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 range = range.to_point(&snapshot);
2257
2258            let mut start = snapshot.anchor_before(Point::new(range.start.row, 0));
2259            let mut end = snapshot.anchor_before(Point::new(
2260                range.end.row,
2261                snapshot.line_len(MultiBufferRow(range.end.row)),
2262            ));
2263            let peek_end = if range.end.row < snapshot.max_row().0 {
2264                Point::new(range.end.row + 1, 0)
2265            } else {
2266                range.end
2267            };
2268
2269            for diff_hunk in snapshot.diff_hunks_in_range(range.start..peek_end) {
2270                if diff_hunk.row_range.start.0 <= range.start.row
2271                    && diff_hunk.row_range.end.0 >= range.start.row
2272                    && diff_hunk.excerpt_id == start.excerpt_id
2273                {
2274                    start = Anchor::in_buffer(
2275                        diff_hunk.excerpt_id,
2276                        diff_hunk.buffer_id,
2277                        diff_hunk.buffer_range.start,
2278                    );
2279                }
2280                if diff_hunk.row_range.start.0 <= peek_end.row
2281                    && diff_hunk.excerpt_id == end.excerpt_id
2282                {
2283                    end = Anchor::in_buffer(
2284                        diff_hunk.excerpt_id,
2285                        diff_hunk.buffer_id,
2286                        diff_hunk.buffer_range.end,
2287                    );
2288                }
2289            }
2290            let start = snapshot.excerpt_offset_for_anchor(&start);
2291            let end = snapshot.excerpt_offset_for_anchor(&end);
2292            excerpt_edits.push(text::Edit {
2293                old: start..end,
2294                new: start..end,
2295            });
2296        }
2297
2298        self.sync_diff_transforms(
2299            snapshot,
2300            excerpt_edits,
2301            DiffChangeKind::ExpandOrCollapseHunks { expand },
2302        );
2303        cx.emit(Event::DiffHunksToggled);
2304        cx.emit(Event::Edited {
2305            singleton_buffer_edited: false,
2306            edited_buffer: None,
2307        });
2308    }
2309
2310    pub fn resize_excerpt(
2311        &mut self,
2312        id: ExcerptId,
2313        range: Range<text::Anchor>,
2314        cx: &mut Context<Self>,
2315    ) {
2316        self.sync(cx);
2317
2318        let mut snapshot = self.snapshot.borrow_mut();
2319        let locator = snapshot.excerpt_locator_for_id(id);
2320        let mut new_excerpts = SumTree::default();
2321        let mut cursor = snapshot
2322            .excerpts
2323            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2324        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2325
2326        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2327        new_excerpts.append(prefix, &());
2328
2329        let mut excerpt = cursor.item().unwrap().clone();
2330        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2331
2332        excerpt.range.context.start = range.start;
2333        excerpt.range.context.end = range.end;
2334        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2335
2336        excerpt.text_summary = excerpt
2337            .buffer
2338            .text_summary_for_range(excerpt.range.context.clone());
2339
2340        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2341        let old_start_offset = cursor.start().1;
2342        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2343        let edit = Edit {
2344            old: old_start_offset..old_start_offset + old_text_len,
2345            new: new_start_offset..new_start_offset + new_text_len,
2346        };
2347
2348        if let Some(last_edit) = edits.last_mut() {
2349            if last_edit.old.end == edit.old.start {
2350                last_edit.old.end = edit.old.end;
2351                last_edit.new.end = edit.new.end;
2352            } else {
2353                edits.push(edit);
2354            }
2355        } else {
2356            edits.push(edit);
2357        }
2358
2359        new_excerpts.push(excerpt, &());
2360
2361        cursor.next(&());
2362
2363        new_excerpts.append(cursor.suffix(&()), &());
2364
2365        drop(cursor);
2366        snapshot.excerpts = new_excerpts;
2367
2368        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
2369        cx.emit(Event::Edited {
2370            singleton_buffer_edited: false,
2371            edited_buffer: None,
2372        });
2373        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2374        cx.notify();
2375    }
2376
2377    pub fn expand_excerpts(
2378        &mut self,
2379        ids: impl IntoIterator<Item = ExcerptId>,
2380        line_count: u32,
2381        direction: ExpandExcerptDirection,
2382        cx: &mut Context<Self>,
2383    ) {
2384        if line_count == 0 {
2385            return;
2386        }
2387        self.sync(cx);
2388        let mut snapshot = self.snapshot.borrow_mut();
2389
2390        let ids = ids.into_iter().collect::<Vec<_>>();
2391        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2392        let mut new_excerpts = SumTree::default();
2393        let mut cursor = snapshot
2394            .excerpts
2395            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2396        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2397
2398        for locator in &locators {
2399            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2400            new_excerpts.append(prefix, &());
2401
2402            let mut excerpt = cursor.item().unwrap().clone();
2403            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2404
2405            let up_line_count = if direction.should_expand_up() {
2406                line_count
2407            } else {
2408                0
2409            };
2410
2411            let start_row = excerpt
2412                .range
2413                .context
2414                .start
2415                .to_point(&excerpt.buffer)
2416                .row
2417                .saturating_sub(up_line_count);
2418            let start_point = Point::new(start_row, 0);
2419            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2420
2421            let down_line_count = if direction.should_expand_down() {
2422                line_count
2423            } else {
2424                0
2425            };
2426
2427            let mut end_point = excerpt.buffer.clip_point(
2428                excerpt.range.context.end.to_point(&excerpt.buffer)
2429                    + Point::new(down_line_count, 0),
2430                Bias::Left,
2431            );
2432            end_point.column = excerpt.buffer.line_len(end_point.row);
2433            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2434            excerpt.max_buffer_row = end_point.row;
2435
2436            excerpt.text_summary = excerpt
2437                .buffer
2438                .text_summary_for_range(excerpt.range.context.clone());
2439
2440            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2441            let old_start_offset = cursor.start().1;
2442            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2443            let edit = Edit {
2444                old: old_start_offset..old_start_offset + old_text_len,
2445                new: new_start_offset..new_start_offset + new_text_len,
2446            };
2447
2448            if let Some(last_edit) = edits.last_mut() {
2449                if last_edit.old.end == edit.old.start {
2450                    last_edit.old.end = edit.old.end;
2451                    last_edit.new.end = edit.new.end;
2452                } else {
2453                    edits.push(edit);
2454                }
2455            } else {
2456                edits.push(edit);
2457            }
2458
2459            new_excerpts.push(excerpt, &());
2460
2461            cursor.next(&());
2462        }
2463
2464        new_excerpts.append(cursor.suffix(&()), &());
2465
2466        drop(cursor);
2467        snapshot.excerpts = new_excerpts;
2468
2469        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
2470        cx.emit(Event::Edited {
2471            singleton_buffer_edited: false,
2472            edited_buffer: None,
2473        });
2474        cx.emit(Event::ExcerptsExpanded { ids });
2475        cx.notify();
2476    }
2477
2478    fn sync(&self, cx: &App) {
2479        let mut snapshot = self.snapshot.borrow_mut();
2480        let mut excerpts_to_edit = Vec::new();
2481        let mut non_text_state_updated = false;
2482        let mut is_dirty = false;
2483        let mut has_deleted_file = false;
2484        let mut has_conflict = false;
2485        let mut edited = false;
2486        let mut buffers = self.buffers.borrow_mut();
2487        for buffer_state in buffers.values_mut() {
2488            let buffer = buffer_state.buffer.read(cx);
2489            let version = buffer.version();
2490            let non_text_state_update_count = buffer.non_text_state_update_count();
2491
2492            let buffer_edited = version.changed_since(&buffer_state.last_version);
2493            let buffer_non_text_state_updated =
2494                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2495            if buffer_edited || buffer_non_text_state_updated {
2496                buffer_state.last_version = version;
2497                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2498                excerpts_to_edit.extend(
2499                    buffer_state
2500                        .excerpts
2501                        .iter()
2502                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2503                );
2504            }
2505
2506            edited |= buffer_edited;
2507            non_text_state_updated |= buffer_non_text_state_updated;
2508            is_dirty |= buffer.is_dirty();
2509            has_deleted_file |= buffer
2510                .file()
2511                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2512            has_conflict |= buffer.has_conflict();
2513        }
2514        if edited {
2515            snapshot.edit_count += 1;
2516        }
2517        if non_text_state_updated {
2518            snapshot.non_text_state_update_count += 1;
2519        }
2520        snapshot.is_dirty = is_dirty;
2521        snapshot.has_deleted_file = has_deleted_file;
2522        snapshot.has_conflict = has_conflict;
2523
2524        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2525
2526        let mut edits = Vec::new();
2527        let mut new_excerpts = SumTree::default();
2528        let mut cursor = snapshot
2529            .excerpts
2530            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2531
2532        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2533            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2534            let old_excerpt = cursor.item().unwrap();
2535            let buffer = buffer.read(cx);
2536            let buffer_id = buffer.remote_id();
2537
2538            let mut new_excerpt;
2539            if buffer_edited {
2540                edits.extend(
2541                    buffer
2542                        .edits_since_in_range::<usize>(
2543                            old_excerpt.buffer.version(),
2544                            old_excerpt.range.context.clone(),
2545                        )
2546                        .map(|edit| {
2547                            let excerpt_old_start = cursor.start().1;
2548                            let excerpt_new_start =
2549                                ExcerptOffset::new(new_excerpts.summary().text.len);
2550                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2551                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2552                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2553                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2554                            Edit {
2555                                old: old_start..old_end,
2556                                new: new_start..new_end,
2557                            }
2558                        }),
2559                );
2560
2561                new_excerpt = Excerpt::new(
2562                    old_excerpt.id,
2563                    locator.clone(),
2564                    buffer_id,
2565                    buffer.snapshot(),
2566                    old_excerpt.range.clone(),
2567                    old_excerpt.has_trailing_newline,
2568                );
2569            } else {
2570                new_excerpt = old_excerpt.clone();
2571                new_excerpt.buffer = buffer.snapshot();
2572            }
2573
2574            new_excerpts.push(new_excerpt, &());
2575            cursor.next(&());
2576        }
2577        new_excerpts.append(cursor.suffix(&()), &());
2578
2579        drop(cursor);
2580        snapshot.excerpts = new_excerpts;
2581
2582        self.sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited);
2583    }
2584
2585    fn sync_diff_transforms(
2586        &self,
2587        mut snapshot: RefMut<MultiBufferSnapshot>,
2588        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2589        change_kind: DiffChangeKind,
2590    ) {
2591        if excerpt_edits.is_empty() {
2592            return;
2593        }
2594
2595        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2596        let mut old_diff_transforms = snapshot
2597            .diff_transforms
2598            .cursor::<(ExcerptOffset, usize)>(&());
2599        let mut new_diff_transforms = SumTree::default();
2600        let mut old_expanded_hunks = HashSet::default();
2601        let mut output_edits = Vec::new();
2602        let mut output_delta = 0_isize;
2603        let mut at_transform_boundary = true;
2604        let mut end_of_current_insert = None;
2605
2606        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2607        while let Some(edit) = excerpt_edits.next() {
2608            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2609            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2610                excerpts.prev(&());
2611            }
2612
2613            // Keep any transforms that are before the edit.
2614            if at_transform_boundary {
2615                at_transform_boundary = false;
2616                let transforms_before_edit =
2617                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2618                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2619                if let Some(transform) = old_diff_transforms.item() {
2620                    if old_diff_transforms.end(&()).0 == edit.old.start
2621                        && old_diff_transforms.start().0 < edit.old.start
2622                    {
2623                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2624                        old_diff_transforms.next(&());
2625                    }
2626                }
2627            }
2628
2629            // Compute the start of the edit in output coordinates.
2630            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2631            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2632            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2633
2634            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2635                &edit,
2636                &mut excerpts,
2637                &mut old_diff_transforms,
2638                &mut new_diff_transforms,
2639                &mut end_of_current_insert,
2640                &mut old_expanded_hunks,
2641                &snapshot,
2642                change_kind,
2643            );
2644
2645            // Compute the end of the edit in output coordinates.
2646            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2647            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2648            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2649            let edit_new_end =
2650                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2651            let output_edit = Edit {
2652                old: edit_old_start..edit_old_end,
2653                new: edit_new_start..edit_new_end,
2654            };
2655
2656            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2657            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2658            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2659                output_edits.push(output_edit);
2660            }
2661
2662            // If this is the last edit that intersects the current diff transform,
2663            // then recreate the content up to the end of this transform, to prepare
2664            // for reusing additional slices of the old transforms.
2665            if excerpt_edits.peek().map_or(true, |next_edit| {
2666                next_edit.old.start >= old_diff_transforms.end(&()).0
2667            }) {
2668                let mut excerpt_offset = edit.new.end;
2669                if old_diff_transforms.start().0 < edit.old.end {
2670                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2671                    old_diff_transforms.next(&());
2672                }
2673                old_expanded_hunks.clear();
2674                self.push_buffer_content_transform(
2675                    &snapshot,
2676                    &mut new_diff_transforms,
2677                    excerpt_offset,
2678                    end_of_current_insert,
2679                );
2680                at_transform_boundary = true;
2681            }
2682        }
2683
2684        // Keep any transforms that are after the last edit.
2685        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2686
2687        // Ensure there's always at least one buffer content transform.
2688        if new_diff_transforms.is_empty() {
2689            new_diff_transforms.push(
2690                DiffTransform::BufferContent {
2691                    summary: Default::default(),
2692                    inserted_hunk_anchor: None,
2693                },
2694                &(),
2695            );
2696        }
2697
2698        self.subscriptions.publish(output_edits);
2699        drop(old_diff_transforms);
2700        drop(excerpts);
2701        snapshot.diff_transforms = new_diff_transforms;
2702        snapshot.edit_count += 1;
2703
2704        #[cfg(any(test, feature = "test-support"))]
2705        snapshot.check_invariants();
2706    }
2707
2708    #[allow(clippy::too_many_arguments)]
2709    fn recompute_diff_transforms_for_edit(
2710        &self,
2711        edit: &Edit<TypedOffset<Excerpt>>,
2712        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2713        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2714        new_diff_transforms: &mut SumTree<DiffTransform>,
2715        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, ExcerptId, text::Anchor)>,
2716        old_expanded_hunks: &mut HashSet<(ExcerptId, text::Anchor)>,
2717        snapshot: &MultiBufferSnapshot,
2718        change_kind: DiffChangeKind,
2719    ) -> bool {
2720        log::trace!(
2721            "recomputing diff transform for edit {:?} => {:?}",
2722            edit.old.start.value..edit.old.end.value,
2723            edit.new.start.value..edit.new.end.value
2724        );
2725
2726        // Record which hunks were previously expanded.
2727        while let Some(item) = old_diff_transforms.item() {
2728            if let Some(hunk_anchor) = item.hunk_anchor() {
2729                log::trace!(
2730                    "previously expanded hunk at {}",
2731                    old_diff_transforms.start().0
2732                );
2733                old_expanded_hunks.insert(hunk_anchor);
2734            }
2735            if old_diff_transforms.end(&()).0 > edit.old.end {
2736                break;
2737            }
2738            old_diff_transforms.next(&());
2739        }
2740
2741        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2742        if old_expanded_hunks.is_empty()
2743            && change_kind == DiffChangeKind::BufferEdited
2744            && !self.all_diff_hunks_expanded
2745        {
2746            return false;
2747        }
2748
2749        // Visit each excerpt that intersects the edit.
2750        let mut did_expand_hunks = false;
2751        while let Some(excerpt) = excerpts.item() {
2752            if excerpt.text_summary.len == 0 {
2753                if excerpts.end(&()) <= edit.new.end {
2754                    excerpts.next(&());
2755                    continue;
2756                } else {
2757                    break;
2758                }
2759            }
2760
2761            // Recompute the expanded hunks in the portion of the excerpt that
2762            // intersects the edit.
2763            if let Some(diff_state) = snapshot.diffs.get(&excerpt.buffer_id) {
2764                let diff = &diff_state.diff;
2765                let base_text = &diff_state.base_text;
2766                let buffer = &excerpt.buffer;
2767                let excerpt_start = *excerpts.start();
2768                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2769                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2770                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2771                let edit_buffer_start =
2772                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2773                let edit_buffer_end =
2774                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2775                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2776                let edit_anchor_range =
2777                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2778
2779                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2780                    let hunk_anchor = (excerpt.id, hunk.buffer_range.start);
2781                    if !hunk_anchor.1.is_valid(buffer) {
2782                        continue;
2783                    }
2784
2785                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2786                    let hunk_excerpt_start = excerpt_start
2787                        + ExcerptOffset::new(
2788                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2789                        );
2790                    let hunk_excerpt_end = excerpt_end.min(
2791                        excerpt_start
2792                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2793                    );
2794
2795                    self.push_buffer_content_transform(
2796                        snapshot,
2797                        new_diff_transforms,
2798                        hunk_excerpt_start,
2799                        *end_of_current_insert,
2800                    );
2801
2802                    // For every existing hunk, determine if it was previously expanded
2803                    // and if it should currently be expanded.
2804                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_anchor);
2805                    let should_expand_hunk = match &change_kind {
2806                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2807                            self.all_diff_hunks_expanded
2808                        }
2809                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2810                            let intersects = hunk_buffer_range.is_empty()
2811                                || hunk_buffer_range.end > edit_buffer_start;
2812                            if *expand {
2813                                intersects
2814                                    || was_previously_expanded
2815                                    || self.all_diff_hunks_expanded
2816                            } else {
2817                                !intersects
2818                                    && (was_previously_expanded || self.all_diff_hunks_expanded)
2819                            }
2820                        }
2821                        _ => was_previously_expanded || self.all_diff_hunks_expanded,
2822                    };
2823
2824                    if should_expand_hunk {
2825                        did_expand_hunks = true;
2826                        log::trace!(
2827                            "expanding hunk {:?}",
2828                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2829                        );
2830
2831                        if !hunk.diff_base_byte_range.is_empty()
2832                            && hunk_buffer_range.start >= edit_buffer_start
2833                            && hunk_buffer_range.start <= excerpt_buffer_end
2834                        {
2835                            let mut text_cursor =
2836                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2837                            let mut base_text_summary =
2838                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2839
2840                            let mut has_trailing_newline = false;
2841                            if base_text_summary.last_line_chars > 0 {
2842                                base_text_summary += TextSummary::newline();
2843                                has_trailing_newline = true;
2844                            }
2845
2846                            new_diff_transforms.push(
2847                                DiffTransform::DeletedHunk {
2848                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2849                                    summary: base_text_summary,
2850                                    buffer_id: excerpt.buffer_id,
2851                                    hunk_anchor,
2852                                    has_trailing_newline,
2853                                },
2854                                &(),
2855                            );
2856                        }
2857
2858                        if !hunk_buffer_range.is_empty() {
2859                            *end_of_current_insert = Some((
2860                                hunk_excerpt_end.min(excerpt_end),
2861                                hunk_anchor.0,
2862                                hunk_anchor.1,
2863                            ));
2864                        }
2865                    }
2866                }
2867            }
2868
2869            if excerpts.end(&()) <= edit.new.end {
2870                excerpts.next(&());
2871            } else {
2872                break;
2873            }
2874        }
2875
2876        did_expand_hunks || !old_expanded_hunks.is_empty()
2877    }
2878
2879    fn append_diff_transforms(
2880        &self,
2881        new_transforms: &mut SumTree<DiffTransform>,
2882        subtree: SumTree<DiffTransform>,
2883    ) {
2884        if let Some(DiffTransform::BufferContent {
2885            inserted_hunk_anchor,
2886            summary,
2887        }) = subtree.first()
2888        {
2889            if self.extend_last_buffer_content_transform(
2890                new_transforms,
2891                *inserted_hunk_anchor,
2892                *summary,
2893            ) {
2894                let mut cursor = subtree.cursor::<()>(&());
2895                cursor.next(&());
2896                cursor.next(&());
2897                new_transforms.append(cursor.suffix(&()), &());
2898                return;
2899            }
2900        }
2901        new_transforms.append(subtree, &());
2902    }
2903
2904    fn push_diff_transform(
2905        &self,
2906        new_transforms: &mut SumTree<DiffTransform>,
2907        transform: DiffTransform,
2908    ) {
2909        if let DiffTransform::BufferContent {
2910            inserted_hunk_anchor,
2911            summary,
2912        } = transform
2913        {
2914            if self.extend_last_buffer_content_transform(
2915                new_transforms,
2916                inserted_hunk_anchor,
2917                summary,
2918            ) {
2919                return;
2920            }
2921        }
2922        new_transforms.push(transform, &());
2923    }
2924
2925    fn push_buffer_content_transform(
2926        &self,
2927        old_snapshot: &MultiBufferSnapshot,
2928        new_transforms: &mut SumTree<DiffTransform>,
2929        end_offset: ExcerptOffset,
2930        current_inserted_hunk: Option<(ExcerptOffset, ExcerptId, text::Anchor)>,
2931    ) {
2932        let inserted_region =
2933            current_inserted_hunk.map(|(insertion_end_offset, excerpt_id, anchor)| {
2934                (
2935                    end_offset.min(insertion_end_offset),
2936                    Some((excerpt_id, anchor)),
2937                )
2938            });
2939        let unchanged_region = [(end_offset, None)];
2940
2941        for (end_offset, inserted_hunk_anchor) in
2942            inserted_region.into_iter().chain(unchanged_region)
2943        {
2944            let start_offset = new_transforms.summary().excerpt_len();
2945            if end_offset <= start_offset {
2946                continue;
2947            }
2948            let summary_to_add = old_snapshot
2949                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2950
2951            if !self.extend_last_buffer_content_transform(
2952                new_transforms,
2953                inserted_hunk_anchor,
2954                summary_to_add,
2955            ) {
2956                new_transforms.push(
2957                    DiffTransform::BufferContent {
2958                        summary: summary_to_add,
2959                        inserted_hunk_anchor,
2960                    },
2961                    &(),
2962                )
2963            }
2964        }
2965    }
2966
2967    fn extend_last_buffer_content_transform(
2968        &self,
2969        new_transforms: &mut SumTree<DiffTransform>,
2970        new_inserted_hunk_anchor: Option<(ExcerptId, text::Anchor)>,
2971        summary_to_add: TextSummary,
2972    ) -> bool {
2973        let mut did_extend = false;
2974        new_transforms.update_last(
2975            |last_transform| {
2976                if let DiffTransform::BufferContent {
2977                    summary,
2978                    inserted_hunk_anchor,
2979                } = last_transform
2980                {
2981                    if *inserted_hunk_anchor == new_inserted_hunk_anchor {
2982                        *summary += summary_to_add;
2983                        did_extend = true;
2984                    }
2985                }
2986            },
2987            &(),
2988        );
2989        did_extend
2990    }
2991}
2992
2993#[cfg(any(test, feature = "test-support"))]
2994impl MultiBuffer {
2995    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2996        let buffer = cx.new(|cx| Buffer::local(text, cx));
2997        cx.new(|cx| Self::singleton(buffer, cx))
2998    }
2999
3000    pub fn build_multi<const COUNT: usize>(
3001        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3002        cx: &mut gpui::App,
3003    ) -> Entity<Self> {
3004        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3005        for (text, ranges) in excerpts {
3006            let buffer = cx.new(|cx| Buffer::local(text, cx));
3007            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3008                context: range,
3009                primary: None,
3010            });
3011            multi.update(cx, |multi, cx| {
3012                multi.push_excerpts(buffer, excerpt_ranges, cx)
3013            });
3014        }
3015
3016        multi
3017    }
3018
3019    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3020        cx.new(|cx| Self::singleton(buffer, cx))
3021    }
3022
3023    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3024        cx.new(|cx| {
3025            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3026            let mutation_count = rng.gen_range(1..=5);
3027            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3028            multibuffer
3029        })
3030    }
3031
3032    pub fn randomly_edit(
3033        &mut self,
3034        rng: &mut impl rand::Rng,
3035        edit_count: usize,
3036        cx: &mut Context<Self>,
3037    ) {
3038        use util::RandomCharIter;
3039
3040        let snapshot = self.read(cx);
3041        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3042        let mut last_end = None;
3043        for _ in 0..edit_count {
3044            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3045                break;
3046            }
3047
3048            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3049            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3050            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3051            last_end = Some(end);
3052
3053            let mut range = start..end;
3054            if rng.gen_bool(0.2) {
3055                mem::swap(&mut range.start, &mut range.end);
3056            }
3057
3058            let new_text_len = rng.gen_range(0..10);
3059            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3060
3061            edits.push((range, new_text.into()));
3062        }
3063        log::info!("mutating multi-buffer with {:?}", edits);
3064        drop(snapshot);
3065
3066        self.edit(edits, None, cx);
3067    }
3068
3069    pub fn randomly_edit_excerpts(
3070        &mut self,
3071        rng: &mut impl rand::Rng,
3072        mutation_count: usize,
3073        cx: &mut Context<Self>,
3074    ) {
3075        use rand::prelude::*;
3076        use std::env;
3077        use util::RandomCharIter;
3078
3079        let max_excerpts = env::var("MAX_EXCERPTS")
3080            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3081            .unwrap_or(5);
3082
3083        let mut buffers = Vec::new();
3084        for _ in 0..mutation_count {
3085            if rng.gen_bool(0.05) {
3086                log::info!("Clearing multi-buffer");
3087                self.clear(cx);
3088                continue;
3089            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3090                let ids = self.excerpt_ids();
3091                let mut excerpts = HashSet::default();
3092                for _ in 0..rng.gen_range(0..ids.len()) {
3093                    excerpts.extend(ids.choose(rng).copied());
3094                }
3095
3096                let line_count = rng.gen_range(0..5);
3097
3098                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3099
3100                self.expand_excerpts(
3101                    excerpts.iter().cloned(),
3102                    line_count,
3103                    ExpandExcerptDirection::UpAndDown,
3104                    cx,
3105                );
3106                continue;
3107            }
3108
3109            let excerpt_ids = self.excerpt_ids();
3110            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3111                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3112                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3113                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3114                    let buffer = buffers.last().unwrap().read(cx);
3115                    log::info!(
3116                        "Creating new buffer {} with text: {:?}",
3117                        buffer.remote_id(),
3118                        buffer.text()
3119                    );
3120                    buffers.last().unwrap().clone()
3121                } else {
3122                    self.buffers
3123                        .borrow()
3124                        .values()
3125                        .choose(rng)
3126                        .unwrap()
3127                        .buffer
3128                        .clone()
3129                };
3130
3131                let buffer = buffer_handle.read(cx);
3132                let buffer_text = buffer.text();
3133                let ranges = (0..rng.gen_range(0..5))
3134                    .map(|_| {
3135                        let end_ix =
3136                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3137                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3138                        ExcerptRange {
3139                            context: start_ix..end_ix,
3140                            primary: None,
3141                        }
3142                    })
3143                    .collect::<Vec<_>>();
3144                log::info!(
3145                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3146                    buffer_handle.read(cx).remote_id(),
3147                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3148                    ranges
3149                        .iter()
3150                        .map(|r| &buffer_text[r.context.clone()])
3151                        .collect::<Vec<_>>()
3152                );
3153
3154                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3155                log::info!("Inserted with ids: {:?}", excerpt_id);
3156            } else {
3157                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3158                let mut excerpts_to_remove = excerpt_ids
3159                    .choose_multiple(rng, remove_count)
3160                    .cloned()
3161                    .collect::<Vec<_>>();
3162                let snapshot = self.snapshot.borrow();
3163                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3164                drop(snapshot);
3165                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3166                self.remove_excerpts(excerpts_to_remove, cx);
3167            }
3168        }
3169    }
3170
3171    pub fn randomly_mutate(
3172        &mut self,
3173        rng: &mut impl rand::Rng,
3174        mutation_count: usize,
3175        cx: &mut Context<Self>,
3176    ) {
3177        use rand::prelude::*;
3178
3179        if rng.gen_bool(0.7) || self.singleton {
3180            let buffer = self
3181                .buffers
3182                .borrow()
3183                .values()
3184                .choose(rng)
3185                .map(|state| state.buffer.clone());
3186
3187            if let Some(buffer) = buffer {
3188                buffer.update(cx, |buffer, cx| {
3189                    if rng.gen() {
3190                        buffer.randomly_edit(rng, mutation_count, cx);
3191                    } else {
3192                        buffer.randomly_undo_redo(rng, cx);
3193                    }
3194                });
3195            } else {
3196                self.randomly_edit(rng, mutation_count, cx);
3197            }
3198        } else {
3199            self.randomly_edit_excerpts(rng, mutation_count, cx);
3200        }
3201
3202        self.check_invariants(cx);
3203    }
3204
3205    fn check_invariants(&self, cx: &App) {
3206        self.read(cx).check_invariants();
3207    }
3208}
3209
3210impl EventEmitter<Event> for MultiBuffer {}
3211
3212impl MultiBufferSnapshot {
3213    pub fn text(&self) -> String {
3214        self.chunks(0..self.len(), false)
3215            .map(|chunk| chunk.text)
3216            .collect()
3217    }
3218
3219    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3220        self.reversed_chunks_in_range(0..position.to_offset(self))
3221            .flat_map(|c| c.chars().rev())
3222    }
3223
3224    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3225        let mut cursor = self.cursor::<usize>();
3226        cursor.seek(&range.end);
3227        let current_chunks = cursor.region().as_ref().map(|region| {
3228            let start_overshoot = range.start.saturating_sub(region.range.start);
3229            let end_overshoot = range.end - region.range.start;
3230            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3231            let start = region.buffer_range.start + start_overshoot;
3232            region.buffer.reversed_chunks_in_range(start..end)
3233        });
3234        ReversedMultiBufferChunks {
3235            cursor,
3236            current_chunks,
3237            start: range.start,
3238            offset: range.end,
3239        }
3240    }
3241
3242    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3243        let offset = position.to_offset(self);
3244        self.text_for_range(offset..self.len())
3245            .flat_map(|chunk| chunk.chars())
3246    }
3247
3248    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3249        self.chunks(range, false).map(|chunk| chunk.text)
3250    }
3251
3252    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3253        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3254            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3255    }
3256
3257    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3258    where
3259        T: ToOffset,
3260    {
3261        let position = position.to_offset(self);
3262        position == self.clip_offset(position, Bias::Left)
3263            && self
3264                .bytes_in_range(position..self.len())
3265                .flatten()
3266                .copied()
3267                .take(needle.len())
3268                .eq(needle.bytes())
3269    }
3270
3271    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3272        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3273    }
3274
3275    pub fn diff_hunks_in_range<T: ToOffset>(
3276        &self,
3277        range: Range<T>,
3278    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3279        let range = range.start.to_offset(self)..range.end.to_offset(self);
3280        self.lift_buffer_metadata(range.clone(), move |buffer, buffer_range| {
3281            let diff = self.diffs.get(&buffer.remote_id())?;
3282            let buffer_start = buffer.anchor_before(buffer_range.start);
3283            let buffer_end = buffer.anchor_after(buffer_range.end);
3284            Some(
3285                diff.diff
3286                    .hunks_intersecting_range(buffer_start..buffer_end, buffer)
3287                    .map(|hunk| {
3288                        (
3289                            Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
3290                            hunk,
3291                        )
3292                    }),
3293            )
3294        })
3295        .map(|(range, hunk, excerpt)| {
3296            let end_row = if range.end.column == 0 {
3297                range.end.row
3298            } else {
3299                range.end.row + 1
3300            };
3301            MultiBufferDiffHunk {
3302                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3303                buffer_id: excerpt.buffer_id,
3304                excerpt_id: excerpt.id,
3305                buffer_range: hunk.buffer_range.clone(),
3306                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3307            }
3308        })
3309    }
3310
3311    pub fn excerpt_ids_for_range<T: ToOffset>(
3312        &self,
3313        range: Range<T>,
3314    ) -> impl Iterator<Item = ExcerptId> + '_ {
3315        let range = range.start.to_offset(self)..range.end.to_offset(self);
3316        let mut cursor = self.cursor::<usize>();
3317        cursor.seek(&range.start);
3318        std::iter::from_fn(move || {
3319            let region = cursor.region()?;
3320            if region.range.start >= range.end {
3321                return None;
3322            }
3323            cursor.next_excerpt();
3324            Some(region.excerpt.id)
3325        })
3326    }
3327
3328    pub fn buffer_ids_for_range<T: ToOffset>(
3329        &self,
3330        range: Range<T>,
3331    ) -> impl Iterator<Item = BufferId> + '_ {
3332        let range = range.start.to_offset(self)..range.end.to_offset(self);
3333        let mut cursor = self.cursor::<usize>();
3334        cursor.seek(&range.start);
3335        std::iter::from_fn(move || {
3336            let region = cursor.region()?;
3337            if region.range.start >= range.end {
3338                return None;
3339            }
3340            cursor.next_excerpt();
3341            Some(region.excerpt.buffer_id)
3342        })
3343    }
3344
3345    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3346        &self,
3347        ranges: impl Iterator<Item = Range<T>>,
3348    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3349        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3350    }
3351
3352    pub fn range_to_buffer_ranges<T: ToOffset>(
3353        &self,
3354        range: Range<T>,
3355    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3356        let start = range.start.to_offset(&self);
3357        let end = range.end.to_offset(&self);
3358
3359        let mut cursor = self.cursor::<usize>();
3360        cursor.seek(&start);
3361
3362        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3363        while let Some(region) = cursor.region() {
3364            if region.range.start > end {
3365                break;
3366            }
3367            if region.is_main_buffer {
3368                let start_overshoot = start.saturating_sub(region.range.start);
3369                let end_overshoot = end.saturating_sub(region.range.start);
3370                let start = region
3371                    .buffer_range
3372                    .end
3373                    .min(region.buffer_range.start + start_overshoot);
3374                let end = region
3375                    .buffer_range
3376                    .end
3377                    .min(region.buffer_range.start + end_overshoot);
3378                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3379                    *excerpt_id == region.excerpt.id && prev_range.end == start
3380                }) {
3381                    prev.1.end = end;
3382                } else {
3383                    result.push((region.buffer, start..end, region.excerpt.id));
3384                }
3385            }
3386            cursor.next();
3387        }
3388        result
3389    }
3390
3391    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3392    /// coordinates.
3393    ///
3394    /// The given callback will be called for every excerpt intersecting the given range. It will
3395    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3396    /// The callback should return an iterator of metadata items from that buffer, each paired
3397    /// with a buffer range.
3398    ///
3399    /// The returned iterator yields each of these metadata items, paired with its range in
3400    /// multi-buffer coordinates.
3401    fn lift_buffer_metadata<'a, D, M, I>(
3402        &'a self,
3403        range: Range<usize>,
3404        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<usize>) -> Option<I>,
3405    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3406    where
3407        I: Iterator<Item = (Range<D>, M)> + 'a,
3408        D: TextDimension + Ord + Sub<D, Output = D>,
3409    {
3410        let max_position = D::from_text_summary(&self.text_summary());
3411        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3412        let mut cursor = self.cursor::<DimensionPair<usize, D>>();
3413
3414        // Find the excerpt and buffer offset where the given range ends.
3415        cursor.seek(&DimensionPair {
3416            key: range.end,
3417            value: None,
3418        });
3419        let mut range_end = None;
3420        while let Some(region) = cursor.region() {
3421            if region.is_main_buffer {
3422                let mut buffer_end = region.buffer_range.start.key;
3423                let overshoot = range.end.saturating_sub(region.range.start.key);
3424                buffer_end.add_assign(&overshoot);
3425                range_end = Some((region.excerpt.id, buffer_end));
3426                break;
3427            }
3428            cursor.next();
3429        }
3430
3431        cursor.seek(&DimensionPair {
3432            key: range.start,
3433            value: None,
3434        });
3435
3436        if cursor.region().is_some_and(|region| !region.is_main_buffer) {
3437            cursor.prev();
3438        }
3439
3440        iter::from_fn(move || loop {
3441            let excerpt = cursor.excerpt()?;
3442
3443            // If we have already retrieved metadata for this excerpt, continue to use it.
3444            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3445                .as_mut()
3446                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3447            {
3448                Some(metadata)
3449            }
3450            // Otherwise, compute the intersection of the input range with the excerpt's range,
3451            // and retrieve the metadata for the resulting range.
3452            else {
3453                let region = cursor.region()?;
3454                let buffer_start = if region.is_main_buffer {
3455                    let start_overshoot = range.start.saturating_sub(region.range.start.key);
3456                    region.buffer_range.start.key + start_overshoot
3457                } else {
3458                    cursor.main_buffer_position()?.key
3459                };
3460                let mut buffer_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3461                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3462                    if excerpt.id == end_excerpt_id {
3463                        buffer_end = buffer_end.min(end_buffer_offset);
3464                    }
3465                }
3466
3467                if let Some(iterator) =
3468                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3469                {
3470                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3471                } else {
3472                    None
3473                }
3474            };
3475
3476            // Visit each metadata item.
3477            if let Some((range, metadata)) = metadata_iter.and_then(Iterator::next) {
3478                // Find the multibuffer regions that contain the start and end of
3479                // the metadata item's range.
3480                if range.start > D::default() {
3481                    while let Some(region) = cursor.region() {
3482                        if !region.is_main_buffer
3483                            || region.buffer.remote_id() == excerpt.buffer_id
3484                                && region.buffer_range.end.value.unwrap() < range.start
3485                        {
3486                            cursor.next();
3487                        } else {
3488                            break;
3489                        }
3490                    }
3491                }
3492                let start_region = cursor.region()?;
3493                while let Some(region) = cursor.region() {
3494                    if !region.is_main_buffer
3495                        || region.buffer.remote_id() == excerpt.buffer_id
3496                            && region.buffer_range.end.value.unwrap() <= range.end
3497                    {
3498                        cursor.next();
3499                    } else {
3500                        break;
3501                    }
3502                }
3503                let end_region = cursor
3504                    .region()
3505                    .filter(|region| region.buffer.remote_id() == excerpt.buffer_id);
3506
3507                // Convert the metadata item's range into multibuffer coordinates.
3508                let mut start = start_region.range.start.value.unwrap();
3509                let region_buffer_start = start_region.buffer_range.start.value.unwrap();
3510                if start_region.is_main_buffer && range.start > region_buffer_start {
3511                    start.add_assign(&(range.start - region_buffer_start));
3512                }
3513                let mut end = max_position;
3514                if let Some(end_region) = end_region {
3515                    end = end_region.range.start.value.unwrap();
3516                    debug_assert!(end_region.is_main_buffer);
3517                    let region_buffer_start = end_region.buffer_range.start.value.unwrap();
3518                    if range.end > region_buffer_start {
3519                        end.add_assign(&(range.end - region_buffer_start));
3520                    }
3521                }
3522
3523                return Some((start..end, metadata, excerpt));
3524            }
3525            // When there are no more metadata items for this excerpt, move to the next excerpt.
3526            else {
3527                current_excerpt_metadata.take();
3528                cursor.next_excerpt();
3529            }
3530        })
3531    }
3532
3533    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3534        let offset = position.to_offset(self);
3535
3536        // Go to the region containing the given offset.
3537        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3538        cursor.seek(&DimensionPair {
3539            key: offset,
3540            value: None,
3541        });
3542        let mut region = cursor.region()?;
3543        if region.range.start.key == offset || !region.is_main_buffer {
3544            cursor.prev();
3545            region = cursor.region()?;
3546        }
3547
3548        // Find the corresponding buffer offset.
3549        let overshoot = if region.is_main_buffer {
3550            offset - region.range.start.key
3551        } else {
3552            0
3553        };
3554        let mut max_buffer_offset = region
3555            .buffer
3556            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3557
3558        loop {
3559            let excerpt = cursor.excerpt()?;
3560            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3561            let buffer_offset = excerpt_end.min(max_buffer_offset);
3562            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3563            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3564
3565            if let Some(diff_state) = self.diffs.get(&excerpt.buffer_id) {
3566                for hunk in diff_state.diff.hunks_intersecting_range_rev(
3567                    excerpt.range.context.start..buffer_end,
3568                    &excerpt.buffer,
3569                ) {
3570                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3571                    if hunk.row_range.end >= buffer_end_row {
3572                        continue;
3573                    }
3574
3575                    let hunk_start = Point::new(hunk.row_range.start, 0);
3576                    let hunk_end = Point::new(hunk.row_range.end, 0);
3577
3578                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3579                        key: hunk_range.start,
3580                        value: None,
3581                    });
3582
3583                    let mut region = cursor.region()?;
3584                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3585                    {
3586                        cursor.prev();
3587                        region = cursor.region()?;
3588                    }
3589
3590                    let overshoot = if region.is_main_buffer {
3591                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3592                    } else {
3593                        Point::zero()
3594                    };
3595                    let start = region.range.start.value.unwrap() + overshoot;
3596
3597                    while let Some(region) = cursor.region() {
3598                        if !region.is_main_buffer
3599                            || region.buffer_range.end.value.unwrap() <= hunk_end
3600                        {
3601                            cursor.next();
3602                        } else {
3603                            break;
3604                        }
3605                    }
3606
3607                    let end = if let Some(region) = cursor.region() {
3608                        let overshoot = if region.is_main_buffer {
3609                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3610                        } else {
3611                            Point::zero()
3612                        };
3613                        region.range.start.value.unwrap() + overshoot
3614                    } else {
3615                        self.max_point()
3616                    };
3617
3618                    return Some(MultiBufferDiffHunk {
3619                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3620                        buffer_id: excerpt.buffer_id,
3621                        excerpt_id: excerpt.id,
3622                        buffer_range: hunk.buffer_range.clone(),
3623                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3624                    });
3625                }
3626            }
3627
3628            cursor.prev_excerpt();
3629            max_buffer_offset = usize::MAX;
3630        }
3631    }
3632
3633    pub fn has_diff_hunks(&self) -> bool {
3634        self.diffs.values().any(|diff| !diff.diff.is_empty())
3635    }
3636
3637    pub fn surrounding_word<T: ToOffset>(
3638        &self,
3639        start: T,
3640        for_completion: bool,
3641    ) -> (Range<usize>, Option<CharKind>) {
3642        let mut start = start.to_offset(self);
3643        let mut end = start;
3644        let mut next_chars = self.chars_at(start).peekable();
3645        let mut prev_chars = self.reversed_chars_at(start).peekable();
3646
3647        let classifier = self
3648            .char_classifier_at(start)
3649            .for_completion(for_completion);
3650
3651        let word_kind = cmp::max(
3652            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3653            next_chars.peek().copied().map(|c| classifier.kind(c)),
3654        );
3655
3656        for ch in prev_chars {
3657            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3658                start -= ch.len_utf8();
3659            } else {
3660                break;
3661            }
3662        }
3663
3664        for ch in next_chars {
3665            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3666                end += ch.len_utf8();
3667            } else {
3668                break;
3669            }
3670        }
3671
3672        (start..end, word_kind)
3673    }
3674
3675    pub fn is_singleton(&self) -> bool {
3676        self.singleton
3677    }
3678
3679    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3680        if self.singleton {
3681            self.excerpts
3682                .iter()
3683                .next()
3684                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3685        } else {
3686            None
3687        }
3688    }
3689
3690    pub fn len(&self) -> usize {
3691        self.diff_transforms.summary().output.len
3692    }
3693
3694    pub fn is_empty(&self) -> bool {
3695        self.excerpts.summary().text.len == 0
3696    }
3697
3698    pub fn widest_line_number(&self) -> u32 {
3699        self.excerpts.summary().widest_line_number + 1
3700    }
3701
3702    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3703        let range = range.start.to_offset(self)..range.end.to_offset(self);
3704        let mut excerpts = self.cursor::<usize>();
3705        excerpts.seek(&range.start);
3706
3707        let mut chunk;
3708        let mut has_trailing_newline;
3709        let excerpt_bytes;
3710        if let Some(region) = excerpts.region() {
3711            let mut bytes = region.buffer.bytes_in_range(
3712                region.buffer_range.start + range.start - region.range.start
3713                    ..(region.buffer_range.start + range.end - region.range.start)
3714                        .min(region.buffer_range.end),
3715            );
3716            chunk = bytes.next().unwrap_or(&[][..]);
3717            excerpt_bytes = Some(bytes);
3718            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3719            if chunk.is_empty() && has_trailing_newline {
3720                chunk = b"\n";
3721                has_trailing_newline = false;
3722            }
3723        } else {
3724            chunk = &[][..];
3725            excerpt_bytes = None;
3726            has_trailing_newline = false;
3727        };
3728
3729        MultiBufferBytes {
3730            range,
3731            cursor: excerpts,
3732            excerpt_bytes,
3733            has_trailing_newline,
3734            chunk,
3735        }
3736    }
3737
3738    pub fn reversed_bytes_in_range<T: ToOffset>(
3739        &self,
3740        range: Range<T>,
3741    ) -> ReversedMultiBufferBytes {
3742        let range = range.start.to_offset(self)..range.end.to_offset(self);
3743        let mut chunks = self.reversed_chunks_in_range(range.clone());
3744        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3745        ReversedMultiBufferBytes {
3746            range,
3747            chunks,
3748            chunk,
3749        }
3750    }
3751
3752    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3753        let mut cursor = self.cursor::<Point>();
3754        cursor.seek(&Point::new(start_row.0, 0));
3755        let mut result = MultiBufferRows {
3756            point: Point::new(0, 0),
3757            is_empty: self.excerpts.is_empty(),
3758            cursor,
3759        };
3760        result.seek(start_row);
3761        result
3762    }
3763
3764    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3765        let mut chunks = MultiBufferChunks {
3766            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3767            range: 0..0,
3768            excerpts: self.excerpts.cursor(&()),
3769            diff_transforms: self.diff_transforms.cursor(&()),
3770            diffs: &self.diffs,
3771            diff_base_chunks: None,
3772            excerpt_chunks: None,
3773            buffer_chunk: None,
3774            language_aware,
3775        };
3776        let range = range.start.to_offset(self)..range.end.to_offset(self);
3777        chunks.seek(range);
3778        chunks
3779    }
3780
3781    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3782        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3783    }
3784
3785    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3786        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3787    }
3788
3789    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3790        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3791    }
3792
3793    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3794        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3795            buffer.clip_point_utf16(Unclipped(point), bias)
3796        })
3797    }
3798
3799    pub fn offset_to_point(&self, offset: usize) -> Point {
3800        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3801    }
3802
3803    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3804        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3805    }
3806
3807    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3808        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3809    }
3810
3811    pub fn point_to_offset(&self, point: Point) -> usize {
3812        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3813    }
3814
3815    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3816        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3817    }
3818
3819    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3820        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3821    }
3822
3823    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3824        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3825    }
3826
3827    fn clip_dimension<D>(
3828        &self,
3829        position: D,
3830        bias: Bias,
3831        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3832    ) -> D
3833    where
3834        D: TextDimension + Ord + Sub<D, Output = D>,
3835    {
3836        let mut cursor = self.cursor();
3837        cursor.seek(&position);
3838        if let Some(region) = cursor.region() {
3839            if position >= region.range.end {
3840                return region.range.end;
3841            }
3842            let overshoot = position - region.range.start;
3843            let mut buffer_position = region.buffer_range.start;
3844            buffer_position.add_assign(&overshoot);
3845            let clipped_buffer_position =
3846                clip_buffer_position(&region.buffer, buffer_position, bias);
3847            let mut position = region.range.start;
3848            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3849            position
3850        } else {
3851            D::from_text_summary(&self.text_summary())
3852        }
3853    }
3854
3855    fn convert_dimension<D1, D2>(
3856        &self,
3857        key: D1,
3858        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3859    ) -> D2
3860    where
3861        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3862        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3863    {
3864        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3865        cursor.seek(&DimensionPair { key, value: None });
3866        if let Some(region) = cursor.region() {
3867            if key >= region.range.end.key {
3868                return region.range.end.value.unwrap();
3869            }
3870            let start_key = region.range.start.key;
3871            let start_value = region.range.start.value.unwrap();
3872            let buffer_start_key = region.buffer_range.start.key;
3873            let buffer_start_value = region.buffer_range.start.value.unwrap();
3874            let mut buffer_key = buffer_start_key;
3875            buffer_key.add_assign(&(key - start_key));
3876            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
3877            let mut result = start_value;
3878            result.add_assign(&(buffer_value - buffer_start_value));
3879            result
3880        } else {
3881            D2::from_text_summary(&self.text_summary())
3882        }
3883    }
3884
3885    pub fn point_to_buffer_offset<T: ToOffset>(
3886        &self,
3887        point: T,
3888    ) -> Option<(&BufferSnapshot, usize)> {
3889        let offset = point.to_offset(self);
3890        let mut cursor = self.cursor::<usize>();
3891        cursor.seek(&offset);
3892        let region = cursor.region()?;
3893        let overshoot = offset - region.range.start;
3894        let buffer_offset = region.buffer_range.start + overshoot;
3895        Some((region.buffer, buffer_offset))
3896    }
3897
3898    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
3899        let mut cursor = self.cursor::<Point>();
3900        cursor.seek(&point);
3901        let region = cursor.region()?;
3902        let overshoot = point - region.range.start;
3903        let buffer_offset = region.buffer_range.start + overshoot;
3904        Some((region.buffer, buffer_offset, region.is_main_buffer))
3905    }
3906
3907    pub fn suggested_indents(
3908        &self,
3909        rows: impl IntoIterator<Item = u32>,
3910        cx: &App,
3911    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3912        let mut result = BTreeMap::new();
3913
3914        let mut rows_for_excerpt = Vec::new();
3915        let mut cursor = self.cursor::<Point>();
3916        let mut rows = rows.into_iter().peekable();
3917        let mut prev_row = u32::MAX;
3918        let mut prev_language_indent_size = IndentSize::default();
3919
3920        while let Some(row) = rows.next() {
3921            cursor.seek(&Point::new(row, 0));
3922            let Some(region) = cursor.region() else {
3923                continue;
3924            };
3925
3926            // Retrieve the language and indent size once for each disjoint region being indented.
3927            let single_indent_size = if row.saturating_sub(1) == prev_row {
3928                prev_language_indent_size
3929            } else {
3930                region
3931                    .buffer
3932                    .language_indent_size_at(Point::new(row, 0), cx)
3933            };
3934            prev_language_indent_size = single_indent_size;
3935            prev_row = row;
3936
3937            let start_buffer_row = region.buffer_range.start.row;
3938            let start_multibuffer_row = region.range.start.row;
3939            let end_multibuffer_row = region.range.end.row;
3940
3941            rows_for_excerpt.push(row);
3942            while let Some(next_row) = rows.peek().copied() {
3943                if end_multibuffer_row > next_row {
3944                    rows_for_excerpt.push(next_row);
3945                    rows.next();
3946                } else {
3947                    break;
3948                }
3949            }
3950
3951            let buffer_rows = rows_for_excerpt
3952                .drain(..)
3953                .map(|row| start_buffer_row + row - start_multibuffer_row);
3954            let buffer_indents = region
3955                .buffer
3956                .suggested_indents(buffer_rows, single_indent_size);
3957            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
3958                (
3959                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
3960                    indent,
3961                )
3962            });
3963            result.extend(multibuffer_indents);
3964        }
3965
3966        result
3967    }
3968
3969    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
3970        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3971            let mut size = buffer.indent_size_for_line(range.start.row);
3972            size.len = size
3973                .len
3974                .min(range.end.column)
3975                .saturating_sub(range.start.column);
3976            size
3977        } else {
3978            IndentSize::spaces(0)
3979        }
3980    }
3981
3982    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
3983        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3984            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
3985        } else {
3986            LineIndent::spaces(0)
3987        }
3988    }
3989
3990    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
3991        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
3992
3993        if self.settings_at(0, cx).extend_comment_on_newline {
3994            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
3995                let delimiters = language_scope.line_comment_prefixes();
3996                for delimiter in delimiters {
3997                    if *self
3998                        .chars_at(Point::new(row.0, indent.len() as u32))
3999                        .take(delimiter.chars().count())
4000                        .collect::<String>()
4001                        .as_str()
4002                        == **delimiter
4003                    {
4004                        indent.push_str(&delimiter);
4005                        break;
4006                    }
4007                }
4008            }
4009        }
4010
4011        indent
4012    }
4013
4014    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4015        while row.0 > 0 {
4016            row.0 -= 1;
4017            if !self.is_line_blank(row) {
4018                return Some(row);
4019            }
4020        }
4021        None
4022    }
4023
4024    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4025        if let Some((_, range)) = self.buffer_line_for_row(row) {
4026            range.end.column - range.start.column
4027        } else {
4028            0
4029        }
4030    }
4031
4032    pub fn buffer_line_for_row(
4033        &self,
4034        row: MultiBufferRow,
4035    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4036        let mut cursor = self.cursor::<Point>();
4037        let point = Point::new(row.0, 0);
4038        cursor.seek(&point);
4039        let region = cursor.region()?;
4040        let overshoot = point.min(region.range.end) - region.range.start;
4041        let buffer_point = region.buffer_range.start + overshoot;
4042        if buffer_point.row > region.buffer_range.end.row {
4043            return None;
4044        }
4045        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4046        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4047            .min(region.buffer_range.end);
4048        Some((region.buffer, line_start..line_end))
4049    }
4050
4051    pub fn max_point(&self) -> Point {
4052        self.text_summary().lines
4053    }
4054
4055    pub fn max_row(&self) -> MultiBufferRow {
4056        MultiBufferRow(self.text_summary().lines.row)
4057    }
4058
4059    pub fn text_summary(&self) -> TextSummary {
4060        self.diff_transforms.summary().output
4061    }
4062
4063    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4064    where
4065        D: TextDimension,
4066        O: ToOffset,
4067    {
4068        let range = range.start.to_offset(self)..range.end.to_offset(self);
4069        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4070        cursor.seek(&range.start, Bias::Right, &());
4071
4072        let Some(first_transform) = cursor.item() else {
4073            return D::from_text_summary(&TextSummary::default());
4074        };
4075
4076        let diff_transform_start = cursor.start().0;
4077        let diff_transform_end = cursor.end(&()).0;
4078        let diff_start = range.start;
4079        let start_overshoot = diff_start - diff_transform_start;
4080        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4081
4082        let mut result = match first_transform {
4083            DiffTransform::BufferContent { .. } => {
4084                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4085                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4086                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4087            }
4088            DiffTransform::DeletedHunk {
4089                buffer_id,
4090                base_text_byte_range,
4091                has_trailing_newline,
4092                ..
4093            } => {
4094                let buffer_start = base_text_byte_range.start + start_overshoot;
4095                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4096                let Some(buffer_diff) = self.diffs.get(buffer_id) else {
4097                    panic!("{:?} is in non-existent deleted hunk", range.start)
4098                };
4099
4100                let include_trailing_newline =
4101                    *has_trailing_newline && range.end >= diff_transform_end;
4102                if include_trailing_newline {
4103                    buffer_end -= 1;
4104                }
4105
4106                let mut summary = buffer_diff
4107                    .base_text
4108                    .text_summary_for_range::<D, _>(buffer_start..buffer_end);
4109
4110                if include_trailing_newline {
4111                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4112                }
4113
4114                summary
4115            }
4116        };
4117        if range.end < diff_transform_end {
4118            return result;
4119        }
4120
4121        cursor.next(&());
4122        result.add_assign(&D::from_text_summary(&cursor.summary(
4123            &range.end,
4124            Bias::Right,
4125            &(),
4126        )));
4127
4128        let Some(last_transform) = cursor.item() else {
4129            return result;
4130        };
4131
4132        let overshoot = range.end - cursor.start().0;
4133        let suffix = match last_transform {
4134            DiffTransform::BufferContent { .. } => {
4135                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4136                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4137            }
4138            DiffTransform::DeletedHunk {
4139                base_text_byte_range,
4140                buffer_id,
4141                has_trailing_newline,
4142                ..
4143            } => {
4144                let buffer_end = base_text_byte_range.start + overshoot;
4145                let Some(buffer_diff) = self.diffs.get(buffer_id) else {
4146                    panic!("{:?} is in non-extant deleted hunk", range.end)
4147                };
4148
4149                let mut suffix = buffer_diff
4150                    .base_text
4151                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4152                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4153                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4154                }
4155                suffix
4156            }
4157        };
4158
4159        result.add_assign(&suffix);
4160        result
4161    }
4162
4163    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4164    where
4165        D: TextDimension,
4166    {
4167        // let mut range = range.start..range.end;
4168        let mut summary = D::zero(&());
4169        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4170        cursor.seek(&range.start, Bias::Right, &());
4171        if let Some(excerpt) = cursor.item() {
4172            let mut end_before_newline = cursor.end(&());
4173            if excerpt.has_trailing_newline {
4174                end_before_newline -= ExcerptOffset::new(1);
4175            }
4176
4177            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4178            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4179            let end_in_excerpt =
4180                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4181            summary.add_assign(
4182                &excerpt
4183                    .buffer
4184                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4185            );
4186
4187            if range.end > end_before_newline {
4188                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4189            }
4190
4191            cursor.next(&());
4192        }
4193
4194        if range.end > *cursor.start() {
4195            summary.add_assign(
4196                &cursor
4197                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4198                    .0,
4199            );
4200            if let Some(excerpt) = cursor.item() {
4201                range.end = cmp::max(*cursor.start(), range.end);
4202
4203                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4204                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4205                summary.add_assign(
4206                    &excerpt
4207                        .buffer
4208                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4209                );
4210            }
4211        }
4212
4213        summary
4214    }
4215
4216    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4217    where
4218        D: TextDimension + Ord + Sub<D, Output = D>,
4219    {
4220        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4221        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4222
4223        cursor.seek(locator, Bias::Left, &());
4224        if cursor.item().is_none() {
4225            cursor.next(&());
4226        }
4227
4228        let mut excerpt_position = D::from_text_summary(&cursor.start().text);
4229        if let Some(excerpt) = cursor.item() {
4230            if excerpt.id == anchor.excerpt_id {
4231                let excerpt_buffer_start =
4232                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4233                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4234                let buffer_position = cmp::min(
4235                    excerpt_buffer_end,
4236                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
4237                );
4238                if buffer_position > excerpt_buffer_start {
4239                    excerpt_position.add_assign(&(buffer_position - excerpt_buffer_start));
4240                }
4241            }
4242        }
4243
4244        let mut diff_transforms_cursor = self
4245            .diff_transforms
4246            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4247        diff_transforms_cursor.seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
4248
4249        self.resolve_summary_for_anchor(anchor, excerpt_position, &mut diff_transforms_cursor)
4250    }
4251
4252    fn resolve_summary_for_anchor<D>(
4253        &self,
4254        anchor: &Anchor,
4255        excerpt_position: D,
4256        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4257    ) -> D
4258    where
4259        D: TextDimension + Ord + Sub<D, Output = D>,
4260    {
4261        loop {
4262            let transform_end_position = diff_transforms.end(&()).0 .0;
4263            let at_transform_end =
4264                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4265            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4266                diff_transforms.next(&());
4267                continue;
4268            }
4269
4270            let mut position = diff_transforms.start().1 .0;
4271            match diff_transforms.item() {
4272                Some(DiffTransform::DeletedHunk {
4273                    buffer_id,
4274                    base_text_byte_range,
4275                    ..
4276                }) => {
4277                    let mut in_deleted_hunk = false;
4278                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4279                        if let Some(diff) = self.diffs.get(buffer_id) {
4280                            if diff.base_text.can_resolve(&diff_base_anchor) {
4281                                let base_text_offset = diff_base_anchor.to_offset(&diff.base_text);
4282                                if base_text_offset >= base_text_byte_range.start
4283                                    && base_text_offset <= base_text_byte_range.end
4284                                {
4285                                    let position_in_hunk =
4286                                        diff.base_text.text_summary_for_range::<D, _>(
4287                                            base_text_byte_range.start..base_text_offset,
4288                                        );
4289                                    position.add_assign(&position_in_hunk);
4290                                    in_deleted_hunk = true;
4291                                } else if at_transform_end {
4292                                    diff_transforms.next(&());
4293                                    continue;
4294                                }
4295                            }
4296                        }
4297                    }
4298                    if !in_deleted_hunk {
4299                        position = diff_transforms.end(&()).1 .0;
4300                    }
4301                }
4302                _ => {
4303                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4304                        diff_transforms.next(&());
4305                        continue;
4306                    }
4307                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4308                    position.add_assign(&overshoot);
4309                }
4310            }
4311
4312            return position;
4313        }
4314    }
4315
4316    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4317        let mut cursor = self
4318            .excerpts
4319            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4320        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4321
4322        cursor.seek(&Some(locator), Bias::Left, &());
4323        if cursor.item().is_none() {
4324            cursor.next(&());
4325        }
4326
4327        let mut position = cursor.start().1;
4328        if let Some(excerpt) = cursor.item() {
4329            if excerpt.id == anchor.excerpt_id {
4330                let excerpt_buffer_start = excerpt
4331                    .buffer
4332                    .offset_for_anchor(&excerpt.range.context.start);
4333                let excerpt_buffer_end =
4334                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4335                let buffer_position = cmp::min(
4336                    excerpt_buffer_end,
4337                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4338                );
4339                if buffer_position > excerpt_buffer_start {
4340                    position.value += buffer_position - excerpt_buffer_start;
4341                }
4342            }
4343        }
4344        position
4345    }
4346
4347    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4348    where
4349        D: TextDimension + Ord + Sub<D, Output = D>,
4350        I: 'a + IntoIterator<Item = &'a Anchor>,
4351    {
4352        let mut anchors = anchors.into_iter().peekable();
4353        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4354        let mut diff_transforms_cursor = self
4355            .diff_transforms
4356            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4357        diff_transforms_cursor.next(&());
4358
4359        let mut summaries = Vec::new();
4360        while let Some(anchor) = anchors.peek() {
4361            let excerpt_id = anchor.excerpt_id;
4362            let excerpt_anchors = iter::from_fn(|| {
4363                let anchor = anchors.peek()?;
4364                if anchor.excerpt_id == excerpt_id {
4365                    Some(anchors.next().unwrap())
4366                } else {
4367                    None
4368                }
4369            });
4370
4371            let locator = self.excerpt_locator_for_id(excerpt_id);
4372            cursor.seek_forward(locator, Bias::Left, &());
4373            if cursor.item().is_none() {
4374                cursor.next(&());
4375            }
4376
4377            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4378            if let Some(excerpt) = cursor.item().filter(|excerpt| excerpt.id == excerpt_id) {
4379                let excerpt_buffer_start =
4380                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4381                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4382                for (buffer_summary, anchor) in excerpt
4383                    .buffer
4384                    .summaries_for_anchors_with_payload::<D, _, _>(
4385                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4386                    )
4387                {
4388                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4389                    let mut position = excerpt_start_position;
4390                    if summary > excerpt_buffer_start {
4391                        position.add_assign(&(summary - excerpt_buffer_start));
4392                    }
4393
4394                    if position > diff_transforms_cursor.start().0 .0 {
4395                        diff_transforms_cursor.seek_forward(
4396                            &ExcerptDimension(position),
4397                            Bias::Left,
4398                            &(),
4399                        );
4400                    }
4401
4402                    summaries.push(self.resolve_summary_for_anchor(
4403                        anchor,
4404                        position,
4405                        &mut diff_transforms_cursor,
4406                    ));
4407                }
4408            } else {
4409                diff_transforms_cursor.seek_forward(
4410                    &ExcerptDimension(excerpt_start_position),
4411                    Bias::Left,
4412                    &(),
4413                );
4414                let position = self.resolve_summary_for_anchor(
4415                    &Anchor::max(),
4416                    excerpt_start_position,
4417                    &mut diff_transforms_cursor,
4418                );
4419                summaries.extend(excerpt_anchors.map(|_| position));
4420            }
4421        }
4422
4423        summaries
4424    }
4425
4426    pub fn dimensions_from_points<'a, D>(
4427        &'a self,
4428        points: impl 'a + IntoIterator<Item = Point>,
4429    ) -> impl 'a + Iterator<Item = D>
4430    where
4431        D: TextDimension + Sub<D, Output = D>,
4432    {
4433        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4434        cursor.seek(&DimensionPair {
4435            key: Point::default(),
4436            value: None,
4437        });
4438        let mut points = points.into_iter();
4439        iter::from_fn(move || {
4440            let point = points.next()?;
4441
4442            cursor.seek_forward(&DimensionPair {
4443                key: point,
4444                value: None,
4445            });
4446
4447            if let Some(region) = cursor.region() {
4448                let overshoot = point - region.range.start.key;
4449                let buffer_point = region.buffer_range.start.key + overshoot;
4450                let mut position = region.range.start.value.unwrap();
4451                position.add_assign(
4452                    &region
4453                        .buffer
4454                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4455                );
4456                return Some(position);
4457            } else {
4458                return Some(D::from_text_summary(&self.text_summary()));
4459            }
4460        })
4461    }
4462
4463    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4464    where
4465        I: 'a + IntoIterator<Item = &'a Anchor>,
4466    {
4467        let mut anchors = anchors.into_iter().enumerate().peekable();
4468        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4469        cursor.next(&());
4470
4471        let mut result = Vec::new();
4472
4473        while let Some((_, anchor)) = anchors.peek() {
4474            let old_excerpt_id = anchor.excerpt_id;
4475
4476            // Find the location where this anchor's excerpt should be.
4477            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4478            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4479
4480            if cursor.item().is_none() {
4481                cursor.next(&());
4482            }
4483
4484            let next_excerpt = cursor.item();
4485            let prev_excerpt = cursor.prev_item();
4486
4487            // Process all of the anchors for this excerpt.
4488            while let Some((_, anchor)) = anchors.peek() {
4489                if anchor.excerpt_id != old_excerpt_id {
4490                    break;
4491                }
4492                let (anchor_ix, anchor) = anchors.next().unwrap();
4493                let mut anchor = *anchor;
4494
4495                // Leave min and max anchors unchanged if invalid or
4496                // if the old excerpt still exists at this location
4497                let mut kept_position = next_excerpt
4498                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4499                    || old_excerpt_id == ExcerptId::max()
4500                    || old_excerpt_id == ExcerptId::min();
4501
4502                // If the old excerpt no longer exists at this location, then attempt to
4503                // find an equivalent position for this anchor in an adjacent excerpt.
4504                if !kept_position {
4505                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4506                        if excerpt.contains(&anchor) {
4507                            anchor.excerpt_id = excerpt.id;
4508                            kept_position = true;
4509                            break;
4510                        }
4511                    }
4512                }
4513
4514                // If there's no adjacent excerpt that contains the anchor's position,
4515                // then report that the anchor has lost its position.
4516                if !kept_position {
4517                    anchor = if let Some(excerpt) = next_excerpt {
4518                        let mut text_anchor = excerpt
4519                            .range
4520                            .context
4521                            .start
4522                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4523                        if text_anchor
4524                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4525                            .is_gt()
4526                        {
4527                            text_anchor = excerpt.range.context.end;
4528                        }
4529                        Anchor {
4530                            buffer_id: Some(excerpt.buffer_id),
4531                            excerpt_id: excerpt.id,
4532                            text_anchor,
4533                            diff_base_anchor: None,
4534                        }
4535                    } else if let Some(excerpt) = prev_excerpt {
4536                        let mut text_anchor = excerpt
4537                            .range
4538                            .context
4539                            .end
4540                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4541                        if text_anchor
4542                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4543                            .is_lt()
4544                        {
4545                            text_anchor = excerpt.range.context.start;
4546                        }
4547                        Anchor {
4548                            buffer_id: Some(excerpt.buffer_id),
4549                            excerpt_id: excerpt.id,
4550                            text_anchor,
4551                            diff_base_anchor: None,
4552                        }
4553                    } else if anchor.text_anchor.bias == Bias::Left {
4554                        Anchor::min()
4555                    } else {
4556                        Anchor::max()
4557                    };
4558                }
4559
4560                result.push((anchor_ix, anchor, kept_position));
4561            }
4562        }
4563        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4564        result
4565    }
4566
4567    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4568        self.anchor_at(position, Bias::Left)
4569    }
4570
4571    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4572        self.anchor_at(position, Bias::Right)
4573    }
4574
4575    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4576        let offset = position.to_offset(self);
4577
4578        // Find the given position in the diff transforms. Determine the corresponding
4579        // offset in the excerpts, and whether the position is within a deleted hunk.
4580        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4581        diff_transforms.seek(&offset, Bias::Right, &());
4582
4583        if offset == diff_transforms.start().0 && bias == Bias::Left {
4584            if let Some(prev_item) = diff_transforms.prev_item() {
4585                match prev_item {
4586                    DiffTransform::DeletedHunk { .. } => {
4587                        diff_transforms.prev(&());
4588                    }
4589                    _ => {}
4590                }
4591            }
4592        }
4593        let offset_in_transform = offset - diff_transforms.start().0;
4594        let mut excerpt_offset = diff_transforms.start().1;
4595        let mut diff_base_anchor = None;
4596        if let Some(DiffTransform::DeletedHunk {
4597            buffer_id,
4598            base_text_byte_range,
4599            has_trailing_newline,
4600            ..
4601        }) = diff_transforms.item()
4602        {
4603            let diff_base = self.diffs.get(buffer_id).expect("missing diff base");
4604            if offset_in_transform > base_text_byte_range.len() {
4605                debug_assert!(*has_trailing_newline);
4606                bias = Bias::Right;
4607            } else {
4608                diff_base_anchor = Some(
4609                    diff_base
4610                        .base_text
4611                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4612                );
4613                bias = Bias::Left;
4614            }
4615        } else {
4616            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4617        };
4618
4619        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4620            return Anchor {
4621                buffer_id: Some(buffer_id),
4622                excerpt_id: *excerpt_id,
4623                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4624                diff_base_anchor,
4625            };
4626        }
4627
4628        let mut excerpts = self
4629            .excerpts
4630            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4631        excerpts.seek(&excerpt_offset, Bias::Right, &());
4632        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4633            excerpts.prev(&());
4634        }
4635        if let Some(excerpt) = excerpts.item() {
4636            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4637            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4638                overshoot -= 1;
4639                bias = Bias::Right;
4640            }
4641
4642            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4643            let text_anchor =
4644                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4645            Anchor {
4646                buffer_id: Some(excerpt.buffer_id),
4647                excerpt_id: excerpt.id,
4648                text_anchor,
4649                diff_base_anchor,
4650            }
4651        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4652            Anchor::min()
4653        } else {
4654            Anchor::max()
4655        }
4656    }
4657
4658    /// Returns an anchor for the given excerpt and text anchor,
4659    /// returns None if the excerpt_id is no longer valid.
4660    pub fn anchor_in_excerpt(
4661        &self,
4662        excerpt_id: ExcerptId,
4663        text_anchor: text::Anchor,
4664    ) -> Option<Anchor> {
4665        let locator = self.excerpt_locator_for_id(excerpt_id);
4666        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4667        cursor.seek(locator, Bias::Left, &());
4668        if let Some(excerpt) = cursor.item() {
4669            if excerpt.id == excerpt_id {
4670                let text_anchor = excerpt.clip_anchor(text_anchor);
4671                drop(cursor);
4672                return Some(Anchor {
4673                    buffer_id: Some(excerpt.buffer_id),
4674                    excerpt_id,
4675                    text_anchor,
4676                    diff_base_anchor: None,
4677                });
4678            }
4679        }
4680        None
4681    }
4682
4683    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4684        Some(self.excerpt(excerpt_id)?.range.context.clone())
4685    }
4686
4687    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4688        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4689            true
4690        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4691            excerpt.buffer.can_resolve(&anchor.text_anchor)
4692        } else {
4693            false
4694        }
4695    }
4696
4697    pub fn excerpts(
4698        &self,
4699    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4700        self.excerpts
4701            .iter()
4702            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4703    }
4704
4705    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4706        let excerpts = self.excerpts.cursor(&());
4707        let diff_transforms = self.diff_transforms.cursor(&());
4708        MultiBufferCursor {
4709            excerpts,
4710            diff_transforms,
4711            diffs: &self.diffs,
4712            cached_region: None,
4713        }
4714    }
4715
4716    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4717        let start_locator = self.excerpt_locator_for_id(id);
4718        let mut excerpts = self
4719            .excerpts
4720            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4721        excerpts.seek(&Some(start_locator), Bias::Left, &());
4722        excerpts.prev(&());
4723
4724        let mut diff_transforms = self
4725            .diff_transforms
4726            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4727        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4728        if diff_transforms.end(&()).1 < excerpts.start().1 {
4729            diff_transforms.next(&());
4730        }
4731
4732        let excerpt = excerpts.item()?;
4733        Some(MultiBufferExcerpt {
4734            excerpt,
4735            offset: diff_transforms.start().0 .0,
4736            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4737            excerpt_offset: excerpts.start().1.clone(),
4738            diff_transforms,
4739        })
4740    }
4741
4742    pub fn excerpt_boundaries_in_range<R, T>(
4743        &self,
4744        range: R,
4745    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4746    where
4747        R: RangeBounds<T>,
4748        T: ToOffset,
4749    {
4750        let start_offset;
4751        let start = match range.start_bound() {
4752            Bound::Included(start) => {
4753                start_offset = start.to_offset(self);
4754                Bound::Included(start_offset)
4755            }
4756            Bound::Excluded(_) => {
4757                panic!("not supported")
4758            }
4759            Bound::Unbounded => {
4760                start_offset = 0;
4761                Bound::Unbounded
4762            }
4763        };
4764        let end = match range.end_bound() {
4765            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4766            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4767            Bound::Unbounded => Bound::Unbounded,
4768        };
4769        let bounds = (start, end);
4770
4771        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4772        cursor.seek(&DimensionPair {
4773            key: start_offset,
4774            value: None,
4775        });
4776
4777        if cursor
4778            .region()
4779            .is_some_and(|region| bounds.contains(&region.range.start.key))
4780        {
4781            cursor.prev_excerpt();
4782        } else {
4783            cursor.seek_to_start_of_current_excerpt();
4784        }
4785        let mut prev_region = cursor.region();
4786
4787        cursor.next_excerpt();
4788
4789        let mut visited_end = false;
4790        iter::from_fn(move || {
4791            if self.singleton {
4792                return None;
4793            }
4794
4795            let next_region = cursor.region();
4796            cursor.next_excerpt();
4797
4798            let next_region_start = if let Some(region) = &next_region {
4799                if !bounds.contains(&region.range.start.key) {
4800                    return None;
4801                }
4802                region.range.start.value.unwrap()
4803            } else {
4804                if !bounds.contains(&self.len()) {
4805                    return None;
4806                }
4807                self.max_point()
4808            };
4809            let next_region_end = if let Some(region) = cursor.region() {
4810                region.range.start.value.unwrap()
4811            } else {
4812                self.max_point()
4813            };
4814
4815            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4816                id: region.excerpt.id,
4817                buffer: region.excerpt.buffer.clone(),
4818                buffer_id: region.excerpt.buffer_id,
4819                range: region.excerpt.range.clone(),
4820                end_row: MultiBufferRow(next_region_start.row),
4821            });
4822
4823            let next = next_region.as_ref().map(|region| ExcerptInfo {
4824                id: region.excerpt.id,
4825                buffer: region.excerpt.buffer.clone(),
4826                buffer_id: region.excerpt.buffer_id,
4827                range: region.excerpt.range.clone(),
4828                end_row: if region.excerpt.has_trailing_newline {
4829                    MultiBufferRow(next_region_end.row - 1)
4830                } else {
4831                    MultiBufferRow(next_region_end.row)
4832                },
4833            });
4834
4835            if next.is_none() {
4836                if visited_end {
4837                    return None;
4838                } else {
4839                    visited_end = true;
4840                }
4841            }
4842
4843            let row = MultiBufferRow(next_region_start.row);
4844
4845            prev_region = next_region;
4846
4847            Some(ExcerptBoundary { row, prev, next })
4848        })
4849    }
4850
4851    pub fn edit_count(&self) -> usize {
4852        self.edit_count
4853    }
4854
4855    pub fn non_text_state_update_count(&self) -> usize {
4856        self.non_text_state_update_count
4857    }
4858
4859    /// Returns the smallest enclosing bracket ranges containing the given range or
4860    /// None if no brackets contain range or the range is not contained in a single
4861    /// excerpt
4862    ///
4863    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4864    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4865        &self,
4866        range: Range<T>,
4867        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4868    ) -> Option<(Range<usize>, Range<usize>)> {
4869        let range = range.start.to_offset(self)..range.end.to_offset(self);
4870        let mut excerpt = self.excerpt_containing(range.clone())?;
4871        let buffer = excerpt.buffer();
4872        let excerpt_buffer_range = excerpt.buffer_range();
4873
4874        // Filter to ranges contained in the excerpt
4875        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4876            excerpt_buffer_range.contains(&open.start)
4877                && excerpt_buffer_range.contains(&close.end)
4878                && range_filter.map_or(true, |filter| filter(buffer, open, close))
4879        };
4880
4881        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4882            excerpt.map_range_to_buffer(range),
4883            Some(&range_filter),
4884        )?;
4885
4886        Some((
4887            excerpt.map_range_from_buffer(open),
4888            excerpt.map_range_from_buffer(close),
4889        ))
4890    }
4891
4892    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4893    /// not contained in a single excerpt
4894    pub fn enclosing_bracket_ranges<T: ToOffset>(
4895        &self,
4896        range: Range<T>,
4897    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4898        let range = range.start.to_offset(self)..range.end.to_offset(self);
4899        let mut excerpt = self.excerpt_containing(range.clone())?;
4900
4901        Some(
4902            excerpt
4903                .buffer()
4904                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4905                .filter_map(move |(open, close)| {
4906                    if excerpt.contains_buffer_range(open.start..close.end) {
4907                        Some((
4908                            excerpt.map_range_from_buffer(open),
4909                            excerpt.map_range_from_buffer(close),
4910                        ))
4911                    } else {
4912                        None
4913                    }
4914                }),
4915        )
4916    }
4917
4918    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4919    /// not contained in a single excerpt
4920    pub fn text_object_ranges<T: ToOffset>(
4921        &self,
4922        range: Range<T>,
4923        options: TreeSitterOptions,
4924    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4925        let range = range.start.to_offset(self)..range.end.to_offset(self);
4926        self.excerpt_containing(range.clone())
4927            .map(|mut excerpt| {
4928                excerpt
4929                    .buffer()
4930                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4931                    .filter_map(move |(range, text_object)| {
4932                        if excerpt.contains_buffer_range(range.clone()) {
4933                            Some((excerpt.map_range_from_buffer(range), text_object))
4934                        } else {
4935                            None
4936                        }
4937                    })
4938            })
4939            .into_iter()
4940            .flatten()
4941    }
4942
4943    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4944    /// not contained in a single excerpt
4945    pub fn bracket_ranges<T: ToOffset>(
4946        &self,
4947        range: Range<T>,
4948    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4949        let range = range.start.to_offset(self)..range.end.to_offset(self);
4950        let mut excerpt = self.excerpt_containing(range.clone())?;
4951
4952        Some(
4953            excerpt
4954                .buffer()
4955                .bracket_ranges(excerpt.map_range_to_buffer(range))
4956                .filter_map(move |(start_bracket_range, close_bracket_range)| {
4957                    let buffer_range = start_bracket_range.start..close_bracket_range.end;
4958                    if excerpt.contains_buffer_range(buffer_range) {
4959                        Some((
4960                            excerpt.map_range_from_buffer(start_bracket_range),
4961                            excerpt.map_range_from_buffer(close_bracket_range),
4962                        ))
4963                    } else {
4964                        None
4965                    }
4966                }),
4967        )
4968    }
4969
4970    pub fn redacted_ranges<'a, T: ToOffset>(
4971        &'a self,
4972        range: Range<T>,
4973        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
4974    ) -> impl Iterator<Item = Range<usize>> + 'a {
4975        let range = range.start.to_offset(self)..range.end.to_offset(self);
4976        self.lift_buffer_metadata(range, move |buffer, range| {
4977            if redaction_enabled(buffer.file()) {
4978                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
4979            } else {
4980                None
4981            }
4982        })
4983        .map(|(range, _, _)| range)
4984    }
4985
4986    pub fn runnable_ranges(
4987        &self,
4988        range: Range<Anchor>,
4989    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
4990        let range = range.start.to_offset(self)..range.end.to_offset(self);
4991        self.lift_buffer_metadata(range, move |buffer, range| {
4992            Some(
4993                buffer
4994                    .runnable_ranges(range.clone())
4995                    .filter(move |runnable| {
4996                        runnable.run_range.start >= range.start
4997                            && runnable.run_range.end < range.end
4998                    })
4999                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5000            )
5001        })
5002        .map(|(run_range, runnable, _)| language::RunnableRange {
5003            run_range,
5004            ..runnable
5005        })
5006    }
5007
5008    pub fn line_indents(
5009        &self,
5010        start_row: MultiBufferRow,
5011        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5012    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5013        let max_point = self.max_point();
5014        let mut cursor = self.cursor::<Point>();
5015        cursor.seek(&Point::new(start_row.0, 0));
5016        iter::from_fn(move || {
5017            let mut region = cursor.region()?;
5018            while !buffer_filter(&region.excerpt.buffer) {
5019                cursor.next();
5020                region = cursor.region()?;
5021            }
5022            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5023            let buffer_start_row =
5024                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5025
5026            let buffer_end_row = if region.is_main_buffer
5027                && (region.has_trailing_newline || region.range.end == max_point)
5028            {
5029                region.buffer_range.end.row
5030            } else {
5031                region.buffer_range.end.row.saturating_sub(1)
5032            };
5033
5034            let line_indents = region
5035                .buffer
5036                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5037            cursor.next();
5038            return Some(line_indents.map(move |(buffer_row, indent)| {
5039                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5040                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5041            }));
5042        })
5043        .flatten()
5044    }
5045
5046    pub fn reversed_line_indents(
5047        &self,
5048        end_row: MultiBufferRow,
5049        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5050    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5051        let max_point = self.max_point();
5052        let mut cursor = self.cursor::<Point>();
5053        cursor.seek(&Point::new(end_row.0, 0));
5054        iter::from_fn(move || {
5055            let mut region = cursor.region()?;
5056            while !buffer_filter(&region.excerpt.buffer) {
5057                cursor.prev();
5058                region = cursor.region()?;
5059            }
5060
5061            let buffer_start_row = region.buffer_range.start.row;
5062            let buffer_end_row = if region.is_main_buffer
5063                && (region.has_trailing_newline || region.range.end == max_point)
5064            {
5065                region.buffer_range.end.row + 1
5066            } else {
5067                region.buffer_range.end.row
5068            };
5069
5070            let overshoot = end_row.0 - region.range.start.row;
5071            let buffer_end_row =
5072                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5073
5074            let line_indents = region
5075                .buffer
5076                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5077            cursor.prev();
5078            return Some(line_indents.map(move |(buffer_row, indent)| {
5079                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5080                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5081            }));
5082        })
5083        .flatten()
5084    }
5085
5086    pub async fn enclosing_indent(
5087        &self,
5088        mut target_row: MultiBufferRow,
5089    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5090        let max_row = MultiBufferRow(self.max_point().row);
5091        if target_row >= max_row {
5092            return None;
5093        }
5094
5095        let mut target_indent = self.line_indent_for_row(target_row);
5096
5097        // If the current row is at the start of an indented block, we want to return this
5098        // block as the enclosing indent.
5099        if !target_indent.is_line_empty() && target_row < max_row {
5100            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5101            if !next_line_indent.is_line_empty()
5102                && target_indent.raw_len() < next_line_indent.raw_len()
5103            {
5104                target_indent = next_line_indent;
5105                target_row.0 += 1;
5106            }
5107        }
5108
5109        const SEARCH_ROW_LIMIT: u32 = 25000;
5110        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5111        const YIELD_INTERVAL: u32 = 100;
5112
5113        let mut accessed_row_counter = 0;
5114
5115        // If there is a blank line at the current row, search for the next non indented lines
5116        if target_indent.is_line_empty() {
5117            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5118            let end =
5119                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5120
5121            let mut non_empty_line_above = None;
5122            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5123                if row < start {
5124                    break;
5125                }
5126                accessed_row_counter += 1;
5127                if accessed_row_counter == YIELD_INTERVAL {
5128                    accessed_row_counter = 0;
5129                    yield_now().await;
5130                }
5131                if !indent.is_line_empty() {
5132                    non_empty_line_above = Some((row, indent));
5133                    break;
5134                }
5135            }
5136
5137            let mut non_empty_line_below = None;
5138            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5139                if row > end {
5140                    break;
5141                }
5142                accessed_row_counter += 1;
5143                if accessed_row_counter == YIELD_INTERVAL {
5144                    accessed_row_counter = 0;
5145                    yield_now().await;
5146                }
5147                if !indent.is_line_empty() {
5148                    non_empty_line_below = Some((row, indent));
5149                    break;
5150                }
5151            }
5152
5153            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5154                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5155                    if above_indent.raw_len() >= below_indent.raw_len() {
5156                        (above_row, above_indent)
5157                    } else {
5158                        (below_row, below_indent)
5159                    }
5160                }
5161                (Some(above), None) => above,
5162                (None, Some(below)) => below,
5163                _ => return None,
5164            };
5165
5166            target_indent = indent;
5167            target_row = row;
5168        }
5169
5170        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5171        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5172
5173        let mut start_indent = None;
5174        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5175            if row < start {
5176                break;
5177            }
5178            accessed_row_counter += 1;
5179            if accessed_row_counter == YIELD_INTERVAL {
5180                accessed_row_counter = 0;
5181                yield_now().await;
5182            }
5183            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5184                start_indent = Some((row, indent));
5185                break;
5186            }
5187        }
5188        let (start_row, start_indent_size) = start_indent?;
5189
5190        let mut end_indent = (end, None);
5191        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5192            if row > end {
5193                break;
5194            }
5195            accessed_row_counter += 1;
5196            if accessed_row_counter == YIELD_INTERVAL {
5197                accessed_row_counter = 0;
5198                yield_now().await;
5199            }
5200            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5201                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5202                break;
5203            }
5204        }
5205        let (end_row, end_indent_size) = end_indent;
5206
5207        let indent = if let Some(end_indent_size) = end_indent_size {
5208            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5209                start_indent_size
5210            } else {
5211                end_indent_size
5212            }
5213        } else {
5214            start_indent_size
5215        };
5216
5217        Some((start_row..end_row, indent))
5218    }
5219
5220    pub fn indent_guides_in_range<T: ToPoint>(
5221        &self,
5222        range: Range<T>,
5223        ignore_disabled_for_language: bool,
5224        cx: &App,
5225    ) -> impl Iterator<Item = IndentGuide> {
5226        let range = range.start.to_point(self)..range.end.to_point(self);
5227        let start_row = MultiBufferRow(range.start.row);
5228        let end_row = MultiBufferRow(range.end.row);
5229
5230        let mut row_indents = self.line_indents(start_row, |buffer| {
5231            let settings =
5232                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5233            settings.indent_guides.enabled || ignore_disabled_for_language
5234        });
5235
5236        let mut result = Vec::new();
5237        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5238
5239        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5240            if first_row > end_row {
5241                break;
5242            }
5243            let current_depth = indent_stack.len() as u32;
5244
5245            let settings =
5246                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5247            let tab_size = settings.tab_size.get() as u32;
5248
5249            // When encountering empty, continue until found useful line indent
5250            // then add to the indent stack with the depth found
5251            let mut found_indent = false;
5252            let mut last_row = first_row;
5253            if line_indent.is_line_empty() {
5254                while !found_indent {
5255                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5256                        break;
5257                    };
5258                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5259                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5260                        break;
5261                    }
5262
5263                    if new_line_indent.is_line_empty() {
5264                        continue;
5265                    }
5266                    last_row = target_row.min(end_row);
5267                    line_indent = new_line_indent;
5268                    found_indent = true;
5269                    break;
5270                }
5271            } else {
5272                found_indent = true
5273            }
5274
5275            let depth = if found_indent {
5276                line_indent.len(tab_size) / tab_size
5277                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5278            } else {
5279                current_depth
5280            };
5281
5282            match depth.cmp(&current_depth) {
5283                cmp::Ordering::Less => {
5284                    for _ in 0..(current_depth - depth) {
5285                        let mut indent = indent_stack.pop().unwrap();
5286                        if last_row != first_row {
5287                            // In this case, we landed on an empty row, had to seek forward,
5288                            // and discovered that the indent we where on is ending.
5289                            // This means that the last display row must
5290                            // be on line that ends this indent range, so we
5291                            // should display the range up to the first non-empty line
5292                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5293                        }
5294
5295                        result.push(indent)
5296                    }
5297                }
5298                cmp::Ordering::Greater => {
5299                    for next_depth in current_depth..depth {
5300                        indent_stack.push(IndentGuide {
5301                            buffer_id: buffer.remote_id(),
5302                            start_row: first_row,
5303                            end_row: last_row,
5304                            depth: next_depth,
5305                            tab_size,
5306                            settings: settings.indent_guides,
5307                        });
5308                    }
5309                }
5310                _ => {}
5311            }
5312
5313            for indent in indent_stack.iter_mut() {
5314                indent.end_row = last_row;
5315            }
5316        }
5317
5318        result.extend(indent_stack);
5319        result.into_iter()
5320    }
5321
5322    pub fn trailing_excerpt_update_count(&self) -> usize {
5323        self.trailing_excerpt_update_count
5324    }
5325
5326    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5327        self.point_to_buffer_offset(point)
5328            .and_then(|(buffer, _)| buffer.file())
5329    }
5330
5331    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5332        self.point_to_buffer_offset(point)
5333            .and_then(|(buffer, offset)| buffer.language_at(offset))
5334    }
5335
5336    pub fn settings_at<'a, T: ToOffset>(
5337        &'a self,
5338        point: T,
5339        cx: &'a App,
5340    ) -> Cow<'a, LanguageSettings> {
5341        let mut language = None;
5342        let mut file = None;
5343        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5344            language = buffer.language_at(offset);
5345            file = buffer.file();
5346        }
5347        language_settings(language.map(|l| l.name()), file, cx)
5348    }
5349
5350    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5351        self.point_to_buffer_offset(point)
5352            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5353    }
5354
5355    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5356        self.point_to_buffer_offset(point)
5357            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5358            .unwrap_or_default()
5359    }
5360
5361    pub fn language_indent_size_at<T: ToOffset>(
5362        &self,
5363        position: T,
5364        cx: &App,
5365    ) -> Option<IndentSize> {
5366        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5367        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5368    }
5369
5370    pub fn is_dirty(&self) -> bool {
5371        self.is_dirty
5372    }
5373
5374    pub fn has_deleted_file(&self) -> bool {
5375        self.has_deleted_file
5376    }
5377
5378    pub fn has_conflict(&self) -> bool {
5379        self.has_conflict
5380    }
5381
5382    pub fn has_diagnostics(&self) -> bool {
5383        self.excerpts
5384            .iter()
5385            .any(|excerpt| excerpt.buffer.has_diagnostics())
5386    }
5387
5388    pub fn diagnostic_group(
5389        &self,
5390        buffer_id: BufferId,
5391        group_id: usize,
5392    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5393        self.lift_buffer_metadata(0..self.len(), move |buffer, _| {
5394            if buffer.remote_id() != buffer_id {
5395                return None;
5396            };
5397            Some(
5398                buffer
5399                    .diagnostic_group(group_id)
5400                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5401            )
5402        })
5403        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5404    }
5405
5406    pub fn diagnostics_in_range<'a, T, O>(
5407        &'a self,
5408        range: Range<T>,
5409    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
5410    where
5411        T: 'a + ToOffset,
5412        O: 'a + text::FromAnchor + Copy + TextDimension + Ord + Sub<O, Output = O> + fmt::Debug,
5413    {
5414        let range = range.start.to_offset(self)..range.end.to_offset(self);
5415        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5416            Some(
5417                buffer
5418                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5419                    .map(|entry| (entry.range, entry.diagnostic)),
5420            )
5421        })
5422        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5423    }
5424
5425    pub fn syntax_ancestor<T: ToOffset>(
5426        &self,
5427        range: Range<T>,
5428    ) -> Option<(tree_sitter::Node, Range<usize>)> {
5429        let range = range.start.to_offset(self)..range.end.to_offset(self);
5430        let mut excerpt = self.excerpt_containing(range.clone())?;
5431        let node = excerpt
5432            .buffer()
5433            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5434        Some((node, excerpt.map_range_from_buffer(node.byte_range())))
5435    }
5436
5437    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5438        let (excerpt_id, _, buffer) = self.as_singleton()?;
5439        let outline = buffer.outline(theme)?;
5440        Some(Outline::new(
5441            outline
5442                .items
5443                .into_iter()
5444                .flat_map(|item| {
5445                    Some(OutlineItem {
5446                        depth: item.depth,
5447                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5448                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5449                        text: item.text,
5450                        highlight_ranges: item.highlight_ranges,
5451                        name_ranges: item.name_ranges,
5452                        body_range: item.body_range.and_then(|body_range| {
5453                            Some(
5454                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5455                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5456                            )
5457                        }),
5458                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5459                            Some(
5460                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5461                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5462                            )
5463                        }),
5464                    })
5465                })
5466                .collect(),
5467        ))
5468    }
5469
5470    pub fn symbols_containing<T: ToOffset>(
5471        &self,
5472        offset: T,
5473        theme: Option<&SyntaxTheme>,
5474    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5475        let anchor = self.anchor_before(offset);
5476        let excerpt_id = anchor.excerpt_id;
5477        let excerpt = self.excerpt(excerpt_id)?;
5478        Some((
5479            excerpt.buffer_id,
5480            excerpt
5481                .buffer
5482                .symbols_containing(anchor.text_anchor, theme)
5483                .into_iter()
5484                .flatten()
5485                .flat_map(|item| {
5486                    Some(OutlineItem {
5487                        depth: item.depth,
5488                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5489                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5490                        text: item.text,
5491                        highlight_ranges: item.highlight_ranges,
5492                        name_ranges: item.name_ranges,
5493                        body_range: item.body_range.and_then(|body_range| {
5494                            Some(
5495                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5496                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5497                            )
5498                        }),
5499                        annotation_range: item.annotation_range.and_then(|body_range| {
5500                            Some(
5501                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5502                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5503                            )
5504                        }),
5505                    })
5506                })
5507                .collect(),
5508        ))
5509    }
5510
5511    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5512        if id == ExcerptId::min() {
5513            Locator::min_ref()
5514        } else if id == ExcerptId::max() {
5515            Locator::max_ref()
5516        } else {
5517            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5518            cursor.seek(&id, Bias::Left, &());
5519            if let Some(entry) = cursor.item() {
5520                if entry.id == id {
5521                    return &entry.locator;
5522                }
5523            }
5524            panic!("invalid excerpt id {:?}", id)
5525        }
5526    }
5527
5528    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5529    fn excerpt_locators_for_ids(
5530        &self,
5531        ids: impl IntoIterator<Item = ExcerptId>,
5532    ) -> SmallVec<[Locator; 1]> {
5533        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5534        sorted_ids.sort_unstable();
5535        let mut locators = SmallVec::new();
5536
5537        while sorted_ids.last() == Some(&ExcerptId::max()) {
5538            sorted_ids.pop();
5539            if let Some(mapping) = self.excerpt_ids.last() {
5540                locators.push(mapping.locator.clone());
5541            }
5542        }
5543
5544        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5545        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5546            sorted_ids.next();
5547            if let Some(mapping) = self.excerpt_ids.first() {
5548                locators.push(mapping.locator.clone());
5549            }
5550        }
5551
5552        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5553        for id in sorted_ids {
5554            if cursor.seek_forward(&id, Bias::Left, &()) {
5555                locators.push(cursor.item().unwrap().locator.clone());
5556            } else {
5557                panic!("invalid excerpt id {:?}", id);
5558            }
5559        }
5560
5561        locators.sort_unstable();
5562        locators
5563    }
5564
5565    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5566        Some(self.excerpt(excerpt_id)?.buffer_id)
5567    }
5568
5569    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5570        Some(&self.excerpt(excerpt_id)?.buffer)
5571    }
5572
5573    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5574        let mut cursor = self
5575            .excerpts
5576            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5577        let locator = self.excerpt_locator_for_id(excerpt_id);
5578        if cursor.seek(&Some(locator), Bias::Left, &()) {
5579            let start = cursor.start().1.clone();
5580            let end = cursor.end(&()).1;
5581            let mut diff_transforms = self
5582                .diff_transforms
5583                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5584            diff_transforms.seek(&start, Bias::Left, &());
5585            let overshoot = start.0 - diff_transforms.start().0 .0;
5586            let start = diff_transforms.start().1 .0 + overshoot;
5587            diff_transforms.seek(&end, Bias::Right, &());
5588            let overshoot = end.0 - diff_transforms.start().0 .0;
5589            let end = diff_transforms.start().1 .0 + overshoot;
5590            Some(start..end)
5591        } else {
5592            None
5593        }
5594    }
5595
5596    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5597        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5598        let locator = self.excerpt_locator_for_id(excerpt_id);
5599        if cursor.seek(&Some(locator), Bias::Left, &()) {
5600            if let Some(excerpt) = cursor.item() {
5601                return Some(excerpt.range.context.clone());
5602            }
5603        }
5604        None
5605    }
5606
5607    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5608        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5609        let locator = self.excerpt_locator_for_id(excerpt_id);
5610        cursor.seek(&Some(locator), Bias::Left, &());
5611        if let Some(excerpt) = cursor.item() {
5612            if excerpt.id == excerpt_id {
5613                return Some(excerpt);
5614            }
5615        }
5616        None
5617    }
5618
5619    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5620    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5621        let range = range.start.to_offset(self)..range.end.to_offset(self);
5622        let mut cursor = self.cursor::<usize>();
5623        cursor.seek(&range.start);
5624
5625        let start_excerpt = cursor.excerpt()?;
5626        if range.end != range.start {
5627            cursor.seek_forward(&range.end);
5628            if cursor.excerpt()?.id != start_excerpt.id {
5629                return None;
5630            }
5631        }
5632
5633        cursor.seek_to_start_of_current_excerpt();
5634        let region = cursor.region()?;
5635        let offset = region.range.start;
5636        let buffer_offset = region.buffer_range.start;
5637        let excerpt_offset = cursor.excerpts.start().clone();
5638        Some(MultiBufferExcerpt {
5639            diff_transforms: cursor.diff_transforms,
5640            excerpt: start_excerpt,
5641            offset,
5642            buffer_offset,
5643            excerpt_offset,
5644        })
5645    }
5646
5647    pub fn selections_in_range<'a>(
5648        &'a self,
5649        range: &'a Range<Anchor>,
5650        include_local: bool,
5651    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5652        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5653        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5654        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5655        cursor.seek(start_locator, Bias::Left, &());
5656        cursor
5657            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5658            .flat_map(move |excerpt| {
5659                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5660                if excerpt.id == range.start.excerpt_id {
5661                    query_range.start = range.start.text_anchor;
5662                }
5663                if excerpt.id == range.end.excerpt_id {
5664                    query_range.end = range.end.text_anchor;
5665                }
5666
5667                excerpt
5668                    .buffer
5669                    .selections_in_range(query_range, include_local)
5670                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5671                        selections.map(move |selection| {
5672                            let mut start = Anchor {
5673                                buffer_id: Some(excerpt.buffer_id),
5674                                excerpt_id: excerpt.id,
5675                                text_anchor: selection.start,
5676                                diff_base_anchor: None,
5677                            };
5678                            let mut end = Anchor {
5679                                buffer_id: Some(excerpt.buffer_id),
5680                                excerpt_id: excerpt.id,
5681                                text_anchor: selection.end,
5682                                diff_base_anchor: None,
5683                            };
5684                            if range.start.cmp(&start, self).is_gt() {
5685                                start = range.start;
5686                            }
5687                            if range.end.cmp(&end, self).is_lt() {
5688                                end = range.end;
5689                            }
5690
5691                            (
5692                                replica_id,
5693                                line_mode,
5694                                cursor_shape,
5695                                Selection {
5696                                    id: selection.id,
5697                                    start,
5698                                    end,
5699                                    reversed: selection.reversed,
5700                                    goal: selection.goal,
5701                                },
5702                            )
5703                        })
5704                    })
5705            })
5706    }
5707
5708    pub fn show_headers(&self) -> bool {
5709        self.show_headers
5710    }
5711}
5712
5713#[cfg(any(test, feature = "test-support"))]
5714impl MultiBufferSnapshot {
5715    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5716        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5717        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5718        start..end
5719    }
5720
5721    #[cfg(any(test, feature = "test-support"))]
5722    fn check_invariants(&self) {
5723        let excerpts = self.excerpts.items(&());
5724        let excerpt_ids = self.excerpt_ids.items(&());
5725
5726        for (ix, excerpt) in excerpts.iter().enumerate() {
5727            if ix == 0 {
5728                if excerpt.locator <= Locator::min() {
5729                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5730                }
5731            } else if excerpt.locator <= excerpts[ix - 1].locator {
5732                panic!("excerpts are out-of-order: {:?}", excerpts);
5733            }
5734        }
5735
5736        for (ix, entry) in excerpt_ids.iter().enumerate() {
5737            if ix == 0 {
5738                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5739                    panic!("invalid first excerpt id {:?}", entry.id);
5740                }
5741            } else if entry.id <= excerpt_ids[ix - 1].id {
5742                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5743            }
5744        }
5745
5746        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5747            panic!(
5748                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5749                self.excerpts.summary().text.len,
5750                self.diff_transforms.summary().input,
5751                self.diff_transforms.items(&()),
5752            );
5753        }
5754
5755        let mut prev_transform: Option<&DiffTransform> = None;
5756        for item in self.diff_transforms.iter() {
5757            if let DiffTransform::BufferContent {
5758                summary,
5759                inserted_hunk_anchor,
5760            } = item
5761            {
5762                if let Some(DiffTransform::BufferContent {
5763                    inserted_hunk_anchor: prev_inserted_hunk_anchor,
5764                    ..
5765                }) = prev_transform
5766                {
5767                    if *inserted_hunk_anchor == *prev_inserted_hunk_anchor {
5768                        panic!(
5769                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_anchor:?}. transforms: {:+?}",
5770                            self.diff_transforms.items(&()));
5771                    }
5772                }
5773                if summary.len == 0 && !self.is_empty() {
5774                    panic!("empty buffer content transform");
5775                }
5776            }
5777            prev_transform = Some(item);
5778        }
5779    }
5780}
5781
5782impl<'a, D> MultiBufferCursor<'a, D>
5783where
5784    D: TextDimension + Ord + Sub<D, Output = D>,
5785{
5786    fn seek(&mut self, position: &D) {
5787        self.cached_region.take();
5788        self.diff_transforms
5789            .seek(&OutputDimension(*position), Bias::Right, &());
5790        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5791            self.diff_transforms.prev(&());
5792        }
5793
5794        let mut excerpt_position = self.diff_transforms.start().1 .0;
5795        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5796            let overshoot = *position - self.diff_transforms.start().0 .0;
5797            excerpt_position.add_assign(&overshoot);
5798        }
5799
5800        self.excerpts
5801            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
5802        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5803            self.excerpts.prev(&());
5804        }
5805    }
5806
5807    fn seek_forward(&mut self, position: &D) {
5808        self.cached_region.take();
5809        self.diff_transforms
5810            .seek_forward(&OutputDimension(*position), Bias::Right, &());
5811        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5812            self.diff_transforms.prev(&());
5813        }
5814
5815        let overshoot = *position - self.diff_transforms.start().0 .0;
5816        let mut excerpt_position = self.diff_transforms.start().1 .0;
5817        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5818            excerpt_position.add_assign(&overshoot);
5819        }
5820
5821        self.excerpts
5822            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
5823        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5824            self.excerpts.prev(&());
5825        }
5826    }
5827
5828    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
5829        self.cached_region.take();
5830        if let Some(excerpt) = self.excerpts.item() {
5831            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
5832            let position_in_excerpt = *position - excerpt_start;
5833            let mut excerpt_position = self.excerpts.start().0;
5834            excerpt_position.add_assign(&position_in_excerpt);
5835            self.diff_transforms
5836                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
5837            if self.diff_transforms.item().is_none() {
5838                self.diff_transforms.next(&());
5839            }
5840        }
5841    }
5842
5843    fn next_excerpt(&mut self) {
5844        self.excerpts.next(&());
5845        self.seek_to_start_of_current_excerpt();
5846    }
5847
5848    fn prev_excerpt(&mut self) {
5849        self.excerpts.prev(&());
5850        self.seek_to_start_of_current_excerpt();
5851    }
5852
5853    fn seek_to_start_of_current_excerpt(&mut self) {
5854        self.cached_region.take();
5855        self.diff_transforms
5856            .seek(self.excerpts.start(), Bias::Left, &());
5857        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
5858            && self.diff_transforms.start().1 < *self.excerpts.start()
5859            && self.diff_transforms.next_item().is_some()
5860        {
5861            self.diff_transforms.next(&());
5862        }
5863    }
5864
5865    fn next(&mut self) {
5866        self.cached_region.take();
5867        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
5868            cmp::Ordering::Less => self.diff_transforms.next(&()),
5869            cmp::Ordering::Greater => self.excerpts.next(&()),
5870            cmp::Ordering::Equal => {
5871                self.diff_transforms.next(&());
5872                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
5873                    || self.diff_transforms.item().is_none()
5874                {
5875                    self.excerpts.next(&());
5876                }
5877            }
5878        }
5879    }
5880
5881    fn prev(&mut self) {
5882        self.cached_region.take();
5883        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
5884            cmp::Ordering::Less => self.excerpts.prev(&()),
5885            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
5886            cmp::Ordering::Equal => {
5887                self.diff_transforms.prev(&());
5888                if self.diff_transforms.start().1 < *self.excerpts.start()
5889                    || self.diff_transforms.item().is_none()
5890                {
5891                    self.excerpts.prev(&());
5892                }
5893            }
5894        }
5895    }
5896
5897    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
5898        if self.cached_region.is_none() {
5899            self.cached_region = self.build_region();
5900        }
5901        self.cached_region.clone()
5902    }
5903
5904    fn main_buffer_position(&self) -> Option<D> {
5905        if let DiffTransform::BufferContent { .. } = self.diff_transforms.next_item()? {
5906            let excerpt = self.excerpts.item()?;
5907            let buffer = &excerpt.buffer;
5908            let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5909            let mut buffer_start = buffer_context_start;
5910            let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
5911            buffer_start.add_assign(&overshoot);
5912            Some(buffer_start)
5913        } else {
5914            None
5915        }
5916    }
5917
5918    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
5919        let excerpt = self.excerpts.item()?;
5920        match self.diff_transforms.item()? {
5921            DiffTransform::DeletedHunk {
5922                buffer_id,
5923                base_text_byte_range,
5924                has_trailing_newline,
5925                ..
5926            } => {
5927                let diff = self.diffs.get(&buffer_id)?;
5928                let buffer = &diff.base_text;
5929                let mut rope_cursor = buffer.as_rope().cursor(0);
5930                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
5931                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
5932                let mut buffer_end = buffer_start;
5933                buffer_end.add_assign(&buffer_range_len);
5934                let start = self.diff_transforms.start().0 .0;
5935                let end = self.diff_transforms.end(&()).0 .0;
5936                return Some(MultiBufferRegion {
5937                    buffer,
5938                    excerpt,
5939                    has_trailing_newline: *has_trailing_newline,
5940                    is_main_buffer: false,
5941                    is_inserted_hunk: false,
5942                    buffer_range: buffer_start..buffer_end,
5943                    range: start..end,
5944                });
5945            }
5946            DiffTransform::BufferContent {
5947                inserted_hunk_anchor,
5948                ..
5949            } => {
5950                let buffer = &excerpt.buffer;
5951                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5952
5953                let mut start = self.diff_transforms.start().0 .0;
5954                let mut buffer_start = buffer_context_start;
5955                if self.diff_transforms.start().1 < *self.excerpts.start() {
5956                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
5957                    start.add_assign(&overshoot);
5958                } else {
5959                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
5960                    buffer_start.add_assign(&overshoot);
5961                }
5962
5963                let mut end;
5964                let mut buffer_end;
5965                let has_trailing_newline;
5966                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
5967                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
5968                    end = self.diff_transforms.end(&()).0 .0;
5969                    buffer_end = buffer_context_start;
5970                    buffer_end.add_assign(&overshoot);
5971                    has_trailing_newline = false;
5972                } else {
5973                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
5974                    end = self.diff_transforms.start().0 .0;
5975                    end.add_assign(&overshoot);
5976                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
5977                    has_trailing_newline = excerpt.has_trailing_newline;
5978                };
5979
5980                Some(MultiBufferRegion {
5981                    buffer,
5982                    excerpt,
5983                    has_trailing_newline,
5984                    is_main_buffer: true,
5985                    is_inserted_hunk: inserted_hunk_anchor.is_some(),
5986                    buffer_range: buffer_start..buffer_end,
5987                    range: start..end,
5988                })
5989            }
5990        }
5991    }
5992
5993    fn excerpt(&self) -> Option<&'a Excerpt> {
5994        self.excerpts.item()
5995    }
5996}
5997
5998impl History {
5999    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6000        self.transaction_depth += 1;
6001        if self.transaction_depth == 1 {
6002            let id = self.next_transaction_id.tick();
6003            self.undo_stack.push(Transaction {
6004                id,
6005                buffer_transactions: Default::default(),
6006                first_edit_at: now,
6007                last_edit_at: now,
6008                suppress_grouping: false,
6009            });
6010            Some(id)
6011        } else {
6012            None
6013        }
6014    }
6015
6016    fn end_transaction(
6017        &mut self,
6018        now: Instant,
6019        buffer_transactions: HashMap<BufferId, TransactionId>,
6020    ) -> bool {
6021        assert_ne!(self.transaction_depth, 0);
6022        self.transaction_depth -= 1;
6023        if self.transaction_depth == 0 {
6024            if buffer_transactions.is_empty() {
6025                self.undo_stack.pop();
6026                false
6027            } else {
6028                self.redo_stack.clear();
6029                let transaction = self.undo_stack.last_mut().unwrap();
6030                transaction.last_edit_at = now;
6031                for (buffer_id, transaction_id) in buffer_transactions {
6032                    transaction
6033                        .buffer_transactions
6034                        .entry(buffer_id)
6035                        .or_insert(transaction_id);
6036                }
6037                true
6038            }
6039        } else {
6040            false
6041        }
6042    }
6043
6044    fn push_transaction<'a, T>(
6045        &mut self,
6046        buffer_transactions: T,
6047        now: Instant,
6048        cx: &Context<MultiBuffer>,
6049    ) where
6050        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6051    {
6052        assert_eq!(self.transaction_depth, 0);
6053        let transaction = Transaction {
6054            id: self.next_transaction_id.tick(),
6055            buffer_transactions: buffer_transactions
6056                .into_iter()
6057                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6058                .collect(),
6059            first_edit_at: now,
6060            last_edit_at: now,
6061            suppress_grouping: false,
6062        };
6063        if !transaction.buffer_transactions.is_empty() {
6064            self.undo_stack.push(transaction);
6065            self.redo_stack.clear();
6066        }
6067    }
6068
6069    fn finalize_last_transaction(&mut self) {
6070        if let Some(transaction) = self.undo_stack.last_mut() {
6071            transaction.suppress_grouping = true;
6072        }
6073    }
6074
6075    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6076        if let Some(ix) = self
6077            .undo_stack
6078            .iter()
6079            .rposition(|transaction| transaction.id == transaction_id)
6080        {
6081            Some(self.undo_stack.remove(ix))
6082        } else if let Some(ix) = self
6083            .redo_stack
6084            .iter()
6085            .rposition(|transaction| transaction.id == transaction_id)
6086        {
6087            Some(self.redo_stack.remove(ix))
6088        } else {
6089            None
6090        }
6091    }
6092
6093    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6094        self.undo_stack
6095            .iter()
6096            .find(|transaction| transaction.id == transaction_id)
6097            .or_else(|| {
6098                self.redo_stack
6099                    .iter()
6100                    .find(|transaction| transaction.id == transaction_id)
6101            })
6102    }
6103
6104    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6105        self.undo_stack
6106            .iter_mut()
6107            .find(|transaction| transaction.id == transaction_id)
6108            .or_else(|| {
6109                self.redo_stack
6110                    .iter_mut()
6111                    .find(|transaction| transaction.id == transaction_id)
6112            })
6113    }
6114
6115    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6116        assert_eq!(self.transaction_depth, 0);
6117        if let Some(transaction) = self.undo_stack.pop() {
6118            self.redo_stack.push(transaction);
6119            self.redo_stack.last_mut()
6120        } else {
6121            None
6122        }
6123    }
6124
6125    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6126        assert_eq!(self.transaction_depth, 0);
6127        if let Some(transaction) = self.redo_stack.pop() {
6128            self.undo_stack.push(transaction);
6129            self.undo_stack.last_mut()
6130        } else {
6131            None
6132        }
6133    }
6134
6135    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6136        let ix = self
6137            .undo_stack
6138            .iter()
6139            .rposition(|transaction| transaction.id == transaction_id)?;
6140        let transaction = self.undo_stack.remove(ix);
6141        self.redo_stack.push(transaction);
6142        self.redo_stack.last()
6143    }
6144
6145    fn group(&mut self) -> Option<TransactionId> {
6146        let mut count = 0;
6147        let mut transactions = self.undo_stack.iter();
6148        if let Some(mut transaction) = transactions.next_back() {
6149            while let Some(prev_transaction) = transactions.next_back() {
6150                if !prev_transaction.suppress_grouping
6151                    && transaction.first_edit_at - prev_transaction.last_edit_at
6152                        <= self.group_interval
6153                {
6154                    transaction = prev_transaction;
6155                    count += 1;
6156                } else {
6157                    break;
6158                }
6159            }
6160        }
6161        self.group_trailing(count)
6162    }
6163
6164    fn group_until(&mut self, transaction_id: TransactionId) {
6165        let mut count = 0;
6166        for transaction in self.undo_stack.iter().rev() {
6167            if transaction.id == transaction_id {
6168                self.group_trailing(count);
6169                break;
6170            } else if transaction.suppress_grouping {
6171                break;
6172            } else {
6173                count += 1;
6174            }
6175        }
6176    }
6177
6178    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6179        let new_len = self.undo_stack.len() - n;
6180        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6181        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6182            if let Some(transaction) = transactions_to_merge.last() {
6183                last_transaction.last_edit_at = transaction.last_edit_at;
6184            }
6185            for to_merge in transactions_to_merge {
6186                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6187                    last_transaction
6188                        .buffer_transactions
6189                        .entry(*buffer_id)
6190                        .or_insert(*transaction_id);
6191                }
6192            }
6193        }
6194
6195        self.undo_stack.truncate(new_len);
6196        self.undo_stack.last().map(|t| t.id)
6197    }
6198}
6199
6200impl Excerpt {
6201    fn new(
6202        id: ExcerptId,
6203        locator: Locator,
6204        buffer_id: BufferId,
6205        buffer: BufferSnapshot,
6206        range: ExcerptRange<text::Anchor>,
6207        has_trailing_newline: bool,
6208    ) -> Self {
6209        Excerpt {
6210            id,
6211            locator,
6212            max_buffer_row: range.context.end.to_point(&buffer).row,
6213            text_summary: buffer
6214                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6215            buffer_id,
6216            buffer,
6217            range,
6218            has_trailing_newline,
6219        }
6220    }
6221
6222    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6223        let content_start = self.range.context.start.to_offset(&self.buffer);
6224        let chunks_start = content_start + range.start;
6225        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6226
6227        let footer_height = if self.has_trailing_newline
6228            && range.start <= self.text_summary.len
6229            && range.end > self.text_summary.len
6230        {
6231            1
6232        } else {
6233            0
6234        };
6235
6236        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6237
6238        ExcerptChunks {
6239            excerpt_id: self.id,
6240            content_chunks,
6241            footer_height,
6242        }
6243    }
6244
6245    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6246        let content_start = self.range.context.start.to_offset(&self.buffer);
6247        let chunks_start = content_start + range.start;
6248        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6249        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6250        excerpt_chunks.footer_height = if self.has_trailing_newline
6251            && range.start <= self.text_summary.len
6252            && range.end > self.text_summary.len
6253        {
6254            1
6255        } else {
6256            0
6257        };
6258    }
6259
6260    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6261        if text_anchor
6262            .cmp(&self.range.context.start, &self.buffer)
6263            .is_lt()
6264        {
6265            self.range.context.start
6266        } else if text_anchor
6267            .cmp(&self.range.context.end, &self.buffer)
6268            .is_gt()
6269        {
6270            self.range.context.end
6271        } else {
6272            text_anchor
6273        }
6274    }
6275
6276    fn contains(&self, anchor: &Anchor) -> bool {
6277        Some(self.buffer_id) == anchor.buffer_id
6278            && self
6279                .range
6280                .context
6281                .start
6282                .cmp(&anchor.text_anchor, &self.buffer)
6283                .is_le()
6284            && self
6285                .range
6286                .context
6287                .end
6288                .cmp(&anchor.text_anchor, &self.buffer)
6289                .is_ge()
6290    }
6291
6292    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6293    fn buffer_start_offset(&self) -> usize {
6294        self.range.context.start.to_offset(&self.buffer)
6295    }
6296
6297    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6298    fn buffer_end_offset(&self) -> usize {
6299        self.buffer_start_offset() + self.text_summary.len
6300    }
6301}
6302
6303impl<'a> MultiBufferExcerpt<'a> {
6304    pub fn id(&self) -> ExcerptId {
6305        self.excerpt.id
6306    }
6307
6308    pub fn buffer_id(&self) -> BufferId {
6309        self.excerpt.buffer_id
6310    }
6311
6312    pub fn start_anchor(&self) -> Anchor {
6313        Anchor {
6314            buffer_id: Some(self.excerpt.buffer_id),
6315            excerpt_id: self.excerpt.id,
6316            text_anchor: self.excerpt.range.context.start,
6317            diff_base_anchor: None,
6318        }
6319    }
6320
6321    pub fn end_anchor(&self) -> Anchor {
6322        Anchor {
6323            buffer_id: Some(self.excerpt.buffer_id),
6324            excerpt_id: self.excerpt.id,
6325            text_anchor: self.excerpt.range.context.end,
6326            diff_base_anchor: None,
6327        }
6328    }
6329
6330    pub fn buffer(&self) -> &'a BufferSnapshot {
6331        &self.excerpt.buffer
6332    }
6333
6334    pub fn buffer_range(&self) -> Range<usize> {
6335        self.buffer_offset
6336            ..self
6337                .excerpt
6338                .range
6339                .context
6340                .end
6341                .to_offset(&self.excerpt.buffer.text)
6342    }
6343
6344    pub fn start_offset(&self) -> usize {
6345        self.offset
6346    }
6347
6348    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6349    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6350        self.map_range_to_buffer(offset..offset).start
6351    }
6352
6353    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6354    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6355        self.diff_transforms
6356            .seek(&OutputDimension(range.start), Bias::Right, &());
6357        let start = self.map_offset_to_buffer_internal(range.start);
6358        let end = if range.end > range.start {
6359            self.diff_transforms
6360                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6361            self.map_offset_to_buffer_internal(range.end)
6362        } else {
6363            start
6364        };
6365        start..end
6366    }
6367
6368    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6369        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6370        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6371            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6372        };
6373        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6374        self.buffer_offset + offset_in_excerpt
6375    }
6376
6377    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6378    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6379        self.map_range_from_buffer(buffer_offset..buffer_offset)
6380            .start
6381    }
6382
6383    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6384    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6385        let overshoot = buffer_range.start - self.buffer_offset;
6386        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6387        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6388        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6389        let start = self.diff_transforms.start().0 .0 + overshoot;
6390
6391        let end = if buffer_range.end > buffer_range.start {
6392            let overshoot = buffer_range.end - self.buffer_offset;
6393            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6394            self.diff_transforms
6395                .seek_forward(&excerpt_offset, Bias::Right, &());
6396            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6397            self.diff_transforms.start().0 .0 + overshoot
6398        } else {
6399            start
6400        };
6401
6402        start..end
6403    }
6404
6405    /// Returns true if the entirety of the given range is in the buffer's excerpt
6406    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6407        range.start >= self.excerpt.buffer_start_offset()
6408            && range.end <= self.excerpt.buffer_end_offset()
6409    }
6410
6411    pub fn max_buffer_row(&self) -> u32 {
6412        self.excerpt.max_buffer_row
6413    }
6414}
6415
6416impl ExcerptId {
6417    pub fn min() -> Self {
6418        Self(0)
6419    }
6420
6421    pub fn max() -> Self {
6422        Self(usize::MAX)
6423    }
6424
6425    pub fn to_proto(&self) -> u64 {
6426        self.0 as _
6427    }
6428
6429    pub fn from_proto(proto: u64) -> Self {
6430        Self(proto as _)
6431    }
6432
6433    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6434        let a = snapshot.excerpt_locator_for_id(*self);
6435        let b = snapshot.excerpt_locator_for_id(*other);
6436        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6437    }
6438}
6439
6440impl From<ExcerptId> for usize {
6441    fn from(val: ExcerptId) -> Self {
6442        val.0
6443    }
6444}
6445
6446impl fmt::Debug for Excerpt {
6447    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6448        f.debug_struct("Excerpt")
6449            .field("id", &self.id)
6450            .field("locator", &self.locator)
6451            .field("buffer_id", &self.buffer_id)
6452            .field("range", &self.range)
6453            .field("text_summary", &self.text_summary)
6454            .field("has_trailing_newline", &self.has_trailing_newline)
6455            .finish()
6456    }
6457}
6458
6459impl sum_tree::Item for Excerpt {
6460    type Summary = ExcerptSummary;
6461
6462    fn summary(&self, _cx: &()) -> Self::Summary {
6463        let mut text = self.text_summary;
6464        if self.has_trailing_newline {
6465            text += TextSummary::from("\n");
6466        }
6467        ExcerptSummary {
6468            excerpt_id: self.id,
6469            excerpt_locator: self.locator.clone(),
6470            widest_line_number: self.max_buffer_row,
6471            text,
6472        }
6473    }
6474}
6475
6476impl sum_tree::Item for ExcerptIdMapping {
6477    type Summary = ExcerptId;
6478
6479    fn summary(&self, _cx: &()) -> Self::Summary {
6480        self.id
6481    }
6482}
6483
6484impl sum_tree::KeyedItem for ExcerptIdMapping {
6485    type Key = ExcerptId;
6486
6487    fn key(&self) -> Self::Key {
6488        self.id
6489    }
6490}
6491
6492impl DiffTransform {
6493    fn hunk_anchor(&self) -> Option<(ExcerptId, text::Anchor)> {
6494        match self {
6495            DiffTransform::DeletedHunk { hunk_anchor, .. } => Some(*hunk_anchor),
6496            DiffTransform::BufferContent {
6497                inserted_hunk_anchor,
6498                ..
6499            } => *inserted_hunk_anchor,
6500        }
6501    }
6502}
6503
6504impl sum_tree::Item for DiffTransform {
6505    type Summary = DiffTransformSummary;
6506
6507    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6508        match self {
6509            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6510                input: *summary,
6511                output: *summary,
6512            },
6513            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6514                input: TextSummary::default(),
6515                output: *summary,
6516            },
6517        }
6518    }
6519}
6520
6521impl DiffTransformSummary {
6522    fn excerpt_len(&self) -> ExcerptOffset {
6523        ExcerptOffset::new(self.input.len)
6524    }
6525}
6526
6527impl sum_tree::Summary for DiffTransformSummary {
6528    type Context = ();
6529
6530    fn zero(_: &Self::Context) -> Self {
6531        DiffTransformSummary {
6532            input: TextSummary::default(),
6533            output: TextSummary::default(),
6534        }
6535    }
6536
6537    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6538        self.input += &summary.input;
6539        self.output += &summary.output;
6540    }
6541}
6542
6543impl sum_tree::Summary for ExcerptId {
6544    type Context = ();
6545
6546    fn zero(_cx: &()) -> Self {
6547        Default::default()
6548    }
6549
6550    fn add_summary(&mut self, other: &Self, _: &()) {
6551        *self = *other;
6552    }
6553}
6554
6555impl sum_tree::Summary for ExcerptSummary {
6556    type Context = ();
6557
6558    fn zero(_cx: &()) -> Self {
6559        Default::default()
6560    }
6561
6562    fn add_summary(&mut self, summary: &Self, _: &()) {
6563        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6564        self.excerpt_locator = summary.excerpt_locator.clone();
6565        self.text.add_summary(&summary.text, &());
6566        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6567    }
6568}
6569
6570impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6571    fn zero(_cx: &()) -> Self {
6572        Default::default()
6573    }
6574
6575    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6576        self.value += summary.text.len;
6577    }
6578}
6579
6580impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6581    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6582        Ord::cmp(&self.value, &cursor_location.text.len)
6583    }
6584}
6585
6586impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6587    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6588        Ord::cmp(&Some(self), cursor_location)
6589    }
6590}
6591
6592impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
6593    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6594        Ord::cmp(self, &cursor_location.excerpt_locator)
6595    }
6596}
6597
6598impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6599    fn zero(_cx: &()) -> Self {
6600        Default::default()
6601    }
6602
6603    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6604        self.value += summary.text.lines;
6605    }
6606}
6607
6608impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6609    for ExcerptDimension<D>
6610{
6611    fn zero(_: &()) -> Self {
6612        ExcerptDimension(D::default())
6613    }
6614
6615    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6616        self.0.add_assign(&D::from_text_summary(&summary.text))
6617    }
6618}
6619
6620impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6621    fn zero(_cx: &()) -> Self {
6622        Default::default()
6623    }
6624
6625    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6626        *self = Some(&summary.excerpt_locator);
6627    }
6628}
6629
6630impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6631    fn zero(_cx: &()) -> Self {
6632        Default::default()
6633    }
6634
6635    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6636        *self = Some(summary.excerpt_id);
6637    }
6638}
6639
6640#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6641struct ExcerptDimension<T>(T);
6642
6643#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6644struct OutputDimension<T>(T);
6645
6646impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6647    fn zero(_: &()) -> Self {
6648        ExcerptOffset::new(0)
6649    }
6650
6651    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6652        self.value += summary.input.len;
6653    }
6654}
6655
6656impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6657    fn zero(_: &()) -> Self {
6658        ExcerptPoint::new(0, 0)
6659    }
6660
6661    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6662        self.value += summary.input.lines;
6663    }
6664}
6665
6666impl<'a, D: TextDimension + Ord>
6667    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransformSummary> for ExcerptDimension<D>
6668{
6669    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6670        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6671    }
6672}
6673
6674impl<'a, D: TextDimension + Ord>
6675    sum_tree::SeekTarget<'a, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6676    for ExcerptDimension<D>
6677{
6678    fn cmp(
6679        &self,
6680        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6681        _: &(),
6682    ) -> cmp::Ordering {
6683        Ord::cmp(&self.0, &cursor_location.1 .0)
6684    }
6685}
6686
6687impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6688    fn zero(_: &()) -> Self {
6689        ExcerptDimension(D::default())
6690    }
6691
6692    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6693        self.0.add_assign(&D::from_text_summary(&summary.input))
6694    }
6695}
6696
6697impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6698    fn zero(_: &()) -> Self {
6699        OutputDimension(D::default())
6700    }
6701
6702    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6703        self.0.add_assign(&D::from_text_summary(&summary.output))
6704    }
6705}
6706
6707impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6708    fn zero(_: &()) -> Self {
6709        TextSummary::default()
6710    }
6711
6712    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6713        *self += summary.output
6714    }
6715}
6716
6717impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6718    fn zero(_: &()) -> Self {
6719        0
6720    }
6721
6722    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6723        *self += summary.output.len
6724    }
6725}
6726
6727impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6728    fn zero(_: &()) -> Self {
6729        Point::new(0, 0)
6730    }
6731
6732    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6733        *self += summary.output.lines
6734    }
6735}
6736
6737impl<'a> MultiBufferRows<'a> {
6738    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6739        self.point = Point::new(row, 0);
6740        self.cursor.seek(&self.point);
6741    }
6742}
6743
6744impl<'a> Iterator for MultiBufferRows<'a> {
6745    type Item = RowInfo;
6746
6747    fn next(&mut self) -> Option<Self::Item> {
6748        if self.is_empty && self.point.row == 0 {
6749            self.point += Point::new(1, 0);
6750            return Some(RowInfo {
6751                buffer_row: Some(0),
6752                multibuffer_row: Some(MultiBufferRow(0)),
6753                diff_status: None,
6754            });
6755        }
6756
6757        let mut region = self.cursor.region()?;
6758        while self.point >= region.range.end {
6759            self.cursor.next();
6760            if let Some(next_region) = self.cursor.region() {
6761                region = next_region;
6762            } else {
6763                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
6764                    let multibuffer_row = MultiBufferRow(self.point.row);
6765                    self.point += Point::new(1, 0);
6766                    let last_excerpt = self
6767                        .cursor
6768                        .excerpts
6769                        .item()
6770                        .or(self.cursor.excerpts.prev_item())?;
6771                    let last_row = last_excerpt
6772                        .range
6773                        .context
6774                        .end
6775                        .to_point(&last_excerpt.buffer)
6776                        .row;
6777                    return Some(RowInfo {
6778                        buffer_row: Some(last_row),
6779                        multibuffer_row: Some(multibuffer_row),
6780                        diff_status: None,
6781                    });
6782                } else {
6783                    return None;
6784                }
6785            };
6786        }
6787
6788        let overshoot = self.point - region.range.start;
6789        let buffer_point = region.buffer_range.start + overshoot;
6790        let result = Some(RowInfo {
6791            buffer_row: Some(buffer_point.row),
6792            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6793            diff_status: if region.is_inserted_hunk && self.point < region.range.end {
6794                Some(DiffHunkStatus::Added)
6795            } else if !region.is_main_buffer {
6796                Some(DiffHunkStatus::Removed)
6797            } else {
6798                None
6799            },
6800        });
6801        self.point += Point::new(1, 0);
6802        result
6803    }
6804}
6805
6806impl<'a> MultiBufferChunks<'a> {
6807    pub fn offset(&self) -> usize {
6808        self.range.start
6809    }
6810
6811    pub fn seek(&mut self, range: Range<usize>) {
6812        self.diff_transforms.seek(&range.end, Bias::Right, &());
6813        let mut excerpt_end = self.diff_transforms.start().1;
6814        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6815            let overshoot = range.end - self.diff_transforms.start().0;
6816            excerpt_end.value += overshoot;
6817        }
6818
6819        self.diff_transforms.seek(&range.start, Bias::Right, &());
6820        let mut excerpt_start = self.diff_transforms.start().1;
6821        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6822            let overshoot = range.start - self.diff_transforms.start().0;
6823            excerpt_start.value += overshoot;
6824        }
6825
6826        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6827        self.buffer_chunk.take();
6828        self.range = range;
6829    }
6830
6831    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6832        self.excerpt_offset_range = new_range.clone();
6833        self.excerpts.seek(&new_range.start, Bias::Right, &());
6834        if let Some(excerpt) = self.excerpts.item() {
6835            let excerpt_start = *self.excerpts.start();
6836            if let Some(excerpt_chunks) = self
6837                .excerpt_chunks
6838                .as_mut()
6839                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6840            {
6841                excerpt.seek_chunks(
6842                    excerpt_chunks,
6843                    (self.excerpt_offset_range.start - excerpt_start).value
6844                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6845                );
6846            } else {
6847                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6848                    (self.excerpt_offset_range.start - excerpt_start).value
6849                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6850                    self.language_aware,
6851                ));
6852            }
6853        } else {
6854            self.excerpt_chunks = None;
6855        }
6856    }
6857
6858    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6859        loop {
6860            if self.excerpt_offset_range.is_empty() {
6861                return None;
6862            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6863                self.excerpt_offset_range.start.value += chunk.text.len();
6864                return Some(chunk);
6865            } else {
6866                self.excerpts.next(&());
6867                let excerpt = self.excerpts.item()?;
6868                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6869                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6870                    self.language_aware,
6871                ));
6872            }
6873        }
6874    }
6875}
6876
6877impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6878    type Item = &'a str;
6879
6880    fn next(&mut self) -> Option<Self::Item> {
6881        let mut region = self.cursor.region()?;
6882        if self.offset == region.range.start {
6883            self.cursor.prev();
6884            region = self.cursor.region()?;
6885            let start_overshoot = self.start.saturating_sub(region.range.start);
6886            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6887                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6888            ));
6889        }
6890
6891        if self.offset == region.range.end && region.has_trailing_newline {
6892            self.offset -= 1;
6893            Some("\n")
6894        } else {
6895            let chunk = self.current_chunks.as_mut().unwrap().next().unwrap();
6896            self.offset -= chunk.len();
6897            Some(chunk)
6898        }
6899    }
6900}
6901
6902impl<'a> Iterator for MultiBufferChunks<'a> {
6903    type Item = Chunk<'a>;
6904
6905    fn next(&mut self) -> Option<Chunk<'a>> {
6906        if self.range.start >= self.range.end {
6907            return None;
6908        }
6909        if self.range.start == self.diff_transforms.end(&()).0 {
6910            self.diff_transforms.next(&());
6911        }
6912
6913        let diff_transform_start = self.diff_transforms.start().0;
6914        let diff_transform_end = self.diff_transforms.end(&()).0;
6915        debug_assert!(self.range.start < diff_transform_end);
6916
6917        let diff_transform = self.diff_transforms.item()?;
6918        match diff_transform {
6919            DiffTransform::BufferContent { .. } => {
6920                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6921                    chunk
6922                } else {
6923                    let chunk = self.next_excerpt_chunk().unwrap();
6924                    self.buffer_chunk.insert(chunk)
6925                };
6926
6927                let chunk_end = self.range.start + chunk.text.len();
6928                let diff_transform_end = diff_transform_end.min(self.range.end);
6929
6930                if diff_transform_end < chunk_end {
6931                    let (before, after) =
6932                        chunk.text.split_at(diff_transform_end - self.range.start);
6933                    self.range.start = diff_transform_end;
6934                    chunk.text = after;
6935                    Some(Chunk {
6936                        text: before,
6937                        ..chunk.clone()
6938                    })
6939                } else {
6940                    self.range.start = chunk_end;
6941                    self.buffer_chunk.take()
6942                }
6943            }
6944            DiffTransform::DeletedHunk {
6945                buffer_id,
6946                base_text_byte_range,
6947                has_trailing_newline,
6948                ..
6949            } => {
6950                let base_text_start =
6951                    base_text_byte_range.start + self.range.start - diff_transform_start;
6952                let base_text_end =
6953                    base_text_byte_range.start + self.range.end - diff_transform_start;
6954                let base_text_end = base_text_end.min(base_text_byte_range.end);
6955
6956                let mut chunks = if let Some((_, mut chunks)) = self
6957                    .diff_base_chunks
6958                    .take()
6959                    .filter(|(id, _)| id == buffer_id)
6960                {
6961                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
6962                    {
6963                        chunks.seek(base_text_start..base_text_end);
6964                    }
6965                    chunks
6966                } else {
6967                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text;
6968                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
6969                };
6970
6971                let chunk = if let Some(chunk) = chunks.next() {
6972                    self.range.start += chunk.text.len();
6973                    self.diff_base_chunks = Some((*buffer_id, chunks));
6974                    chunk
6975                } else {
6976                    debug_assert!(has_trailing_newline);
6977                    self.range.start += "\n".len();
6978                    Chunk {
6979                        text: "\n",
6980                        ..Default::default()
6981                    }
6982                };
6983                Some(chunk)
6984            }
6985        }
6986    }
6987}
6988
6989impl<'a> MultiBufferBytes<'a> {
6990    fn consume(&mut self, len: usize) {
6991        self.range.start += len;
6992        self.chunk = &self.chunk[len..];
6993
6994        if !self.range.is_empty() && self.chunk.is_empty() {
6995            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
6996                self.chunk = chunk;
6997            } else if self.has_trailing_newline {
6998                self.has_trailing_newline = false;
6999                self.chunk = b"\n";
7000            } else {
7001                self.cursor.next();
7002                if let Some(region) = self.cursor.region() {
7003                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7004                        region.buffer_range.start
7005                            ..(region.buffer_range.start + self.range.end - region.range.start)
7006                                .min(region.buffer_range.end),
7007                    );
7008                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7009                    self.excerpt_bytes = Some(excerpt_bytes);
7010                    self.has_trailing_newline =
7011                        region.has_trailing_newline && self.range.end >= region.range.end;
7012                    if self.chunk.is_empty() && self.has_trailing_newline {
7013                        self.has_trailing_newline = false;
7014                        self.chunk = b"\n";
7015                    }
7016                }
7017            }
7018        }
7019    }
7020}
7021
7022impl<'a> Iterator for MultiBufferBytes<'a> {
7023    type Item = &'a [u8];
7024
7025    fn next(&mut self) -> Option<Self::Item> {
7026        let chunk = self.chunk;
7027        if chunk.is_empty() {
7028            None
7029        } else {
7030            self.consume(chunk.len());
7031            Some(chunk)
7032        }
7033    }
7034}
7035
7036impl<'a> io::Read for MultiBufferBytes<'a> {
7037    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7038        let len = cmp::min(buf.len(), self.chunk.len());
7039        buf[..len].copy_from_slice(&self.chunk[..len]);
7040        if len > 0 {
7041            self.consume(len);
7042        }
7043        Ok(len)
7044    }
7045}
7046
7047impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
7048    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7049        let len = cmp::min(buf.len(), self.chunk.len());
7050        buf[..len].copy_from_slice(&self.chunk[..len]);
7051        buf[..len].reverse();
7052        if len > 0 {
7053            self.range.end -= len;
7054            self.chunk = &self.chunk[..self.chunk.len() - len];
7055            if !self.range.is_empty() && self.chunk.is_empty() {
7056                if let Some(chunk) = self.chunks.next() {
7057                    self.chunk = chunk.as_bytes();
7058                }
7059            }
7060        }
7061        Ok(len)
7062    }
7063}
7064
7065impl<'a> Iterator for ExcerptChunks<'a> {
7066    type Item = Chunk<'a>;
7067
7068    fn next(&mut self) -> Option<Self::Item> {
7069        if let Some(chunk) = self.content_chunks.next() {
7070            return Some(chunk);
7071        }
7072
7073        if self.footer_height > 0 {
7074            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7075            self.footer_height = 0;
7076            return Some(Chunk {
7077                text,
7078                ..Default::default()
7079            });
7080        }
7081
7082        None
7083    }
7084}
7085
7086impl ToOffset for Point {
7087    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7088        snapshot.point_to_offset(*self)
7089    }
7090}
7091
7092impl ToOffset for usize {
7093    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7094        assert!(*self <= snapshot.len(), "offset is out of range");
7095        *self
7096    }
7097}
7098
7099impl ToOffset for OffsetUtf16 {
7100    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7101        snapshot.offset_utf16_to_offset(*self)
7102    }
7103}
7104
7105impl ToOffset for PointUtf16 {
7106    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7107        snapshot.point_utf16_to_offset(*self)
7108    }
7109}
7110
7111impl ToOffsetUtf16 for OffsetUtf16 {
7112    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7113        *self
7114    }
7115}
7116
7117impl ToOffsetUtf16 for usize {
7118    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7119        snapshot.offset_to_offset_utf16(*self)
7120    }
7121}
7122
7123impl ToPoint for usize {
7124    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7125        snapshot.offset_to_point(*self)
7126    }
7127}
7128
7129impl ToPoint for Point {
7130    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7131        *self
7132    }
7133}
7134
7135impl ToPointUtf16 for usize {
7136    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7137        snapshot.offset_to_point_utf16(*self)
7138    }
7139}
7140
7141impl ToPointUtf16 for Point {
7142    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7143        snapshot.point_to_point_utf16(*self)
7144    }
7145}
7146
7147impl ToPointUtf16 for PointUtf16 {
7148    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7149        *self
7150    }
7151}
7152
7153impl From<ExcerptId> for EntityId {
7154    fn from(id: ExcerptId) -> Self {
7155        EntityId::from(id.0 as u64)
7156    }
7157}
7158
7159pub fn build_excerpt_ranges<T>(
7160    buffer: &BufferSnapshot,
7161    ranges: &[Range<T>],
7162    context_line_count: u32,
7163) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7164where
7165    T: text::ToPoint,
7166{
7167    let max_point = buffer.max_point();
7168    let mut range_counts = Vec::new();
7169    let mut excerpt_ranges = Vec::new();
7170    let mut range_iter = ranges
7171        .iter()
7172        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7173        .peekable();
7174    while let Some(range) = range_iter.next() {
7175        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7176        let row = (range.end.row + context_line_count).min(max_point.row);
7177        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7178
7179        let mut ranges_in_excerpt = 1;
7180
7181        while let Some(next_range) = range_iter.peek() {
7182            if next_range.start.row <= excerpt_end.row + context_line_count {
7183                let row = (next_range.end.row + context_line_count).min(max_point.row);
7184                excerpt_end = Point::new(row, buffer.line_len(row));
7185
7186                ranges_in_excerpt += 1;
7187                range_iter.next();
7188            } else {
7189                break;
7190            }
7191        }
7192
7193        excerpt_ranges.push(ExcerptRange {
7194            context: excerpt_start..excerpt_end,
7195            primary: Some(range),
7196        });
7197        range_counts.push(ranges_in_excerpt);
7198    }
7199
7200    (excerpt_ranges, range_counts)
7201}