multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use clock::ReplicaId;
  11use collections::{BTreeMap, Bound, HashMap, HashSet};
  12use diff::{BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkStatus};
  13use futures::{channel::mpsc, SinkExt};
  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};
  24
  25use rope::DimensionPair;
  26use smallvec::SmallVec;
  27use smol::future::yield_now;
  28use std::{
  29    any::type_name,
  30    borrow::Cow,
  31    cell::{Ref, RefCell},
  32    cmp, fmt,
  33    future::Future,
  34    io,
  35    iter::{self, FromIterator},
  36    mem,
  37    ops::{Range, RangeBounds, Sub},
  38    path::Path,
  39    str,
  40    sync::Arc,
  41    time::{Duration, Instant},
  42};
  43use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  44use text::{
  45    locator::Locator,
  46    subscription::{Subscription, Topic},
  47    BufferId, Edit, LineIndent, TextSummary,
  48};
  49use theme::SyntaxTheme;
  50use util::post_inc;
  51
  52#[cfg(any(test, feature = "test-support"))]
  53use gpui::AppContext as _;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    diffs: HashMap<BufferId, DiffState>,
  72    all_diff_hunks_expanded: bool,
  73    subscriptions: Topic,
  74    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  75    singleton: bool,
  76    history: History,
  77    title: Option<String>,
  78    capability: Capability,
  79}
  80
  81#[derive(Clone, Debug, PartialEq, Eq)]
  82pub enum Event {
  83    ExcerptsAdded {
  84        buffer: Entity<Buffer>,
  85        predecessor: ExcerptId,
  86        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  87    },
  88    ExcerptsRemoved {
  89        ids: Vec<ExcerptId>,
  90    },
  91    ExcerptsExpanded {
  92        ids: Vec<ExcerptId>,
  93    },
  94    ExcerptsEdited {
  95        ids: Vec<ExcerptId>,
  96    },
  97    DiffHunksToggled,
  98    Edited {
  99        singleton_buffer_edited: bool,
 100        edited_buffer: Option<Entity<Buffer>>,
 101    },
 102    TransactionUndone {
 103        transaction_id: TransactionId,
 104    },
 105    Reloaded,
 106    ReloadNeeded,
 107
 108    LanguageChanged(BufferId),
 109    CapabilityChanged,
 110    Reparsed(BufferId),
 111    Saved,
 112    FileHandleChanged,
 113    Closed,
 114    Discarded,
 115    DirtyChanged,
 116    DiagnosticsUpdated,
 117}
 118
 119/// A diff hunk, representing a range of consequent lines in a multibuffer.
 120#[derive(Debug, Clone, PartialEq, Eq)]
 121pub struct MultiBufferDiffHunk {
 122    /// The row range in the multibuffer where this diff hunk appears.
 123    pub row_range: Range<MultiBufferRow>,
 124    /// The buffer ID that this hunk belongs to.
 125    pub buffer_id: BufferId,
 126    /// The range of the underlying buffer that this hunk corresponds to.
 127    pub buffer_range: Range<text::Anchor>,
 128    /// The excerpt that contains the diff hunk.
 129    pub excerpt_id: ExcerptId,
 130    /// The range within the buffer's diff base that this hunk corresponds to.
 131    pub diff_base_byte_range: Range<usize>,
 132}
 133
 134impl MultiBufferDiffHunk {
 135    pub fn status(&self) -> DiffHunkStatus {
 136        if self.buffer_range.start == self.buffer_range.end {
 137            DiffHunkStatus::Removed
 138        } else if self.diff_base_byte_range.is_empty() {
 139            DiffHunkStatus::Added
 140        } else {
 141            DiffHunkStatus::Modified
 142        }
 143    }
 144}
 145
 146#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 147pub struct PathKey(String);
 148
 149impl PathKey {
 150    pub fn namespaced(namespace: &str, path: &Path) -> Self {
 151        Self(format!("{}/{}", namespace, path.to_string_lossy()))
 152    }
 153}
 154
 155pub type MultiBufferPoint = Point;
 156type ExcerptOffset = TypedOffset<Excerpt>;
 157type ExcerptPoint = TypedPoint<Excerpt>;
 158
 159#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 160#[serde(transparent)]
 161pub struct MultiBufferRow(pub u32);
 162
 163impl MultiBufferRow {
 164    pub const MIN: Self = Self(0);
 165    pub const MAX: Self = Self(u32::MAX);
 166}
 167
 168impl std::ops::Add<usize> for MultiBufferRow {
 169    type Output = Self;
 170
 171    fn add(self, rhs: usize) -> Self::Output {
 172        MultiBufferRow(self.0 + rhs as u32)
 173    }
 174}
 175
 176#[derive(Clone)]
 177struct History {
 178    next_transaction_id: TransactionId,
 179    undo_stack: Vec<Transaction>,
 180    redo_stack: Vec<Transaction>,
 181    transaction_depth: usize,
 182    group_interval: Duration,
 183}
 184
 185#[derive(Clone)]
 186struct Transaction {
 187    id: TransactionId,
 188    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 189    first_edit_at: Instant,
 190    last_edit_at: Instant,
 191    suppress_grouping: bool,
 192}
 193
 194pub trait ToOffset: 'static + fmt::Debug {
 195    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 196}
 197
 198pub trait ToOffsetUtf16: 'static + fmt::Debug {
 199    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 200}
 201
 202pub trait ToPoint: 'static + fmt::Debug {
 203    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 204}
 205
 206pub trait ToPointUtf16: 'static + fmt::Debug {
 207    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 208}
 209
 210struct BufferState {
 211    buffer: Entity<Buffer>,
 212    last_version: clock::Global,
 213    last_non_text_state_update_count: usize,
 214    excerpts: Vec<Locator>,
 215    _subscriptions: [gpui::Subscription; 2],
 216}
 217
 218struct DiffState {
 219    diff: Entity<BufferDiff>,
 220    _subscription: gpui::Subscription,
 221}
 222
 223impl DiffState {
 224    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 225        DiffState {
 226            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 227                BufferDiffEvent::DiffChanged { changed_range } => {
 228                    this.buffer_diff_changed(diff, changed_range.clone(), cx)
 229                }
 230                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 231            }),
 232            diff,
 233        }
 234    }
 235}
 236
 237/// The contents of a [`MultiBuffer`] at a single point in time.
 238#[derive(Clone, Default)]
 239pub struct MultiBufferSnapshot {
 240    singleton: bool,
 241    excerpts: SumTree<Excerpt>,
 242    excerpt_ids: SumTree<ExcerptIdMapping>,
 243    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 244    pub diff_transforms: SumTree<DiffTransform>,
 245    trailing_excerpt_update_count: usize,
 246    non_text_state_update_count: usize,
 247    edit_count: usize,
 248    is_dirty: bool,
 249    has_deleted_file: bool,
 250    has_conflict: bool,
 251    show_headers: bool,
 252}
 253
 254#[derive(Debug, Clone)]
 255pub enum DiffTransform {
 256    BufferContent {
 257        summary: TextSummary,
 258        inserted_hunk_anchor: Option<(ExcerptId, text::Anchor)>,
 259    },
 260    DeletedHunk {
 261        summary: TextSummary,
 262        buffer_id: BufferId,
 263        hunk_anchor: (ExcerptId, text::Anchor),
 264        base_text_byte_range: Range<usize>,
 265        has_trailing_newline: bool,
 266    },
 267}
 268
 269#[derive(Clone)]
 270pub struct ExcerptInfo {
 271    pub id: ExcerptId,
 272    pub buffer: BufferSnapshot,
 273    pub buffer_id: BufferId,
 274    pub range: ExcerptRange<text::Anchor>,
 275    pub end_row: MultiBufferRow,
 276}
 277
 278impl std::fmt::Debug for ExcerptInfo {
 279    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 280        f.debug_struct(type_name::<Self>())
 281            .field("id", &self.id)
 282            .field("buffer_id", &self.buffer_id)
 283            .field("path", &self.buffer.file().map(|f| f.path()))
 284            .field("range", &self.range)
 285            .finish()
 286    }
 287}
 288
 289/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 290#[derive(Debug)]
 291pub struct ExcerptBoundary {
 292    pub prev: Option<ExcerptInfo>,
 293    pub next: Option<ExcerptInfo>,
 294    /// The row in the `MultiBuffer` where the boundary is located
 295    pub row: MultiBufferRow,
 296}
 297
 298impl ExcerptBoundary {
 299    pub fn starts_new_buffer(&self) -> bool {
 300        match (self.prev.as_ref(), self.next.as_ref()) {
 301            (None, _) => true,
 302            (Some(_), None) => false,
 303            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 304        }
 305    }
 306}
 307
 308#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 309pub struct RowInfo {
 310    pub buffer_id: Option<BufferId>,
 311    pub buffer_row: Option<u32>,
 312    pub multibuffer_row: Option<MultiBufferRow>,
 313    pub diff_status: Option<diff::DiffHunkStatus>,
 314}
 315
 316/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 317#[derive(Clone)]
 318struct Excerpt {
 319    /// The unique identifier for this excerpt
 320    id: ExcerptId,
 321    /// The location of the excerpt in the [`MultiBuffer`]
 322    locator: Locator,
 323    /// The buffer being excerpted
 324    buffer_id: BufferId,
 325    /// A snapshot of the buffer being excerpted
 326    buffer: BufferSnapshot,
 327    /// The range of the buffer to be shown in the excerpt
 328    range: ExcerptRange<text::Anchor>,
 329    /// The last row in the excerpted slice of the buffer
 330    max_buffer_row: BufferRow,
 331    /// A summary of the text in the excerpt
 332    text_summary: TextSummary,
 333    has_trailing_newline: bool,
 334}
 335
 336/// A public view into an `Excerpt` in a [`MultiBuffer`].
 337///
 338/// Contains methods for getting the [`Buffer`] of the excerpt,
 339/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 340#[derive(Clone)]
 341pub struct MultiBufferExcerpt<'a> {
 342    excerpt: &'a Excerpt,
 343    diff_transforms:
 344        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 345    offset: usize,
 346    excerpt_offset: ExcerptDimension<usize>,
 347    buffer_offset: usize,
 348}
 349
 350#[derive(Clone, Debug)]
 351struct ExcerptIdMapping {
 352    id: ExcerptId,
 353    locator: Locator,
 354}
 355
 356/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 357/// These ranges are relative to the buffer itself
 358#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 359pub struct ExcerptRange<T> {
 360    /// The full range of text to be shown in the excerpt.
 361    pub context: Range<T>,
 362    /// The primary range of text to be highlighted in the excerpt.
 363    /// In a multi-buffer search, this would be the text that matched the search
 364    pub primary: Option<Range<T>>,
 365}
 366
 367#[derive(Clone, Debug, Default)]
 368pub struct ExcerptSummary {
 369    excerpt_id: ExcerptId,
 370    /// The location of the last [`Excerpt`] being summarized
 371    excerpt_locator: Locator,
 372    widest_line_number: u32,
 373    text: TextSummary,
 374}
 375
 376#[derive(Debug, Clone)]
 377pub struct DiffTransformSummary {
 378    input: TextSummary,
 379    output: TextSummary,
 380}
 381
 382#[derive(Clone)]
 383pub struct MultiBufferRows<'a> {
 384    point: Point,
 385    is_empty: bool,
 386    cursor: MultiBufferCursor<'a, Point>,
 387}
 388
 389pub struct MultiBufferChunks<'a> {
 390    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 391    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 392    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 393    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 394    buffer_chunk: Option<Chunk<'a>>,
 395    range: Range<usize>,
 396    excerpt_offset_range: Range<ExcerptOffset>,
 397    excerpt_chunks: Option<ExcerptChunks<'a>>,
 398    language_aware: bool,
 399}
 400
 401pub struct ReversedMultiBufferChunks<'a> {
 402    cursor: MultiBufferCursor<'a, usize>,
 403    current_chunks: Option<rope::Chunks<'a>>,
 404    start: usize,
 405    offset: usize,
 406}
 407
 408pub struct MultiBufferBytes<'a> {
 409    range: Range<usize>,
 410    cursor: MultiBufferCursor<'a, usize>,
 411    excerpt_bytes: Option<text::Bytes<'a>>,
 412    has_trailing_newline: bool,
 413    chunk: &'a [u8],
 414}
 415
 416pub struct ReversedMultiBufferBytes<'a> {
 417    range: Range<usize>,
 418    chunks: ReversedMultiBufferChunks<'a>,
 419    chunk: &'a [u8],
 420}
 421
 422#[derive(Clone)]
 423struct MultiBufferCursor<'a, D: TextDimension> {
 424    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 425    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 426    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 427    cached_region: Option<MultiBufferRegion<'a, D>>,
 428}
 429
 430#[derive(Clone)]
 431struct MultiBufferRegion<'a, D: TextDimension> {
 432    buffer: &'a BufferSnapshot,
 433    is_main_buffer: bool,
 434    is_inserted_hunk: bool,
 435    excerpt: &'a Excerpt,
 436    buffer_range: Range<D>,
 437    range: Range<D>,
 438    has_trailing_newline: bool,
 439}
 440
 441struct ExcerptChunks<'a> {
 442    excerpt_id: ExcerptId,
 443    content_chunks: BufferChunks<'a>,
 444    footer_height: usize,
 445}
 446
 447#[derive(Debug)]
 448struct BufferEdit {
 449    range: Range<usize>,
 450    new_text: Arc<str>,
 451    is_insertion: bool,
 452    original_indent_column: u32,
 453    excerpt_id: ExcerptId,
 454}
 455
 456#[derive(Clone, Copy, Debug, PartialEq)]
 457enum DiffChangeKind {
 458    BufferEdited,
 459    DiffUpdated { base_changed: bool },
 460    ExpandOrCollapseHunks { expand: bool },
 461}
 462
 463#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 464pub enum ExpandExcerptDirection {
 465    Up,
 466    Down,
 467    UpAndDown,
 468}
 469
 470impl ExpandExcerptDirection {
 471    pub fn should_expand_up(&self) -> bool {
 472        match self {
 473            ExpandExcerptDirection::Up => true,
 474            ExpandExcerptDirection::Down => false,
 475            ExpandExcerptDirection::UpAndDown => true,
 476        }
 477    }
 478
 479    pub fn should_expand_down(&self) -> bool {
 480        match self {
 481            ExpandExcerptDirection::Up => false,
 482            ExpandExcerptDirection::Down => true,
 483            ExpandExcerptDirection::UpAndDown => true,
 484        }
 485    }
 486}
 487
 488#[derive(Clone, Debug, PartialEq)]
 489pub struct IndentGuide {
 490    pub buffer_id: BufferId,
 491    pub start_row: MultiBufferRow,
 492    pub end_row: MultiBufferRow,
 493    pub depth: u32,
 494    pub tab_size: u32,
 495    pub settings: IndentGuideSettings,
 496}
 497
 498impl IndentGuide {
 499    pub fn indent_level(&self) -> u32 {
 500        self.depth * self.tab_size
 501    }
 502}
 503
 504impl MultiBuffer {
 505    pub fn new(capability: Capability) -> Self {
 506        Self {
 507            snapshot: RefCell::new(MultiBufferSnapshot {
 508                show_headers: true,
 509                ..MultiBufferSnapshot::default()
 510            }),
 511            buffers: RefCell::default(),
 512            diffs: HashMap::default(),
 513            all_diff_hunks_expanded: false,
 514            subscriptions: Topic::default(),
 515            singleton: false,
 516            capability,
 517            title: None,
 518            buffers_by_path: Default::default(),
 519            history: History {
 520                next_transaction_id: clock::Lamport::default(),
 521                undo_stack: Vec::new(),
 522                redo_stack: Vec::new(),
 523                transaction_depth: 0,
 524                group_interval: Duration::from_millis(300),
 525            },
 526        }
 527    }
 528
 529    pub fn without_headers(capability: Capability) -> Self {
 530        Self {
 531            snapshot: Default::default(),
 532            buffers: Default::default(),
 533            buffers_by_path: Default::default(),
 534            diffs: HashMap::default(),
 535            all_diff_hunks_expanded: false,
 536            subscriptions: Default::default(),
 537            singleton: false,
 538            capability,
 539            history: History {
 540                next_transaction_id: Default::default(),
 541                undo_stack: Default::default(),
 542                redo_stack: Default::default(),
 543                transaction_depth: 0,
 544                group_interval: Duration::from_millis(300),
 545            },
 546            title: Default::default(),
 547        }
 548    }
 549
 550    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 551        let mut buffers = HashMap::default();
 552        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 553            buffers.insert(
 554                *buffer_id,
 555                BufferState {
 556                    buffer: buffer_state.buffer.clone(),
 557                    last_version: buffer_state.last_version.clone(),
 558                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 559                    excerpts: buffer_state.excerpts.clone(),
 560                    _subscriptions: [
 561                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 562                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 563                    ],
 564                },
 565            );
 566        }
 567        let mut diff_bases = HashMap::default();
 568        for (buffer_id, diff) in self.diffs.iter() {
 569            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 570        }
 571        Self {
 572            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 573            buffers: RefCell::new(buffers),
 574            buffers_by_path: Default::default(),
 575            diffs: diff_bases,
 576            all_diff_hunks_expanded: self.all_diff_hunks_expanded,
 577            subscriptions: Default::default(),
 578            singleton: self.singleton,
 579            capability: self.capability,
 580            history: self.history.clone(),
 581            title: self.title.clone(),
 582        }
 583    }
 584
 585    pub fn with_title(mut self, title: String) -> Self {
 586        self.title = Some(title);
 587        self
 588    }
 589
 590    pub fn read_only(&self) -> bool {
 591        self.capability == Capability::ReadOnly
 592    }
 593
 594    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 595        let mut this = Self::new(buffer.read(cx).capability());
 596        this.singleton = true;
 597        this.push_excerpts(
 598            buffer,
 599            [ExcerptRange {
 600                context: text::Anchor::MIN..text::Anchor::MAX,
 601                primary: None,
 602            }],
 603            cx,
 604        );
 605        this.snapshot.borrow_mut().singleton = true;
 606        this
 607    }
 608
 609    /// Returns an up-to-date snapshot of the MultiBuffer.
 610    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 611        self.sync(cx);
 612        self.snapshot.borrow().clone()
 613    }
 614
 615    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 616        self.sync(cx);
 617        self.snapshot.borrow()
 618    }
 619
 620    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 621        if self.singleton {
 622            return Some(
 623                self.buffers
 624                    .borrow()
 625                    .values()
 626                    .next()
 627                    .unwrap()
 628                    .buffer
 629                    .clone(),
 630            );
 631        } else {
 632            None
 633        }
 634    }
 635
 636    pub fn is_singleton(&self) -> bool {
 637        self.singleton
 638    }
 639
 640    pub fn subscribe(&mut self) -> Subscription {
 641        self.subscriptions.subscribe()
 642    }
 643
 644    pub fn is_dirty(&self, cx: &App) -> bool {
 645        self.read(cx).is_dirty()
 646    }
 647
 648    pub fn has_deleted_file(&self, cx: &App) -> bool {
 649        self.read(cx).has_deleted_file()
 650    }
 651
 652    pub fn has_conflict(&self, cx: &App) -> bool {
 653        self.read(cx).has_conflict()
 654    }
 655
 656    // The `is_empty` signature doesn't match what clippy expects
 657    #[allow(clippy::len_without_is_empty)]
 658    pub fn len(&self, cx: &App) -> usize {
 659        self.read(cx).len()
 660    }
 661
 662    pub fn is_empty(&self) -> bool {
 663        self.buffers.borrow().is_empty()
 664    }
 665
 666    pub fn symbols_containing<T: ToOffset>(
 667        &self,
 668        offset: T,
 669        theme: Option<&SyntaxTheme>,
 670        cx: &App,
 671    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 672        self.read(cx).symbols_containing(offset, theme)
 673    }
 674
 675    pub fn edit<I, S, T>(
 676        &self,
 677        edits: I,
 678        autoindent_mode: Option<AutoindentMode>,
 679        cx: &mut Context<Self>,
 680    ) where
 681        I: IntoIterator<Item = (Range<S>, T)>,
 682        S: ToOffset,
 683        T: Into<Arc<str>>,
 684    {
 685        let snapshot = self.read(cx);
 686        let edits = edits
 687            .into_iter()
 688            .map(|(range, new_text)| {
 689                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 690                if range.start > range.end {
 691                    mem::swap(&mut range.start, &mut range.end);
 692                }
 693                (range, new_text.into())
 694            })
 695            .collect::<Vec<_>>();
 696
 697        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 698
 699        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 700        fn edit_internal(
 701            this: &MultiBuffer,
 702            snapshot: Ref<MultiBufferSnapshot>,
 703            edits: Vec<(Range<usize>, Arc<str>)>,
 704            mut autoindent_mode: Option<AutoindentMode>,
 705            cx: &mut Context<MultiBuffer>,
 706        ) {
 707            if this.read_only() || this.buffers.borrow().is_empty() {
 708                return;
 709            }
 710
 711            let original_indent_columns = match &mut autoindent_mode {
 712                Some(AutoindentMode::Block {
 713                    original_indent_columns,
 714                }) => mem::take(original_indent_columns),
 715                _ => Default::default(),
 716            };
 717
 718            let (buffer_edits, edited_excerpt_ids) =
 719                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 720            drop(snapshot);
 721
 722            for (buffer_id, mut edits) in buffer_edits {
 723                edits.sort_by_key(|edit| edit.range.start);
 724                this.buffers.borrow()[&buffer_id]
 725                    .buffer
 726                    .update(cx, |buffer, cx| {
 727                        let mut edits = edits.into_iter().peekable();
 728                        let mut insertions = Vec::new();
 729                        let mut original_indent_columns = Vec::new();
 730                        let mut deletions = Vec::new();
 731                        let empty_str: Arc<str> = Arc::default();
 732                        while let Some(BufferEdit {
 733                            mut range,
 734                            mut new_text,
 735                            mut is_insertion,
 736                            original_indent_column,
 737                            excerpt_id,
 738                        }) = edits.next()
 739                        {
 740                            while let Some(BufferEdit {
 741                                range: next_range,
 742                                is_insertion: next_is_insertion,
 743                                new_text: next_new_text,
 744                                excerpt_id: next_excerpt_id,
 745                                ..
 746                            }) = edits.peek()
 747                            {
 748                                if range.end >= next_range.start {
 749                                    range.end = cmp::max(next_range.end, range.end);
 750                                    is_insertion |= *next_is_insertion;
 751                                    if excerpt_id == *next_excerpt_id {
 752                                        new_text = format!("{new_text}{next_new_text}").into();
 753                                    }
 754                                    edits.next();
 755                                } else {
 756                                    break;
 757                                }
 758                            }
 759
 760                            if is_insertion {
 761                                original_indent_columns.push(original_indent_column);
 762                                insertions.push((
 763                                    buffer.anchor_before(range.start)
 764                                        ..buffer.anchor_before(range.end),
 765                                    new_text.clone(),
 766                                ));
 767                            } else if !range.is_empty() {
 768                                deletions.push((
 769                                    buffer.anchor_before(range.start)
 770                                        ..buffer.anchor_before(range.end),
 771                                    empty_str.clone(),
 772                                ));
 773                            }
 774                        }
 775
 776                        let deletion_autoindent_mode =
 777                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 778                                Some(AutoindentMode::Block {
 779                                    original_indent_columns: Default::default(),
 780                                })
 781                            } else {
 782                                autoindent_mode.clone()
 783                            };
 784                        let insertion_autoindent_mode =
 785                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 786                                Some(AutoindentMode::Block {
 787                                    original_indent_columns,
 788                                })
 789                            } else {
 790                                autoindent_mode.clone()
 791                            };
 792
 793                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 794                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 795                    })
 796            }
 797
 798            cx.emit(Event::ExcerptsEdited {
 799                ids: edited_excerpt_ids,
 800            });
 801        }
 802    }
 803
 804    fn convert_edits_to_buffer_edits(
 805        &self,
 806        edits: Vec<(Range<usize>, Arc<str>)>,
 807        snapshot: &MultiBufferSnapshot,
 808        original_indent_columns: &[u32],
 809    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 810        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 811        let mut edited_excerpt_ids = Vec::new();
 812        let mut cursor = snapshot.cursor::<usize>();
 813        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 814            let original_indent_column = original_indent_columns.get(ix).copied().unwrap_or(0);
 815
 816            cursor.seek(&range.start);
 817            let mut start_region = cursor.region().expect("start offset out of bounds");
 818            if !start_region.is_main_buffer {
 819                cursor.next();
 820                if let Some(region) = cursor.region() {
 821                    start_region = region;
 822                } else {
 823                    continue;
 824                }
 825            }
 826
 827            if range.end < start_region.range.start {
 828                continue;
 829            }
 830
 831            if range.end > start_region.range.end {
 832                cursor.seek_forward(&range.end);
 833            }
 834            let mut end_region = cursor.region().expect("end offset out of bounds");
 835            if !end_region.is_main_buffer {
 836                cursor.prev();
 837                if let Some(region) = cursor.region() {
 838                    end_region = region;
 839                } else {
 840                    continue;
 841                }
 842            }
 843
 844            if range.start > end_region.range.end {
 845                continue;
 846            }
 847
 848            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 849            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 850            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 851                .min(start_region.buffer_range.end);
 852            let buffer_end =
 853                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 854
 855            if start_region.excerpt.id == end_region.excerpt.id {
 856                if start_region.is_main_buffer {
 857                    edited_excerpt_ids.push(start_region.excerpt.id);
 858                    buffer_edits
 859                        .entry(start_region.buffer.remote_id())
 860                        .or_default()
 861                        .push(BufferEdit {
 862                            range: buffer_start..buffer_end,
 863                            new_text,
 864                            is_insertion: true,
 865                            original_indent_column,
 866                            excerpt_id: start_region.excerpt.id,
 867                        });
 868                }
 869            } else {
 870                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 871                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 872                if start_region.is_main_buffer {
 873                    edited_excerpt_ids.push(start_region.excerpt.id);
 874                    buffer_edits
 875                        .entry(start_region.buffer.remote_id())
 876                        .or_default()
 877                        .push(BufferEdit {
 878                            range: start_excerpt_range,
 879                            new_text: new_text.clone(),
 880                            is_insertion: true,
 881                            original_indent_column,
 882                            excerpt_id: start_region.excerpt.id,
 883                        });
 884                }
 885                if end_region.is_main_buffer {
 886                    edited_excerpt_ids.push(end_region.excerpt.id);
 887                    buffer_edits
 888                        .entry(end_region.buffer.remote_id())
 889                        .or_default()
 890                        .push(BufferEdit {
 891                            range: end_excerpt_range,
 892                            new_text: new_text.clone(),
 893                            is_insertion: false,
 894                            original_indent_column,
 895                            excerpt_id: end_region.excerpt.id,
 896                        });
 897                }
 898
 899                cursor.seek(&range.start);
 900                cursor.next_excerpt();
 901                while let Some(region) = cursor.region() {
 902                    if region.excerpt.id == end_region.excerpt.id {
 903                        break;
 904                    }
 905                    if region.is_main_buffer {
 906                        edited_excerpt_ids.push(region.excerpt.id);
 907                        buffer_edits
 908                            .entry(region.buffer.remote_id())
 909                            .or_default()
 910                            .push(BufferEdit {
 911                                range: region.buffer_range,
 912                                new_text: new_text.clone(),
 913                                is_insertion: false,
 914                                original_indent_column,
 915                                excerpt_id: region.excerpt.id,
 916                            });
 917                    }
 918                    cursor.next_excerpt();
 919                }
 920            }
 921        }
 922        (buffer_edits, edited_excerpt_ids)
 923    }
 924
 925    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 926    where
 927        I: IntoIterator<Item = Range<S>>,
 928        S: ToOffset,
 929    {
 930        let snapshot = self.read(cx);
 931        let empty = Arc::<str>::from("");
 932        let edits = ranges
 933            .into_iter()
 934            .map(|range| {
 935                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 936                if range.start > range.end {
 937                    mem::swap(&mut range.start, &mut range.end);
 938                }
 939                (range, empty.clone())
 940            })
 941            .collect::<Vec<_>>();
 942
 943        return autoindent_ranges_internal(self, snapshot, edits, cx);
 944
 945        fn autoindent_ranges_internal(
 946            this: &MultiBuffer,
 947            snapshot: Ref<MultiBufferSnapshot>,
 948            edits: Vec<(Range<usize>, Arc<str>)>,
 949            cx: &mut Context<MultiBuffer>,
 950        ) {
 951            if this.read_only() || this.buffers.borrow().is_empty() {
 952                return;
 953            }
 954
 955            let (buffer_edits, edited_excerpt_ids) =
 956                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
 957            drop(snapshot);
 958
 959            for (buffer_id, mut edits) in buffer_edits {
 960                edits.sort_unstable_by_key(|edit| edit.range.start);
 961
 962                let mut ranges: Vec<Range<usize>> = Vec::new();
 963                for edit in edits {
 964                    if let Some(last_range) = ranges.last_mut() {
 965                        if edit.range.start <= last_range.end {
 966                            last_range.end = last_range.end.max(edit.range.end);
 967                            continue;
 968                        }
 969                    }
 970                    ranges.push(edit.range);
 971                }
 972
 973                this.buffers.borrow()[&buffer_id]
 974                    .buffer
 975                    .update(cx, |buffer, cx| {
 976                        buffer.autoindent_ranges(ranges, cx);
 977                    })
 978            }
 979
 980            cx.emit(Event::ExcerptsEdited {
 981                ids: edited_excerpt_ids,
 982            });
 983        }
 984    }
 985
 986    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
 987    // You can also request the insertion of empty lines above and below the line starting at the returned point.
 988    // Panics if the given position is invalid.
 989    pub fn insert_empty_line(
 990        &mut self,
 991        position: impl ToPoint,
 992        space_above: bool,
 993        space_below: bool,
 994        cx: &mut Context<Self>,
 995    ) -> Point {
 996        let multibuffer_point = position.to_point(&self.read(cx));
 997        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
 998        self.start_transaction(cx);
 999        let empty_line_start = buffer.update(cx, |buffer, cx| {
1000            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1001        });
1002        self.end_transaction(cx);
1003        multibuffer_point + (empty_line_start - buffer_point)
1004    }
1005
1006    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1007        self.start_transaction_at(Instant::now(), cx)
1008    }
1009
1010    pub fn start_transaction_at(
1011        &mut self,
1012        now: Instant,
1013        cx: &mut Context<Self>,
1014    ) -> Option<TransactionId> {
1015        if let Some(buffer) = self.as_singleton() {
1016            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1017        }
1018
1019        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1020            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1021        }
1022        self.history.start_transaction(now)
1023    }
1024
1025    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1026        self.end_transaction_at(Instant::now(), cx)
1027    }
1028
1029    pub fn end_transaction_at(
1030        &mut self,
1031        now: Instant,
1032        cx: &mut Context<Self>,
1033    ) -> Option<TransactionId> {
1034        if let Some(buffer) = self.as_singleton() {
1035            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1036        }
1037
1038        let mut buffer_transactions = HashMap::default();
1039        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1040            if let Some(transaction_id) =
1041                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1042            {
1043                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1044            }
1045        }
1046
1047        if self.history.end_transaction(now, buffer_transactions) {
1048            let transaction_id = self.history.group().unwrap();
1049            Some(transaction_id)
1050        } else {
1051            None
1052        }
1053    }
1054
1055    pub fn edited_ranges_for_transaction<D>(
1056        &self,
1057        transaction_id: TransactionId,
1058        cx: &App,
1059    ) -> Vec<Range<D>>
1060    where
1061        D: TextDimension + Ord + Sub<D, Output = D>,
1062    {
1063        let Some(transaction) = self.history.transaction(transaction_id) else {
1064            return Vec::new();
1065        };
1066
1067        let mut ranges = Vec::new();
1068        let snapshot = self.read(cx);
1069        let buffers = self.buffers.borrow();
1070        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1071
1072        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1073            let Some(buffer_state) = buffers.get(buffer_id) else {
1074                continue;
1075            };
1076
1077            let buffer = buffer_state.buffer.read(cx);
1078            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1079                for excerpt_id in &buffer_state.excerpts {
1080                    cursor.seek(excerpt_id, Bias::Left, &());
1081                    if let Some(excerpt) = cursor.item() {
1082                        if excerpt.locator == *excerpt_id {
1083                            let excerpt_buffer_start =
1084                                excerpt.range.context.start.summary::<D>(buffer);
1085                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1086                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1087                            if excerpt_range.contains(&range.start)
1088                                && excerpt_range.contains(&range.end)
1089                            {
1090                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1091
1092                                let mut start = excerpt_start;
1093                                start.add_assign(&(range.start - excerpt_buffer_start));
1094                                let mut end = excerpt_start;
1095                                end.add_assign(&(range.end - excerpt_buffer_start));
1096
1097                                ranges.push(start..end);
1098                                break;
1099                            }
1100                        }
1101                    }
1102                }
1103            }
1104        }
1105
1106        ranges.sort_by_key(|range| range.start);
1107        ranges
1108    }
1109
1110    pub fn merge_transactions(
1111        &mut self,
1112        transaction: TransactionId,
1113        destination: TransactionId,
1114        cx: &mut Context<Self>,
1115    ) {
1116        if let Some(buffer) = self.as_singleton() {
1117            buffer.update(cx, |buffer, _| {
1118                buffer.merge_transactions(transaction, destination)
1119            });
1120        } else if let Some(transaction) = self.history.forget(transaction) {
1121            if let Some(destination) = self.history.transaction_mut(destination) {
1122                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1123                    if let Some(destination_buffer_transaction_id) =
1124                        destination.buffer_transactions.get(&buffer_id)
1125                    {
1126                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1127                            state.buffer.update(cx, |buffer, _| {
1128                                buffer.merge_transactions(
1129                                    buffer_transaction_id,
1130                                    *destination_buffer_transaction_id,
1131                                )
1132                            });
1133                        }
1134                    } else {
1135                        destination
1136                            .buffer_transactions
1137                            .insert(buffer_id, buffer_transaction_id);
1138                    }
1139                }
1140            }
1141        }
1142    }
1143
1144    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1145        self.history.finalize_last_transaction();
1146        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1147            buffer.update(cx, |buffer, _| {
1148                buffer.finalize_last_transaction();
1149            });
1150        }
1151    }
1152
1153    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1154    where
1155        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1156    {
1157        self.history
1158            .push_transaction(buffer_transactions, Instant::now(), cx);
1159        self.history.finalize_last_transaction();
1160    }
1161
1162    pub fn group_until_transaction(
1163        &mut self,
1164        transaction_id: TransactionId,
1165        cx: &mut Context<Self>,
1166    ) {
1167        if let Some(buffer) = self.as_singleton() {
1168            buffer.update(cx, |buffer, _| {
1169                buffer.group_until_transaction(transaction_id)
1170            });
1171        } else {
1172            self.history.group_until(transaction_id);
1173        }
1174    }
1175
1176    pub fn set_active_selections(
1177        &self,
1178        selections: &[Selection<Anchor>],
1179        line_mode: bool,
1180        cursor_shape: CursorShape,
1181        cx: &mut Context<Self>,
1182    ) {
1183        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1184            Default::default();
1185        let snapshot = self.read(cx);
1186        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1187        for selection in selections {
1188            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1189            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1190
1191            cursor.seek(&Some(start_locator), Bias::Left, &());
1192            while let Some(excerpt) = cursor.item() {
1193                if excerpt.locator > *end_locator {
1194                    break;
1195                }
1196
1197                let mut start = excerpt.range.context.start;
1198                let mut end = excerpt.range.context.end;
1199                if excerpt.id == selection.start.excerpt_id {
1200                    start = selection.start.text_anchor;
1201                }
1202                if excerpt.id == selection.end.excerpt_id {
1203                    end = selection.end.text_anchor;
1204                }
1205                selections_by_buffer
1206                    .entry(excerpt.buffer_id)
1207                    .or_default()
1208                    .push(Selection {
1209                        id: selection.id,
1210                        start,
1211                        end,
1212                        reversed: selection.reversed,
1213                        goal: selection.goal,
1214                    });
1215
1216                cursor.next(&());
1217            }
1218        }
1219
1220        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1221            if !selections_by_buffer.contains_key(buffer_id) {
1222                buffer_state
1223                    .buffer
1224                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1225            }
1226        }
1227
1228        for (buffer_id, mut selections) in selections_by_buffer {
1229            self.buffers.borrow()[&buffer_id]
1230                .buffer
1231                .update(cx, |buffer, cx| {
1232                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1233                    let mut selections = selections.into_iter().peekable();
1234                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1235                        let mut selection = selections.next()?;
1236                        while let Some(next_selection) = selections.peek() {
1237                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1238                                let next_selection = selections.next().unwrap();
1239                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1240                                    selection.end = next_selection.end;
1241                                }
1242                            } else {
1243                                break;
1244                            }
1245                        }
1246                        Some(selection)
1247                    }));
1248                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1249                });
1250        }
1251    }
1252
1253    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1254        for buffer in self.buffers.borrow().values() {
1255            buffer
1256                .buffer
1257                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1258        }
1259    }
1260
1261    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1262        let mut transaction_id = None;
1263        if let Some(buffer) = self.as_singleton() {
1264            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1265        } else {
1266            while let Some(transaction) = self.history.pop_undo() {
1267                let mut undone = false;
1268                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1269                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1270                        undone |= buffer.update(cx, |buffer, cx| {
1271                            let undo_to = *buffer_transaction_id;
1272                            if let Some(entry) = buffer.peek_undo_stack() {
1273                                *buffer_transaction_id = entry.transaction_id();
1274                            }
1275                            buffer.undo_to_transaction(undo_to, cx)
1276                        });
1277                    }
1278                }
1279
1280                if undone {
1281                    transaction_id = Some(transaction.id);
1282                    break;
1283                }
1284            }
1285        }
1286
1287        if let Some(transaction_id) = transaction_id {
1288            cx.emit(Event::TransactionUndone { transaction_id });
1289        }
1290
1291        transaction_id
1292    }
1293
1294    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1295        if let Some(buffer) = self.as_singleton() {
1296            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1297        }
1298
1299        while let Some(transaction) = self.history.pop_redo() {
1300            let mut redone = false;
1301            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1302                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1303                    redone |= buffer.update(cx, |buffer, cx| {
1304                        let redo_to = *buffer_transaction_id;
1305                        if let Some(entry) = buffer.peek_redo_stack() {
1306                            *buffer_transaction_id = entry.transaction_id();
1307                        }
1308                        buffer.redo_to_transaction(redo_to, cx)
1309                    });
1310                }
1311            }
1312
1313            if redone {
1314                return Some(transaction.id);
1315            }
1316        }
1317
1318        None
1319    }
1320
1321    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1322        if let Some(buffer) = self.as_singleton() {
1323            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1324        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1325            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1326                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1327                    buffer.update(cx, |buffer, cx| {
1328                        buffer.undo_transaction(*transaction_id, cx)
1329                    });
1330                }
1331            }
1332        }
1333    }
1334
1335    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1336        if let Some(buffer) = self.as_singleton() {
1337            buffer.update(cx, |buffer, _| {
1338                buffer.forget_transaction(transaction_id);
1339            });
1340        } else if let Some(transaction) = self.history.forget(transaction_id) {
1341            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1342                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1343                    state.buffer.update(cx, |buffer, _| {
1344                        buffer.forget_transaction(buffer_transaction_id);
1345                    });
1346                }
1347            }
1348        }
1349    }
1350
1351    pub fn push_excerpts<O>(
1352        &mut self,
1353        buffer: Entity<Buffer>,
1354        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1355        cx: &mut Context<Self>,
1356    ) -> Vec<ExcerptId>
1357    where
1358        O: text::ToOffset,
1359    {
1360        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1361    }
1362
1363    pub fn push_excerpts_with_context_lines<O>(
1364        &mut self,
1365        buffer: Entity<Buffer>,
1366        ranges: Vec<Range<O>>,
1367        context_line_count: u32,
1368        cx: &mut Context<Self>,
1369    ) -> Vec<Range<Anchor>>
1370    where
1371        O: text::ToPoint + text::ToOffset,
1372    {
1373        let buffer_id = buffer.read(cx).remote_id();
1374        let buffer_snapshot = buffer.read(cx).snapshot();
1375        let (excerpt_ranges, range_counts) =
1376            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1377
1378        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1379
1380        let mut anchor_ranges = Vec::new();
1381        let mut ranges = ranges.into_iter();
1382        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1383            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1384                let start = Anchor {
1385                    buffer_id: Some(buffer_id),
1386                    excerpt_id,
1387                    text_anchor: buffer_snapshot.anchor_after(range.start),
1388                    diff_base_anchor: None,
1389                };
1390                let end = Anchor {
1391                    buffer_id: Some(buffer_id),
1392                    excerpt_id,
1393                    text_anchor: buffer_snapshot.anchor_after(range.end),
1394                    diff_base_anchor: None,
1395                };
1396                start..end
1397            }))
1398        }
1399        anchor_ranges
1400    }
1401
1402    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1403        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1404        let snapshot = self.snapshot(cx);
1405        let excerpt = snapshot.excerpt(*excerpt_id)?;
1406        Some(Anchor::in_buffer(
1407            *excerpt_id,
1408            excerpt.buffer_id,
1409            excerpt.range.context.start,
1410        ))
1411    }
1412
1413    pub fn set_excerpts_for_path(
1414        &mut self,
1415        path: PathKey,
1416        buffer: Entity<Buffer>,
1417        ranges: Vec<Range<Point>>,
1418        context_line_count: u32,
1419        cx: &mut Context<Self>,
1420    ) {
1421        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1422
1423        let mut insert_after = self
1424            .buffers_by_path
1425            .range(..path.clone())
1426            .next_back()
1427            .map(|(_, value)| *value.last().unwrap())
1428            .unwrap_or(ExcerptId::min());
1429        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1430
1431        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1432
1433        let mut new_iter = new.into_iter().peekable();
1434        let mut existing_iter = existing.into_iter().peekable();
1435
1436        let mut new_excerpt_ids = Vec::new();
1437        let mut to_remove = Vec::new();
1438        let mut to_insert = Vec::new();
1439        let snapshot = self.snapshot(cx);
1440
1441        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1442        excerpts_cursor.next(&());
1443
1444        loop {
1445            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1446                (Some(new), Some(existing)) => (new, existing),
1447                (None, None) => break,
1448                (None, Some(_)) => {
1449                    to_remove.push(existing_iter.next().unwrap());
1450                    continue;
1451                }
1452                (Some(_), None) => {
1453                    to_insert.push(new_iter.next().unwrap());
1454                    continue;
1455                }
1456            };
1457            let locator = snapshot.excerpt_locator_for_id(*existing);
1458            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1459            let existing_excerpt = excerpts_cursor.item().unwrap();
1460            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1461                to_remove.push(existing_iter.next().unwrap());
1462                to_insert.push(new_iter.next().unwrap());
1463                continue;
1464            }
1465
1466            let existing_start = existing_excerpt
1467                .range
1468                .context
1469                .start
1470                .to_point(&buffer_snapshot);
1471            let existing_end = existing_excerpt
1472                .range
1473                .context
1474                .end
1475                .to_point(&buffer_snapshot);
1476
1477            if existing_end < new.context.start {
1478                to_remove.push(existing_iter.next().unwrap());
1479                continue;
1480            } else if existing_start > new.context.end {
1481                to_insert.push(new_iter.next().unwrap());
1482                continue;
1483            }
1484
1485            // maybe merge overlapping excerpts?
1486            // it's hard to distinguish between a manually expanded excerpt, and one that
1487            // got smaller because of a missing diff.
1488            if existing_start == new.context.start && existing_end == new.context.end {
1489                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1490                    insert_after,
1491                    buffer.clone(),
1492                    mem::take(&mut to_insert),
1493                    cx,
1494                ));
1495                insert_after = existing_iter.next().unwrap();
1496                new_excerpt_ids.push(insert_after);
1497                new_iter.next();
1498            } else {
1499                to_remove.push(existing_iter.next().unwrap());
1500                to_insert.push(new_iter.next().unwrap());
1501            }
1502        }
1503
1504        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1505            insert_after,
1506            buffer,
1507            to_insert,
1508            cx,
1509        ));
1510        self.remove_excerpts(to_remove, cx);
1511        if new_excerpt_ids.is_empty() {
1512            self.buffers_by_path.remove(&path);
1513        } else {
1514            self.buffers_by_path.insert(path, new_excerpt_ids);
1515        }
1516    }
1517
1518    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1519        self.buffers_by_path.keys().cloned()
1520    }
1521
1522    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1523        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1524            self.remove_excerpts(to_remove, cx)
1525        }
1526    }
1527
1528    pub fn push_multiple_excerpts_with_context_lines(
1529        &self,
1530        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1531        context_line_count: u32,
1532        cx: &mut Context<Self>,
1533    ) -> Task<Vec<Range<Anchor>>> {
1534        use futures::StreamExt;
1535
1536        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1537
1538        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1539
1540        for (buffer, ranges) in buffers_with_ranges {
1541            let (buffer_id, buffer_snapshot) =
1542                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1543
1544            buffer_ids.push(buffer_id);
1545
1546            cx.background_executor()
1547                .spawn({
1548                    let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1549
1550                    async move {
1551                        let (excerpt_ranges, counts) =
1552                            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1553                        excerpt_ranges_tx
1554                            .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1555                            .await
1556                            .ok();
1557                    }
1558                })
1559                .detach()
1560        }
1561
1562        cx.spawn(move |this, mut cx| async move {
1563            let mut results_by_buffer_id = HashMap::default();
1564            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1565                excerpt_ranges_rx.next().await
1566            {
1567                results_by_buffer_id
1568                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1569            }
1570
1571            let mut multi_buffer_ranges = Vec::default();
1572            'outer: for buffer_id in buffer_ids {
1573                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1574                    results_by_buffer_id.remove(&buffer_id)
1575                else {
1576                    continue;
1577                };
1578
1579                let mut ranges = ranges.into_iter();
1580                let mut range_counts = range_counts.into_iter();
1581                for excerpt_ranges in excerpt_ranges.chunks(100) {
1582                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1583                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1584                    }) {
1585                        Ok(excerpt_ids) => excerpt_ids,
1586                        Err(_) => continue 'outer,
1587                    };
1588
1589                    for (excerpt_id, range_count) in
1590                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1591                    {
1592                        for range in ranges.by_ref().take(range_count) {
1593                            let start = Anchor {
1594                                buffer_id: Some(buffer_id),
1595                                excerpt_id,
1596                                text_anchor: range.start,
1597                                diff_base_anchor: None,
1598                            };
1599                            let end = Anchor {
1600                                buffer_id: Some(buffer_id),
1601                                excerpt_id,
1602                                text_anchor: range.end,
1603                                diff_base_anchor: None,
1604                            };
1605                            multi_buffer_ranges.push(start..end);
1606                        }
1607                    }
1608                }
1609            }
1610
1611            multi_buffer_ranges
1612        })
1613    }
1614
1615    pub fn insert_excerpts_after<O>(
1616        &mut self,
1617        prev_excerpt_id: ExcerptId,
1618        buffer: Entity<Buffer>,
1619        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1620        cx: &mut Context<Self>,
1621    ) -> Vec<ExcerptId>
1622    where
1623        O: text::ToOffset,
1624    {
1625        let mut ids = Vec::new();
1626        let mut next_excerpt_id =
1627            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1628                last_entry.id.0 + 1
1629            } else {
1630                1
1631            };
1632        self.insert_excerpts_with_ids_after(
1633            prev_excerpt_id,
1634            buffer,
1635            ranges.into_iter().map(|range| {
1636                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1637                ids.push(id);
1638                (id, range)
1639            }),
1640            cx,
1641        );
1642        ids
1643    }
1644
1645    pub fn insert_excerpts_with_ids_after<O>(
1646        &mut self,
1647        prev_excerpt_id: ExcerptId,
1648        buffer: Entity<Buffer>,
1649        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1650        cx: &mut Context<Self>,
1651    ) where
1652        O: text::ToOffset,
1653    {
1654        assert_eq!(self.history.transaction_depth, 0);
1655        let mut ranges = ranges.into_iter().peekable();
1656        if ranges.peek().is_none() {
1657            return Default::default();
1658        }
1659
1660        self.sync(cx);
1661
1662        let buffer_id = buffer.read(cx).remote_id();
1663        let buffer_snapshot = buffer.read(cx).snapshot();
1664
1665        let mut buffers = self.buffers.borrow_mut();
1666        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1667            last_version: buffer_snapshot.version().clone(),
1668            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1669            excerpts: Default::default(),
1670            _subscriptions: [
1671                cx.observe(&buffer, |_, _, cx| cx.notify()),
1672                cx.subscribe(&buffer, Self::on_buffer_event),
1673            ],
1674            buffer: buffer.clone(),
1675        });
1676
1677        let mut snapshot = self.snapshot.borrow_mut();
1678
1679        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1680        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1681        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1682        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1683        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1684
1685        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1686        new_excerpts.update_last(
1687            |excerpt| {
1688                excerpt.has_trailing_newline = true;
1689            },
1690            &(),
1691        );
1692
1693        let next_locator = if let Some(excerpt) = cursor.item() {
1694            excerpt.locator.clone()
1695        } else {
1696            Locator::max()
1697        };
1698
1699        let mut excerpts = Vec::new();
1700        while let Some((id, range)) = ranges.next() {
1701            let locator = Locator::between(&prev_locator, &next_locator);
1702            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1703                buffer_state.excerpts.insert(ix, locator.clone());
1704            }
1705            let range = ExcerptRange {
1706                context: buffer_snapshot.anchor_before(&range.context.start)
1707                    ..buffer_snapshot.anchor_after(&range.context.end),
1708                primary: range.primary.map(|primary| {
1709                    buffer_snapshot.anchor_before(&primary.start)
1710                        ..buffer_snapshot.anchor_after(&primary.end)
1711                }),
1712            };
1713            excerpts.push((id, range.clone()));
1714            let excerpt = Excerpt::new(
1715                id,
1716                locator.clone(),
1717                buffer_id,
1718                buffer_snapshot.clone(),
1719                range,
1720                ranges.peek().is_some() || cursor.item().is_some(),
1721            );
1722            new_excerpts.push(excerpt, &());
1723            prev_locator = locator.clone();
1724
1725            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1726                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1727            }
1728            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1729        }
1730
1731        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1732
1733        let suffix = cursor.suffix(&());
1734        let changed_trailing_excerpt = suffix.is_empty();
1735        new_excerpts.append(suffix, &());
1736        drop(cursor);
1737        snapshot.excerpts = new_excerpts;
1738        snapshot.excerpt_ids = new_excerpt_ids;
1739        if changed_trailing_excerpt {
1740            snapshot.trailing_excerpt_update_count += 1;
1741        }
1742
1743        self.sync_diff_transforms(
1744            &mut snapshot,
1745            vec![Edit {
1746                old: edit_start..edit_start,
1747                new: edit_start..edit_end,
1748            }],
1749            DiffChangeKind::BufferEdited,
1750        );
1751        cx.emit(Event::Edited {
1752            singleton_buffer_edited: false,
1753            edited_buffer: None,
1754        });
1755        cx.emit(Event::ExcerptsAdded {
1756            buffer,
1757            predecessor: prev_excerpt_id,
1758            excerpts,
1759        });
1760        cx.notify();
1761    }
1762
1763    pub fn clear(&mut self, cx: &mut Context<Self>) {
1764        self.sync(cx);
1765        let ids = self.excerpt_ids();
1766        self.buffers.borrow_mut().clear();
1767        let mut snapshot = self.snapshot.borrow_mut();
1768        let start = ExcerptOffset::new(0);
1769        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1770        snapshot.excerpts = Default::default();
1771        snapshot.trailing_excerpt_update_count += 1;
1772        snapshot.is_dirty = false;
1773        snapshot.has_deleted_file = false;
1774        snapshot.has_conflict = false;
1775
1776        self.sync_diff_transforms(
1777            &mut snapshot,
1778            vec![Edit {
1779                old: start..prev_len,
1780                new: start..start,
1781            }],
1782            DiffChangeKind::BufferEdited,
1783        );
1784        cx.emit(Event::Edited {
1785            singleton_buffer_edited: false,
1786            edited_buffer: None,
1787        });
1788        cx.emit(Event::ExcerptsRemoved { ids });
1789        cx.notify();
1790    }
1791
1792    pub fn excerpts_for_buffer(
1793        &self,
1794        buffer_id: BufferId,
1795        cx: &App,
1796    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1797        let mut excerpts = Vec::new();
1798        let snapshot = self.read(cx);
1799        let buffers = self.buffers.borrow();
1800        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1801        for locator in buffers
1802            .get(&buffer_id)
1803            .map(|state| &state.excerpts)
1804            .into_iter()
1805            .flatten()
1806        {
1807            cursor.seek_forward(&Some(locator), Bias::Left, &());
1808            if let Some(excerpt) = cursor.item() {
1809                if excerpt.locator == *locator {
1810                    excerpts.push((excerpt.id, excerpt.range.clone()));
1811                }
1812            }
1813        }
1814
1815        excerpts
1816    }
1817
1818    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1819        let snapshot = self.read(cx);
1820        let buffers = self.buffers.borrow();
1821        let mut excerpts = snapshot
1822            .excerpts
1823            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1824        let mut diff_transforms = snapshot
1825            .diff_transforms
1826            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1827        diff_transforms.next(&());
1828        let locators = buffers
1829            .get(&buffer_id)
1830            .into_iter()
1831            .flat_map(|state| &state.excerpts);
1832        let mut result = Vec::new();
1833        for locator in locators {
1834            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1835            if let Some(excerpt) = excerpts.item() {
1836                if excerpt.locator == *locator {
1837                    let excerpt_start = excerpts.start().1.clone();
1838                    let excerpt_end =
1839                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1840
1841                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1842                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1843                    let start = diff_transforms.start().1 .0 + overshoot;
1844
1845                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1846                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1847                    let end = diff_transforms.start().1 .0 + overshoot;
1848
1849                    result.push(start..end)
1850                }
1851            }
1852        }
1853        result
1854    }
1855
1856    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1857        self.snapshot
1858            .borrow()
1859            .excerpts
1860            .iter()
1861            .map(|entry| entry.buffer_id)
1862            .collect()
1863    }
1864
1865    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1866        self.snapshot
1867            .borrow()
1868            .excerpts
1869            .iter()
1870            .map(|entry| entry.id)
1871            .collect()
1872    }
1873
1874    pub fn excerpt_containing(
1875        &self,
1876        position: impl ToOffset,
1877        cx: &App,
1878    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1879        let snapshot = self.read(cx);
1880        let offset = position.to_offset(&snapshot);
1881
1882        let mut cursor = snapshot.cursor::<usize>();
1883        cursor.seek(&offset);
1884        cursor
1885            .excerpt()
1886            .or_else(|| snapshot.excerpts.last())
1887            .map(|excerpt| {
1888                (
1889                    excerpt.id,
1890                    self.buffers
1891                        .borrow()
1892                        .get(&excerpt.buffer_id)
1893                        .unwrap()
1894                        .buffer
1895                        .clone(),
1896                    excerpt.range.context.clone(),
1897                )
1898            })
1899    }
1900
1901    // If point is at the end of the buffer, the last excerpt is returned
1902    pub fn point_to_buffer_offset<T: ToOffset>(
1903        &self,
1904        point: T,
1905        cx: &App,
1906    ) -> Option<(Entity<Buffer>, usize)> {
1907        let snapshot = self.read(cx);
1908        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1909        Some((
1910            self.buffers
1911                .borrow()
1912                .get(&buffer.remote_id())?
1913                .buffer
1914                .clone(),
1915            offset,
1916        ))
1917    }
1918
1919    // If point is at the end of the buffer, the last excerpt is returned
1920    pub fn point_to_buffer_point<T: ToPoint>(
1921        &self,
1922        point: T,
1923        cx: &App,
1924    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1925        let snapshot = self.read(cx);
1926        let point = point.to_point(&snapshot);
1927        let mut cursor = snapshot.cursor::<Point>();
1928        cursor.seek(&point);
1929
1930        cursor.region().and_then(|region| {
1931            if !region.is_main_buffer {
1932                return None;
1933            }
1934
1935            let overshoot = point - region.range.start;
1936            let buffer_point = region.buffer_range.start + overshoot;
1937            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
1938                .buffer
1939                .clone();
1940            Some((buffer, buffer_point, region.excerpt.id))
1941        })
1942    }
1943
1944    pub fn buffer_point_to_anchor(
1945        &self,
1946        buffer: &Entity<Buffer>,
1947        point: Point,
1948        cx: &App,
1949    ) -> Option<Anchor> {
1950        let mut found = None;
1951        let snapshot = buffer.read(cx).snapshot();
1952        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1953            let start = range.context.start.to_point(&snapshot);
1954            let end = range.context.end.to_point(&snapshot);
1955            if start <= point && point < end {
1956                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1957                break;
1958            }
1959            if point < start {
1960                found = Some((start, excerpt_id));
1961            }
1962            if point > end {
1963                found = Some((end, excerpt_id));
1964            }
1965        }
1966
1967        found.map(|(point, excerpt_id)| {
1968            let text_anchor = snapshot.anchor_after(point);
1969            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1970        })
1971    }
1972
1973    pub fn remove_excerpts(
1974        &mut self,
1975        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1976        cx: &mut Context<Self>,
1977    ) {
1978        self.sync(cx);
1979        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1980        if ids.is_empty() {
1981            return;
1982        }
1983
1984        let mut buffers = self.buffers.borrow_mut();
1985        let mut snapshot = self.snapshot.borrow_mut();
1986        let mut new_excerpts = SumTree::default();
1987        let mut cursor = snapshot
1988            .excerpts
1989            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
1990        let mut edits = Vec::new();
1991        let mut excerpt_ids = ids.iter().copied().peekable();
1992
1993        while let Some(excerpt_id) = excerpt_ids.next() {
1994            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1995            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1996            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1997
1998            if let Some(mut excerpt) = cursor.item() {
1999                if excerpt.id != excerpt_id {
2000                    continue;
2001                }
2002                let mut old_start = cursor.start().1;
2003
2004                // Skip over the removed excerpt.
2005                'remove_excerpts: loop {
2006                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2007                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2008                        if buffer_state.excerpts.is_empty() {
2009                            buffers.remove(&excerpt.buffer_id);
2010                        }
2011                    }
2012                    cursor.next(&());
2013
2014                    // Skip over any subsequent excerpts that are also removed.
2015                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2016                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2017                        if let Some(next_excerpt) = cursor.item() {
2018                            if next_excerpt.locator == *next_locator {
2019                                excerpt_ids.next();
2020                                excerpt = next_excerpt;
2021                                continue 'remove_excerpts;
2022                            }
2023                        }
2024                    }
2025
2026                    break;
2027                }
2028
2029                // When removing the last excerpt, remove the trailing newline from
2030                // the previous excerpt.
2031                if cursor.item().is_none() && old_start.value > 0 {
2032                    old_start.value -= 1;
2033                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2034                }
2035
2036                // Push an edit for the removal of this run of excerpts.
2037                let old_end = cursor.start().1;
2038                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2039                edits.push(Edit {
2040                    old: old_start..old_end,
2041                    new: new_start..new_start,
2042                });
2043            }
2044        }
2045        let suffix = cursor.suffix(&());
2046        let changed_trailing_excerpt = suffix.is_empty();
2047        new_excerpts.append(suffix, &());
2048        drop(cursor);
2049        snapshot.excerpts = new_excerpts;
2050
2051        if changed_trailing_excerpt {
2052            snapshot.trailing_excerpt_update_count += 1;
2053        }
2054
2055        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2056        cx.emit(Event::Edited {
2057            singleton_buffer_edited: false,
2058            edited_buffer: None,
2059        });
2060        cx.emit(Event::ExcerptsRemoved { ids });
2061        cx.notify();
2062    }
2063
2064    pub fn wait_for_anchors<'a>(
2065        &self,
2066        anchors: impl 'a + Iterator<Item = Anchor>,
2067        cx: &mut Context<Self>,
2068    ) -> impl 'static + Future<Output = Result<()>> {
2069        let borrow = self.buffers.borrow();
2070        let mut error = None;
2071        let mut futures = Vec::new();
2072        for anchor in anchors {
2073            if let Some(buffer_id) = anchor.buffer_id {
2074                if let Some(buffer) = borrow.get(&buffer_id) {
2075                    buffer.buffer.update(cx, |buffer, _| {
2076                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2077                    });
2078                } else {
2079                    error = Some(anyhow!(
2080                        "buffer {buffer_id} is not part of this multi-buffer"
2081                    ));
2082                    break;
2083                }
2084            }
2085        }
2086        async move {
2087            if let Some(error) = error {
2088                Err(error)?;
2089            }
2090            for future in futures {
2091                future.await?;
2092            }
2093            Ok(())
2094        }
2095    }
2096
2097    pub fn text_anchor_for_position<T: ToOffset>(
2098        &self,
2099        position: T,
2100        cx: &App,
2101    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2102        let snapshot = self.read(cx);
2103        let anchor = snapshot.anchor_before(position);
2104        let buffer = self
2105            .buffers
2106            .borrow()
2107            .get(&anchor.buffer_id?)?
2108            .buffer
2109            .clone();
2110        Some((buffer, anchor.text_anchor))
2111    }
2112
2113    fn on_buffer_event(
2114        &mut self,
2115        buffer: Entity<Buffer>,
2116        event: &language::BufferEvent,
2117        cx: &mut Context<Self>,
2118    ) {
2119        cx.emit(match event {
2120            language::BufferEvent::Edited => Event::Edited {
2121                singleton_buffer_edited: true,
2122                edited_buffer: Some(buffer.clone()),
2123            },
2124            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2125            language::BufferEvent::Saved => Event::Saved,
2126            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2127            language::BufferEvent::Reloaded => Event::Reloaded,
2128            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2129            language::BufferEvent::LanguageChanged => {
2130                Event::LanguageChanged(buffer.read(cx).remote_id())
2131            }
2132            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2133            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2134            language::BufferEvent::Closed => Event::Closed,
2135            language::BufferEvent::Discarded => Event::Discarded,
2136            language::BufferEvent::CapabilityChanged => {
2137                self.capability = buffer.read(cx).capability();
2138                Event::CapabilityChanged
2139            }
2140            language::BufferEvent::Operation { .. } => return,
2141        });
2142    }
2143
2144    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2145        self.sync(cx);
2146        let mut snapshot = self.snapshot.borrow_mut();
2147        let diff = diff.read(cx);
2148        let buffer_id = diff.buffer_id;
2149        let diff = diff.snapshot.clone();
2150        snapshot.diffs.insert(buffer_id, diff);
2151    }
2152
2153    fn buffer_diff_changed(
2154        &mut self,
2155        diff: Entity<BufferDiff>,
2156        range: Range<text::Anchor>,
2157        cx: &mut Context<Self>,
2158    ) {
2159        self.sync(cx);
2160
2161        let diff = diff.read(cx);
2162        let buffer_id = diff.buffer_id;
2163        let mut diff = diff.snapshot.clone();
2164        if diff.base_text.is_none() && self.all_diff_hunks_expanded {
2165            diff = BufferDiffSnapshot::new_with_single_insertion(cx);
2166        }
2167
2168        let mut snapshot = self.snapshot.borrow_mut();
2169        let base_text_changed =
2170            snapshot
2171                .diffs
2172                .get(&buffer_id)
2173                .map_or(true, |diff_snapshot| {
2174                    match (&diff_snapshot.base_text, &diff.base_text) {
2175                        (None, None) => false,
2176                        (None, Some(_)) => true,
2177                        (Some(_), None) => true,
2178                        (Some(old), Some(new)) => {
2179                            let (old_id, old_empty) = (old.remote_id(), old.is_empty());
2180                            let (new_id, new_empty) = (new.remote_id(), new.is_empty());
2181                            new_id != old_id && (!new_empty || !old_empty)
2182                        }
2183                    }
2184                });
2185        snapshot.diffs.insert(buffer_id, diff);
2186
2187        let buffers = self.buffers.borrow();
2188        let Some(buffer_state) = buffers.get(&buffer_id) else {
2189            return;
2190        };
2191
2192        let diff_change_range = range.to_offset(buffer_state.buffer.read(cx));
2193
2194        let mut excerpt_edits = Vec::new();
2195        for locator in &buffer_state.excerpts {
2196            let mut cursor = snapshot
2197                .excerpts
2198                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2199            cursor.seek_forward(&Some(locator), Bias::Left, &());
2200            if let Some(excerpt) = cursor.item() {
2201                if excerpt.locator == *locator {
2202                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2203                    if diff_change_range.end < excerpt_buffer_range.start
2204                        || diff_change_range.start > excerpt_buffer_range.end
2205                    {
2206                        continue;
2207                    }
2208                    let excerpt_start = cursor.start().1;
2209                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2210                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2211                        diff_change_range
2212                            .start
2213                            .saturating_sub(excerpt_buffer_range.start),
2214                    );
2215                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2216                        diff_change_range
2217                            .end
2218                            .saturating_sub(excerpt_buffer_range.start),
2219                    );
2220                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2221                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2222                    excerpt_edits.push(Edit {
2223                        old: edit_start..edit_end,
2224                        new: edit_start..edit_end,
2225                    });
2226                }
2227            }
2228        }
2229
2230        self.sync_diff_transforms(
2231            &mut snapshot,
2232            excerpt_edits,
2233            DiffChangeKind::DiffUpdated {
2234                base_changed: base_text_changed,
2235            },
2236        );
2237        cx.emit(Event::Edited {
2238            singleton_buffer_edited: false,
2239            edited_buffer: None,
2240        });
2241    }
2242
2243    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2244        self.buffers
2245            .borrow()
2246            .values()
2247            .map(|state| state.buffer.clone())
2248            .collect()
2249    }
2250
2251    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2252        self.buffers
2253            .borrow()
2254            .get(&buffer_id)
2255            .map(|state| state.buffer.clone())
2256    }
2257
2258    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2259        self.point_to_buffer_offset(point, cx)
2260            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2261    }
2262
2263    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2264        let mut language = None;
2265        let mut file = None;
2266        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2267            let buffer = buffer.read(cx);
2268            language = buffer.language_at(offset);
2269            file = buffer.file();
2270        }
2271        language_settings(language.map(|l| l.name()), file, cx)
2272    }
2273
2274    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2275        self.buffers
2276            .borrow()
2277            .values()
2278            .for_each(|state| f(&state.buffer))
2279    }
2280
2281    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2282        if let Some(title) = self.title.as_ref() {
2283            return title.into();
2284        }
2285
2286        if let Some(buffer) = self.as_singleton() {
2287            if let Some(file) = buffer.read(cx).file() {
2288                return file.file_name(cx).to_string_lossy();
2289            }
2290        }
2291
2292        "untitled".into()
2293    }
2294
2295    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2296        self.title = Some(title);
2297        cx.notify();
2298    }
2299
2300    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2301    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2302        for buffer_state in self.buffers.borrow().values() {
2303            buffer_state
2304                .buffer
2305                .update(cx, |buffer, _cx| buffer.refresh_preview());
2306        }
2307    }
2308
2309    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2310    pub fn preserve_preview(&self, cx: &App) -> bool {
2311        self.buffers
2312            .borrow()
2313            .values()
2314            .all(|state| state.buffer.read(cx).preserve_preview())
2315    }
2316
2317    #[cfg(any(test, feature = "test-support"))]
2318    pub fn is_parsing(&self, cx: &App) -> bool {
2319        self.as_singleton().unwrap().read(cx).is_parsing()
2320    }
2321
2322    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2323        let buffer_id = diff.read(cx).buffer_id;
2324        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2325        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2326    }
2327
2328    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2329        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2330    }
2331
2332    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2333        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2334    }
2335
2336    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2337        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2338    }
2339
2340    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2341        self.all_diff_hunks_expanded = true;
2342        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2343    }
2344
2345    pub fn all_diff_hunks_expanded(&mut self) -> bool {
2346        self.all_diff_hunks_expanded
2347    }
2348
2349    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2350        self.read(cx)
2351            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2352            .nth(1)
2353            .is_some()
2354    }
2355
2356    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2357        let snapshot = self.read(cx);
2358        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2359        for range in ranges {
2360            let range = range.to_point(&snapshot);
2361            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2362            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2363            let start = start.saturating_sub(1);
2364            let end = snapshot.len().min(end + 1);
2365            cursor.seek(&start, Bias::Right, &());
2366            while let Some(item) = cursor.item() {
2367                if *cursor.start() >= end {
2368                    break;
2369                }
2370                if item.hunk_anchor().is_some() {
2371                    return true;
2372                }
2373                cursor.next(&());
2374            }
2375        }
2376        false
2377    }
2378
2379    fn expand_or_collapse_diff_hunks(
2380        &mut self,
2381        ranges: Vec<Range<Anchor>>,
2382        expand: bool,
2383        cx: &mut Context<Self>,
2384    ) {
2385        self.sync(cx);
2386        let mut snapshot = self.snapshot.borrow_mut();
2387        let mut excerpt_edits = Vec::new();
2388        for range in ranges.iter() {
2389            let end_excerpt_id = range.end.excerpt_id;
2390            let range = range.to_point(&snapshot);
2391            let mut peek_end = range.end;
2392            if range.end.row < snapshot.max_row().0 {
2393                peek_end = Point::new(range.end.row + 1, 0);
2394            };
2395
2396            for diff_hunk in snapshot.diff_hunks_in_range(range.start..peek_end) {
2397                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2398                    continue;
2399                }
2400                let start = Anchor::in_buffer(
2401                    diff_hunk.excerpt_id,
2402                    diff_hunk.buffer_id,
2403                    diff_hunk.buffer_range.start,
2404                );
2405                let end = Anchor::in_buffer(
2406                    diff_hunk.excerpt_id,
2407                    diff_hunk.buffer_id,
2408                    diff_hunk.buffer_range.end,
2409                );
2410                let start = snapshot.excerpt_offset_for_anchor(&start);
2411                let end = snapshot.excerpt_offset_for_anchor(&end);
2412                excerpt_edits.push(text::Edit {
2413                    old: start..end,
2414                    new: start..end,
2415                });
2416            }
2417        }
2418
2419        self.sync_diff_transforms(
2420            &mut snapshot,
2421            excerpt_edits,
2422            DiffChangeKind::ExpandOrCollapseHunks { expand },
2423        );
2424        cx.emit(Event::DiffHunksToggled);
2425        cx.emit(Event::Edited {
2426            singleton_buffer_edited: false,
2427            edited_buffer: None,
2428        });
2429    }
2430
2431    pub fn resize_excerpt(
2432        &mut self,
2433        id: ExcerptId,
2434        range: Range<text::Anchor>,
2435        cx: &mut Context<Self>,
2436    ) {
2437        self.sync(cx);
2438
2439        let mut snapshot = self.snapshot.borrow_mut();
2440        let locator = snapshot.excerpt_locator_for_id(id);
2441        let mut new_excerpts = SumTree::default();
2442        let mut cursor = snapshot
2443            .excerpts
2444            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2445        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2446
2447        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2448        new_excerpts.append(prefix, &());
2449
2450        let mut excerpt = cursor.item().unwrap().clone();
2451        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2452
2453        excerpt.range.context.start = range.start;
2454        excerpt.range.context.end = range.end;
2455        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2456
2457        excerpt.text_summary = excerpt
2458            .buffer
2459            .text_summary_for_range(excerpt.range.context.clone());
2460
2461        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2462        let old_start_offset = cursor.start().1;
2463        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2464        let edit = Edit {
2465            old: old_start_offset..old_start_offset + old_text_len,
2466            new: new_start_offset..new_start_offset + new_text_len,
2467        };
2468
2469        if let Some(last_edit) = edits.last_mut() {
2470            if last_edit.old.end == edit.old.start {
2471                last_edit.old.end = edit.old.end;
2472                last_edit.new.end = edit.new.end;
2473            } else {
2474                edits.push(edit);
2475            }
2476        } else {
2477            edits.push(edit);
2478        }
2479
2480        new_excerpts.push(excerpt, &());
2481
2482        cursor.next(&());
2483
2484        new_excerpts.append(cursor.suffix(&()), &());
2485
2486        drop(cursor);
2487        snapshot.excerpts = new_excerpts;
2488
2489        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2490        cx.emit(Event::Edited {
2491            singleton_buffer_edited: false,
2492            edited_buffer: None,
2493        });
2494        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2495        cx.notify();
2496    }
2497
2498    pub fn expand_excerpts(
2499        &mut self,
2500        ids: impl IntoIterator<Item = ExcerptId>,
2501        line_count: u32,
2502        direction: ExpandExcerptDirection,
2503        cx: &mut Context<Self>,
2504    ) {
2505        if line_count == 0 {
2506            return;
2507        }
2508        self.sync(cx);
2509        let mut snapshot = self.snapshot.borrow_mut();
2510
2511        let ids = ids.into_iter().collect::<Vec<_>>();
2512        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2513        let mut new_excerpts = SumTree::default();
2514        let mut cursor = snapshot
2515            .excerpts
2516            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2517        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2518
2519        for locator in &locators {
2520            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2521            new_excerpts.append(prefix, &());
2522
2523            let mut excerpt = cursor.item().unwrap().clone();
2524            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2525
2526            let up_line_count = if direction.should_expand_up() {
2527                line_count
2528            } else {
2529                0
2530            };
2531
2532            let start_row = excerpt
2533                .range
2534                .context
2535                .start
2536                .to_point(&excerpt.buffer)
2537                .row
2538                .saturating_sub(up_line_count);
2539            let start_point = Point::new(start_row, 0);
2540            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2541
2542            let down_line_count = if direction.should_expand_down() {
2543                line_count
2544            } else {
2545                0
2546            };
2547
2548            let mut end_point = excerpt.buffer.clip_point(
2549                excerpt.range.context.end.to_point(&excerpt.buffer)
2550                    + Point::new(down_line_count, 0),
2551                Bias::Left,
2552            );
2553            end_point.column = excerpt.buffer.line_len(end_point.row);
2554            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2555            excerpt.max_buffer_row = end_point.row;
2556
2557            excerpt.text_summary = excerpt
2558                .buffer
2559                .text_summary_for_range(excerpt.range.context.clone());
2560
2561            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2562            let old_start_offset = cursor.start().1;
2563            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2564            let edit = Edit {
2565                old: old_start_offset..old_start_offset + old_text_len,
2566                new: new_start_offset..new_start_offset + new_text_len,
2567            };
2568
2569            if let Some(last_edit) = edits.last_mut() {
2570                if last_edit.old.end == edit.old.start {
2571                    last_edit.old.end = edit.old.end;
2572                    last_edit.new.end = edit.new.end;
2573                } else {
2574                    edits.push(edit);
2575                }
2576            } else {
2577                edits.push(edit);
2578            }
2579
2580            new_excerpts.push(excerpt, &());
2581
2582            cursor.next(&());
2583        }
2584
2585        new_excerpts.append(cursor.suffix(&()), &());
2586
2587        drop(cursor);
2588        snapshot.excerpts = new_excerpts;
2589
2590        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2591        cx.emit(Event::Edited {
2592            singleton_buffer_edited: false,
2593            edited_buffer: None,
2594        });
2595        cx.emit(Event::ExcerptsExpanded { ids });
2596        cx.notify();
2597    }
2598
2599    fn sync(&self, cx: &App) {
2600        let mut snapshot = self.snapshot.borrow_mut();
2601        let mut excerpts_to_edit = Vec::new();
2602        let mut non_text_state_updated = false;
2603        let mut is_dirty = false;
2604        let mut has_deleted_file = false;
2605        let mut has_conflict = false;
2606        let mut edited = false;
2607        let mut buffers = self.buffers.borrow_mut();
2608        for buffer_state in buffers.values_mut() {
2609            let buffer = buffer_state.buffer.read(cx);
2610            let version = buffer.version();
2611            let non_text_state_update_count = buffer.non_text_state_update_count();
2612
2613            let buffer_edited = version.changed_since(&buffer_state.last_version);
2614            let buffer_non_text_state_updated =
2615                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2616            if buffer_edited || buffer_non_text_state_updated {
2617                buffer_state.last_version = version;
2618                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2619                excerpts_to_edit.extend(
2620                    buffer_state
2621                        .excerpts
2622                        .iter()
2623                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2624                );
2625            }
2626
2627            edited |= buffer_edited;
2628            non_text_state_updated |= buffer_non_text_state_updated;
2629            is_dirty |= buffer.is_dirty();
2630            has_deleted_file |= buffer
2631                .file()
2632                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2633            has_conflict |= buffer.has_conflict();
2634        }
2635        if edited {
2636            snapshot.edit_count += 1;
2637        }
2638        if non_text_state_updated {
2639            snapshot.non_text_state_update_count += 1;
2640        }
2641        snapshot.is_dirty = is_dirty;
2642        snapshot.has_deleted_file = has_deleted_file;
2643        snapshot.has_conflict = has_conflict;
2644
2645        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2646
2647        let mut edits = Vec::new();
2648        let mut new_excerpts = SumTree::default();
2649        let mut cursor = snapshot
2650            .excerpts
2651            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2652
2653        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2654            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2655            let old_excerpt = cursor.item().unwrap();
2656            let buffer = buffer.read(cx);
2657            let buffer_id = buffer.remote_id();
2658
2659            let mut new_excerpt;
2660            if buffer_edited {
2661                edits.extend(
2662                    buffer
2663                        .edits_since_in_range::<usize>(
2664                            old_excerpt.buffer.version(),
2665                            old_excerpt.range.context.clone(),
2666                        )
2667                        .map(|edit| {
2668                            let excerpt_old_start = cursor.start().1;
2669                            let excerpt_new_start =
2670                                ExcerptOffset::new(new_excerpts.summary().text.len);
2671                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2672                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2673                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2674                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2675                            Edit {
2676                                old: old_start..old_end,
2677                                new: new_start..new_end,
2678                            }
2679                        }),
2680                );
2681
2682                new_excerpt = Excerpt::new(
2683                    old_excerpt.id,
2684                    locator.clone(),
2685                    buffer_id,
2686                    buffer.snapshot(),
2687                    old_excerpt.range.clone(),
2688                    old_excerpt.has_trailing_newline,
2689                );
2690            } else {
2691                new_excerpt = old_excerpt.clone();
2692                new_excerpt.buffer = buffer.snapshot();
2693            }
2694
2695            new_excerpts.push(new_excerpt, &());
2696            cursor.next(&());
2697        }
2698        new_excerpts.append(cursor.suffix(&()), &());
2699
2700        drop(cursor);
2701        snapshot.excerpts = new_excerpts;
2702
2703        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2704    }
2705
2706    fn sync_diff_transforms(
2707        &self,
2708        snapshot: &mut MultiBufferSnapshot,
2709        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2710        change_kind: DiffChangeKind,
2711    ) {
2712        if excerpt_edits.is_empty() {
2713            return;
2714        }
2715
2716        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2717        let mut old_diff_transforms = snapshot
2718            .diff_transforms
2719            .cursor::<(ExcerptOffset, usize)>(&());
2720        let mut new_diff_transforms = SumTree::default();
2721        let mut old_expanded_hunks = HashSet::default();
2722        let mut output_edits = Vec::new();
2723        let mut output_delta = 0_isize;
2724        let mut at_transform_boundary = true;
2725        let mut end_of_current_insert = None;
2726
2727        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2728        while let Some(edit) = excerpt_edits.next() {
2729            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2730            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2731                excerpts.prev(&());
2732            }
2733
2734            // Keep any transforms that are before the edit.
2735            if at_transform_boundary {
2736                at_transform_boundary = false;
2737                let transforms_before_edit =
2738                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2739                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2740                if let Some(transform) = old_diff_transforms.item() {
2741                    if old_diff_transforms.end(&()).0 == edit.old.start
2742                        && old_diff_transforms.start().0 < edit.old.start
2743                    {
2744                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2745                        old_diff_transforms.next(&());
2746                    }
2747                }
2748            }
2749
2750            // Compute the start of the edit in output coordinates.
2751            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2752            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2753            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2754
2755            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2756                &edit,
2757                &mut excerpts,
2758                &mut old_diff_transforms,
2759                &mut new_diff_transforms,
2760                &mut end_of_current_insert,
2761                &mut old_expanded_hunks,
2762                &snapshot,
2763                change_kind,
2764            );
2765
2766            // Compute the end of the edit in output coordinates.
2767            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2768            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2769            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2770            let edit_new_end =
2771                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2772            let output_edit = Edit {
2773                old: edit_old_start..edit_old_end,
2774                new: edit_new_start..edit_new_end,
2775            };
2776
2777            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2778            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2779            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2780                output_edits.push(output_edit);
2781            }
2782
2783            // If this is the last edit that intersects the current diff transform,
2784            // then recreate the content up to the end of this transform, to prepare
2785            // for reusing additional slices of the old transforms.
2786            if excerpt_edits.peek().map_or(true, |next_edit| {
2787                next_edit.old.start >= old_diff_transforms.end(&()).0
2788            }) {
2789                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2790                    && match old_diff_transforms.item() {
2791                        Some(DiffTransform::BufferContent {
2792                            inserted_hunk_anchor: Some(hunk_anchor),
2793                            ..
2794                        }) => excerpts
2795                            .item()
2796                            .is_some_and(|excerpt| hunk_anchor.1.is_valid(&excerpt.buffer)),
2797                        _ => true,
2798                    };
2799
2800                let mut excerpt_offset = edit.new.end;
2801                if !keep_next_old_transform {
2802                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2803                    old_diff_transforms.next(&());
2804                }
2805
2806                old_expanded_hunks.clear();
2807                self.push_buffer_content_transform(
2808                    &snapshot,
2809                    &mut new_diff_transforms,
2810                    excerpt_offset,
2811                    end_of_current_insert,
2812                );
2813                at_transform_boundary = true;
2814            }
2815        }
2816
2817        // Keep any transforms that are after the last edit.
2818        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2819
2820        // Ensure there's always at least one buffer content transform.
2821        if new_diff_transforms.is_empty() {
2822            new_diff_transforms.push(
2823                DiffTransform::BufferContent {
2824                    summary: Default::default(),
2825                    inserted_hunk_anchor: None,
2826                },
2827                &(),
2828            );
2829        }
2830
2831        self.subscriptions.publish(output_edits);
2832        drop(old_diff_transforms);
2833        drop(excerpts);
2834        snapshot.diff_transforms = new_diff_transforms;
2835        snapshot.edit_count += 1;
2836
2837        #[cfg(any(test, feature = "test-support"))]
2838        snapshot.check_invariants();
2839    }
2840
2841    #[allow(clippy::too_many_arguments)]
2842    fn recompute_diff_transforms_for_edit(
2843        &self,
2844        edit: &Edit<TypedOffset<Excerpt>>,
2845        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2846        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2847        new_diff_transforms: &mut SumTree<DiffTransform>,
2848        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, ExcerptId, text::Anchor)>,
2849        old_expanded_hunks: &mut HashSet<(ExcerptId, text::Anchor)>,
2850        snapshot: &MultiBufferSnapshot,
2851        change_kind: DiffChangeKind,
2852    ) -> bool {
2853        log::trace!(
2854            "recomputing diff transform for edit {:?} => {:?}",
2855            edit.old.start.value..edit.old.end.value,
2856            edit.new.start.value..edit.new.end.value
2857        );
2858
2859        // Record which hunks were previously expanded.
2860        while let Some(item) = old_diff_transforms.item() {
2861            if let Some(hunk_anchor) = item.hunk_anchor() {
2862                log::trace!(
2863                    "previously expanded hunk at {}",
2864                    old_diff_transforms.start().0
2865                );
2866                old_expanded_hunks.insert(hunk_anchor);
2867            }
2868            if old_diff_transforms.end(&()).0 > edit.old.end {
2869                break;
2870            }
2871            old_diff_transforms.next(&());
2872        }
2873
2874        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2875        if old_expanded_hunks.is_empty()
2876            && change_kind == DiffChangeKind::BufferEdited
2877            && !self.all_diff_hunks_expanded
2878        {
2879            return false;
2880        }
2881
2882        // Visit each excerpt that intersects the edit.
2883        let mut did_expand_hunks = false;
2884        while let Some(excerpt) = excerpts.item() {
2885            // Recompute the expanded hunks in the portion of the excerpt that
2886            // intersects the edit.
2887            if let Some((diff, base_text)) = snapshot
2888                .diffs
2889                .get(&excerpt.buffer_id)
2890                .and_then(|diff| Some((diff, diff.base_text.as_ref()?)))
2891            {
2892                let buffer = &excerpt.buffer;
2893                let excerpt_start = *excerpts.start();
2894                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2895                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2896                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2897                let edit_buffer_start =
2898                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2899                let edit_buffer_end =
2900                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2901                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2902                let edit_anchor_range =
2903                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2904
2905                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2906                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2907
2908                    let hunk_anchor = (excerpt.id, hunk.buffer_range.start);
2909                    if hunk_buffer_range.start < excerpt_buffer_start {
2910                        log::trace!("skipping hunk that starts before excerpt");
2911                        continue;
2912                    }
2913
2914                    let hunk_excerpt_start = excerpt_start
2915                        + ExcerptOffset::new(
2916                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2917                        );
2918                    let hunk_excerpt_end = excerpt_end.min(
2919                        excerpt_start
2920                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2921                    );
2922
2923                    self.push_buffer_content_transform(
2924                        snapshot,
2925                        new_diff_transforms,
2926                        hunk_excerpt_start,
2927                        *end_of_current_insert,
2928                    );
2929
2930                    // For every existing hunk, determine if it was previously expanded
2931                    // and if it should currently be expanded.
2932                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_anchor);
2933                    let should_expand_hunk = match &change_kind {
2934                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2935                            self.all_diff_hunks_expanded
2936                        }
2937                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2938                            let intersects = hunk_buffer_range.is_empty()
2939                                || hunk_buffer_range.end > edit_buffer_start;
2940                            if *expand {
2941                                intersects
2942                                    || was_previously_expanded
2943                                    || self.all_diff_hunks_expanded
2944                            } else {
2945                                !intersects
2946                                    && (was_previously_expanded || self.all_diff_hunks_expanded)
2947                            }
2948                        }
2949                        _ => was_previously_expanded || self.all_diff_hunks_expanded,
2950                    };
2951
2952                    if should_expand_hunk {
2953                        did_expand_hunks = true;
2954                        log::trace!(
2955                            "expanding hunk {:?}, excerpt:{:?}",
2956                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2957                            excerpt.id
2958                        );
2959
2960                        if !hunk.diff_base_byte_range.is_empty()
2961                            && hunk_buffer_range.start >= edit_buffer_start
2962                            && hunk_buffer_range.start <= excerpt_buffer_end
2963                        {
2964                            let mut text_cursor =
2965                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2966                            let mut base_text_summary =
2967                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2968
2969                            let mut has_trailing_newline = false;
2970                            if base_text_summary.last_line_chars > 0 {
2971                                base_text_summary += TextSummary::newline();
2972                                has_trailing_newline = true;
2973                            }
2974
2975                            new_diff_transforms.push(
2976                                DiffTransform::DeletedHunk {
2977                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2978                                    summary: base_text_summary,
2979                                    buffer_id: excerpt.buffer_id,
2980                                    hunk_anchor,
2981                                    has_trailing_newline,
2982                                },
2983                                &(),
2984                            );
2985                        }
2986
2987                        if !hunk_buffer_range.is_empty() {
2988                            *end_of_current_insert = Some((
2989                                hunk_excerpt_end.min(excerpt_end),
2990                                hunk_anchor.0,
2991                                hunk_anchor.1,
2992                            ));
2993                        }
2994                    }
2995                }
2996            }
2997
2998            if excerpts.end(&()) <= edit.new.end {
2999                excerpts.next(&());
3000            } else {
3001                break;
3002            }
3003        }
3004
3005        did_expand_hunks || !old_expanded_hunks.is_empty()
3006    }
3007
3008    fn append_diff_transforms(
3009        &self,
3010        new_transforms: &mut SumTree<DiffTransform>,
3011        subtree: SumTree<DiffTransform>,
3012    ) {
3013        if let Some(DiffTransform::BufferContent {
3014            inserted_hunk_anchor,
3015            summary,
3016        }) = subtree.first()
3017        {
3018            if self.extend_last_buffer_content_transform(
3019                new_transforms,
3020                *inserted_hunk_anchor,
3021                *summary,
3022            ) {
3023                let mut cursor = subtree.cursor::<()>(&());
3024                cursor.next(&());
3025                cursor.next(&());
3026                new_transforms.append(cursor.suffix(&()), &());
3027                return;
3028            }
3029        }
3030        new_transforms.append(subtree, &());
3031    }
3032
3033    fn push_diff_transform(
3034        &self,
3035        new_transforms: &mut SumTree<DiffTransform>,
3036        transform: DiffTransform,
3037    ) {
3038        if let DiffTransform::BufferContent {
3039            inserted_hunk_anchor,
3040            summary,
3041        } = transform
3042        {
3043            if self.extend_last_buffer_content_transform(
3044                new_transforms,
3045                inserted_hunk_anchor,
3046                summary,
3047            ) {
3048                return;
3049            }
3050        }
3051        new_transforms.push(transform, &());
3052    }
3053
3054    fn push_buffer_content_transform(
3055        &self,
3056        old_snapshot: &MultiBufferSnapshot,
3057        new_transforms: &mut SumTree<DiffTransform>,
3058        end_offset: ExcerptOffset,
3059        current_inserted_hunk: Option<(ExcerptOffset, ExcerptId, text::Anchor)>,
3060    ) {
3061        let inserted_region =
3062            current_inserted_hunk.map(|(insertion_end_offset, excerpt_id, anchor)| {
3063                (
3064                    end_offset.min(insertion_end_offset),
3065                    Some((excerpt_id, anchor)),
3066                )
3067            });
3068        let unchanged_region = [(end_offset, None)];
3069
3070        for (end_offset, inserted_hunk_anchor) in
3071            inserted_region.into_iter().chain(unchanged_region)
3072        {
3073            let start_offset = new_transforms.summary().excerpt_len();
3074            if end_offset <= start_offset {
3075                continue;
3076            }
3077            let summary_to_add = old_snapshot
3078                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3079
3080            if !self.extend_last_buffer_content_transform(
3081                new_transforms,
3082                inserted_hunk_anchor,
3083                summary_to_add,
3084            ) {
3085                new_transforms.push(
3086                    DiffTransform::BufferContent {
3087                        summary: summary_to_add,
3088                        inserted_hunk_anchor,
3089                    },
3090                    &(),
3091                )
3092            }
3093        }
3094    }
3095
3096    fn extend_last_buffer_content_transform(
3097        &self,
3098        new_transforms: &mut SumTree<DiffTransform>,
3099        new_inserted_hunk_anchor: Option<(ExcerptId, text::Anchor)>,
3100        summary_to_add: TextSummary,
3101    ) -> bool {
3102        let mut did_extend = false;
3103        new_transforms.update_last(
3104            |last_transform| {
3105                if let DiffTransform::BufferContent {
3106                    summary,
3107                    inserted_hunk_anchor,
3108                } = last_transform
3109                {
3110                    if *inserted_hunk_anchor == new_inserted_hunk_anchor {
3111                        *summary += summary_to_add;
3112                        did_extend = true;
3113                    }
3114                }
3115            },
3116            &(),
3117        );
3118        did_extend
3119    }
3120}
3121
3122#[cfg(any(test, feature = "test-support"))]
3123impl MultiBuffer {
3124    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3125        let buffer = cx.new(|cx| Buffer::local(text, cx));
3126        cx.new(|cx| Self::singleton(buffer, cx))
3127    }
3128
3129    pub fn build_multi<const COUNT: usize>(
3130        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3131        cx: &mut gpui::App,
3132    ) -> Entity<Self> {
3133        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3134        for (text, ranges) in excerpts {
3135            let buffer = cx.new(|cx| Buffer::local(text, cx));
3136            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3137                context: range,
3138                primary: None,
3139            });
3140            multi.update(cx, |multi, cx| {
3141                multi.push_excerpts(buffer, excerpt_ranges, cx)
3142            });
3143        }
3144
3145        multi
3146    }
3147
3148    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3149        cx.new(|cx| Self::singleton(buffer, cx))
3150    }
3151
3152    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3153        cx.new(|cx| {
3154            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3155            let mutation_count = rng.gen_range(1..=5);
3156            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3157            multibuffer
3158        })
3159    }
3160
3161    pub fn randomly_edit(
3162        &mut self,
3163        rng: &mut impl rand::Rng,
3164        edit_count: usize,
3165        cx: &mut Context<Self>,
3166    ) {
3167        use util::RandomCharIter;
3168
3169        let snapshot = self.read(cx);
3170        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3171        let mut last_end = None;
3172        for _ in 0..edit_count {
3173            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3174                break;
3175            }
3176
3177            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3178            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3179            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3180            last_end = Some(end);
3181
3182            let mut range = start..end;
3183            if rng.gen_bool(0.2) {
3184                mem::swap(&mut range.start, &mut range.end);
3185            }
3186
3187            let new_text_len = rng.gen_range(0..10);
3188            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3189
3190            edits.push((range, new_text.into()));
3191        }
3192        log::info!("mutating multi-buffer with {:?}", edits);
3193        drop(snapshot);
3194
3195        self.edit(edits, None, cx);
3196    }
3197
3198    pub fn randomly_edit_excerpts(
3199        &mut self,
3200        rng: &mut impl rand::Rng,
3201        mutation_count: usize,
3202        cx: &mut Context<Self>,
3203    ) {
3204        use rand::prelude::*;
3205        use std::env;
3206        use util::RandomCharIter;
3207
3208        let max_excerpts = env::var("MAX_EXCERPTS")
3209            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3210            .unwrap_or(5);
3211
3212        let mut buffers = Vec::new();
3213        for _ in 0..mutation_count {
3214            if rng.gen_bool(0.05) {
3215                log::info!("Clearing multi-buffer");
3216                self.clear(cx);
3217                continue;
3218            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3219                let ids = self.excerpt_ids();
3220                let mut excerpts = HashSet::default();
3221                for _ in 0..rng.gen_range(0..ids.len()) {
3222                    excerpts.extend(ids.choose(rng).copied());
3223                }
3224
3225                let line_count = rng.gen_range(0..5);
3226
3227                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3228
3229                self.expand_excerpts(
3230                    excerpts.iter().cloned(),
3231                    line_count,
3232                    ExpandExcerptDirection::UpAndDown,
3233                    cx,
3234                );
3235                continue;
3236            }
3237
3238            let excerpt_ids = self.excerpt_ids();
3239            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3240                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3241                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3242                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3243                    let buffer = buffers.last().unwrap().read(cx);
3244                    log::info!(
3245                        "Creating new buffer {} with text: {:?}",
3246                        buffer.remote_id(),
3247                        buffer.text()
3248                    );
3249                    buffers.last().unwrap().clone()
3250                } else {
3251                    self.buffers
3252                        .borrow()
3253                        .values()
3254                        .choose(rng)
3255                        .unwrap()
3256                        .buffer
3257                        .clone()
3258                };
3259
3260                let buffer = buffer_handle.read(cx);
3261                let buffer_text = buffer.text();
3262                let ranges = (0..rng.gen_range(0..5))
3263                    .map(|_| {
3264                        let end_ix =
3265                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3266                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3267                        ExcerptRange {
3268                            context: start_ix..end_ix,
3269                            primary: None,
3270                        }
3271                    })
3272                    .collect::<Vec<_>>();
3273                log::info!(
3274                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3275                    buffer_handle.read(cx).remote_id(),
3276                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3277                    ranges
3278                        .iter()
3279                        .map(|r| &buffer_text[r.context.clone()])
3280                        .collect::<Vec<_>>()
3281                );
3282
3283                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3284                log::info!("Inserted with ids: {:?}", excerpt_id);
3285            } else {
3286                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3287                let mut excerpts_to_remove = excerpt_ids
3288                    .choose_multiple(rng, remove_count)
3289                    .cloned()
3290                    .collect::<Vec<_>>();
3291                let snapshot = self.snapshot.borrow();
3292                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3293                drop(snapshot);
3294                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3295                self.remove_excerpts(excerpts_to_remove, cx);
3296            }
3297        }
3298    }
3299
3300    pub fn randomly_mutate(
3301        &mut self,
3302        rng: &mut impl rand::Rng,
3303        mutation_count: usize,
3304        cx: &mut Context<Self>,
3305    ) {
3306        use rand::prelude::*;
3307
3308        if rng.gen_bool(0.7) || self.singleton {
3309            let buffer = self
3310                .buffers
3311                .borrow()
3312                .values()
3313                .choose(rng)
3314                .map(|state| state.buffer.clone());
3315
3316            if let Some(buffer) = buffer {
3317                buffer.update(cx, |buffer, cx| {
3318                    if rng.gen() {
3319                        buffer.randomly_edit(rng, mutation_count, cx);
3320                    } else {
3321                        buffer.randomly_undo_redo(rng, cx);
3322                    }
3323                });
3324            } else {
3325                self.randomly_edit(rng, mutation_count, cx);
3326            }
3327        } else {
3328            self.randomly_edit_excerpts(rng, mutation_count, cx);
3329        }
3330
3331        self.check_invariants(cx);
3332    }
3333
3334    fn check_invariants(&self, cx: &App) {
3335        self.read(cx).check_invariants();
3336    }
3337}
3338
3339impl EventEmitter<Event> for MultiBuffer {}
3340
3341impl MultiBufferSnapshot {
3342    pub fn text(&self) -> String {
3343        self.chunks(0..self.len(), false)
3344            .map(|chunk| chunk.text)
3345            .collect()
3346    }
3347
3348    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3349        self.reversed_chunks_in_range(0..position.to_offset(self))
3350            .flat_map(|c| c.chars().rev())
3351    }
3352
3353    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3354        let mut cursor = self.cursor::<usize>();
3355        cursor.seek(&range.end);
3356        let current_chunks = cursor.region().as_ref().map(|region| {
3357            let start_overshoot = range.start.saturating_sub(region.range.start);
3358            let end_overshoot = range.end - region.range.start;
3359            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3360            let start = region.buffer_range.start + start_overshoot;
3361            region.buffer.reversed_chunks_in_range(start..end)
3362        });
3363        ReversedMultiBufferChunks {
3364            cursor,
3365            current_chunks,
3366            start: range.start,
3367            offset: range.end,
3368        }
3369    }
3370
3371    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3372        let offset = position.to_offset(self);
3373        self.text_for_range(offset..self.len())
3374            .flat_map(|chunk| chunk.chars())
3375    }
3376
3377    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3378        self.chunks(range, false).map(|chunk| chunk.text)
3379    }
3380
3381    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3382        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3383            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3384    }
3385
3386    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3387    where
3388        T: ToOffset,
3389    {
3390        let position = position.to_offset(self);
3391        position == self.clip_offset(position, Bias::Left)
3392            && self
3393                .bytes_in_range(position..self.len())
3394                .flatten()
3395                .copied()
3396                .take(needle.len())
3397                .eq(needle.bytes())
3398    }
3399
3400    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3401        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3402    }
3403
3404    pub fn diff_hunks_in_range<T: ToPoint>(
3405        &self,
3406        range: Range<T>,
3407    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3408        let query_range = range.start.to_point(self)..range.end.to_point(self);
3409        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3410            let diff = self.diffs.get(&buffer.remote_id())?;
3411            let buffer_start = buffer.anchor_before(buffer_range.start);
3412            let buffer_end = buffer.anchor_after(buffer_range.end);
3413            Some(
3414                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3415                    .map(|hunk| {
3416                        (
3417                            Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
3418                            hunk,
3419                        )
3420                    }),
3421            )
3422        })
3423        .filter_map(move |(range, hunk, excerpt)| {
3424            if range.start != range.end
3425                && range.end == query_range.start
3426                && !hunk.row_range.is_empty()
3427            {
3428                return None;
3429            }
3430            let end_row = if range.end.column == 0 {
3431                range.end.row
3432            } else {
3433                range.end.row + 1
3434            };
3435            Some(MultiBufferDiffHunk {
3436                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3437                buffer_id: excerpt.buffer_id,
3438                excerpt_id: excerpt.id,
3439                buffer_range: hunk.buffer_range.clone(),
3440                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3441            })
3442        })
3443    }
3444
3445    pub fn excerpt_ids_for_range<T: ToOffset>(
3446        &self,
3447        range: Range<T>,
3448    ) -> impl Iterator<Item = ExcerptId> + '_ {
3449        let range = range.start.to_offset(self)..range.end.to_offset(self);
3450        let mut cursor = self.cursor::<usize>();
3451        cursor.seek(&range.start);
3452        std::iter::from_fn(move || {
3453            let region = cursor.region()?;
3454            if region.range.start >= range.end {
3455                return None;
3456            }
3457            cursor.next_excerpt();
3458            Some(region.excerpt.id)
3459        })
3460    }
3461
3462    pub fn buffer_ids_for_range<T: ToOffset>(
3463        &self,
3464        range: Range<T>,
3465    ) -> impl Iterator<Item = BufferId> + '_ {
3466        let range = range.start.to_offset(self)..range.end.to_offset(self);
3467        let mut cursor = self.cursor::<usize>();
3468        cursor.seek(&range.start);
3469        std::iter::from_fn(move || {
3470            let region = cursor.region()?;
3471            if region.range.start >= range.end {
3472                return None;
3473            }
3474            cursor.next_excerpt();
3475            Some(region.excerpt.buffer_id)
3476        })
3477    }
3478
3479    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3480        &self,
3481        ranges: impl Iterator<Item = Range<T>>,
3482    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3483        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3484    }
3485
3486    pub fn range_to_buffer_ranges<T: ToOffset>(
3487        &self,
3488        range: Range<T>,
3489    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3490        let start = range.start.to_offset(&self);
3491        let end = range.end.to_offset(&self);
3492
3493        let mut cursor = self.cursor::<usize>();
3494        cursor.seek(&start);
3495
3496        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3497        while let Some(region) = cursor.region() {
3498            if region.range.start > end {
3499                break;
3500            }
3501            if region.is_main_buffer {
3502                let start_overshoot = start.saturating_sub(region.range.start);
3503                let end_overshoot = end.saturating_sub(region.range.start);
3504                let start = region
3505                    .buffer_range
3506                    .end
3507                    .min(region.buffer_range.start + start_overshoot);
3508                let end = region
3509                    .buffer_range
3510                    .end
3511                    .min(region.buffer_range.start + end_overshoot);
3512                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3513                    *excerpt_id == region.excerpt.id && prev_range.end == start
3514                }) {
3515                    prev.1.end = end;
3516                } else {
3517                    result.push((region.buffer, start..end, region.excerpt.id));
3518                }
3519            }
3520            cursor.next();
3521        }
3522        result
3523    }
3524
3525    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3526        &self,
3527        range: Range<T>,
3528    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3529        let start = range.start.to_offset(&self);
3530        let end = range.end.to_offset(&self);
3531
3532        let mut cursor = self.cursor::<usize>();
3533        cursor.seek(&start);
3534
3535        std::iter::from_fn(move || {
3536            let region = cursor.region()?;
3537            if region.range.start > end {
3538                return None;
3539            }
3540            let start_overshoot = start.saturating_sub(region.range.start);
3541            let end_overshoot = end.saturating_sub(region.range.start);
3542            let start = region
3543                .buffer_range
3544                .end
3545                .min(region.buffer_range.start + start_overshoot);
3546            let end = region
3547                .buffer_range
3548                .end
3549                .min(region.buffer_range.start + end_overshoot);
3550
3551            let region_excerpt_id = region.excerpt.id;
3552            let deleted_hunk_anchor = if region.is_main_buffer {
3553                None
3554            } else {
3555                Some(self.anchor_before(region.range.start))
3556            };
3557            let result = (
3558                region.buffer,
3559                start..end,
3560                region_excerpt_id,
3561                deleted_hunk_anchor,
3562            );
3563            cursor.next();
3564            Some(result)
3565        })
3566    }
3567
3568    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3569    /// coordinates.
3570    ///
3571    /// The given callback will be called for every excerpt intersecting the given range. It will
3572    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3573    /// The callback should return an iterator of metadata items from that buffer, each paired
3574    /// with a buffer range.
3575    ///
3576    /// The returned iterator yields each of these metadata items, paired with its range in
3577    /// multi-buffer coordinates.
3578    fn lift_buffer_metadata<'a, D, M, I>(
3579        &'a self,
3580        query_range: Range<D>,
3581        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3582    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3583    where
3584        I: Iterator<Item = (Range<D>, M)> + 'a,
3585        D: TextDimension + Ord + Sub<D, Output = D>,
3586    {
3587        let max_position = D::from_text_summary(&self.text_summary());
3588        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3589        let mut cursor = self.cursor::<D>();
3590
3591        // Find the excerpt and buffer offset where the given range ends.
3592        cursor.seek(&query_range.end);
3593        let mut range_end = None;
3594        while let Some(region) = cursor.region() {
3595            if region.is_main_buffer {
3596                let mut buffer_end = region.buffer_range.start;
3597                let overshoot = if query_range.end > region.range.start {
3598                    query_range.end - region.range.start
3599                } else {
3600                    D::default()
3601                };
3602                buffer_end.add_assign(&overshoot);
3603                range_end = Some((region.excerpt.id, buffer_end));
3604                break;
3605            }
3606            cursor.next();
3607        }
3608
3609        cursor.seek(&query_range.start);
3610
3611        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3612            if region.range.start > D::zero(&()) {
3613                cursor.prev()
3614            }
3615        }
3616
3617        iter::from_fn(move || loop {
3618            let excerpt = cursor.excerpt()?;
3619
3620            // If we have already retrieved metadata for this excerpt, continue to use it.
3621            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3622                .as_mut()
3623                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3624            {
3625                Some(metadata)
3626            }
3627            // Otherwise, compute the intersection of the input range with the excerpt's range,
3628            // and retrieve the metadata for the resulting range.
3629            else {
3630                let region = cursor.region()?;
3631                let mut buffer_start;
3632                if region.is_main_buffer {
3633                    buffer_start = region.buffer_range.start;
3634                    if query_range.start > region.range.start {
3635                        let overshoot = query_range.start - region.range.start;
3636                        buffer_start.add_assign(&overshoot);
3637                    }
3638                    buffer_start = buffer_start.min(region.buffer_range.end);
3639                } else {
3640                    buffer_start = cursor.main_buffer_position()?;
3641                };
3642                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3643                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3644                    if excerpt.id == end_excerpt_id {
3645                        buffer_end = buffer_end.min(end_buffer_offset);
3646                    }
3647                }
3648
3649                if let Some(iterator) =
3650                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3651                {
3652                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3653                } else {
3654                    None
3655                }
3656            };
3657
3658            // Visit each metadata item.
3659            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3660            {
3661                // Find the multibuffer regions that contain the start and end of
3662                // the metadata item's range.
3663                if metadata_buffer_range.start > D::default() {
3664                    while let Some(region) = cursor.region() {
3665                        if region.is_main_buffer
3666                            && (region.buffer_range.end >= metadata_buffer_range.start
3667                                || cursor.is_at_end_of_excerpt())
3668                        {
3669                            break;
3670                        }
3671                        cursor.next();
3672                    }
3673                }
3674                let start_region = cursor.region()?;
3675                while let Some(region) = cursor.region() {
3676                    if region.is_main_buffer
3677                        && (region.buffer_range.end > metadata_buffer_range.end
3678                            || cursor.is_at_end_of_excerpt())
3679                    {
3680                        break;
3681                    }
3682                    cursor.next();
3683                }
3684                let end_region = cursor.region();
3685
3686                // Convert the metadata item's range into multibuffer coordinates.
3687                let mut start_position = start_region.range.start;
3688                let region_buffer_start = start_region.buffer_range.start;
3689                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3690                {
3691                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3692                    start_position = start_position.min(start_region.range.end);
3693                }
3694
3695                let mut end_position = max_position;
3696                if let Some(end_region) = &end_region {
3697                    end_position = end_region.range.start;
3698                    debug_assert!(end_region.is_main_buffer);
3699                    let region_buffer_start = end_region.buffer_range.start;
3700                    if metadata_buffer_range.end > region_buffer_start {
3701                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3702                    }
3703                    end_position = end_position.min(end_region.range.end);
3704                }
3705
3706                if start_position <= query_range.end && end_position >= query_range.start {
3707                    return Some((start_position..end_position, metadata, excerpt));
3708                }
3709            }
3710            // When there are no more metadata items for this excerpt, move to the next excerpt.
3711            else {
3712                current_excerpt_metadata.take();
3713                cursor.next_excerpt();
3714            }
3715        })
3716    }
3717
3718    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3719        let offset = position.to_offset(self);
3720
3721        // Go to the region containing the given offset.
3722        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3723        cursor.seek(&DimensionPair {
3724            key: offset,
3725            value: None,
3726        });
3727        let mut region = cursor.region()?;
3728        if region.range.start.key == offset || !region.is_main_buffer {
3729            cursor.prev();
3730            region = cursor.region()?;
3731        }
3732
3733        // Find the corresponding buffer offset.
3734        let overshoot = if region.is_main_buffer {
3735            offset - region.range.start.key
3736        } else {
3737            0
3738        };
3739        let mut max_buffer_offset = region
3740            .buffer
3741            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3742
3743        loop {
3744            let excerpt = cursor.excerpt()?;
3745            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3746            let buffer_offset = excerpt_end.min(max_buffer_offset);
3747            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3748            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3749
3750            if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3751                for hunk in diff.hunks_intersecting_range_rev(
3752                    excerpt.range.context.start..buffer_end,
3753                    &excerpt.buffer,
3754                ) {
3755                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3756                    if hunk.row_range.end >= buffer_end_row {
3757                        continue;
3758                    }
3759
3760                    let hunk_start = Point::new(hunk.row_range.start, 0);
3761                    let hunk_end = Point::new(hunk.row_range.end, 0);
3762
3763                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3764                        key: hunk_range.start,
3765                        value: None,
3766                    });
3767
3768                    let mut region = cursor.region()?;
3769                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3770                    {
3771                        cursor.prev();
3772                        region = cursor.region()?;
3773                    }
3774
3775                    let overshoot = if region.is_main_buffer {
3776                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3777                    } else {
3778                        Point::zero()
3779                    };
3780                    let start = region.range.start.value.unwrap() + overshoot;
3781
3782                    while let Some(region) = cursor.region() {
3783                        if !region.is_main_buffer
3784                            || region.buffer_range.end.value.unwrap() <= hunk_end
3785                        {
3786                            cursor.next();
3787                        } else {
3788                            break;
3789                        }
3790                    }
3791
3792                    let end = if let Some(region) = cursor.region() {
3793                        let overshoot = if region.is_main_buffer {
3794                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3795                        } else {
3796                            Point::zero()
3797                        };
3798                        region.range.start.value.unwrap() + overshoot
3799                    } else {
3800                        self.max_point()
3801                    };
3802
3803                    return Some(MultiBufferDiffHunk {
3804                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3805                        buffer_id: excerpt.buffer_id,
3806                        excerpt_id: excerpt.id,
3807                        buffer_range: hunk.buffer_range.clone(),
3808                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3809                    });
3810                }
3811            }
3812
3813            cursor.prev_excerpt();
3814            max_buffer_offset = usize::MAX;
3815        }
3816    }
3817
3818    pub fn has_diff_hunks(&self) -> bool {
3819        self.diffs.values().any(|diff| !diff.is_empty())
3820    }
3821
3822    pub fn surrounding_word<T: ToOffset>(
3823        &self,
3824        start: T,
3825        for_completion: bool,
3826    ) -> (Range<usize>, Option<CharKind>) {
3827        let mut start = start.to_offset(self);
3828        let mut end = start;
3829        let mut next_chars = self.chars_at(start).peekable();
3830        let mut prev_chars = self.reversed_chars_at(start).peekable();
3831
3832        let classifier = self
3833            .char_classifier_at(start)
3834            .for_completion(for_completion);
3835
3836        let word_kind = cmp::max(
3837            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3838            next_chars.peek().copied().map(|c| classifier.kind(c)),
3839        );
3840
3841        for ch in prev_chars {
3842            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3843                start -= ch.len_utf8();
3844            } else {
3845                break;
3846            }
3847        }
3848
3849        for ch in next_chars {
3850            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3851                end += ch.len_utf8();
3852            } else {
3853                break;
3854            }
3855        }
3856
3857        (start..end, word_kind)
3858    }
3859
3860    pub fn is_singleton(&self) -> bool {
3861        self.singleton
3862    }
3863
3864    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3865        if self.singleton {
3866            self.excerpts
3867                .iter()
3868                .next()
3869                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3870        } else {
3871            None
3872        }
3873    }
3874
3875    pub fn len(&self) -> usize {
3876        self.diff_transforms.summary().output.len
3877    }
3878
3879    pub fn is_empty(&self) -> bool {
3880        self.excerpts.summary().text.len == 0
3881    }
3882
3883    pub fn widest_line_number(&self) -> u32 {
3884        self.excerpts.summary().widest_line_number + 1
3885    }
3886
3887    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3888        let range = range.start.to_offset(self)..range.end.to_offset(self);
3889        let mut excerpts = self.cursor::<usize>();
3890        excerpts.seek(&range.start);
3891
3892        let mut chunk;
3893        let mut has_trailing_newline;
3894        let excerpt_bytes;
3895        if let Some(region) = excerpts.region() {
3896            let mut bytes = region.buffer.bytes_in_range(
3897                region.buffer_range.start + range.start - region.range.start
3898                    ..(region.buffer_range.start + range.end - region.range.start)
3899                        .min(region.buffer_range.end),
3900            );
3901            chunk = bytes.next().unwrap_or(&[][..]);
3902            excerpt_bytes = Some(bytes);
3903            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3904            if chunk.is_empty() && has_trailing_newline {
3905                chunk = b"\n";
3906                has_trailing_newline = false;
3907            }
3908        } else {
3909            chunk = &[][..];
3910            excerpt_bytes = None;
3911            has_trailing_newline = false;
3912        };
3913
3914        MultiBufferBytes {
3915            range,
3916            cursor: excerpts,
3917            excerpt_bytes,
3918            has_trailing_newline,
3919            chunk,
3920        }
3921    }
3922
3923    pub fn reversed_bytes_in_range<T: ToOffset>(
3924        &self,
3925        range: Range<T>,
3926    ) -> ReversedMultiBufferBytes {
3927        let range = range.start.to_offset(self)..range.end.to_offset(self);
3928        let mut chunks = self.reversed_chunks_in_range(range.clone());
3929        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3930        ReversedMultiBufferBytes {
3931            range,
3932            chunks,
3933            chunk,
3934        }
3935    }
3936
3937    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3938        let mut cursor = self.cursor::<Point>();
3939        cursor.seek(&Point::new(start_row.0, 0));
3940        let mut result = MultiBufferRows {
3941            point: Point::new(0, 0),
3942            is_empty: self.excerpts.is_empty(),
3943            cursor,
3944        };
3945        result.seek(start_row);
3946        result
3947    }
3948
3949    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3950        let mut chunks = MultiBufferChunks {
3951            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3952            range: 0..0,
3953            excerpts: self.excerpts.cursor(&()),
3954            diff_transforms: self.diff_transforms.cursor(&()),
3955            diffs: &self.diffs,
3956            diff_base_chunks: None,
3957            excerpt_chunks: None,
3958            buffer_chunk: None,
3959            language_aware,
3960        };
3961        let range = range.start.to_offset(self)..range.end.to_offset(self);
3962        chunks.seek(range);
3963        chunks
3964    }
3965
3966    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3967        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3968    }
3969
3970    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3971        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3972    }
3973
3974    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3975        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3976    }
3977
3978    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3979        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3980            buffer.clip_point_utf16(Unclipped(point), bias)
3981        })
3982    }
3983
3984    pub fn offset_to_point(&self, offset: usize) -> Point {
3985        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3986    }
3987
3988    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3989        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3990    }
3991
3992    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3993        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3994    }
3995
3996    pub fn point_to_offset(&self, point: Point) -> usize {
3997        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3998    }
3999
4000    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4001        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4002    }
4003
4004    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4005        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4006    }
4007
4008    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4009        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4010    }
4011
4012    fn clip_dimension<D>(
4013        &self,
4014        position: D,
4015        bias: Bias,
4016        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4017    ) -> D
4018    where
4019        D: TextDimension + Ord + Sub<D, Output = D>,
4020    {
4021        let mut cursor = self.cursor();
4022        cursor.seek(&position);
4023        if let Some(region) = cursor.region() {
4024            if position >= region.range.end {
4025                return region.range.end;
4026            }
4027            let overshoot = position - region.range.start;
4028            let mut buffer_position = region.buffer_range.start;
4029            buffer_position.add_assign(&overshoot);
4030            let clipped_buffer_position =
4031                clip_buffer_position(&region.buffer, buffer_position, bias);
4032            let mut position = region.range.start;
4033            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4034            position
4035        } else {
4036            D::from_text_summary(&self.text_summary())
4037        }
4038    }
4039
4040    fn convert_dimension<D1, D2>(
4041        &self,
4042        key: D1,
4043        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4044    ) -> D2
4045    where
4046        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4047        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4048    {
4049        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4050        cursor.seek(&DimensionPair { key, value: None });
4051        if let Some(region) = cursor.region() {
4052            if key >= region.range.end.key {
4053                return region.range.end.value.unwrap();
4054            }
4055            let start_key = region.range.start.key;
4056            let start_value = region.range.start.value.unwrap();
4057            let buffer_start_key = region.buffer_range.start.key;
4058            let buffer_start_value = region.buffer_range.start.value.unwrap();
4059            let mut buffer_key = buffer_start_key;
4060            buffer_key.add_assign(&(key - start_key));
4061            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4062            let mut result = start_value;
4063            result.add_assign(&(buffer_value - buffer_start_value));
4064            result
4065        } else {
4066            D2::from_text_summary(&self.text_summary())
4067        }
4068    }
4069
4070    pub fn point_to_buffer_offset<T: ToOffset>(
4071        &self,
4072        point: T,
4073    ) -> Option<(&BufferSnapshot, usize)> {
4074        let offset = point.to_offset(self);
4075        let mut cursor = self.cursor::<usize>();
4076        cursor.seek(&offset);
4077        let region = cursor.region()?;
4078        let overshoot = offset - region.range.start;
4079        let buffer_offset = region.buffer_range.start + overshoot;
4080        Some((region.buffer, buffer_offset))
4081    }
4082
4083    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4084        let mut cursor = self.cursor::<Point>();
4085        cursor.seek(&point);
4086        let region = cursor.region()?;
4087        let overshoot = point - region.range.start;
4088        let buffer_offset = region.buffer_range.start + overshoot;
4089        Some((region.buffer, buffer_offset, region.is_main_buffer))
4090    }
4091
4092    pub fn suggested_indents(
4093        &self,
4094        rows: impl IntoIterator<Item = u32>,
4095        cx: &App,
4096    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4097        let mut result = BTreeMap::new();
4098
4099        let mut rows_for_excerpt = Vec::new();
4100        let mut cursor = self.cursor::<Point>();
4101        let mut rows = rows.into_iter().peekable();
4102        let mut prev_row = u32::MAX;
4103        let mut prev_language_indent_size = IndentSize::default();
4104
4105        while let Some(row) = rows.next() {
4106            cursor.seek(&Point::new(row, 0));
4107            let Some(region) = cursor.region() else {
4108                continue;
4109            };
4110
4111            // Retrieve the language and indent size once for each disjoint region being indented.
4112            let single_indent_size = if row.saturating_sub(1) == prev_row {
4113                prev_language_indent_size
4114            } else {
4115                region
4116                    .buffer
4117                    .language_indent_size_at(Point::new(row, 0), cx)
4118            };
4119            prev_language_indent_size = single_indent_size;
4120            prev_row = row;
4121
4122            let start_buffer_row = region.buffer_range.start.row;
4123            let start_multibuffer_row = region.range.start.row;
4124            let end_multibuffer_row = region.range.end.row;
4125
4126            rows_for_excerpt.push(row);
4127            while let Some(next_row) = rows.peek().copied() {
4128                if end_multibuffer_row > next_row {
4129                    rows_for_excerpt.push(next_row);
4130                    rows.next();
4131                } else {
4132                    break;
4133                }
4134            }
4135
4136            let buffer_rows = rows_for_excerpt
4137                .drain(..)
4138                .map(|row| start_buffer_row + row - start_multibuffer_row);
4139            let buffer_indents = region
4140                .buffer
4141                .suggested_indents(buffer_rows, single_indent_size);
4142            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4143                (
4144                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4145                    indent,
4146                )
4147            });
4148            result.extend(multibuffer_indents);
4149        }
4150
4151        result
4152    }
4153
4154    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4155        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4156            let mut size = buffer.indent_size_for_line(range.start.row);
4157            size.len = size
4158                .len
4159                .min(range.end.column)
4160                .saturating_sub(range.start.column);
4161            size
4162        } else {
4163            IndentSize::spaces(0)
4164        }
4165    }
4166
4167    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4168        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4169            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4170        } else {
4171            LineIndent::spaces(0)
4172        }
4173    }
4174
4175    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4176        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4177
4178        if self.settings_at(0, cx).extend_comment_on_newline {
4179            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4180                let delimiters = language_scope.line_comment_prefixes();
4181                for delimiter in delimiters {
4182                    if *self
4183                        .chars_at(Point::new(row.0, indent.len() as u32))
4184                        .take(delimiter.chars().count())
4185                        .collect::<String>()
4186                        .as_str()
4187                        == **delimiter
4188                    {
4189                        indent.push_str(&delimiter);
4190                        break;
4191                    }
4192                }
4193            }
4194        }
4195
4196        indent
4197    }
4198
4199    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4200        while row.0 > 0 {
4201            row.0 -= 1;
4202            if !self.is_line_blank(row) {
4203                return Some(row);
4204            }
4205        }
4206        None
4207    }
4208
4209    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4210        if let Some((_, range)) = self.buffer_line_for_row(row) {
4211            range.end.column - range.start.column
4212        } else {
4213            0
4214        }
4215    }
4216
4217    pub fn buffer_line_for_row(
4218        &self,
4219        row: MultiBufferRow,
4220    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4221        let mut cursor = self.cursor::<Point>();
4222        let point = Point::new(row.0, 0);
4223        cursor.seek(&point);
4224        let region = cursor.region()?;
4225        let overshoot = point.min(region.range.end) - region.range.start;
4226        let buffer_point = region.buffer_range.start + overshoot;
4227        if buffer_point.row > region.buffer_range.end.row {
4228            return None;
4229        }
4230        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4231        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4232            .min(region.buffer_range.end);
4233        Some((region.buffer, line_start..line_end))
4234    }
4235
4236    pub fn max_point(&self) -> Point {
4237        self.text_summary().lines
4238    }
4239
4240    pub fn max_row(&self) -> MultiBufferRow {
4241        MultiBufferRow(self.text_summary().lines.row)
4242    }
4243
4244    pub fn text_summary(&self) -> TextSummary {
4245        self.diff_transforms.summary().output
4246    }
4247
4248    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4249    where
4250        D: TextDimension,
4251        O: ToOffset,
4252    {
4253        let range = range.start.to_offset(self)..range.end.to_offset(self);
4254        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4255        cursor.seek(&range.start, Bias::Right, &());
4256
4257        let Some(first_transform) = cursor.item() else {
4258            return D::from_text_summary(&TextSummary::default());
4259        };
4260
4261        let diff_transform_start = cursor.start().0;
4262        let diff_transform_end = cursor.end(&()).0;
4263        let diff_start = range.start;
4264        let start_overshoot = diff_start - diff_transform_start;
4265        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4266
4267        let mut result = match first_transform {
4268            DiffTransform::BufferContent { .. } => {
4269                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4270                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4271                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4272            }
4273            DiffTransform::DeletedHunk {
4274                buffer_id,
4275                base_text_byte_range,
4276                has_trailing_newline,
4277                ..
4278            } => {
4279                let buffer_start = base_text_byte_range.start + start_overshoot;
4280                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4281                let Some(base_text) = self
4282                    .diffs
4283                    .get(buffer_id)
4284                    .and_then(|diff| diff.base_text.as_ref())
4285                else {
4286                    panic!("{:?} is in non-existent deleted hunk", range.start)
4287                };
4288
4289                let include_trailing_newline =
4290                    *has_trailing_newline && range.end >= diff_transform_end;
4291                if include_trailing_newline {
4292                    buffer_end -= 1;
4293                }
4294
4295                let mut summary =
4296                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4297
4298                if include_trailing_newline {
4299                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4300                }
4301
4302                summary
4303            }
4304        };
4305        if range.end < diff_transform_end {
4306            return result;
4307        }
4308
4309        cursor.next(&());
4310        result.add_assign(&D::from_text_summary(&cursor.summary(
4311            &range.end,
4312            Bias::Right,
4313            &(),
4314        )));
4315
4316        let Some(last_transform) = cursor.item() else {
4317            return result;
4318        };
4319
4320        let overshoot = range.end - cursor.start().0;
4321        let suffix = match last_transform {
4322            DiffTransform::BufferContent { .. } => {
4323                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4324                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4325            }
4326            DiffTransform::DeletedHunk {
4327                base_text_byte_range,
4328                buffer_id,
4329                has_trailing_newline,
4330                ..
4331            } => {
4332                let buffer_end = base_text_byte_range.start + overshoot;
4333                let Some(base_text) = self
4334                    .diffs
4335                    .get(buffer_id)
4336                    .and_then(|diff| diff.base_text.as_ref())
4337                else {
4338                    panic!("{:?} is in non-existent deleted hunk", range.end)
4339                };
4340
4341                let mut suffix = base_text
4342                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4343                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4344                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4345                }
4346                suffix
4347            }
4348        };
4349
4350        result.add_assign(&suffix);
4351        result
4352    }
4353
4354    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4355    where
4356        D: TextDimension,
4357    {
4358        // let mut range = range.start..range.end;
4359        let mut summary = D::zero(&());
4360        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4361        cursor.seek(&range.start, Bias::Right, &());
4362        if let Some(excerpt) = cursor.item() {
4363            let mut end_before_newline = cursor.end(&());
4364            if excerpt.has_trailing_newline {
4365                end_before_newline -= ExcerptOffset::new(1);
4366            }
4367
4368            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4369            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4370            let end_in_excerpt =
4371                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4372            summary.add_assign(
4373                &excerpt
4374                    .buffer
4375                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4376            );
4377
4378            if range.end > end_before_newline {
4379                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4380            }
4381
4382            cursor.next(&());
4383        }
4384
4385        if range.end > *cursor.start() {
4386            summary.add_assign(
4387                &cursor
4388                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4389                    .0,
4390            );
4391            if let Some(excerpt) = cursor.item() {
4392                range.end = cmp::max(*cursor.start(), range.end);
4393
4394                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4395                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4396                summary.add_assign(
4397                    &excerpt
4398                        .buffer
4399                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4400                );
4401            }
4402        }
4403
4404        summary
4405    }
4406
4407    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4408    where
4409        D: TextDimension + Ord + Sub<D, Output = D>,
4410    {
4411        self.summaries_for_anchors([anchor])[0]
4412    }
4413
4414    fn resolve_summary_for_anchor<D>(
4415        &self,
4416        anchor: &Anchor,
4417        excerpt_position: D,
4418        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4419    ) -> D
4420    where
4421        D: TextDimension + Ord + Sub<D, Output = D>,
4422    {
4423        loop {
4424            let transform_end_position = diff_transforms.end(&()).0 .0;
4425            let at_transform_end =
4426                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4427            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4428                diff_transforms.next(&());
4429                continue;
4430            }
4431
4432            let mut position = diff_transforms.start().1 .0;
4433            match diff_transforms.item() {
4434                Some(DiffTransform::DeletedHunk {
4435                    buffer_id,
4436                    base_text_byte_range,
4437                    ..
4438                }) => {
4439                    let mut in_deleted_hunk = false;
4440                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4441                        if let Some(base_text) = self
4442                            .diffs
4443                            .get(buffer_id)
4444                            .and_then(|diff| diff.base_text.as_ref())
4445                        {
4446                            if base_text.can_resolve(&diff_base_anchor) {
4447                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4448                                if base_text_offset >= base_text_byte_range.start
4449                                    && base_text_offset <= base_text_byte_range.end
4450                                {
4451                                    let position_in_hunk = base_text
4452                                        .text_summary_for_range::<D, _>(
4453                                            base_text_byte_range.start..base_text_offset,
4454                                        );
4455                                    position.add_assign(&position_in_hunk);
4456                                    in_deleted_hunk = true;
4457                                } else if at_transform_end {
4458                                    diff_transforms.next(&());
4459                                    continue;
4460                                }
4461                            }
4462                        }
4463                    }
4464                    if !in_deleted_hunk {
4465                        position = diff_transforms.end(&()).1 .0;
4466                    }
4467                }
4468                _ => {
4469                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4470                        diff_transforms.next(&());
4471                        continue;
4472                    }
4473                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4474                    position.add_assign(&overshoot);
4475                }
4476            }
4477
4478            return position;
4479        }
4480    }
4481
4482    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4483        let mut cursor = self
4484            .excerpts
4485            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4486        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4487
4488        cursor.seek(&Some(locator), Bias::Left, &());
4489        if cursor.item().is_none() {
4490            cursor.next(&());
4491        }
4492
4493        let mut position = cursor.start().1;
4494        if let Some(excerpt) = cursor.item() {
4495            if excerpt.id == anchor.excerpt_id {
4496                let excerpt_buffer_start = excerpt
4497                    .buffer
4498                    .offset_for_anchor(&excerpt.range.context.start);
4499                let excerpt_buffer_end =
4500                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4501                let buffer_position = cmp::min(
4502                    excerpt_buffer_end,
4503                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4504                );
4505                if buffer_position > excerpt_buffer_start {
4506                    position.value += buffer_position - excerpt_buffer_start;
4507                }
4508            }
4509        }
4510        position
4511    }
4512
4513    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4514    where
4515        D: TextDimension + Ord + Sub<D, Output = D>,
4516        I: 'a + IntoIterator<Item = &'a Anchor>,
4517    {
4518        let mut anchors = anchors.into_iter().peekable();
4519        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4520        let mut diff_transforms_cursor = self
4521            .diff_transforms
4522            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4523        diff_transforms_cursor.next(&());
4524
4525        let mut summaries = Vec::new();
4526        while let Some(anchor) = anchors.peek() {
4527            let excerpt_id = anchor.excerpt_id;
4528            let excerpt_anchors = iter::from_fn(|| {
4529                let anchor = anchors.peek()?;
4530                if anchor.excerpt_id == excerpt_id {
4531                    Some(anchors.next().unwrap())
4532                } else {
4533                    None
4534                }
4535            });
4536
4537            let locator = self.excerpt_locator_for_id(excerpt_id);
4538            cursor.seek_forward(locator, Bias::Left, &());
4539            if cursor.item().is_none() {
4540                cursor.next(&());
4541            }
4542
4543            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4544            if let Some(excerpt) = cursor.item() {
4545                if excerpt.id != excerpt_id {
4546                    let position = self.resolve_summary_for_anchor(
4547                        &Anchor::min(),
4548                        excerpt_start_position,
4549                        &mut diff_transforms_cursor,
4550                    );
4551                    summaries.extend(excerpt_anchors.map(|_| position));
4552                    continue;
4553                }
4554                let excerpt_buffer_start =
4555                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4556                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4557                for (buffer_summary, anchor) in excerpt
4558                    .buffer
4559                    .summaries_for_anchors_with_payload::<D, _, _>(
4560                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4561                    )
4562                {
4563                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4564                    let mut position = excerpt_start_position;
4565                    if summary > excerpt_buffer_start {
4566                        position.add_assign(&(summary - excerpt_buffer_start));
4567                    }
4568
4569                    if position > diff_transforms_cursor.start().0 .0 {
4570                        diff_transforms_cursor.seek_forward(
4571                            &ExcerptDimension(position),
4572                            Bias::Left,
4573                            &(),
4574                        );
4575                    }
4576
4577                    summaries.push(self.resolve_summary_for_anchor(
4578                        anchor,
4579                        position,
4580                        &mut diff_transforms_cursor,
4581                    ));
4582                }
4583            } else {
4584                diff_transforms_cursor.seek_forward(
4585                    &ExcerptDimension(excerpt_start_position),
4586                    Bias::Left,
4587                    &(),
4588                );
4589                let position = self.resolve_summary_for_anchor(
4590                    &Anchor::max(),
4591                    excerpt_start_position,
4592                    &mut diff_transforms_cursor,
4593                );
4594                summaries.extend(excerpt_anchors.map(|_| position));
4595            }
4596        }
4597
4598        summaries
4599    }
4600
4601    pub fn dimensions_from_points<'a, D>(
4602        &'a self,
4603        points: impl 'a + IntoIterator<Item = Point>,
4604    ) -> impl 'a + Iterator<Item = D>
4605    where
4606        D: TextDimension + Sub<D, Output = D>,
4607    {
4608        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4609        cursor.seek(&DimensionPair {
4610            key: Point::default(),
4611            value: None,
4612        });
4613        let mut points = points.into_iter();
4614        iter::from_fn(move || {
4615            let point = points.next()?;
4616
4617            cursor.seek_forward(&DimensionPair {
4618                key: point,
4619                value: None,
4620            });
4621
4622            if let Some(region) = cursor.region() {
4623                let overshoot = point - region.range.start.key;
4624                let buffer_point = region.buffer_range.start.key + overshoot;
4625                let mut position = region.range.start.value.unwrap();
4626                position.add_assign(
4627                    &region
4628                        .buffer
4629                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4630                );
4631                return Some(position);
4632            } else {
4633                return Some(D::from_text_summary(&self.text_summary()));
4634            }
4635        })
4636    }
4637
4638    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4639    where
4640        I: 'a + IntoIterator<Item = &'a Anchor>,
4641    {
4642        let mut anchors = anchors.into_iter().enumerate().peekable();
4643        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4644        cursor.next(&());
4645
4646        let mut result = Vec::new();
4647
4648        while let Some((_, anchor)) = anchors.peek() {
4649            let old_excerpt_id = anchor.excerpt_id;
4650
4651            // Find the location where this anchor's excerpt should be.
4652            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4653            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4654
4655            if cursor.item().is_none() {
4656                cursor.next(&());
4657            }
4658
4659            let next_excerpt = cursor.item();
4660            let prev_excerpt = cursor.prev_item();
4661
4662            // Process all of the anchors for this excerpt.
4663            while let Some((_, anchor)) = anchors.peek() {
4664                if anchor.excerpt_id != old_excerpt_id {
4665                    break;
4666                }
4667                let (anchor_ix, anchor) = anchors.next().unwrap();
4668                let mut anchor = *anchor;
4669
4670                // Leave min and max anchors unchanged if invalid or
4671                // if the old excerpt still exists at this location
4672                let mut kept_position = next_excerpt
4673                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4674                    || old_excerpt_id == ExcerptId::max()
4675                    || old_excerpt_id == ExcerptId::min();
4676
4677                // If the old excerpt no longer exists at this location, then attempt to
4678                // find an equivalent position for this anchor in an adjacent excerpt.
4679                if !kept_position {
4680                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4681                        if excerpt.contains(&anchor) {
4682                            anchor.excerpt_id = excerpt.id;
4683                            kept_position = true;
4684                            break;
4685                        }
4686                    }
4687                }
4688
4689                // If there's no adjacent excerpt that contains the anchor's position,
4690                // then report that the anchor has lost its position.
4691                if !kept_position {
4692                    anchor = if let Some(excerpt) = next_excerpt {
4693                        let mut text_anchor = excerpt
4694                            .range
4695                            .context
4696                            .start
4697                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4698                        if text_anchor
4699                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4700                            .is_gt()
4701                        {
4702                            text_anchor = excerpt.range.context.end;
4703                        }
4704                        Anchor {
4705                            buffer_id: Some(excerpt.buffer_id),
4706                            excerpt_id: excerpt.id,
4707                            text_anchor,
4708                            diff_base_anchor: None,
4709                        }
4710                    } else if let Some(excerpt) = prev_excerpt {
4711                        let mut text_anchor = excerpt
4712                            .range
4713                            .context
4714                            .end
4715                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4716                        if text_anchor
4717                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4718                            .is_lt()
4719                        {
4720                            text_anchor = excerpt.range.context.start;
4721                        }
4722                        Anchor {
4723                            buffer_id: Some(excerpt.buffer_id),
4724                            excerpt_id: excerpt.id,
4725                            text_anchor,
4726                            diff_base_anchor: None,
4727                        }
4728                    } else if anchor.text_anchor.bias == Bias::Left {
4729                        Anchor::min()
4730                    } else {
4731                        Anchor::max()
4732                    };
4733                }
4734
4735                result.push((anchor_ix, anchor, kept_position));
4736            }
4737        }
4738        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4739        result
4740    }
4741
4742    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4743        self.anchor_at(position, Bias::Left)
4744    }
4745
4746    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4747        self.anchor_at(position, Bias::Right)
4748    }
4749
4750    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4751        let offset = position.to_offset(self);
4752
4753        // Find the given position in the diff transforms. Determine the corresponding
4754        // offset in the excerpts, and whether the position is within a deleted hunk.
4755        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4756        diff_transforms.seek(&offset, Bias::Right, &());
4757
4758        if offset == diff_transforms.start().0 && bias == Bias::Left {
4759            if let Some(prev_item) = diff_transforms.prev_item() {
4760                match prev_item {
4761                    DiffTransform::DeletedHunk { .. } => {
4762                        diff_transforms.prev(&());
4763                    }
4764                    _ => {}
4765                }
4766            }
4767        }
4768        let offset_in_transform = offset - diff_transforms.start().0;
4769        let mut excerpt_offset = diff_transforms.start().1;
4770        let mut diff_base_anchor = None;
4771        if let Some(DiffTransform::DeletedHunk {
4772            buffer_id,
4773            base_text_byte_range,
4774            has_trailing_newline,
4775            ..
4776        }) = diff_transforms.item()
4777        {
4778            let base_text = self
4779                .diffs
4780                .get(buffer_id)
4781                .and_then(|diff| diff.base_text.as_ref())
4782                .expect("missing diff base");
4783            if offset_in_transform > base_text_byte_range.len() {
4784                debug_assert!(*has_trailing_newline);
4785                bias = Bias::Right;
4786            } else {
4787                diff_base_anchor = Some(
4788                    base_text.anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4789                );
4790                bias = Bias::Left;
4791            }
4792        } else {
4793            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4794        };
4795
4796        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4797            return Anchor {
4798                buffer_id: Some(buffer_id),
4799                excerpt_id: *excerpt_id,
4800                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4801                diff_base_anchor,
4802            };
4803        }
4804
4805        let mut excerpts = self
4806            .excerpts
4807            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4808        excerpts.seek(&excerpt_offset, Bias::Right, &());
4809        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4810            excerpts.prev(&());
4811        }
4812        if let Some(excerpt) = excerpts.item() {
4813            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4814            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4815                overshoot -= 1;
4816                bias = Bias::Right;
4817            }
4818
4819            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4820            let text_anchor =
4821                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4822            Anchor {
4823                buffer_id: Some(excerpt.buffer_id),
4824                excerpt_id: excerpt.id,
4825                text_anchor,
4826                diff_base_anchor,
4827            }
4828        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4829            Anchor::min()
4830        } else {
4831            Anchor::max()
4832        }
4833    }
4834
4835    /// Returns an anchor for the given excerpt and text anchor,
4836    /// returns None if the excerpt_id is no longer valid.
4837    pub fn anchor_in_excerpt(
4838        &self,
4839        excerpt_id: ExcerptId,
4840        text_anchor: text::Anchor,
4841    ) -> Option<Anchor> {
4842        let locator = self.excerpt_locator_for_id(excerpt_id);
4843        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4844        cursor.seek(locator, Bias::Left, &());
4845        if let Some(excerpt) = cursor.item() {
4846            if excerpt.id == excerpt_id {
4847                let text_anchor = excerpt.clip_anchor(text_anchor);
4848                drop(cursor);
4849                return Some(Anchor {
4850                    buffer_id: Some(excerpt.buffer_id),
4851                    excerpt_id,
4852                    text_anchor,
4853                    diff_base_anchor: None,
4854                });
4855            }
4856        }
4857        None
4858    }
4859
4860    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4861        Some(self.excerpt(excerpt_id)?.range.context.clone())
4862    }
4863
4864    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4865        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4866            true
4867        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4868            excerpt.buffer.can_resolve(&anchor.text_anchor)
4869        } else {
4870            false
4871        }
4872    }
4873
4874    pub fn excerpts(
4875        &self,
4876    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4877        self.excerpts
4878            .iter()
4879            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4880    }
4881
4882    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4883        let excerpts = self.excerpts.cursor(&());
4884        let diff_transforms = self.diff_transforms.cursor(&());
4885        MultiBufferCursor {
4886            excerpts,
4887            diff_transforms,
4888            diffs: &self.diffs,
4889            cached_region: None,
4890        }
4891    }
4892
4893    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4894        let start_locator = self.excerpt_locator_for_id(id);
4895        let mut excerpts = self
4896            .excerpts
4897            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4898        excerpts.seek(&Some(start_locator), Bias::Left, &());
4899        excerpts.prev(&());
4900
4901        let mut diff_transforms = self
4902            .diff_transforms
4903            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4904        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4905        if diff_transforms.end(&()).1 < excerpts.start().1 {
4906            diff_transforms.next(&());
4907        }
4908
4909        let excerpt = excerpts.item()?;
4910        Some(MultiBufferExcerpt {
4911            excerpt,
4912            offset: diff_transforms.start().0 .0,
4913            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4914            excerpt_offset: excerpts.start().1.clone(),
4915            diff_transforms,
4916        })
4917    }
4918
4919    pub fn excerpt_boundaries_in_range<R, T>(
4920        &self,
4921        range: R,
4922    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4923    where
4924        R: RangeBounds<T>,
4925        T: ToOffset,
4926    {
4927        let start_offset;
4928        let start = match range.start_bound() {
4929            Bound::Included(start) => {
4930                start_offset = start.to_offset(self);
4931                Bound::Included(start_offset)
4932            }
4933            Bound::Excluded(_) => {
4934                panic!("not supported")
4935            }
4936            Bound::Unbounded => {
4937                start_offset = 0;
4938                Bound::Unbounded
4939            }
4940        };
4941        let end = match range.end_bound() {
4942            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4943            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4944            Bound::Unbounded => Bound::Unbounded,
4945        };
4946        let bounds = (start, end);
4947
4948        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4949        cursor.seek(&DimensionPair {
4950            key: start_offset,
4951            value: None,
4952        });
4953
4954        if cursor
4955            .region()
4956            .is_some_and(|region| bounds.contains(&region.range.start.key))
4957        {
4958            cursor.prev_excerpt();
4959        } else {
4960            cursor.seek_to_start_of_current_excerpt();
4961        }
4962        let mut prev_region = cursor.region();
4963
4964        cursor.next_excerpt();
4965
4966        let mut visited_end = false;
4967        iter::from_fn(move || loop {
4968            if self.singleton {
4969                return None;
4970            }
4971
4972            let next_region = cursor.region();
4973            cursor.next_excerpt();
4974
4975            let next_region_start = if let Some(region) = &next_region {
4976                if !bounds.contains(&region.range.start.key) {
4977                    prev_region = next_region;
4978                    continue;
4979                }
4980                region.range.start.value.unwrap()
4981            } else {
4982                if !bounds.contains(&self.len()) {
4983                    return None;
4984                }
4985                self.max_point()
4986            };
4987            let next_region_end = if let Some(region) = cursor.region() {
4988                region.range.start.value.unwrap()
4989            } else {
4990                self.max_point()
4991            };
4992
4993            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4994                id: region.excerpt.id,
4995                buffer: region.excerpt.buffer.clone(),
4996                buffer_id: region.excerpt.buffer_id,
4997                range: region.excerpt.range.clone(),
4998                end_row: MultiBufferRow(next_region_start.row),
4999            });
5000
5001            let next = next_region.as_ref().map(|region| ExcerptInfo {
5002                id: region.excerpt.id,
5003                buffer: region.excerpt.buffer.clone(),
5004                buffer_id: region.excerpt.buffer_id,
5005                range: region.excerpt.range.clone(),
5006                end_row: if region.excerpt.has_trailing_newline {
5007                    MultiBufferRow(next_region_end.row - 1)
5008                } else {
5009                    MultiBufferRow(next_region_end.row)
5010                },
5011            });
5012
5013            if next.is_none() {
5014                if visited_end {
5015                    return None;
5016                } else {
5017                    visited_end = true;
5018                }
5019            }
5020
5021            let row = MultiBufferRow(next_region_start.row);
5022
5023            prev_region = next_region;
5024
5025            return Some(ExcerptBoundary { row, prev, next });
5026        })
5027    }
5028
5029    pub fn edit_count(&self) -> usize {
5030        self.edit_count
5031    }
5032
5033    pub fn non_text_state_update_count(&self) -> usize {
5034        self.non_text_state_update_count
5035    }
5036
5037    /// Returns the smallest enclosing bracket ranges containing the given range or
5038    /// None if no brackets contain range or the range is not contained in a single
5039    /// excerpt
5040    ///
5041    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5042    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5043        &self,
5044        range: Range<T>,
5045        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5046    ) -> Option<(Range<usize>, Range<usize>)> {
5047        let range = range.start.to_offset(self)..range.end.to_offset(self);
5048        let mut excerpt = self.excerpt_containing(range.clone())?;
5049        let buffer = excerpt.buffer();
5050        let excerpt_buffer_range = excerpt.buffer_range();
5051
5052        // Filter to ranges contained in the excerpt
5053        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5054            excerpt_buffer_range.contains(&open.start)
5055                && excerpt_buffer_range.contains(&close.end)
5056                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5057        };
5058
5059        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5060            excerpt.map_range_to_buffer(range),
5061            Some(&range_filter),
5062        )?;
5063
5064        Some((
5065            excerpt.map_range_from_buffer(open),
5066            excerpt.map_range_from_buffer(close),
5067        ))
5068    }
5069
5070    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5071    /// not contained in a single excerpt
5072    pub fn enclosing_bracket_ranges<T: ToOffset>(
5073        &self,
5074        range: Range<T>,
5075    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5076        let range = range.start.to_offset(self)..range.end.to_offset(self);
5077        let mut excerpt = self.excerpt_containing(range.clone())?;
5078
5079        Some(
5080            excerpt
5081                .buffer()
5082                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5083                .filter_map(move |(open, close)| {
5084                    if excerpt.contains_buffer_range(open.start..close.end) {
5085                        Some((
5086                            excerpt.map_range_from_buffer(open),
5087                            excerpt.map_range_from_buffer(close),
5088                        ))
5089                    } else {
5090                        None
5091                    }
5092                }),
5093        )
5094    }
5095
5096    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5097    /// not contained in a single excerpt
5098    pub fn text_object_ranges<T: ToOffset>(
5099        &self,
5100        range: Range<T>,
5101        options: TreeSitterOptions,
5102    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5103        let range = range.start.to_offset(self)..range.end.to_offset(self);
5104        self.excerpt_containing(range.clone())
5105            .map(|mut excerpt| {
5106                excerpt
5107                    .buffer()
5108                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5109                    .filter_map(move |(range, text_object)| {
5110                        if excerpt.contains_buffer_range(range.clone()) {
5111                            Some((excerpt.map_range_from_buffer(range), text_object))
5112                        } else {
5113                            None
5114                        }
5115                    })
5116            })
5117            .into_iter()
5118            .flatten()
5119    }
5120
5121    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5122    /// not contained in a single excerpt
5123    pub fn bracket_ranges<T: ToOffset>(
5124        &self,
5125        range: Range<T>,
5126    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5127        let range = range.start.to_offset(self)..range.end.to_offset(self);
5128        let mut excerpt = self.excerpt_containing(range.clone())?;
5129
5130        Some(
5131            excerpt
5132                .buffer()
5133                .bracket_ranges(excerpt.map_range_to_buffer(range))
5134                .filter_map(move |(start_bracket_range, close_bracket_range)| {
5135                    let buffer_range = start_bracket_range.start..close_bracket_range.end;
5136                    if excerpt.contains_buffer_range(buffer_range) {
5137                        Some((
5138                            excerpt.map_range_from_buffer(start_bracket_range),
5139                            excerpt.map_range_from_buffer(close_bracket_range),
5140                        ))
5141                    } else {
5142                        None
5143                    }
5144                }),
5145        )
5146    }
5147
5148    pub fn redacted_ranges<'a, T: ToOffset>(
5149        &'a self,
5150        range: Range<T>,
5151        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5152    ) -> impl Iterator<Item = Range<usize>> + 'a {
5153        let range = range.start.to_offset(self)..range.end.to_offset(self);
5154        self.lift_buffer_metadata(range, move |buffer, range| {
5155            if redaction_enabled(buffer.file()) {
5156                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5157            } else {
5158                None
5159            }
5160        })
5161        .map(|(range, _, _)| range)
5162    }
5163
5164    pub fn runnable_ranges(
5165        &self,
5166        range: Range<Anchor>,
5167    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5168        let range = range.start.to_offset(self)..range.end.to_offset(self);
5169        self.lift_buffer_metadata(range, move |buffer, range| {
5170            Some(
5171                buffer
5172                    .runnable_ranges(range.clone())
5173                    .filter(move |runnable| {
5174                        runnable.run_range.start >= range.start
5175                            && runnable.run_range.end < range.end
5176                    })
5177                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5178            )
5179        })
5180        .map(|(run_range, runnable, _)| language::RunnableRange {
5181            run_range,
5182            ..runnable
5183        })
5184    }
5185
5186    pub fn line_indents(
5187        &self,
5188        start_row: MultiBufferRow,
5189        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5190    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5191        let max_point = self.max_point();
5192        let mut cursor = self.cursor::<Point>();
5193        cursor.seek(&Point::new(start_row.0, 0));
5194        iter::from_fn(move || {
5195            let mut region = cursor.region()?;
5196            while !buffer_filter(&region.excerpt.buffer) {
5197                cursor.next();
5198                region = cursor.region()?;
5199            }
5200            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5201            let buffer_start_row =
5202                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5203
5204            let buffer_end_row = if region.is_main_buffer
5205                && (region.has_trailing_newline || region.range.end == max_point)
5206            {
5207                region.buffer_range.end.row
5208            } else {
5209                region.buffer_range.end.row.saturating_sub(1)
5210            };
5211
5212            let line_indents = region
5213                .buffer
5214                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5215            cursor.next();
5216            return Some(line_indents.map(move |(buffer_row, indent)| {
5217                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5218                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5219            }));
5220        })
5221        .flatten()
5222    }
5223
5224    pub fn reversed_line_indents(
5225        &self,
5226        end_row: MultiBufferRow,
5227        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5228    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5229        let max_point = self.max_point();
5230        let mut cursor = self.cursor::<Point>();
5231        cursor.seek(&Point::new(end_row.0, 0));
5232        iter::from_fn(move || {
5233            let mut region = cursor.region()?;
5234            while !buffer_filter(&region.excerpt.buffer) {
5235                cursor.prev();
5236                region = cursor.region()?;
5237            }
5238
5239            let buffer_start_row = region.buffer_range.start.row;
5240            let buffer_end_row = if region.is_main_buffer
5241                && (region.has_trailing_newline || region.range.end == max_point)
5242            {
5243                region.buffer_range.end.row + 1
5244            } else {
5245                region.buffer_range.end.row
5246            };
5247
5248            let overshoot = end_row.0 - region.range.start.row;
5249            let buffer_end_row =
5250                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5251
5252            let line_indents = region
5253                .buffer
5254                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5255            cursor.prev();
5256            return Some(line_indents.map(move |(buffer_row, indent)| {
5257                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5258                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5259            }));
5260        })
5261        .flatten()
5262    }
5263
5264    pub async fn enclosing_indent(
5265        &self,
5266        mut target_row: MultiBufferRow,
5267    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5268        let max_row = MultiBufferRow(self.max_point().row);
5269        if target_row >= max_row {
5270            return None;
5271        }
5272
5273        let mut target_indent = self.line_indent_for_row(target_row);
5274
5275        // If the current row is at the start of an indented block, we want to return this
5276        // block as the enclosing indent.
5277        if !target_indent.is_line_empty() && target_row < max_row {
5278            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5279            if !next_line_indent.is_line_empty()
5280                && target_indent.raw_len() < next_line_indent.raw_len()
5281            {
5282                target_indent = next_line_indent;
5283                target_row.0 += 1;
5284            }
5285        }
5286
5287        const SEARCH_ROW_LIMIT: u32 = 25000;
5288        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5289        const YIELD_INTERVAL: u32 = 100;
5290
5291        let mut accessed_row_counter = 0;
5292
5293        // If there is a blank line at the current row, search for the next non indented lines
5294        if target_indent.is_line_empty() {
5295            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5296            let end =
5297                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5298
5299            let mut non_empty_line_above = None;
5300            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5301                if row < start {
5302                    break;
5303                }
5304                accessed_row_counter += 1;
5305                if accessed_row_counter == YIELD_INTERVAL {
5306                    accessed_row_counter = 0;
5307                    yield_now().await;
5308                }
5309                if !indent.is_line_empty() {
5310                    non_empty_line_above = Some((row, indent));
5311                    break;
5312                }
5313            }
5314
5315            let mut non_empty_line_below = None;
5316            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5317                if row > end {
5318                    break;
5319                }
5320                accessed_row_counter += 1;
5321                if accessed_row_counter == YIELD_INTERVAL {
5322                    accessed_row_counter = 0;
5323                    yield_now().await;
5324                }
5325                if !indent.is_line_empty() {
5326                    non_empty_line_below = Some((row, indent));
5327                    break;
5328                }
5329            }
5330
5331            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5332                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5333                    if above_indent.raw_len() >= below_indent.raw_len() {
5334                        (above_row, above_indent)
5335                    } else {
5336                        (below_row, below_indent)
5337                    }
5338                }
5339                (Some(above), None) => above,
5340                (None, Some(below)) => below,
5341                _ => return None,
5342            };
5343
5344            target_indent = indent;
5345            target_row = row;
5346        }
5347
5348        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5349        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5350
5351        let mut start_indent = None;
5352        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5353            if row < start {
5354                break;
5355            }
5356            accessed_row_counter += 1;
5357            if accessed_row_counter == YIELD_INTERVAL {
5358                accessed_row_counter = 0;
5359                yield_now().await;
5360            }
5361            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5362                start_indent = Some((row, indent));
5363                break;
5364            }
5365        }
5366        let (start_row, start_indent_size) = start_indent?;
5367
5368        let mut end_indent = (end, None);
5369        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5370            if row > end {
5371                break;
5372            }
5373            accessed_row_counter += 1;
5374            if accessed_row_counter == YIELD_INTERVAL {
5375                accessed_row_counter = 0;
5376                yield_now().await;
5377            }
5378            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5379                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5380                break;
5381            }
5382        }
5383        let (end_row, end_indent_size) = end_indent;
5384
5385        let indent = if let Some(end_indent_size) = end_indent_size {
5386            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5387                start_indent_size
5388            } else {
5389                end_indent_size
5390            }
5391        } else {
5392            start_indent_size
5393        };
5394
5395        Some((start_row..end_row, indent))
5396    }
5397
5398    pub fn indent_guides_in_range<T: ToPoint>(
5399        &self,
5400        range: Range<T>,
5401        ignore_disabled_for_language: bool,
5402        cx: &App,
5403    ) -> impl Iterator<Item = IndentGuide> {
5404        let range = range.start.to_point(self)..range.end.to_point(self);
5405        let start_row = MultiBufferRow(range.start.row);
5406        let end_row = MultiBufferRow(range.end.row);
5407
5408        let mut row_indents = self.line_indents(start_row, |buffer| {
5409            let settings =
5410                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5411            settings.indent_guides.enabled || ignore_disabled_for_language
5412        });
5413
5414        let mut result = Vec::new();
5415        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5416
5417        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5418            if first_row > end_row {
5419                break;
5420            }
5421            let current_depth = indent_stack.len() as u32;
5422
5423            let settings =
5424                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5425            let tab_size = settings.tab_size.get() as u32;
5426
5427            // When encountering empty, continue until found useful line indent
5428            // then add to the indent stack with the depth found
5429            let mut found_indent = false;
5430            let mut last_row = first_row;
5431            if line_indent.is_line_empty() {
5432                while !found_indent {
5433                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5434                        break;
5435                    };
5436                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5437                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5438                        break;
5439                    }
5440
5441                    if new_line_indent.is_line_empty() {
5442                        continue;
5443                    }
5444                    last_row = target_row.min(end_row);
5445                    line_indent = new_line_indent;
5446                    found_indent = true;
5447                    break;
5448                }
5449            } else {
5450                found_indent = true
5451            }
5452
5453            let depth = if found_indent {
5454                line_indent.len(tab_size) / tab_size
5455                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5456            } else {
5457                current_depth
5458            };
5459
5460            match depth.cmp(&current_depth) {
5461                cmp::Ordering::Less => {
5462                    for _ in 0..(current_depth - depth) {
5463                        let mut indent = indent_stack.pop().unwrap();
5464                        if last_row != first_row {
5465                            // In this case, we landed on an empty row, had to seek forward,
5466                            // and discovered that the indent we where on is ending.
5467                            // This means that the last display row must
5468                            // be on line that ends this indent range, so we
5469                            // should display the range up to the first non-empty line
5470                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5471                        }
5472
5473                        result.push(indent)
5474                    }
5475                }
5476                cmp::Ordering::Greater => {
5477                    for next_depth in current_depth..depth {
5478                        indent_stack.push(IndentGuide {
5479                            buffer_id: buffer.remote_id(),
5480                            start_row: first_row,
5481                            end_row: last_row,
5482                            depth: next_depth,
5483                            tab_size,
5484                            settings: settings.indent_guides,
5485                        });
5486                    }
5487                }
5488                _ => {}
5489            }
5490
5491            for indent in indent_stack.iter_mut() {
5492                indent.end_row = last_row;
5493            }
5494        }
5495
5496        result.extend(indent_stack);
5497        result.into_iter()
5498    }
5499
5500    pub fn trailing_excerpt_update_count(&self) -> usize {
5501        self.trailing_excerpt_update_count
5502    }
5503
5504    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5505        self.point_to_buffer_offset(point)
5506            .and_then(|(buffer, _)| buffer.file())
5507    }
5508
5509    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5510        self.point_to_buffer_offset(point)
5511            .and_then(|(buffer, offset)| buffer.language_at(offset))
5512    }
5513
5514    pub fn settings_at<'a, T: ToOffset>(
5515        &'a self,
5516        point: T,
5517        cx: &'a App,
5518    ) -> Cow<'a, LanguageSettings> {
5519        let mut language = None;
5520        let mut file = None;
5521        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5522            language = buffer.language_at(offset);
5523            file = buffer.file();
5524        }
5525        language_settings(language.map(|l| l.name()), file, cx)
5526    }
5527
5528    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5529        self.point_to_buffer_offset(point)
5530            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5531    }
5532
5533    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5534        self.point_to_buffer_offset(point)
5535            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5536            .unwrap_or_default()
5537    }
5538
5539    pub fn language_indent_size_at<T: ToOffset>(
5540        &self,
5541        position: T,
5542        cx: &App,
5543    ) -> Option<IndentSize> {
5544        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5545        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5546    }
5547
5548    pub fn is_dirty(&self) -> bool {
5549        self.is_dirty
5550    }
5551
5552    pub fn has_deleted_file(&self) -> bool {
5553        self.has_deleted_file
5554    }
5555
5556    pub fn has_conflict(&self) -> bool {
5557        self.has_conflict
5558    }
5559
5560    pub fn has_diagnostics(&self) -> bool {
5561        self.excerpts
5562            .iter()
5563            .any(|excerpt| excerpt.buffer.has_diagnostics())
5564    }
5565
5566    pub fn diagnostic_group(
5567        &self,
5568        buffer_id: BufferId,
5569        group_id: usize,
5570    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5571        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5572            if buffer.remote_id() != buffer_id {
5573                return None;
5574            };
5575            Some(
5576                buffer
5577                    .diagnostic_group(group_id)
5578                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5579            )
5580        })
5581        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5582    }
5583
5584    pub fn diagnostics_in_range<'a, T>(
5585        &'a self,
5586        range: Range<T>,
5587    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5588    where
5589        T: 'a
5590            + text::ToOffset
5591            + text::FromAnchor
5592            + TextDimension
5593            + Ord
5594            + Sub<T, Output = T>
5595            + fmt::Debug,
5596    {
5597        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5598            Some(
5599                buffer
5600                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5601                    .map(|entry| (entry.range, entry.diagnostic)),
5602            )
5603        })
5604        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5605    }
5606
5607    pub fn syntax_ancestor<T: ToOffset>(
5608        &self,
5609        range: Range<T>,
5610    ) -> Option<(tree_sitter::Node, Range<usize>)> {
5611        let range = range.start.to_offset(self)..range.end.to_offset(self);
5612        let mut excerpt = self.excerpt_containing(range.clone())?;
5613        let node = excerpt
5614            .buffer()
5615            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5616        Some((node, excerpt.map_range_from_buffer(node.byte_range())))
5617    }
5618
5619    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5620        let (excerpt_id, _, buffer) = self.as_singleton()?;
5621        let outline = buffer.outline(theme)?;
5622        Some(Outline::new(
5623            outline
5624                .items
5625                .into_iter()
5626                .flat_map(|item| {
5627                    Some(OutlineItem {
5628                        depth: item.depth,
5629                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5630                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5631                        text: item.text,
5632                        highlight_ranges: item.highlight_ranges,
5633                        name_ranges: item.name_ranges,
5634                        body_range: item.body_range.and_then(|body_range| {
5635                            Some(
5636                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5637                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5638                            )
5639                        }),
5640                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5641                            Some(
5642                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5643                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5644                            )
5645                        }),
5646                    })
5647                })
5648                .collect(),
5649        ))
5650    }
5651
5652    pub fn symbols_containing<T: ToOffset>(
5653        &self,
5654        offset: T,
5655        theme: Option<&SyntaxTheme>,
5656    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5657        let anchor = self.anchor_before(offset);
5658        let excerpt_id = anchor.excerpt_id;
5659        let excerpt = self.excerpt(excerpt_id)?;
5660        Some((
5661            excerpt.buffer_id,
5662            excerpt
5663                .buffer
5664                .symbols_containing(anchor.text_anchor, theme)
5665                .into_iter()
5666                .flatten()
5667                .flat_map(|item| {
5668                    Some(OutlineItem {
5669                        depth: item.depth,
5670                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5671                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5672                        text: item.text,
5673                        highlight_ranges: item.highlight_ranges,
5674                        name_ranges: item.name_ranges,
5675                        body_range: item.body_range.and_then(|body_range| {
5676                            Some(
5677                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5678                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5679                            )
5680                        }),
5681                        annotation_range: item.annotation_range.and_then(|body_range| {
5682                            Some(
5683                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5684                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5685                            )
5686                        }),
5687                    })
5688                })
5689                .collect(),
5690        ))
5691    }
5692
5693    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5694        if id == ExcerptId::min() {
5695            Locator::min_ref()
5696        } else if id == ExcerptId::max() {
5697            Locator::max_ref()
5698        } else {
5699            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5700            cursor.seek(&id, Bias::Left, &());
5701            if let Some(entry) = cursor.item() {
5702                if entry.id == id {
5703                    return &entry.locator;
5704                }
5705            }
5706            panic!("invalid excerpt id {:?}", id)
5707        }
5708    }
5709
5710    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5711    fn excerpt_locators_for_ids(
5712        &self,
5713        ids: impl IntoIterator<Item = ExcerptId>,
5714    ) -> SmallVec<[Locator; 1]> {
5715        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5716        sorted_ids.sort_unstable();
5717        let mut locators = SmallVec::new();
5718
5719        while sorted_ids.last() == Some(&ExcerptId::max()) {
5720            sorted_ids.pop();
5721            if let Some(mapping) = self.excerpt_ids.last() {
5722                locators.push(mapping.locator.clone());
5723            }
5724        }
5725
5726        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5727        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5728            sorted_ids.next();
5729            if let Some(mapping) = self.excerpt_ids.first() {
5730                locators.push(mapping.locator.clone());
5731            }
5732        }
5733
5734        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5735        for id in sorted_ids {
5736            if cursor.seek_forward(&id, Bias::Left, &()) {
5737                locators.push(cursor.item().unwrap().locator.clone());
5738            } else {
5739                panic!("invalid excerpt id {:?}", id);
5740            }
5741        }
5742
5743        locators.sort_unstable();
5744        locators
5745    }
5746
5747    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5748        Some(self.excerpt(excerpt_id)?.buffer_id)
5749    }
5750
5751    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5752        Some(&self.excerpt(excerpt_id)?.buffer)
5753    }
5754
5755    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5756        let mut cursor = self
5757            .excerpts
5758            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5759        let locator = self.excerpt_locator_for_id(excerpt_id);
5760        if cursor.seek(&Some(locator), Bias::Left, &()) {
5761            let start = cursor.start().1.clone();
5762            let end = cursor.end(&()).1;
5763            let mut diff_transforms = self
5764                .diff_transforms
5765                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5766            diff_transforms.seek(&start, Bias::Left, &());
5767            let overshoot = start.0 - diff_transforms.start().0 .0;
5768            let start = diff_transforms.start().1 .0 + overshoot;
5769            diff_transforms.seek(&end, Bias::Right, &());
5770            let overshoot = end.0 - diff_transforms.start().0 .0;
5771            let end = diff_transforms.start().1 .0 + overshoot;
5772            Some(start..end)
5773        } else {
5774            None
5775        }
5776    }
5777
5778    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5779        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5780        let locator = self.excerpt_locator_for_id(excerpt_id);
5781        if cursor.seek(&Some(locator), Bias::Left, &()) {
5782            if let Some(excerpt) = cursor.item() {
5783                return Some(excerpt.range.context.clone());
5784            }
5785        }
5786        None
5787    }
5788
5789    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5790        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5791        let locator = self.excerpt_locator_for_id(excerpt_id);
5792        cursor.seek(&Some(locator), Bias::Left, &());
5793        if let Some(excerpt) = cursor.item() {
5794            if excerpt.id == excerpt_id {
5795                return Some(excerpt);
5796            }
5797        }
5798        None
5799    }
5800
5801    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5802    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5803        let range = range.start.to_offset(self)..range.end.to_offset(self);
5804        let mut cursor = self.cursor::<usize>();
5805        cursor.seek(&range.start);
5806
5807        let start_excerpt = cursor.excerpt()?;
5808        if range.end != range.start {
5809            cursor.seek_forward(&range.end);
5810            if cursor.excerpt()?.id != start_excerpt.id {
5811                return None;
5812            }
5813        }
5814
5815        cursor.seek_to_start_of_current_excerpt();
5816        let region = cursor.region()?;
5817        let offset = region.range.start;
5818        let buffer_offset = region.buffer_range.start;
5819        let excerpt_offset = cursor.excerpts.start().clone();
5820        Some(MultiBufferExcerpt {
5821            diff_transforms: cursor.diff_transforms,
5822            excerpt: start_excerpt,
5823            offset,
5824            buffer_offset,
5825            excerpt_offset,
5826        })
5827    }
5828
5829    pub fn selections_in_range<'a>(
5830        &'a self,
5831        range: &'a Range<Anchor>,
5832        include_local: bool,
5833    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5834        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5835        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5836        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5837        cursor.seek(start_locator, Bias::Left, &());
5838        cursor
5839            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5840            .flat_map(move |excerpt| {
5841                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5842                if excerpt.id == range.start.excerpt_id {
5843                    query_range.start = range.start.text_anchor;
5844                }
5845                if excerpt.id == range.end.excerpt_id {
5846                    query_range.end = range.end.text_anchor;
5847                }
5848
5849                excerpt
5850                    .buffer
5851                    .selections_in_range(query_range, include_local)
5852                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5853                        selections.map(move |selection| {
5854                            let mut start = Anchor {
5855                                buffer_id: Some(excerpt.buffer_id),
5856                                excerpt_id: excerpt.id,
5857                                text_anchor: selection.start,
5858                                diff_base_anchor: None,
5859                            };
5860                            let mut end = Anchor {
5861                                buffer_id: Some(excerpt.buffer_id),
5862                                excerpt_id: excerpt.id,
5863                                text_anchor: selection.end,
5864                                diff_base_anchor: None,
5865                            };
5866                            if range.start.cmp(&start, self).is_gt() {
5867                                start = range.start;
5868                            }
5869                            if range.end.cmp(&end, self).is_lt() {
5870                                end = range.end;
5871                            }
5872
5873                            (
5874                                replica_id,
5875                                line_mode,
5876                                cursor_shape,
5877                                Selection {
5878                                    id: selection.id,
5879                                    start,
5880                                    end,
5881                                    reversed: selection.reversed,
5882                                    goal: selection.goal,
5883                                },
5884                            )
5885                        })
5886                    })
5887            })
5888    }
5889
5890    pub fn show_headers(&self) -> bool {
5891        self.show_headers
5892    }
5893}
5894
5895#[cfg(any(test, feature = "test-support"))]
5896impl MultiBufferSnapshot {
5897    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5898        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5899        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5900        start..end
5901    }
5902
5903    #[cfg(any(test, feature = "test-support"))]
5904    fn check_invariants(&self) {
5905        let excerpts = self.excerpts.items(&());
5906        let excerpt_ids = self.excerpt_ids.items(&());
5907
5908        for (ix, excerpt) in excerpts.iter().enumerate() {
5909            if ix == 0 {
5910                if excerpt.locator <= Locator::min() {
5911                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5912                }
5913            } else if excerpt.locator <= excerpts[ix - 1].locator {
5914                panic!("excerpts are out-of-order: {:?}", excerpts);
5915            }
5916        }
5917
5918        for (ix, entry) in excerpt_ids.iter().enumerate() {
5919            if ix == 0 {
5920                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5921                    panic!("invalid first excerpt id {:?}", entry.id);
5922                }
5923            } else if entry.id <= excerpt_ids[ix - 1].id {
5924                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5925            }
5926        }
5927
5928        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5929            panic!(
5930                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5931                self.excerpts.summary().text.len,
5932                self.diff_transforms.summary().input,
5933                self.diff_transforms.items(&()),
5934            );
5935        }
5936
5937        let mut prev_transform: Option<&DiffTransform> = None;
5938        for item in self.diff_transforms.iter() {
5939            if let DiffTransform::BufferContent {
5940                summary,
5941                inserted_hunk_anchor,
5942            } = item
5943            {
5944                if let Some(DiffTransform::BufferContent {
5945                    inserted_hunk_anchor: prev_inserted_hunk_anchor,
5946                    ..
5947                }) = prev_transform
5948                {
5949                    if *inserted_hunk_anchor == *prev_inserted_hunk_anchor {
5950                        panic!(
5951                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_anchor:?}. transforms: {:+?}",
5952                            self.diff_transforms.items(&()));
5953                    }
5954                }
5955                if summary.len == 0 && !self.is_empty() {
5956                    panic!("empty buffer content transform");
5957                }
5958            }
5959            prev_transform = Some(item);
5960        }
5961    }
5962}
5963
5964impl<'a, D> MultiBufferCursor<'a, D>
5965where
5966    D: TextDimension + Ord + Sub<D, Output = D>,
5967{
5968    fn seek(&mut self, position: &D) {
5969        self.cached_region.take();
5970        self.diff_transforms
5971            .seek(&OutputDimension(*position), Bias::Right, &());
5972        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5973            self.diff_transforms.prev(&());
5974        }
5975
5976        let mut excerpt_position = self.diff_transforms.start().1 .0;
5977        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5978            let overshoot = *position - self.diff_transforms.start().0 .0;
5979            excerpt_position.add_assign(&overshoot);
5980        }
5981
5982        self.excerpts
5983            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
5984        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5985            self.excerpts.prev(&());
5986        }
5987    }
5988
5989    fn seek_forward(&mut self, position: &D) {
5990        self.cached_region.take();
5991        self.diff_transforms
5992            .seek_forward(&OutputDimension(*position), Bias::Right, &());
5993        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
5994            self.diff_transforms.prev(&());
5995        }
5996
5997        let overshoot = *position - self.diff_transforms.start().0 .0;
5998        let mut excerpt_position = self.diff_transforms.start().1 .0;
5999        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6000            excerpt_position.add_assign(&overshoot);
6001        }
6002
6003        self.excerpts
6004            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6005        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6006            self.excerpts.prev(&());
6007        }
6008    }
6009
6010    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
6011        self.cached_region.take();
6012        if let Some(excerpt) = self.excerpts.item() {
6013            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
6014            let position_in_excerpt = *position - excerpt_start;
6015            let mut excerpt_position = self.excerpts.start().0;
6016            excerpt_position.add_assign(&position_in_excerpt);
6017            self.diff_transforms
6018                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
6019            if self.diff_transforms.item().is_none() {
6020                self.diff_transforms.next(&());
6021            }
6022        }
6023    }
6024
6025    fn next_excerpt(&mut self) {
6026        self.excerpts.next(&());
6027        self.seek_to_start_of_current_excerpt();
6028    }
6029
6030    fn prev_excerpt(&mut self) {
6031        self.excerpts.prev(&());
6032        self.seek_to_start_of_current_excerpt();
6033    }
6034
6035    fn seek_to_start_of_current_excerpt(&mut self) {
6036        self.cached_region.take();
6037        self.diff_transforms
6038            .seek(self.excerpts.start(), Bias::Left, &());
6039        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6040            && self.diff_transforms.start().1 < *self.excerpts.start()
6041            && self.diff_transforms.next_item().is_some()
6042        {
6043            self.diff_transforms.next(&());
6044        }
6045    }
6046
6047    fn next(&mut self) {
6048        self.cached_region.take();
6049        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6050            cmp::Ordering::Less => self.diff_transforms.next(&()),
6051            cmp::Ordering::Greater => self.excerpts.next(&()),
6052            cmp::Ordering::Equal => {
6053                self.diff_transforms.next(&());
6054                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6055                    || self.diff_transforms.item().is_none()
6056                {
6057                    self.excerpts.next(&());
6058                }
6059            }
6060        }
6061    }
6062
6063    fn prev(&mut self) {
6064        self.cached_region.take();
6065        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6066            cmp::Ordering::Less => self.excerpts.prev(&()),
6067            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6068            cmp::Ordering::Equal => {
6069                self.diff_transforms.prev(&());
6070                if self.diff_transforms.start().1 < *self.excerpts.start()
6071                    || self.diff_transforms.item().is_none()
6072                {
6073                    self.excerpts.prev(&());
6074                }
6075            }
6076        }
6077    }
6078
6079    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6080        if self.cached_region.is_none() {
6081            self.cached_region = self.build_region();
6082        }
6083        self.cached_region.clone()
6084    }
6085
6086    fn is_at_end_of_excerpt(&mut self) -> bool {
6087        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6088            return false;
6089        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6090            || self.diff_transforms.item().is_none()
6091        {
6092            return true;
6093        }
6094
6095        self.diff_transforms.next(&());
6096        let next_transform = self.diff_transforms.item();
6097        self.diff_transforms.prev(&());
6098
6099        next_transform.map_or(true, |next_transform| {
6100            matches!(next_transform, DiffTransform::BufferContent { .. })
6101        })
6102    }
6103
6104    fn main_buffer_position(&self) -> Option<D> {
6105        let excerpt = self.excerpts.item()?;
6106        let buffer = &excerpt.buffer;
6107        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6108        let mut buffer_start = buffer_context_start;
6109        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6110        buffer_start.add_assign(&overshoot);
6111        Some(buffer_start)
6112    }
6113
6114    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6115        let excerpt = self.excerpts.item()?;
6116        match self.diff_transforms.item()? {
6117            DiffTransform::DeletedHunk {
6118                buffer_id,
6119                base_text_byte_range,
6120                has_trailing_newline,
6121                ..
6122            } => {
6123                let diff = self.diffs.get(&buffer_id)?;
6124                let buffer = diff.base_text.as_ref()?;
6125                let mut rope_cursor = buffer.as_rope().cursor(0);
6126                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6127                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6128                let mut buffer_end = buffer_start;
6129                buffer_end.add_assign(&buffer_range_len);
6130                let start = self.diff_transforms.start().0 .0;
6131                let end = self.diff_transforms.end(&()).0 .0;
6132                return Some(MultiBufferRegion {
6133                    buffer,
6134                    excerpt,
6135                    has_trailing_newline: *has_trailing_newline,
6136                    is_main_buffer: false,
6137                    is_inserted_hunk: false,
6138                    buffer_range: buffer_start..buffer_end,
6139                    range: start..end,
6140                });
6141            }
6142            DiffTransform::BufferContent {
6143                inserted_hunk_anchor,
6144                ..
6145            } => {
6146                let buffer = &excerpt.buffer;
6147                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6148
6149                let mut start = self.diff_transforms.start().0 .0;
6150                let mut buffer_start = buffer_context_start;
6151                if self.diff_transforms.start().1 < *self.excerpts.start() {
6152                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6153                    start.add_assign(&overshoot);
6154                } else {
6155                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6156                    buffer_start.add_assign(&overshoot);
6157                }
6158
6159                let mut end;
6160                let mut buffer_end;
6161                let has_trailing_newline;
6162                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6163                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6164                    end = self.diff_transforms.end(&()).0 .0;
6165                    buffer_end = buffer_context_start;
6166                    buffer_end.add_assign(&overshoot);
6167                    has_trailing_newline = false;
6168                } else {
6169                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6170                    end = self.diff_transforms.start().0 .0;
6171                    end.add_assign(&overshoot);
6172                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6173                    has_trailing_newline = excerpt.has_trailing_newline;
6174                };
6175
6176                Some(MultiBufferRegion {
6177                    buffer,
6178                    excerpt,
6179                    has_trailing_newline,
6180                    is_main_buffer: true,
6181                    is_inserted_hunk: inserted_hunk_anchor.is_some(),
6182                    buffer_range: buffer_start..buffer_end,
6183                    range: start..end,
6184                })
6185            }
6186        }
6187    }
6188
6189    fn excerpt(&self) -> Option<&'a Excerpt> {
6190        self.excerpts.item()
6191    }
6192}
6193
6194impl History {
6195    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6196        self.transaction_depth += 1;
6197        if self.transaction_depth == 1 {
6198            let id = self.next_transaction_id.tick();
6199            self.undo_stack.push(Transaction {
6200                id,
6201                buffer_transactions: Default::default(),
6202                first_edit_at: now,
6203                last_edit_at: now,
6204                suppress_grouping: false,
6205            });
6206            Some(id)
6207        } else {
6208            None
6209        }
6210    }
6211
6212    fn end_transaction(
6213        &mut self,
6214        now: Instant,
6215        buffer_transactions: HashMap<BufferId, TransactionId>,
6216    ) -> bool {
6217        assert_ne!(self.transaction_depth, 0);
6218        self.transaction_depth -= 1;
6219        if self.transaction_depth == 0 {
6220            if buffer_transactions.is_empty() {
6221                self.undo_stack.pop();
6222                false
6223            } else {
6224                self.redo_stack.clear();
6225                let transaction = self.undo_stack.last_mut().unwrap();
6226                transaction.last_edit_at = now;
6227                for (buffer_id, transaction_id) in buffer_transactions {
6228                    transaction
6229                        .buffer_transactions
6230                        .entry(buffer_id)
6231                        .or_insert(transaction_id);
6232                }
6233                true
6234            }
6235        } else {
6236            false
6237        }
6238    }
6239
6240    fn push_transaction<'a, T>(
6241        &mut self,
6242        buffer_transactions: T,
6243        now: Instant,
6244        cx: &Context<MultiBuffer>,
6245    ) where
6246        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6247    {
6248        assert_eq!(self.transaction_depth, 0);
6249        let transaction = Transaction {
6250            id: self.next_transaction_id.tick(),
6251            buffer_transactions: buffer_transactions
6252                .into_iter()
6253                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6254                .collect(),
6255            first_edit_at: now,
6256            last_edit_at: now,
6257            suppress_grouping: false,
6258        };
6259        if !transaction.buffer_transactions.is_empty() {
6260            self.undo_stack.push(transaction);
6261            self.redo_stack.clear();
6262        }
6263    }
6264
6265    fn finalize_last_transaction(&mut self) {
6266        if let Some(transaction) = self.undo_stack.last_mut() {
6267            transaction.suppress_grouping = true;
6268        }
6269    }
6270
6271    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6272        if let Some(ix) = self
6273            .undo_stack
6274            .iter()
6275            .rposition(|transaction| transaction.id == transaction_id)
6276        {
6277            Some(self.undo_stack.remove(ix))
6278        } else if let Some(ix) = self
6279            .redo_stack
6280            .iter()
6281            .rposition(|transaction| transaction.id == transaction_id)
6282        {
6283            Some(self.redo_stack.remove(ix))
6284        } else {
6285            None
6286        }
6287    }
6288
6289    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6290        self.undo_stack
6291            .iter()
6292            .find(|transaction| transaction.id == transaction_id)
6293            .or_else(|| {
6294                self.redo_stack
6295                    .iter()
6296                    .find(|transaction| transaction.id == transaction_id)
6297            })
6298    }
6299
6300    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6301        self.undo_stack
6302            .iter_mut()
6303            .find(|transaction| transaction.id == transaction_id)
6304            .or_else(|| {
6305                self.redo_stack
6306                    .iter_mut()
6307                    .find(|transaction| transaction.id == transaction_id)
6308            })
6309    }
6310
6311    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6312        assert_eq!(self.transaction_depth, 0);
6313        if let Some(transaction) = self.undo_stack.pop() {
6314            self.redo_stack.push(transaction);
6315            self.redo_stack.last_mut()
6316        } else {
6317            None
6318        }
6319    }
6320
6321    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6322        assert_eq!(self.transaction_depth, 0);
6323        if let Some(transaction) = self.redo_stack.pop() {
6324            self.undo_stack.push(transaction);
6325            self.undo_stack.last_mut()
6326        } else {
6327            None
6328        }
6329    }
6330
6331    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6332        let ix = self
6333            .undo_stack
6334            .iter()
6335            .rposition(|transaction| transaction.id == transaction_id)?;
6336        let transaction = self.undo_stack.remove(ix);
6337        self.redo_stack.push(transaction);
6338        self.redo_stack.last()
6339    }
6340
6341    fn group(&mut self) -> Option<TransactionId> {
6342        let mut count = 0;
6343        let mut transactions = self.undo_stack.iter();
6344        if let Some(mut transaction) = transactions.next_back() {
6345            while let Some(prev_transaction) = transactions.next_back() {
6346                if !prev_transaction.suppress_grouping
6347                    && transaction.first_edit_at - prev_transaction.last_edit_at
6348                        <= self.group_interval
6349                {
6350                    transaction = prev_transaction;
6351                    count += 1;
6352                } else {
6353                    break;
6354                }
6355            }
6356        }
6357        self.group_trailing(count)
6358    }
6359
6360    fn group_until(&mut self, transaction_id: TransactionId) {
6361        let mut count = 0;
6362        for transaction in self.undo_stack.iter().rev() {
6363            if transaction.id == transaction_id {
6364                self.group_trailing(count);
6365                break;
6366            } else if transaction.suppress_grouping {
6367                break;
6368            } else {
6369                count += 1;
6370            }
6371        }
6372    }
6373
6374    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6375        let new_len = self.undo_stack.len() - n;
6376        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6377        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6378            if let Some(transaction) = transactions_to_merge.last() {
6379                last_transaction.last_edit_at = transaction.last_edit_at;
6380            }
6381            for to_merge in transactions_to_merge {
6382                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6383                    last_transaction
6384                        .buffer_transactions
6385                        .entry(*buffer_id)
6386                        .or_insert(*transaction_id);
6387                }
6388            }
6389        }
6390
6391        self.undo_stack.truncate(new_len);
6392        self.undo_stack.last().map(|t| t.id)
6393    }
6394}
6395
6396impl Excerpt {
6397    fn new(
6398        id: ExcerptId,
6399        locator: Locator,
6400        buffer_id: BufferId,
6401        buffer: BufferSnapshot,
6402        range: ExcerptRange<text::Anchor>,
6403        has_trailing_newline: bool,
6404    ) -> Self {
6405        Excerpt {
6406            id,
6407            locator,
6408            max_buffer_row: range.context.end.to_point(&buffer).row,
6409            text_summary: buffer
6410                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6411            buffer_id,
6412            buffer,
6413            range,
6414            has_trailing_newline,
6415        }
6416    }
6417
6418    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6419        let content_start = self.range.context.start.to_offset(&self.buffer);
6420        let chunks_start = content_start + range.start;
6421        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6422
6423        let footer_height = if self.has_trailing_newline
6424            && range.start <= self.text_summary.len
6425            && range.end > self.text_summary.len
6426        {
6427            1
6428        } else {
6429            0
6430        };
6431
6432        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6433
6434        ExcerptChunks {
6435            excerpt_id: self.id,
6436            content_chunks,
6437            footer_height,
6438        }
6439    }
6440
6441    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6442        let content_start = self.range.context.start.to_offset(&self.buffer);
6443        let chunks_start = content_start + range.start;
6444        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6445        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6446        excerpt_chunks.footer_height = if self.has_trailing_newline
6447            && range.start <= self.text_summary.len
6448            && range.end > self.text_summary.len
6449        {
6450            1
6451        } else {
6452            0
6453        };
6454    }
6455
6456    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6457        if text_anchor
6458            .cmp(&self.range.context.start, &self.buffer)
6459            .is_lt()
6460        {
6461            self.range.context.start
6462        } else if text_anchor
6463            .cmp(&self.range.context.end, &self.buffer)
6464            .is_gt()
6465        {
6466            self.range.context.end
6467        } else {
6468            text_anchor
6469        }
6470    }
6471
6472    fn contains(&self, anchor: &Anchor) -> bool {
6473        Some(self.buffer_id) == anchor.buffer_id
6474            && self
6475                .range
6476                .context
6477                .start
6478                .cmp(&anchor.text_anchor, &self.buffer)
6479                .is_le()
6480            && self
6481                .range
6482                .context
6483                .end
6484                .cmp(&anchor.text_anchor, &self.buffer)
6485                .is_ge()
6486    }
6487
6488    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6489    fn buffer_start_offset(&self) -> usize {
6490        self.range.context.start.to_offset(&self.buffer)
6491    }
6492
6493    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6494    fn buffer_end_offset(&self) -> usize {
6495        self.buffer_start_offset() + self.text_summary.len
6496    }
6497}
6498
6499impl<'a> MultiBufferExcerpt<'a> {
6500    pub fn id(&self) -> ExcerptId {
6501        self.excerpt.id
6502    }
6503
6504    pub fn buffer_id(&self) -> BufferId {
6505        self.excerpt.buffer_id
6506    }
6507
6508    pub fn start_anchor(&self) -> Anchor {
6509        Anchor {
6510            buffer_id: Some(self.excerpt.buffer_id),
6511            excerpt_id: self.excerpt.id,
6512            text_anchor: self.excerpt.range.context.start,
6513            diff_base_anchor: None,
6514        }
6515    }
6516
6517    pub fn end_anchor(&self) -> Anchor {
6518        Anchor {
6519            buffer_id: Some(self.excerpt.buffer_id),
6520            excerpt_id: self.excerpt.id,
6521            text_anchor: self.excerpt.range.context.end,
6522            diff_base_anchor: None,
6523        }
6524    }
6525
6526    pub fn buffer(&self) -> &'a BufferSnapshot {
6527        &self.excerpt.buffer
6528    }
6529
6530    pub fn buffer_range(&self) -> Range<usize> {
6531        self.buffer_offset
6532            ..self
6533                .excerpt
6534                .range
6535                .context
6536                .end
6537                .to_offset(&self.excerpt.buffer.text)
6538    }
6539
6540    pub fn start_offset(&self) -> usize {
6541        self.offset
6542    }
6543
6544    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6545    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6546        self.map_range_to_buffer(offset..offset).start
6547    }
6548
6549    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6550    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6551        self.diff_transforms
6552            .seek(&OutputDimension(range.start), Bias::Right, &());
6553        let start = self.map_offset_to_buffer_internal(range.start);
6554        let end = if range.end > range.start {
6555            self.diff_transforms
6556                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6557            self.map_offset_to_buffer_internal(range.end)
6558        } else {
6559            start
6560        };
6561        start..end
6562    }
6563
6564    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6565        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6566        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6567            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6568        };
6569        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6570        self.buffer_offset + offset_in_excerpt
6571    }
6572
6573    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6574    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6575        self.map_range_from_buffer(buffer_offset..buffer_offset)
6576            .start
6577    }
6578
6579    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6580    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6581        let overshoot = buffer_range.start - self.buffer_offset;
6582        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6583        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6584        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6585        let start = self.diff_transforms.start().0 .0 + overshoot;
6586
6587        let end = if buffer_range.end > buffer_range.start {
6588            let overshoot = buffer_range.end - self.buffer_offset;
6589            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6590            self.diff_transforms
6591                .seek_forward(&excerpt_offset, Bias::Right, &());
6592            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6593            self.diff_transforms.start().0 .0 + overshoot
6594        } else {
6595            start
6596        };
6597
6598        start..end
6599    }
6600
6601    /// Returns true if the entirety of the given range is in the buffer's excerpt
6602    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6603        range.start >= self.excerpt.buffer_start_offset()
6604            && range.end <= self.excerpt.buffer_end_offset()
6605    }
6606
6607    pub fn max_buffer_row(&self) -> u32 {
6608        self.excerpt.max_buffer_row
6609    }
6610}
6611
6612impl ExcerptId {
6613    pub fn min() -> Self {
6614        Self(0)
6615    }
6616
6617    pub fn max() -> Self {
6618        Self(usize::MAX)
6619    }
6620
6621    pub fn to_proto(&self) -> u64 {
6622        self.0 as _
6623    }
6624
6625    pub fn from_proto(proto: u64) -> Self {
6626        Self(proto as _)
6627    }
6628
6629    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6630        let a = snapshot.excerpt_locator_for_id(*self);
6631        let b = snapshot.excerpt_locator_for_id(*other);
6632        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6633    }
6634}
6635
6636impl From<ExcerptId> for usize {
6637    fn from(val: ExcerptId) -> Self {
6638        val.0
6639    }
6640}
6641
6642impl fmt::Debug for Excerpt {
6643    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6644        f.debug_struct("Excerpt")
6645            .field("id", &self.id)
6646            .field("locator", &self.locator)
6647            .field("buffer_id", &self.buffer_id)
6648            .field("range", &self.range)
6649            .field("text_summary", &self.text_summary)
6650            .field("has_trailing_newline", &self.has_trailing_newline)
6651            .finish()
6652    }
6653}
6654
6655impl sum_tree::Item for Excerpt {
6656    type Summary = ExcerptSummary;
6657
6658    fn summary(&self, _cx: &()) -> Self::Summary {
6659        let mut text = self.text_summary;
6660        if self.has_trailing_newline {
6661            text += TextSummary::from("\n");
6662        }
6663        ExcerptSummary {
6664            excerpt_id: self.id,
6665            excerpt_locator: self.locator.clone(),
6666            widest_line_number: self.max_buffer_row,
6667            text,
6668        }
6669    }
6670}
6671
6672impl sum_tree::Item for ExcerptIdMapping {
6673    type Summary = ExcerptId;
6674
6675    fn summary(&self, _cx: &()) -> Self::Summary {
6676        self.id
6677    }
6678}
6679
6680impl sum_tree::KeyedItem for ExcerptIdMapping {
6681    type Key = ExcerptId;
6682
6683    fn key(&self) -> Self::Key {
6684        self.id
6685    }
6686}
6687
6688impl DiffTransform {
6689    fn hunk_anchor(&self) -> Option<(ExcerptId, text::Anchor)> {
6690        match self {
6691            DiffTransform::DeletedHunk { hunk_anchor, .. } => Some(*hunk_anchor),
6692            DiffTransform::BufferContent {
6693                inserted_hunk_anchor,
6694                ..
6695            } => *inserted_hunk_anchor,
6696        }
6697    }
6698}
6699
6700impl sum_tree::Item for DiffTransform {
6701    type Summary = DiffTransformSummary;
6702
6703    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6704        match self {
6705            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6706                input: *summary,
6707                output: *summary,
6708            },
6709            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6710                input: TextSummary::default(),
6711                output: *summary,
6712            },
6713        }
6714    }
6715}
6716
6717impl DiffTransformSummary {
6718    fn excerpt_len(&self) -> ExcerptOffset {
6719        ExcerptOffset::new(self.input.len)
6720    }
6721}
6722
6723impl sum_tree::Summary for DiffTransformSummary {
6724    type Context = ();
6725
6726    fn zero(_: &Self::Context) -> Self {
6727        DiffTransformSummary {
6728            input: TextSummary::default(),
6729            output: TextSummary::default(),
6730        }
6731    }
6732
6733    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6734        self.input += &summary.input;
6735        self.output += &summary.output;
6736    }
6737}
6738
6739impl sum_tree::Summary for ExcerptId {
6740    type Context = ();
6741
6742    fn zero(_cx: &()) -> Self {
6743        Default::default()
6744    }
6745
6746    fn add_summary(&mut self, other: &Self, _: &()) {
6747        *self = *other;
6748    }
6749}
6750
6751impl sum_tree::Summary for ExcerptSummary {
6752    type Context = ();
6753
6754    fn zero(_cx: &()) -> Self {
6755        Default::default()
6756    }
6757
6758    fn add_summary(&mut self, summary: &Self, _: &()) {
6759        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6760        self.excerpt_locator = summary.excerpt_locator.clone();
6761        self.text.add_summary(&summary.text, &());
6762        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6763    }
6764}
6765
6766impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6767    fn zero(_cx: &()) -> Self {
6768        Default::default()
6769    }
6770
6771    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6772        self.value += summary.text.len;
6773    }
6774}
6775
6776impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6777    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6778        Ord::cmp(&self.value, &cursor_location.text.len)
6779    }
6780}
6781
6782impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6783    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6784        Ord::cmp(&Some(self), cursor_location)
6785    }
6786}
6787
6788impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
6789    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6790        Ord::cmp(self, &cursor_location.excerpt_locator)
6791    }
6792}
6793
6794impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6795    fn zero(_cx: &()) -> Self {
6796        Default::default()
6797    }
6798
6799    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6800        self.value += summary.text.lines;
6801    }
6802}
6803
6804impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6805    for ExcerptDimension<D>
6806{
6807    fn zero(_: &()) -> Self {
6808        ExcerptDimension(D::default())
6809    }
6810
6811    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6812        self.0.add_assign(&D::from_text_summary(&summary.text))
6813    }
6814}
6815
6816impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6817    fn zero(_cx: &()) -> Self {
6818        Default::default()
6819    }
6820
6821    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6822        *self = Some(&summary.excerpt_locator);
6823    }
6824}
6825
6826impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6827    fn zero(_cx: &()) -> Self {
6828        Default::default()
6829    }
6830
6831    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6832        *self = Some(summary.excerpt_id);
6833    }
6834}
6835
6836#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6837struct ExcerptDimension<T>(T);
6838
6839#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6840struct OutputDimension<T>(T);
6841
6842impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6843    fn zero(_: &()) -> Self {
6844        ExcerptOffset::new(0)
6845    }
6846
6847    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6848        self.value += summary.input.len;
6849    }
6850}
6851
6852impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6853    fn zero(_: &()) -> Self {
6854        ExcerptPoint::new(0, 0)
6855    }
6856
6857    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6858        self.value += summary.input.lines;
6859    }
6860}
6861
6862impl<'a, D: TextDimension + Ord>
6863    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransformSummary> for ExcerptDimension<D>
6864{
6865    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6866        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6867    }
6868}
6869
6870impl<'a, D: TextDimension + Ord>
6871    sum_tree::SeekTarget<'a, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6872    for ExcerptDimension<D>
6873{
6874    fn cmp(
6875        &self,
6876        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6877        _: &(),
6878    ) -> cmp::Ordering {
6879        Ord::cmp(&self.0, &cursor_location.1 .0)
6880    }
6881}
6882
6883impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6884    fn zero(_: &()) -> Self {
6885        ExcerptDimension(D::default())
6886    }
6887
6888    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6889        self.0.add_assign(&D::from_text_summary(&summary.input))
6890    }
6891}
6892
6893impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6894    fn zero(_: &()) -> Self {
6895        OutputDimension(D::default())
6896    }
6897
6898    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6899        self.0.add_assign(&D::from_text_summary(&summary.output))
6900    }
6901}
6902
6903impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6904    fn zero(_: &()) -> Self {
6905        TextSummary::default()
6906    }
6907
6908    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6909        *self += summary.output
6910    }
6911}
6912
6913impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6914    fn zero(_: &()) -> Self {
6915        0
6916    }
6917
6918    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6919        *self += summary.output.len
6920    }
6921}
6922
6923impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6924    fn zero(_: &()) -> Self {
6925        Point::new(0, 0)
6926    }
6927
6928    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6929        *self += summary.output.lines
6930    }
6931}
6932
6933impl<'a> MultiBufferRows<'a> {
6934    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6935        self.point = Point::new(row, 0);
6936        self.cursor.seek(&self.point);
6937    }
6938}
6939
6940impl<'a> Iterator for MultiBufferRows<'a> {
6941    type Item = RowInfo;
6942
6943    fn next(&mut self) -> Option<Self::Item> {
6944        if self.is_empty && self.point.row == 0 {
6945            self.point += Point::new(1, 0);
6946            return Some(RowInfo {
6947                buffer_id: None,
6948                buffer_row: Some(0),
6949                multibuffer_row: Some(MultiBufferRow(0)),
6950                diff_status: None,
6951            });
6952        }
6953
6954        let mut region = self.cursor.region()?;
6955        while self.point >= region.range.end {
6956            self.cursor.next();
6957            if let Some(next_region) = self.cursor.region() {
6958                region = next_region;
6959            } else {
6960                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
6961                    let multibuffer_row = MultiBufferRow(self.point.row);
6962                    self.point += Point::new(1, 0);
6963                    let last_excerpt = self
6964                        .cursor
6965                        .excerpts
6966                        .item()
6967                        .or(self.cursor.excerpts.prev_item())?;
6968                    let last_row = last_excerpt
6969                        .range
6970                        .context
6971                        .end
6972                        .to_point(&last_excerpt.buffer)
6973                        .row;
6974                    return Some(RowInfo {
6975                        buffer_id: Some(last_excerpt.buffer_id),
6976                        buffer_row: Some(last_row),
6977                        multibuffer_row: Some(multibuffer_row),
6978                        diff_status: None,
6979                    });
6980                } else {
6981                    return None;
6982                }
6983            };
6984        }
6985
6986        let overshoot = self.point - region.range.start;
6987        let buffer_point = region.buffer_range.start + overshoot;
6988        let result = Some(RowInfo {
6989            buffer_id: Some(region.buffer.remote_id()),
6990            buffer_row: Some(buffer_point.row),
6991            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6992            diff_status: if region.is_inserted_hunk && self.point < region.range.end {
6993                Some(DiffHunkStatus::Added)
6994            } else if !region.is_main_buffer {
6995                Some(DiffHunkStatus::Removed)
6996            } else {
6997                None
6998            },
6999        });
7000        self.point += Point::new(1, 0);
7001        result
7002    }
7003}
7004
7005impl<'a> MultiBufferChunks<'a> {
7006    pub fn offset(&self) -> usize {
7007        self.range.start
7008    }
7009
7010    pub fn seek(&mut self, range: Range<usize>) {
7011        self.diff_transforms.seek(&range.end, Bias::Right, &());
7012        let mut excerpt_end = self.diff_transforms.start().1;
7013        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7014            let overshoot = range.end - self.diff_transforms.start().0;
7015            excerpt_end.value += overshoot;
7016        }
7017
7018        self.diff_transforms.seek(&range.start, Bias::Right, &());
7019        let mut excerpt_start = self.diff_transforms.start().1;
7020        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7021            let overshoot = range.start - self.diff_transforms.start().0;
7022            excerpt_start.value += overshoot;
7023        }
7024
7025        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7026        self.buffer_chunk.take();
7027        self.range = range;
7028    }
7029
7030    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7031        self.excerpt_offset_range = new_range.clone();
7032        self.excerpts.seek(&new_range.start, Bias::Right, &());
7033        if let Some(excerpt) = self.excerpts.item() {
7034            let excerpt_start = *self.excerpts.start();
7035            if let Some(excerpt_chunks) = self
7036                .excerpt_chunks
7037                .as_mut()
7038                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7039            {
7040                excerpt.seek_chunks(
7041                    excerpt_chunks,
7042                    (self.excerpt_offset_range.start - excerpt_start).value
7043                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7044                );
7045            } else {
7046                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7047                    (self.excerpt_offset_range.start - excerpt_start).value
7048                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7049                    self.language_aware,
7050                ));
7051            }
7052        } else {
7053            self.excerpt_chunks = None;
7054        }
7055    }
7056
7057    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7058        loop {
7059            if self.excerpt_offset_range.is_empty() {
7060                return None;
7061            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7062                self.excerpt_offset_range.start.value += chunk.text.len();
7063                return Some(chunk);
7064            } else {
7065                self.excerpts.next(&());
7066                let excerpt = self.excerpts.item()?;
7067                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7068                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7069                    self.language_aware,
7070                ));
7071            }
7072        }
7073    }
7074}
7075
7076impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7077    type Item = &'a str;
7078
7079    fn next(&mut self) -> Option<Self::Item> {
7080        let mut region = self.cursor.region()?;
7081        if self.offset == region.range.start {
7082            self.cursor.prev();
7083            region = self.cursor.region()?;
7084            let start_overshoot = self.start.saturating_sub(region.range.start);
7085            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7086                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7087            ));
7088        }
7089
7090        if self.offset == region.range.end && region.has_trailing_newline {
7091            self.offset -= 1;
7092            Some("\n")
7093        } else {
7094            let chunk = self.current_chunks.as_mut().unwrap().next().unwrap();
7095            self.offset -= chunk.len();
7096            Some(chunk)
7097        }
7098    }
7099}
7100
7101impl<'a> Iterator for MultiBufferChunks<'a> {
7102    type Item = Chunk<'a>;
7103
7104    fn next(&mut self) -> Option<Chunk<'a>> {
7105        if self.range.start >= self.range.end {
7106            return None;
7107        }
7108        if self.range.start == self.diff_transforms.end(&()).0 {
7109            self.diff_transforms.next(&());
7110        }
7111
7112        let diff_transform_start = self.diff_transforms.start().0;
7113        let diff_transform_end = self.diff_transforms.end(&()).0;
7114        debug_assert!(self.range.start < diff_transform_end);
7115
7116        let diff_transform = self.diff_transforms.item()?;
7117        match diff_transform {
7118            DiffTransform::BufferContent { .. } => {
7119                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7120                    chunk
7121                } else {
7122                    let chunk = self.next_excerpt_chunk().unwrap();
7123                    self.buffer_chunk.insert(chunk)
7124                };
7125
7126                let chunk_end = self.range.start + chunk.text.len();
7127                let diff_transform_end = diff_transform_end.min(self.range.end);
7128
7129                if diff_transform_end < chunk_end {
7130                    let (before, after) =
7131                        chunk.text.split_at(diff_transform_end - self.range.start);
7132                    self.range.start = diff_transform_end;
7133                    chunk.text = after;
7134                    Some(Chunk {
7135                        text: before,
7136                        ..chunk.clone()
7137                    })
7138                } else {
7139                    self.range.start = chunk_end;
7140                    self.buffer_chunk.take()
7141                }
7142            }
7143            DiffTransform::DeletedHunk {
7144                buffer_id,
7145                base_text_byte_range,
7146                has_trailing_newline,
7147                ..
7148            } => {
7149                let base_text_start =
7150                    base_text_byte_range.start + self.range.start - diff_transform_start;
7151                let base_text_end =
7152                    base_text_byte_range.start + self.range.end - diff_transform_start;
7153                let base_text_end = base_text_end.min(base_text_byte_range.end);
7154
7155                let mut chunks = if let Some((_, mut chunks)) = self
7156                    .diff_base_chunks
7157                    .take()
7158                    .filter(|(id, _)| id == buffer_id)
7159                {
7160                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7161                    {
7162                        chunks.seek(base_text_start..base_text_end);
7163                    }
7164                    chunks
7165                } else {
7166                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text.as_ref()?;
7167                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7168                };
7169
7170                let chunk = if let Some(chunk) = chunks.next() {
7171                    self.range.start += chunk.text.len();
7172                    self.diff_base_chunks = Some((*buffer_id, chunks));
7173                    chunk
7174                } else {
7175                    debug_assert!(has_trailing_newline);
7176                    self.range.start += "\n".len();
7177                    Chunk {
7178                        text: "\n",
7179                        ..Default::default()
7180                    }
7181                };
7182                Some(chunk)
7183            }
7184        }
7185    }
7186}
7187
7188impl<'a> MultiBufferBytes<'a> {
7189    fn consume(&mut self, len: usize) {
7190        self.range.start += len;
7191        self.chunk = &self.chunk[len..];
7192
7193        if !self.range.is_empty() && self.chunk.is_empty() {
7194            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7195                self.chunk = chunk;
7196            } else if self.has_trailing_newline {
7197                self.has_trailing_newline = false;
7198                self.chunk = b"\n";
7199            } else {
7200                self.cursor.next();
7201                if let Some(region) = self.cursor.region() {
7202                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7203                        region.buffer_range.start
7204                            ..(region.buffer_range.start + self.range.end - region.range.start)
7205                                .min(region.buffer_range.end),
7206                    );
7207                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7208                    self.excerpt_bytes = Some(excerpt_bytes);
7209                    self.has_trailing_newline =
7210                        region.has_trailing_newline && self.range.end >= region.range.end;
7211                    if self.chunk.is_empty() && self.has_trailing_newline {
7212                        self.has_trailing_newline = false;
7213                        self.chunk = b"\n";
7214                    }
7215                }
7216            }
7217        }
7218    }
7219}
7220
7221impl<'a> Iterator for MultiBufferBytes<'a> {
7222    type Item = &'a [u8];
7223
7224    fn next(&mut self) -> Option<Self::Item> {
7225        let chunk = self.chunk;
7226        if chunk.is_empty() {
7227            None
7228        } else {
7229            self.consume(chunk.len());
7230            Some(chunk)
7231        }
7232    }
7233}
7234
7235impl<'a> io::Read for MultiBufferBytes<'a> {
7236    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7237        let len = cmp::min(buf.len(), self.chunk.len());
7238        buf[..len].copy_from_slice(&self.chunk[..len]);
7239        if len > 0 {
7240            self.consume(len);
7241        }
7242        Ok(len)
7243    }
7244}
7245
7246impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
7247    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7248        let len = cmp::min(buf.len(), self.chunk.len());
7249        buf[..len].copy_from_slice(&self.chunk[..len]);
7250        buf[..len].reverse();
7251        if len > 0 {
7252            self.range.end -= len;
7253            self.chunk = &self.chunk[..self.chunk.len() - len];
7254            if !self.range.is_empty() && self.chunk.is_empty() {
7255                if let Some(chunk) = self.chunks.next() {
7256                    self.chunk = chunk.as_bytes();
7257                }
7258            }
7259        }
7260        Ok(len)
7261    }
7262}
7263
7264impl<'a> Iterator for ExcerptChunks<'a> {
7265    type Item = Chunk<'a>;
7266
7267    fn next(&mut self) -> Option<Self::Item> {
7268        if let Some(chunk) = self.content_chunks.next() {
7269            return Some(chunk);
7270        }
7271
7272        if self.footer_height > 0 {
7273            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7274            self.footer_height = 0;
7275            return Some(Chunk {
7276                text,
7277                ..Default::default()
7278            });
7279        }
7280
7281        None
7282    }
7283}
7284
7285impl ToOffset for Point {
7286    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7287        snapshot.point_to_offset(*self)
7288    }
7289}
7290
7291impl ToOffset for usize {
7292    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7293        assert!(*self <= snapshot.len(), "offset is out of range");
7294        *self
7295    }
7296}
7297
7298impl ToOffset for OffsetUtf16 {
7299    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7300        snapshot.offset_utf16_to_offset(*self)
7301    }
7302}
7303
7304impl ToOffset for PointUtf16 {
7305    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7306        snapshot.point_utf16_to_offset(*self)
7307    }
7308}
7309
7310impl ToOffsetUtf16 for OffsetUtf16 {
7311    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7312        *self
7313    }
7314}
7315
7316impl ToOffsetUtf16 for usize {
7317    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7318        snapshot.offset_to_offset_utf16(*self)
7319    }
7320}
7321
7322impl ToPoint for usize {
7323    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7324        snapshot.offset_to_point(*self)
7325    }
7326}
7327
7328impl ToPoint for Point {
7329    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7330        *self
7331    }
7332}
7333
7334impl ToPointUtf16 for usize {
7335    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7336        snapshot.offset_to_point_utf16(*self)
7337    }
7338}
7339
7340impl ToPointUtf16 for Point {
7341    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7342        snapshot.point_to_point_utf16(*self)
7343    }
7344}
7345
7346impl ToPointUtf16 for PointUtf16 {
7347    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7348        *self
7349    }
7350}
7351
7352impl From<ExcerptId> for EntityId {
7353    fn from(id: ExcerptId) -> Self {
7354        EntityId::from(id.0 as u64)
7355    }
7356}
7357
7358pub fn build_excerpt_ranges<T>(
7359    buffer: &BufferSnapshot,
7360    ranges: &[Range<T>],
7361    context_line_count: u32,
7362) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7363where
7364    T: text::ToPoint,
7365{
7366    let max_point = buffer.max_point();
7367    let mut range_counts = Vec::new();
7368    let mut excerpt_ranges = Vec::new();
7369    let mut range_iter = ranges
7370        .iter()
7371        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7372        .peekable();
7373    while let Some(range) = range_iter.next() {
7374        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7375        let row = (range.end.row + context_line_count).min(max_point.row);
7376        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7377
7378        let mut ranges_in_excerpt = 1;
7379
7380        while let Some(next_range) = range_iter.peek() {
7381            if next_range.start.row <= excerpt_end.row + context_line_count {
7382                let row = (next_range.end.row + context_line_count).min(max_point.row);
7383                excerpt_end = Point::new(row, buffer.line_len(row));
7384
7385                ranges_in_excerpt += 1;
7386                range_iter.next();
7387            } else {
7388                break;
7389            }
7390        }
7391
7392        excerpt_ranges.push(ExcerptRange {
7393            context: excerpt_start..excerpt_end,
7394            primary: Some(range),
7395        });
7396        range_counts.push(ranges_in_excerpt);
7397    }
7398
7399    (excerpt_ranges, range_counts)
7400}