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                        .min(region.buffer_range.end.key)
3489                } else {
3490                    cursor.main_buffer_position()?.key
3491                };
3492                let mut buffer_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3493                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3494                    if excerpt.id == end_excerpt_id {
3495                        buffer_end = buffer_end.min(end_buffer_offset);
3496                    }
3497                }
3498
3499                if let Some(iterator) =
3500                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3501                {
3502                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3503                } else {
3504                    None
3505                }
3506            };
3507
3508            // Visit each metadata item.
3509            if let Some((range, metadata)) = metadata_iter.and_then(Iterator::next) {
3510                // Find the multibuffer regions that contain the start and end of
3511                // the metadata item's range.
3512                if range.start > D::default() {
3513                    while let Some(region) = cursor.region() {
3514                        if !region.is_main_buffer
3515                            || region.buffer.remote_id() == excerpt.buffer_id
3516                                && region.buffer_range.end.value.unwrap() < range.start
3517                        {
3518                            cursor.next();
3519                        } else {
3520                            break;
3521                        }
3522                    }
3523                }
3524                let start_region = cursor.region()?;
3525                while let Some(region) = cursor.region() {
3526                    if !region.is_main_buffer
3527                        || region.buffer.remote_id() == excerpt.buffer_id
3528                            && region.buffer_range.end.value.unwrap() <= range.end
3529                    {
3530                        cursor.next();
3531                    } else {
3532                        break;
3533                    }
3534                }
3535                let end_region = cursor
3536                    .region()
3537                    .filter(|region| region.buffer.remote_id() == excerpt.buffer_id);
3538
3539                // Convert the metadata item's range into multibuffer coordinates.
3540                let mut start = start_region.range.start.value.unwrap();
3541                let region_buffer_start = start_region.buffer_range.start.value.unwrap();
3542                if start_region.is_main_buffer && range.start > region_buffer_start {
3543                    start.add_assign(&(range.start - region_buffer_start));
3544                }
3545                let mut end = max_position;
3546                if let Some(end_region) = end_region {
3547                    end = end_region.range.start.value.unwrap();
3548                    debug_assert!(end_region.is_main_buffer);
3549                    let region_buffer_start = end_region.buffer_range.start.value.unwrap();
3550                    if range.end > region_buffer_start {
3551                        end.add_assign(&(range.end - region_buffer_start));
3552                    }
3553                }
3554
3555                return Some((start..end, metadata, excerpt));
3556            }
3557            // When there are no more metadata items for this excerpt, move to the next excerpt.
3558            else {
3559                current_excerpt_metadata.take();
3560                cursor.next_excerpt();
3561            }
3562        })
3563    }
3564
3565    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3566        let offset = position.to_offset(self);
3567
3568        // Go to the region containing the given offset.
3569        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3570        cursor.seek(&DimensionPair {
3571            key: offset,
3572            value: None,
3573        });
3574        let mut region = cursor.region()?;
3575        if region.range.start.key == offset || !region.is_main_buffer {
3576            cursor.prev();
3577            region = cursor.region()?;
3578        }
3579
3580        // Find the corresponding buffer offset.
3581        let overshoot = if region.is_main_buffer {
3582            offset - region.range.start.key
3583        } else {
3584            0
3585        };
3586        let mut max_buffer_offset = region
3587            .buffer
3588            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3589
3590        loop {
3591            let excerpt = cursor.excerpt()?;
3592            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3593            let buffer_offset = excerpt_end.min(max_buffer_offset);
3594            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3595            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3596
3597            if let Some(diff_state) = self.diffs.get(&excerpt.buffer_id) {
3598                for hunk in diff_state.diff.hunks_intersecting_range_rev(
3599                    excerpt.range.context.start..buffer_end,
3600                    &excerpt.buffer,
3601                ) {
3602                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3603                    if hunk.row_range.end >= buffer_end_row {
3604                        continue;
3605                    }
3606
3607                    let hunk_start = Point::new(hunk.row_range.start, 0);
3608                    let hunk_end = Point::new(hunk.row_range.end, 0);
3609
3610                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3611                        key: hunk_range.start,
3612                        value: None,
3613                    });
3614
3615                    let mut region = cursor.region()?;
3616                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3617                    {
3618                        cursor.prev();
3619                        region = cursor.region()?;
3620                    }
3621
3622                    let overshoot = if region.is_main_buffer {
3623                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3624                    } else {
3625                        Point::zero()
3626                    };
3627                    let start = region.range.start.value.unwrap() + overshoot;
3628
3629                    while let Some(region) = cursor.region() {
3630                        if !region.is_main_buffer
3631                            || region.buffer_range.end.value.unwrap() <= hunk_end
3632                        {
3633                            cursor.next();
3634                        } else {
3635                            break;
3636                        }
3637                    }
3638
3639                    let end = if let Some(region) = cursor.region() {
3640                        let overshoot = if region.is_main_buffer {
3641                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3642                        } else {
3643                            Point::zero()
3644                        };
3645                        region.range.start.value.unwrap() + overshoot
3646                    } else {
3647                        self.max_point()
3648                    };
3649
3650                    return Some(MultiBufferDiffHunk {
3651                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3652                        buffer_id: excerpt.buffer_id,
3653                        excerpt_id: excerpt.id,
3654                        buffer_range: hunk.buffer_range.clone(),
3655                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3656                    });
3657                }
3658            }
3659
3660            cursor.prev_excerpt();
3661            max_buffer_offset = usize::MAX;
3662        }
3663    }
3664
3665    pub fn has_diff_hunks(&self) -> bool {
3666        self.diffs.values().any(|diff| !diff.diff.is_empty())
3667    }
3668
3669    pub fn surrounding_word<T: ToOffset>(
3670        &self,
3671        start: T,
3672        for_completion: bool,
3673    ) -> (Range<usize>, Option<CharKind>) {
3674        let mut start = start.to_offset(self);
3675        let mut end = start;
3676        let mut next_chars = self.chars_at(start).peekable();
3677        let mut prev_chars = self.reversed_chars_at(start).peekable();
3678
3679        let classifier = self
3680            .char_classifier_at(start)
3681            .for_completion(for_completion);
3682
3683        let word_kind = cmp::max(
3684            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3685            next_chars.peek().copied().map(|c| classifier.kind(c)),
3686        );
3687
3688        for ch in prev_chars {
3689            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3690                start -= ch.len_utf8();
3691            } else {
3692                break;
3693            }
3694        }
3695
3696        for ch in next_chars {
3697            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3698                end += ch.len_utf8();
3699            } else {
3700                break;
3701            }
3702        }
3703
3704        (start..end, word_kind)
3705    }
3706
3707    pub fn is_singleton(&self) -> bool {
3708        self.singleton
3709    }
3710
3711    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3712        if self.singleton {
3713            self.excerpts
3714                .iter()
3715                .next()
3716                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3717        } else {
3718            None
3719        }
3720    }
3721
3722    pub fn len(&self) -> usize {
3723        self.diff_transforms.summary().output.len
3724    }
3725
3726    pub fn is_empty(&self) -> bool {
3727        self.excerpts.summary().text.len == 0
3728    }
3729
3730    pub fn widest_line_number(&self) -> u32 {
3731        self.excerpts.summary().widest_line_number + 1
3732    }
3733
3734    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3735        let range = range.start.to_offset(self)..range.end.to_offset(self);
3736        let mut excerpts = self.cursor::<usize>();
3737        excerpts.seek(&range.start);
3738
3739        let mut chunk;
3740        let mut has_trailing_newline;
3741        let excerpt_bytes;
3742        if let Some(region) = excerpts.region() {
3743            let mut bytes = region.buffer.bytes_in_range(
3744                region.buffer_range.start + range.start - region.range.start
3745                    ..(region.buffer_range.start + range.end - region.range.start)
3746                        .min(region.buffer_range.end),
3747            );
3748            chunk = bytes.next().unwrap_or(&[][..]);
3749            excerpt_bytes = Some(bytes);
3750            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3751            if chunk.is_empty() && has_trailing_newline {
3752                chunk = b"\n";
3753                has_trailing_newline = false;
3754            }
3755        } else {
3756            chunk = &[][..];
3757            excerpt_bytes = None;
3758            has_trailing_newline = false;
3759        };
3760
3761        MultiBufferBytes {
3762            range,
3763            cursor: excerpts,
3764            excerpt_bytes,
3765            has_trailing_newline,
3766            chunk,
3767        }
3768    }
3769
3770    pub fn reversed_bytes_in_range<T: ToOffset>(
3771        &self,
3772        range: Range<T>,
3773    ) -> ReversedMultiBufferBytes {
3774        let range = range.start.to_offset(self)..range.end.to_offset(self);
3775        let mut chunks = self.reversed_chunks_in_range(range.clone());
3776        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3777        ReversedMultiBufferBytes {
3778            range,
3779            chunks,
3780            chunk,
3781        }
3782    }
3783
3784    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3785        let mut cursor = self.cursor::<Point>();
3786        cursor.seek(&Point::new(start_row.0, 0));
3787        let mut result = MultiBufferRows {
3788            point: Point::new(0, 0),
3789            is_empty: self.excerpts.is_empty(),
3790            cursor,
3791        };
3792        result.seek(start_row);
3793        result
3794    }
3795
3796    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3797        let mut chunks = MultiBufferChunks {
3798            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3799            range: 0..0,
3800            excerpts: self.excerpts.cursor(&()),
3801            diff_transforms: self.diff_transforms.cursor(&()),
3802            diffs: &self.diffs,
3803            diff_base_chunks: None,
3804            excerpt_chunks: None,
3805            buffer_chunk: None,
3806            language_aware,
3807        };
3808        let range = range.start.to_offset(self)..range.end.to_offset(self);
3809        chunks.seek(range);
3810        chunks
3811    }
3812
3813    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3814        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3815    }
3816
3817    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3818        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3819    }
3820
3821    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3822        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3823    }
3824
3825    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3826        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3827            buffer.clip_point_utf16(Unclipped(point), bias)
3828        })
3829    }
3830
3831    pub fn offset_to_point(&self, offset: usize) -> Point {
3832        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3833    }
3834
3835    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3836        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3837    }
3838
3839    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3840        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3841    }
3842
3843    pub fn point_to_offset(&self, point: Point) -> usize {
3844        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3845    }
3846
3847    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3848        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3849    }
3850
3851    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3852        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3853    }
3854
3855    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3856        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3857    }
3858
3859    fn clip_dimension<D>(
3860        &self,
3861        position: D,
3862        bias: Bias,
3863        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3864    ) -> D
3865    where
3866        D: TextDimension + Ord + Sub<D, Output = D>,
3867    {
3868        let mut cursor = self.cursor();
3869        cursor.seek(&position);
3870        if let Some(region) = cursor.region() {
3871            if position >= region.range.end {
3872                return region.range.end;
3873            }
3874            let overshoot = position - region.range.start;
3875            let mut buffer_position = region.buffer_range.start;
3876            buffer_position.add_assign(&overshoot);
3877            let clipped_buffer_position =
3878                clip_buffer_position(&region.buffer, buffer_position, bias);
3879            let mut position = region.range.start;
3880            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3881            position
3882        } else {
3883            D::from_text_summary(&self.text_summary())
3884        }
3885    }
3886
3887    fn convert_dimension<D1, D2>(
3888        &self,
3889        key: D1,
3890        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3891    ) -> D2
3892    where
3893        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3894        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3895    {
3896        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3897        cursor.seek(&DimensionPair { key, value: None });
3898        if let Some(region) = cursor.region() {
3899            if key >= region.range.end.key {
3900                return region.range.end.value.unwrap();
3901            }
3902            let start_key = region.range.start.key;
3903            let start_value = region.range.start.value.unwrap();
3904            let buffer_start_key = region.buffer_range.start.key;
3905            let buffer_start_value = region.buffer_range.start.value.unwrap();
3906            let mut buffer_key = buffer_start_key;
3907            buffer_key.add_assign(&(key - start_key));
3908            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
3909            let mut result = start_value;
3910            result.add_assign(&(buffer_value - buffer_start_value));
3911            result
3912        } else {
3913            D2::from_text_summary(&self.text_summary())
3914        }
3915    }
3916
3917    pub fn point_to_buffer_offset<T: ToOffset>(
3918        &self,
3919        point: T,
3920    ) -> Option<(&BufferSnapshot, usize)> {
3921        let offset = point.to_offset(self);
3922        let mut cursor = self.cursor::<usize>();
3923        cursor.seek(&offset);
3924        let region = cursor.region()?;
3925        let overshoot = offset - region.range.start;
3926        let buffer_offset = region.buffer_range.start + overshoot;
3927        Some((region.buffer, buffer_offset))
3928    }
3929
3930    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
3931        let mut cursor = self.cursor::<Point>();
3932        cursor.seek(&point);
3933        let region = cursor.region()?;
3934        let overshoot = point - region.range.start;
3935        let buffer_offset = region.buffer_range.start + overshoot;
3936        Some((region.buffer, buffer_offset, region.is_main_buffer))
3937    }
3938
3939    pub fn suggested_indents(
3940        &self,
3941        rows: impl IntoIterator<Item = u32>,
3942        cx: &App,
3943    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3944        let mut result = BTreeMap::new();
3945
3946        let mut rows_for_excerpt = Vec::new();
3947        let mut cursor = self.cursor::<Point>();
3948        let mut rows = rows.into_iter().peekable();
3949        let mut prev_row = u32::MAX;
3950        let mut prev_language_indent_size = IndentSize::default();
3951
3952        while let Some(row) = rows.next() {
3953            cursor.seek(&Point::new(row, 0));
3954            let Some(region) = cursor.region() else {
3955                continue;
3956            };
3957
3958            // Retrieve the language and indent size once for each disjoint region being indented.
3959            let single_indent_size = if row.saturating_sub(1) == prev_row {
3960                prev_language_indent_size
3961            } else {
3962                region
3963                    .buffer
3964                    .language_indent_size_at(Point::new(row, 0), cx)
3965            };
3966            prev_language_indent_size = single_indent_size;
3967            prev_row = row;
3968
3969            let start_buffer_row = region.buffer_range.start.row;
3970            let start_multibuffer_row = region.range.start.row;
3971            let end_multibuffer_row = region.range.end.row;
3972
3973            rows_for_excerpt.push(row);
3974            while let Some(next_row) = rows.peek().copied() {
3975                if end_multibuffer_row > next_row {
3976                    rows_for_excerpt.push(next_row);
3977                    rows.next();
3978                } else {
3979                    break;
3980                }
3981            }
3982
3983            let buffer_rows = rows_for_excerpt
3984                .drain(..)
3985                .map(|row| start_buffer_row + row - start_multibuffer_row);
3986            let buffer_indents = region
3987                .buffer
3988                .suggested_indents(buffer_rows, single_indent_size);
3989            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
3990                (
3991                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
3992                    indent,
3993                )
3994            });
3995            result.extend(multibuffer_indents);
3996        }
3997
3998        result
3999    }
4000
4001    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4002        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4003            let mut size = buffer.indent_size_for_line(range.start.row);
4004            size.len = size
4005                .len
4006                .min(range.end.column)
4007                .saturating_sub(range.start.column);
4008            size
4009        } else {
4010            IndentSize::spaces(0)
4011        }
4012    }
4013
4014    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4015        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4016            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4017        } else {
4018            LineIndent::spaces(0)
4019        }
4020    }
4021
4022    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4023        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4024
4025        if self.settings_at(0, cx).extend_comment_on_newline {
4026            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4027                let delimiters = language_scope.line_comment_prefixes();
4028                for delimiter in delimiters {
4029                    if *self
4030                        .chars_at(Point::new(row.0, indent.len() as u32))
4031                        .take(delimiter.chars().count())
4032                        .collect::<String>()
4033                        .as_str()
4034                        == **delimiter
4035                    {
4036                        indent.push_str(&delimiter);
4037                        break;
4038                    }
4039                }
4040            }
4041        }
4042
4043        indent
4044    }
4045
4046    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4047        while row.0 > 0 {
4048            row.0 -= 1;
4049            if !self.is_line_blank(row) {
4050                return Some(row);
4051            }
4052        }
4053        None
4054    }
4055
4056    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4057        if let Some((_, range)) = self.buffer_line_for_row(row) {
4058            range.end.column - range.start.column
4059        } else {
4060            0
4061        }
4062    }
4063
4064    pub fn buffer_line_for_row(
4065        &self,
4066        row: MultiBufferRow,
4067    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4068        let mut cursor = self.cursor::<Point>();
4069        let point = Point::new(row.0, 0);
4070        cursor.seek(&point);
4071        let region = cursor.region()?;
4072        let overshoot = point.min(region.range.end) - region.range.start;
4073        let buffer_point = region.buffer_range.start + overshoot;
4074        if buffer_point.row > region.buffer_range.end.row {
4075            return None;
4076        }
4077        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4078        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4079            .min(region.buffer_range.end);
4080        Some((region.buffer, line_start..line_end))
4081    }
4082
4083    pub fn max_point(&self) -> Point {
4084        self.text_summary().lines
4085    }
4086
4087    pub fn max_row(&self) -> MultiBufferRow {
4088        MultiBufferRow(self.text_summary().lines.row)
4089    }
4090
4091    pub fn text_summary(&self) -> TextSummary {
4092        self.diff_transforms.summary().output
4093    }
4094
4095    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4096    where
4097        D: TextDimension,
4098        O: ToOffset,
4099    {
4100        let range = range.start.to_offset(self)..range.end.to_offset(self);
4101        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4102        cursor.seek(&range.start, Bias::Right, &());
4103
4104        let Some(first_transform) = cursor.item() else {
4105            return D::from_text_summary(&TextSummary::default());
4106        };
4107
4108        let diff_transform_start = cursor.start().0;
4109        let diff_transform_end = cursor.end(&()).0;
4110        let diff_start = range.start;
4111        let start_overshoot = diff_start - diff_transform_start;
4112        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4113
4114        let mut result = match first_transform {
4115            DiffTransform::BufferContent { .. } => {
4116                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4117                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4118                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4119            }
4120            DiffTransform::DeletedHunk {
4121                buffer_id,
4122                base_text_byte_range,
4123                has_trailing_newline,
4124                ..
4125            } => {
4126                let buffer_start = base_text_byte_range.start + start_overshoot;
4127                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4128                let Some(buffer_diff) = self.diffs.get(buffer_id) else {
4129                    panic!("{:?} is in non-existent deleted hunk", range.start)
4130                };
4131
4132                let include_trailing_newline =
4133                    *has_trailing_newline && range.end >= diff_transform_end;
4134                if include_trailing_newline {
4135                    buffer_end -= 1;
4136                }
4137
4138                let mut summary = buffer_diff
4139                    .base_text
4140                    .text_summary_for_range::<D, _>(buffer_start..buffer_end);
4141
4142                if include_trailing_newline {
4143                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4144                }
4145
4146                summary
4147            }
4148        };
4149        if range.end < diff_transform_end {
4150            return result;
4151        }
4152
4153        cursor.next(&());
4154        result.add_assign(&D::from_text_summary(&cursor.summary(
4155            &range.end,
4156            Bias::Right,
4157            &(),
4158        )));
4159
4160        let Some(last_transform) = cursor.item() else {
4161            return result;
4162        };
4163
4164        let overshoot = range.end - cursor.start().0;
4165        let suffix = match last_transform {
4166            DiffTransform::BufferContent { .. } => {
4167                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4168                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4169            }
4170            DiffTransform::DeletedHunk {
4171                base_text_byte_range,
4172                buffer_id,
4173                has_trailing_newline,
4174                ..
4175            } => {
4176                let buffer_end = base_text_byte_range.start + overshoot;
4177                let Some(buffer_diff) = self.diffs.get(buffer_id) else {
4178                    panic!("{:?} is in non-extant deleted hunk", range.end)
4179                };
4180
4181                let mut suffix = buffer_diff
4182                    .base_text
4183                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4184                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4185                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4186                }
4187                suffix
4188            }
4189        };
4190
4191        result.add_assign(&suffix);
4192        result
4193    }
4194
4195    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4196    where
4197        D: TextDimension,
4198    {
4199        // let mut range = range.start..range.end;
4200        let mut summary = D::zero(&());
4201        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4202        cursor.seek(&range.start, Bias::Right, &());
4203        if let Some(excerpt) = cursor.item() {
4204            let mut end_before_newline = cursor.end(&());
4205            if excerpt.has_trailing_newline {
4206                end_before_newline -= ExcerptOffset::new(1);
4207            }
4208
4209            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4210            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4211            let end_in_excerpt =
4212                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4213            summary.add_assign(
4214                &excerpt
4215                    .buffer
4216                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4217            );
4218
4219            if range.end > end_before_newline {
4220                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4221            }
4222
4223            cursor.next(&());
4224        }
4225
4226        if range.end > *cursor.start() {
4227            summary.add_assign(
4228                &cursor
4229                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4230                    .0,
4231            );
4232            if let Some(excerpt) = cursor.item() {
4233                range.end = cmp::max(*cursor.start(), range.end);
4234
4235                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4236                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4237                summary.add_assign(
4238                    &excerpt
4239                        .buffer
4240                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4241                );
4242            }
4243        }
4244
4245        summary
4246    }
4247
4248    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4249    where
4250        D: TextDimension + Ord + Sub<D, Output = D>,
4251    {
4252        self.summaries_for_anchors([anchor])[0]
4253    }
4254
4255    fn resolve_summary_for_anchor<D>(
4256        &self,
4257        anchor: &Anchor,
4258        excerpt_position: D,
4259        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4260    ) -> D
4261    where
4262        D: TextDimension + Ord + Sub<D, Output = D>,
4263    {
4264        loop {
4265            let transform_end_position = diff_transforms.end(&()).0 .0;
4266            let at_transform_end =
4267                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4268            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4269                diff_transforms.next(&());
4270                continue;
4271            }
4272
4273            let mut position = diff_transforms.start().1 .0;
4274            match diff_transforms.item() {
4275                Some(DiffTransform::DeletedHunk {
4276                    buffer_id,
4277                    base_text_byte_range,
4278                    ..
4279                }) => {
4280                    let mut in_deleted_hunk = false;
4281                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4282                        if let Some(diff) = self.diffs.get(buffer_id) {
4283                            if diff.base_text.can_resolve(&diff_base_anchor) {
4284                                let base_text_offset = diff_base_anchor.to_offset(&diff.base_text);
4285                                if base_text_offset >= base_text_byte_range.start
4286                                    && base_text_offset <= base_text_byte_range.end
4287                                {
4288                                    let position_in_hunk =
4289                                        diff.base_text.text_summary_for_range::<D, _>(
4290                                            base_text_byte_range.start..base_text_offset,
4291                                        );
4292                                    position.add_assign(&position_in_hunk);
4293                                    in_deleted_hunk = true;
4294                                } else if at_transform_end {
4295                                    diff_transforms.next(&());
4296                                    continue;
4297                                }
4298                            }
4299                        }
4300                    }
4301                    if !in_deleted_hunk {
4302                        position = diff_transforms.end(&()).1 .0;
4303                    }
4304                }
4305                _ => {
4306                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4307                        diff_transforms.next(&());
4308                        continue;
4309                    }
4310                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4311                    position.add_assign(&overshoot);
4312                }
4313            }
4314
4315            return position;
4316        }
4317    }
4318
4319    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4320        let mut cursor = self
4321            .excerpts
4322            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4323        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4324
4325        cursor.seek(&Some(locator), Bias::Left, &());
4326        if cursor.item().is_none() {
4327            cursor.next(&());
4328        }
4329
4330        let mut position = cursor.start().1;
4331        if let Some(excerpt) = cursor.item() {
4332            if excerpt.id == anchor.excerpt_id {
4333                let excerpt_buffer_start = excerpt
4334                    .buffer
4335                    .offset_for_anchor(&excerpt.range.context.start);
4336                let excerpt_buffer_end =
4337                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4338                let buffer_position = cmp::min(
4339                    excerpt_buffer_end,
4340                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4341                );
4342                if buffer_position > excerpt_buffer_start {
4343                    position.value += buffer_position - excerpt_buffer_start;
4344                }
4345            }
4346        }
4347        position
4348    }
4349
4350    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4351    where
4352        D: TextDimension + Ord + Sub<D, Output = D>,
4353        I: 'a + IntoIterator<Item = &'a Anchor>,
4354    {
4355        let mut anchors = anchors.into_iter().peekable();
4356        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4357        let mut diff_transforms_cursor = self
4358            .diff_transforms
4359            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4360        diff_transforms_cursor.next(&());
4361
4362        let mut summaries = Vec::new();
4363        while let Some(anchor) = anchors.peek() {
4364            let excerpt_id = anchor.excerpt_id;
4365            let excerpt_anchors = iter::from_fn(|| {
4366                let anchor = anchors.peek()?;
4367                if anchor.excerpt_id == excerpt_id {
4368                    Some(anchors.next().unwrap())
4369                } else {
4370                    None
4371                }
4372            });
4373
4374            let locator = self.excerpt_locator_for_id(excerpt_id);
4375            cursor.seek_forward(locator, Bias::Left, &());
4376            if cursor.item().is_none() {
4377                cursor.next(&());
4378            }
4379
4380            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4381            if let Some(excerpt) = cursor.item().filter(|excerpt| excerpt.id == excerpt_id) {
4382                let excerpt_buffer_start =
4383                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4384                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4385                for (buffer_summary, anchor) in excerpt
4386                    .buffer
4387                    .summaries_for_anchors_with_payload::<D, _, _>(
4388                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4389                    )
4390                {
4391                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4392                    let mut position = excerpt_start_position;
4393                    if summary > excerpt_buffer_start {
4394                        position.add_assign(&(summary - excerpt_buffer_start));
4395                    }
4396
4397                    if position > diff_transforms_cursor.start().0 .0 {
4398                        diff_transforms_cursor.seek_forward(
4399                            &ExcerptDimension(position),
4400                            Bias::Left,
4401                            &(),
4402                        );
4403                    }
4404
4405                    summaries.push(self.resolve_summary_for_anchor(
4406                        anchor,
4407                        position,
4408                        &mut diff_transforms_cursor,
4409                    ));
4410                }
4411            } else {
4412                diff_transforms_cursor.seek_forward(
4413                    &ExcerptDimension(excerpt_start_position),
4414                    Bias::Left,
4415                    &(),
4416                );
4417                let position = self.resolve_summary_for_anchor(
4418                    &Anchor::max(),
4419                    excerpt_start_position,
4420                    &mut diff_transforms_cursor,
4421                );
4422                summaries.extend(excerpt_anchors.map(|_| position));
4423            }
4424        }
4425
4426        summaries
4427    }
4428
4429    pub fn dimensions_from_points<'a, D>(
4430        &'a self,
4431        points: impl 'a + IntoIterator<Item = Point>,
4432    ) -> impl 'a + Iterator<Item = D>
4433    where
4434        D: TextDimension + Sub<D, Output = D>,
4435    {
4436        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4437        cursor.seek(&DimensionPair {
4438            key: Point::default(),
4439            value: None,
4440        });
4441        let mut points = points.into_iter();
4442        iter::from_fn(move || {
4443            let point = points.next()?;
4444
4445            cursor.seek_forward(&DimensionPair {
4446                key: point,
4447                value: None,
4448            });
4449
4450            if let Some(region) = cursor.region() {
4451                let overshoot = point - region.range.start.key;
4452                let buffer_point = region.buffer_range.start.key + overshoot;
4453                let mut position = region.range.start.value.unwrap();
4454                position.add_assign(
4455                    &region
4456                        .buffer
4457                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4458                );
4459                return Some(position);
4460            } else {
4461                return Some(D::from_text_summary(&self.text_summary()));
4462            }
4463        })
4464    }
4465
4466    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4467    where
4468        I: 'a + IntoIterator<Item = &'a Anchor>,
4469    {
4470        let mut anchors = anchors.into_iter().enumerate().peekable();
4471        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4472        cursor.next(&());
4473
4474        let mut result = Vec::new();
4475
4476        while let Some((_, anchor)) = anchors.peek() {
4477            let old_excerpt_id = anchor.excerpt_id;
4478
4479            // Find the location where this anchor's excerpt should be.
4480            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4481            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4482
4483            if cursor.item().is_none() {
4484                cursor.next(&());
4485            }
4486
4487            let next_excerpt = cursor.item();
4488            let prev_excerpt = cursor.prev_item();
4489
4490            // Process all of the anchors for this excerpt.
4491            while let Some((_, anchor)) = anchors.peek() {
4492                if anchor.excerpt_id != old_excerpt_id {
4493                    break;
4494                }
4495                let (anchor_ix, anchor) = anchors.next().unwrap();
4496                let mut anchor = *anchor;
4497
4498                // Leave min and max anchors unchanged if invalid or
4499                // if the old excerpt still exists at this location
4500                let mut kept_position = next_excerpt
4501                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4502                    || old_excerpt_id == ExcerptId::max()
4503                    || old_excerpt_id == ExcerptId::min();
4504
4505                // If the old excerpt no longer exists at this location, then attempt to
4506                // find an equivalent position for this anchor in an adjacent excerpt.
4507                if !kept_position {
4508                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4509                        if excerpt.contains(&anchor) {
4510                            anchor.excerpt_id = excerpt.id;
4511                            kept_position = true;
4512                            break;
4513                        }
4514                    }
4515                }
4516
4517                // If there's no adjacent excerpt that contains the anchor's position,
4518                // then report that the anchor has lost its position.
4519                if !kept_position {
4520                    anchor = if let Some(excerpt) = next_excerpt {
4521                        let mut text_anchor = excerpt
4522                            .range
4523                            .context
4524                            .start
4525                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4526                        if text_anchor
4527                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4528                            .is_gt()
4529                        {
4530                            text_anchor = excerpt.range.context.end;
4531                        }
4532                        Anchor {
4533                            buffer_id: Some(excerpt.buffer_id),
4534                            excerpt_id: excerpt.id,
4535                            text_anchor,
4536                            diff_base_anchor: None,
4537                        }
4538                    } else if let Some(excerpt) = prev_excerpt {
4539                        let mut text_anchor = excerpt
4540                            .range
4541                            .context
4542                            .end
4543                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4544                        if text_anchor
4545                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4546                            .is_lt()
4547                        {
4548                            text_anchor = excerpt.range.context.start;
4549                        }
4550                        Anchor {
4551                            buffer_id: Some(excerpt.buffer_id),
4552                            excerpt_id: excerpt.id,
4553                            text_anchor,
4554                            diff_base_anchor: None,
4555                        }
4556                    } else if anchor.text_anchor.bias == Bias::Left {
4557                        Anchor::min()
4558                    } else {
4559                        Anchor::max()
4560                    };
4561                }
4562
4563                result.push((anchor_ix, anchor, kept_position));
4564            }
4565        }
4566        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4567        result
4568    }
4569
4570    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4571        self.anchor_at(position, Bias::Left)
4572    }
4573
4574    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4575        self.anchor_at(position, Bias::Right)
4576    }
4577
4578    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4579        let offset = position.to_offset(self);
4580
4581        // Find the given position in the diff transforms. Determine the corresponding
4582        // offset in the excerpts, and whether the position is within a deleted hunk.
4583        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4584        diff_transforms.seek(&offset, Bias::Right, &());
4585
4586        if offset == diff_transforms.start().0 && bias == Bias::Left {
4587            if let Some(prev_item) = diff_transforms.prev_item() {
4588                match prev_item {
4589                    DiffTransform::DeletedHunk { .. } => {
4590                        diff_transforms.prev(&());
4591                    }
4592                    _ => {}
4593                }
4594            }
4595        }
4596        let offset_in_transform = offset - diff_transforms.start().0;
4597        let mut excerpt_offset = diff_transforms.start().1;
4598        let mut diff_base_anchor = None;
4599        if let Some(DiffTransform::DeletedHunk {
4600            buffer_id,
4601            base_text_byte_range,
4602            has_trailing_newline,
4603            ..
4604        }) = diff_transforms.item()
4605        {
4606            let diff_base = self.diffs.get(buffer_id).expect("missing diff base");
4607            if offset_in_transform > base_text_byte_range.len() {
4608                debug_assert!(*has_trailing_newline);
4609                bias = Bias::Right;
4610            } else {
4611                diff_base_anchor = Some(
4612                    diff_base
4613                        .base_text
4614                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4615                );
4616                bias = Bias::Left;
4617            }
4618        } else {
4619            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4620        };
4621
4622        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4623            return Anchor {
4624                buffer_id: Some(buffer_id),
4625                excerpt_id: *excerpt_id,
4626                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4627                diff_base_anchor,
4628            };
4629        }
4630
4631        let mut excerpts = self
4632            .excerpts
4633            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4634        excerpts.seek(&excerpt_offset, Bias::Right, &());
4635        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4636            excerpts.prev(&());
4637        }
4638        if let Some(excerpt) = excerpts.item() {
4639            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4640            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4641                overshoot -= 1;
4642                bias = Bias::Right;
4643            }
4644
4645            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4646            let text_anchor =
4647                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4648            Anchor {
4649                buffer_id: Some(excerpt.buffer_id),
4650                excerpt_id: excerpt.id,
4651                text_anchor,
4652                diff_base_anchor,
4653            }
4654        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4655            Anchor::min()
4656        } else {
4657            Anchor::max()
4658        }
4659    }
4660
4661    /// Returns an anchor for the given excerpt and text anchor,
4662    /// returns None if the excerpt_id is no longer valid.
4663    pub fn anchor_in_excerpt(
4664        &self,
4665        excerpt_id: ExcerptId,
4666        text_anchor: text::Anchor,
4667    ) -> Option<Anchor> {
4668        let locator = self.excerpt_locator_for_id(excerpt_id);
4669        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4670        cursor.seek(locator, Bias::Left, &());
4671        if let Some(excerpt) = cursor.item() {
4672            if excerpt.id == excerpt_id {
4673                let text_anchor = excerpt.clip_anchor(text_anchor);
4674                drop(cursor);
4675                return Some(Anchor {
4676                    buffer_id: Some(excerpt.buffer_id),
4677                    excerpt_id,
4678                    text_anchor,
4679                    diff_base_anchor: None,
4680                });
4681            }
4682        }
4683        None
4684    }
4685
4686    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4687        Some(self.excerpt(excerpt_id)?.range.context.clone())
4688    }
4689
4690    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4691        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4692            true
4693        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4694            excerpt.buffer.can_resolve(&anchor.text_anchor)
4695        } else {
4696            false
4697        }
4698    }
4699
4700    pub fn excerpts(
4701        &self,
4702    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4703        self.excerpts
4704            .iter()
4705            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4706    }
4707
4708    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4709        let excerpts = self.excerpts.cursor(&());
4710        let diff_transforms = self.diff_transforms.cursor(&());
4711        MultiBufferCursor {
4712            excerpts,
4713            diff_transforms,
4714            diffs: &self.diffs,
4715            cached_region: None,
4716        }
4717    }
4718
4719    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4720        let start_locator = self.excerpt_locator_for_id(id);
4721        let mut excerpts = self
4722            .excerpts
4723            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4724        excerpts.seek(&Some(start_locator), Bias::Left, &());
4725        excerpts.prev(&());
4726
4727        let mut diff_transforms = self
4728            .diff_transforms
4729            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4730        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4731        if diff_transforms.end(&()).1 < excerpts.start().1 {
4732            diff_transforms.next(&());
4733        }
4734
4735        let excerpt = excerpts.item()?;
4736        Some(MultiBufferExcerpt {
4737            excerpt,
4738            offset: diff_transforms.start().0 .0,
4739            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4740            excerpt_offset: excerpts.start().1.clone(),
4741            diff_transforms,
4742        })
4743    }
4744
4745    pub fn excerpt_boundaries_in_range<R, T>(
4746        &self,
4747        range: R,
4748    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4749    where
4750        R: RangeBounds<T>,
4751        T: ToOffset,
4752    {
4753        let start_offset;
4754        let start = match range.start_bound() {
4755            Bound::Included(start) => {
4756                start_offset = start.to_offset(self);
4757                Bound::Included(start_offset)
4758            }
4759            Bound::Excluded(_) => {
4760                panic!("not supported")
4761            }
4762            Bound::Unbounded => {
4763                start_offset = 0;
4764                Bound::Unbounded
4765            }
4766        };
4767        let end = match range.end_bound() {
4768            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4769            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4770            Bound::Unbounded => Bound::Unbounded,
4771        };
4772        let bounds = (start, end);
4773
4774        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4775        cursor.seek(&DimensionPair {
4776            key: start_offset,
4777            value: None,
4778        });
4779
4780        if cursor
4781            .region()
4782            .is_some_and(|region| bounds.contains(&region.range.start.key))
4783        {
4784            cursor.prev_excerpt();
4785        } else {
4786            cursor.seek_to_start_of_current_excerpt();
4787        }
4788        let mut prev_region = cursor.region();
4789
4790        cursor.next_excerpt();
4791
4792        let mut visited_end = false;
4793        iter::from_fn(move || {
4794            if self.singleton {
4795                return None;
4796            }
4797
4798            let next_region = cursor.region();
4799            cursor.next_excerpt();
4800
4801            let next_region_start = if let Some(region) = &next_region {
4802                if !bounds.contains(&region.range.start.key) {
4803                    return None;
4804                }
4805                region.range.start.value.unwrap()
4806            } else {
4807                if !bounds.contains(&self.len()) {
4808                    return None;
4809                }
4810                self.max_point()
4811            };
4812            let next_region_end = if let Some(region) = cursor.region() {
4813                region.range.start.value.unwrap()
4814            } else {
4815                self.max_point()
4816            };
4817
4818            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4819                id: region.excerpt.id,
4820                buffer: region.excerpt.buffer.clone(),
4821                buffer_id: region.excerpt.buffer_id,
4822                range: region.excerpt.range.clone(),
4823                end_row: MultiBufferRow(next_region_start.row),
4824            });
4825
4826            let next = next_region.as_ref().map(|region| ExcerptInfo {
4827                id: region.excerpt.id,
4828                buffer: region.excerpt.buffer.clone(),
4829                buffer_id: region.excerpt.buffer_id,
4830                range: region.excerpt.range.clone(),
4831                end_row: if region.excerpt.has_trailing_newline {
4832                    MultiBufferRow(next_region_end.row - 1)
4833                } else {
4834                    MultiBufferRow(next_region_end.row)
4835                },
4836            });
4837
4838            if next.is_none() {
4839                if visited_end {
4840                    return None;
4841                } else {
4842                    visited_end = true;
4843                }
4844            }
4845
4846            let row = MultiBufferRow(next_region_start.row);
4847
4848            prev_region = next_region;
4849
4850            Some(ExcerptBoundary { row, prev, next })
4851        })
4852    }
4853
4854    pub fn edit_count(&self) -> usize {
4855        self.edit_count
4856    }
4857
4858    pub fn non_text_state_update_count(&self) -> usize {
4859        self.non_text_state_update_count
4860    }
4861
4862    /// Returns the smallest enclosing bracket ranges containing the given range or
4863    /// None if no brackets contain range or the range is not contained in a single
4864    /// excerpt
4865    ///
4866    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4867    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4868        &self,
4869        range: Range<T>,
4870        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4871    ) -> Option<(Range<usize>, Range<usize>)> {
4872        let range = range.start.to_offset(self)..range.end.to_offset(self);
4873        let mut excerpt = self.excerpt_containing(range.clone())?;
4874        let buffer = excerpt.buffer();
4875        let excerpt_buffer_range = excerpt.buffer_range();
4876
4877        // Filter to ranges contained in the excerpt
4878        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4879            excerpt_buffer_range.contains(&open.start)
4880                && excerpt_buffer_range.contains(&close.end)
4881                && range_filter.map_or(true, |filter| filter(buffer, open, close))
4882        };
4883
4884        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4885            excerpt.map_range_to_buffer(range),
4886            Some(&range_filter),
4887        )?;
4888
4889        Some((
4890            excerpt.map_range_from_buffer(open),
4891            excerpt.map_range_from_buffer(close),
4892        ))
4893    }
4894
4895    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4896    /// not contained in a single excerpt
4897    pub fn enclosing_bracket_ranges<T: ToOffset>(
4898        &self,
4899        range: Range<T>,
4900    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4901        let range = range.start.to_offset(self)..range.end.to_offset(self);
4902        let mut excerpt = self.excerpt_containing(range.clone())?;
4903
4904        Some(
4905            excerpt
4906                .buffer()
4907                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4908                .filter_map(move |(open, close)| {
4909                    if excerpt.contains_buffer_range(open.start..close.end) {
4910                        Some((
4911                            excerpt.map_range_from_buffer(open),
4912                            excerpt.map_range_from_buffer(close),
4913                        ))
4914                    } else {
4915                        None
4916                    }
4917                }),
4918        )
4919    }
4920
4921    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4922    /// not contained in a single excerpt
4923    pub fn text_object_ranges<T: ToOffset>(
4924        &self,
4925        range: Range<T>,
4926        options: TreeSitterOptions,
4927    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4928        let range = range.start.to_offset(self)..range.end.to_offset(self);
4929        self.excerpt_containing(range.clone())
4930            .map(|mut excerpt| {
4931                excerpt
4932                    .buffer()
4933                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4934                    .filter_map(move |(range, text_object)| {
4935                        if excerpt.contains_buffer_range(range.clone()) {
4936                            Some((excerpt.map_range_from_buffer(range), text_object))
4937                        } else {
4938                            None
4939                        }
4940                    })
4941            })
4942            .into_iter()
4943            .flatten()
4944    }
4945
4946    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4947    /// not contained in a single excerpt
4948    pub fn bracket_ranges<T: ToOffset>(
4949        &self,
4950        range: Range<T>,
4951    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4952        let range = range.start.to_offset(self)..range.end.to_offset(self);
4953        let mut excerpt = self.excerpt_containing(range.clone())?;
4954
4955        Some(
4956            excerpt
4957                .buffer()
4958                .bracket_ranges(excerpt.map_range_to_buffer(range))
4959                .filter_map(move |(start_bracket_range, close_bracket_range)| {
4960                    let buffer_range = start_bracket_range.start..close_bracket_range.end;
4961                    if excerpt.contains_buffer_range(buffer_range) {
4962                        Some((
4963                            excerpt.map_range_from_buffer(start_bracket_range),
4964                            excerpt.map_range_from_buffer(close_bracket_range),
4965                        ))
4966                    } else {
4967                        None
4968                    }
4969                }),
4970        )
4971    }
4972
4973    pub fn redacted_ranges<'a, T: ToOffset>(
4974        &'a self,
4975        range: Range<T>,
4976        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
4977    ) -> impl Iterator<Item = Range<usize>> + 'a {
4978        let range = range.start.to_offset(self)..range.end.to_offset(self);
4979        self.lift_buffer_metadata(range, move |buffer, range| {
4980            if redaction_enabled(buffer.file()) {
4981                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
4982            } else {
4983                None
4984            }
4985        })
4986        .map(|(range, _, _)| range)
4987    }
4988
4989    pub fn runnable_ranges(
4990        &self,
4991        range: Range<Anchor>,
4992    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
4993        let range = range.start.to_offset(self)..range.end.to_offset(self);
4994        self.lift_buffer_metadata(range, move |buffer, range| {
4995            Some(
4996                buffer
4997                    .runnable_ranges(range.clone())
4998                    .filter(move |runnable| {
4999                        runnable.run_range.start >= range.start
5000                            && runnable.run_range.end < range.end
5001                    })
5002                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5003            )
5004        })
5005        .map(|(run_range, runnable, _)| language::RunnableRange {
5006            run_range,
5007            ..runnable
5008        })
5009    }
5010
5011    pub fn line_indents(
5012        &self,
5013        start_row: MultiBufferRow,
5014        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5015    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5016        let max_point = self.max_point();
5017        let mut cursor = self.cursor::<Point>();
5018        cursor.seek(&Point::new(start_row.0, 0));
5019        iter::from_fn(move || {
5020            let mut region = cursor.region()?;
5021            while !buffer_filter(&region.excerpt.buffer) {
5022                cursor.next();
5023                region = cursor.region()?;
5024            }
5025            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5026            let buffer_start_row =
5027                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5028
5029            let buffer_end_row = if region.is_main_buffer
5030                && (region.has_trailing_newline || region.range.end == max_point)
5031            {
5032                region.buffer_range.end.row
5033            } else {
5034                region.buffer_range.end.row.saturating_sub(1)
5035            };
5036
5037            let line_indents = region
5038                .buffer
5039                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5040            cursor.next();
5041            return Some(line_indents.map(move |(buffer_row, indent)| {
5042                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5043                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5044            }));
5045        })
5046        .flatten()
5047    }
5048
5049    pub fn reversed_line_indents(
5050        &self,
5051        end_row: MultiBufferRow,
5052        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5053    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5054        let max_point = self.max_point();
5055        let mut cursor = self.cursor::<Point>();
5056        cursor.seek(&Point::new(end_row.0, 0));
5057        iter::from_fn(move || {
5058            let mut region = cursor.region()?;
5059            while !buffer_filter(&region.excerpt.buffer) {
5060                cursor.prev();
5061                region = cursor.region()?;
5062            }
5063
5064            let buffer_start_row = region.buffer_range.start.row;
5065            let buffer_end_row = if region.is_main_buffer
5066                && (region.has_trailing_newline || region.range.end == max_point)
5067            {
5068                region.buffer_range.end.row + 1
5069            } else {
5070                region.buffer_range.end.row
5071            };
5072
5073            let overshoot = end_row.0 - region.range.start.row;
5074            let buffer_end_row =
5075                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5076
5077            let line_indents = region
5078                .buffer
5079                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5080            cursor.prev();
5081            return Some(line_indents.map(move |(buffer_row, indent)| {
5082                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5083                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5084            }));
5085        })
5086        .flatten()
5087    }
5088
5089    pub async fn enclosing_indent(
5090        &self,
5091        mut target_row: MultiBufferRow,
5092    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5093        let max_row = MultiBufferRow(self.max_point().row);
5094        if target_row >= max_row {
5095            return None;
5096        }
5097
5098        let mut target_indent = self.line_indent_for_row(target_row);
5099
5100        // If the current row is at the start of an indented block, we want to return this
5101        // block as the enclosing indent.
5102        if !target_indent.is_line_empty() && target_row < max_row {
5103            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5104            if !next_line_indent.is_line_empty()
5105                && target_indent.raw_len() < next_line_indent.raw_len()
5106            {
5107                target_indent = next_line_indent;
5108                target_row.0 += 1;
5109            }
5110        }
5111
5112        const SEARCH_ROW_LIMIT: u32 = 25000;
5113        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5114        const YIELD_INTERVAL: u32 = 100;
5115
5116        let mut accessed_row_counter = 0;
5117
5118        // If there is a blank line at the current row, search for the next non indented lines
5119        if target_indent.is_line_empty() {
5120            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5121            let end =
5122                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5123
5124            let mut non_empty_line_above = None;
5125            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5126                if row < start {
5127                    break;
5128                }
5129                accessed_row_counter += 1;
5130                if accessed_row_counter == YIELD_INTERVAL {
5131                    accessed_row_counter = 0;
5132                    yield_now().await;
5133                }
5134                if !indent.is_line_empty() {
5135                    non_empty_line_above = Some((row, indent));
5136                    break;
5137                }
5138            }
5139
5140            let mut non_empty_line_below = None;
5141            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5142                if row > end {
5143                    break;
5144                }
5145                accessed_row_counter += 1;
5146                if accessed_row_counter == YIELD_INTERVAL {
5147                    accessed_row_counter = 0;
5148                    yield_now().await;
5149                }
5150                if !indent.is_line_empty() {
5151                    non_empty_line_below = Some((row, indent));
5152                    break;
5153                }
5154            }
5155
5156            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5157                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5158                    if above_indent.raw_len() >= below_indent.raw_len() {
5159                        (above_row, above_indent)
5160                    } else {
5161                        (below_row, below_indent)
5162                    }
5163                }
5164                (Some(above), None) => above,
5165                (None, Some(below)) => below,
5166                _ => return None,
5167            };
5168
5169            target_indent = indent;
5170            target_row = row;
5171        }
5172
5173        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5174        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5175
5176        let mut start_indent = None;
5177        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5178            if row < start {
5179                break;
5180            }
5181            accessed_row_counter += 1;
5182            if accessed_row_counter == YIELD_INTERVAL {
5183                accessed_row_counter = 0;
5184                yield_now().await;
5185            }
5186            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5187                start_indent = Some((row, indent));
5188                break;
5189            }
5190        }
5191        let (start_row, start_indent_size) = start_indent?;
5192
5193        let mut end_indent = (end, None);
5194        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5195            if row > end {
5196                break;
5197            }
5198            accessed_row_counter += 1;
5199            if accessed_row_counter == YIELD_INTERVAL {
5200                accessed_row_counter = 0;
5201                yield_now().await;
5202            }
5203            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5204                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5205                break;
5206            }
5207        }
5208        let (end_row, end_indent_size) = end_indent;
5209
5210        let indent = if let Some(end_indent_size) = end_indent_size {
5211            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5212                start_indent_size
5213            } else {
5214                end_indent_size
5215            }
5216        } else {
5217            start_indent_size
5218        };
5219
5220        Some((start_row..end_row, indent))
5221    }
5222
5223    pub fn indent_guides_in_range<T: ToPoint>(
5224        &self,
5225        range: Range<T>,
5226        ignore_disabled_for_language: bool,
5227        cx: &App,
5228    ) -> impl Iterator<Item = IndentGuide> {
5229        let range = range.start.to_point(self)..range.end.to_point(self);
5230        let start_row = MultiBufferRow(range.start.row);
5231        let end_row = MultiBufferRow(range.end.row);
5232
5233        let mut row_indents = self.line_indents(start_row, |buffer| {
5234            let settings =
5235                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5236            settings.indent_guides.enabled || ignore_disabled_for_language
5237        });
5238
5239        let mut result = Vec::new();
5240        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5241
5242        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5243            if first_row > end_row {
5244                break;
5245            }
5246            let current_depth = indent_stack.len() as u32;
5247
5248            let settings =
5249                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5250            let tab_size = settings.tab_size.get() as u32;
5251
5252            // When encountering empty, continue until found useful line indent
5253            // then add to the indent stack with the depth found
5254            let mut found_indent = false;
5255            let mut last_row = first_row;
5256            if line_indent.is_line_empty() {
5257                while !found_indent {
5258                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5259                        break;
5260                    };
5261                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5262                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5263                        break;
5264                    }
5265
5266                    if new_line_indent.is_line_empty() {
5267                        continue;
5268                    }
5269                    last_row = target_row.min(end_row);
5270                    line_indent = new_line_indent;
5271                    found_indent = true;
5272                    break;
5273                }
5274            } else {
5275                found_indent = true
5276            }
5277
5278            let depth = if found_indent {
5279                line_indent.len(tab_size) / tab_size
5280                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5281            } else {
5282                current_depth
5283            };
5284
5285            match depth.cmp(&current_depth) {
5286                cmp::Ordering::Less => {
5287                    for _ in 0..(current_depth - depth) {
5288                        let mut indent = indent_stack.pop().unwrap();
5289                        if last_row != first_row {
5290                            // In this case, we landed on an empty row, had to seek forward,
5291                            // and discovered that the indent we where on is ending.
5292                            // This means that the last display row must
5293                            // be on line that ends this indent range, so we
5294                            // should display the range up to the first non-empty line
5295                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5296                        }
5297
5298                        result.push(indent)
5299                    }
5300                }
5301                cmp::Ordering::Greater => {
5302                    for next_depth in current_depth..depth {
5303                        indent_stack.push(IndentGuide {
5304                            buffer_id: buffer.remote_id(),
5305                            start_row: first_row,
5306                            end_row: last_row,
5307                            depth: next_depth,
5308                            tab_size,
5309                            settings: settings.indent_guides,
5310                        });
5311                    }
5312                }
5313                _ => {}
5314            }
5315
5316            for indent in indent_stack.iter_mut() {
5317                indent.end_row = last_row;
5318            }
5319        }
5320
5321        result.extend(indent_stack);
5322        result.into_iter()
5323    }
5324
5325    pub fn trailing_excerpt_update_count(&self) -> usize {
5326        self.trailing_excerpt_update_count
5327    }
5328
5329    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5330        self.point_to_buffer_offset(point)
5331            .and_then(|(buffer, _)| buffer.file())
5332    }
5333
5334    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5335        self.point_to_buffer_offset(point)
5336            .and_then(|(buffer, offset)| buffer.language_at(offset))
5337    }
5338
5339    pub fn settings_at<'a, T: ToOffset>(
5340        &'a self,
5341        point: T,
5342        cx: &'a App,
5343    ) -> Cow<'a, LanguageSettings> {
5344        let mut language = None;
5345        let mut file = None;
5346        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5347            language = buffer.language_at(offset);
5348            file = buffer.file();
5349        }
5350        language_settings(language.map(|l| l.name()), file, cx)
5351    }
5352
5353    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5354        self.point_to_buffer_offset(point)
5355            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5356    }
5357
5358    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5359        self.point_to_buffer_offset(point)
5360            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5361            .unwrap_or_default()
5362    }
5363
5364    pub fn language_indent_size_at<T: ToOffset>(
5365        &self,
5366        position: T,
5367        cx: &App,
5368    ) -> Option<IndentSize> {
5369        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5370        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5371    }
5372
5373    pub fn is_dirty(&self) -> bool {
5374        self.is_dirty
5375    }
5376
5377    pub fn has_deleted_file(&self) -> bool {
5378        self.has_deleted_file
5379    }
5380
5381    pub fn has_conflict(&self) -> bool {
5382        self.has_conflict
5383    }
5384
5385    pub fn has_diagnostics(&self) -> bool {
5386        self.excerpts
5387            .iter()
5388            .any(|excerpt| excerpt.buffer.has_diagnostics())
5389    }
5390
5391    pub fn diagnostic_group(
5392        &self,
5393        buffer_id: BufferId,
5394        group_id: usize,
5395    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5396        self.lift_buffer_metadata(0..self.len(), move |buffer, _| {
5397            if buffer.remote_id() != buffer_id {
5398                return None;
5399            };
5400            Some(
5401                buffer
5402                    .diagnostic_group(group_id)
5403                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5404            )
5405        })
5406        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5407    }
5408
5409    pub fn diagnostics_in_range<'a, T, O>(
5410        &'a self,
5411        range: Range<T>,
5412    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
5413    where
5414        T: 'a + ToOffset,
5415        O: 'a + text::FromAnchor + Copy + TextDimension + Ord + Sub<O, Output = O> + fmt::Debug,
5416    {
5417        let range = range.start.to_offset(self)..range.end.to_offset(self);
5418        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5419            Some(
5420                buffer
5421                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5422                    .map(|entry| (entry.range, entry.diagnostic)),
5423            )
5424        })
5425        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5426    }
5427
5428    pub fn syntax_ancestor<T: ToOffset>(
5429        &self,
5430        range: Range<T>,
5431    ) -> Option<(tree_sitter::Node, Range<usize>)> {
5432        let range = range.start.to_offset(self)..range.end.to_offset(self);
5433        let mut excerpt = self.excerpt_containing(range.clone())?;
5434        let node = excerpt
5435            .buffer()
5436            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5437        Some((node, excerpt.map_range_from_buffer(node.byte_range())))
5438    }
5439
5440    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5441        let (excerpt_id, _, buffer) = self.as_singleton()?;
5442        let outline = buffer.outline(theme)?;
5443        Some(Outline::new(
5444            outline
5445                .items
5446                .into_iter()
5447                .flat_map(|item| {
5448                    Some(OutlineItem {
5449                        depth: item.depth,
5450                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5451                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5452                        text: item.text,
5453                        highlight_ranges: item.highlight_ranges,
5454                        name_ranges: item.name_ranges,
5455                        body_range: item.body_range.and_then(|body_range| {
5456                            Some(
5457                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5458                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5459                            )
5460                        }),
5461                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5462                            Some(
5463                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5464                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5465                            )
5466                        }),
5467                    })
5468                })
5469                .collect(),
5470        ))
5471    }
5472
5473    pub fn symbols_containing<T: ToOffset>(
5474        &self,
5475        offset: T,
5476        theme: Option<&SyntaxTheme>,
5477    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5478        let anchor = self.anchor_before(offset);
5479        let excerpt_id = anchor.excerpt_id;
5480        let excerpt = self.excerpt(excerpt_id)?;
5481        Some((
5482            excerpt.buffer_id,
5483            excerpt
5484                .buffer
5485                .symbols_containing(anchor.text_anchor, theme)
5486                .into_iter()
5487                .flatten()
5488                .flat_map(|item| {
5489                    Some(OutlineItem {
5490                        depth: item.depth,
5491                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5492                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5493                        text: item.text,
5494                        highlight_ranges: item.highlight_ranges,
5495                        name_ranges: item.name_ranges,
5496                        body_range: item.body_range.and_then(|body_range| {
5497                            Some(
5498                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5499                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5500                            )
5501                        }),
5502                        annotation_range: item.annotation_range.and_then(|body_range| {
5503                            Some(
5504                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5505                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5506                            )
5507                        }),
5508                    })
5509                })
5510                .collect(),
5511        ))
5512    }
5513
5514    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5515        if id == ExcerptId::min() {
5516            Locator::min_ref()
5517        } else if id == ExcerptId::max() {
5518            Locator::max_ref()
5519        } else {
5520            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5521            cursor.seek(&id, Bias::Left, &());
5522            if let Some(entry) = cursor.item() {
5523                if entry.id == id {
5524                    return &entry.locator;
5525                }
5526            }
5527            panic!("invalid excerpt id {:?}", id)
5528        }
5529    }
5530
5531    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5532    fn excerpt_locators_for_ids(
5533        &self,
5534        ids: impl IntoIterator<Item = ExcerptId>,
5535    ) -> SmallVec<[Locator; 1]> {
5536        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5537        sorted_ids.sort_unstable();
5538        let mut locators = SmallVec::new();
5539
5540        while sorted_ids.last() == Some(&ExcerptId::max()) {
5541            sorted_ids.pop();
5542            if let Some(mapping) = self.excerpt_ids.last() {
5543                locators.push(mapping.locator.clone());
5544            }
5545        }
5546
5547        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5548        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5549            sorted_ids.next();
5550            if let Some(mapping) = self.excerpt_ids.first() {
5551                locators.push(mapping.locator.clone());
5552            }
5553        }
5554
5555        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5556        for id in sorted_ids {
5557            if cursor.seek_forward(&id, Bias::Left, &()) {
5558                locators.push(cursor.item().unwrap().locator.clone());
5559            } else {
5560                panic!("invalid excerpt id {:?}", id);
5561            }
5562        }
5563
5564        locators.sort_unstable();
5565        locators
5566    }
5567
5568    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5569        Some(self.excerpt(excerpt_id)?.buffer_id)
5570    }
5571
5572    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5573        Some(&self.excerpt(excerpt_id)?.buffer)
5574    }
5575
5576    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5577        let mut cursor = self
5578            .excerpts
5579            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5580        let locator = self.excerpt_locator_for_id(excerpt_id);
5581        if cursor.seek(&Some(locator), Bias::Left, &()) {
5582            let start = cursor.start().1.clone();
5583            let end = cursor.end(&()).1;
5584            let mut diff_transforms = self
5585                .diff_transforms
5586                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5587            diff_transforms.seek(&start, Bias::Left, &());
5588            let overshoot = start.0 - diff_transforms.start().0 .0;
5589            let start = diff_transforms.start().1 .0 + overshoot;
5590            diff_transforms.seek(&end, Bias::Right, &());
5591            let overshoot = end.0 - diff_transforms.start().0 .0;
5592            let end = diff_transforms.start().1 .0 + overshoot;
5593            Some(start..end)
5594        } else {
5595            None
5596        }
5597    }
5598
5599    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5600        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5601        let locator = self.excerpt_locator_for_id(excerpt_id);
5602        if cursor.seek(&Some(locator), Bias::Left, &()) {
5603            if let Some(excerpt) = cursor.item() {
5604                return Some(excerpt.range.context.clone());
5605            }
5606        }
5607        None
5608    }
5609
5610    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5611        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5612        let locator = self.excerpt_locator_for_id(excerpt_id);
5613        cursor.seek(&Some(locator), Bias::Left, &());
5614        if let Some(excerpt) = cursor.item() {
5615            if excerpt.id == excerpt_id {
5616                return Some(excerpt);
5617            }
5618        }
5619        None
5620    }
5621
5622    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5623    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5624        let range = range.start.to_offset(self)..range.end.to_offset(self);
5625        let mut cursor = self.cursor::<usize>();
5626        cursor.seek(&range.start);
5627
5628        let start_excerpt = cursor.excerpt()?;
5629        if range.end != range.start {
5630            cursor.seek_forward(&range.end);
5631            if cursor.excerpt()?.id != start_excerpt.id {
5632                return None;
5633            }
5634        }
5635
5636        cursor.seek_to_start_of_current_excerpt();
5637        let region = cursor.region()?;
5638        let offset = region.range.start;
5639        let buffer_offset = region.buffer_range.start;
5640        let excerpt_offset = cursor.excerpts.start().clone();
5641        Some(MultiBufferExcerpt {
5642            diff_transforms: cursor.diff_transforms,
5643            excerpt: start_excerpt,
5644            offset,
5645            buffer_offset,
5646            excerpt_offset,
5647        })
5648    }
5649
5650    pub fn selections_in_range<'a>(
5651        &'a self,
5652        range: &'a Range<Anchor>,
5653        include_local: bool,
5654    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5655        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5656        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5657        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5658        cursor.seek(start_locator, Bias::Left, &());
5659        cursor
5660            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5661            .flat_map(move |excerpt| {
5662                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5663                if excerpt.id == range.start.excerpt_id {
5664                    query_range.start = range.start.text_anchor;
5665                }
5666                if excerpt.id == range.end.excerpt_id {
5667                    query_range.end = range.end.text_anchor;
5668                }
5669
5670                excerpt
5671                    .buffer
5672                    .selections_in_range(query_range, include_local)
5673                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5674                        selections.map(move |selection| {
5675                            let mut start = Anchor {
5676                                buffer_id: Some(excerpt.buffer_id),
5677                                excerpt_id: excerpt.id,
5678                                text_anchor: selection.start,
5679                                diff_base_anchor: None,
5680                            };
5681                            let mut end = Anchor {
5682                                buffer_id: Some(excerpt.buffer_id),
5683                                excerpt_id: excerpt.id,
5684                                text_anchor: selection.end,
5685                                diff_base_anchor: None,
5686                            };
5687                            if range.start.cmp(&start, self).is_gt() {
5688                                start = range.start;
5689                            }
5690                            if range.end.cmp(&end, self).is_lt() {
5691                                end = range.end;
5692                            }
5693
5694                            (
5695                                replica_id,
5696                                line_mode,
5697                                cursor_shape,
5698                                Selection {
5699                                    id: selection.id,
5700                                    start,
5701                                    end,
5702                                    reversed: selection.reversed,
5703                                    goal: selection.goal,
5704                                },
5705                            )
5706                        })
5707                    })
5708            })
5709    }
5710
5711    pub fn show_headers(&self) -> bool {
5712        self.show_headers
5713    }
5714}
5715
5716#[cfg(any(test, feature = "test-support"))]
5717impl MultiBufferSnapshot {
5718    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5719        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5720        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5721        start..end
5722    }
5723
5724    #[cfg(any(test, feature = "test-support"))]
5725    fn check_invariants(&self) {
5726        let excerpts = self.excerpts.items(&());
5727        let excerpt_ids = self.excerpt_ids.items(&());
5728
5729        for (ix, excerpt) in excerpts.iter().enumerate() {
5730            if ix == 0 {
5731                if excerpt.locator <= Locator::min() {
5732                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5733                }
5734            } else if excerpt.locator <= excerpts[ix - 1].locator {
5735                panic!("excerpts are out-of-order: {:?}", excerpts);
5736            }
5737        }
5738
5739        for (ix, entry) in excerpt_ids.iter().enumerate() {
5740            if ix == 0 {
5741                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5742                    panic!("invalid first excerpt id {:?}", entry.id);
5743                }
5744            } else if entry.id <= excerpt_ids[ix - 1].id {
5745                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5746            }
5747        }
5748
5749        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5750            panic!(
5751                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5752                self.excerpts.summary().text.len,
5753                self.diff_transforms.summary().input,
5754                self.diff_transforms.items(&()),
5755            );
5756        }
5757
5758        let mut prev_transform: Option<&DiffTransform> = None;
5759        for item in self.diff_transforms.iter() {
5760            if let DiffTransform::BufferContent {
5761                summary,
5762                inserted_hunk_anchor,
5763            } = item
5764            {
5765                if let Some(DiffTransform::BufferContent {
5766                    inserted_hunk_anchor: prev_inserted_hunk_anchor,
5767                    ..
5768                }) = prev_transform
5769                {
5770                    if *inserted_hunk_anchor == *prev_inserted_hunk_anchor {
5771                        panic!(
5772                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_anchor:?}. transforms: {:+?}",
5773                            self.diff_transforms.items(&()));
5774                    }
5775                }
5776                if summary.len == 0 && !self.is_empty() {
5777                    panic!("empty buffer content transform");
5778                }
5779            }
5780            prev_transform = Some(item);
5781        }
5782    }
5783}
5784
5785impl<'a, D> MultiBufferCursor<'a, D>
5786where
5787    D: TextDimension + Ord + Sub<D, Output = D>,
5788{
5789    fn seek(&mut self, position: &D) {
5790        self.cached_region.take();
5791        self.diff_transforms
5792            .seek(&OutputDimension(*position), Bias::Right, &());
5793        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5794            self.diff_transforms.prev(&());
5795        }
5796
5797        let mut excerpt_position = self.diff_transforms.start().1 .0;
5798        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5799            let overshoot = *position - self.diff_transforms.start().0 .0;
5800            excerpt_position.add_assign(&overshoot);
5801        }
5802
5803        self.excerpts
5804            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
5805        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5806            self.excerpts.prev(&());
5807        }
5808    }
5809
5810    fn seek_forward(&mut self, position: &D) {
5811        self.cached_region.take();
5812        self.diff_transforms
5813            .seek_forward(&OutputDimension(*position), Bias::Right, &());
5814        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5815            self.diff_transforms.prev(&());
5816        }
5817
5818        let overshoot = *position - self.diff_transforms.start().0 .0;
5819        let mut excerpt_position = self.diff_transforms.start().1 .0;
5820        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5821            excerpt_position.add_assign(&overshoot);
5822        }
5823
5824        self.excerpts
5825            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
5826        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5827            self.excerpts.prev(&());
5828        }
5829    }
5830
5831    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
5832        self.cached_region.take();
5833        if let Some(excerpt) = self.excerpts.item() {
5834            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
5835            let position_in_excerpt = *position - excerpt_start;
5836            let mut excerpt_position = self.excerpts.start().0;
5837            excerpt_position.add_assign(&position_in_excerpt);
5838            self.diff_transforms
5839                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
5840            if self.diff_transforms.item().is_none() {
5841                self.diff_transforms.next(&());
5842            }
5843        }
5844    }
5845
5846    fn next_excerpt(&mut self) {
5847        self.excerpts.next(&());
5848        self.seek_to_start_of_current_excerpt();
5849    }
5850
5851    fn prev_excerpt(&mut self) {
5852        self.excerpts.prev(&());
5853        self.seek_to_start_of_current_excerpt();
5854    }
5855
5856    fn seek_to_start_of_current_excerpt(&mut self) {
5857        self.cached_region.take();
5858        self.diff_transforms
5859            .seek(self.excerpts.start(), Bias::Left, &());
5860        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
5861            && self.diff_transforms.start().1 < *self.excerpts.start()
5862            && self.diff_transforms.next_item().is_some()
5863        {
5864            self.diff_transforms.next(&());
5865        }
5866    }
5867
5868    fn next(&mut self) {
5869        self.cached_region.take();
5870        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
5871            cmp::Ordering::Less => self.diff_transforms.next(&()),
5872            cmp::Ordering::Greater => self.excerpts.next(&()),
5873            cmp::Ordering::Equal => {
5874                self.diff_transforms.next(&());
5875                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
5876                    || self.diff_transforms.item().is_none()
5877                {
5878                    self.excerpts.next(&());
5879                }
5880            }
5881        }
5882    }
5883
5884    fn prev(&mut self) {
5885        self.cached_region.take();
5886        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
5887            cmp::Ordering::Less => self.excerpts.prev(&()),
5888            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
5889            cmp::Ordering::Equal => {
5890                self.diff_transforms.prev(&());
5891                if self.diff_transforms.start().1 < *self.excerpts.start()
5892                    || self.diff_transforms.item().is_none()
5893                {
5894                    self.excerpts.prev(&());
5895                }
5896            }
5897        }
5898    }
5899
5900    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
5901        if self.cached_region.is_none() {
5902            self.cached_region = self.build_region();
5903        }
5904        self.cached_region.clone()
5905    }
5906
5907    fn main_buffer_position(&self) -> Option<D> {
5908        if let DiffTransform::BufferContent { .. } = self.diff_transforms.next_item()? {
5909            let excerpt = self.excerpts.item()?;
5910            let buffer = &excerpt.buffer;
5911            let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5912            let mut buffer_start = buffer_context_start;
5913            let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
5914            buffer_start.add_assign(&overshoot);
5915            Some(buffer_start)
5916        } else {
5917            None
5918        }
5919    }
5920
5921    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
5922        let excerpt = self.excerpts.item()?;
5923        match self.diff_transforms.item()? {
5924            DiffTransform::DeletedHunk {
5925                buffer_id,
5926                base_text_byte_range,
5927                has_trailing_newline,
5928                ..
5929            } => {
5930                let diff = self.diffs.get(&buffer_id)?;
5931                let buffer = &diff.base_text;
5932                let mut rope_cursor = buffer.as_rope().cursor(0);
5933                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
5934                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
5935                let mut buffer_end = buffer_start;
5936                buffer_end.add_assign(&buffer_range_len);
5937                let start = self.diff_transforms.start().0 .0;
5938                let end = self.diff_transforms.end(&()).0 .0;
5939                return Some(MultiBufferRegion {
5940                    buffer,
5941                    excerpt,
5942                    has_trailing_newline: *has_trailing_newline,
5943                    is_main_buffer: false,
5944                    is_inserted_hunk: false,
5945                    buffer_range: buffer_start..buffer_end,
5946                    range: start..end,
5947                });
5948            }
5949            DiffTransform::BufferContent {
5950                inserted_hunk_anchor,
5951                ..
5952            } => {
5953                let buffer = &excerpt.buffer;
5954                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5955
5956                let mut start = self.diff_transforms.start().0 .0;
5957                let mut buffer_start = buffer_context_start;
5958                if self.diff_transforms.start().1 < *self.excerpts.start() {
5959                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
5960                    start.add_assign(&overshoot);
5961                } else {
5962                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
5963                    buffer_start.add_assign(&overshoot);
5964                }
5965
5966                let mut end;
5967                let mut buffer_end;
5968                let has_trailing_newline;
5969                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
5970                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
5971                    end = self.diff_transforms.end(&()).0 .0;
5972                    buffer_end = buffer_context_start;
5973                    buffer_end.add_assign(&overshoot);
5974                    has_trailing_newline = false;
5975                } else {
5976                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
5977                    end = self.diff_transforms.start().0 .0;
5978                    end.add_assign(&overshoot);
5979                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
5980                    has_trailing_newline = excerpt.has_trailing_newline;
5981                };
5982
5983                Some(MultiBufferRegion {
5984                    buffer,
5985                    excerpt,
5986                    has_trailing_newline,
5987                    is_main_buffer: true,
5988                    is_inserted_hunk: inserted_hunk_anchor.is_some(),
5989                    buffer_range: buffer_start..buffer_end,
5990                    range: start..end,
5991                })
5992            }
5993        }
5994    }
5995
5996    fn excerpt(&self) -> Option<&'a Excerpt> {
5997        self.excerpts.item()
5998    }
5999}
6000
6001impl History {
6002    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6003        self.transaction_depth += 1;
6004        if self.transaction_depth == 1 {
6005            let id = self.next_transaction_id.tick();
6006            self.undo_stack.push(Transaction {
6007                id,
6008                buffer_transactions: Default::default(),
6009                first_edit_at: now,
6010                last_edit_at: now,
6011                suppress_grouping: false,
6012            });
6013            Some(id)
6014        } else {
6015            None
6016        }
6017    }
6018
6019    fn end_transaction(
6020        &mut self,
6021        now: Instant,
6022        buffer_transactions: HashMap<BufferId, TransactionId>,
6023    ) -> bool {
6024        assert_ne!(self.transaction_depth, 0);
6025        self.transaction_depth -= 1;
6026        if self.transaction_depth == 0 {
6027            if buffer_transactions.is_empty() {
6028                self.undo_stack.pop();
6029                false
6030            } else {
6031                self.redo_stack.clear();
6032                let transaction = self.undo_stack.last_mut().unwrap();
6033                transaction.last_edit_at = now;
6034                for (buffer_id, transaction_id) in buffer_transactions {
6035                    transaction
6036                        .buffer_transactions
6037                        .entry(buffer_id)
6038                        .or_insert(transaction_id);
6039                }
6040                true
6041            }
6042        } else {
6043            false
6044        }
6045    }
6046
6047    fn push_transaction<'a, T>(
6048        &mut self,
6049        buffer_transactions: T,
6050        now: Instant,
6051        cx: &Context<MultiBuffer>,
6052    ) where
6053        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6054    {
6055        assert_eq!(self.transaction_depth, 0);
6056        let transaction = Transaction {
6057            id: self.next_transaction_id.tick(),
6058            buffer_transactions: buffer_transactions
6059                .into_iter()
6060                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6061                .collect(),
6062            first_edit_at: now,
6063            last_edit_at: now,
6064            suppress_grouping: false,
6065        };
6066        if !transaction.buffer_transactions.is_empty() {
6067            self.undo_stack.push(transaction);
6068            self.redo_stack.clear();
6069        }
6070    }
6071
6072    fn finalize_last_transaction(&mut self) {
6073        if let Some(transaction) = self.undo_stack.last_mut() {
6074            transaction.suppress_grouping = true;
6075        }
6076    }
6077
6078    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6079        if let Some(ix) = self
6080            .undo_stack
6081            .iter()
6082            .rposition(|transaction| transaction.id == transaction_id)
6083        {
6084            Some(self.undo_stack.remove(ix))
6085        } else if let Some(ix) = self
6086            .redo_stack
6087            .iter()
6088            .rposition(|transaction| transaction.id == transaction_id)
6089        {
6090            Some(self.redo_stack.remove(ix))
6091        } else {
6092            None
6093        }
6094    }
6095
6096    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6097        self.undo_stack
6098            .iter()
6099            .find(|transaction| transaction.id == transaction_id)
6100            .or_else(|| {
6101                self.redo_stack
6102                    .iter()
6103                    .find(|transaction| transaction.id == transaction_id)
6104            })
6105    }
6106
6107    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6108        self.undo_stack
6109            .iter_mut()
6110            .find(|transaction| transaction.id == transaction_id)
6111            .or_else(|| {
6112                self.redo_stack
6113                    .iter_mut()
6114                    .find(|transaction| transaction.id == transaction_id)
6115            })
6116    }
6117
6118    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6119        assert_eq!(self.transaction_depth, 0);
6120        if let Some(transaction) = self.undo_stack.pop() {
6121            self.redo_stack.push(transaction);
6122            self.redo_stack.last_mut()
6123        } else {
6124            None
6125        }
6126    }
6127
6128    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6129        assert_eq!(self.transaction_depth, 0);
6130        if let Some(transaction) = self.redo_stack.pop() {
6131            self.undo_stack.push(transaction);
6132            self.undo_stack.last_mut()
6133        } else {
6134            None
6135        }
6136    }
6137
6138    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6139        let ix = self
6140            .undo_stack
6141            .iter()
6142            .rposition(|transaction| transaction.id == transaction_id)?;
6143        let transaction = self.undo_stack.remove(ix);
6144        self.redo_stack.push(transaction);
6145        self.redo_stack.last()
6146    }
6147
6148    fn group(&mut self) -> Option<TransactionId> {
6149        let mut count = 0;
6150        let mut transactions = self.undo_stack.iter();
6151        if let Some(mut transaction) = transactions.next_back() {
6152            while let Some(prev_transaction) = transactions.next_back() {
6153                if !prev_transaction.suppress_grouping
6154                    && transaction.first_edit_at - prev_transaction.last_edit_at
6155                        <= self.group_interval
6156                {
6157                    transaction = prev_transaction;
6158                    count += 1;
6159                } else {
6160                    break;
6161                }
6162            }
6163        }
6164        self.group_trailing(count)
6165    }
6166
6167    fn group_until(&mut self, transaction_id: TransactionId) {
6168        let mut count = 0;
6169        for transaction in self.undo_stack.iter().rev() {
6170            if transaction.id == transaction_id {
6171                self.group_trailing(count);
6172                break;
6173            } else if transaction.suppress_grouping {
6174                break;
6175            } else {
6176                count += 1;
6177            }
6178        }
6179    }
6180
6181    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6182        let new_len = self.undo_stack.len() - n;
6183        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6184        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6185            if let Some(transaction) = transactions_to_merge.last() {
6186                last_transaction.last_edit_at = transaction.last_edit_at;
6187            }
6188            for to_merge in transactions_to_merge {
6189                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6190                    last_transaction
6191                        .buffer_transactions
6192                        .entry(*buffer_id)
6193                        .or_insert(*transaction_id);
6194                }
6195            }
6196        }
6197
6198        self.undo_stack.truncate(new_len);
6199        self.undo_stack.last().map(|t| t.id)
6200    }
6201}
6202
6203impl Excerpt {
6204    fn new(
6205        id: ExcerptId,
6206        locator: Locator,
6207        buffer_id: BufferId,
6208        buffer: BufferSnapshot,
6209        range: ExcerptRange<text::Anchor>,
6210        has_trailing_newline: bool,
6211    ) -> Self {
6212        Excerpt {
6213            id,
6214            locator,
6215            max_buffer_row: range.context.end.to_point(&buffer).row,
6216            text_summary: buffer
6217                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6218            buffer_id,
6219            buffer,
6220            range,
6221            has_trailing_newline,
6222        }
6223    }
6224
6225    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6226        let content_start = self.range.context.start.to_offset(&self.buffer);
6227        let chunks_start = content_start + range.start;
6228        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6229
6230        let footer_height = if self.has_trailing_newline
6231            && range.start <= self.text_summary.len
6232            && range.end > self.text_summary.len
6233        {
6234            1
6235        } else {
6236            0
6237        };
6238
6239        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6240
6241        ExcerptChunks {
6242            excerpt_id: self.id,
6243            content_chunks,
6244            footer_height,
6245        }
6246    }
6247
6248    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6249        let content_start = self.range.context.start.to_offset(&self.buffer);
6250        let chunks_start = content_start + range.start;
6251        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6252        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6253        excerpt_chunks.footer_height = if self.has_trailing_newline
6254            && range.start <= self.text_summary.len
6255            && range.end > self.text_summary.len
6256        {
6257            1
6258        } else {
6259            0
6260        };
6261    }
6262
6263    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6264        if text_anchor
6265            .cmp(&self.range.context.start, &self.buffer)
6266            .is_lt()
6267        {
6268            self.range.context.start
6269        } else if text_anchor
6270            .cmp(&self.range.context.end, &self.buffer)
6271            .is_gt()
6272        {
6273            self.range.context.end
6274        } else {
6275            text_anchor
6276        }
6277    }
6278
6279    fn contains(&self, anchor: &Anchor) -> bool {
6280        Some(self.buffer_id) == anchor.buffer_id
6281            && self
6282                .range
6283                .context
6284                .start
6285                .cmp(&anchor.text_anchor, &self.buffer)
6286                .is_le()
6287            && self
6288                .range
6289                .context
6290                .end
6291                .cmp(&anchor.text_anchor, &self.buffer)
6292                .is_ge()
6293    }
6294
6295    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6296    fn buffer_start_offset(&self) -> usize {
6297        self.range.context.start.to_offset(&self.buffer)
6298    }
6299
6300    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6301    fn buffer_end_offset(&self) -> usize {
6302        self.buffer_start_offset() + self.text_summary.len
6303    }
6304}
6305
6306impl<'a> MultiBufferExcerpt<'a> {
6307    pub fn id(&self) -> ExcerptId {
6308        self.excerpt.id
6309    }
6310
6311    pub fn buffer_id(&self) -> BufferId {
6312        self.excerpt.buffer_id
6313    }
6314
6315    pub fn start_anchor(&self) -> Anchor {
6316        Anchor {
6317            buffer_id: Some(self.excerpt.buffer_id),
6318            excerpt_id: self.excerpt.id,
6319            text_anchor: self.excerpt.range.context.start,
6320            diff_base_anchor: None,
6321        }
6322    }
6323
6324    pub fn end_anchor(&self) -> Anchor {
6325        Anchor {
6326            buffer_id: Some(self.excerpt.buffer_id),
6327            excerpt_id: self.excerpt.id,
6328            text_anchor: self.excerpt.range.context.end,
6329            diff_base_anchor: None,
6330        }
6331    }
6332
6333    pub fn buffer(&self) -> &'a BufferSnapshot {
6334        &self.excerpt.buffer
6335    }
6336
6337    pub fn buffer_range(&self) -> Range<usize> {
6338        self.buffer_offset
6339            ..self
6340                .excerpt
6341                .range
6342                .context
6343                .end
6344                .to_offset(&self.excerpt.buffer.text)
6345    }
6346
6347    pub fn start_offset(&self) -> usize {
6348        self.offset
6349    }
6350
6351    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6352    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6353        self.map_range_to_buffer(offset..offset).start
6354    }
6355
6356    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6357    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6358        self.diff_transforms
6359            .seek(&OutputDimension(range.start), Bias::Right, &());
6360        let start = self.map_offset_to_buffer_internal(range.start);
6361        let end = if range.end > range.start {
6362            self.diff_transforms
6363                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6364            self.map_offset_to_buffer_internal(range.end)
6365        } else {
6366            start
6367        };
6368        start..end
6369    }
6370
6371    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6372        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6373        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6374            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6375        };
6376        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6377        self.buffer_offset + offset_in_excerpt
6378    }
6379
6380    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6381    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6382        self.map_range_from_buffer(buffer_offset..buffer_offset)
6383            .start
6384    }
6385
6386    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6387    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6388        let overshoot = buffer_range.start - self.buffer_offset;
6389        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6390        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6391        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6392        let start = self.diff_transforms.start().0 .0 + overshoot;
6393
6394        let end = if buffer_range.end > buffer_range.start {
6395            let overshoot = buffer_range.end - self.buffer_offset;
6396            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6397            self.diff_transforms
6398                .seek_forward(&excerpt_offset, Bias::Right, &());
6399            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6400            self.diff_transforms.start().0 .0 + overshoot
6401        } else {
6402            start
6403        };
6404
6405        start..end
6406    }
6407
6408    /// Returns true if the entirety of the given range is in the buffer's excerpt
6409    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6410        range.start >= self.excerpt.buffer_start_offset()
6411            && range.end <= self.excerpt.buffer_end_offset()
6412    }
6413
6414    pub fn max_buffer_row(&self) -> u32 {
6415        self.excerpt.max_buffer_row
6416    }
6417}
6418
6419impl ExcerptId {
6420    pub fn min() -> Self {
6421        Self(0)
6422    }
6423
6424    pub fn max() -> Self {
6425        Self(usize::MAX)
6426    }
6427
6428    pub fn to_proto(&self) -> u64 {
6429        self.0 as _
6430    }
6431
6432    pub fn from_proto(proto: u64) -> Self {
6433        Self(proto as _)
6434    }
6435
6436    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6437        let a = snapshot.excerpt_locator_for_id(*self);
6438        let b = snapshot.excerpt_locator_for_id(*other);
6439        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6440    }
6441}
6442
6443impl From<ExcerptId> for usize {
6444    fn from(val: ExcerptId) -> Self {
6445        val.0
6446    }
6447}
6448
6449impl fmt::Debug for Excerpt {
6450    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6451        f.debug_struct("Excerpt")
6452            .field("id", &self.id)
6453            .field("locator", &self.locator)
6454            .field("buffer_id", &self.buffer_id)
6455            .field("range", &self.range)
6456            .field("text_summary", &self.text_summary)
6457            .field("has_trailing_newline", &self.has_trailing_newline)
6458            .finish()
6459    }
6460}
6461
6462impl sum_tree::Item for Excerpt {
6463    type Summary = ExcerptSummary;
6464
6465    fn summary(&self, _cx: &()) -> Self::Summary {
6466        let mut text = self.text_summary;
6467        if self.has_trailing_newline {
6468            text += TextSummary::from("\n");
6469        }
6470        ExcerptSummary {
6471            excerpt_id: self.id,
6472            excerpt_locator: self.locator.clone(),
6473            widest_line_number: self.max_buffer_row,
6474            text,
6475        }
6476    }
6477}
6478
6479impl sum_tree::Item for ExcerptIdMapping {
6480    type Summary = ExcerptId;
6481
6482    fn summary(&self, _cx: &()) -> Self::Summary {
6483        self.id
6484    }
6485}
6486
6487impl sum_tree::KeyedItem for ExcerptIdMapping {
6488    type Key = ExcerptId;
6489
6490    fn key(&self) -> Self::Key {
6491        self.id
6492    }
6493}
6494
6495impl DiffTransform {
6496    fn hunk_anchor(&self) -> Option<(ExcerptId, text::Anchor)> {
6497        match self {
6498            DiffTransform::DeletedHunk { hunk_anchor, .. } => Some(*hunk_anchor),
6499            DiffTransform::BufferContent {
6500                inserted_hunk_anchor,
6501                ..
6502            } => *inserted_hunk_anchor,
6503        }
6504    }
6505}
6506
6507impl sum_tree::Item for DiffTransform {
6508    type Summary = DiffTransformSummary;
6509
6510    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6511        match self {
6512            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6513                input: *summary,
6514                output: *summary,
6515            },
6516            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6517                input: TextSummary::default(),
6518                output: *summary,
6519            },
6520        }
6521    }
6522}
6523
6524impl DiffTransformSummary {
6525    fn excerpt_len(&self) -> ExcerptOffset {
6526        ExcerptOffset::new(self.input.len)
6527    }
6528}
6529
6530impl sum_tree::Summary for DiffTransformSummary {
6531    type Context = ();
6532
6533    fn zero(_: &Self::Context) -> Self {
6534        DiffTransformSummary {
6535            input: TextSummary::default(),
6536            output: TextSummary::default(),
6537        }
6538    }
6539
6540    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6541        self.input += &summary.input;
6542        self.output += &summary.output;
6543    }
6544}
6545
6546impl sum_tree::Summary for ExcerptId {
6547    type Context = ();
6548
6549    fn zero(_cx: &()) -> Self {
6550        Default::default()
6551    }
6552
6553    fn add_summary(&mut self, other: &Self, _: &()) {
6554        *self = *other;
6555    }
6556}
6557
6558impl sum_tree::Summary for ExcerptSummary {
6559    type Context = ();
6560
6561    fn zero(_cx: &()) -> Self {
6562        Default::default()
6563    }
6564
6565    fn add_summary(&mut self, summary: &Self, _: &()) {
6566        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6567        self.excerpt_locator = summary.excerpt_locator.clone();
6568        self.text.add_summary(&summary.text, &());
6569        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6570    }
6571}
6572
6573impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6574    fn zero(_cx: &()) -> Self {
6575        Default::default()
6576    }
6577
6578    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6579        self.value += summary.text.len;
6580    }
6581}
6582
6583impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6584    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6585        Ord::cmp(&self.value, &cursor_location.text.len)
6586    }
6587}
6588
6589impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6590    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6591        Ord::cmp(&Some(self), cursor_location)
6592    }
6593}
6594
6595impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
6596    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6597        Ord::cmp(self, &cursor_location.excerpt_locator)
6598    }
6599}
6600
6601impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6602    fn zero(_cx: &()) -> Self {
6603        Default::default()
6604    }
6605
6606    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6607        self.value += summary.text.lines;
6608    }
6609}
6610
6611impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6612    for ExcerptDimension<D>
6613{
6614    fn zero(_: &()) -> Self {
6615        ExcerptDimension(D::default())
6616    }
6617
6618    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6619        self.0.add_assign(&D::from_text_summary(&summary.text))
6620    }
6621}
6622
6623impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6624    fn zero(_cx: &()) -> Self {
6625        Default::default()
6626    }
6627
6628    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6629        *self = Some(&summary.excerpt_locator);
6630    }
6631}
6632
6633impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6634    fn zero(_cx: &()) -> Self {
6635        Default::default()
6636    }
6637
6638    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6639        *self = Some(summary.excerpt_id);
6640    }
6641}
6642
6643#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6644struct ExcerptDimension<T>(T);
6645
6646#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6647struct OutputDimension<T>(T);
6648
6649impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6650    fn zero(_: &()) -> Self {
6651        ExcerptOffset::new(0)
6652    }
6653
6654    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6655        self.value += summary.input.len;
6656    }
6657}
6658
6659impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6660    fn zero(_: &()) -> Self {
6661        ExcerptPoint::new(0, 0)
6662    }
6663
6664    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6665        self.value += summary.input.lines;
6666    }
6667}
6668
6669impl<'a, D: TextDimension + Ord>
6670    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransformSummary> for ExcerptDimension<D>
6671{
6672    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6673        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6674    }
6675}
6676
6677impl<'a, D: TextDimension + Ord>
6678    sum_tree::SeekTarget<'a, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6679    for ExcerptDimension<D>
6680{
6681    fn cmp(
6682        &self,
6683        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6684        _: &(),
6685    ) -> cmp::Ordering {
6686        Ord::cmp(&self.0, &cursor_location.1 .0)
6687    }
6688}
6689
6690impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6691    fn zero(_: &()) -> Self {
6692        ExcerptDimension(D::default())
6693    }
6694
6695    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6696        self.0.add_assign(&D::from_text_summary(&summary.input))
6697    }
6698}
6699
6700impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6701    fn zero(_: &()) -> Self {
6702        OutputDimension(D::default())
6703    }
6704
6705    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6706        self.0.add_assign(&D::from_text_summary(&summary.output))
6707    }
6708}
6709
6710impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6711    fn zero(_: &()) -> Self {
6712        TextSummary::default()
6713    }
6714
6715    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6716        *self += summary.output
6717    }
6718}
6719
6720impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6721    fn zero(_: &()) -> Self {
6722        0
6723    }
6724
6725    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6726        *self += summary.output.len
6727    }
6728}
6729
6730impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6731    fn zero(_: &()) -> Self {
6732        Point::new(0, 0)
6733    }
6734
6735    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6736        *self += summary.output.lines
6737    }
6738}
6739
6740impl<'a> MultiBufferRows<'a> {
6741    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6742        self.point = Point::new(row, 0);
6743        self.cursor.seek(&self.point);
6744    }
6745}
6746
6747impl<'a> Iterator for MultiBufferRows<'a> {
6748    type Item = RowInfo;
6749
6750    fn next(&mut self) -> Option<Self::Item> {
6751        if self.is_empty && self.point.row == 0 {
6752            self.point += Point::new(1, 0);
6753            return Some(RowInfo {
6754                buffer_row: Some(0),
6755                multibuffer_row: Some(MultiBufferRow(0)),
6756                diff_status: None,
6757            });
6758        }
6759
6760        let mut region = self.cursor.region()?;
6761        while self.point >= region.range.end {
6762            self.cursor.next();
6763            if let Some(next_region) = self.cursor.region() {
6764                region = next_region;
6765            } else {
6766                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
6767                    let multibuffer_row = MultiBufferRow(self.point.row);
6768                    self.point += Point::new(1, 0);
6769                    let last_excerpt = self
6770                        .cursor
6771                        .excerpts
6772                        .item()
6773                        .or(self.cursor.excerpts.prev_item())?;
6774                    let last_row = last_excerpt
6775                        .range
6776                        .context
6777                        .end
6778                        .to_point(&last_excerpt.buffer)
6779                        .row;
6780                    return Some(RowInfo {
6781                        buffer_row: Some(last_row),
6782                        multibuffer_row: Some(multibuffer_row),
6783                        diff_status: None,
6784                    });
6785                } else {
6786                    return None;
6787                }
6788            };
6789        }
6790
6791        let overshoot = self.point - region.range.start;
6792        let buffer_point = region.buffer_range.start + overshoot;
6793        let result = Some(RowInfo {
6794            buffer_row: Some(buffer_point.row),
6795            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6796            diff_status: if region.is_inserted_hunk && self.point < region.range.end {
6797                Some(DiffHunkStatus::Added)
6798            } else if !region.is_main_buffer {
6799                Some(DiffHunkStatus::Removed)
6800            } else {
6801                None
6802            },
6803        });
6804        self.point += Point::new(1, 0);
6805        result
6806    }
6807}
6808
6809impl<'a> MultiBufferChunks<'a> {
6810    pub fn offset(&self) -> usize {
6811        self.range.start
6812    }
6813
6814    pub fn seek(&mut self, range: Range<usize>) {
6815        self.diff_transforms.seek(&range.end, Bias::Right, &());
6816        let mut excerpt_end = self.diff_transforms.start().1;
6817        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6818            let overshoot = range.end - self.diff_transforms.start().0;
6819            excerpt_end.value += overshoot;
6820        }
6821
6822        self.diff_transforms.seek(&range.start, Bias::Right, &());
6823        let mut excerpt_start = self.diff_transforms.start().1;
6824        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6825            let overshoot = range.start - self.diff_transforms.start().0;
6826            excerpt_start.value += overshoot;
6827        }
6828
6829        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6830        self.buffer_chunk.take();
6831        self.range = range;
6832    }
6833
6834    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6835        self.excerpt_offset_range = new_range.clone();
6836        self.excerpts.seek(&new_range.start, Bias::Right, &());
6837        if let Some(excerpt) = self.excerpts.item() {
6838            let excerpt_start = *self.excerpts.start();
6839            if let Some(excerpt_chunks) = self
6840                .excerpt_chunks
6841                .as_mut()
6842                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6843            {
6844                excerpt.seek_chunks(
6845                    excerpt_chunks,
6846                    (self.excerpt_offset_range.start - excerpt_start).value
6847                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6848                );
6849            } else {
6850                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6851                    (self.excerpt_offset_range.start - excerpt_start).value
6852                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6853                    self.language_aware,
6854                ));
6855            }
6856        } else {
6857            self.excerpt_chunks = None;
6858        }
6859    }
6860
6861    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6862        loop {
6863            if self.excerpt_offset_range.is_empty() {
6864                return None;
6865            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6866                self.excerpt_offset_range.start.value += chunk.text.len();
6867                return Some(chunk);
6868            } else {
6869                self.excerpts.next(&());
6870                let excerpt = self.excerpts.item()?;
6871                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6872                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6873                    self.language_aware,
6874                ));
6875            }
6876        }
6877    }
6878}
6879
6880impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6881    type Item = &'a str;
6882
6883    fn next(&mut self) -> Option<Self::Item> {
6884        let mut region = self.cursor.region()?;
6885        if self.offset == region.range.start {
6886            self.cursor.prev();
6887            region = self.cursor.region()?;
6888            let start_overshoot = self.start.saturating_sub(region.range.start);
6889            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6890                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6891            ));
6892        }
6893
6894        if self.offset == region.range.end && region.has_trailing_newline {
6895            self.offset -= 1;
6896            Some("\n")
6897        } else {
6898            let chunk = self.current_chunks.as_mut().unwrap().next().unwrap();
6899            self.offset -= chunk.len();
6900            Some(chunk)
6901        }
6902    }
6903}
6904
6905impl<'a> Iterator for MultiBufferChunks<'a> {
6906    type Item = Chunk<'a>;
6907
6908    fn next(&mut self) -> Option<Chunk<'a>> {
6909        if self.range.start >= self.range.end {
6910            return None;
6911        }
6912        if self.range.start == self.diff_transforms.end(&()).0 {
6913            self.diff_transforms.next(&());
6914        }
6915
6916        let diff_transform_start = self.diff_transforms.start().0;
6917        let diff_transform_end = self.diff_transforms.end(&()).0;
6918        debug_assert!(self.range.start < diff_transform_end);
6919
6920        let diff_transform = self.diff_transforms.item()?;
6921        match diff_transform {
6922            DiffTransform::BufferContent { .. } => {
6923                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6924                    chunk
6925                } else {
6926                    let chunk = self.next_excerpt_chunk().unwrap();
6927                    self.buffer_chunk.insert(chunk)
6928                };
6929
6930                let chunk_end = self.range.start + chunk.text.len();
6931                let diff_transform_end = diff_transform_end.min(self.range.end);
6932
6933                if diff_transform_end < chunk_end {
6934                    let (before, after) =
6935                        chunk.text.split_at(diff_transform_end - self.range.start);
6936                    self.range.start = diff_transform_end;
6937                    chunk.text = after;
6938                    Some(Chunk {
6939                        text: before,
6940                        ..chunk.clone()
6941                    })
6942                } else {
6943                    self.range.start = chunk_end;
6944                    self.buffer_chunk.take()
6945                }
6946            }
6947            DiffTransform::DeletedHunk {
6948                buffer_id,
6949                base_text_byte_range,
6950                has_trailing_newline,
6951                ..
6952            } => {
6953                let base_text_start =
6954                    base_text_byte_range.start + self.range.start - diff_transform_start;
6955                let base_text_end =
6956                    base_text_byte_range.start + self.range.end - diff_transform_start;
6957                let base_text_end = base_text_end.min(base_text_byte_range.end);
6958
6959                let mut chunks = if let Some((_, mut chunks)) = self
6960                    .diff_base_chunks
6961                    .take()
6962                    .filter(|(id, _)| id == buffer_id)
6963                {
6964                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
6965                    {
6966                        chunks.seek(base_text_start..base_text_end);
6967                    }
6968                    chunks
6969                } else {
6970                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text;
6971                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
6972                };
6973
6974                let chunk = if let Some(chunk) = chunks.next() {
6975                    self.range.start += chunk.text.len();
6976                    self.diff_base_chunks = Some((*buffer_id, chunks));
6977                    chunk
6978                } else {
6979                    debug_assert!(has_trailing_newline);
6980                    self.range.start += "\n".len();
6981                    Chunk {
6982                        text: "\n",
6983                        ..Default::default()
6984                    }
6985                };
6986                Some(chunk)
6987            }
6988        }
6989    }
6990}
6991
6992impl<'a> MultiBufferBytes<'a> {
6993    fn consume(&mut self, len: usize) {
6994        self.range.start += len;
6995        self.chunk = &self.chunk[len..];
6996
6997        if !self.range.is_empty() && self.chunk.is_empty() {
6998            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
6999                self.chunk = chunk;
7000            } else if self.has_trailing_newline {
7001                self.has_trailing_newline = false;
7002                self.chunk = b"\n";
7003            } else {
7004                self.cursor.next();
7005                if let Some(region) = self.cursor.region() {
7006                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7007                        region.buffer_range.start
7008                            ..(region.buffer_range.start + self.range.end - region.range.start)
7009                                .min(region.buffer_range.end),
7010                    );
7011                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7012                    self.excerpt_bytes = Some(excerpt_bytes);
7013                    self.has_trailing_newline =
7014                        region.has_trailing_newline && self.range.end >= region.range.end;
7015                    if self.chunk.is_empty() && self.has_trailing_newline {
7016                        self.has_trailing_newline = false;
7017                        self.chunk = b"\n";
7018                    }
7019                }
7020            }
7021        }
7022    }
7023}
7024
7025impl<'a> Iterator for MultiBufferBytes<'a> {
7026    type Item = &'a [u8];
7027
7028    fn next(&mut self) -> Option<Self::Item> {
7029        let chunk = self.chunk;
7030        if chunk.is_empty() {
7031            None
7032        } else {
7033            self.consume(chunk.len());
7034            Some(chunk)
7035        }
7036    }
7037}
7038
7039impl<'a> io::Read for MultiBufferBytes<'a> {
7040    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7041        let len = cmp::min(buf.len(), self.chunk.len());
7042        buf[..len].copy_from_slice(&self.chunk[..len]);
7043        if len > 0 {
7044            self.consume(len);
7045        }
7046        Ok(len)
7047    }
7048}
7049
7050impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
7051    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7052        let len = cmp::min(buf.len(), self.chunk.len());
7053        buf[..len].copy_from_slice(&self.chunk[..len]);
7054        buf[..len].reverse();
7055        if len > 0 {
7056            self.range.end -= len;
7057            self.chunk = &self.chunk[..self.chunk.len() - len];
7058            if !self.range.is_empty() && self.chunk.is_empty() {
7059                if let Some(chunk) = self.chunks.next() {
7060                    self.chunk = chunk.as_bytes();
7061                }
7062            }
7063        }
7064        Ok(len)
7065    }
7066}
7067
7068impl<'a> Iterator for ExcerptChunks<'a> {
7069    type Item = Chunk<'a>;
7070
7071    fn next(&mut self) -> Option<Self::Item> {
7072        if let Some(chunk) = self.content_chunks.next() {
7073            return Some(chunk);
7074        }
7075
7076        if self.footer_height > 0 {
7077            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7078            self.footer_height = 0;
7079            return Some(Chunk {
7080                text,
7081                ..Default::default()
7082            });
7083        }
7084
7085        None
7086    }
7087}
7088
7089impl ToOffset for Point {
7090    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7091        snapshot.point_to_offset(*self)
7092    }
7093}
7094
7095impl ToOffset for usize {
7096    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7097        assert!(*self <= snapshot.len(), "offset is out of range");
7098        *self
7099    }
7100}
7101
7102impl ToOffset for OffsetUtf16 {
7103    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7104        snapshot.offset_utf16_to_offset(*self)
7105    }
7106}
7107
7108impl ToOffset for PointUtf16 {
7109    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7110        snapshot.point_utf16_to_offset(*self)
7111    }
7112}
7113
7114impl ToOffsetUtf16 for OffsetUtf16 {
7115    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7116        *self
7117    }
7118}
7119
7120impl ToOffsetUtf16 for usize {
7121    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7122        snapshot.offset_to_offset_utf16(*self)
7123    }
7124}
7125
7126impl ToPoint for usize {
7127    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7128        snapshot.offset_to_point(*self)
7129    }
7130}
7131
7132impl ToPoint for Point {
7133    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7134        *self
7135    }
7136}
7137
7138impl ToPointUtf16 for usize {
7139    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7140        snapshot.offset_to_point_utf16(*self)
7141    }
7142}
7143
7144impl ToPointUtf16 for Point {
7145    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7146        snapshot.point_to_point_utf16(*self)
7147    }
7148}
7149
7150impl ToPointUtf16 for PointUtf16 {
7151    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7152        *self
7153    }
7154}
7155
7156impl From<ExcerptId> for EntityId {
7157    fn from(id: ExcerptId) -> Self {
7158        EntityId::from(id.0 as u64)
7159    }
7160}
7161
7162pub fn build_excerpt_ranges<T>(
7163    buffer: &BufferSnapshot,
7164    ranges: &[Range<T>],
7165    context_line_count: u32,
7166) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7167where
7168    T: text::ToPoint,
7169{
7170    let max_point = buffer.max_point();
7171    let mut range_counts = Vec::new();
7172    let mut excerpt_ranges = Vec::new();
7173    let mut range_iter = ranges
7174        .iter()
7175        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7176        .peekable();
7177    while let Some(range) = range_iter.next() {
7178        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7179        let row = (range.end.row + context_line_count).min(max_point.row);
7180        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7181
7182        let mut ranges_in_excerpt = 1;
7183
7184        while let Some(next_range) = range_iter.peek() {
7185            if next_range.start.row <= excerpt_end.row + context_line_count {
7186                let row = (next_range.end.row + context_line_count).min(max_point.row);
7187                excerpt_end = Point::new(row, buffer.line_len(row));
7188
7189                ranges_in_excerpt += 1;
7190                range_iter.next();
7191            } else {
7192                break;
7193            }
7194        }
7195
7196        excerpt_ranges.push(ExcerptRange {
7197            context: excerpt_start..excerpt_end,
7198            primary: Some(range),
7199        });
7200        range_counts.push(ranges_in_excerpt);
7201    }
7202
7203    (excerpt_ranges, range_counts)
7204}