols_containing(offset, theme)
 662    }
 663
 664    pub fn edit<I, S, T>(
 665        &self,
 666        edits: I,
 667        autoindent_mode: Option<AutoindentMode>,
 668        cx: &mut Context<Self>,
 669    ) where
 670        I: IntoIterator<Item = (Range<S>, T)>,
 671        S: ToOffset,
 672        T: Into<Arc<str>>,
 673    {
 674        let snapshot = self.read(cx);
 675        let edits = edits
 676            .into_iter()
 677            .map(|(range, new_text)| {
 678                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 679                if range.start > range.end {
 680                    mem::swap(&mut range.start, &mut range.end);
 681                }
 682                (range, new_text.into())
 683            })
 684            .collect::<Vec<_>>();
 685
 686        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 687
 688        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 689        fn edit_internal(
 690            this: &MultiBuffer,
 691            snapshot: Ref<MultiBufferSnapshot>,
 692            edits: Vec<(Range<usize>, Arc<str>)>,
 693            mut autoindent_mode: Option<AutoindentMode>,
 694            cx: &mut Context<MultiBuffer>,
 695        ) {
 696            if this.read_only() || this.buffers.borrow().is_empty() {
 697                return;
 698            }
 699
 700            let original_indent_columns = match &mut autoindent_mode {
 701                Some(AutoindentMode::Block {
 702                    original_indent_columns,
 703                }) => mem::take(original_indent_columns),
 704                _ => Default::default(),
 705            };
 706
 707            let (buffer_edits, edited_excerpt_ids) =
 708                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 709            drop(snapshot);
 710
 711            for (buffer_id, mut edits) in buffer_edits {
 712                edits.sort_by_key(|edit| edit.range.start);
 713                this.buffers.borrow()[&buffer_id]
 714                    .buffer
 715                    .update(cx, |buffer, cx| {
 716                        let mut edits = edits.into_iter().peekable();
 717                        let mut insertions = Vec::new();
 718                        let mut original_indent_columns = Vec::new();
 719                        let mut deletions = Vec::new();
 720                        let empty_str: Arc<str> = Arc::default();
 721                        while let Some(BufferEdit {
 722                            mut range,
 723                            mut new_text,
 724                            mut is_insertion,
 725                            original_indent_column,
 726                            excerpt_id,
 727                        }) = edits.next()
 728                        {
 729                            while let Some(BufferEdit {
 730                                range: next_range,
 731                                is_insertion: next_is_insertion,
 732                                new_text: next_new_text,
 733                                excerpt_id: next_excerpt_id,
 734                                ..
 735                            }) = edits.peek()
 736                            {
 737                                if range.end >= next_range.start {
 738                                    range.end = cmp::max(next_range.end, range.end);
 739                                    is_insertion |= *next_is_insertion;
 740                                    if excerpt_id == *next_excerpt_id {
 741                                        new_text = format!("{new_text}{next_new_text}").into();
 742                                    }
 743                                    edits.next();
 744                                } else {
 745                                    break;
 746                                }
 747                            }
 748
 749                            if is_insertion {
 750                                original_indent_columns.push(original_indent_column);
 751                                insertions.push((
 752                                    buffer.anchor_before(range.start)
 753                                        ..buffer.anchor_before(range.end),
 754                                    new_text.clone(),
 755                                ));
 756                            } else if !range.is_empty() {
 757                                deletions.push((
 758                                    buffer.anchor_before(range.start)
 759                                        ..buffer.anchor_before(range.end),
 760                                    empty_str.clone(),
 761                                ));
 762                            }
 763                        }
 764
 765                        let deletion_autoindent_mode =
 766                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 767                                Some(AutoindentMode::Block {
 768                                    original_indent_columns: Default::default(),
 769                                })
 770                            } else {
 771                                autoindent_mode.clone()
 772                            };
 773                        let insertion_autoindent_mode =
 774                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 775                                Some(AutoindentMode::Block {
 776                                    original_indent_columns,
 777                                })
 778                            } else {
 779                                autoindent_mode.clone()
 780                            };
 781
 782                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 783                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 784                    })
 785            }
 786
 787            cx.emit(Event::ExcerptsEdited {
 788                ids: edited_excerpt_ids,
 789            });
 790        }
 791    }
 792
 793    fn convert_edits_to_buffer_edits(
 794        &self,
 795        edits: Vec<(Range<usize>, Arc<str>)>,
 796        snapshot: &MultiBufferSnapshot,
 797        original_indent_columns: &[u32],
 798    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 799        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 800        let mut edited_excerpt_ids = Vec::new();
 801        let mut cursor = snapshot.cursor::<usize>();
 802        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 803            let original_indent_column = original_indent_columns.get(ix).copied().unwrap_or(0);
 804
 805            cursor.seek(&range.start);
 806            let mut start_region = cursor.region().expect("start offset out of bounds");
 807            if !start_region.is_main_buffer {
 808                cursor.next();
 809                if let Some(region) = cursor.region() {
 810                    start_region = region;
 811                } else {
 812                    continue;
 813                }
 814            }
 815
 816            if range.end < start_region.range.start {
 817                continue;
 818            }
 819
 820            if range.end > start_region.range.end {
 821                cursor.seek_forward(&range.end);
 822            }
 823            let mut end_region = cursor.region().expect("end offset out of bounds");
 824            if !end_region.is_main_buffer {
 825                cursor.prev();
 826                if let Some(region) = cursor.region() {
 827                    end_region = region;
 828                } else {
 829                    continue;
 830                }
 831            }
 832
 833            if range.start > end_region.range.end {
 834                continue;
 835            }
 836
 837            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 838            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 839            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 840                .min(start_region.buffer_range.end);
 841            let buffer_end =
 842                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 843
 844            if start_region.excerpt.id == end_region.excerpt.id {
 845                if start_region.is_main_buffer {
 846                    edited_excerpt_ids.push(start_region.excerpt.id);
 847                    buffer_edits
 848                        .entry(start_region.buffer.remote_id())
 849                        .or_default()
 850                        .push(BufferEdit {
 851                            range: buffer_start..buffer_end,
 852                            new_text,
 853                            is_insertion: true,
 854                            original_indent_column,
 855                            excerpt_id: start_region.excerpt.id,
 856                        });
 857                }
 858            } else {
 859                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 860                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 861                if start_region.is_main_buffer {
 862                    edited_excerpt_ids.push(start_region.excerpt.id);
 863                    buffer_edits
 864                        .entry(start_region.buffer.remote_id())
 865                        .or_default()
 866                        .push(BufferEdit {
 867                            range: start_excerpt_range,
 868                            new_text: new_text.clone(),
 869                            is_insertion: true,
 870                            original_indent_column,
 871                            excerpt_id: start_region.excerpt.id,
 872                        });
 873                }
 874                if end_region.is_main_buffer {
 875                    edited_excerpt_ids.push(end_region.excerpt.id);
 876                    buffer_edits
 877                        .entry(end_region.buffer.remote_id())
 878                        .or_default()
 879                        .push(BufferEdit {
 880                            range: end_excerpt_range,
 881                            new_text: new_text.clone(),
 882                            is_insertion: false,
 883                            original_indent_column,
 884                            excerpt_id: end_region.excerpt.id,
 885                        });
 886                }
 887
 888                cursor.seek(&range.start);
 889                cursor.next_excerpt();
 890                while let Some(region) = cursor.region() {
 891                    if region.excerpt.id == end_region.excerpt.id {
 892                        break;
 893                    }
 894                    if region.is_main_buffer {
 895                        edited_excerpt_ids.push(region.excerpt.id);
 896                        buffer_edits
 897                            .entry(region.buffer.remote_id())
 898                            .or_default()
 899                            .push(BufferEdit {
 900                                range: region.buffer_range,
 901                                new_text: new_text.clone(),
 902                                is_insertion: false,
 903                                original_indent_column,
 904                                excerpt_id: region.excerpt.id,
 905                            });
 906                    }
 907                    cursor.next_excerpt();
 908                }
 909            }
 910        }
 911        (buffer_edits, edited_excerpt_ids)
 912    }
 913
 914    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 915    where
 916        I: IntoIterator<Item = Range<S>>,
 917        S: ToOffset,
 918    {
 919        let snapshot = self.read(cx);
 920        let empty = Arc::<str>::from("");
 921        let edits = ranges
 922            .into_iter()
 923            .map(|range| {
 924                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 925                if range.start > range.end {
 926                    mem::swap(&mut range.start, &mut range.end);
 927                }
 928                (range, empty.clone())
 929            })
 930            .collect::<Vec<_>>();
 931
 932        return autoindent_ranges_internal(self, snapshot, edits, cx);
 933
 934        fn autoindent_ranges_internal(
 935            this: &MultiBuffer,
 936            snapshot: Ref<MultiBufferSnapshot>,
 937            edits: Vec<(Range<usize>, Arc<str>)>,
 938            cx: &mut Context<MultiBuffer>,
 939        ) {
 940            if this.read_only() || this.buffers.borrow().is_empty() {
 941                return;
 942            }
 943
 944            let (buffer_edits, edited_excerpt_ids) =
 945                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
 946            drop(snapshot);
 947
 948            for (buffer_id, mut edits) in buffer_edits {
 949                edits.sort_unstable_by_key(|edit| edit.range.start);
 950
 951                let mut ranges: Vec<Range<usize>> = Vec::new();
 952                for edit in edits {
 953                    if let Some(last_range) = ranges.last_mut() {
 954                        if edit.range.start <= last_range.end {
 955                            last_range.end = last_range.end.max(edit.range.end);
 956                            continue;
 957                        }
 958                    }
 959                    ranges.push(edit.range);
 960                }
 961
 962                this.buffers.borrow()[&buffer_id]
 963                    .buffer
 964                    .update(cx, |buffer, cx| {
 965                        buffer.autoindent_ranges(ranges, cx);
 966                    })
 967            }
 968
 969            cx.emit(Event::ExcerptsEdited {
 970                ids: edited_excerpt_ids,
 971            });
 972        }
 973    }
 974
 975    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
 976    // You can also request the insertion of empty lines above and below the line starting at the returned point.
 977    // Panics if the given position is invalid.
 978    pub fn insert_empty_line(
 979        &mut self,
 980        position: impl ToPoint,
 981        space_above: bool,
 982        space_below: bool,
 983        cx: &mut Context<Self>,
 984    ) -> Point {
 985        let multibuffer_point = position.to_point(&self.read(cx));
 986        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
 987        self.start_transaction(cx);
 988        let empty_line_start = buffer.update(cx, |buffer, cx| {
 989            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
 990        });
 991        self.end_transaction(cx);
 992        multibuffer_point + (empty_line_start - buffer_point)
 993    }
 994
 995    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
 996        self.start_transaction_at(Instant::now(), cx)
 997    }
 998
 999    pub fn start_transaction_at(
1000        &mut self,
1001        now: Instant,
1002        cx: &mut Context<Self>,
1003    ) -> Option<TransactionId> {
1004        if let Some(buffer) = self.as_singleton() {
1005            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1006        }
1007
1008        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1009            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1010        }
1011        self.history.start_transaction(now)
1012    }
1013
1014    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1015        self.end_transaction_at(Instant::now(), cx)
1016    }
1017
1018    pub fn end_transaction_at(
1019        &mut self,
1020        now: Instant,
1021        cx: &mut Context<Self>,
1022    ) -> Option<TransactionId> {
1023        if let Some(buffer) = self.as_singleton() {
1024            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1025        }
1026
1027        let mut buffer_transactions = HashMap::default();
1028        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1029            if let Some(transaction_id) =
1030                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1031            {
1032                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1033            }
1034        }
1035
1036        if self.history.end_transaction(now, buffer_transactions) {
1037            let transaction_id = self.history.group().unwrap();
1038            Some(transaction_id)
1039        } else {
1040            None
1041        }
1042    }
1043
1044    pub fn edited_ranges_for_transaction<D>(
1045        &self,
1046        transaction_id: TransactionId,
1047        cx: &App,
1048    ) -> Vec<Range<D>>
1049    where
1050        D: TextDimension + Ord + Sub<D, Output = D>,
1051    {
1052        let Some(transaction) = self.history.transaction(transaction_id) else {
1053            return Vec::new();
1054        };
1055
1056        let mut ranges = Vec::new();
1057        let snapshot = self.read(cx);
1058        let buffers = self.buffers.borrow();
1059        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1060
1061        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1062            let Some(buffer_state) = buffers.get(buffer_id) else {
1063                continue;
1064            };
1065
1066            let buffer = buffer_state.buffer.read(cx);
1067            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1068                for excerpt_id in &buffer_state.excerpts {
1069                    cursor.seek(excerpt_id, Bias::Left, &());
1070                    if let Some(excerpt) = cursor.item() {
1071                        if excerpt.locator == *excerpt_id {
1072                            let excerpt_buffer_start =
1073                                excerpt.range.context.start.summary::<D>(buffer);
1074                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1075                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1076                            if excerpt_range.contains(&range.start)
1077                                && excerpt_range.contains(&range.end)
1078                            {
1079                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1080
1081                                let mut start = excerpt_start;
1082                                start.add_assign(&(range.start - excerpt_buffer_start));
1083                                let mut end = excerpt_start;
1084                                end.add_assign(&(range.end - excerpt_buffer_start));
1085
1086                                ranges.push(start..end);
1087                                break;
1088                            }
1089                        }
1090                    }
1091                }
1092            }
1093        }
1094
1095        ranges.sort_by_key(|range| range.start);
1096        ranges
1097    }
1098
1099    pub fn merge_transactions(
1100        &mut self,
1101        transaction: TransactionId,
1102        destination: TransactionId,
1103        cx: &mut Context<Self>,
1104    ) {
1105        if let Some(buffer) = self.as_singleton() {
1106            buffer.update(cx, |buffer, _| {
1107                buffer.merge_transactions(transaction, destination)
1108            });
1109        } else if let Some(transaction) = self.history.forget(transaction) {
1110            if let Some(destination) = self.history.transaction_mut(destination) {
1111                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1112                    if let Some(destination_buffer_transaction_id) =
1113                        destination.buffer_transactions.get(&buffer_id)
1114                    {
1115                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1116                            state.buffer.update(cx, |buffer, _| {
1117                                buffer.merge_transactions(
1118                                    buffer_transaction_id,
1119                                    *destination_buffer_transaction_id,
1120                                )
1121                            });
1122                        }
1123                    } else {
1124                        destination
1125                            .buffer_transactions
1126                            .insert(buffer_id, buffer_transaction_id);
1127                    }
1128                }
1129            }
1130        }
1131    }
1132
1133    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1134        self.history.finalize_last_transaction();
1135        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1136            buffer.update(cx, |buffer, _| {
1137                buffer.finalize_last_transaction();
1138            });
1139        }
1140    }
1141
1142    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1143    where
1144        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1145    {
1146        self.history
1147            .push_transaction(buffer_transactions, Instant::now(), cx);
1148        self.history.finalize_last_transaction();
1149    }
1150
1151    pub fn group_until_transaction(
1152        &mut self,
1153        transaction_id: TransactionId,
1154        cx: &mut Context<Self>,
1155    ) {
1156        if let Some(buffer) = self.as_singleton() {
1157            buffer.update(cx, |buffer, _| {
1158                buffer.group_until_transaction(transaction_id)
1159            });
1160        } else {
1161            self.history.group_until(transaction_id);
1162        }
1163    }
1164
1165    pub fn set_active_selections(
1166        &self,
1167        selections: &[Selection<Anchor>],
1168        line_mode: bool,
1169        cursor_shape: CursorShape,
1170        cx: &mut Context<Self>,
1171    ) {
1172        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1173            Default::default();
1174        let snapshot = self.read(cx);
1175        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1176        for selection in selections {
1177            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1178            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1179
1180            cursor.seek(&Some(start_locator), Bias::Left, &());
1181            while let Some(excerpt) = cursor.item() {
1182                if excerpt.locator > *end_locator {
1183                    break;
1184                }
1185
1186                let mut start = excerpt.range.context.start;
1187                let mut end = excerpt.range.context.end;
1188                if excerpt.id == selection.start.excerpt_id {
1189                    start = selection.start.text_anchor;
1190                }
1191                if excerpt.id == selection.end.excerpt_id {
1192                    end = selection.end.text_anchor;
1193                }
1194                selections_by_buffer
1195                    .entry(excerpt.buffer_id)
1196                    .or_default()
1197                    .push(Selection {
1198                        id: selection.id,
1199                        start,
1200                        end,
1201                        reversed: selection.reversed,
1202                        goal: selection.goal,
1203                    });
1204
1205                cursor.next(&());
1206            }
1207        }
1208
1209        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1210            if !selections_by_buffer.contains_key(buffer_id) {
1211                buffer_state
1212                    .buffer
1213                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1214            }
1215        }
1216
1217        for (buffer_id, mut selections) in selections_by_buffer {
1218            self.buffers.borrow()[&buffer_id]
1219                .buffer
1220                .update(cx, |buffer, cx| {
1221                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1222                    let mut selections = selections.into_iter().peekable();
1223                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1224                        let mut selection = selections.next()?;
1225                        while let Some(next_selection) = selections.peek() {
1226                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1227                                let next_selection = selections.next().unwrap();
1228                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1229                                    selection.end = next_selection.end;
1230                                }
1231                            } else {
1232                                break;
1233                            }
1234                        }
1235                        Some(selection)
1236                    }));
1237                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1238                });
1239        }
1240    }
1241
1242    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1243        for buffer in self.buffers.borrow().values() {
1244            buffer
1245                .buffer
1246                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1247        }
1248    }
1249
1250    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1251        let mut transaction_id = None;
1252        if let Some(buffer) = self.as_singleton() {
1253            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1254        } else {
1255            while let Some(transaction) = self.history.pop_undo() {
1256                let mut undone = false;
1257                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1258                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1259                        undone |= buffer.update(cx, |buffer, cx| {
1260                            let undo_to = *buffer_transaction_id;
1261                            if let Some(entry) = buffer.peek_undo_stack() {
1262                                *buffer_transaction_id = entry.transaction_id();
1263                            }
1264                            buffer.undo_to_transaction(undo_to, cx)
1265                        });
1266                    }
1267                }
1268
1269                if undone {
1270                    transaction_id = Some(transaction.id);
1271                    break;
1272                }
1273            }
1274        }
1275
1276        if let Some(transaction_id) = transaction_id {
1277            cx.emit(Event::TransactionUndone { transaction_id });
1278        }
1279
1280        transaction_id
1281    }
1282
1283    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1284        if let Some(buffer) = self.as_singleton() {
1285            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1286        }
1287
1288        while let Some(transaction) = self.history.pop_redo() {
1289            let mut redone = false;
1290            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1291                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1292                    redone |= buffer.update(cx, |buffer, cx| {
1293                        let redo_to = *buffer_transaction_id;
1294                        if let Some(entry) = buffer.peek_redo_stack() {
1295                            *buffer_transaction_id = entry.transaction_id();
1296                        }
1297                        buffer.redo_to_transaction(redo_to, cx)
1298                    });
1299                }
1300            }
1301
1302            if redone {
1303                return Some(transaction.id);
1304            }
1305        }
1306
1307        None
1308    }
1309
1310    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1311        if let Some(buffer) = self.as_singleton() {
1312            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1313        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1314            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1315                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1316                    buffer.update(cx, |buffer, cx| {
1317                        buffer.undo_transaction(*transaction_id, cx)
1318                    });
1319                }
1320            }
1321        }
1322    }
1323
1324    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1325        if let Some(buffer) = self.as_singleton() {
1326            buffer.update(cx, |buffer, _| {
1327                buffer.forget_transaction(transaction_id);
1328            });
1329        } else if let Some(transaction) = self.history.forget(transaction_id) {
1330            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1331                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1332                    state.buffer.update(cx, |buffer, _| {
1333                        buffer.forget_transaction(buffer_transaction_id);
1334                    });
1335                }
1336            }
1337        }
1338    }
1339
1340    pub fn push_excerpts<O>(
1341        &mut self,
1342        buffer: Entity<Buffer>,
1343        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1344        cx: &mut Context<Self>,
1345    ) -> Vec<ExcerptId>
1346    where
1347        O: text::ToOffset,
1348    {
1349        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1350    }
1351
1352    pub fn push_excerpts_with_context_lines<O>(
1353        &mut self,
1354        buffer: Entity<Buffer>,
1355        ranges: Vec<Range<O>>,
1356        context_line_count: u32,
1357        cx: &mut Context<Self>,
1358    ) -> Vec<Range<Anchor>>
1359    where
1360        O: text::ToPoint + text::ToOffset,
1361    {
1362        let buffer_id = buffer.read(cx).remote_id();
1363        let buffer_snapshot = buffer.read(cx).snapshot();
1364        let (excerpt_ranges, range_counts) =
1365            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1366
1367        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1368
1369        let mut anchor_ranges = Vec::new();
1370        let mut ranges = ranges.into_iter();
1371        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1372            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1373                let start = Anchor {
1374                    buffer_id: Some(buffer_id),
1375                    excerpt_id,
1376                    text_anchor: buffer_snapshot.anchor_after(range.start),
1377                    diff_base_anchor: None,
1378                };
1379                let end = Anchor {
1380                    buffer_id: Some(buffer_id),
1381                    excerpt_id,
1382                    text_anchor: buffer_snapshot.anchor_after(range.end),
1383                    diff_base_anchor: None,
1384                };
1385                start..end
1386            }))
1387        }
1388        anchor_ranges
1389    }
1390
1391    pub fn push_multiple_excerpts_with_context_lines(
1392        &self,
1393        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1394        context_line_count: u32,
1395        cx: &mut Context<Self>,
1396    ) -> Task<Vec<Range<Anchor>>> {
1397        use futures::StreamExt;
1398
1399        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1400
1401        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1402
1403        for (buffer, ranges) in buffers_with_ranges {
1404            let (buffer_id, buffer_snapshot) =
1405                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1406
1407            buffer_ids.push(buffer_id);
1408
1409            cx.background_executor()
1410                .spawn({
1411                    let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1412
1413                    async move {
1414                        let (excerpt_ranges, counts) =
1415                            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1416                        excerpt_ranges_tx
1417                            .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1418                            .await
1419                            .ok();
1420                    }
1421                })
1422                .detach()
1423        }
1424
1425        cx.spawn(move |this, mut cx| async move {
1426            let mut results_by_buffer_id = HashMap::default();
1427            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1428                excerpt_ranges_rx.next().await
1429            {
1430                results_by_buffer_id
1431                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1432            }
1433
1434            let mut multi_buffer_ranges = Vec::default();
1435            'outer: for buffer_id in buffer_ids {
1436                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1437                    results_by_buffer_id.remove(&buffer_id)
1438                else {
1439                    continue;
1440                };
1441
1442                let mut ranges = ranges.into_iter();
1443                let mut range_counts = range_counts.into_iter();
1444                for excerpt_ranges in excerpt_ranges.chunks(100) {
1445                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1446                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1447                    }) {
1448                        Ok(excerpt_ids) => excerpt_ids,
1449                        Err(_) => continue 'outer,
1450                    };
1451
1452                    for (excerpt_id, range_count) in
1453                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1454                    {
1455                        for range in ranges.by_ref().take(range_count) {
1456                            let start = Anchor {
1457                                buffer_id: Some(buffer_id),
1458                                excerpt_id,
1459                                text_anchor: range.start,
1460                                diff_base_anchor: None,
1461                            };
1462                            let end = Anchor {
1463                                buffer_id: Some(buffer_id),
1464                                excerpt_id,
1465                                text_anchor: range.end,
1466                                diff_base_anchor: None,
1467                            };
1468                            multi_buffer_ranges.push(start..end);
1469                        }
1470                    }
1471                }
1472            }
1473
1474            multi_buffer_ranges
1475        })
1476    }
1477
1478    pub fn insert_excerpts_after<O>(
1479        &mut self,
1480        prev_excerpt_id: ExcerptId,
1481        buffer: Entity<Buffer>,
1482        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1483        cx: &mut Context<Self>,
1484    ) -> Vec<ExcerptId>
1485    where
1486        O: text::ToOffset,
1487    {
1488        let mut ids = Vec::new();
1489        let mut next_excerpt_id =
1490            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1491                last_entry.id.0 + 1
1492            } else {
1493                1
1494            };
1495        self.insert_excerpts_with_ids_after(
1496            prev_excerpt_id,
1497            buffer,
1498            ranges.into_iter().map(|range| {
1499                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1500                ids.push(id);
1501                (id, range)
1502            }),
1503            cx,
1504        );
1505        ids
1506    }
1507
1508    pub fn insert_excerpts_with_ids_after<O>(
1509        &mut self,
1510        prev_excerpt_id: ExcerptId,
1511        buffer: Entity<Buffer>,
1512        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1513        cx: &mut Context<Self>,
1514    ) where
1515        O: text::ToOffset,
1516    {
1517        assert_eq!(self.history.transaction_depth, 0);
1518        let mut ranges = ranges.into_iter().peekable();
1519        if ranges.peek().is_none() {
1520            return Default::default();
1521        }
1522
1523        self.sync(cx);
1524
1525        let buffer_id = buffer.read(cx).remote_id();
1526        let buffer_snapshot = buffer.read(cx).snapshot();
1527
1528        let mut buffers = self.buffers.borrow_mut();
1529        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1530            last_version: buffer_snapshot.version().clone(),
1531            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1532            excerpts: Default::default(),
1533            _subscriptions: [
1534                cx.observe(&buffer, |_, _, cx| cx.notify()),
1535                cx.subscribe(&buffer, Self::on_buffer_event),
1536            ],
1537            buffer: buffer.clone(),
1538        });
1539
1540        let mut snapshot = self.snapshot.borrow_mut();
1541
1542        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1543        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1544        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1545        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1546        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1547
1548        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1549        new_excerpts.update_last(
1550            |excerpt| {
1551                excerpt.has_trailing_newline = true;
1552            },
1553            &(),
1554        );
1555
1556        let next_locator = if let Some(excerpt) = cursor.item() {
1557            excerpt.locator.clone()
1558        } else {
1559            Locator::max()
1560        };
1561
1562        let mut excerpts = Vec::new();
1563        while let Some((id, range)) = ranges.next() {
1564            let locator = Locator::between(&prev_locator, &next_locator);
1565            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1566                buffer_state.excerpts.insert(ix, locator.clone());
1567            }
1568            let range = ExcerptRange {
1569                context: buffer_snapshot.anchor_before(&range.context.start)
1570                    ..buffer_snapshot.anchor_after(&range.context.end),
1571                primary: range.primary.map(|primary| {
1572                    buffer_snapshot.anchor_before(&primary.start)
1573                        ..buffer_snapshot.anchor_after(&primary.end)
1574                }),
1575            };
1576            excerpts.push((id, range.clone()));
1577            let excerpt = Excerpt::new(
1578                id,
1579                locator.clone(),
1580                buffer_id,
1581                buffer_snapshot.clone(),
1582                range,
1583                ranges.peek().is_some() || cursor.item().is_some(),
1584            );
1585            new_excerpts.push(excerpt, &());
1586            prev_locator = locator.clone();
1587
1588            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1589                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1590            }
1591            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1592        }
1593
1594        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1595
1596        let suffix = cursor.suffix(&());
1597        let changed_trailing_excerpt = suffix.is_empty();
1598        new_excerpts.append(suffix, &());
1599        drop(cursor);
1600        snapshot.excerpts = new_excerpts;
1601        snapshot.excerpt_ids = new_excerpt_ids;
1602        if changed_trailing_excerpt {
1603            snapshot.trailing_excerpt_update_count += 1;
1604        }
1605
1606        self.sync_diff_transforms(
1607            snapshot,
1608            vec![Edit {
1609                old: edit_start..edit_start,
1610                new: edit_start..edit_end,
1611            }],
1612            DiffChangeKind::BufferEdited,
1613        );
1614        cx.emit(Event::Edited {
1615            singleton_buffer_edited: false,
1616            edited_buffer: None,
1617        });
1618        cx.emit(Event::ExcerptsAdded {
1619            buffer,
1620            predecessor: prev_excerpt_id,
1621            excerpts,
1622        });
1623        cx.notify();
1624    }
1625
1626    pub fn clear(&mut self, cx: &mut Context<Self>) {
1627        self.sync(cx);
1628        let ids = self.excerpt_ids();
1629        self.buffers.borrow_mut().clear();
1630        let mut snapshot = self.snapshot.borrow_mut();
1631        let start = ExcerptOffset::new(0);
1632        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1633        snapshot.excerpts = Default::default();
1634        snapshot.trailing_excerpt_update_count += 1;
1635        snapshot.is_dirty = false;
1636        snapshot.has_deleted_file = false;
1637        snapshot.has_conflict = false;
1638
1639        self.sync_diff_transforms(
1640            snapshot,
1641            vec![Edit {
1642                old: start..prev_len,
1643                new: start..start,
1644            }],
1645            DiffChangeKind::BufferEdited,
1646        );
1647        cx.emit(Event::Edited {
1648            singleton_buffer_edited: false,
1649            edited_buffer: None,
1650        });
1651        cx.emit(Event::ExcerptsRemoved { ids });
1652        cx.notify();
1653    }
1654
1655    pub fn excerpts_for_buffer(
1656        &self,
1657        buffer: &Entity<Buffer>,
1658        cx: &App,
1659    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1660        let mut excerpts = Vec::new();
1661        let snapshot = self.read(cx);
1662        let buffers = self.buffers.borrow();
1663        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1664        for locator in buffers
1665            .get(&buffer.read(cx).remote_id())
1666            .map(|state| &state.excerpts)
1667            .into_iter()
1668            .flatten()
1669        {
1670            cursor.seek_forward(&Some(locator), Bias::Left, &());
1671            if let Some(excerpt) = cursor.item() {
1672                if excerpt.locator == *locator {
1673                    excerpts.push((excerpt.id, excerpt.range.clone()));
1674                }
1675            }
1676        }
1677
1678        excerpts
1679    }
1680
1681    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1682        let snapshot = self.read(cx);
1683        let buffers = self.buffers.borrow();
1684        let mut excerpts = snapshot
1685            .excerpts
1686            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1687        let mut diff_transforms = snapshot
1688            .diff_transforms
1689            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1690        diff_transforms.next(&());
1691        let locators = buffers
1692            .get(&buffer_id)
1693            .into_iter()
1694            .flat_map(|state| &state.excerpts);
1695        let mut result = Vec::new();
1696        for locator in locators {
1697            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1698            if let Some(excerpt) = excerpts.item() {
1699                if excerpt.locator == *locator {
1700                    let excerpt_start = excerpts.start().1.clone();
1701                    let excerpt_end =
1702                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1703
1704                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1705                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1706                    let start = diff_transforms.start().1 .0 + overshoot;
1707
1708                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1709                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1710                    let end = diff_transforms.start().1 .0 + overshoot;
1711
1712                    result.push(start..end)
1713                }
1714            }
1715        }
1716        result
1717    }
1718
1719    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1720        self.snapshot
1721            .borrow()
1722            .excerpts
1723            .iter()
1724            .map(|entry| entry.buffer_id)
1725            .collect()
1726    }
1727
1728    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1729        self.snapshot
1730            .borrow()
1731            .excerpts
1732            .iter()
1733            .map(|entry| entry.id)
1734            .collect()
1735    }
1736
1737    pub fn excerpt_containing(
1738        &self,
1739        position: impl ToOffset,
1740        cx: &App,
1741    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1742        let snapshot = self.read(cx);
1743        let offset = position.to_offset(&snapshot);
1744
1745        let mut cursor = snapshot.cursor::<usize>();
1746        cursor.seek(&offset);
1747        cursor
1748            .excerpt()
1749            .or_else(|| snapshot.excerpts.last())
1750            .map(|excerpt| {
1751                (
1752                    excerpt.id,
1753                    self.buffers
1754                        .borrow()
1755                        .get(&excerpt.buffer_id)
1756                        .unwrap()
1757                        .buffer
1758                        .clone(),
1759                    excerpt.range.context.clone(),
1760                )
1761            })
1762    }
1763
1764    // If point is at the end of the buffer, the last excerpt is returned
1765    pub fn point_to_buffer_offset<T: ToOffset>(
1766        &self,
1767        point: T,
1768        cx: &App,
1769    ) -> Option<(Entity<Buffer>, usize)> {
1770        let snapshot = self.read(cx);
1771        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1772        Some((
1773            self.buffers
1774                .borrow()
1775                .get(&buffer.remote_id())?
1776                .buffer
1777                .clone(),
1778            offset,
1779        ))
1780    }
1781
1782    // If point is at the end of the buffer, the last excerpt is returned
1783    pub fn point_to_buffer_point<T: ToPoint>(
1784        &self,
1785        point: T,
1786        cx: &App,
1787    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1788        let snapshot = self.read(cx);
1789        let point = point.to_point(&snapshot);
1790        let mut cursor = snapshot.cursor::<Point>();
1791        cursor.seek(&point);
1792
1793        cursor.region().and_then(|region| {
1794            if !region.is_main_buffer {
1795                return None;
1796            }
1797
1798            let overshoot = point - region.range.start;
1799            let buffer_point = region.buffer_range.start + overshoot;
1800            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
1801                .buffer
1802                .clone();
1803            Some((buffer, buffer_point, region.excerpt.id))
1804        })
1805    }
1806
1807    pub fn buffer_point_to_anchor(
1808        &self,
1809        buffer: &Entity<Buffer>,
1810        point: Point,
1811        cx: &App,
1812    ) -> Option<Anchor> {
1813        let mut found = None;
1814        let snapshot = buffer.read(cx).snapshot();
1815        for (excerpt_id, range) in self.excerpts_for_buffer(buffer, cx) {
1816            let start = range.context.start.to_point(&snapshot);
1817            let end = range.context.end.to_point(&snapshot);
1818            if start <= point && point < end {
1819                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1820                break;
1821            }
1822            if point < start {
1823                found = Some((start, excerpt_id));
1824            }
1825            if point > end {
1826                found = Some((end, excerpt_id));
1827            }
1828        }
1829
1830        found.map(|(point, excerpt_id)| {
1831            let text_anchor = snapshot.anchor_after(point);
1832            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1833        })
1834    }
1835
1836    pub fn remove_excerpts(
1837        &mut self,
1838        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1839        cx: &mut Context<Self>,
1840    ) {
1841        self.sync(cx);
1842        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1843        if ids.is_empty() {
1844            return;
1845        }
1846
1847        let mut buffers = self.buffers.borrow_mut();
1848        let mut snapshot = self.snapshot.borrow_mut();
1849        let mut new_excerpts = SumTree::default();
1850        let mut cursor = snapshot
1851            .excerpts
1852            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
1853        let mut edits = Vec::new();
1854        let mut excerpt_ids = ids.iter().copied().peekable();
1855
1856        while let Some(excerpt_id) = excerpt_ids.next() {
1857            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1858            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1859            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1860
1861            if let Some(mut excerpt) = cursor.item() {
1862                if excerpt.id != excerpt_id {
1863                    continue;
1864                }
1865                let mut old_start = cursor.start().1;
1866
1867                // Skip over the removed excerpt.
1868                'remove_excerpts: loop {
1869                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
1870                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1871                        if buffer_state.excerpts.is_empty() {
1872                            buffers.remove(&excerpt.buffer_id);
1873                        }
1874                    }
1875                    cursor.next(&());
1876
1877                    // Skip over any subsequent excerpts that are also removed.
1878                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1879                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1880                        if let Some(next_excerpt) = cursor.item() {
1881                            if next_excerpt.locator == *next_locator {
1882                                excerpt_ids.next();
1883                                excerpt = next_excerpt;
1884                                continue 'remove_excerpts;
1885                            }
1886                        }
1887                    }
1888
1889                    break;
1890                }
1891
1892                // When removing the last excerpt, remove the trailing newline from
1893                // the previous excerpt.
1894                if cursor.item().is_none() && old_start.value > 0 {
1895                    old_start.value -= 1;
1896                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
1897                }
1898
1899                // Push an edit for the removal of this run of excerpts.
1900                let old_end = cursor.start().1;
1901                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1902                edits.push(Edit {
1903                    old: old_start..old_end,
1904                    new: new_start..new_start,
1905                });
1906            }
1907        }
1908        let suffix = cursor.suffix(&());
1909        let changed_trailing_excerpt = suffix.is_empty();
1910        new_excerpts.append(suffix, &());
1911        drop(cursor);
1912        snapshot.excerpts = new_excerpts;
1913
1914        if changed_trailing_excerpt {
1915            snapshot.trailing_excerpt_update_count += 1;
1916        }
1917
1918        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
1919        cx.emit(Event::Edited {
1920            singleton_buffer_edited: false,
1921            edited_buffer: None,
1922        });
1923        cx.emit(Event::ExcerptsRemoved { ids });
1924        cx.notify();
1925    }
1926
1927    pub fn wait_for_anchors<'a>(
1928        &self,
1929        anchors: impl 'a + Iterator<Item = Anchor>,
1930        cx: &mut Context<Self>,
1931    ) -> impl 'static + Future<Output = Result<()>> {
1932        let borrow = self.buffers.borrow();
1933        let mut error = None;
1934        let mut futures = Vec::new();
1935        for anchor in anchors {
1936            if let Some(buffer_id) = anchor.buffer_id {
1937                if let Some(buffer) = borrow.get(&buffer_id) {
1938                    buffer.buffer.update(cx, |buffer, _| {
1939                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1940                    });
1941                } else {
1942                    error = Some(anyhow!(
1943                        "buffer {buffer_id} is not part of this multi-buffer"
1944                    ));
1945                    break;
1946                }
1947            }
1948        }
1949        async move {
1950            if let Some(error) = error {
1951                Err(error)?;
1952            }
1953            for future in futures {
1954                future.await?;
1955            }
1956            Ok(())
1957        }
1958    }
1959
1960    pub fn text_anchor_for_position<T: ToOffset>(
1961        &self,
1962        position: T,
1963        cx: &App,
1964    ) -> Option<(Entity<Buffer>, language::Anchor)> {
1965        let snapshot = self.read(cx);
1966        let anchor = snapshot.anchor_before(position);
1967        let buffer = self
1968            .buffers
1969            .borrow()
1970            .get(&anchor.buffer_id?)?
1971            .buffer
1972            .clone();
1973        Some((buffer, anchor.text_anchor))
1974    }
1975
1976    fn on_buffer_event(
1977        &mut self,
1978        buffer: Entity<Buffer>,
1979        event: &language::BufferEvent,
1980        cx: &mut Context<Self>,
1981    ) {
1982        cx.emit(match event {
1983            language::BufferEvent::Edited => Event::Edited {
1984                singleton_buffer_edited: true,
1985                edited_buffer: Some(buffer.clone()),
1986            },
1987            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
1988            language::BufferEvent::Saved => Event::Saved,
1989            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1990            language::BufferEvent::Reloaded => Event::Reloaded,
1991            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
1992            language::BufferEvent::LanguageChanged => {
1993                Event::LanguageChanged(buffer.read(cx).remote_id())
1994            }
1995            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1996            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1997            language::BufferEvent::Closed => Event::Closed,
1998            language::BufferEvent::Discarded => Event::Discarded,
1999            language::BufferEvent::CapabilityChanged => {
2000                self.capability = buffer.read(cx).capability();
2001                Event::CapabilityChanged
2002            }
2003            language::BufferEvent::Operation { .. } => return,
2004        });
2005    }
2006
2007    fn buffer_diff_changed(
2008        &mut self,
2009        change_set: Entity<BufferChangeSet>,
2010        range: Range<text::Anchor>,
2011        cx: &mut Context<Self>,
2012    ) {
2013        let change_set = change_set.read(cx);
2014        let buffer_id = change_set.buffer_id;
2015        let diff = change_set.diff_to_buffer.clone();
2016        let base_text = change_set.base_text.clone();
2017        self.sync(cx);
2018        let mut snapshot = self.snapshot.borrow_mut();
2019        let base_text_changed = snapshot
2020            .diffs
2021            .get(&buffer_id)
2022            .map_or(true, |diff_snapshot| {
2023                change_set.base_text.as_ref().map_or(true, |base_text| {
2024                    base_text.remote_id() != diff_snapshot.base_text.remote_id()
2025                })
2026            });
2027
2028        if let Some(base_text) = base_text {
2029            snapshot.diffs.insert(
2030                buffer_id,
2031                DiffSnapshot {
2032                    diff: diff.clone(),
2033                    base_text,
2034                },
2035            );
2036        } else {
2037            snapshot.diffs.remove(&buffer_id);
2038        }
2039        let buffers = self.buffers.borrow();
2040        let Some(buffer_state) = buffers.get(&buffer_id) else {
2041            return;
2042        };
2043
2044        let diff_change_range = range.to_offset(buffer_state.buffer.read(cx));
2045
2046        let mut excerpt_edits = Vec::new();
2047        for locator in &buffer_state.excerpts {
2048            let mut cursor = snapshot
2049                .excerpts
2050                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2051            cursor.seek_forward(&Some(locator), Bias::Left, &());
2052            if let Some(excerpt) = cursor.item() {
2053                if excerpt.locator == *locator {
2054                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2055                    if diff_change_range.end < excerpt_buffer_range.start
2056                        || diff_change_range.start > excerpt_buffer_range.end
2057                    {
2058                        continue;
2059                    }
2060                    let excerpt_start = cursor.start().1;
2061                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2062                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2063                        diff_change_range
2064                            .start
2065                            .saturating_sub(excerpt_buffer_range.start),
2066                    );
2067                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2068                        diff_change_range
2069                            .end
2070                            .saturating_sub(excerpt_buffer_range.start),
2071                    );
2072                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2073                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2074                    excerpt_edits.push(Edit {
2075                        old: edit_start..edit_end,
2076                        new: edit_start..edit_end,
2077                    });
2078                }
2079            }
2080        }
2081
2082        self.sync_diff_transforms(
2083            snapshot,
2084            excerpt_edits,
2085            DiffChangeKind::DiffUpdated {
2086                base_changed: base_text_changed,
2087            },
2088        );
2089        cx.emit(Event::Edited {
2090            singleton_buffer_edited: false,
2091            edited_buffer: None,
2092        });
2093    }
2094
2095    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2096        self.buffers
2097            .borrow()
2098            .values()
2099            .map(|state| state.buffer.clone())
2100            .collect()
2101    }
2102
2103    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2104        self.buffers
2105            .borrow()
2106            .get(&buffer_id)
2107            .map(|state| state.buffer.clone())
2108    }
2109
2110    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2111        self.point_to_buffer_offset(point, cx)
2112            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2113    }
2114
2115    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2116        let mut language = None;
2117        let mut file = None;
2118        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2119            let buffer = buffer.read(cx);
2120            language = buffer.language_at(offset);
2121            file = buffer.file();
2122        }
2123        language_settings(language.map(|l| l.name()), file, cx)
2124    }
2125
2126    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2127        self.buffers
2128            .borrow()
2129            .values()
2130            .for_each(|state| f(&state.buffer))
2131    }
2132
2133    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2134        if let Some(title) = self.title.as_ref() {
2135            return title.into();
2136        }
2137
2138        if let Some(buffer) = self.as_singleton() {
2139            if let Some(file) = buffer.read(cx).file() {
2140                return file.file_name(cx).to_string_lossy();
2141            }
2142        }
2143
2144        "untitled".into()
2145    }
2146
2147    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2148        self.title = Some(title);
2149        cx.notify();
2150    }
2151
2152    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2153    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2154        for buffer_state in self.buffers.borrow().values() {
2155            buffer_state
2156                .buffer
2157                .update(cx, |buffer, _cx| buffer.refresh_preview());
2158        }
2159    }
2160
2161    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2162    pub fn preserve_preview(&self, cx: &App) -> bool {
2163        self.buffers
2164            .borrow()
2165            .values()
2166            .all(|state| state.buffer.read(cx).preserve_preview())
2167    }
2168
2169    #[cfg(any(test, feature = "test-support"))]
2170    pub fn is_parsing(&self, cx: &App) -> bool {
2171        self.as_singleton().unwrap().read(cx).is_parsing()
2172    }
2173
2174    pub fn add_change_set(&mut self, change_set: Entity<BufferChangeSet>, cx: &mut Context<Self>) {
2175        let buffer_id = change_set.read(cx).buffer_id;
2176        self.buffer_diff_changed(change_set.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2177        self.diff_bases.insert(
2178            buffer_id,
2179            ChangeSetState {
2180                _subscription: cx.subscribe(
2181                    &change_set,
2182                    |this, change_set, event, cx| match event {
2183                        BufferChangeSetEvent::DiffChanged { changed_range } => {
2184                            this.buffer_diff_changed(change_set, changed_range.clone(), cx);
2185                        }
2186                    },
2187                ),
2188                change_set,
2189            },
2190        );
2191    }
2192
2193    pub fn change_set_for(&self, buffer_id: BufferId) -> Option<Entity<BufferChangeSet>> {
2194        self.diff_bases
2195            .get(&buffer_id)
2196            .map(|state| state.change_set.clone())
2197    }
2198
2199    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2200        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2201    }
2202
2203    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2204        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2205    }
2206
2207    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2208        self.all_diff_hunks_expanded = true;
2209        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2210    }
2211
2212    pub fn all_diff_hunks_expanded(&mut self) -> bool {
2213        self.all_diff_hunks_expanded
2214    }
2215
2216    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2217        self.read(cx)
2218            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2219            .nth(1)
2220            .is_some()
2221    }
2222
2223    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2224        let snapshot = self.read(cx);
2225        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2226        for range in ranges {
2227            let range = range.to_point(&snapshot);
2228            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2229            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2230            let start = start.saturating_sub(1);
2231            let end = snapshot.len().min(end + 1);
2232            cursor.seek(&start, Bias::Right, &());
2233            while let Some(item) = cursor.item() {
2234                if *cursor.start() >= end {
2235                    break;
2236                }
2237                if item.hunk_anchor().is_some() {
2238                    return true;
2239                }
2240                cursor.next(&());
2241            }
2242        }
2243        false
2244    }
2245
2246    fn expand_or_collapse_diff_hunks(
2247        &mut self,
2248        ranges: Vec<Range<Anchor>>,
2249        expand: bool,
2250        cx: &mut Context<Self>,
2251    ) {
2252        self.sync(cx);
2253        let snapshot = self.snapshot.borrow_mut();
2254        let mut excerpt_edits = Vec::new();
2255        for range in ranges.iter() {
2256            let end_excerpt_id = range.end.excerpt_id;
2257            let range = range.to_point(&snapshot);
2258            let mut peek_end = range.end;
2259            if range.end.row < snapshot.max_row().0 {
2260                peek_end = Point::new(range.end.row + 1, 0);
2261            };
2262
2263            for diff_hunk in snapshot.diff_hunks_in_range(range.start..peek_end) {
2264                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2265                    continue;
2266                }
2267                let start = Anchor::in_buffer(
2268                    diff_hunk.excerpt_id,
2269                    diff_hunk.buffer_id,
2270                    diff_hunk.buffer_range.start,
2271                );
2272                let end = Anchor::in_buffer(
2273                    diff_hunk.excerpt_id,
2274                    diff_hunk.buffer_id,
2275                    diff_hunk.buffer_range.end,
2276                );
2277                let start = snapshot.excerpt_offset_for_anchor(&start);
2278                let end = snapshot.excerpt_offset_for_anchor(&end);
2279                excerpt_edits.push(text::Edit {
2280                    old: start..end,
2281                    new: start..end,
2282                });
2283            }
2284        }
2285
2286        self.sync_diff_transforms(
2287            snapshot,
2288            excerpt_edits,
2289            DiffChangeKind::ExpandOrCollapseHunks { expand },
2290        );
2291        cx.emit(Event::DiffHunksToggled);
2292        cx.emit(Event::Edited {
2293            singleton_buffer_edited: false,
2294            edited_buffer: None,
2295        });
2296    }
2297
2298    pub fn resize_excerpt(
2299        &mut self,
2300        id: ExcerptId,
2301        range: Range<text::Anchor>,
2302        cx: &mut Context<Self>,
2303    ) {
2304        self.sync(cx);
2305
2306        let mut snapshot = self.snapshot.borrow_mut();
2307        let locator = snapshot.excerpt_locator_for_id(id);
2308        let mut new_excerpts = SumTree::default();
2309        let mut cursor = snapshot
2310            .excerpts
2311            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2312        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2313
2314        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2315        new_excerpts.append(prefix, &());
2316
2317        let mut excerpt = cursor.item().unwrap().clone();
2318        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2319
2320        excerpt.range.context.start = range.start;
2321        excerpt.range.context.end = range.end;
2322        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2323
2324        excerpt.text_summary = excerpt
2325            .buffer
2326            .text_summary_for_range(excerpt.range.context.clone());
2327
2328        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2329        let old_start_offset = cursor.start().1;
2330        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2331        let edit = Edit {
2332            old: old_start_offset..old_start_offset + old_text_len,
2333            new: new_start_offset..new_start_offset + new_text_len,
2334        };
2335
2336        if let Some(last_edit) = edits.last_mut() {
2337            if last_edit.old.end == edit.old.start {
2338                last_edit.old.end = edit.old.end;
2339                last_edit.new.end = edit.new.end;
2340            } else {
2341                edits.push(edit);
2342            }
2343        } else {
2344            edits.push(edit);
2345        }
2346
2347        new_excerpts.push(excerpt, &());
2348
2349        cursor.next(&());
2350
2351        new_excerpts.append(cursor.suffix(&()), &());
2352
2353        drop(cursor);
2354        snapshot.excerpts = new_excerpts;
2355
2356        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
2357        cx.emit(Event::Edited {
2358            singleton_buffer_edited: false,
2359            edited_buffer: None,
2360        });
2361        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2362        cx.notify();
2363    }
2364
2365    pub fn expand_excerpts(
2366        &mut self,
2367        ids: impl IntoIterator<Item = ExcerptId>,
2368        line_count: u32,
2369        direction: ExpandExcerptDirection,
2370        cx: &mut Context<Self>,
2371    ) {
2372        if line_count == 0 {
2373            return;
2374        }
2375        self.sync(cx);
2376        let mut snapshot = self.snapshot.borrow_mut();
2377
2378        let ids = ids.into_iter().collect::<Vec<_>>();
2379        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2380        let mut new_excerpts = SumTree::default();
2381        let mut cursor = snapshot
2382            .excerpts
2383            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2384        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2385
2386        for locator in &locators {
2387            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2388            new_excerpts.append(prefix, &());
2389
2390            let mut excerpt = cursor.item().unwrap().clone();
2391            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2392
2393            let up_line_count = if direction.should_expand_up() {
2394                line_count
2395            } else {
2396                0
2397            };
2398
2399            let start_row = excerpt
2400                .range
2401                .context
2402                .start
2403                .to_point(&excerpt.buffer)
2404                .row
2405                .saturating_sub(up_line_count);
2406            let start_point = Point::new(start_row, 0);
2407            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2408
2409            let down_line_count = if direction.should_expand_down() {
2410                line_count
2411            } else {
2412                0
2413            };
2414
2415            let mut end_point = excerpt.buffer.clip_point(
2416                excerpt.range.context.end.to_point(&excerpt.buffer)
2417                    + Point::new(down_line_count, 0),
2418                Bias::Left,
2419            );
2420            end_point.column = excerpt.buffer.line_len(end_point.row);
2421            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2422            excerpt.max_buffer_row = end_point.row;
2423
2424            excerpt.text_summary = excerpt
2425                .buffer
2426                .text_summary_for_range(excerpt.range.context.clone());
2427
2428            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2429            let old_start_offset = cursor.start().1;
2430            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2431            let edit = Edit {
2432                old: old_start_offset..old_start_offset + old_text_len,
2433                new: new_start_offset..new_start_offset + new_text_len,
2434            };
2435
2436            if let Some(last_edit) = edits.last_mut() {
2437                if last_edit.old.end == edit.old.start {
2438                    last_edit.old.end = edit.old.end;
2439                    last_edit.new.end = edit.new.end;
2440                } else {
2441                    edits.push(edit);
2442                }
2443            } else {
2444                edits.push(edit);
2445            }
2446
2447            new_excerpts.push(excerpt, &());
2448
2449            cursor.next(&());
2450        }
2451
2452        new_excerpts.append(cursor.suffix(&()), &());
2453
2454        drop(cursor);
2455        snapshot.excerpts = new_excerpts;
2456
2457        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
2458        cx.emit(Event::Edited {
2459            singleton_buffer_edited: false,
2460            edited_buffer: None,
2461        });
2462        cx.emit(Event::ExcerptsExpanded { ids });
2463        cx.notify();
2464    }
2465
2466    fn sync(&self, cx: &App) {
2467        let mut snapshot = self.snapshot.borrow_mut();
2468        let mut excerpts_to_edit = Vec::new();
2469        let mut non_text_state_updated = false;
2470        let mut is_dirty = false;
2471        let mut has_deleted_file = false;
2472        let mut has_conflict = false;
2473        let mut edited = false;
2474        let mut buffers = self.buffers.borrow_mut();
2475        for buffer_state in buffers.values_mut() {
2476            let buffer = buffer_state.buffer.read(cx);
2477            let version = buffer.version();
2478            let non_text_state_update_count = buffer.non_text_state_update_count();
2479
2480            let buffer_edited = version.changed_since(&buffer_state.last_version);
2481            let buffer_non_text_state_updated =
2482                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2483            if buffer_edited || buffer_non_text_state_updated {
2484                buffer_state.last_version = version;
2485                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2486                excerpts_to_edit.extend(
2487                    buffer_state
2488                        .excerpts
2489                        .iter()
2490                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2491                );
2492            }
2493
2494            edited |= buffer_edited;
2495            non_text_state_updated |= buffer_non_text_state_updated;
2496            is_dirty |= buffer.is_dirty();
2497            has_deleted_file |= buffer
2498                .file()
2499                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2500            has_conflict |= buffer.has_conflict();
2501        }
2502        if edited {
2503            snapshot.edit_count += 1;
2504        }
2505        if non_text_state_updated {
2506            snapshot.non_text_state_update_count += 1;
2507        }
2508        snapshot.is_dirty = is_dirty;
2509        snapshot.has_deleted_file = has_deleted_file;
2510        snapshot.has_conflict = has_conflict;
2511
2512        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2513
2514        let mut edits = Vec::new();
2515        let mut new_excerpts = SumTree::default();
2516        let mut cursor = snapshot
2517            .excerpts
2518            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2519
2520        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2521            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2522            let old_excerpt = cursor.item().unwrap();
2523            let buffer = buffer.read(cx);
2524            let buffer_id = buffer.remote_id();
2525
2526            let mut new_excerpt;
2527            if buffer_edited {
2528                edits.extend(
2529                    buffer
2530                        .edits_since_in_range::<usize>(
2531                            old_excerpt.buffer.version(),
2532                            old_excerpt.range.context.clone(),
2533                        )
2534                        .map(|edit| {
2535                            let excerpt_old_start = cursor.start().1;
2536                            let excerpt_new_start =
2537                                ExcerptOffset::new(new_excerpts.summary().text.len);
2538                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2539                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2540                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2541                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2542                            Edit {
2543                                old: old_start..old_end,
2544                                new: new_start..new_end,
2545                            }
2546                        }),
2547                );
2548
2549                new_excerpt = Excerpt::new(
2550                    old_excerpt.id,
2551                    locator.clone(),
2552                    buffer_id,
2553                    buffer.snapshot(),
2554                    old_excerpt.range.clone(),
2555                    old_excerpt.has_trailing_newline,
2556                );
2557            } else {
2558                new_excerpt = old_excerpt.clone();
2559                new_excerpt.buffer = buffer.snapshot();
2560            }
2561
2562            new_excerpts.push(new_excerpt, &());
2563            cursor.next(&());
2564        }
2565        new_excerpts.append(cursor.suffix(&()), &());
2566
2567        drop(cursor);
2568        snapshot.excerpts = new_excerpts;
2569
2570        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
2571    }
2572
2573    fn sync_diff_transforms(
2574        &self,
2575        mut snapshot: RefMut<MultiBufferSnapshot>,
2576        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2577        change_kind: DiffChangeKind,
2578    ) {
2579        if excerpt_edits.is_empty() {
2580            return;
2581        }
2582
2583        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2584        let mut old_diff_transforms = snapshot
2585            .diff_transforms
2586            .cursor::<(ExcerptOffset, usize)>(&());
2587        let mut new_diff_transforms = SumTree::default();
2588        let mut old_expanded_hunks = HashSet::default();
2589        let mut output_edits = Vec::new();
2590        let mut output_delta = 0_isize;
2591        let mut at_transform_boundary = true;
2592        let mut end_of_current_insert = None;
2593
2594        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2595        while let Some(edit) = excerpt_edits.next() {
2596            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2597            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2598                excerpts.prev(&());
2599            }
2600
2601            // Keep any transforms that are before the edit.
2602            if at_transform_boundary {
2603                at_transform_boundary = false;
2604                let transforms_before_edit =
2605                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2606                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2607                if let Some(transform) = old_diff_transforms.item() {
2608                    if old_diff_transforms.end(&()).0 == edit.old.start
2609                        && old_diff_transforms.start().0 < edit.old.start
2610                    {
2611                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2612                        old_diff_transforms.next(&());
2613                    }
2614                }
2615            }
2616
2617            // Compute the start of the edit in output coordinates.
2618            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2619            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2620            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2621
2622            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2623                &edit,
2624                &mut excerpts,
2625                &mut old_diff_transforms,
2626                &mut new_diff_transforms,
2627                &mut end_of_current_insert,
2628                &mut old_expanded_hunks,
2629                &snapshot,
2630                change_kind,
2631            );
2632
2633            // Compute the end of the edit in output coordinates.
2634            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2635            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2636            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2637            let edit_new_end =
2638                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2639            let output_edit = Edit {
2640                old: edit_old_start..edit_old_end,
2641                new: edit_new_start..edit_new_end,
2642            };
2643
2644            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2645            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2646            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2647                output_edits.push(output_edit);
2648            }
2649
2650            // If this is the last edit that intersects the current diff transform,
2651            // then recreate the content up to the end of this transform, to prepare
2652            // for reusing additional slices of the old transforms.
2653            if excerpt_edits.peek().map_or(true, |next_edit| {
2654                next_edit.old.start >= old_diff_transforms.end(&()).0
2655            }) {
2656                let mut excerpt_offset = edit.new.end;
2657                if old_diff_transforms.start().0 < edit.old.end {
2658                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2659                    old_diff_transforms.next(&());
2660                }
2661                old_expanded_hunks.clear();
2662                self.push_buffer_content_transform(
2663                    &snapshot,
2664                    &mut new_diff_transforms,
2665                    excerpt_offset,
2666                    end_of_current_insert,
2667                );
2668                at_transform_boundary = true;
2669            }
2670        }
2671
2672        // Keep any transforms that are after the last edit.
2673        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2674
2675        // Ensure there's always at least one buffer content transform.
2676        if new_diff_transforms.is_empty() {
2677            new_diff_transforms.push(
2678                DiffTransform::BufferContent {
2679                    summary: Default::default(),
2680                    inserted_hunk_anchor: None,
2681                },
2682                &(),
2683            );
2684        }
2685
2686        self.subscriptions.publish(output_edits);
2687        drop(old_diff_transforms);
2688        drop(excerpts);
2689        snapshot.diff_transforms = new_diff_transforms;
2690        snapshot.edit_count += 1;
2691
2692        #[cfg(any(test, feature = "test-support"))]
2693        snapshot.check_invariants();
2694    }
2695
2696    #[allow(clippy::too_many_arguments)]
2697    fn recompute_diff_transforms_for_edit(
2698        &self,
2699        edit: &Edit<TypedOffset<Excerpt>>,
2700        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2701        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2702        new_diff_transforms: &mut SumTree<DiffTransform>,
2703        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, ExcerptId, text::Anchor)>,
2704        old_expanded_hunks: &mut HashSet<(ExcerptId, text::Anchor)>,
2705        snapshot: &MultiBufferSnapshot,
2706        change_kind: DiffChangeKind,
2707    ) -> bool {
2708        log::trace!(
2709            "recomputing diff transform for edit {:?} => {:?}",
2710            edit.old.start.value..edit.old.end.value,
2711            edit.new.start.value..edit.new.end.value
2712        );
2713
2714        // Record which hunks were previously expanded.
2715        while let Some(item) = old_diff_transforms.item() {
2716            if let Some(hunk_anchor) = item.hunk_anchor() {
2717                log::trace!(
2718                    "previously expanded hunk at {}",
2719                    old_diff_transforms.start().0
2720                );
2721                old_expanded_hunks.insert(hunk_anchor);
2722            }
2723            if old_diff_transforms.end(&()).0 > edit.old.end {
2724                break;
2725            }
2726            old_diff_transforms.next(&());
2727        }
2728
2729        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2730        if old_expanded_hunks.is_empty()
2731            && change_kind == DiffChangeKind::BufferEdited
2732            && !self.all_diff_hunks_expanded
2733        {
2734            return false;
2735        }
2736
2737        // Visit each excerpt that intersects the edit.
2738        let mut did_expand_hunks = false;
2739        while let Some(excerpt) = excerpts.item() {
2740            if excerpt.text_summary.len == 0 {
2741                if excerpts.end(&()) <= edit.new.end {
2742                    excerpts.next(&());
2743                    continue;
2744                } else {
2745                    break;
2746                }
2747            }
2748
2749            // Recompute the expanded hunks in the portion of the excerpt that
2750            // intersects the edit.
2751            if let Some(diff_state) = snapshot.diffs.get(&excerpt.buffer_id) {
2752                let diff = &diff_state.diff;
2753                let base_text = &diff_state.base_text;
2754                let buffer = &excerpt.buffer;
2755                let excerpt_start = *excerpts.start();
2756                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2757                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2758                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2759                let edit_buffer_start =
2760                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2761                let edit_buffer_end =
2762                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2763                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2764                let edit_anchor_range =
2765                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2766
2767                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2768                    let hunk_anchor = (excerpt.id, hunk.buffer_range.start);
2769                    if !hunk_anchor.1.is_valid(buffer) {
2770                        continue;
2771                    }
2772
2773                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2774                    let hunk_excerpt_start = excerpt_start
2775                        + ExcerptOffset::new(
2776                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2777                        );
2778                    let hunk_excerpt_end = excerpt_end.min(
2779                        excerpt_start
2780                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2781                    );
2782
2783                    self.push_buffer_content_transform(
2784                        snapshot,
2785                        new_diff_transforms,
2786                        hunk_excerpt_start,
2787                        *end_of_current_insert,
2788                    );
2789
2790                    // For every existing hunk, determine if it was previously expanded
2791                    // and if it should currently be expanded.
2792                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_anchor);
2793                    let should_expand_hunk = match &change_kind {
2794                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2795                            self.all_diff_hunks_expanded
2796                        }
2797                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2798                            let intersects = hunk_buffer_range.is_empty()
2799                                || hunk_buffer_range.end > edit_buffer_start;
2800                            if *expand {
2801                                intersects
2802                                    || was_previously_expanded
2803                                    || self.all_diff_hunks_expanded
2804                            } else {
2805                                !intersects
2806                                    && (was_previously_expanded || self.all_diff_hunks_expanded)
2807                            }
2808                        }
2809                        _ => was_previously_expanded || self.all_diff_hunks_expanded,
2810                    };
2811
2812                    if should_expand_hunk {
2813                        did_expand_hunks = true;
2814                        log::trace!(
2815                            "expanding hunk {:?}",
2816                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2817                        );
2818
2819                        if !hunk.diff_base_byte_range.is_empty()
2820                            && hunk_buffer_range.start >= edit_buffer_start
2821                            && hunk_buffer_range.start <= excerpt_buffer_end
2822                        {
2823                            let mut text_cursor =
2824                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2825                            let mut base_text_summary =
2826                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2827
2828                            let mut has_trailing_newline = false;
2829                            if base_text_summary.last_line_chars > 0 {
2830                                base_text_summary += TextSummary::newline();
2831                                has_trailing_newline = true;
2832                            }
2833
2834                            new_diff_transforms.push(
2835                                DiffTransform::DeletedHunk {
2836                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2837                                    summary: base_text_summary,
2838                                    buffer_id: excerpt.buffer_id,
2839                                    hunk_anchor,
2840                                    has_trailing_newline,
2841                                },
2842                                &(),
2843                            );
2844                        }
2845
2846                        if !hunk_buffer_range.is_empty() {
2847                            *end_of_current_insert = Some((
2848                                hunk_excerpt_end.min(excerpt_end),
2849                                hunk_anchor.0,
2850                                hunk_anchor.1,
2851                            ));
2852                        }
2853                    }
2854                }
2855            }
2856
2857            if excerpts.end(&()) <= edit.new.end {
2858                excerpts.next(&());
2859            } else {
2860                break;
2861            }
2862        }
2863
2864        did_expand_hunks || !old_expanded_hunks.is_empty()
2865    }
2866
2867    fn append_diff_transforms(
2868        &self,
2869        new_transforms: &mut SumTree<DiffTransform>,
2870        subtree: SumTree<DiffTransform>,
2871    ) {
2872        if let Some(DiffTransform::BufferContent {
2873            inserted_hunk_anchor,
2874            summary,
2875        }) = subtree.first()
2876        {
2877            if self.extend_last_buffer_content_transform(
2878                new_transforms,
2879                *inserted_hunk_anchor,
2880                *summary,
2881            ) {
2882                let mut cursor = subtree.cursor::<()>(&());
2883                cursor.next(&());
2884                cursor.next(&());
2885                new_transforms.append(cursor.suffix(&()), &());
2886                return;
2887            }
2888        }
2889        new_transforms.append(subtree, &());
2890    }
2891
2892    fn push_diff_transform(
2893        &self,
2894        new_transforms: &mut SumTree<DiffTransform>,
2895        transform: DiffTransform,
2896    ) {
2897        if let DiffTransform::BufferContent {
2898            inserted_hunk_anchor,
2899            summary,
2900        } = transform
2901        {
2902            if self.extend_last_buffer_content_transform(
2903                new_transforms,
2904                inserted_hunk_anchor,
2905                summary,
2906            ) {
2907                return;
2908            }
2909        }
2910        new_transforms.push(transform, &());
2911    }
2912
2913    fn push_buffer_content_transform(
2914        &self,
2915        old_snapshot: &MultiBufferSnapshot,
2916        new_transforms: &mut SumTree<DiffTransform>,
2917        end_offset: ExcerptOffset,
2918        current_inserted_hunk: Option<(ExcerptOffset, ExcerptId, text::Anchor)>,
2919    ) {
2920        let inserted_region =
2921            current_inserted_hunk.map(|(insertion_end_offset, excerpt_id, anchor)| {
2922                (
2923                    end_offset.min(insertion_end_offset),
2924                    Some((excerpt_id, anchor)),
2925                )
2926            });
2927        let unchanged_region = [(end_offset, None)];
2928
2929        for (end_offset, inserted_hunk_anchor) in
2930            inserted_region.into_iter().chain(unchanged_region)
2931        {
2932            let start_offset = new_transforms.summary().excerpt_len();
2933            if end_offset <= start_offset {
2934                continue;
2935            }
2936            let summary_to_add = old_snapshot
2937                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2938
2939            if !self.extend_last_buffer_content_transform(
2940                new_transforms,
2941                inserted_hunk_anchor,
2942                summary_to_add,
2943            ) {
2944                new_transforms.push(
2945                    DiffTransform::BufferContent {
2946                        summary: summary_to_add,
2947                        inserted_hunk_anchor,
2948                    },
2949                    &(),
2950                )
2951            }
2952        }
2953    }
2954
2955    fn extend_last_buffer_content_transform(
2956        &self,
2957        new_transforms: &mut SumTree<DiffTransform>,
2958        new_inserted_hunk_anchor: Option<(ExcerptId, text::Anchor)>,
2959        summary_to_add: TextSummary,
2960    ) -> bool {
2961        let mut did_extend = false;
2962        new_transforms.update_last(
2963            |last_transform| {
2964                if let DiffTransform::BufferContent {
2965                    summary,
2966                    inserted_hunk_anchor,
2967                } = last_transform
2968                {
2969                    if *inserted_hunk_anchor == new_inserted_hunk_anchor {
2970                        *summary += summary_to_add;
2971                        did_extend = true;
2972                    }
2973                }
2974            },
2975            &(),
2976        );
2977        did_extend
2978    }
2979}
2980
2981#[cfg(any(test, feature = "test-support"))]
2982impl MultiBuffer {
2983    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2984        let buffer = cx.new(|cx| Buffer::local(text, cx));
2985        cx.new(|cx| Self::singleton(buffer, cx))
2986    }
2987
2988    pub fn build_multi<const COUNT: usize>(
2989        excerpts: [(&str, Vec<Range<Point>>); COUNT],
2990        cx: &mut gpui::App,
2991    ) -> Entity<Self> {
2992        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
2993        for (text, ranges) in excerpts {
2994            let buffer = cx.new(|cx| Buffer::local(text, cx));
2995            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
2996                context: range,
2997                primary: None,
2998            });
2999            multi.update(cx, |multi, cx| {
3000                multi.push_excerpts(buffer, excerpt_ranges, cx)
3001            });
3002        }
3003
3004        multi
3005    }
3006
3007    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3008        cx.new(|cx| Self::singleton(buffer, cx))
3009    }
3010
3011    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3012        cx.new(|cx| {
3013            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3014            let mutation_count = rng.gen_range(1..=5);
3015            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3016            multibuffer
3017        })
3018    }
3019
3020    pub fn randomly_edit(
3021        &mut self,
3022        rng: &mut impl rand::Rng,
3023        edit_count: usize,
3024        cx: &mut Context<Self>,
3025    ) {
3026        use util::RandomCharIter;
3027
3028        let snapshot = self.read(cx);
3029        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3030        let mut last_end = None;
3031        for _ in 0..edit_count {
3032            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3033                break;
3034            }
3035
3036            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3037            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3038            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3039            last_end = Some(end);
3040
3041            let mut range = start..end;
3042            if rng.gen_bool(0.2) {
3043                mem::swap(&mut range.start, &mut range.end);
3044            }
3045
3046            let new_text_len = rng.gen_range(0..10);
3047            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3048
3049            edits.push((range, new_text.into()));
3050        }
3051        log::info!("mutating multi-buffer with {:?}", edits);
3052        drop(snapshot);
3053
3054        self.edit(edits, None, cx);
3055    }
3056
3057    pub fn randomly_edit_excerpts(
3058        &mut self,
3059        rng: &mut impl rand::Rng,
3060        mutation_count: usize,
3061        cx: &mut Context<Self>,
3062    ) {
3063        use rand::prelude::*;
3064        use std::env;
3065        use util::RandomCharIter;
3066
3067        let max_excerpts = env::var("MAX_EXCERPTS")
3068            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3069            .unwrap_or(5);
3070
3071        let mut buffers = Vec::new();
3072        for _ in 0..mutation_count {
3073            if rng.gen_bool(0.05) {
3074                log::info!("Clearing multi-buffer");
3075                self.clear(cx);
3076                continue;
3077            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3078                let ids = self.excerpt_ids();
3079                let mut excerpts = HashSet::default();
3080                for _ in 0..rng.gen_range(0..ids.len()) {
3081                    excerpts.extend(ids.choose(rng).copied());
3082                }
3083
3084                let line_count = rng.gen_range(0..5);
3085
3086                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3087
3088                self.expand_excerpts(
3089                    excerpts.iter().cloned(),
3090                    line_count,
3091                    ExpandExcerptDirection::UpAndDown,
3092                    cx,
3093                );
3094                continue;
3095            }
3096
3097            let excerpt_ids = self.excerpt_ids();
3098            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3099                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3100                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3101                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3102                    let buffer = buffers.last().unwrap().read(cx);
3103                    log::info!(
3104                        "Creating new buffer {} with text: {:?}",
3105                        buffer.remote_id(),
3106                        buffer.text()
3107                    );
3108                    buffers.last().unwrap().clone()
3109                } else {
3110                    self.buffers
3111                        .borrow()
3112                        .values()
3113                        .choose(rng)
3114                        .unwrap()
3115                        .buffer
3116                        .clone()
3117                };
3118
3119                let buffer = buffer_handle.read(cx);
3120                let buffer_text = buffer.text();
3121                let ranges = (0..rng.gen_range(0..5))
3122                    .map(|_| {
3123                        let end_ix =
3124                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3125                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3126                        ExcerptRange {
3127                            context: start_ix..end_ix,
3128                            primary: None,
3129                        }
3130                    })
3131                    .collect::<Vec<_>>();
3132                log::info!(
3133                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3134                    buffer_handle.read(cx).remote_id(),
3135                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3136                    ranges
3137                        .iter()
3138                        .map(|r| &buffer_text[r.context.clone()])
3139                        .collect::<Vec<_>>()
3140                );
3141
3142                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3143                log::info!("Inserted with ids: {:?}", excerpt_id);
3144            } else {
3145                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3146                let mut excerpts_to_remove = excerpt_ids
3147                    .choose_multiple(rng, remove_count)
3148                    .cloned()
3149                    .collect::<Vec<_>>();
3150                let snapshot = self.snapshot.borrow();
3151                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3152                drop(snapshot);
3153                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3154                self.remove_excerpts(excerpts_to_remove, cx);
3155            }
3156        }
3157    }
3158
3159    pub fn randomly_mutate(
3160        &mut self,
3161        rng: &mut impl rand::Rng,
3162        mutation_count: usize,
3163        cx: &mut Context<Self>,
3164    ) {
3165        use rand::prelude::*;
3166
3167        if rng.gen_bool(0.7) || self.singleton {
3168            let buffer = self
3169                .buffers
3170                .borrow()
3171                .values()
3172                .choose(rng)
3173                .map(|state| state.buffer.clone());
3174
3175            if let Some(buffer) = buffer {
3176                buffer.update(cx, |buffer, cx| {
3177                    if rng.gen() {
3178                        buffer.randomly_edit(rng, mutation_count, cx);
3179                    } else {
3180                        buffer.randomly_undo_redo(rng, cx);
3181                    }
3182                });
3183            } else {
3184                self.randomly_edit(rng, mutation_count, cx);
3185            }
3186        } else {
3187            self.randomly_edit_excerpts(rng, mutation_count, cx);
3188        }
3189
3190        self.check_invariants(cx);
3191    }
3192
3193    fn check_invariants(&self, cx: &App) {
3194        self.read(cx).check_invariants();
3195    }
3196}
3197
3198impl EventEmitter<Event> for MultiBuffer {}
3199
3200impl MultiBufferSnapshot {
3201    pub fn text(&self) -> String {
3202        self.chunks(0..self.len(), false)
3203            .map(|chunk| chunk.text)
3204            .collect()
3205    }
3206
3207    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3208        self.reversed_chunks_in_range(0..position.to_offset(self))
3209            .flat_map(|c| c.chars().rev())
3210    }
3211
3212    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3213        let mut cursor = self.cursor::<usize>();
3214        cursor.seek(&range.end);
3215        let current_chunks = cursor.region().as_ref().map(|region| {
3216            let start_overshoot = range.start.saturating_sub(region.range.start);
3217            let end_overshoot = range.end - region.range.start;
3218            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3219            let start = region.buffer_range.start + start_overshoot;
3220            region.buffer.reversed_chunks_in_range(start..end)
3221        });
3222        ReversedMultiBufferChunks {
3223            cursor,
3224            current_chunks,
3225            start: range.start,
3226            offset: range.end,
3227        }
3228    }
3229
3230    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3231        let offset = position.to_offset(self);
3232        self.text_for_range(offset..self.len())
3233            .flat_map(|chunk| chunk.chars())
3234    }
3235
3236    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3237        self.chunks(range, false).map(|chunk| chunk.text)
3238    }
3239
3240    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3241        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3242            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3243    }
3244
3245    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3246    where
3247        T: ToOffset,
3248    {
3249        let position = position.to_offset(self);
3250        position == self.clip_offset(position, Bias::Left)
3251            && self
3252                .bytes_in_range(position..self.len())
3253                .flatten()
3254                .copied()
3255                .take(needle.len())
3256                .eq(needle.bytes())
3257    }
3258
3259    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3260        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3261    }
3262
3263    pub fn diff_hunks_in_range<T: ToOffset>(
3264        &self,
3265        range: Range<T>,
3266    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3267        let range = range.start.to_offset(self)..range.end.to_offset(self);
3268        self.lift_buffer_metadata(range.clone(), move |buffer, buffer_range| {
3269            let diff = self.diffs.get(&buffer.remote_id())?;
3270            let buffer_start = buffer.anchor_before(buffer_range.start);
3271            let buffer_end = buffer.anchor_after(buffer_range.end);
3272            Some(
3273                diff.diff
3274                    .hunks_intersecting_range(buffer_start..buffer_end, buffer)
3275                    .map(|hunk| {
3276                        (
3277                            Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
3278                            hunk,
3279                        )
3280                    }),
3281            )
3282        })
3283        .map(|(range, hunk, excerpt)| {
3284            let end_row = if range.end.column == 0 {
3285                range.end.row
3286            } else {
3287                range.end.row + 1
3288            };
3289            MultiBufferDiffHunk {
3290                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3291                buffer_id: excerpt.buffer_id,
3292                excerpt_id: excerpt.id,
3293                buffer_range: hunk.buffer_range.clone(),
3294                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3295            }
3296        })
3297    }
3298
3299    pub fn excerpt_ids_for_range<T: ToOffset>(
3300        &self,
3301        range: Range<T>,
3302    ) -> impl Iterator<Item = ExcerptId> + '_ {
3303        let range = range.start.to_offset(self)..range.end.to_offset(self);
3304        let mut cursor = self.cursor::<usize>();
3305        cursor.seek(&range.start);
3306        std::iter::from_fn(move || {
3307            let region = cursor.region()?;
3308            if region.range.start >= range.end {
3309                return None;
3310            }
3311            cursor.next_excerpt();
3312            Some(region.excerpt.id)
3313        })
3314    }
3315
3316    pub fn buffer_ids_for_range<T: ToOffset>(
3317        &self,
3318        range: Range<T>,
3319    ) -> impl Iterator<Item = BufferId> + '_ {
3320        let range = range.start.to_offset(self)..range.end.to_offset(self);
3321        let mut cursor = self.cursor::<usize>();
3322        cursor.seek(&range.start);
3323        std::iter::from_fn(move || {
3324            let region = cursor.region()?;
3325            if region.range.start >= range.end {
3326                return None;
3327            }
3328            cursor.next_excerpt();
3329            Some(region.excerpt.buffer_id)
3330        })
3331    }
3332
3333    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3334        &self,
3335        ranges: impl Iterator<Item = Range<T>>,
3336    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3337        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3338    }
3339
3340    pub fn range_to_buffer_ranges<T: ToOffset>(
3341        &self,
3342        range: Range<T>,
3343    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3344        let start = range.start.to_offset(&self);
3345        let end = range.end.to_offset(&self);
3346
3347        let mut cursor = self.cursor::<usize>();
3348        cursor.seek(&start);
3349
3350        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3351        while let Some(region) = cursor.region() {
3352            if region.range.start > end {
3353                break;
3354            }
3355            if region.is_main_buffer {
3356                let start_overshoot = start.saturating_sub(region.range.start);
3357                let end_overshoot = end.saturating_sub(region.range.start);
3358                let start = region
3359                    .buffer_range
3360                    .end
3361                    .min(region.buffer_range.start + start_overshoot);
3362                let end = region
3363                    .buffer_range
3364                    .end
3365                    .min(region.buffer_range.start + end_overshoot);
3366                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3367                    *excerpt_id == region.excerpt.id && prev_range.end == start
3368                }) {
3369                    prev.1.end = end;
3370                } else {
3371                    result.push((region.buffer, start..end, region.excerpt.id));
3372                }
3373            }
3374            cursor.next();
3375        }
3376        result
3377    }
3378
3379    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3380        &self,
3381        range: Range<T>,
3382    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3383        let start = range.start.to_offset(&self);
3384        let end = range.end.to_offset(&self);
3385
3386        let mut cursor = self.cursor::<usize>();
3387        cursor.seek(&start);
3388
3389        std::iter::from_fn(move || {
3390            let region = cursor.region()?;
3391            if region.range.start > end {
3392                return None;
3393            }
3394            let start_overshoot = start.saturating_sub(region.range.start);
3395            let end_overshoot = end.saturating_sub(region.range.start);
3396            let start = region
3397                .buffer_range
3398                .end
3399                .min(region.buffer_range.start + start_overshoot);
3400            let end = region
3401                .buffer_range
3402                .end
3403                .min(region.buffer_range.start + end_overshoot);
3404
3405            let region_excerpt_id = region.excerpt.id;
3406            let deleted_hunk_anchor = if region.is_main_buffer {
3407                None
3408            } else {
3409                Some(self.anchor_before(region.range.start))
3410            };
3411            let result = (
3412                region.buffer,
3413                start..end,
3414                region_excerpt_id,
3415                deleted_hunk_anchor,
3416            );
3417            cursor.next();
3418            Some(result)
3419        })
3420    }
3421
3422    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3423    /// coordinates.
3424    ///
3425    /// The given callback will be called for every excerpt intersecting the given range. It will
3426    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3427    /// The callback should return an iterator of metadata items from that buffer, each paired
3428    /// with a buffer range.
3429    ///
3430    /// The returned iterator yields each of these metadata items, paired with its range in
3431    /// multi-buffer coordinates.
3432    fn lift_buffer_metadata<'a, D, M, I>(
3433        &'a self,
3434        range: Range<usize>,
3435        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<usize>) -> Option<I>,
3436    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3437    where
3438        I: Iterator<Item = (Range<D>, M)> + 'a,
3439        D: TextDimension + Ord + Sub<D, Output = D>,
3440    {
3441        let max_position = D::from_text_summary(&self.text_summary());
3442        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3443        let mut cursor = self.cursor::<DimensionPair<usize, D>>();
3444
3445        // Find the excerpt and buffer offset where the given range ends.
3446        cursor.seek(&DimensionPair {
3447            key: range.end,
3448            value: None,
3449        });
3450        let mut range_end = None;
3451        while let Some(region) = cursor.region() {
3452            if region.is_main_buffer {
3453                let mut buffer_end = region.buffer_range.start.key;
3454                let overshoot = range.end.saturating_sub(region.range.start.key);
3455                buffer_end.add_assign(&overshoot);
3456                range_end = Some((region.excerpt.id, buffer_end));
3457                break;
3458            }
3459            cursor.next();
3460        }
3461
3462        cursor.seek(&DimensionPair {
3463            key: range.start,
3464            value: None,
3465        });
3466
3467        if cursor.region().is_some_and(|region| !region.is_main_buffer) {
3468            cursor.prev();
3469        }
3470
3471        iter::from_fn(move || loop {
3472            let excerpt = cursor.excerpt()?;
3473
3474            // If we have already retrieved metadata for this excerpt, continue to use it.
3475            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3476                .as_mut()
3477                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3478            {
3479                Some(metadata)
3480            }
3481            // Otherwise, compute the intersection of the input range with the excerpt's range,
3482            // and retrieve the metadata for the resulting range.
3483            else {
3484                let region = cursor.region()?;
3485                let buffer_start = if region.is_main_buffer {
3486                    let start_overshoot = range.start.saturating_sub(region.range.start.key);
3487                    region.buffer_range.start.key + start_overshoot
3488                } else {
3489                    cursor.main_buffer_position()?.key
3490                };
3491                let mut buffer_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3492                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3493                    if excerpt.id == end_excerpt_id {
3494                        buffer_end = buffer_end.min(end_buffer_offset);
3495                    }
3496                }
3497
3498                if let Some(iterator) =
3499                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3500                {
3501                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3502                } else {
3503                    None
3504                }
3505            };
3506
3507            // Visit each metadata item.
3508            if let Some((range, metadata)) = metadata_iter.and_then(Iterator::next) {
3509                // Find the multibuffer regions that contain the start and end of
3510                // the metadata item's range.
3511                if range.start > D::default() {
3512                    while let Some(region) = cursor.region() {
3513                        if !region.is_main_buffer
3514                            || region.buffer.remote_id() == excerpt.buffer_id
3515                                && region.buffer_range.end.value.unwrap() < range.start
3516                        {
3517                            cursor.next();
3518                        } else {
3519                            break;
3520                        }
3521                    }
3522                }
3523                let start_region = cursor.region()?;
3524                while let Some(region) = cursor.region() {
3525                    if !region.is_main_buffer
3526                        || region.buffer.remote_id() == excerpt.buffer_id
3527                            && region.buffer_range.end.value.unwrap() <= range.end
3528                    {
3529                        cursor.next();
3530                    } else {
3531                        break;
3532                    }
3533                }
3534                let end_region = cursor
3535                    .region()
3536                    .filter(|region| region.buffer.remote_id() == excerpt.buffer_id);
3537
3538                // Convert the metadata item's range into multibuffer coordinates.
3539                let mut start = start_region.range.start.value.unwrap();
3540                let region_buffer_start = start_region.buffer_range.start.value.unwrap();
3541                if start_region.is_main_buffer && range.start > region_buffer_start {
3542                    start.add_assign(&(range.start - region_buffer_start));
3543                }
3544                let mut end = max_position;
3545                if let Some(end_region) = end_region {
3546                    end = end_region.range.start.value.unwrap();
3547                    debug_assert!(end_region.is_main_buffer);
3548                    let region_buffer_start = end_region.buffer_range.start.value.unwrap();
3549                    if range.end > region_buffer_start {
3550                        end.add_assign(&(range.end - region_buffer_start));
3551                    }
3552                }
3553
3554                return Some((start..end, metadata, excerpt));
3555            }
3556            // When there are no more metadata items for this excerpt, move to the next excerpt.
3557            else {
3558                current_excerpt_metadata.take();
3559                cursor.next_excerpt();
3560            }
3561        })
3562    }
3563
3564    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3565        let offset = position.to_offset(self);
3566
3567        // Go to the region containing the given offset.
3568        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3569        cursor.seek(&DimensionPair {
3570            key: offset,
3571            value: None,
3572        });
3573        let mut region = cursor.region()?;
3574        if region.range.start.key == offset || !region.is_main_buffer {
3575            cursor.prev();
3576            region = cursor.region()?;
3577        }
3578
3579        // Find the corresponding buffer offset.
3580        let overshoot = if region.is_main_buffer {
3581            offset - region.range.start.key
3582        } else {
3583            0
3584        };
3585        let mut max_buffer_offset = region
3586            .buffer
3587            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3588
3589        loop {
3590            let excerpt = cursor.excerpt()?;
3591            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3592            let buffer_offset = excerpt_end.min(max_buffer_offset);
3593            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3594            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3595
3596            if let Some(diff_state) = self.diffs.get(&excerpt.buffer_id) {
3597                for hunk in diff_state.diff.hunks_intersecting_range_rev(
3598                    excerpt.range.context.start..buffer_end,
3599                    &excerpt.buffer,
3600                ) {
3601                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3602                    if hunk.row_range.end >= buffer_end_row {
3603                        continue;
3604                    }
3605
3606                    let hunk_start = Point::new(hunk.row_range.start, 0);
3607                    let hunk_end = Point::new(hunk.row_range.end, 0);
3608
3609                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3610                        key: hunk_range.start,
3611                        value: None,
3612                    });
3613
3614                    let mut region = cursor.region()?;
3615                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3616                    {
3617                        cursor.prev();
3618                        region = cursor.region()?;
3619                    }
3620
3621                    let overshoot = if region.is_main_buffer {
3622                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3623                    } else {
3624                        Point::zero()
3625                    };
3626                    let start = region.range.start.value.unwrap() + overshoot;
3627
3628                    while let Some(region) = cursor.region() {
3629                        if !region.is_main_buffer
3630                            || region.buffer_range.end.value.unwrap() <= hunk_end
3631                        {
3632                            cursor.next();
3633                        } else {
3634                            break;
3635                        }
3636                    }
3637
3638                    let end = if let Some(region) = cursor.region() {
3639                        let overshoot = if region.is_main_buffer {
3640                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3641                        } else {
3642                            Point::zero()
3643                        };
3644                        region.range.start.value.unwrap() + overshoot
3645                    } else {
3646                        self.max_point()
3647                    };
3648
3649                    return Some(MultiBufferDiffHunk {
3650                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3651                        buffer_id: excerpt.buffer_id,
3652                        excerpt_id: excerpt.id,
3653                        buffer_range: hunk.buffer_range.clone(),
3654                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3655                    });
3656                }
3657            }
3658
3659            cursor.prev_excerpt();
3660            max_buffer_offset = usize::MAX;
3661        }
3662    }
3663
3664    pub fn has_diff_hunks(&self) -> bool {
3665        self.diffs.values().any(|diff| !diff.diff.is_empty())
3666    }
3667
3668    pub fn surrounding_word<T: ToOffset>(
3669        &self,
3670        start: T,
3671        for_completion: bool,
3672    ) -> (Range<usize>, Option<CharKind>) {
3673        let mut start = start.to_offset(self);
3674        let mut end = start;
3675        let mut next_chars = self.chars_at(start).peekable();
3676        let mut prev_chars = self.reversed_chars_at(start).peekable();
3677
3678        let classifier = self
3679            .char_classifier_at(start)
3680            .for_completion(for_completion);
3681
3682        let word_kind = cmp::max(
3683            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3684            next_chars.peek().copied().map(|c| classifier.kind(c)),
3685        );
3686
3687        for ch in prev_chars {
3688            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3689                start -= ch.len_utf8();
3690            } else {
3691                break;
3692            }
3693        }
3694
3695        for ch in next_chars {
3696            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3697                end += ch.len_utf8();
3698            } else {
3699                break;
3700            }
3701        }
3702
3703        (start..end, word_kind)
3704    }
3705
3706    pub fn is_singleton(&self) -> bool {
3707        self.singleton
3708    }
3709
3710    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3711        if self.singleton {
3712            self.excerpts
3713                .iter()
3714                .next()
3715                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3716        } else {
3717            None
3718        }
3719    }
3720
3721    pub fn len(&self) -> usize {
3722        self.diff_transforms.summary().output.len
3723    }
3724
3725    pub fn is_empty(&self) -> bool {
3726        self.excerpts.summary().text.len == 0
3727    }
3728
3729    pub fn widest_line_number(&self) -> u32 {
3730        self.excerpts.summary().widest_line_number + 1
3731    }
3732
3733    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3734        let range = range.start.to_offset(self)..range.end.to_offset(self);
3735        let mut excerpts = self.cursor::<usize>();
3736        excerpts.seek(&range.start);
3737
3738        let mut chunk;
3739        let mut has_trailing_newline;
3740        let excerpt_bytes;
3741        if let Some(region) = excerpts.region() {
3742            let mut bytes = region.buffer.bytes_in_range(
3743                region.buffer_range.start + range.start - region.range.start
3744                    ..(region.buffer_range.start + range.end - region.range.start)
3745                        .min(region.buffer_range.end),
3746            );
3747            chunk = bytes.next().unwrap_or(&[][..]);
3748            excerpt_bytes = Some(bytes);
3749            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3750            if chunk.is_empty() && has_trailing_newline {
3751                chunk = b"\n";
3752                has_trailing_newline = false;
3753            }
3754        } else {
3755            chunk = &[][..];
3756            excerpt_bytes = None;
3757            has_trailing_newline = false;
3758        };
3759
3760        MultiBufferBytes {
3761            range,
3762            cursor: excerpts,
3763            excerpt_bytes,
3764            has_trailing_newline,
3765            chunk,
3766        }
3767    }
3768
3769    pub fn reversed_bytes_in_range<T: ToOffset>(
3770        &self,
3771        range: Range<T>,
3772    ) -> ReversedMultiBufferBytes {
3773        let range = range.start.to_offset(self)..range.end.to_offset(self);
3774        let mut chunks = self.reversed_chunks_in_range(range.clone());
3775        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3776        ReversedMultiBufferBytes {
3777            range,
3778            chunks,
3779            chunk,
3780        }
3781    }
3782
3783    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3784        let mut cursor = self.cursor::<Point>();
3785        cursor.seek(&Point::new(start_row.0, 0));
3786        let mut result = MultiBufferRows {
3787            point: Point::new(0, 0),
3788            is_empty: self.excerpts.is_empty(),
3789            cursor,
3790        };
3791        result.seek(start_row);
3792        result
3793    }
3794
3795    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3796        let mut chunks = MultiBufferChunks {
3797            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3798            range: 0..0,
3799            excerpts: self.excerpts.cursor(&()),
3800            diff_transforms: self.diff_transforms.cursor(&()),
3801            diffs: &self.diffs,
3802            diff_base_chunks: None,
3803            excerpt_chunks: None,
3804            buffer_chunk: None,
3805            language_aware,
3806        };
3807        let range = range.start.to_offset(self)..range.end.to_offset(self);
3808        chunks.seek(range);
3809        chunks
3810    }
3811
3812    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3813        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3814    }
3815
3816    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3817        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3818    }
3819
3820    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3821        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3822    }
3823
3824    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3825        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3826            buffer.clip_point_utf16(Unclipped(point), bias)
3827        })
3828    }
3829
3830    pub fn offset_to_point(&self, offset: usize) -> Point {
3831        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3832    }
3833
3834    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3835        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3836    }
3837
3838    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3839        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3840    }
3841
3842    pub fn point_to_offset(&self, point: Point) -> usize {
3843        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3844    }
3845
3846    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3847        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3848    }
3849
3850    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3851        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3852    }
3853
3854    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3855        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3856    }
3857
3858    fn clip_dimension<D>(
3859        &self,
3860        position: D,
3861        bias: Bias,
3862        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3863    ) -> D
3864    where
3865        D: TextDimension + Ord + Sub<D, Output = D>,
3866    {
3867        let mut cursor = self.cursor();
3868        cursor.seek(&position);
3869        if let Some(region) = cursor.region() {
3870            if position >= region.range.end {
3871                return region.range.end;
3872            }
3873            let overshoot = position - region.range.start;
3874            let mut buffer_position = region.buffer_range.start;
3875            buffer_position.add_assign(&overshoot);
3876            let clipped_buffer_position =
3877                clip_buffer_position(&region.buffer, buffer_position, bias);
3878            let mut position = region.range.start;
3879            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3880            position
3881        } else {
3882            D::from_text_summary(&self.text_summary())
3883        }
3884    }
3885
3886    fn convert_dimension<D1, D2>(
3887        &self,
3888        key: D1,
3889        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3890    ) -> D2
3891    where
3892        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3893        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3894    {
3895        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3896        cursor.seek(&DimensionPair { key, value: None });
3897        if let Some(region) = cursor.region() {
3898            if key >= region.range.end.key {
3899                return region.range.end.value.unwrap();
3900            }
3901            let start_key = region.range.start.key;
3902            let start_value = region.range.start.value.unwrap();
3903            let buffer_start_key = region.buffer_range.start.key;
3904            let buffer_start_value = region.buffer_range.start.value.unwrap();
3905            let mut buffer_key = buffer_start_key;
3906            buffer_key.add_assign(&(key - start_key));
3907            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
3908            let mut result = start_value;
3909            result.add_assign(&(buffer_value - buffer_start_value));
3910            result
3911        } else {
3912            D2::from_text_summary(&self.text_summary())
3913        }
3914    }
3915
3916    pub fn point_to_buffer_offset<T: ToOffset>(
3917        &self,
3918        point: T,
3919    ) -> Option<(&BufferSnapshot, usize)> {
3920        let offset = point.to_offset(self);
3921        let mut cursor = self.cursor::<usize>();
3922        cursor.seek(&offset);
3923        let region = cursor.region()?;
3924        let overshoot = offset - region.range.start;
3925        let buffer_offset = region.buffer_range.start + overshoot;
3926        Some((region.buffer, buffer_offset))
3927    }
3928
3929    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
3930        let mut cursor = self.cursor::<Point>();
3931        cursor.seek(&point);
3932        let region = cursor.region()?;
3933        let overshoot = point - region.range.start;
3934        let buffer_offset = region.buffer_range.start + overshoot;
3935        Some((region.buffer, buffer_offset, region.is_main_buffer))
3936    }
3937
3938    pub fn suggested_indents(
3939        &self,
3940        rows: impl IntoIterator<Item = u32>,
3941        cx: &App,
3942    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3943        let mut result = BTreeMap::new();
3944
3945        let mut rows_for_excerpt = Vec::new();
3946        let mut cursor = self.cursor::<Point>();
3947        let mut rows = rows.into_iter().peekable();
3948        let mut prev_row = u32::MAX;
3949        let mut prev_language_indent_size = IndentSize::default();
3950
3951        while let Some(row) = rows.next() {
3952            cursor.seek(&Point::new(row, 0));
3953            let Some(region) = cursor.region() else {
3954                continue;
3955            };
3956
3957            // Retrieve the language and indent size once for each disjoint region being indented.
3958            let single_indent_size = if row.saturating_sub(1) == prev_row {
3959                prev_language_indent_size
3960            } else {
3961                region
3962                    .buffer
3963                    .language_indent_size_at(Point::new(row, 0), cx)
3964            };
3965            prev_language_indent_size = single_indent_size;
3966            prev_row = row;
3967
3968            let start_buffer_row = region.buffer_range.start.row;
3969            let start_multibuffer_row = region.range.start.row;
3970            let end_multibuffer_row = region.range.end.row;
3971
3972            rows_for_excerpt.push(row);
3973            while let Some(next_row) = rows.peek().copied() {
3974                if end_multibuffer_row > next_row {
3975                    rows_for_excerpt.push(next_row);
3976                    rows.next();
3977                } else {
3978                    break;
3979                }
3980            }
3981
3982            let buffer_rows = rows_for_excerpt
3983                .drain(..)
3984                .map(|row| start_buffer_row + row - start_multibuffer_row);
3985            let buffer_indents = region
3986                .buffer
3987                .suggested_indents(buffer_rows, single_indent_size);
3988            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
3989                (
3990                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
3991                    indent,
3992                )
3993            });
3994            result.extend(multibuffer_indents);
3995        }
3996
3997        result
3998    }
3999
4000    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4001        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4002            let mut size = buffer.indent_size_for_line(range.start.row);
4003            size.len = size
4004                .len
4005                .min(range.end.column)
4006                .saturating_sub(range.start.column);
4007            size
4008        } else {
4009            IndentSize::spaces(0)
4010        }
4011    }
4012
4013    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4014        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4015            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4016        } else {
4017            LineIndent::spaces(0)
4018        }
4019    }
4020
4021    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4022        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4023
4024        if self.settings_at(0, cx).extend_comment_on_newline {
4025            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4026                let delimiters = language_scope.line_comment_prefixes();
4027                for delimiter in delimiters {
4028                    if *self
4029                        .chars_at(Point::new(row.0, indent.len() as u32))
4030                        .take(delimiter.chars().count())
4031                        .collect::<String>()
4032                        .as_str()
4033                        == **delimiter
4034                    {
4035                        indent.push_str(&delimiter);
4036                        break;
4037                    }
4038                }
4039            }
4040        }
4041
4042        indent
4043    }
4044
4045    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4046        while row.0 > 0 {
4047            row.0 -= 1;
4048            if !self.is_line_blank(row) {
4049                return Some(row);
4050            }
4051        }
4052        None
4053    }
4054
4055    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4056        if let Some((_, range)) = self.buffer_line_for_row(row) {
4057            range.end.column - range.start.column
4058        } else {
4059            0
4060        }
4061    }
4062
4063    pub fn buffer_line_for_row(
4064        &self,
4065        row: MultiBufferRow,
4066    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4067        let mut cursor = self.cursor::<Point>();
4068        let point = Point::new(row.0, 0);
4069        cursor.seek(&point);
4070        let region = cursor.region()?;
4071        let overshoot = point.min(region.range.end) - region.range.start;
4072        let buffer_point = region.buffer_range.start + overshoot;
4073        if buffer_point.row > region.buffer_range.end.row {
4074            return None;
4075        }
4076        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4077        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4078            .min(region.buffer_range.end);
4079        Some((region.buffer, line_start..line_end))
4080    }
4081
4082    pub fn max_point(&self) -> Point {
4083        self.text_summary().lines
4084    }
4085
4086    pub fn max_row(&self) -> MultiBufferRow {
4087        MultiBufferRow(self.text_summary().lines.row)
4088    }
4089
4090    pub fn text_summary(&self) -> TextSummary {
4091        self.diff_transforms.summary().output
4092    }
4093
4094    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4095    where
4096        D: TextDimension,
4097        O: ToOffset,
4098    {
4099        let range = range.start.to_offset(self)..range.end.to_offset(self);
4100        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4101        cursor.seek(&range.start, Bias::Right, &());
4102
4103        let Some(first_transform) = cursor.item() else {
4104            return D::from_text_summary(&TextSummary::default());
4105        };
4106
4107        let diff_transform_start = cursor.start().0;
4108        let diff_transform_end = cursor.end(&()).0;
4109        let diff_start = range.start;
4110        let start_overshoot = diff_start - diff_transform_start;
4111        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4112
4113        let mut result = match first_transform {
4114            DiffTransform::BufferContent { .. } => {
4115                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4116                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4117                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4118            }
4119            DiffTransform::DeletedHunk {
4120                buffer_id,
4121                base_text_byte_range,
4122                has_trailing_newline,
4123                ..
4124            } => {
4125                let buffer_start = base_text_byte_range.start + start_overshoot;
4126                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4127                let Some(buffer_diff) = self.diffs.get(buffer_id) else {
4128                    panic!("{:?} is in non-existent deleted hunk", range.start)
4129                };
4130
4131                let include_trailing_newline =
4132                    *has_trailing_newline && range.end >= diff_transform_end;
4133                if include_trailing_newline {
4134                    buffer_end -= 1;
4135                }
4136
4137                let mut summary = buffer_diff
4138                    .base_text
4139                    .text_summary_for_range::<D, _>(buffer_start..buffer_end);
4140
4141                if include_trailing_newline {
4142                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4143                }
4144
4145                summary
4146            }
4147        };
4148        if range.end < diff_transform_end {
4149            return result;
4150        }
4151
4152        cursor.next(&());
4153        result.add_assign(&D::from_text_summary(&cursor.summary(
4154            &range.end,
4155            Bias::Right,
4156            &(),
4157        )));
4158
4159        let Some(last_transform) = cursor.item() else {
4160            return result;
4161        };
4162
4163        let overshoot = range.end - cursor.start().0;
4164        let suffix = match last_transform {
4165            DiffTransform::BufferContent { .. } => {
4166                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4167                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4168            }
4169            DiffTransform::DeletedHunk {
4170                base_text_byte_range,
4171                buffer_id,
4172                has_trailing_newline,
4173                ..
4174            } => {
4175                let buffer_end = base_text_byte_range.start + overshoot;
4176                let Some(buffer_diff) = self.diffs.get(buffer_id) else {
4177                    panic!("{:?} is in non-extant deleted hunk", range.end)
4178                };
4179
4180                let mut suffix = buffer_diff
4181                    .base_text
4182                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4183                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4184                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4185                }
4186                suffix
4187            }
4188        };
4189
4190        result.add_assign(&suffix);
4191        result
4192    }
4193
4194    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4195    where
4196        D: TextDimension,
4197    {
4198        // let mut range = range.start..range.end;
4199        let mut summary = D::zero(&());
4200        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4201        cursor.seek(&range.start, Bias::Right, &());
4202        if let Some(excerpt) = cursor.item() {
4203            let mut end_before_newline = cursor.end(&());
4204            if excerpt.has_trailing_newline {
4205                end_before_newline -= ExcerptOffset::new(1);
4206            }
4207
4208            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4209            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4210            let end_in_excerpt =
4211                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4212            summary.add_assign(
4213                &excerpt
4214                    .buffer
4215                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4216            );
4217
4218            if range.end > end_before_newline {
4219                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4220            }
4221
4222            cursor.next(&());
4223        }
4224
4225        if range.end > *cursor.start() {
4226            summary.add_assign(
4227                &cursor
4228                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4229                    .0,
4230            );
4231            if let Some(excerpt) = cursor.item() {
4232                range.end = cmp::max(*cursor.start(), range.end);
4233
4234                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4235                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4236                summary.add_assign(
4237                    &excerpt
4238                        .buffer
4239                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4240                );
4241            }
4242        }
4243
4244        summary
4245    }
4246
4247    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4248    where
4249        D: TextDimension + Ord + Sub<D, Output = D>,
4250    {
4251        self.summaries_for_anchors([anchor])[0]
4252    }
4253
4254    fn resolve_summary_for_anchor<D>(
4255        &self,
4256        anchor: &Anchor,
4257        excerpt_position: D,
4258        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4259    ) -> D
4260    where
4261        D: TextDimension + Ord + Sub<D, Output = D>,
4262    {
4263        loop {
4264            let transform_end_position = diff_transforms.end(&()).0 .0;
4265            let at_transform_end =
4266                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4267            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4268                diff_transforms.next(&());
4269                continue;
4270            }
4271
4272            let mut position = diff_transforms.start().1 .0;
4273            match diff_transforms.item() {
4274                Some(DiffTransform::DeletedHunk {
4275                    buffer_id,
4276                    base_text_byte_range,
4277                    ..
4278                }) => {
4279                    let mut in_deleted_hunk = false;
4280                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4281                        if let Some(diff) = self.diffs.get(buffer_id) {
4282                            if diff.base_text.can_resolve(&diff_base_anchor) {
4283                                let base_text_offset = diff_base_anchor.to_offset(&diff.base_text);
4284                                if base_text_offset >= base_text_byte_range.start
4285                                    && base_text_offset <= base_text_byte_range.end
4286                                {
4287                                    let position_in_hunk =
4288                                        diff.base_text.text_summary_for_range::<D, _>(
4289                                            base_text_byte_range.start..base_text_offset,
4290                                        );
4291                                    position.add_assign(&position_in_hunk);
4292                                    in_deleted_hunk = true;
4293                                } else if at_transform_end {
4294                                    diff_transforms.next(&());
4295                                    continue;
4296                                }
4297                            }
4298                        }
4299                    }
4300                    if !in_deleted_hunk {
4301                        position = diff_transforms.end(&()).1 .0;
4302                    }
4303                }
4304                _ => {
4305                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4306                        diff_transforms.next(&());
4307                        continue;
4308                    }
4309                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4310                    position.add_assign(&overshoot);
4311                }
4312            }
4313
4314            return position;
4315        }
4316    }
4317
4318    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4319        let mut cursor = self
4320            .excerpts
4321            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4322        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4323
4324        cursor.seek(&Some(locator), Bias::Left, &());
4325        if cursor.item().is_none() {
4326            cursor.next(&());
4327        }
4328
4329        let mut position = cursor.start().1;
4330        if let Some(excerpt) = cursor.item() {
4331            if excerpt.id == anchor.excerpt_id {
4332                let excerpt_buffer_start = excerpt
4333                    .buffer
4334                    .offset_for_anchor(&excerpt.range.context.start);
4335                let excerpt_buffer_end =
4336                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4337                let buffer_position = cmp::min(
4338                    excerpt_buffer_end,
4339                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4340                );
4341                if buffer_position > excerpt_buffer_start {
4342                    position.value += buffer_position - excerpt_buffer_start;
4343                }
4344            }
4345        }
4346        position
4347    }
4348
4349    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4350    where
4351        D: TextDimension + Ord + Sub<D, Output = D>,
4352        I: 'a + IntoIterator<Item = &'a Anchor>,
4353    {
4354        let mut anchors = anchors.into_iter().peekable();
4355        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4356        let mut diff_transforms_cursor = self
4357            .diff_transforms
4358            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4359        diff_transforms_cursor.next(&());
4360
4361        let mut summaries = Vec::new();
4362        while let Some(anchor) = anchors.peek() {
4363            let excerpt_id = anchor.excerpt_id;
4364            let excerpt_anchors = iter::from_fn(|| {
4365                let anchor = anchors.peek()?;
4366                if anchor.excerpt_id == excerpt_id {
4367                    Some(anchors.next().unwrap())
4368                } else {
4369                    None
4370                }
4371            });
4372
4373            let locator = self.excerpt_locator_for_id(excerpt_id);
4374            cursor.seek_forward(locator, Bias::Left, &());
4375            if cursor.item().is_none() {
4376                cursor.next(&());
4377            }
4378
4379            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4380            if let Some(excerpt) = cursor.item().filter(|excerpt| excerpt.id == excerpt_id) {
4381                let excerpt_buffer_start =
4382                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4383                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4384                for (buffer_summary, anchor) in excerpt
4385                    .buffer
4386                    .summaries_for_anchors_with_payload::<D, _, _>(
4387                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4388                    )
4389                {
4390                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4391                    let mut position = excerpt_start_position;
4392                    if summary > excerpt_buffer_start {
4393                        position.add_assign(&(summary - excerpt_buffer_start));
4394                    }
4395
4396                    if position > diff_transforms_cursor.start().0 .0 {
4397                        diff_transforms_cursor.seek_forward(
4398                            &ExcerptDimension(position),
4399                            Bias::Left,
4400                            &(),
4401                        );
4402                    }
4403
4404                    summaries.push(self.resolve_summary_for_anchor(
4405                        anchor,
4406                        position,
4407                        &mut diff_transforms_cursor,
4408                    ));
4409                }
4410            } else {
4411                diff_transforms_cursor.seek_forward(
4412                    &ExcerptDimension(excerpt_start_position),
4413                    Bias::Left,
4414                    &(),
4415                );
4416                let position = self.resolve_summary_for_anchor(
4417                    &Anchor::max(),
4418                    excerpt_start_position,
4419                    &mut diff_transforms_cursor,
4420                );
4421                summaries.extend(excerpt_anchors.map(|_| position));
4422            }
4423        }
4424
4425        summaries
4426    }
4427
4428    pub fn dimensions_from_points<'a, D>(
4429        &'a self,
4430        points: impl 'a + IntoIterator<Item = Point>,
4431    ) -> impl 'a + Iterator<Item = D>
4432    where
4433        D: TextDimension + Sub<D, Output = D>,
4434    {
4435        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4436        cursor.seek(&DimensionPair {
4437            key: Point::default(),
4438            value: None,
4439        });
4440        let mut points = points.into_iter();
4441        iter::from_fn(move || {
4442            let point = points.next()?;
4443
4444            cursor.seek_forward(&DimensionPair {
4445                key: point,
4446                value: None,
4447            });
4448
4449            if let Some(region) = cursor.region() {
4450                let overshoot = point - region.range.start.key;
4451                let buffer_point = region.buffer_range.start.key + overshoot;
4452                let mut position = region.range.start.value.unwrap();
4453                position.add_assign(
4454                    &region
4455                        .buffer
4456                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4457                );
4458                return Some(position);
4459            } else {
4460                return Some(D::from_text_summary(&self.text_summary()));
4461            }
4462        })
4463    }
4464
4465    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4466    where
4467        I: 'a + IntoIterator<Item = &'a Anchor>,
4468    {
4469        let mut anchors = anchors.into_iter().enumerate().peekable();
4470        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4471        cursor.next(&());
4472
4473        let mut result = Vec::new();
4474
4475        while let Some((_, anchor)) = anchors.peek() {
4476            let old_excerpt_id = anchor.excerpt_id;
4477
4478            // Find the location where this anchor's excerpt should be.
4479            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4480            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4481
4482            if cursor.item().is_none() {
4483                cursor.next(&());
4484            }
4485
4486            let next_excerpt = cursor.item();
4487            let prev_excerpt = cursor.prev_item();
4488
4489            // Process all of the anchors for this excerpt.
4490            while let Some((_, anchor)) = anchors.peek() {
4491                if anchor.excerpt_id != old_excerpt_id {
4492                    break;
4493                }
4494                let (anchor_ix, anchor) = anchors.next().unwrap();
4495                let mut anchor = *anchor;
4496
4497                // Leave min and max anchors unchanged if invalid or
4498                // if the old excerpt still exists at this location
4499                let mut kept_position = next_excerpt
4500                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4501                    || old_excerpt_id == ExcerptId::max()
4502                    || old_excerpt_id == ExcerptId::min();
4503
4504                // If the old excerpt no longer exists at this location, then attempt to
4505                // find an equivalent position for this anchor in an adjacent excerpt.
4506                if !kept_position {
4507                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4508                        if excerpt.contains(&anchor) {
4509                            anchor.excerpt_id = excerpt.id;
4510                            kept_position = true;
4511                            break;
4512                        }
4513                    }
4514                }
4515
4516                // If there's no adjacent excerpt that contains the anchor's position,
4517                // then report that the anchor has lost its position.
4518                if !kept_position {
4519                    anchor = if let Some(excerpt) = next_excerpt {
4520                        let mut text_anchor = excerpt
4521                            .range
4522                            .context
4523                            .start
4524                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4525                        if text_anchor
4526                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4527                            .is_gt()
4528                        {
4529                            text_anchor = excerpt.range.context.end;
4530                        }
4531                        Anchor {
4532                            buffer_id: Some(excerpt.buffer_id),
4533                            excerpt_id: excerpt.id,
4534                            text_anchor,
4535                            diff_base_anchor: None,
4536                        }
4537                    } else if let Some(excerpt) = prev_excerpt {
4538                        let mut text_anchor = excerpt
4539                            .range
4540                            .context
4541                            .end
4542                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4543                        if text_anchor
4544                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4545                            .is_lt()
4546                        {
4547                            text_anchor = excerpt.range.context.start;
4548                        }
4549                        Anchor {
4550                            buffer_id: Some(excerpt.buffer_id),
4551                            excerpt_id: excerpt.id,
4552                            text_anchor,
4553                            diff_base_anchor: None,
4554                        }
4555                    } else if anchor.text_anchor.bias == Bias::Left {
4556                        Anchor::min()
4557                    } else {
4558                        Anchor::max()
4559                    };
4560                }
4561
4562                result.push((anchor_ix, anchor, kept_position));
4563            }
4564        }
4565        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4566        result
4567    }
4568
4569    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4570        self.anchor_at(position, Bias::Left)
4571    }
4572
4573    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4574        self.anchor_at(position, Bias::Right)
4575    }
4576
4577    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4578        let offset = position.to_offset(self);
4579
4580        // Find the given position in the diff transforms. Determine the corresponding
4581        // offset in the excerpts, and whether the position is within a deleted hunk.
4582        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4583        diff_transforms.seek(&offset, Bias::Right, &());
4584
4585        if offset == diff_transforms.start().0 && bias == Bias::Left {
4586            if let Some(prev_item) = diff_transforms.prev_item() {
4587                match prev_item {
4588                    DiffTransform::DeletedHunk { .. } => {
4589                        diff_transforms.prev(&());
4590                    }
4591                    _ => {}
4592                }
4593            }
4594        }
4595        let offset_in_transform = offset - diff_transforms.start().0;
4596        let mut excerpt_offset = diff_transforms.start().1;
4597        let mut diff_base_anchor = None;
4598        if let Some(DiffTransform::DeletedHunk {
4599            buffer_id,
4600            base_text_byte_range,
4601            has_trailing_newline,
4602            ..
4603        }) = diff_transforms.item()
4604        {
4605            let diff_base = self.diffs.get(buffer_id).expect("missing diff base");
4606            if offset_in_transform > base_text_byte_range.len() {
4607                debug_assert!(*has_trailing_newline);
4608                bias = Bias::Right;
4609            } else {
4610                diff_base_anchor = Some(
4611                    diff_base
4612                        .base_text
4613                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4614                );
4615                bias = Bias::Left;
4616            }
4617        } else {
4618            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4619        };
4620
4621        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4622            return Anchor {
4623                buffer_id: Some(buffer_id),
4624                excerpt_id: *excerpt_id,
4625                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4626                diff_base_anchor,
4627            };
4628        }
4629
4630        let mut excerpts = self
4631            .excerpts
4632            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4633        excerpts.seek(&excerpt_offset, Bias::Right, &());
4634        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4635            excerpts.prev(&());
4636        }
4637        if let Some(excerpt) = excerpts.item() {
4638            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4639            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4640                overshoot -= 1;
4641                bias = Bias::Right;
4642            }
4643
4644            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4645            let text_anchor =
4646                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4647            Anchor {
4648                buffer_id: Some(excerpt.buffer_id),
4649                excerpt_id: excerpt.id,
4650                text_anchor,
4651                diff_base_anchor,
4652            }
4653        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4654            Anchor::min()
4655        } else {
4656            Anchor::max()
4657        }
4658    }
4659
4660    /// Returns an anchor for the given excerpt and text anchor,
4661    /// returns None if the excerpt_id is no longer valid.
4662    pub fn anchor_in_excerpt(
4663        &self,
4664        excerpt_id: ExcerptId,
4665        text_anchor: text::Anchor,
4666    ) -> Option<Anchor> {
4667        let locator = self.excerpt_locator_for_id(excerpt_id);
4668        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4669        cursor.seek(locator, Bias::Left, &());
4670        if let Some(excerpt) = cursor.item() {
4671            if excerpt.id == excerpt_id {
4672                let text_anchor = excerpt.clip_anchor(text_anchor);
4673                drop(cursor);
4674                return Some(Anchor {
4675                    buffer_id: Some(excerpt.buffer_id),
4676                    excerpt_id,
4677                    text_anchor,
4678                    diff_base_anchor: None,
4679                });
4680            }
4681        }
4682        None
4683    }
4684
4685    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4686        Some(self.excerpt(excerpt_id)?.range.context.clone())
4687    }
4688
4689    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4690        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4691            true
4692        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4693            excerpt.buffer.can_resolve(&anchor.text_anchor)
4694        } else {
4695            false
4696        }
4697    }
4698
4699    pub fn excerpts(
4700        &self,
4701    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4702        self.excerpts
4703            .iter()
4704            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4705    }
4706
4707    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4708        let excerpts = self.excerpts.cursor(&());
4709        let diff_transforms = self.diff_transforms.cursor(&());
4710        MultiBufferCursor {
4711            excerpts,
4712            diff_transforms,
4713            diffs: &self.diffs,
4714            cached_region: None,
4715        }
4716    }
4717
4718    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4719        let start_locator = self.excerpt_locator_for_id(id);
4720        let mut excerpts = self
4721            .excerpts
4722            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4723        excerpts.seek(&Some(start_locator), Bias::Left, &());
4724        excerpts.prev(&());
4725
4726        let mut diff_transforms = self
4727            .diff_transforms
4728            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4729        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4730        if diff_transforms.end(&()).1 < excerpts.start().1 {
4731            diff_transforms.next(&());
4732        }
4733
4734        let excerpt = excerpts.item()?;
4735        Some(MultiBufferExcerpt {
4736            excerpt,
4737            offset: diff_transforms.start().0 .0,
4738            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4739            excerpt_offset: excerpts.start().1.clone(),
4740            diff_transforms,
4741        })
4742    }
4743
4744    pub fn excerpt_boundaries_in_range<R, T>(
4745        &self,
4746        range: R,
4747    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4748    where
4749        R: RangeBounds<T>,
4750        T: ToOffset,
4751    {
4752        let start_offset;
4753        let start = match range.start_bound() {
4754            Bound::Included(start) => {
4755                start_offset = start.to_offset(self);
4756                Bound::Included(start_offset)
4757            }
4758            Bound::Excluded(_) => {
4759                panic!("not supported")
4760            }
4761            Bound::Unbounded => {
4762                start_offset = 0;
4763                Bound::Unbounded
4764            }
4765        };
4766        let end = match range.end_bound() {
4767            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4768            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4769            Bound::Unbounded => Bound::Unbounded,
4770        };
4771        let bounds = (start, end);
4772
4773        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4774        cursor.seek(&DimensionPair {
4775            key: start_offset,
4776            value: None,
4777        });
4778
4779        if cursor
4780            .region()
4781            .is_some_and(|region| bounds.contains(&region.range.start.key))
4782        {
4783            cursor.prev_excerpt();
4784        } else {
4785            cursor.seek_to_start_of_current_excerpt();
4786        }
4787        let mut prev_region = cursor.region();
4788
4789        cursor.next_excerpt();
4790
4791        let mut visited_end = false;
4792        iter::from_fn(move || {
4793            if self.singleton {
4794                return None;
4795            }
4796
4797            let next_region = cursor.region();
4798            cursor.next_excerpt();
4799
4800            let next_region_start = if let Some(region) = &next_region {
4801                if !bounds.contains(&region.range.start.key) {
4802                    return None;
4803                }
4804                region.range.start.value.unwrap()
4805            } else {
4806                if !bounds.contains(&self.len()) {
4807                    return None;
4808                }
4809                self.max_point()
4810            };
4811            let next_region_end = if let Some(region) = cursor.region() {
4812                region.range.start.value.unwrap()
4813            } else {
4814                self.max_point()
4815            };
4816
4817            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4818                id: region.excerpt.id,
4819                buffer: region.excerpt.buffer.clone(),
4820                buffer_id: region.excerpt.buffer_id,
4821                range: region.excerpt.range.clone(),
4822                end_row: MultiBufferRow(next_region_start.row),
4823            });
4824
4825            let next = next_region.as_ref().map(|region| ExcerptInfo {
4826                id: region.excerpt.id,
4827                buffer: region.excerpt.buffer.clone(),
4828                buffer_id: region.excerpt.buffer_id,
4829                range: region.excerpt.range.clone(),
4830                end_row: if region.excerpt.has_trailing_newline {
4831                    MultiBufferRow(next_region_end.row - 1)
4832                } else {
4833                    MultiBufferRow(next_region_end.row)
4834                },
4835            });
4836
4837            if next.is_none() {
4838                if visited_end {
4839                    return None;
4840                } else {
4841                    visited_end = true;
4842                }
4843            }
4844
4845            let row = MultiBufferRow(next_region_start.row);
4846
4847            prev_region = next_region;
4848
4849            Some(ExcerptBoundary { row, prev, next })
4850        })
4851    }
4852
4853    pub fn edit_count(&self) -> usize {
4854        self.edit_count
4855    }
4856
4857    pub fn non_text_state_update_count(&self) -> usize {
4858        self.non_text_state_update_count
4859    }
4860
4861    /// Returns the smallest enclosing bracket ranges containing the given range or
4862    /// None if no brackets contain range or the range is not contained in a single
4863    /// excerpt
4864    ///
4865    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4866    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4867        &self,
4868        range: Range<T>,
4869        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4870    ) -> Option<(Range<usize>, Range<usize>)> {
4871        let range = range.start.to_offset(self)..range.end.to_offset(self);
4872        let mut excerpt = self.excerpt_containing(range.clone())?;
4873        let buffer = excerpt.buffer();
4874        let excerpt_buffer_range = excerpt.buffer_range();
4875
4876        // Filter to ranges contained in the excerpt
4877        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4878            excerpt_buffer_range.contains(&open.start)
4879                && excerpt_buffer_range.contains(&close.end)
4880                && range_filter.map_or(true, |filter| filter(buffer, open, close))
4881        };
4882
4883        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4884            excerpt.map_range_to_buffer(range),
4885            Some(&range_filter),
4886        )?;
4887
4888        Some((
4889            excerpt.map_range_from_buffer(open),
4890            excerpt.map_range_from_buffer(close),
4891        ))
4892    }
4893
4894    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4895    /// not contained in a single excerpt
4896    pub fn enclosing_bracket_ranges<T: ToOffset>(
4897        &self,
4898        range: Range<T>,
4899    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4900        let range = range.start.to_offset(self)..range.end.to_offset(self);
4901        let mut excerpt = self.excerpt_containing(range.clone())?;
4902
4903        Some(
4904            excerpt
4905                .buffer()
4906                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4907                .filter_map(move |(open, close)| {
4908                    if excerpt.contains_buffer_range(open.start..close.end) {
4909                        Some((
4910                            excerpt.map_range_from_buffer(open),
4911                            excerpt.map_range_from_buffer(close),
4912                        ))
4913                    } else {
4914                        None
4915                    }
4916                }),
4917        )
4918    }
4919
4920    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4921    /// not contained in a single excerpt
4922    pub fn text_object_ranges<T: ToOffset>(
4923        &self,
4924        range: Range<T>,
4925        options: TreeSitterOptions,
4926    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4927        let range = range.start.to_offset(self)..range.end.to_offset(self);
4928        self.excerpt_containing(range.clone())
4929            .map(|mut excerpt| {
4930                excerpt
4931                    .buffer()
4932                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4933                    .filter_map(move |(range, text_object)| {
4934                        if excerpt.contains_buffer_range(range.clone()) {
4935                            Some((excerpt.map_range_from_buffer(range), text_object))
4936                        } else {
4937                            None
4938                        }
4939                    })
4940            })
4941            .into_iter()
4942            .flatten()
4943    }
4944
4945    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4946    /// not contained in a single excerpt
4947    pub fn bracket_ranges<T: ToOffset>(
4948        &self,
4949        range: Range<T>,
4950    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4951        let range = range.start.to_offset(self)..range.end.to_offset(self);
4952        let mut excerpt = self.excerpt_containing(range.clone())?;
4953
4954        Some(
4955            excerpt
4956                .buffer()
4957                .bracket_ranges(excerpt.map_range_to_buffer(range))
4958                .filter_map(move |(start_bracket_range, close_bracket_range)| {
4959                    let buffer_range = start_bracket_range.start..close_bracket_range.end;
4960                    if excerpt.contains_buffer_range(buffer_range) {
4961                        Some((
4962                            excerpt.map_range_from_buffer(start_bracket_range),
4963                            excerpt.map_range_from_buffer(close_bracket_range),
4964                        ))
4965                    } else {
4966                        None
4967                    }
4968                }),
4969        )
4970    }
4971
4972    pub fn redacted_ranges<'a, T: ToOffset>(
4973        &'a self,
4974        range: Range<T>,
4975        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
4976    ) -> impl Iterator<Item = Range<usize>> + 'a {
4977        let range = range.start.to_offset(self)..range.end.to_offset(self);
4978        self.lift_buffer_metadata(range, move |buffer, range| {
4979            if redaction_enabled(buffer.file()) {
4980                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
4981            } else {
4982                None
4983            }
4984        })
4985        .map(|(range, _, _)| range)
4986    }
4987
4988    pub fn runnable_ranges(
4989        &self,
4990        range: Range<Anchor>,
4991    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
4992        let range = range.start.to_offset(self)..range.end.to_offset(self);
4993        self.lift_buffer_metadata(range, move |buffer, range| {
4994            Some(
4995                buffer
4996                    .runnable_ranges(range.clone())
4997                    .filter(move |runnable| {
4998                        runnable.run_range.start >= range.start
4999                            && runnable.run_range.end < range.end
5000                    })
5001                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5002            )
5003        })
5004        .map(|(run_range, runnable, _)| language::RunnableRange {
5005            run_range,
5006            ..runnable
5007        })
5008    }
5009
5010    pub fn line_indents(
5011        &self,
5012        start_row: MultiBufferRow,
5013        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5014    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5015        let max_point = self.max_point();
5016        let mut cursor = self.cursor::<Point>();
5017        cursor.seek(&Point::new(start_row.0, 0));
5018        iter::from_fn(move || {
5019            let mut region = cursor.region()?;
5020            while !buffer_filter(&region.excerpt.buffer) {
5021                cursor.next();
5022                region = cursor.region()?;
5023            }
5024            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5025            let buffer_start_row =
5026                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5027
5028            let buffer_end_row = if region.is_main_buffer
5029                && (region.has_trailing_newline || region.range.end == max_point)
5030            {
5031                region.buffer_range.end.row
5032            } else {
5033                region.buffer_range.end.row.saturating_sub(1)
5034            };
5035
5036            let line_indents = region
5037                .buffer
5038                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5039            cursor.next();
5040            return Some(line_indents.map(move |(buffer_row, indent)| {
5041                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5042                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5043            }));
5044        })
5045        .flatten()
5046    }
5047
5048    pub fn reversed_line_indents(
5049        &self,
5050        end_row: MultiBufferRow,
5051        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5052    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5053        let max_point = self.max_point();
5054        let mut cursor = self.cursor::<Point>();
5055        cursor.seek(&Point::new(end_row.0, 0));
5056        iter::from_fn(move || {
5057            let mut region = cursor.region()?;
5058            while !buffer_filter(&region.excerpt.buffer) {
5059                cursor.prev();
5060                region = cursor.region()?;
5061            }
5062
5063            let buffer_start_row = region.buffer_range.start.row;
5064            let buffer_end_row = if region.is_main_buffer
5065                && (region.has_trailing_newline || region.range.end == max_point)
5066            {
5067                region.buffer_range.end.row + 1
5068            } else {
5069                region.buffer_range.end.row
5070            };
5071
5072            let overshoot = end_row.0 - region.range.start.row;
5073            let buffer_end_row =
5074                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5075
5076            let line_indents = region
5077                .buffer
5078                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5079            cursor.prev();
5080            return Some(line_indents.map(move |(buffer_row, indent)| {
5081                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5082                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5083            }));
5084        })
5085        .flatten()
5086    }
5087
5088    pub async fn enclosing_indent(
5089        &self,
5090        mut target_row: MultiBufferRow,
5091    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5092        let max_row = MultiBufferRow(self.max_point().row);
5093        if target_row >= max_row {
5094            return None;
5095        }
5096
5097        let mut target_indent = self.line_indent_for_row(target_row);
5098
5099        // If the current row is at the start of an indented block, we want to return this
5100        // block as the enclosing indent.
5101        if !target_indent.is_line_empty() && target_row < max_row {
5102            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5103            if !next_line_indent.is_line_empty()
5104                && target_indent.raw_len() < next_line_indent.raw_len()
5105            {
5106                target_indent = next_line_indent;
5107                target_row.0 += 1;
5108            }
5109        }
5110
5111        const SEARCH_ROW_LIMIT: u32 = 25000;
5112        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5113        const YIELD_INTERVAL: u32 = 100;
5114
5115        let mut accessed_row_counter = 0;
5116
5117        // If there is a blank line at the current row, search for the next non indented lines
5118        if target_indent.is_line_empty() {
5119            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5120            let end =
5121                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5122
5123            let mut non_empty_line_above = None;
5124            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5125                if row < start {
5126                    break;
5127                }
5128                accessed_row_counter += 1;
5129                if accessed_row_counter == YIELD_INTERVAL {
5130                    accessed_row_counter = 0;
5131                    yield_now().await;
5132                }
5133                if !indent.is_line_empty() {
5134                    non_empty_line_above = Some((row, indent));
5135                    break;
5136                }
5137            }
5138
5139            let mut non_empty_line_below = None;
5140            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5141                if row > end {
5142                    break;
5143                }
5144                accessed_row_counter += 1;
5145                if accessed_row_counter == YIELD_INTERVAL {
5146                    accessed_row_counter = 0;
5147                    yield_now().await;
5148                }
5149                if !indent.is_line_empty() {
5150                    non_empty_line_below = Some((row, indent));
5151                    break;
5152                }
5153            }
5154
5155            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5156                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5157                    if above_indent.raw_len() >= below_indent.raw_len() {
5158                        (above_row, above_indent)
5159                    } else {
5160                        (below_row, below_indent)
5161                    }
5162                }
5163                (Some(above), None) => above,
5164                (None, Some(below)) => below,
5165                _ => return None,
5166            };
5167
5168            target_indent = indent;
5169            target_row = row;
5170        }
5171
5172        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5173        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5174
5175        let mut start_indent = None;
5176        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5177            if row < start {
5178                break;
5179            }
5180            accessed_row_counter += 1;
5181            if accessed_row_counter == YIELD_INTERVAL {
5182                accessed_row_counter = 0;
5183                yield_now().await;
5184            }
5185            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5186                start_indent = Some((row, indent));
5187                break;
5188            }
5189        }
5190        let (start_row, start_indent_size) = start_indent?;
5191
5192        let mut end_indent = (end, None);
5193        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5194            if row > end {
5195                break;
5196            }
5197            accessed_row_counter += 1;
5198            if accessed_row_counter == YIELD_INTERVAL {
5199                accessed_row_counter = 0;
5200                yield_now().await;
5201            }
5202            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5203                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5204                break;
5205            }
5206        }
5207        let (end_row, end_indent_size) = end_indent;
5208
5209        let indent = if let Some(end_indent_size) = end_indent_size {
5210            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5211                start_indent_size
5212            } else {
5213                end_indent_size
5214            }
5215        } else {
5216            start_indent_size
5217        };
5218
5219        Some((start_row..end_row, indent))
5220    }
5221
5222    pub fn indent_guides_in_range<T: ToPoint>(
5223        &self,
5224        range: Range<T>,
5225        ignore_disabled_for_language: bool,
5226        cx: &App,
5227    ) -> impl Iterator<Item = IndentGuide> {
5228        let range = range.start.to_point(self)..range.end.to_point(self);
5229        let start_row = MultiBufferRow(range.start.row);
5230        let end_row = MultiBufferRow(range.end.row);
5231
5232        let mut row_indents = self.line_indents(start_row, |buffer| {
5233            let settings =
5234                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5235            settings.indent_guides.enabled || ignore_disabled_for_language
5236        });
5237
5238        let mut result = Vec::new();
5239        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5240
5241        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5242            if first_row > end_row {
5243                break;
5244            }
5245            let current_depth = indent_stack.len() as u32;
5246
5247            let settings =
5248                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5249            let tab_size = settings.tab_size.get() as u32;
5250
5251            // When encountering empty, continue until found useful line indent
5252            // then add to the indent stack with the depth found
5253            let mut found_indent = false;
5254            let mut last_row = first_row;
5255            if line_indent.is_line_empty() {
5256                while !found_indent {
5257                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5258                        break;
5259                    };
5260                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5261                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5262                        break;
5263                    }
5264
5265                    if new_line_indent.is_line_empty() {
5266                        continue;
5267                    }
5268                    last_row = target_row.min(end_row);
5269                    line_indent = new_line_indent;
5270                    found_indent = true;
5271                    break;
5272                }
5273            } else {
5274                found_indent = true
5275            }
5276
5277            let depth = if found_indent {
5278                line_indent.len(tab_size) / tab_size
5279                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5280            } else {
5281                current_depth
5282            };
5283
5284            match depth.cmp(&current_depth) {
5285                cmp::Ordering::Less => {
5286                    for _ in 0..(current_depth - depth) {
5287                        let mut indent = indent_stack.pop().unwrap();
5288                        if last_row != first_row {
5289                            // In this case, we landed on an empty row, had to seek forward,
5290                            // and discovered that the indent we where on is ending.
5291                            // This means that the last display row must
5292                            // be on line that ends this indent range, so we
5293                            // should display the range up to the first non-empty line
5294                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5295                        }
5296
5297                        result.push(indent)
5298                    }
5299                }
5300                cmp::Ordering::Greater => {
5301                    for next_depth in current_depth..depth {
5302                        indent_stack.push(IndentGuide {
5303                            buffer_id: buffer.remote_id(),
5304                            start_row: first_row,
5305                            end_row: last_row,
5306                            depth: next_depth,
5307                            tab_size,
5308                            settings: settings.indent_guides,
5309                        });
5310                    }
5311                }
5312                _ => {}
5313            }
5314
5315            for indent in indent_stack.iter_mut() {
5316                indent.end_row = last_row;
5317            }
5318        }
5319
5320        result.extend(indent_stack);
5321        result.into_iter()
5322    }
5323
5324    pub fn trailing_excerpt_update_count(&self) -> usize {
5325        self.trailing_excerpt_update_count
5326    }
5327
5328    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5329        self.point_to_buffer_offset(point)
5330            .and_then(|(buffer, _)| buffer.file())
5331    }
5332
5333    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5334        self.point_to_buffer_offset(point)
5335            .and_then(|(buffer, offset)| buffer.language_at(offset))
5336    }
5337
5338    pub fn settings_at<'a, T: ToOffset>(
5339        &'a self,
5340        point: T,
5341        cx: &'a App,
5342    ) -> Cow<'a, LanguageSettings> {
5343        let mut language = None;
5344        let mut file = None;
5345        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5346            language = buffer.language_at(offset);
5347            file = buffer.file();
5348        }
5349        language_settings(language.map(|l| l.name()), file, cx)
5350    }
5351
5352    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5353        self.point_to_buffer_offset(point)
5354            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5355    }
5356
5357    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5358        self.point_to_buffer_offset(point)
5359            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5360            .unwrap_or_default()
5361    }
5362
5363    pub fn language_indent_size_at<T: ToOffset>(
5364        &self,
5365        position: T,
5366        cx: &App,
5367    ) -> Option<IndentSize> {
5368        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5369        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5370    }
5371
5372    pub fn is_dirty(&self) -> bool {
5373        self.is_dirty
5374    }
5375
5376    pub fn has_deleted_file(&self) -> bool {
5377        self.has_deleted_file
5378    }
5379
5380    pub fn has_conflict(&self) -> bool {
5381        self.has_conflict
5382    }
5383
5384    pub fn has_diagnostics(&self) -> bool {
5385        self.excerpts
5386            .iter()
5387            .any(|excerpt| excerpt.buffer.has_diagnostics())
5388    }
5389
5390    pub fn diagnostic_group(
5391        &self,
5392        buffer_id: BufferId,
5393        group_id: usize,
5394    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5395        self.lift_buffer_metadata(0..self.len(), move |buffer, _| {
5396            if buffer.remote_id() != buffer_id {
5397                return None;
5398            };
5399            Some(
5400                buffer
5401                    .diagnostic_group(group_id)
5402                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5403            )
5404        })
5405        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5406    }
5407
5408    pub fn diagnostics_in_range<'a, T, O>(
5409        &'a self,
5410        range: Range<T>,
5411    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
5412    where
5413        T: 'a + ToOffset,
5414        O: 'a + text::FromAnchor + Copy + TextDimension + Ord + Sub<O, Output = O> + fmt::Debug,
5415    {
5416        let range = range.start.to_offset(self)..range.end.to_offset(self);
5417        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5418            Some(
5419                buffer
5420                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5421                    .map(|entry| (entry.range, entry.diagnostic)),
5422            )
5423        })
5424        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5425    }
5426
5427    pub fn syntax_ancestor<T: ToOffset>(
5428        &self,
5429        range: Range<T>,
5430    ) -> Option<(tree_sitter::Node, Range<usize>)> {
5431        let range = range.start.to_offset(self)..range.end.to_offset(self);
5432        let mut excerpt = self.excerpt_containing(range.clone())?;
5433        let node = excerpt
5434            .buffer()
5435            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5436        Some((node, excerpt.map_range_from_buffer(node.byte_range())))
5437    }
5438
5439    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5440        let (excerpt_id, _, buffer) = self.as_singleton()?;
5441        let outline = buffer.outline(theme)?;
5442        Some(Outline::new(
5443            outline
5444                .items
5445                .into_iter()
5446                .flat_map(|item| {
5447                    Some(OutlineItem {
5448                        depth: item.depth,
5449                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5450                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5451                        text: item.text,
5452                        highlight_ranges: item.highlight_ranges,
5453                        name_ranges: item.name_ranges,
5454                        body_range: item.body_range.and_then(|body_range| {
5455                            Some(
5456                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5457                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5458                            )
5459                        }),
5460                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5461                            Some(
5462                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5463                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5464                            )
5465                        }),
5466                    })
5467                })
5468                .collect(),
5469        ))
5470    }
5471
5472    pub fn symbols_containing<T: ToOffset>(
5473        &self,
5474        offset: T,
5475        theme: Option<&SyntaxTheme>,
5476    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5477        let anchor = self.anchor_before(offset);
5478        let excerpt_id = anchor.excerpt_id;
5479        let excerpt = self.excerpt(excerpt_id)?;
5480        Some((
5481            excerpt.buffer_id,
5482            excerpt
5483                .buffer
5484                .symbols_containing(anchor.text_anchor, theme)
5485                .into_iter()
5486                .flatten()
5487                .flat_map(|item| {
5488                    Some(OutlineItem {
5489                        depth: item.depth,
5490                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5491                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5492                        text: item.text,
5493                        highlight_ranges: item.highlight_ranges,
5494                        name_ranges: item.name_ranges,
5495                        body_range: item.body_range.and_then(|body_range| {
5496                            Some(
5497                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5498                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5499                            )
5500                        }),
5501                        annotation_range: item.annotation_range.and_then(|body_range| {
5502                            Some(
5503                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5504                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5505                            )
5506                        }),
5507                    })
5508                })
5509                .collect(),
5510        ))
5511    }
5512
5513    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5514        if id == ExcerptId::min() {
5515            Locator::min_ref()
5516        } else if id == ExcerptId::max() {
5517            Locator::max_ref()
5518        } else {
5519            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5520            cursor.seek(&id, Bias::Left, &());
5521            if let Some(entry) = cursor.item() {
5522                if entry.id == id {
5523                    return &entry.locator;
5524                }
5525            }
5526            panic!("invalid excerpt id {:?}", id)
5527        }
5528    }
5529
5530    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5531    fn excerpt_locators_for_ids(
5532        &self,
5533        ids: impl IntoIterator<Item = ExcerptId>,
5534    ) -> SmallVec<[Locator; 1]> {
5535        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5536        sorted_ids.sort_unstable();
5537        let mut locators = SmallVec::new();
5538
5539        while sorted_ids.last() == Some(&ExcerptId::max()) {
5540            sorted_ids.pop();
5541            if let Some(mapping) = self.excerpt_ids.last() {
5542                locators.push(mapping.locator.clone());
5543            }
5544        }
5545
5546        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5547        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5548            sorted_ids.next();
5549            if let Some(mapping) = self.excerpt_ids.first() {
5550                locators.push(mapping.locator.clone());
5551            }
5552        }
5553
5554        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5555        for id in sorted_ids {
5556            if cursor.seek_forward(&id, Bias::Left, &()) {
5557                locators.push(cursor.item().unwrap().locator.clone());
5558            } else {
5559                panic!("invalid excerpt id {:?}", id);
5560            }
5561        }
5562
5563        locators.sort_unstable();
5564        locators
5565    }
5566
5567    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5568        Some(self.excerpt(excerpt_id)?.buffer_id)
5569    }
5570
5571    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5572        Some(&self.excerpt(excerpt_id)?.buffer)
5573    }
5574
5575    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5576        let mut cursor = self
5577            .excerpts
5578            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5579        let locator = self.excerpt_locator_for_id(excerpt_id);
5580        if cursor.seek(&Some(locator), Bias::Left, &()) {
5581            let start = cursor.start().1.clone();
5582            let end = cursor.end(&()).1;
5583            let mut diff_transforms = self
5584                .diff_transforms
5585                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5586            diff_transforms.seek(&start, Bias::Left, &());
5587            let overshoot = start.0 - diff_transforms.start().0 .0;
5588            let start = diff_transforms.start().1 .0 + overshoot;
5589            diff_transforms.seek(&end, Bias::Right, &());
5590            let overshoot = end.0 - diff_transforms.start().0 .0;
5591            let end = diff_transforms.start().1 .0 + overshoot;
5592            Some(start..end)
5593        } else {
5594            None
5595        }
5596    }
5597
5598    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5599        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5600        let locator = self.excerpt_locator_for_id(excerpt_id);
5601        if cursor.seek(&Some(locator), Bias::Left, &()) {
5602            if let Some(excerpt) = cursor.item() {
5603                return Some(excerpt.range.context.clone());
5604            }
5605        }
5606        None
5607    }
5608
5609    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5610        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5611        let locator = self.excerpt_locator_for_id(excerpt_id);
5612        cursor.seek(&Some(locator), Bias::Left, &());
5613        if let Some(excerpt) = cursor.item() {
5614            if excerpt.id == excerpt_id {
5615                return Some(excerpt);
5616            }
5617        }
5618        None
5619    }
5620
5621    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5622    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5623        let range = range.start.to_offset(self)..range.end.to_offset(self);
5624        let mut cursor = self.cursor::<usize>();
5625        cursor.seek(&range.start);
5626
5627        let start_excerpt = cursor.excerpt()?;
5628        if range.end != range.start {
5629            cursor.seek_forward(&range.end);
5630            if cursor.excerpt()?.id != start_excerpt.id {
5631                return None;
5632            }
5633        }
5634
5635        cursor.seek_to_start_of_current_excerpt();
5636        let region = cursor.region()?;
5637        let offset = region.range.start;
5638        let buffer_offset = region.buffer_range.start;
5639        let excerpt_offset = cursor.excerpts.start().clone();
5640        Some(MultiBufferExcerpt {
5641            diff_transforms: cursor.diff_transforms,
5642            excerpt: start_excerpt,
5643            offset,
5644            buffer_offset,
5645            excerpt_offset,
5646        })
5647    }
5648
5649    pub fn selections_in_range<'a>(
5650        &'a self,
5651        range: &'a Range<Anchor>,
5652        include_local: bool,
5653    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5654        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5655        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5656        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5657        cursor.seek(start_locator, Bias::Left, &());
5658        cursor
5659            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5660            .flat_map(move |excerpt| {
5661                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5662                if excerpt.id == range.start.excerpt_id {
5663                    query_range.start = range.start.text_anchor;
5664                }
5665                if excerpt.id == range.end.excerpt_id {
5666                    query_range.end = range.end.text_anchor;
5667                }
5668
5669                excerpt
5670                    .buffer
5671                    .selections_in_range(query_range, include_local)
5672                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5673                        selections.map(move |selection| {
5674                            let mut start = Anchor {
5675                                buffer_id: Some(excerpt.buffer_id),
5676                                excerpt_id: excerpt.id,
5677                                text_anchor: selection.start,
5678                                diff_base_anchor: None,
5679                            };
5680                            let mut end = Anchor {
5681                                buffer_id: Some(excerpt.buffer_id),
5682                                excerpt_id: excerpt.id,
5683                                text_anchor: selection.end,
5684                                diff_base_anchor: None,
5685                            };
5686                            if range.start.cmp(&start, self).is_gt() {
5687                                start = range.start;
5688                            }
5689                            if range.end.cmp(&end, self).is_lt() {
5690                                end = range.end;
5691                            }
5692
5693                            (
5694                                replica_id,
5695                                line_mode,
5696                                cursor_shape,
5697                                Selection {
5698                                    id: selection.id,
5699                                    start,
5700                                    end,
5701                                    reversed: selection.reversed,
5702                                    goal: selection.goal,
5703                                },
5704                            )
5705                        })
5706                    })
5707            })
5708    }
5709
5710    pub fn show_headers(&self) -> bool {
5711        self.show_headers
5712    }
5713}
5714
5715#[cfg(any(test, feature = "test-support"))]
5716impl MultiBufferSnapshot {
5717    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5718        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5719        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5720        start..end
5721    }
5722
5723    #[cfg(any(test, feature = "test-support"))]
5724    fn check_invariants(&self) {
5725        let excerpts = self.excerpts.items(&());
5726        let excerpt_ids = self.excerpt_ids.items(&());
5727
5728        for (ix, excerpt) in excerpts.iter().enumerate() {
5729            if ix == 0 {
5730                if excerpt.locator <= Locator::min() {
5731                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5732                }
5733            } else if excerpt.locator <= excerpts[ix - 1].locator {
5734                panic!("excerpts are out-of-order: {:?}", excerpts);
5735            }
5736        }
5737
5738        for (ix, entry) in excerpt_ids.iter().enumerate() {
5739            if ix == 0 {
5740                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5741                    panic!("invalid first excerpt id {:?}", entry.id);
5742                }
5743            } else if entry.id <= excerpt_ids[ix - 1].id {
5744                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5745            }
5746        }
5747
5748        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5749            panic!(
5750                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5751                self.excerpts.summary().text.len,
5752                self.diff_transforms.summary().input,
5753                self.diff_transforms.items(&()),
5754            );
5755        }
5756
5757        let mut prev_transform: Option<&DiffTransform> = None;
5758        for item in self.diff_transforms.iter() {
5759            if let DiffTransform::BufferContent {
5760                summary,
5761                inserted_hunk_anchor,
5762            } = item
5763            {
5764                if let Some(DiffTransform::BufferContent {
5765                    inserted_hunk_anchor: prev_inserted_hunk_anchor,
5766                    ..
5767                }) = prev_transform
5768                {
5769                    if *inserted_hunk_anchor == *prev_inserted_hunk_anchor {
5770                        panic!(
5771                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_anchor:?}. transforms: {:+?}",
5772                            self.diff_transforms.items(&()));
5773                    }
5774                }
5775                if summary.len == 0 && !self.is_empty() {
5776                    panic!("empty buffer content transform");
5777                }
5778            }
5779            prev_transform = Some(item);
5780        }
5781    }
5782}
5783
5784impl<'a, D> MultiBufferCursor<'a, D>
5785where
5786    D: TextDimension + Ord + Sub<D, Output = D>,
5787{
5788    fn seek(&mut self, position: &D) {
5789        self.cached_region.take();
5790        self.diff_transforms
5791            .seek(&OutputDimension(*position), Bias::Right, &());
5792        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5793            self.diff_transforms.prev(&());
5794        }
5795
5796        let mut excerpt_position = self.diff_transforms.start().1 .0;
5797        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5798            let overshoot = *position - self.diff_transforms.start().0 .0;
5799            excerpt_position.add_assign(&overshoot);
5800        }
5801
5802        self.excerpts
5803            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
5804        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5805            self.excerpts.prev(&());
5806        }
5807    }
5808
5809    fn seek_forward(&mut self, position: &D) {
5810        self.cached_region.take();
5811        self.diff_transforms
5812            .seek_forward(&OutputDimension(*position), Bias::Right, &());
5813        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5814            self.diff_transforms.prev(&());
5815        }
5816
5817        let overshoot = *position - self.diff_transforms.start().0 .0;
5818        let mut excerpt_position = self.diff_transforms.start().1 .0;
5819        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5820            excerpt_position.add_assign(&overshoot);
5821        }
5822
5823        self.excerpts
5824            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
5825        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5826            self.excerpts.prev(&());
5827        }
5828    }
5829
5830    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
5831        self.cached_region.take();
5832        if let Some(excerpt) = self.excerpts.item() {
5833            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
5834            let position_in_excerpt = *position - excerpt_start;
5835            let mut excerpt_position = self.excerpts.start().0;
5836            excerpt_position.add_assign(&position_in_excerpt);
5837            self.diff_transforms
5838                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
5839            if self.diff_transforms.item().is_none() {
5840                self.diff_transforms.next(&());
5841            }
5842        }
5843    }
5844
5845    fn next_excerpt(&mut self) {
5846        self.excerpts.next(&());
5847        self.seek_to_start_of_current_excerpt();
5848    }
5849
5850    fn prev_excerpt(&mut self) {
5851        self.excerpts.prev(&());
5852        self.seek_to_start_of_current_excerpt();
5853    }
5854
5855    fn seek_to_start_of_current_excerpt(&mut self) {
5856        self.cached_region.take();
5857        self.diff_transforms
5858            .seek(self.excerpts.start(), Bias::Left, &());
5859        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
5860            && self.diff_transforms.start().1 < *self.excerpts.start()
5861            && self.diff_transforms.next_item().is_some()
5862        {
5863            self.diff_transforms.next(&());
5864        }
5865    }
5866
5867    fn next(&mut self) {
5868        self.cached_region.take();
5869        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
5870            cmp::Ordering::Less => self.diff_transforms.next(&()),
5871            cmp::Ordering::Greater => self.excerpts.next(&()),
5872            cmp::Ordering::Equal => {
5873                self.diff_transforms.next(&());
5874                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
5875                    || self.diff_transforms.item().is_none()
5876                {
5877                    self.excerpts.next(&());
5878                }
5879            }
5880        }
5881    }
5882
5883    fn prev(&mut self) {
5884        self.cached_region.take();
5885        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
5886            cmp::Ordering::Less => self.excerpts.prev(&()),
5887            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
5888            cmp::Ordering::Equal => {
5889                self.diff_transforms.prev(&());
5890                if self.diff_transforms.start().1 < *self.excerpts.start()
5891                    || self.diff_transforms.item().is_none()
5892                {
5893                    self.excerpts.prev(&());
5894                }
5895            }
5896        }
5897    }
5898
5899    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
5900        if self.cached_region.is_none() {
5901            self.cached_region = self.build_region();
5902        }
5903        self.cached_region.clone()
5904    }
5905
5906    fn main_buffer_position(&self) -> Option<D> {
5907        if let DiffTransform::BufferContent { .. } = self.diff_transforms.next_item()? {
5908            let excerpt = self.excerpts.item()?;
5909            let buffer = &excerpt.buffer;
5910            let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5911            let mut buffer_start = buffer_context_start;
5912            let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
5913            buffer_start.add_assign(&overshoot);
5914            Some(buffer_start)
5915        } else {
5916            None
5917        }
5918    }
5919
5920    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
5921        let excerpt = self.excerpts.item()?;
5922        match self.diff_transforms.item()? {
5923            DiffTransform::DeletedHunk {
5924                buffer_id,
5925                base_text_byte_range,
5926                has_trailing_newline,
5927                ..
5928            } => {
5929                let diff = self.diffs.get(&buffer_id)?;
5930                let buffer = &diff.base_text;
5931                let mut rope_cursor = buffer.as_rope().cursor(0);
5932                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
5933                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
5934                let mut buffer_end = buffer_start;
5935                buffer_end.add_assign(&buffer_range_len);
5936                let start = self.diff_transforms.start().0 .0;
5937                let end = self.diff_transforms.end(&()).0 .0;
5938                return Some(MultiBufferRegion {
5939                    buffer,
5940                    excerpt,
5941                    has_trailing_newline: *has_trailing_newline,
5942                    is_main_buffer: false,
5943                    is_inserted_hunk: false,
5944                    buffer_range: buffer_start..buffer_end,
5945                    range: start..end,
5946                });
5947            }
5948            DiffTransform::BufferContent {
5949                inserted_hunk_anchor,
5950                ..
5951            } => {
5952                let buffer = &excerpt.buffer;
5953                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5954
5955                let mut start = self.diff_transforms.start().0 .0;
5956                let mut buffer_start = buffer_context_start;
5957                if self.diff_transforms.start().1 < *self.excerpts.start() {
5958                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
5959                    start.add_assign(&overshoot);
5960                } else {
5961                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
5962                    buffer_start.add_assign(&overshoot);
5963                }
5964
5965                let mut end;
5966                let mut buffer_end;
5967                let has_trailing_newline;
5968                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
5969                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
5970                    end = self.diff_transforms.end(&()).0 .0;
5971                    buffer_end = buffer_context_start;
5972                    buffer_end.add_assign(&overshoot);
5973                    has_trailing_newline = false;
5974                } else {
5975                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
5976                    end = self.diff_transforms.start().0 .0;
5977                    end.add_assign(&overshoot);
5978                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
5979                    has_trailing_newline = excerpt.has_trailing_newline;
5980                };
5981
5982                Some(MultiBufferRegion {
5983                    buffer,
5984                    excerpt,
5985                    has_trailing_newline,
5986                    is_main_buffer: true,
5987                    is_inserted_hunk: inserted_hunk_anchor.is_some(),
5988                    buffer_range: buffer_start..buffer_end,
5989                    range: start..end,
5990                })
5991            }
5992        }
5993    }
5994
5995    fn excerpt(&self) -> Option<&'a Excerpt> {
5996        self.excerpts.item()
5997    }
5998}
5999
6000impl History {
6001    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6002        self.transaction_depth += 1;
6003        if self.transaction_depth == 1 {
6004            let id = self.next_transaction_id.tick();
6005            self.undo_stack.push(Transaction {
6006                id,
6007                buffer_transactions: Default::default(),
6008                first_edit_at: now,
6009                last_edit_at: now,
6010                suppress_grouping: false,
6011            });
6012            Some(id)
6013        } else {
6014            None
6015        }
6016    }
6017
6018    fn end_transaction(
6019        &mut self,
6020        now: Instant,
6021        buffer_transactions: HashMap<BufferId, TransactionId>,
6022    ) -> bool {
6023        assert_ne!(self.transaction_depth, 0);
6024        self.transaction_depth -= 1;
6025        if self.transaction_depth == 0 {
6026            if buffer_transactions.is_empty() {
6027                self.undo_stack.pop();
6028                false
6029            } else {
6030                self.redo_stack.clear();
6031                let transaction = self.undo_stack.last_mut().unwrap();
6032                transaction.last_edit_at = now;
6033                for (buffer_id, transaction_id) in buffer_transactions {
6034                    transaction
6035                        .buffer_transactions
6036                        .entry(buffer_id)
6037                        .or_insert(transaction_id);
6038                }
6039                true
6040            }
6041        } else {
6042            false
6043        }
6044    }
6045
6046    fn push_transaction<'a, T>(
6047        &mut self,
6048        buffer_transactions: T,
6049        now: Instant,
6050        cx: &Context<MultiBuffer>,
6051    ) where
6052        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6053    {
6054        assert_eq!(self.transaction_depth, 0);
6055        let transaction = Transaction {
6056            id: self.next_transaction_id.tick(),
6057            buffer_transactions: buffer_transactions
6058                .into_iter()
6059                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6060                .collect(),
6061            first_edit_at: now,
6062            last_edit_at: now,
6063            suppress_grouping: false,
6064        };
6065        if !transaction.buffer_transactions.is_empty() {
6066            self.undo_stack.push(transaction);
6067            self.redo_stack.clear();
6068        }
6069    }
6070
6071    fn finalize_last_transaction(&mut self) {
6072        if let Some(transaction) = self.undo_stack.last_mut() {
6073            transaction.suppress_grouping = true;
6074        }
6075    }
6076
6077    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6078        if let Some(ix) = self
6079            .undo_stack
6080            .iter()
6081            .rposition(|transaction| transaction.id == transaction_id)
6082        {
6083            Some(self.undo_stack.remove(ix))
6084        } else if let Some(ix) = self
6085            .redo_stack
6086            .iter()
6087            .rposition(|transaction| transaction.id == transaction_id)
6088        {
6089            Some(self.redo_stack.remove(ix))
6090        } else {
6091            None
6092        }
6093    }
6094
6095    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6096        self.undo_stack
6097            .iter()
6098            .find(|transaction| transaction.id == transaction_id)
6099            .or_else(|| {
6100                self.redo_stack
6101                    .iter()
6102                    .find(|transaction| transaction.id == transaction_id)
6103            })
6104    }
6105
6106    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6107        self.undo_stack
6108            .iter_mut()
6109            .find(|transaction| transaction.id == transaction_id)
6110            .or_else(|| {
6111                self.redo_stack
6112                    .iter_mut()
6113                    .find(|transaction| transaction.id == transaction_id)
6114            })
6115    }
6116
6117    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6118        assert_eq!(self.transaction_depth, 0);
6119        if let Some(transaction) = self.undo_stack.pop() {
6120            self.redo_stack.push(transaction);
6121            self.redo_stack.last_mut()
6122        } else {
6123            None
6124        }
6125    }
6126
6127    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6128        assert_eq!(self.transaction_depth, 0);
6129        if let Some(transaction) = self.redo_stack.pop() {
6130            self.undo_stack.push(transaction);
6131            self.undo_stack.last_mut()
6132        } else {
6133            None
6134        }
6135    }
6136
6137    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6138        let ix = self
6139            .undo_stack
6140            .iter()
6141            .rposition(|transaction| transaction.id == transaction_id)?;
6142        let transaction = self.undo_stack.remove(ix);
6143        self.redo_stack.push(transaction);
6144        self.redo_stack.last()
6145    }
6146
6147    fn group(&mut self) -> Option<TransactionId> {
6148        let mut count = 0;
6149        let mut transactions = self.undo_stack.iter();
6150        if let Some(mut transaction) = transactions.next_back() {
6151            while let Some(prev_transaction) = transactions.next_back() {
6152                if !prev_transaction.suppress_grouping
6153                    && transaction.first_edit_at - prev_transaction.last_edit_at
6154                        <= self.group_interval
6155                {
6156                    transaction = prev_transaction;
6157                    count += 1;
6158                } else {
6159                    break;
6160                }
6161            }
6162        }
6163        self.group_trailing(count)
6164    }
6165
6166    fn group_until(&mut self, transaction_id: TransactionId) {
6167        let mut count = 0;
6168        for transaction in self.undo_stack.iter().rev() {
6169            if transaction.id == transaction_id {
6170                self.group_trailing(count);
6171                break;
6172            } else if transaction.suppress_grouping {
6173                break;
6174            } else {
6175                count += 1;
6176            }
6177        }
6178    }
6179
6180    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6181        let new_len = self.undo_stack.len() - n;
6182        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6183        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6184            if let Some(transaction) = transactions_to_merge.last() {
6185                last_transaction.last_edit_at = transaction.last_edit_at;
6186            }
6187            for to_merge in transactions_to_merge {
6188                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6189                    last_transaction
6190                        .buffer_transactions
6191                        .entry(*buffer_id)
6192                        .or_insert(*transaction_id);
6193                }
6194            }
6195        }
6196
6197        self.undo_stack.truncate(new_len);
6198        self.undo_stack.last().map(|t| t.id)
6199    }
6200}
6201
6202impl Excerpt {
6203    fn new(
6204        id: ExcerptId,
6205        locator: Locator,
6206        buffer_id: BufferId,
6207        buffer: BufferSnapshot,
6208        range: ExcerptRange<text::Anchor>,
6209        has_trailing_newline: bool,
6210    ) -> Self {
6211        Excerpt {
6212            id,
6213            locator,
6214            max_buffer_row: range.context.end.to_point(&buffer).row,
6215            text_summary: buffer
6216                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6217            buffer_id,
6218            buffer,
6219            range,
6220            has_trailing_newline,
6221        }
6222    }
6223
6224    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6225        let content_start = self.range.context.start.to_offset(&self.buffer);
6226        let chunks_start = content_start + range.start;
6227        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6228
6229        let footer_height = if self.has_trailing_newline
6230            && range.start <= self.text_summary.len
6231            && range.end > self.text_summary.len
6232        {
6233            1
6234        } else {
6235            0
6236        };
6237
6238        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6239
6240        ExcerptChunks {
6241            excerpt_id: self.id,
6242            content_chunks,
6243            footer_height,
6244        }
6245    }
6246
6247    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6248        let content_start = self.range.context.start.to_offset(&self.buffer);
6249        let chunks_start = content_start + range.start;
6250        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6251        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6252        excerpt_chunks.footer_height = if self.has_trailing_newline
6253            && range.start <= self.text_summary.len
6254            && range.end > self.text_summary.len
6255        {
6256            1
6257        } else {
6258            0
6259        };
6260    }
6261
6262    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6263        if text_anchor
6264            .cmp(&self.range.context.start, &self.buffer)
6265            .is_lt()
6266        {
6267            self.range.context.start
6268        } else if text_anchor
6269            .cmp(&self.range.context.end, &self.buffer)
6270            .is_gt()
6271        {
6272            self.range.context.end
6273        } else {
6274            text_anchor
6275        }
6276    }
6277
6278    fn contains(&self, anchor: &Anchor) -> bool {
6279        Some(self.buffer_id) == anchor.buffer_id
6280            && self
6281                .range
6282                .context
6283                .start
6284                .cmp(&anchor.text_anchor, &self.buffer)
6285                .is_le()
6286            && self
6287                .range
6288                .context
6289                .end
6290                .cmp(&anchor.text_anchor, &self.buffer)
6291                .is_ge()
6292    }
6293
6294    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6295    fn buffer_start_offset(&self) -> usize {
6296        self.range.context.start.to_offset(&self.buffer)
6297    }
6298
6299    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6300    fn buffer_end_offset(&self) -> usize {
6301        self.buffer_start_offset() + self.text_summary.len
6302    }
6303}
6304
6305impl<'a> MultiBufferExcerpt<'a> {
6306    pub fn id(&self) -> ExcerptId {
6307        self.excerpt.id
6308    }
6309
6310    pub fn buffer_id(&self) -> BufferId {
6311        self.excerpt.buffer_id
6312    }
6313
6314    pub fn start_anchor(&self) -> Anchor {
6315        Anchor {
6316            buffer_id: Some(self.excerpt.buffer_id),
6317            excerpt_id: self.excerpt.id,
6318            text_anchor: self.excerpt.range.context.start,
6319            diff_base_anchor: None,
6320        }
6321    }
6322
6323    pub fn end_anchor(&self) -> Anchor {
6324        Anchor {
6325            buffer_id: Some(self.excerpt.buffer_id),
6326            excerpt_id: self.excerpt.id,
6327            text_anchor: self.excerpt.range.context.end,
6328            diff_base_anchor: None,
6329        }
6330    }
6331
6332    pub fn buffer(&self) -> &'a BufferSnapshot {
6333        &self.excerpt.buffer
6334    }
6335
6336    pub fn buffer_range(&self) -> Range<usize> {
6337        self.buffer_offset
6338            ..self
6339                .excerpt
6340                .range
6341                .context
6342                .end
6343                .to_offset(&self.excerpt.buffer.text)
6344    }
6345
6346    pub fn start_offset(&self) -> usize {
6347        self.offset
6348    }
6349
6350    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6351    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6352        self.map_range_to_buffer(offset..offset).start
6353    }
6354
6355    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6356    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6357        self.diff_transforms
6358            .seek(&OutputDimension(range.start), Bias::Right, &());
6359        let start = self.map_offset_to_buffer_internal(range.start);
6360        let end = if range.end > range.start {
6361            self.diff_transforms
6362                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6363            self.map_offset_to_buffer_internal(range.end)
6364        } else {
6365            start
6366        };
6367        start..end
6368    }
6369
6370    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6371        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6372        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6373            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6374        };
6375        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6376        self.buffer_offset + offset_in_excerpt
6377    }
6378
6379    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6380    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6381        self.map_range_from_buffer(buffer_offset..buffer_offset)
6382            .start
6383    }
6384
6385    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6386    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6387        let overshoot = buffer_range.start - self.buffer_offset;
6388        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6389        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6390        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6391        let start = self.diff_transforms.start().0 .0 + overshoot;
6392
6393        let end = if buffer_range.end > buffer_range.start {
6394            let overshoot = buffer_range.end - self.buffer_offset;
6395            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6396            self.diff_transforms
6397                .seek_forward(&excerpt_offset, Bias::Right, &());
6398            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6399            self.diff_transforms.start().0 .0 + overshoot
6400        } else {
6401            start
6402        };
6403
6404        start..end
6405    }
6406
6407    /// Returns true if the entirety of the given range is in the buffer's excerpt
6408    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6409        range.start >= self.excerpt.buffer_start_offset()
6410            && range.end <= self.excerpt.buffer_end_offset()
6411    }
6412
6413    pub fn max_buffer_row(&self) -> u32 {
6414        self.excerpt.max_buffer_row
6415    }
6416}
6417
6418impl ExcerptId {
6419    pub fn min() -> Self {
6420        Self(0)
6421    }
6422
6423    pub fn max() -> Self {
6424        Self(usize::MAX)
6425    }
6426
6427    pub fn to_proto(&self) -> u64 {
6428        self.0 as _
6429    }
6430
6431    pub fn from_proto(proto: u64) -> Self {
6432        Self(proto as _)
6433    }
6434
6435    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6436        let a = snapshot.excerpt_locator_for_id(*self);
6437        let b = snapshot.excerpt_locator_for_id(*other);
6438        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6439    }
6440}
6441
6442impl From<ExcerptId> for usize {
6443    fn from(val: ExcerptId) -> Self {
6444        val.0
6445    }
6446}
6447
6448impl fmt::Debug for Excerpt {
6449    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6450        f.debug_struct("Excerpt")
6451            .field("id", &self.id)
6452            .field("locator", &self.locator)
6453            .field("buffer_id", &self.buffer_id)
6454            .field("range", &self.range)
6455            .field("text_summary", &self.text_summary)
6456            .field("has_trailing_newline", &self.has_trailing_newline)
6457            .finish()
6458    }
6459}
6460
6461impl sum_tree::Item for Excerpt {
6462    type Summary = ExcerptSummary;
6463
6464    fn summary(&self, _cx: &()) -> Self::Summary {
6465        let mut text = self.text_summary;
6466        if self.has_trailing_newline {
6467            text += TextSummary::from("\n");
6468        }
6469        ExcerptSummary {
6470            excerpt_id: self.id,
6471            excerpt_locator: self.locator.clone(),
6472            widest_line_number: self.max_buffer_row,
6473            text,
6474        }
6475    }
6476}
6477
6478impl sum_tree::Item for ExcerptIdMapping {
6479    type Summary = ExcerptId;
6480
6481    fn summary(&self, _cx: &()) -> Self::Summary {
6482        self.id
6483    }
6484}
6485
6486impl sum_tree::KeyedItem for ExcerptIdMapping {
6487    type Key = ExcerptId;
6488
6489    fn key(&self) -> Self::Key {
6490        self.id
6491    }
6492}
6493
6494impl DiffTransform {
6495    fn hunk_anchor(&self) -> Option<(ExcerptId, text::Anchor)> {
6496        match self {
6497            DiffTransform::DeletedHunk { hunk_anchor, .. } => Some(*hunk_anchor),
6498            DiffTransform::BufferContent {
6499                inserted_hunk_anchor,
6500                ..
6501            } => *inserted_hunk_anchor,
6502        }
6503    }
6504}
6505
6506impl sum_tree::Item for DiffTransform {
6507    type Summary = DiffTransformSummary;
6508
6509    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6510        match self {
6511            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6512                input: *summary,
6513                output: *summary,
6514            },
6515            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6516                input: TextSummary::default(),
6517                output: *summary,
6518            },
6519        }
6520    }
6521}
6522
6523impl DiffTransformSummary {
6524    fn excerpt_len(&self) -> ExcerptOffset {
6525        ExcerptOffset::new(self.input.len)
6526    }
6527}
6528
6529impl sum_tree::Summary for DiffTransformSummary {
6530    type Context = ();
6531
6532    fn zero(_: &Self::Context) -> Self {
6533        DiffTransformSummary {
6534            input: TextSummary::default(),
6535            output: TextSummary::default(),
6536        }
6537    }
6538
6539    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6540        self.input += &summary.input;
6541        self.output += &summary.output;
6542    }
6543}
6544
6545impl sum_tree::Summary for ExcerptId {
6546    type Context = ();
6547
6548    fn zero(_cx: &()) -> Self {
6549        Default::default()
6550    }
6551
6552    fn add_summary(&mut self, other: &Self, _: &()) {
6553        *self = *other;
6554    }
6555}
6556
6557impl sum_tree::Summary for ExcerptSummary {
6558    type Context = ();
6559
6560    fn zero(_cx: &()) -> Self {
6561        Default::default()
6562    }
6563
6564    fn add_summary(&mut self, summary: &Self, _: &()) {
6565        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6566        self.excerpt_locator = summary.excerpt_locator.clone();
6567        self.text.add_summary(&summary.text, &());
6568        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6569    }
6570}
6571
6572impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6573    fn zero(_cx: &()) -> Self {
6574        Default::default()
6575    }
6576
6577    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6578        self.value += summary.text.len;
6579    }
6580}
6581
6582impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6583    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6584        Ord::cmp(&self.value, &cursor_location.text.len)
6585    }
6586}
6587
6588impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6589    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6590        Ord::cmp(&Some(self), cursor_location)
6591    }
6592}
6593
6594impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
6595    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6596        Ord::cmp(self, &cursor_location.excerpt_locator)
6597    }
6598}
6599
6600impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6601    fn zero(_cx: &()) -> Self {
6602        Default::default()
6603    }
6604
6605    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6606        self.value += summary.text.lines;
6607    }
6608}
6609
6610impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6611    for ExcerptDimension<D>
6612{
6613    fn zero(_: &()) -> Self {
6614        ExcerptDimension(D::default())
6615    }
6616
6617    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6618        self.0.add_assign(&D::from_text_summary(&summary.text))
6619    }
6620}
6621
6622impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6623    fn zero(_cx: &()) -> Self {
6624        Default::default()
6625    }
6626
6627    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6628        *self = Some(&summary.excerpt_locator);
6629    }
6630}
6631
6632impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6633    fn zero(_cx: &()) -> Self {
6634        Default::default()
6635    }
6636
6637    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6638        *self = Some(summary.excerpt_id);
6639    }
6640}
6641
6642#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6643struct ExcerptDimension<T>(T);
6644
6645#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6646struct OutputDimension<T>(T);
6647
6648impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6649    fn zero(_: &()) -> Self {
6650        ExcerptOffset::new(0)
6651    }
6652
6653    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6654        self.value += summary.input.len;
6655    }
6656}
6657
6658impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6659    fn zero(_: &()) -> Self {
6660        ExcerptPoint::new(0, 0)
6661    }
6662
6663    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6664        self.value += summary.input.lines;
6665    }
6666}
6667
6668impl<'a, D: TextDimension + Ord>
6669    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransformSummary> for ExcerptDimension<D>
6670{
6671    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6672        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6673    }
6674}
6675
6676impl<'a, D: TextDimension + Ord>
6677    sum_tree::SeekTarget<'a, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6678    for ExcerptDimension<D>
6679{
6680    fn cmp(
6681        &self,
6682        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6683        _: &(),
6684    ) -> cmp::Ordering {
6685        Ord::cmp(&self.0, &cursor_location.1 .0)
6686    }
6687}
6688
6689impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6690    fn zero(_: &()) -> Self {
6691        ExcerptDimension(D::default())
6692    }
6693
6694    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6695        self.0.add_assign(&D::from_text_summary(&summary.input))
6696    }
6697}
6698
6699impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6700    fn zero(_: &()) -> Self {
6701        OutputDimension(D::default())
6702    }
6703
6704    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6705        self.0.add_assign(&D::from_text_summary(&summary.output))
6706    }
6707}
6708
6709impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6710    fn zero(_: &()) -> Self {
6711        TextSummary::default()
6712    }
6713
6714    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6715        *self += summary.output
6716    }
6717}
6718
6719impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6720    fn zero(_: &()) -> Self {
6721        0
6722    }
6723
6724    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6725        *self += summary.output.len
6726    }
6727}
6728
6729impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6730    fn zero(_: &()) -> Self {
6731        Point::new(0, 0)
6732    }
6733
6734    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6735        *self += summary.output.lines
6736    }
6737}
6738
6739impl<'a> MultiBufferRows<'a> {
6740    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6741        self.point = Point::new(row, 0);
6742        self.cursor.seek(&self.point);
6743    }
6744}
6745
6746impl<'a> Iterator for MultiBufferRows<'a> {
6747    type Item = RowInfo;
6748
6749    fn next(&mut self) -> Option<Self::Item> {
6750        if self.is_empty && self.point.row == 0 {
6751            self.point += Point::new(1, 0);
6752            return Some(RowInfo {
6753                buffer_row: Some(0),
6754                multibuffer_row: Some(MultiBufferRow(0)),
6755                diff_status: None,
6756            });
6757        }
6758
6759        let mut region = self.cursor.region()?;
6760        while self.point >= region.range.end {
6761            self.cursor.next();
6762            if let Some(next_region) = self.cursor.region() {
6763                region = next_region;
6764            } else {
6765                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
6766                    let multibuffer_row = MultiBufferRow(self.point.row);
6767                    self.point += Point::new(1, 0);
6768                    let last_excerpt = self
6769                        .cursor
6770                        .excerpts
6771                        .item()
6772                        .or(self.cursor.excerpts.prev_item())?;
6773                    let last_row = last_excerpt
6774                        .range
6775                        .context
6776                        .end
6777                        .to_point(&last_excerpt.buffer)
6778                        .row;
6779                    return Some(RowInfo {
6780                        buffer_row: Some(last_row),
6781                        multibuffer_row: Some(multibuffer_row),
6782                        diff_status: None,
6783                    });
6784                } else {
6785                    return None;
6786                }
6787            };
6788        }
6789
6790        let overshoot = self.point - region.range.start;
6791        let buffer_point = region.buffer_range.start + overshoot;
6792        let result = Some(RowInfo {
6793            buffer_row: Some(buffer_point.row),
6794            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6795            diff_status: if region.is_inserted_hunk && self.point < region.range.end {
6796                Some(DiffHunkStatus::Added)
6797            } else if !region.is_main_buffer {
6798                Some(DiffHunkStatus::Removed)
6799            } else {
6800                None
6801            },
6802        });
6803        self.point += Point::new(1, 0);
6804        result
6805    }
6806}
6807
6808impl<'a> MultiBufferChunks<'a> {
6809    pub fn offset(&self) -> usize {
6810        self.range.start
6811    }
6812
6813    pub fn seek(&mut self, range: Range<usize>) {
6814        self.diff_transforms.seek(&range.end, Bias::Right, &());
6815        let mut excerpt_end = self.diff_transforms.start().1;
6816        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6817            let overshoot = range.end - self.diff_transforms.start().0;
6818            excerpt_end.value += overshoot;
6819        }
6820
6821        self.diff_transforms.seek(&range.start, Bias::Right, &());
6822        let mut excerpt_start = self.diff_transforms.start().1;
6823        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6824            let overshoot = range.start - self.diff_transforms.start().0;
6825            excerpt_start.value += overshoot;
6826        }
6827
6828        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6829        self.buffer_chunk.take();
6830        self.range = range;
6831    }
6832
6833    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6834        self.excerpt_offset_range = new_range.clone();
6835        self.excerpts.seek(&new_range.start, Bias::Right, &());
6836        if let Some(excerpt) = self.excerpts.item() {
6837            let excerpt_start = *self.excerpts.start();
6838            if let Some(excerpt_chunks) = self
6839                .excerpt_chunks
6840                .as_mut()
6841                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6842            {
6843                excerpt.seek_chunks(
6844                    excerpt_chunks,
6845                    (self.excerpt_offset_range.start - excerpt_start).value
6846                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6847                );
6848            } else {
6849                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6850                    (self.excerpt_offset_range.start - excerpt_start).value
6851                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6852                    self.language_aware,
6853                ));
6854            }
6855        } else {
6856            self.excerpt_chunks = None;
6857        }
6858    }
6859
6860    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6861        loop {
6862            if self.excerpt_offset_range.is_empty() {
6863                return None;
6864            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6865                self.excerpt_offset_range.start.value += chunk.text.len();
6866                return Some(chunk);
6867            } else {
6868                self.excerpts.next(&());
6869                let excerpt = self.excerpts.item()?;
6870                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6871                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6872                    self.language_aware,
6873                ));
6874            }
6875        }
6876    }
6877}
6878
6879impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6880    type Item = &'a str;
6881
6882    fn next(&mut self) -> Option<Self::Item> {
6883        let mut region = self.cursor.region()?;
6884        if self.offset == region.range.start {
6885            self.cursor.prev();
6886            region = self.cursor.region()?;
6887            let start_overshoot = self.start.saturating_sub(region.range.start);
6888            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6889                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6890            ));
6891        }
6892
6893        if self.offset == region.range.end && region.has_trailing_newline {
6894            self.offset -= 1;
6895            Some("\n")
6896        } else {
6897            let chunk = self.current_chunks.as_mut().unwrap().next().unwrap();
6898            self.offset -= chunk.len();
6899            Some(chunk)
6900        }
6901    }
6902}
6903
6904impl<'a> Iterator for MultiBufferChunks<'a> {
6905    type Item = Chunk<'a>;
6906
6907    fn next(&mut self) -> Option<Chunk<'a>> {
6908        if self.range.start >= self.range.end {
6909            return None;
6910        }
6911        if self.range.start == self.diff_transforms.end(&()).0 {
6912            self.diff_transforms.next(&());
6913        }
6914
6915        let diff_transform_start = self.diff_transforms.start().0;
6916        let diff_transform_end = self.diff_transforms.end(&()).0;
6917        debug_assert!(self.range.start < diff_transform_end);
6918
6919        let diff_transform = self.diff_transforms.item()?;
6920        match diff_transform {
6921            DiffTransform::BufferContent { .. } => {
6922                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6923                    chunk
6924                } else {
6925                    let chunk = self.next_excerpt_chunk().unwrap();
6926                    self.buffer_chunk.insert(chunk)
6927                };
6928
6929                let chunk_end = self.range.start + chunk.text.len();
6930                let diff_transform_end = diff_transform_end.min(self.range.end);
6931
6932                if diff_transform_end < chunk_end {
6933                    let (before, after) =
6934                        chunk.text.split_at(diff_transform_end - self.range.start);
6935                    self.range.start = diff_transform_end;
6936                    chunk.text = after;
6937                    Some(Chunk {
6938                        text: before,
6939                        ..chunk.clone()
6940                    })
6941                } else {
6942                    self.range.start = chunk_end;
6943                    self.buffer_chunk.take()
6944                }
6945            }
6946            DiffTransform::DeletedHunk {
6947                buffer_id,
6948                base_text_byte_range,
6949                has_trailing_newline,
6950                ..
6951            } => {
6952                let base_text_start =
6953                    base_text_byte_range.start + self.range.start - diff_transform_start;
6954                let base_text_end =
6955                    base_text_byte_range.start + self.range.end - diff_transform_start;
6956                let base_text_end = base_text_end.min(base_text_byte_range.end);
6957
6958                let mut chunks = if let Some((_, mut chunks)) = self
6959                    .diff_base_chunks
6960                    .take()
6961                    .filter(|(id, _)| id == buffer_id)
6962                {
6963                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
6964                    {
6965                        chunks.seek(base_text_start..base_text_end);
6966                    }
6967                    chunks
6968                } else {
6969                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text;
6970                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
6971                };
6972
6973                let chunk = if let Some(chunk) = chunks.next() {
6974                    self.range.start += chunk.text.len();
6975                    self.diff_base_chunks = Some((*buffer_id, chunks));
6976                    chunk
6977                } else {
6978                    debug_assert!(has_trailing_newline);
6979                    self.range.start += "\n".len();
6980                    Chunk {
6981                        text: "\n",
6982                        ..Default::default()
6983                    }
6984                };
6985                Some(chunk)
6986            }
6987        }
6988    }
6989}
6990
6991impl<'a> MultiBufferBytes<'a> {
6992    fn consume(&mut self, len: usize) {
6993        self.range.start += len;
6994        self.chunk = &self.chunk[len..];
6995
6996        if !self.range.is_empty() && self.chunk.is_empty() {
6997            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
6998                self.chunk = chunk;
6999            } else if self.has_trailing_newline {
7000                self.has_trailing_newline = false;
7001                self.chunk = b"\n";
7002            } else {
7003                self.cursor.next();
7004                if let Some(region) = self.cursor.region() {
7005                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7006                        region.buffer_range.start
7007                            ..(region.buffer_range.start + self.range.end - region.range.start)
7008                                .min(region.buffer_range.end),
7009                    );
7010                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7011                    self.excerpt_bytes = Some(excerpt_bytes);
7012                    self.has_trailing_newline =
7013                        region.has_trailing_newline && self.range.end >= region.range.end;
7014                    if self.chunk.is_empty() && self.has_trailing_newline {
7015                        self.has_trailing_newline = false;
7016                        self.chunk = b"\n";
7017                    }
7018                }
7019            }
7020        }
7021    }
7022}
7023
7024impl<'a> Iterator for MultiBufferBytes<'a> {
7025    type Item = &'a [u8];
7026
7027    fn next(&mut self) -> Option<Self::Item> {
7028        let chunk = self.chunk;
7029        if chunk.is_empty() {
7030            None
7031        } else {
7032            self.consume(chunk.len());
7033            Some(chunk)
7034        }
7035    }
7036}
7037
7038impl<'a> io::Read for MultiBufferBytes<'a> {
7039    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7040        let len = cmp::min(buf.len(), self.chunk.len());
7041        buf[..len].copy_from_slice(&self.chunk[..len]);
7042        if len > 0 {
7043            self.consume(len);
7044        }
7045        Ok(len)
7046    }
7047}
7048
7049impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
7050    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7051        let len = cmp::min(buf.len(), self.chunk.len());
7052        buf[..len].copy_from_slice(&self.chunk[..len]);
7053        buf[..len].reverse();
7054        if len > 0 {
7055            self.range.end -= len;
7056            self.chunk = &self.chunk[..self.chunk.len() - len];
7057            if !self.range.is_empty() && self.chunk.is_empty() {
7058                if let Some(chunk) = self.chunks.next() {
7059                    self.chunk = chunk.as_bytes();
7060                }
7061            }
7062        }
7063        Ok(len)
7064    }
7065}
7066
7067impl<'a> Iterator for ExcerptChunks<'a> {
7068    type Item = Chunk<'a>;
7069
7070    fn next(&mut self) -> Option<Self::Item> {
7071        if let Some(chunk) = self.content_chunks.next() {
7072            return Some(chunk);
7073        }
7074
7075        if self.footer_height > 0 {
7076            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7077            self.footer_height = 0;
7078            return Some(Chunk {
7079                text,
7080                ..Default::default()
7081            });
7082        }
7083
7084        None
7085    }
7086}
7087
7088impl ToOffset for Point {
7089    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7090        snapshot.point_to_offset(*self)
7091    }
7092}
7093
7094impl ToOffset for usize {
7095    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7096        assert!(*self <= snapshot.len(), "offset is out of range");
7097        *self
7098    }
7099}
7100
7101impl ToOffset for OffsetUtf16 {
7102    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7103        snapshot.offset_utf16_to_offset(*self)
7104    }
7105}
7106
7107impl ToOffset for PointUtf16 {
7108    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7109        snapshot.point_utf16_to_offset(*self)
7110    }
7111}
7112
7113impl ToOffsetUtf16 for OffsetUtf16 {
7114    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7115        *self
7116    }
7117}
7118
7119impl ToOffsetUtf16 for usize {
7120    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7121        snapshot.offset_to_offset_utf16(*self)
7122    }
7123}
7124
7125impl ToPoint for usize {
7126    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7127        snapshot.offset_to_point(*self)
7128    }
7129}
7130
7131impl ToPoint for Point {
7132    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7133        *self
7134    }
7135}
7136
7137impl ToPointUtf16 for usize {
7138    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7139        snapshot.offset_to_point_utf16(*self)
7140    }
7141}
7142
7143impl ToPointUtf16 for Point {
7144    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7145        snapshot.point_to_point_utf16(*self)
7146    }
7147}
7148
7149impl ToPointUtf16 for PointUtf16 {
7150    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7151        *self
7152    }
7153}
7154
7155impl From<ExcerptId> for EntityId {
7156    fn from(id: ExcerptId) -> Self {
7157        EntityId::from(id.0 as u64)
7158    }
7159}
7160
7161pub fn build_excerpt_ranges<T>(
7162    buffer: &BufferSnapshot,
7163    ranges: &[Range<T>],
7164    context_line_count: u32,
7165) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7166where
7167    T: text::ToPoint,
7168{
7169    let max_point = buffer.max_point();
7170    let mut range_counts = Vec::new();
7171    let mut excerpt_ranges = Vec::new();
7172    let mut range_iter = ranges
7173        .iter()
7174        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7175        .peekable();
7176    while let Some(range) = range_iter.next() {
7177        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7178        let row = (range.end.row + context_line_count).min(max_point.row);
7179        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7180
7181        let mut ranges_in_excerpt = 1;
7182
7183        while let Some(next_range) = range_iter.peek() {
7184            if next_range.start.row <= excerpt_end.row + context_line_count {
7185                let row = (next_range.end.row + context_line_count).min(max_point.row);
7186                excerpt_end = Point::new(row, buffer.line_len(row));
7187
7188                ranges_in_excerpt += 1;
7189                range_iter.next();
7190            } else {
7191                break;
7192            }
7193        }
7194
7195        excerpt_ranges.push(ExcerptRange {
7196            context: excerpt_start..excerpt_end,
7197            primary: Some(range),
7198        });
7199        range_counts.push(ranges_in_excerpt);
7200    }
7201
7202    (excerpt_ranges, range_counts)
7203}