1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  47use text::{
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50    BufferId, Edit, LineIndent, TextSummary,
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  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 MultiOrSingleBufferOffsetRange {
  83    Single(Range<usize>),
  84    Multi(Range<usize>),
  85}
  86
  87#[derive(Clone, Debug, PartialEq, Eq)]
  88pub enum Event {
  89    ExcerptsAdded {
  90        buffer: Entity<Buffer>,
  91        predecessor: ExcerptId,
  92        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  93    },
  94    ExcerptsRemoved {
  95        ids: Vec<ExcerptId>,
  96    },
  97    ExcerptsExpanded {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsEdited {
 101        ids: Vec<ExcerptId>,
 102    },
 103    DiffHunksToggled,
 104    Edited {
 105        singleton_buffer_edited: bool,
 106        edited_buffer: Option<Entity<Buffer>>,
 107    },
 108    TransactionUndone {
 109        transaction_id: TransactionId,
 110    },
 111    Reloaded,
 112    ReloadNeeded,
 113
 114    LanguageChanged(BufferId),
 115    CapabilityChanged,
 116    Reparsed(BufferId),
 117    Saved,
 118    FileHandleChanged,
 119    Closed,
 120    Discarded,
 121    DirtyChanged,
 122    DiagnosticsUpdated,
 123}
 124
 125/// A diff hunk, representing a range of consequent lines in a multibuffer.
 126#[derive(Debug, Clone, PartialEq, Eq)]
 127pub struct MultiBufferDiffHunk {
 128    /// The row range in the multibuffer where this diff hunk appears.
 129    pub row_range: Range<MultiBufferRow>,
 130    /// The buffer ID that this hunk belongs to.
 131    pub buffer_id: BufferId,
 132    /// The range of the underlying buffer that this hunk corresponds to.
 133    pub buffer_range: Range<text::Anchor>,
 134    /// The excerpt that contains the diff hunk.
 135    pub excerpt_id: ExcerptId,
 136    /// The range within the buffer's diff base that this hunk corresponds to.
 137    pub diff_base_byte_range: Range<usize>,
 138    /// Whether or not this hunk also appears in the 'secondary diff'.
 139    pub secondary_status: DiffHunkSecondaryStatus,
 140}
 141
 142impl MultiBufferDiffHunk {
 143    pub fn status(&self) -> DiffHunkStatus {
 144        let kind = if self.buffer_range.start == self.buffer_range.end {
 145            DiffHunkStatusKind::Deleted
 146        } else if self.diff_base_byte_range.is_empty() {
 147            DiffHunkStatusKind::Added
 148        } else {
 149            DiffHunkStatusKind::Modified
 150        };
 151        DiffHunkStatus {
 152            kind,
 153            secondary: self.secondary_status,
 154        }
 155    }
 156}
 157
 158#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 159pub struct PathKey {
 160    namespace: &'static str,
 161    path: Arc<Path>,
 162}
 163
 164impl PathKey {
 165    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 166        Self { namespace, path }
 167    }
 168
 169    pub fn path(&self) -> &Arc<Path> {
 170        &self.path
 171    }
 172}
 173
 174pub type MultiBufferPoint = Point;
 175type ExcerptOffset = TypedOffset<Excerpt>;
 176type ExcerptPoint = TypedPoint<Excerpt>;
 177
 178#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 179#[serde(transparent)]
 180pub struct MultiBufferRow(pub u32);
 181
 182impl MultiBufferRow {
 183    pub const MIN: Self = Self(0);
 184    pub const MAX: Self = Self(u32::MAX);
 185}
 186
 187impl std::ops::Add<usize> for MultiBufferRow {
 188    type Output = Self;
 189
 190    fn add(self, rhs: usize) -> Self::Output {
 191        MultiBufferRow(self.0 + rhs as u32)
 192    }
 193}
 194
 195#[derive(Clone)]
 196struct History {
 197    next_transaction_id: TransactionId,
 198    undo_stack: Vec<Transaction>,
 199    redo_stack: Vec<Transaction>,
 200    transaction_depth: usize,
 201    group_interval: Duration,
 202}
 203
 204#[derive(Clone)]
 205struct Transaction {
 206    id: TransactionId,
 207    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 208    first_edit_at: Instant,
 209    last_edit_at: Instant,
 210    suppress_grouping: bool,
 211}
 212
 213pub trait ToOffset: 'static + fmt::Debug {
 214    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 215}
 216
 217pub trait ToOffsetUtf16: 'static + fmt::Debug {
 218    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 219}
 220
 221pub trait ToPoint: 'static + fmt::Debug {
 222    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 223}
 224
 225pub trait ToPointUtf16: 'static + fmt::Debug {
 226    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 227}
 228
 229struct BufferState {
 230    buffer: Entity<Buffer>,
 231    last_version: clock::Global,
 232    last_non_text_state_update_count: usize,
 233    excerpts: Vec<Locator>,
 234    _subscriptions: [gpui::Subscription; 2],
 235}
 236
 237struct DiffState {
 238    diff: Entity<BufferDiff>,
 239    _subscription: gpui::Subscription,
 240}
 241
 242impl DiffState {
 243    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 244        DiffState {
 245            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 246                BufferDiffEvent::DiffChanged { changed_range } => {
 247                    let changed_range = if let Some(changed_range) = changed_range {
 248                        changed_range.clone()
 249                    } else if diff.read(cx).base_text().is_none() && this.all_diff_hunks_expanded {
 250                        text::Anchor::MIN..text::Anchor::MAX
 251                    } else {
 252                        return;
 253                    };
 254                    this.buffer_diff_changed(diff, changed_range, cx)
 255                }
 256                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 257            }),
 258            diff,
 259        }
 260    }
 261}
 262
 263/// The contents of a [`MultiBuffer`] at a single point in time.
 264#[derive(Clone, Default)]
 265pub struct MultiBufferSnapshot {
 266    singleton: bool,
 267    excerpts: SumTree<Excerpt>,
 268    excerpt_ids: SumTree<ExcerptIdMapping>,
 269    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 270    diff_transforms: SumTree<DiffTransform>,
 271    trailing_excerpt_update_count: usize,
 272    non_text_state_update_count: usize,
 273    edit_count: usize,
 274    is_dirty: bool,
 275    has_deleted_file: bool,
 276    has_conflict: bool,
 277    show_headers: bool,
 278}
 279
 280#[derive(Debug, Clone)]
 281enum DiffTransform {
 282    BufferContent {
 283        summary: TextSummary,
 284        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 285    },
 286    DeletedHunk {
 287        summary: TextSummary,
 288        buffer_id: BufferId,
 289        hunk_info: DiffTransformHunkInfo,
 290        base_text_byte_range: Range<usize>,
 291        has_trailing_newline: bool,
 292    },
 293}
 294
 295#[derive(Clone, Copy, Debug)]
 296struct DiffTransformHunkInfo {
 297    excerpt_id: ExcerptId,
 298    hunk_start_anchor: text::Anchor,
 299    hunk_secondary_status: DiffHunkSecondaryStatus,
 300}
 301
 302impl Eq for DiffTransformHunkInfo {}
 303
 304impl PartialEq for DiffTransformHunkInfo {
 305    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 306        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 307    }
 308}
 309
 310impl std::hash::Hash for DiffTransformHunkInfo {
 311    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 312        self.excerpt_id.hash(state);
 313        self.hunk_start_anchor.hash(state);
 314    }
 315}
 316
 317#[derive(Clone)]
 318pub struct ExcerptInfo {
 319    pub id: ExcerptId,
 320    pub buffer: BufferSnapshot,
 321    pub buffer_id: BufferId,
 322    pub range: ExcerptRange<text::Anchor>,
 323    pub end_row: MultiBufferRow,
 324}
 325
 326impl std::fmt::Debug for ExcerptInfo {
 327    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 328        f.debug_struct(type_name::<Self>())
 329            .field("id", &self.id)
 330            .field("buffer_id", &self.buffer_id)
 331            .field("path", &self.buffer.file().map(|f| f.path()))
 332            .field("range", &self.range)
 333            .finish()
 334    }
 335}
 336
 337/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 338#[derive(Debug)]
 339pub struct ExcerptBoundary {
 340    pub prev: Option<ExcerptInfo>,
 341    pub next: Option<ExcerptInfo>,
 342    /// The row in the `MultiBuffer` where the boundary is located
 343    pub row: MultiBufferRow,
 344}
 345
 346impl ExcerptBoundary {
 347    pub fn starts_new_buffer(&self) -> bool {
 348        match (self.prev.as_ref(), self.next.as_ref()) {
 349            (None, _) => true,
 350            (Some(_), None) => false,
 351            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 352        }
 353    }
 354}
 355
 356#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 357pub struct RowInfo {
 358    pub buffer_id: Option<BufferId>,
 359    pub buffer_row: Option<u32>,
 360    pub multibuffer_row: Option<MultiBufferRow>,
 361    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 362}
 363
 364/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 365#[derive(Clone)]
 366struct Excerpt {
 367    /// The unique identifier for this excerpt
 368    id: ExcerptId,
 369    /// The location of the excerpt in the [`MultiBuffer`]
 370    locator: Locator,
 371    /// The buffer being excerpted
 372    buffer_id: BufferId,
 373    /// A snapshot of the buffer being excerpted
 374    buffer: BufferSnapshot,
 375    /// The range of the buffer to be shown in the excerpt
 376    range: ExcerptRange<text::Anchor>,
 377    /// The last row in the excerpted slice of the buffer
 378    max_buffer_row: BufferRow,
 379    /// A summary of the text in the excerpt
 380    text_summary: TextSummary,
 381    has_trailing_newline: bool,
 382}
 383
 384/// A public view into an `Excerpt` in a [`MultiBuffer`].
 385///
 386/// Contains methods for getting the [`Buffer`] of the excerpt,
 387/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 388#[derive(Clone)]
 389pub struct MultiBufferExcerpt<'a> {
 390    excerpt: &'a Excerpt,
 391    diff_transforms:
 392        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 393    offset: usize,
 394    excerpt_offset: ExcerptDimension<usize>,
 395    buffer_offset: usize,
 396}
 397
 398#[derive(Clone, Debug)]
 399struct ExcerptIdMapping {
 400    id: ExcerptId,
 401    locator: Locator,
 402}
 403
 404/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 405/// These ranges are relative to the buffer itself
 406#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 407pub struct ExcerptRange<T> {
 408    /// The full range of text to be shown in the excerpt.
 409    pub context: Range<T>,
 410    /// The primary range of text to be highlighted in the excerpt.
 411    /// In a multi-buffer search, this would be the text that matched the search
 412    pub primary: Option<Range<T>>,
 413}
 414
 415#[derive(Clone, Debug, Default)]
 416pub struct ExcerptSummary {
 417    excerpt_id: ExcerptId,
 418    /// The location of the last [`Excerpt`] being summarized
 419    excerpt_locator: Locator,
 420    widest_line_number: u32,
 421    text: TextSummary,
 422}
 423
 424#[derive(Debug, Clone)]
 425pub struct DiffTransformSummary {
 426    input: TextSummary,
 427    output: TextSummary,
 428}
 429
 430#[derive(Clone)]
 431pub struct MultiBufferRows<'a> {
 432    point: Point,
 433    is_empty: bool,
 434    cursor: MultiBufferCursor<'a, Point>,
 435}
 436
 437pub struct MultiBufferChunks<'a> {
 438    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 439    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 440    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 441    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 442    buffer_chunk: Option<Chunk<'a>>,
 443    range: Range<usize>,
 444    excerpt_offset_range: Range<ExcerptOffset>,
 445    excerpt_chunks: Option<ExcerptChunks<'a>>,
 446    language_aware: bool,
 447}
 448
 449pub struct ReversedMultiBufferChunks<'a> {
 450    cursor: MultiBufferCursor<'a, usize>,
 451    current_chunks: Option<rope::Chunks<'a>>,
 452    start: usize,
 453    offset: usize,
 454}
 455
 456pub struct MultiBufferBytes<'a> {
 457    range: Range<usize>,
 458    cursor: MultiBufferCursor<'a, usize>,
 459    excerpt_bytes: Option<text::Bytes<'a>>,
 460    has_trailing_newline: bool,
 461    chunk: &'a [u8],
 462}
 463
 464pub struct ReversedMultiBufferBytes<'a> {
 465    range: Range<usize>,
 466    chunks: ReversedMultiBufferChunks<'a>,
 467    chunk: &'a [u8],
 468}
 469
 470#[derive(Clone)]
 471struct MultiBufferCursor<'a, D: TextDimension> {
 472    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 473    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 474    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 475    cached_region: Option<MultiBufferRegion<'a, D>>,
 476}
 477
 478#[derive(Clone)]
 479struct MultiBufferRegion<'a, D: TextDimension> {
 480    buffer: &'a BufferSnapshot,
 481    is_main_buffer: bool,
 482    diff_hunk_status: Option<DiffHunkStatus>,
 483    excerpt: &'a Excerpt,
 484    buffer_range: Range<D>,
 485    range: Range<D>,
 486    has_trailing_newline: bool,
 487}
 488
 489struct ExcerptChunks<'a> {
 490    excerpt_id: ExcerptId,
 491    content_chunks: BufferChunks<'a>,
 492    footer_height: usize,
 493}
 494
 495#[derive(Debug)]
 496struct BufferEdit {
 497    range: Range<usize>,
 498    new_text: Arc<str>,
 499    is_insertion: bool,
 500    original_start_column: u32,
 501    excerpt_id: ExcerptId,
 502}
 503
 504#[derive(Clone, Copy, Debug, PartialEq)]
 505enum DiffChangeKind {
 506    BufferEdited,
 507    DiffUpdated { base_changed: bool },
 508    ExpandOrCollapseHunks { expand: bool },
 509}
 510
 511#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 512pub enum ExpandExcerptDirection {
 513    Up,
 514    Down,
 515    UpAndDown,
 516}
 517
 518impl ExpandExcerptDirection {
 519    pub fn should_expand_up(&self) -> bool {
 520        match self {
 521            ExpandExcerptDirection::Up => true,
 522            ExpandExcerptDirection::Down => false,
 523            ExpandExcerptDirection::UpAndDown => true,
 524        }
 525    }
 526
 527    pub fn should_expand_down(&self) -> bool {
 528        match self {
 529            ExpandExcerptDirection::Up => false,
 530            ExpandExcerptDirection::Down => true,
 531            ExpandExcerptDirection::UpAndDown => true,
 532        }
 533    }
 534}
 535
 536#[derive(Clone, Debug, PartialEq)]
 537pub struct IndentGuide {
 538    pub buffer_id: BufferId,
 539    pub start_row: MultiBufferRow,
 540    pub end_row: MultiBufferRow,
 541    pub depth: u32,
 542    pub tab_size: u32,
 543    pub settings: IndentGuideSettings,
 544}
 545
 546impl IndentGuide {
 547    pub fn indent_level(&self) -> u32 {
 548        self.depth * self.tab_size
 549    }
 550}
 551
 552impl MultiBuffer {
 553    pub fn new(capability: Capability) -> Self {
 554        Self {
 555            snapshot: RefCell::new(MultiBufferSnapshot {
 556                show_headers: true,
 557                ..MultiBufferSnapshot::default()
 558            }),
 559            buffers: RefCell::default(),
 560            diffs: HashMap::default(),
 561            all_diff_hunks_expanded: false,
 562            subscriptions: Topic::default(),
 563            singleton: false,
 564            capability,
 565            title: None,
 566            buffers_by_path: Default::default(),
 567            history: History {
 568                next_transaction_id: clock::Lamport::default(),
 569                undo_stack: Vec::new(),
 570                redo_stack: Vec::new(),
 571                transaction_depth: 0,
 572                group_interval: Duration::from_millis(300),
 573            },
 574        }
 575    }
 576
 577    pub fn without_headers(capability: Capability) -> Self {
 578        Self {
 579            snapshot: Default::default(),
 580            buffers: Default::default(),
 581            buffers_by_path: Default::default(),
 582            diffs: HashMap::default(),
 583            all_diff_hunks_expanded: false,
 584            subscriptions: Default::default(),
 585            singleton: false,
 586            capability,
 587            history: History {
 588                next_transaction_id: Default::default(),
 589                undo_stack: Default::default(),
 590                redo_stack: Default::default(),
 591                transaction_depth: 0,
 592                group_interval: Duration::from_millis(300),
 593            },
 594            title: Default::default(),
 595        }
 596    }
 597
 598    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 599        let mut buffers = HashMap::default();
 600        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 601            buffers.insert(
 602                *buffer_id,
 603                BufferState {
 604                    buffer: buffer_state.buffer.clone(),
 605                    last_version: buffer_state.last_version.clone(),
 606                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 607                    excerpts: buffer_state.excerpts.clone(),
 608                    _subscriptions: [
 609                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 610                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 611                    ],
 612                },
 613            );
 614        }
 615        let mut diff_bases = HashMap::default();
 616        for (buffer_id, diff) in self.diffs.iter() {
 617            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 618        }
 619        Self {
 620            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 621            buffers: RefCell::new(buffers),
 622            buffers_by_path: Default::default(),
 623            diffs: diff_bases,
 624            all_diff_hunks_expanded: self.all_diff_hunks_expanded,
 625            subscriptions: Default::default(),
 626            singleton: self.singleton,
 627            capability: self.capability,
 628            history: self.history.clone(),
 629            title: self.title.clone(),
 630        }
 631    }
 632
 633    pub fn with_title(mut self, title: String) -> Self {
 634        self.title = Some(title);
 635        self
 636    }
 637
 638    pub fn read_only(&self) -> bool {
 639        self.capability == Capability::ReadOnly
 640    }
 641
 642    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 643        let mut this = Self::new(buffer.read(cx).capability());
 644        this.singleton = true;
 645        this.push_excerpts(
 646            buffer,
 647            [ExcerptRange {
 648                context: text::Anchor::MIN..text::Anchor::MAX,
 649                primary: None,
 650            }],
 651            cx,
 652        );
 653        this.snapshot.borrow_mut().singleton = true;
 654        this
 655    }
 656
 657    /// Returns an up-to-date snapshot of the MultiBuffer.
 658    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 659        self.sync(cx);
 660        self.snapshot.borrow().clone()
 661    }
 662
 663    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 664        self.sync(cx);
 665        self.snapshot.borrow()
 666    }
 667
 668    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 669        if self.singleton {
 670            return Some(
 671                self.buffers
 672                    .borrow()
 673                    .values()
 674                    .next()
 675                    .unwrap()
 676                    .buffer
 677                    .clone(),
 678            );
 679        } else {
 680            None
 681        }
 682    }
 683
 684    pub fn is_singleton(&self) -> bool {
 685        self.singleton
 686    }
 687
 688    pub fn subscribe(&mut self) -> Subscription {
 689        self.subscriptions.subscribe()
 690    }
 691
 692    pub fn is_dirty(&self, cx: &App) -> bool {
 693        self.read(cx).is_dirty()
 694    }
 695
 696    pub fn has_deleted_file(&self, cx: &App) -> bool {
 697        self.read(cx).has_deleted_file()
 698    }
 699
 700    pub fn has_conflict(&self, cx: &App) -> bool {
 701        self.read(cx).has_conflict()
 702    }
 703
 704    // The `is_empty` signature doesn't match what clippy expects
 705    #[allow(clippy::len_without_is_empty)]
 706    pub fn len(&self, cx: &App) -> usize {
 707        self.read(cx).len()
 708    }
 709
 710    pub fn is_empty(&self) -> bool {
 711        self.buffers.borrow().is_empty()
 712    }
 713
 714    pub fn symbols_containing<T: ToOffset>(
 715        &self,
 716        offset: T,
 717        theme: Option<&SyntaxTheme>,
 718        cx: &App,
 719    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 720        self.read(cx).symbols_containing(offset, theme)
 721    }
 722
 723    pub fn edit<I, S, T>(
 724        &self,
 725        edits: I,
 726        autoindent_mode: Option<AutoindentMode>,
 727        cx: &mut Context<Self>,
 728    ) where
 729        I: IntoIterator<Item = (Range<S>, T)>,
 730        S: ToOffset,
 731        T: Into<Arc<str>>,
 732    {
 733        let snapshot = self.read(cx);
 734        let edits = edits
 735            .into_iter()
 736            .map(|(range, new_text)| {
 737                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 738                if range.start > range.end {
 739                    mem::swap(&mut range.start, &mut range.end);
 740                }
 741                (range, new_text.into())
 742            })
 743            .collect::<Vec<_>>();
 744
 745        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 746
 747        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 748        fn edit_internal(
 749            this: &MultiBuffer,
 750            snapshot: Ref<MultiBufferSnapshot>,
 751            edits: Vec<(Range<usize>, Arc<str>)>,
 752            mut autoindent_mode: Option<AutoindentMode>,
 753            cx: &mut Context<MultiBuffer>,
 754        ) {
 755            if this.read_only() || this.buffers.borrow().is_empty() {
 756                return;
 757            }
 758
 759            let original_start_columns = match &mut autoindent_mode {
 760                Some(AutoindentMode::Block {
 761                    original_start_columns,
 762                }) => mem::take(original_start_columns),
 763                _ => Default::default(),
 764            };
 765
 766            let (buffer_edits, edited_excerpt_ids) =
 767                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_start_columns);
 768            drop(snapshot);
 769
 770            for (buffer_id, mut edits) in buffer_edits {
 771                edits.sort_by_key(|edit| edit.range.start);
 772                this.buffers.borrow()[&buffer_id]
 773                    .buffer
 774                    .update(cx, |buffer, cx| {
 775                        let mut edits = edits.into_iter().peekable();
 776                        let mut insertions = Vec::new();
 777                        let mut original_indent_columns = Vec::new();
 778                        let mut deletions = Vec::new();
 779                        let empty_str: Arc<str> = Arc::default();
 780                        while let Some(BufferEdit {
 781                            mut range,
 782                            mut new_text,
 783                            mut is_insertion,
 784                            original_start_column: original_indent_column,
 785                            excerpt_id,
 786                        }) = edits.next()
 787                        {
 788                            while let Some(BufferEdit {
 789                                range: next_range,
 790                                is_insertion: next_is_insertion,
 791                                new_text: next_new_text,
 792                                excerpt_id: next_excerpt_id,
 793                                ..
 794                            }) = edits.peek()
 795                            {
 796                                if range.end >= next_range.start {
 797                                    range.end = cmp::max(next_range.end, range.end);
 798                                    is_insertion |= *next_is_insertion;
 799                                    if excerpt_id == *next_excerpt_id {
 800                                        new_text = format!("{new_text}{next_new_text}").into();
 801                                    }
 802                                    edits.next();
 803                                } else {
 804                                    break;
 805                                }
 806                            }
 807
 808                            if is_insertion {
 809                                original_indent_columns.push(original_indent_column);
 810                                insertions.push((
 811                                    buffer.anchor_before(range.start)
 812                                        ..buffer.anchor_before(range.end),
 813                                    new_text.clone(),
 814                                ));
 815                            } else if !range.is_empty() {
 816                                deletions.push((
 817                                    buffer.anchor_before(range.start)
 818                                        ..buffer.anchor_before(range.end),
 819                                    empty_str.clone(),
 820                                ));
 821                            }
 822                        }
 823
 824                        let deletion_autoindent_mode =
 825                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 826                                Some(AutoindentMode::Block {
 827                                    original_start_columns: Default::default(),
 828                                })
 829                            } else {
 830                                autoindent_mode.clone()
 831                            };
 832                        let insertion_autoindent_mode =
 833                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 834                                Some(AutoindentMode::Block {
 835                                    original_start_columns: original_indent_columns,
 836                                })
 837                            } else {
 838                                autoindent_mode.clone()
 839                            };
 840
 841                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 842                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 843                    })
 844            }
 845
 846            cx.emit(Event::ExcerptsEdited {
 847                ids: edited_excerpt_ids,
 848            });
 849        }
 850    }
 851
 852    fn convert_edits_to_buffer_edits(
 853        &self,
 854        edits: Vec<(Range<usize>, Arc<str>)>,
 855        snapshot: &MultiBufferSnapshot,
 856        original_start_columns: &[u32],
 857    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 858        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 859        let mut edited_excerpt_ids = Vec::new();
 860        let mut cursor = snapshot.cursor::<usize>();
 861        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 862            let original_start_column = original_start_columns.get(ix).copied().unwrap_or(0);
 863
 864            cursor.seek(&range.start);
 865            let mut start_region = cursor.region().expect("start offset out of bounds");
 866            if !start_region.is_main_buffer {
 867                cursor.next();
 868                if let Some(region) = cursor.region() {
 869                    start_region = region;
 870                } else {
 871                    continue;
 872                }
 873            }
 874
 875            if range.end < start_region.range.start {
 876                continue;
 877            }
 878
 879            if range.end > start_region.range.end {
 880                cursor.seek_forward(&range.end);
 881            }
 882            let mut end_region = cursor.region().expect("end offset out of bounds");
 883            if !end_region.is_main_buffer {
 884                cursor.prev();
 885                if let Some(region) = cursor.region() {
 886                    end_region = region;
 887                } else {
 888                    continue;
 889                }
 890            }
 891
 892            if range.start > end_region.range.end {
 893                continue;
 894            }
 895
 896            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 897            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 898            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 899                .min(start_region.buffer_range.end);
 900            let buffer_end =
 901                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 902
 903            if start_region.excerpt.id == end_region.excerpt.id {
 904                if start_region.is_main_buffer {
 905                    edited_excerpt_ids.push(start_region.excerpt.id);
 906                    buffer_edits
 907                        .entry(start_region.buffer.remote_id())
 908                        .or_default()
 909                        .push(BufferEdit {
 910                            range: buffer_start..buffer_end,
 911                            new_text,
 912                            is_insertion: true,
 913                            original_start_column,
 914                            excerpt_id: start_region.excerpt.id,
 915                        });
 916                }
 917            } else {
 918                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 919                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 920                if start_region.is_main_buffer {
 921                    edited_excerpt_ids.push(start_region.excerpt.id);
 922                    buffer_edits
 923                        .entry(start_region.buffer.remote_id())
 924                        .or_default()
 925                        .push(BufferEdit {
 926                            range: start_excerpt_range,
 927                            new_text: new_text.clone(),
 928                            is_insertion: true,
 929                            original_start_column,
 930                            excerpt_id: start_region.excerpt.id,
 931                        });
 932                }
 933                if end_region.is_main_buffer {
 934                    edited_excerpt_ids.push(end_region.excerpt.id);
 935                    buffer_edits
 936                        .entry(end_region.buffer.remote_id())
 937                        .or_default()
 938                        .push(BufferEdit {
 939                            range: end_excerpt_range,
 940                            new_text: new_text.clone(),
 941                            is_insertion: false,
 942                            original_start_column,
 943                            excerpt_id: end_region.excerpt.id,
 944                        });
 945                }
 946
 947                cursor.seek(&range.start);
 948                cursor.next_excerpt();
 949                while let Some(region) = cursor.region() {
 950                    if region.excerpt.id == end_region.excerpt.id {
 951                        break;
 952                    }
 953                    if region.is_main_buffer {
 954                        edited_excerpt_ids.push(region.excerpt.id);
 955                        buffer_edits
 956                            .entry(region.buffer.remote_id())
 957                            .or_default()
 958                            .push(BufferEdit {
 959                                range: region.buffer_range,
 960                                new_text: new_text.clone(),
 961                                is_insertion: false,
 962                                original_start_column,
 963                                excerpt_id: region.excerpt.id,
 964                            });
 965                    }
 966                    cursor.next_excerpt();
 967                }
 968            }
 969        }
 970        (buffer_edits, edited_excerpt_ids)
 971    }
 972
 973    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 974    where
 975        I: IntoIterator<Item = Range<S>>,
 976        S: ToOffset,
 977    {
 978        let snapshot = self.read(cx);
 979        let empty = Arc::<str>::from("");
 980        let edits = ranges
 981            .into_iter()
 982            .map(|range| {
 983                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 984                if range.start > range.end {
 985                    mem::swap(&mut range.start, &mut range.end);
 986                }
 987                (range, empty.clone())
 988            })
 989            .collect::<Vec<_>>();
 990
 991        return autoindent_ranges_internal(self, snapshot, edits, cx);
 992
 993        fn autoindent_ranges_internal(
 994            this: &MultiBuffer,
 995            snapshot: Ref<MultiBufferSnapshot>,
 996            edits: Vec<(Range<usize>, Arc<str>)>,
 997            cx: &mut Context<MultiBuffer>,
 998        ) {
 999            if this.read_only() || this.buffers.borrow().is_empty() {
1000                return;
1001            }
1002
1003            let (buffer_edits, edited_excerpt_ids) =
1004                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1005            drop(snapshot);
1006
1007            for (buffer_id, mut edits) in buffer_edits {
1008                edits.sort_unstable_by_key(|edit| edit.range.start);
1009
1010                let mut ranges: Vec<Range<usize>> = Vec::new();
1011                for edit in edits {
1012                    if let Some(last_range) = ranges.last_mut() {
1013                        if edit.range.start <= last_range.end {
1014                            last_range.end = last_range.end.max(edit.range.end);
1015                            continue;
1016                        }
1017                    }
1018                    ranges.push(edit.range);
1019                }
1020
1021                this.buffers.borrow()[&buffer_id]
1022                    .buffer
1023                    .update(cx, |buffer, cx| {
1024                        buffer.autoindent_ranges(ranges, cx);
1025                    })
1026            }
1027
1028            cx.emit(Event::ExcerptsEdited {
1029                ids: edited_excerpt_ids,
1030            });
1031        }
1032    }
1033
1034    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1035    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1036    // Panics if the given position is invalid.
1037    pub fn insert_empty_line(
1038        &mut self,
1039        position: impl ToPoint,
1040        space_above: bool,
1041        space_below: bool,
1042        cx: &mut Context<Self>,
1043    ) -> Point {
1044        let multibuffer_point = position.to_point(&self.read(cx));
1045        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1046        self.start_transaction(cx);
1047        let empty_line_start = buffer.update(cx, |buffer, cx| {
1048            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1049        });
1050        self.end_transaction(cx);
1051        multibuffer_point + (empty_line_start - buffer_point)
1052    }
1053
1054    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1055        self.start_transaction_at(Instant::now(), cx)
1056    }
1057
1058    pub fn start_transaction_at(
1059        &mut self,
1060        now: Instant,
1061        cx: &mut Context<Self>,
1062    ) -> Option<TransactionId> {
1063        if let Some(buffer) = self.as_singleton() {
1064            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1065        }
1066
1067        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1068            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1069        }
1070        self.history.start_transaction(now)
1071    }
1072
1073    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1074        self.end_transaction_at(Instant::now(), cx)
1075    }
1076
1077    pub fn end_transaction_at(
1078        &mut self,
1079        now: Instant,
1080        cx: &mut Context<Self>,
1081    ) -> Option<TransactionId> {
1082        if let Some(buffer) = self.as_singleton() {
1083            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1084        }
1085
1086        let mut buffer_transactions = HashMap::default();
1087        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1088            if let Some(transaction_id) =
1089                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1090            {
1091                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1092            }
1093        }
1094
1095        if self.history.end_transaction(now, buffer_transactions) {
1096            let transaction_id = self.history.group().unwrap();
1097            Some(transaction_id)
1098        } else {
1099            None
1100        }
1101    }
1102
1103    pub fn edited_ranges_for_transaction<D>(
1104        &self,
1105        transaction_id: TransactionId,
1106        cx: &App,
1107    ) -> Vec<Range<D>>
1108    where
1109        D: TextDimension + Ord + Sub<D, Output = D>,
1110    {
1111        let Some(transaction) = self.history.transaction(transaction_id) else {
1112            return Vec::new();
1113        };
1114
1115        let mut ranges = Vec::new();
1116        let snapshot = self.read(cx);
1117        let buffers = self.buffers.borrow();
1118        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1119
1120        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1121            let Some(buffer_state) = buffers.get(buffer_id) else {
1122                continue;
1123            };
1124
1125            let buffer = buffer_state.buffer.read(cx);
1126            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1127                for excerpt_id in &buffer_state.excerpts {
1128                    cursor.seek(excerpt_id, Bias::Left, &());
1129                    if let Some(excerpt) = cursor.item() {
1130                        if excerpt.locator == *excerpt_id {
1131                            let excerpt_buffer_start =
1132                                excerpt.range.context.start.summary::<D>(buffer);
1133                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1134                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1135                            if excerpt_range.contains(&range.start)
1136                                && excerpt_range.contains(&range.end)
1137                            {
1138                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1139
1140                                let mut start = excerpt_start;
1141                                start.add_assign(&(range.start - excerpt_buffer_start));
1142                                let mut end = excerpt_start;
1143                                end.add_assign(&(range.end - excerpt_buffer_start));
1144
1145                                ranges.push(start..end);
1146                                break;
1147                            }
1148                        }
1149                    }
1150                }
1151            }
1152        }
1153
1154        ranges.sort_by_key(|range| range.start);
1155        ranges
1156    }
1157
1158    pub fn merge_transactions(
1159        &mut self,
1160        transaction: TransactionId,
1161        destination: TransactionId,
1162        cx: &mut Context<Self>,
1163    ) {
1164        if let Some(buffer) = self.as_singleton() {
1165            buffer.update(cx, |buffer, _| {
1166                buffer.merge_transactions(transaction, destination)
1167            });
1168        } else if let Some(transaction) = self.history.forget(transaction) {
1169            if let Some(destination) = self.history.transaction_mut(destination) {
1170                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1171                    if let Some(destination_buffer_transaction_id) =
1172                        destination.buffer_transactions.get(&buffer_id)
1173                    {
1174                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1175                            state.buffer.update(cx, |buffer, _| {
1176                                buffer.merge_transactions(
1177                                    buffer_transaction_id,
1178                                    *destination_buffer_transaction_id,
1179                                )
1180                            });
1181                        }
1182                    } else {
1183                        destination
1184                            .buffer_transactions
1185                            .insert(buffer_id, buffer_transaction_id);
1186                    }
1187                }
1188            }
1189        }
1190    }
1191
1192    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1193        self.history.finalize_last_transaction();
1194        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1195            buffer.update(cx, |buffer, _| {
1196                buffer.finalize_last_transaction();
1197            });
1198        }
1199    }
1200
1201    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1202    where
1203        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1204    {
1205        self.history
1206            .push_transaction(buffer_transactions, Instant::now(), cx);
1207        self.history.finalize_last_transaction();
1208    }
1209
1210    pub fn group_until_transaction(
1211        &mut self,
1212        transaction_id: TransactionId,
1213        cx: &mut Context<Self>,
1214    ) {
1215        if let Some(buffer) = self.as_singleton() {
1216            buffer.update(cx, |buffer, _| {
1217                buffer.group_until_transaction(transaction_id)
1218            });
1219        } else {
1220            self.history.group_until(transaction_id);
1221        }
1222    }
1223
1224    pub fn set_active_selections(
1225        &self,
1226        selections: &[Selection<Anchor>],
1227        line_mode: bool,
1228        cursor_shape: CursorShape,
1229        cx: &mut Context<Self>,
1230    ) {
1231        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1232            Default::default();
1233        let snapshot = self.read(cx);
1234        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1235        for selection in selections {
1236            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1237            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1238
1239            cursor.seek(&Some(start_locator), Bias::Left, &());
1240            while let Some(excerpt) = cursor.item() {
1241                if excerpt.locator > *end_locator {
1242                    break;
1243                }
1244
1245                let mut start = excerpt.range.context.start;
1246                let mut end = excerpt.range.context.end;
1247                if excerpt.id == selection.start.excerpt_id {
1248                    start = selection.start.text_anchor;
1249                }
1250                if excerpt.id == selection.end.excerpt_id {
1251                    end = selection.end.text_anchor;
1252                }
1253                selections_by_buffer
1254                    .entry(excerpt.buffer_id)
1255                    .or_default()
1256                    .push(Selection {
1257                        id: selection.id,
1258                        start,
1259                        end,
1260                        reversed: selection.reversed,
1261                        goal: selection.goal,
1262                    });
1263
1264                cursor.next(&());
1265            }
1266        }
1267
1268        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1269            if !selections_by_buffer.contains_key(buffer_id) {
1270                buffer_state
1271                    .buffer
1272                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1273            }
1274        }
1275
1276        for (buffer_id, mut selections) in selections_by_buffer {
1277            self.buffers.borrow()[&buffer_id]
1278                .buffer
1279                .update(cx, |buffer, cx| {
1280                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1281                    let mut selections = selections.into_iter().peekable();
1282                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1283                        let mut selection = selections.next()?;
1284                        while let Some(next_selection) = selections.peek() {
1285                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1286                                let next_selection = selections.next().unwrap();
1287                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1288                                    selection.end = next_selection.end;
1289                                }
1290                            } else {
1291                                break;
1292                            }
1293                        }
1294                        Some(selection)
1295                    }));
1296                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1297                });
1298        }
1299    }
1300
1301    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1302        for buffer in self.buffers.borrow().values() {
1303            buffer
1304                .buffer
1305                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1306        }
1307    }
1308
1309    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1310        let mut transaction_id = None;
1311        if let Some(buffer) = self.as_singleton() {
1312            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1313        } else {
1314            while let Some(transaction) = self.history.pop_undo() {
1315                let mut undone = false;
1316                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1317                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1318                        undone |= buffer.update(cx, |buffer, cx| {
1319                            let undo_to = *buffer_transaction_id;
1320                            if let Some(entry) = buffer.peek_undo_stack() {
1321                                *buffer_transaction_id = entry.transaction_id();
1322                            }
1323                            buffer.undo_to_transaction(undo_to, cx)
1324                        });
1325                    }
1326                }
1327
1328                if undone {
1329                    transaction_id = Some(transaction.id);
1330                    break;
1331                }
1332            }
1333        }
1334
1335        if let Some(transaction_id) = transaction_id {
1336            cx.emit(Event::TransactionUndone { transaction_id });
1337        }
1338
1339        transaction_id
1340    }
1341
1342    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1343        if let Some(buffer) = self.as_singleton() {
1344            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1345        }
1346
1347        while let Some(transaction) = self.history.pop_redo() {
1348            let mut redone = false;
1349            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1350                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1351                    redone |= buffer.update(cx, |buffer, cx| {
1352                        let redo_to = *buffer_transaction_id;
1353                        if let Some(entry) = buffer.peek_redo_stack() {
1354                            *buffer_transaction_id = entry.transaction_id();
1355                        }
1356                        buffer.redo_to_transaction(redo_to, cx)
1357                    });
1358                }
1359            }
1360
1361            if redone {
1362                return Some(transaction.id);
1363            }
1364        }
1365
1366        None
1367    }
1368
1369    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1370        if let Some(buffer) = self.as_singleton() {
1371            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1372        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1373            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1374                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1375                    buffer.update(cx, |buffer, cx| {
1376                        buffer.undo_transaction(*transaction_id, cx)
1377                    });
1378                }
1379            }
1380        }
1381    }
1382
1383    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1384        if let Some(buffer) = self.as_singleton() {
1385            buffer.update(cx, |buffer, _| {
1386                buffer.forget_transaction(transaction_id);
1387            });
1388        } else if let Some(transaction) = self.history.forget(transaction_id) {
1389            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1390                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1391                    state.buffer.update(cx, |buffer, _| {
1392                        buffer.forget_transaction(buffer_transaction_id);
1393                    });
1394                }
1395            }
1396        }
1397    }
1398
1399    pub fn push_excerpts<O>(
1400        &mut self,
1401        buffer: Entity<Buffer>,
1402        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1403        cx: &mut Context<Self>,
1404    ) -> Vec<ExcerptId>
1405    where
1406        O: text::ToOffset,
1407    {
1408        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1409    }
1410
1411    pub fn push_excerpts_with_context_lines<O>(
1412        &mut self,
1413        buffer: Entity<Buffer>,
1414        ranges: Vec<Range<O>>,
1415        context_line_count: u32,
1416        cx: &mut Context<Self>,
1417    ) -> Vec<Range<Anchor>>
1418    where
1419        O: text::ToPoint + text::ToOffset,
1420    {
1421        let buffer_id = buffer.read(cx).remote_id();
1422        let buffer_snapshot = buffer.read(cx).snapshot();
1423        let (excerpt_ranges, range_counts) =
1424            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1425
1426        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1427
1428        let mut anchor_ranges = Vec::new();
1429        let mut ranges = ranges.into_iter();
1430        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1431            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1432                let start = Anchor {
1433                    buffer_id: Some(buffer_id),
1434                    excerpt_id,
1435                    text_anchor: buffer_snapshot.anchor_after(range.start),
1436                    diff_base_anchor: None,
1437                };
1438                let end = Anchor {
1439                    buffer_id: Some(buffer_id),
1440                    excerpt_id,
1441                    text_anchor: buffer_snapshot.anchor_after(range.end),
1442                    diff_base_anchor: None,
1443                };
1444                start..end
1445            }))
1446        }
1447        anchor_ranges
1448    }
1449
1450    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1451        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1452        let snapshot = self.snapshot(cx);
1453        let excerpt = snapshot.excerpt(*excerpt_id)?;
1454        Some(Anchor::in_buffer(
1455            *excerpt_id,
1456            excerpt.buffer_id,
1457            excerpt.range.context.start,
1458        ))
1459    }
1460
1461    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1462        self.buffers_by_path.keys()
1463    }
1464
1465    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1466    pub fn set_excerpts_for_path(
1467        &mut self,
1468        path: PathKey,
1469        buffer: Entity<Buffer>,
1470        ranges: Vec<Range<Point>>,
1471        context_line_count: u32,
1472        cx: &mut Context<Self>,
1473    ) -> bool {
1474        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1475
1476        let mut insert_after = self
1477            .buffers_by_path
1478            .range(..path.clone())
1479            .next_back()
1480            .map(|(_, value)| *value.last().unwrap())
1481            .unwrap_or(ExcerptId::min());
1482        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1483
1484        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1485
1486        let mut new_iter = new.into_iter().peekable();
1487        let mut existing_iter = existing.into_iter().peekable();
1488
1489        let mut new_excerpt_ids = Vec::new();
1490        let mut to_remove = Vec::new();
1491        let mut to_insert = Vec::new();
1492        let mut added_a_new_excerpt = false;
1493        let snapshot = self.snapshot(cx);
1494
1495        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1496        excerpts_cursor.next(&());
1497
1498        loop {
1499            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1500                (Some(new), Some(existing)) => (new, existing),
1501                (None, None) => break,
1502                (None, Some(_)) => {
1503                    to_remove.push(existing_iter.next().unwrap());
1504                    continue;
1505                }
1506                (Some(_), None) => {
1507                    added_a_new_excerpt = true;
1508                    to_insert.push(new_iter.next().unwrap());
1509                    continue;
1510                }
1511            };
1512            let locator = snapshot.excerpt_locator_for_id(*existing);
1513            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1514            let existing_excerpt = excerpts_cursor.item().unwrap();
1515            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1516                to_remove.push(existing_iter.next().unwrap());
1517                to_insert.push(new_iter.next().unwrap());
1518                continue;
1519            }
1520
1521            let existing_start = existing_excerpt
1522                .range
1523                .context
1524                .start
1525                .to_point(&buffer_snapshot);
1526            let existing_end = existing_excerpt
1527                .range
1528                .context
1529                .end
1530                .to_point(&buffer_snapshot);
1531
1532            if existing_end < new.context.start {
1533                to_remove.push(existing_iter.next().unwrap());
1534                continue;
1535            } else if existing_start > new.context.end {
1536                to_insert.push(new_iter.next().unwrap());
1537                continue;
1538            }
1539
1540            // maybe merge overlapping excerpts?
1541            // it's hard to distinguish between a manually expanded excerpt, and one that
1542            // got smaller because of a missing diff.
1543            if existing_start == new.context.start && existing_end == new.context.end {
1544                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1545                    insert_after,
1546                    buffer.clone(),
1547                    mem::take(&mut to_insert),
1548                    cx,
1549                ));
1550                insert_after = existing_iter.next().unwrap();
1551                new_excerpt_ids.push(insert_after);
1552                new_iter.next();
1553            } else {
1554                to_remove.push(existing_iter.next().unwrap());
1555                to_insert.push(new_iter.next().unwrap());
1556            }
1557        }
1558
1559        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1560            insert_after,
1561            buffer,
1562            to_insert,
1563            cx,
1564        ));
1565        self.remove_excerpts(to_remove, cx);
1566        if new_excerpt_ids.is_empty() {
1567            self.buffers_by_path.remove(&path);
1568        } else {
1569            self.buffers_by_path.insert(path, new_excerpt_ids);
1570        }
1571
1572        added_a_new_excerpt
1573    }
1574
1575    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1576        self.buffers_by_path.keys().cloned()
1577    }
1578
1579    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1580        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1581            self.remove_excerpts(to_remove, cx)
1582        }
1583    }
1584
1585    pub fn push_multiple_excerpts_with_context_lines(
1586        &self,
1587        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1588        context_line_count: u32,
1589        cx: &mut Context<Self>,
1590    ) -> Task<Vec<Range<Anchor>>> {
1591        use futures::StreamExt;
1592
1593        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1594
1595        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1596
1597        for (buffer, ranges) in buffers_with_ranges {
1598            let (buffer_id, buffer_snapshot) =
1599                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1600
1601            buffer_ids.push(buffer_id);
1602
1603            cx.background_spawn({
1604                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1605
1606                async move {
1607                    let (excerpt_ranges, counts) =
1608                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1609                    excerpt_ranges_tx
1610                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1611                        .await
1612                        .ok();
1613                }
1614            })
1615            .detach()
1616        }
1617
1618        cx.spawn(move |this, mut cx| async move {
1619            let mut results_by_buffer_id = HashMap::default();
1620            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1621                excerpt_ranges_rx.next().await
1622            {
1623                results_by_buffer_id
1624                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1625            }
1626
1627            let mut multi_buffer_ranges = Vec::default();
1628            'outer: for buffer_id in buffer_ids {
1629                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1630                    results_by_buffer_id.remove(&buffer_id)
1631                else {
1632                    continue;
1633                };
1634
1635                let mut ranges = ranges.into_iter();
1636                let mut range_counts = range_counts.into_iter();
1637                for excerpt_ranges in excerpt_ranges.chunks(100) {
1638                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1639                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1640                    }) {
1641                        Ok(excerpt_ids) => excerpt_ids,
1642                        Err(_) => continue 'outer,
1643                    };
1644
1645                    for (excerpt_id, range_count) in
1646                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1647                    {
1648                        for range in ranges.by_ref().take(range_count) {
1649                            let start = Anchor {
1650                                buffer_id: Some(buffer_id),
1651                                excerpt_id,
1652                                text_anchor: range.start,
1653                                diff_base_anchor: None,
1654                            };
1655                            let end = Anchor {
1656                                buffer_id: Some(buffer_id),
1657                                excerpt_id,
1658                                text_anchor: range.end,
1659                                diff_base_anchor: None,
1660                            };
1661                            multi_buffer_ranges.push(start..end);
1662                        }
1663                    }
1664                }
1665            }
1666
1667            multi_buffer_ranges
1668        })
1669    }
1670
1671    pub fn insert_excerpts_after<O>(
1672        &mut self,
1673        prev_excerpt_id: ExcerptId,
1674        buffer: Entity<Buffer>,
1675        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1676        cx: &mut Context<Self>,
1677    ) -> Vec<ExcerptId>
1678    where
1679        O: text::ToOffset,
1680    {
1681        let mut ids = Vec::new();
1682        let mut next_excerpt_id =
1683            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1684                last_entry.id.0 + 1
1685            } else {
1686                1
1687            };
1688        self.insert_excerpts_with_ids_after(
1689            prev_excerpt_id,
1690            buffer,
1691            ranges.into_iter().map(|range| {
1692                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1693                ids.push(id);
1694                (id, range)
1695            }),
1696            cx,
1697        );
1698        ids
1699    }
1700
1701    pub fn insert_excerpts_with_ids_after<O>(
1702        &mut self,
1703        prev_excerpt_id: ExcerptId,
1704        buffer: Entity<Buffer>,
1705        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1706        cx: &mut Context<Self>,
1707    ) where
1708        O: text::ToOffset,
1709    {
1710        assert_eq!(self.history.transaction_depth, 0);
1711        let mut ranges = ranges.into_iter().peekable();
1712        if ranges.peek().is_none() {
1713            return Default::default();
1714        }
1715
1716        self.sync(cx);
1717
1718        let buffer_id = buffer.read(cx).remote_id();
1719        let buffer_snapshot = buffer.read(cx).snapshot();
1720
1721        let mut buffers = self.buffers.borrow_mut();
1722        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1723            last_version: buffer_snapshot.version().clone(),
1724            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1725            excerpts: Default::default(),
1726            _subscriptions: [
1727                cx.observe(&buffer, |_, _, cx| cx.notify()),
1728                cx.subscribe(&buffer, Self::on_buffer_event),
1729            ],
1730            buffer: buffer.clone(),
1731        });
1732
1733        let mut snapshot = self.snapshot.borrow_mut();
1734
1735        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1736        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1737        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1738        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1739        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1740
1741        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1742        new_excerpts.update_last(
1743            |excerpt| {
1744                excerpt.has_trailing_newline = true;
1745            },
1746            &(),
1747        );
1748
1749        let next_locator = if let Some(excerpt) = cursor.item() {
1750            excerpt.locator.clone()
1751        } else {
1752            Locator::max()
1753        };
1754
1755        let mut excerpts = Vec::new();
1756        while let Some((id, range)) = ranges.next() {
1757            let locator = Locator::between(&prev_locator, &next_locator);
1758            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1759                buffer_state.excerpts.insert(ix, locator.clone());
1760            }
1761            let range = ExcerptRange {
1762                context: buffer_snapshot.anchor_before(&range.context.start)
1763                    ..buffer_snapshot.anchor_after(&range.context.end),
1764                primary: range.primary.map(|primary| {
1765                    buffer_snapshot.anchor_before(&primary.start)
1766                        ..buffer_snapshot.anchor_after(&primary.end)
1767                }),
1768            };
1769            excerpts.push((id, range.clone()));
1770            let excerpt = Excerpt::new(
1771                id,
1772                locator.clone(),
1773                buffer_id,
1774                buffer_snapshot.clone(),
1775                range,
1776                ranges.peek().is_some() || cursor.item().is_some(),
1777            );
1778            new_excerpts.push(excerpt, &());
1779            prev_locator = locator.clone();
1780
1781            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1782                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1783            }
1784            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1785        }
1786
1787        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1788
1789        let suffix = cursor.suffix(&());
1790        let changed_trailing_excerpt = suffix.is_empty();
1791        new_excerpts.append(suffix, &());
1792        drop(cursor);
1793        snapshot.excerpts = new_excerpts;
1794        snapshot.excerpt_ids = new_excerpt_ids;
1795        if changed_trailing_excerpt {
1796            snapshot.trailing_excerpt_update_count += 1;
1797        }
1798
1799        self.sync_diff_transforms(
1800            &mut snapshot,
1801            vec![Edit {
1802                old: edit_start..edit_start,
1803                new: edit_start..edit_end,
1804            }],
1805            DiffChangeKind::BufferEdited,
1806        );
1807        cx.emit(Event::Edited {
1808            singleton_buffer_edited: false,
1809            edited_buffer: None,
1810        });
1811        cx.emit(Event::ExcerptsAdded {
1812            buffer,
1813            predecessor: prev_excerpt_id,
1814            excerpts,
1815        });
1816        cx.notify();
1817    }
1818
1819    pub fn clear(&mut self, cx: &mut Context<Self>) {
1820        self.sync(cx);
1821        let ids = self.excerpt_ids();
1822        self.buffers.borrow_mut().clear();
1823        let mut snapshot = self.snapshot.borrow_mut();
1824        let start = ExcerptOffset::new(0);
1825        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1826        snapshot.excerpts = Default::default();
1827        snapshot.trailing_excerpt_update_count += 1;
1828        snapshot.is_dirty = false;
1829        snapshot.has_deleted_file = false;
1830        snapshot.has_conflict = false;
1831
1832        self.sync_diff_transforms(
1833            &mut snapshot,
1834            vec![Edit {
1835                old: start..prev_len,
1836                new: start..start,
1837            }],
1838            DiffChangeKind::BufferEdited,
1839        );
1840        cx.emit(Event::Edited {
1841            singleton_buffer_edited: false,
1842            edited_buffer: None,
1843        });
1844        cx.emit(Event::ExcerptsRemoved { ids });
1845        cx.notify();
1846    }
1847
1848    pub fn excerpts_for_buffer(
1849        &self,
1850        buffer_id: BufferId,
1851        cx: &App,
1852    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1853        let mut excerpts = Vec::new();
1854        let snapshot = self.read(cx);
1855        let buffers = self.buffers.borrow();
1856        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1857        for locator in buffers
1858            .get(&buffer_id)
1859            .map(|state| &state.excerpts)
1860            .into_iter()
1861            .flatten()
1862        {
1863            cursor.seek_forward(&Some(locator), Bias::Left, &());
1864            if let Some(excerpt) = cursor.item() {
1865                if excerpt.locator == *locator {
1866                    excerpts.push((excerpt.id, excerpt.range.clone()));
1867                }
1868            }
1869        }
1870
1871        excerpts
1872    }
1873
1874    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1875        let snapshot = self.read(cx);
1876        let buffers = self.buffers.borrow();
1877        let mut excerpts = snapshot
1878            .excerpts
1879            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1880        let mut diff_transforms = snapshot
1881            .diff_transforms
1882            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1883        diff_transforms.next(&());
1884        let locators = buffers
1885            .get(&buffer_id)
1886            .into_iter()
1887            .flat_map(|state| &state.excerpts);
1888        let mut result = Vec::new();
1889        for locator in locators {
1890            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1891            if let Some(excerpt) = excerpts.item() {
1892                if excerpt.locator == *locator {
1893                    let excerpt_start = excerpts.start().1.clone();
1894                    let excerpt_end =
1895                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1896
1897                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1898                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1899                    let start = diff_transforms.start().1 .0 + overshoot;
1900
1901                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1902                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1903                    let end = diff_transforms.start().1 .0 + overshoot;
1904
1905                    result.push(start..end)
1906                }
1907            }
1908        }
1909        result
1910    }
1911
1912    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1913        self.snapshot
1914            .borrow()
1915            .excerpts
1916            .iter()
1917            .map(|entry| entry.buffer_id)
1918            .collect()
1919    }
1920
1921    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1922        self.snapshot
1923            .borrow()
1924            .excerpts
1925            .iter()
1926            .map(|entry| entry.id)
1927            .collect()
1928    }
1929
1930    pub fn excerpt_containing(
1931        &self,
1932        position: impl ToOffset,
1933        cx: &App,
1934    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1935        let snapshot = self.read(cx);
1936        let offset = position.to_offset(&snapshot);
1937
1938        let mut cursor = snapshot.cursor::<usize>();
1939        cursor.seek(&offset);
1940        cursor
1941            .excerpt()
1942            .or_else(|| snapshot.excerpts.last())
1943            .map(|excerpt| {
1944                (
1945                    excerpt.id,
1946                    self.buffers
1947                        .borrow()
1948                        .get(&excerpt.buffer_id)
1949                        .unwrap()
1950                        .buffer
1951                        .clone(),
1952                    excerpt.range.context.clone(),
1953                )
1954            })
1955    }
1956
1957    // If point is at the end of the buffer, the last excerpt is returned
1958    pub fn point_to_buffer_offset<T: ToOffset>(
1959        &self,
1960        point: T,
1961        cx: &App,
1962    ) -> Option<(Entity<Buffer>, usize)> {
1963        let snapshot = self.read(cx);
1964        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1965        Some((
1966            self.buffers
1967                .borrow()
1968                .get(&buffer.remote_id())?
1969                .buffer
1970                .clone(),
1971            offset,
1972        ))
1973    }
1974
1975    // If point is at the end of the buffer, the last excerpt is returned
1976    pub fn point_to_buffer_point<T: ToPoint>(
1977        &self,
1978        point: T,
1979        cx: &App,
1980    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1981        let snapshot = self.read(cx);
1982        let point = point.to_point(&snapshot);
1983        let mut cursor = snapshot.cursor::<Point>();
1984        cursor.seek(&point);
1985
1986        cursor.region().and_then(|region| {
1987            if !region.is_main_buffer {
1988                return None;
1989            }
1990
1991            let overshoot = point - region.range.start;
1992            let buffer_point = region.buffer_range.start + overshoot;
1993            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
1994                .buffer
1995                .clone();
1996            Some((buffer, buffer_point, region.excerpt.id))
1997        })
1998    }
1999
2000    pub fn buffer_point_to_anchor(
2001        &self,
2002        buffer: &Entity<Buffer>,
2003        point: Point,
2004        cx: &App,
2005    ) -> Option<Anchor> {
2006        let mut found = None;
2007        let snapshot = buffer.read(cx).snapshot();
2008        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2009            let start = range.context.start.to_point(&snapshot);
2010            let end = range.context.end.to_point(&snapshot);
2011            if start <= point && point < end {
2012                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2013                break;
2014            }
2015            if point < start {
2016                found = Some((start, excerpt_id));
2017            }
2018            if point > end {
2019                found = Some((end, excerpt_id));
2020            }
2021        }
2022
2023        found.map(|(point, excerpt_id)| {
2024            let text_anchor = snapshot.anchor_after(point);
2025            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2026        })
2027    }
2028
2029    pub fn remove_excerpts(
2030        &mut self,
2031        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2032        cx: &mut Context<Self>,
2033    ) {
2034        self.sync(cx);
2035        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2036        if ids.is_empty() {
2037            return;
2038        }
2039
2040        let mut buffers = self.buffers.borrow_mut();
2041        let mut snapshot = self.snapshot.borrow_mut();
2042        let mut new_excerpts = SumTree::default();
2043        let mut cursor = snapshot
2044            .excerpts
2045            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2046        let mut edits = Vec::new();
2047        let mut excerpt_ids = ids.iter().copied().peekable();
2048
2049        while let Some(excerpt_id) = excerpt_ids.next() {
2050            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2051            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2052            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2053
2054            if let Some(mut excerpt) = cursor.item() {
2055                if excerpt.id != excerpt_id {
2056                    continue;
2057                }
2058                let mut old_start = cursor.start().1;
2059
2060                // Skip over the removed excerpt.
2061                'remove_excerpts: loop {
2062                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2063                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2064                        if buffer_state.excerpts.is_empty() {
2065                            buffers.remove(&excerpt.buffer_id);
2066                        }
2067                    }
2068                    cursor.next(&());
2069
2070                    // Skip over any subsequent excerpts that are also removed.
2071                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2072                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2073                        if let Some(next_excerpt) = cursor.item() {
2074                            if next_excerpt.locator == *next_locator {
2075                                excerpt_ids.next();
2076                                excerpt = next_excerpt;
2077                                continue 'remove_excerpts;
2078                            }
2079                        }
2080                    }
2081
2082                    break;
2083                }
2084
2085                // When removing the last excerpt, remove the trailing newline from
2086                // the previous excerpt.
2087                if cursor.item().is_none() && old_start.value > 0 {
2088                    old_start.value -= 1;
2089                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2090                }
2091
2092                // Push an edit for the removal of this run of excerpts.
2093                let old_end = cursor.start().1;
2094                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2095                edits.push(Edit {
2096                    old: old_start..old_end,
2097                    new: new_start..new_start,
2098                });
2099            }
2100        }
2101        let suffix = cursor.suffix(&());
2102        let changed_trailing_excerpt = suffix.is_empty();
2103        new_excerpts.append(suffix, &());
2104        drop(cursor);
2105        snapshot.excerpts = new_excerpts;
2106
2107        if changed_trailing_excerpt {
2108            snapshot.trailing_excerpt_update_count += 1;
2109        }
2110
2111        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2112        cx.emit(Event::Edited {
2113            singleton_buffer_edited: false,
2114            edited_buffer: None,
2115        });
2116        cx.emit(Event::ExcerptsRemoved { ids });
2117        cx.notify();
2118    }
2119
2120    pub fn wait_for_anchors<'a>(
2121        &self,
2122        anchors: impl 'a + Iterator<Item = Anchor>,
2123        cx: &mut Context<Self>,
2124    ) -> impl 'static + Future<Output = Result<()>> {
2125        let borrow = self.buffers.borrow();
2126        let mut error = None;
2127        let mut futures = Vec::new();
2128        for anchor in anchors {
2129            if let Some(buffer_id) = anchor.buffer_id {
2130                if let Some(buffer) = borrow.get(&buffer_id) {
2131                    buffer.buffer.update(cx, |buffer, _| {
2132                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2133                    });
2134                } else {
2135                    error = Some(anyhow!(
2136                        "buffer {buffer_id} is not part of this multi-buffer"
2137                    ));
2138                    break;
2139                }
2140            }
2141        }
2142        async move {
2143            if let Some(error) = error {
2144                Err(error)?;
2145            }
2146            for future in futures {
2147                future.await?;
2148            }
2149            Ok(())
2150        }
2151    }
2152
2153    pub fn text_anchor_for_position<T: ToOffset>(
2154        &self,
2155        position: T,
2156        cx: &App,
2157    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2158        let snapshot = self.read(cx);
2159        let anchor = snapshot.anchor_before(position);
2160        let buffer = self
2161            .buffers
2162            .borrow()
2163            .get(&anchor.buffer_id?)?
2164            .buffer
2165            .clone();
2166        Some((buffer, anchor.text_anchor))
2167    }
2168
2169    fn on_buffer_event(
2170        &mut self,
2171        buffer: Entity<Buffer>,
2172        event: &language::BufferEvent,
2173        cx: &mut Context<Self>,
2174    ) {
2175        cx.emit(match event {
2176            language::BufferEvent::Edited => Event::Edited {
2177                singleton_buffer_edited: true,
2178                edited_buffer: Some(buffer.clone()),
2179            },
2180            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2181            language::BufferEvent::Saved => Event::Saved,
2182            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2183            language::BufferEvent::Reloaded => Event::Reloaded,
2184            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2185            language::BufferEvent::LanguageChanged => {
2186                Event::LanguageChanged(buffer.read(cx).remote_id())
2187            }
2188            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2189            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2190            language::BufferEvent::Closed => Event::Closed,
2191            language::BufferEvent::Discarded => Event::Discarded,
2192            language::BufferEvent::CapabilityChanged => {
2193                self.capability = buffer.read(cx).capability();
2194                Event::CapabilityChanged
2195            }
2196            language::BufferEvent::Operation { .. } => return,
2197        });
2198    }
2199
2200    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2201        self.sync(cx);
2202        let mut snapshot = self.snapshot.borrow_mut();
2203        let diff = diff.read(cx);
2204        let buffer_id = diff.buffer_id;
2205        let diff = diff.snapshot(cx);
2206        snapshot.diffs.insert(buffer_id, diff);
2207    }
2208
2209    fn buffer_diff_changed(
2210        &mut self,
2211        diff: Entity<BufferDiff>,
2212        range: Range<text::Anchor>,
2213        cx: &mut Context<Self>,
2214    ) {
2215        self.sync(cx);
2216
2217        let diff = diff.read(cx);
2218        let buffer_id = diff.buffer_id;
2219        let buffers = self.buffers.borrow();
2220        let Some(buffer_state) = buffers.get(&buffer_id) else {
2221            return;
2222        };
2223
2224        let buffer = buffer_state.buffer.read(cx);
2225        let diff_change_range = range.to_offset(buffer);
2226
2227        let mut new_diff = diff.snapshot(cx);
2228        if new_diff.base_text().is_none() && self.all_diff_hunks_expanded {
2229            let secondary_diff_insertion = new_diff
2230                .secondary_diff()
2231                .map_or(true, |secondary_diff| secondary_diff.base_text().is_none());
2232            new_diff = BufferDiff::build_with_single_insertion(
2233                secondary_diff_insertion,
2234                buffer.snapshot(),
2235                cx,
2236            );
2237        }
2238
2239        let mut snapshot = self.snapshot.borrow_mut();
2240        let base_text_changed = snapshot
2241            .diffs
2242            .get(&buffer_id)
2243            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2244
2245        snapshot.diffs.insert(buffer_id, new_diff);
2246
2247        let mut excerpt_edits = Vec::new();
2248        for locator in &buffer_state.excerpts {
2249            let mut cursor = snapshot
2250                .excerpts
2251                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2252            cursor.seek_forward(&Some(locator), Bias::Left, &());
2253            if let Some(excerpt) = cursor.item() {
2254                if excerpt.locator == *locator {
2255                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2256                    if diff_change_range.end < excerpt_buffer_range.start
2257                        || diff_change_range.start > excerpt_buffer_range.end
2258                    {
2259                        continue;
2260                    }
2261                    let excerpt_start = cursor.start().1;
2262                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2263                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2264                        diff_change_range
2265                            .start
2266                            .saturating_sub(excerpt_buffer_range.start),
2267                    );
2268                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2269                        diff_change_range
2270                            .end
2271                            .saturating_sub(excerpt_buffer_range.start),
2272                    );
2273                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2274                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2275                    excerpt_edits.push(Edit {
2276                        old: edit_start..edit_end,
2277                        new: edit_start..edit_end,
2278                    });
2279                }
2280            }
2281        }
2282
2283        self.sync_diff_transforms(
2284            &mut snapshot,
2285            excerpt_edits,
2286            DiffChangeKind::DiffUpdated {
2287                base_changed: base_text_changed,
2288            },
2289        );
2290        cx.emit(Event::Edited {
2291            singleton_buffer_edited: false,
2292            edited_buffer: None,
2293        });
2294    }
2295
2296    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2297        self.buffers
2298            .borrow()
2299            .values()
2300            .map(|state| state.buffer.clone())
2301            .collect()
2302    }
2303
2304    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2305        self.buffers
2306            .borrow()
2307            .get(&buffer_id)
2308            .map(|state| state.buffer.clone())
2309    }
2310
2311    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2312        self.point_to_buffer_offset(point, cx)
2313            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2314    }
2315
2316    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2317        let mut language = None;
2318        let mut file = None;
2319        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2320            let buffer = buffer.read(cx);
2321            language = buffer.language_at(offset);
2322            file = buffer.file();
2323        }
2324        language_settings(language.map(|l| l.name()), file, cx)
2325    }
2326
2327    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2328        self.buffers
2329            .borrow()
2330            .values()
2331            .for_each(|state| f(&state.buffer))
2332    }
2333
2334    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2335        if let Some(title) = self.title.as_ref() {
2336            return title.into();
2337        }
2338
2339        if let Some(buffer) = self.as_singleton() {
2340            if let Some(file) = buffer.read(cx).file() {
2341                return file.file_name(cx).to_string_lossy();
2342            }
2343        }
2344
2345        "untitled".into()
2346    }
2347
2348    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2349        self.title = Some(title);
2350        cx.notify();
2351    }
2352
2353    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2354    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2355        for buffer_state in self.buffers.borrow().values() {
2356            buffer_state
2357                .buffer
2358                .update(cx, |buffer, _cx| buffer.refresh_preview());
2359        }
2360    }
2361
2362    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2363    pub fn preserve_preview(&self, cx: &App) -> bool {
2364        self.buffers
2365            .borrow()
2366            .values()
2367            .all(|state| state.buffer.read(cx).preserve_preview())
2368    }
2369
2370    #[cfg(any(test, feature = "test-support"))]
2371    pub fn is_parsing(&self, cx: &App) -> bool {
2372        self.as_singleton().unwrap().read(cx).is_parsing()
2373    }
2374
2375    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2376        let buffer_id = diff.read(cx).buffer_id;
2377        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2378        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2379    }
2380
2381    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2382        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2383    }
2384
2385    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2386        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2387    }
2388
2389    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2390        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2391    }
2392
2393    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2394        self.all_diff_hunks_expanded = true;
2395        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2396    }
2397
2398    pub fn all_diff_hunks_expanded(&self) -> bool {
2399        self.all_diff_hunks_expanded
2400    }
2401
2402    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2403        self.read(cx)
2404            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2405            .nth(1)
2406            .is_some()
2407    }
2408
2409    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2410        let snapshot = self.read(cx);
2411        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2412        let offset_range = range.to_offset(&snapshot);
2413        cursor.seek(&offset_range.start, Bias::Right, &());
2414        while let Some(item) = cursor.item() {
2415            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2416                break;
2417            }
2418            if item.hunk_info().is_some() {
2419                return true;
2420            }
2421            cursor.next(&());
2422        }
2423        false
2424    }
2425
2426    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2427        let snapshot = self.read(cx);
2428        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2429        for range in ranges {
2430            let range = range.to_point(&snapshot);
2431            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2432            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2433            let start = start.saturating_sub(1);
2434            let end = snapshot.len().min(end + 1);
2435            cursor.seek(&start, Bias::Right, &());
2436            while let Some(item) = cursor.item() {
2437                if *cursor.start() >= end {
2438                    break;
2439                }
2440                if item.hunk_info().is_some() {
2441                    return true;
2442                }
2443                cursor.next(&());
2444            }
2445        }
2446        false
2447    }
2448
2449    pub fn expand_or_collapse_diff_hunks_inner(
2450        &mut self,
2451        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2452        expand: bool,
2453        cx: &mut Context<Self>,
2454    ) {
2455        if self.all_diff_hunks_expanded && !expand {
2456            return;
2457        }
2458        self.sync(cx);
2459        let mut snapshot = self.snapshot.borrow_mut();
2460        let mut excerpt_edits = Vec::new();
2461        for (range, end_excerpt_id) in ranges {
2462            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2463                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2464                    continue;
2465                }
2466                let start = Anchor::in_buffer(
2467                    diff_hunk.excerpt_id,
2468                    diff_hunk.buffer_id,
2469                    diff_hunk.buffer_range.start,
2470                );
2471                let end = Anchor::in_buffer(
2472                    diff_hunk.excerpt_id,
2473                    diff_hunk.buffer_id,
2474                    diff_hunk.buffer_range.end,
2475                );
2476                let start = snapshot.excerpt_offset_for_anchor(&start);
2477                let end = snapshot.excerpt_offset_for_anchor(&end);
2478                excerpt_edits.push(text::Edit {
2479                    old: start..end,
2480                    new: start..end,
2481                });
2482            }
2483        }
2484
2485        self.sync_diff_transforms(
2486            &mut snapshot,
2487            excerpt_edits,
2488            DiffChangeKind::ExpandOrCollapseHunks { expand },
2489        );
2490        cx.emit(Event::DiffHunksToggled);
2491        cx.emit(Event::Edited {
2492            singleton_buffer_edited: false,
2493            edited_buffer: None,
2494        });
2495    }
2496
2497    pub fn expand_or_collapse_diff_hunks(
2498        &mut self,
2499        ranges: Vec<Range<Anchor>>,
2500        expand: bool,
2501        cx: &mut Context<Self>,
2502    ) {
2503        let snapshot = self.snapshot.borrow().clone();
2504        let ranges = ranges.iter().map(move |range| {
2505            let end_excerpt_id = range.end.excerpt_id;
2506            let range = range.to_point(&snapshot);
2507            let mut peek_end = range.end;
2508            if range.end.row < snapshot.max_row().0 {
2509                peek_end = Point::new(range.end.row + 1, 0);
2510            };
2511            (range.start..peek_end, end_excerpt_id)
2512        });
2513        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2514    }
2515
2516    pub fn resize_excerpt(
2517        &mut self,
2518        id: ExcerptId,
2519        range: Range<text::Anchor>,
2520        cx: &mut Context<Self>,
2521    ) {
2522        self.sync(cx);
2523
2524        let mut snapshot = self.snapshot.borrow_mut();
2525        let locator = snapshot.excerpt_locator_for_id(id);
2526        let mut new_excerpts = SumTree::default();
2527        let mut cursor = snapshot
2528            .excerpts
2529            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2530        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2531
2532        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2533        new_excerpts.append(prefix, &());
2534
2535        let mut excerpt = cursor.item().unwrap().clone();
2536        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2537
2538        excerpt.range.context.start = range.start;
2539        excerpt.range.context.end = range.end;
2540        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2541
2542        excerpt.text_summary = excerpt
2543            .buffer
2544            .text_summary_for_range(excerpt.range.context.clone());
2545
2546        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2547        let old_start_offset = cursor.start().1;
2548        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2549        let edit = Edit {
2550            old: old_start_offset..old_start_offset + old_text_len,
2551            new: new_start_offset..new_start_offset + new_text_len,
2552        };
2553
2554        if let Some(last_edit) = edits.last_mut() {
2555            if last_edit.old.end == edit.old.start {
2556                last_edit.old.end = edit.old.end;
2557                last_edit.new.end = edit.new.end;
2558            } else {
2559                edits.push(edit);
2560            }
2561        } else {
2562            edits.push(edit);
2563        }
2564
2565        new_excerpts.push(excerpt, &());
2566
2567        cursor.next(&());
2568
2569        new_excerpts.append(cursor.suffix(&()), &());
2570
2571        drop(cursor);
2572        snapshot.excerpts = new_excerpts;
2573
2574        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2575        cx.emit(Event::Edited {
2576            singleton_buffer_edited: false,
2577            edited_buffer: None,
2578        });
2579        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2580        cx.notify();
2581    }
2582
2583    pub fn expand_excerpts(
2584        &mut self,
2585        ids: impl IntoIterator<Item = ExcerptId>,
2586        line_count: u32,
2587        direction: ExpandExcerptDirection,
2588        cx: &mut Context<Self>,
2589    ) {
2590        if line_count == 0 {
2591            return;
2592        }
2593        self.sync(cx);
2594        let mut snapshot = self.snapshot.borrow_mut();
2595
2596        let ids = ids.into_iter().collect::<Vec<_>>();
2597        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2598        let mut new_excerpts = SumTree::default();
2599        let mut cursor = snapshot
2600            .excerpts
2601            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2602        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2603
2604        for locator in &locators {
2605            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2606            new_excerpts.append(prefix, &());
2607
2608            let mut excerpt = cursor.item().unwrap().clone();
2609            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2610
2611            let up_line_count = if direction.should_expand_up() {
2612                line_count
2613            } else {
2614                0
2615            };
2616
2617            let start_row = excerpt
2618                .range
2619                .context
2620                .start
2621                .to_point(&excerpt.buffer)
2622                .row
2623                .saturating_sub(up_line_count);
2624            let start_point = Point::new(start_row, 0);
2625            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2626
2627            let down_line_count = if direction.should_expand_down() {
2628                line_count
2629            } else {
2630                0
2631            };
2632
2633            let mut end_point = excerpt.buffer.clip_point(
2634                excerpt.range.context.end.to_point(&excerpt.buffer)
2635                    + Point::new(down_line_count, 0),
2636                Bias::Left,
2637            );
2638            end_point.column = excerpt.buffer.line_len(end_point.row);
2639            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2640            excerpt.max_buffer_row = end_point.row;
2641
2642            excerpt.text_summary = excerpt
2643                .buffer
2644                .text_summary_for_range(excerpt.range.context.clone());
2645
2646            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2647            let old_start_offset = cursor.start().1;
2648            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2649            let edit = Edit {
2650                old: old_start_offset..old_start_offset + old_text_len,
2651                new: new_start_offset..new_start_offset + new_text_len,
2652            };
2653
2654            if let Some(last_edit) = edits.last_mut() {
2655                if last_edit.old.end == edit.old.start {
2656                    last_edit.old.end = edit.old.end;
2657                    last_edit.new.end = edit.new.end;
2658                } else {
2659                    edits.push(edit);
2660                }
2661            } else {
2662                edits.push(edit);
2663            }
2664
2665            new_excerpts.push(excerpt, &());
2666
2667            cursor.next(&());
2668        }
2669
2670        new_excerpts.append(cursor.suffix(&()), &());
2671
2672        drop(cursor);
2673        snapshot.excerpts = new_excerpts;
2674
2675        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2676        cx.emit(Event::Edited {
2677            singleton_buffer_edited: false,
2678            edited_buffer: None,
2679        });
2680        cx.emit(Event::ExcerptsExpanded { ids });
2681        cx.notify();
2682    }
2683
2684    fn sync(&self, cx: &App) {
2685        let mut snapshot = self.snapshot.borrow_mut();
2686        let mut excerpts_to_edit = Vec::new();
2687        let mut non_text_state_updated = false;
2688        let mut is_dirty = false;
2689        let mut has_deleted_file = false;
2690        let mut has_conflict = false;
2691        let mut edited = false;
2692        let mut buffers = self.buffers.borrow_mut();
2693        for buffer_state in buffers.values_mut() {
2694            let buffer = buffer_state.buffer.read(cx);
2695            let version = buffer.version();
2696            let non_text_state_update_count = buffer.non_text_state_update_count();
2697
2698            let buffer_edited = version.changed_since(&buffer_state.last_version);
2699            let buffer_non_text_state_updated =
2700                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2701            if buffer_edited || buffer_non_text_state_updated {
2702                buffer_state.last_version = version;
2703                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2704                excerpts_to_edit.extend(
2705                    buffer_state
2706                        .excerpts
2707                        .iter()
2708                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2709                );
2710            }
2711
2712            edited |= buffer_edited;
2713            non_text_state_updated |= buffer_non_text_state_updated;
2714            is_dirty |= buffer.is_dirty();
2715            has_deleted_file |= buffer
2716                .file()
2717                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2718            has_conflict |= buffer.has_conflict();
2719        }
2720        if edited {
2721            snapshot.edit_count += 1;
2722        }
2723        if non_text_state_updated {
2724            snapshot.non_text_state_update_count += 1;
2725        }
2726        snapshot.is_dirty = is_dirty;
2727        snapshot.has_deleted_file = has_deleted_file;
2728        snapshot.has_conflict = has_conflict;
2729
2730        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2731
2732        let mut edits = Vec::new();
2733        let mut new_excerpts = SumTree::default();
2734        let mut cursor = snapshot
2735            .excerpts
2736            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2737
2738        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2739            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2740            let old_excerpt = cursor.item().unwrap();
2741            let buffer = buffer.read(cx);
2742            let buffer_id = buffer.remote_id();
2743
2744            let mut new_excerpt;
2745            if buffer_edited {
2746                edits.extend(
2747                    buffer
2748                        .edits_since_in_range::<usize>(
2749                            old_excerpt.buffer.version(),
2750                            old_excerpt.range.context.clone(),
2751                        )
2752                        .map(|edit| {
2753                            let excerpt_old_start = cursor.start().1;
2754                            let excerpt_new_start =
2755                                ExcerptOffset::new(new_excerpts.summary().text.len);
2756                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2757                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2758                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2759                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2760                            Edit {
2761                                old: old_start..old_end,
2762                                new: new_start..new_end,
2763                            }
2764                        }),
2765                );
2766
2767                new_excerpt = Excerpt::new(
2768                    old_excerpt.id,
2769                    locator.clone(),
2770                    buffer_id,
2771                    buffer.snapshot(),
2772                    old_excerpt.range.clone(),
2773                    old_excerpt.has_trailing_newline,
2774                );
2775            } else {
2776                new_excerpt = old_excerpt.clone();
2777                new_excerpt.buffer = buffer.snapshot();
2778            }
2779
2780            new_excerpts.push(new_excerpt, &());
2781            cursor.next(&());
2782        }
2783        new_excerpts.append(cursor.suffix(&()), &());
2784
2785        drop(cursor);
2786        snapshot.excerpts = new_excerpts;
2787
2788        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2789    }
2790
2791    fn sync_diff_transforms(
2792        &self,
2793        snapshot: &mut MultiBufferSnapshot,
2794        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2795        change_kind: DiffChangeKind,
2796    ) {
2797        if excerpt_edits.is_empty() {
2798            return;
2799        }
2800
2801        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2802        let mut old_diff_transforms = snapshot
2803            .diff_transforms
2804            .cursor::<(ExcerptOffset, usize)>(&());
2805        let mut new_diff_transforms = SumTree::default();
2806        let mut old_expanded_hunks = HashSet::default();
2807        let mut output_edits = Vec::new();
2808        let mut output_delta = 0_isize;
2809        let mut at_transform_boundary = true;
2810        let mut end_of_current_insert = None;
2811
2812        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2813        while let Some(edit) = excerpt_edits.next() {
2814            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2815            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2816                excerpts.prev(&());
2817            }
2818
2819            // Keep any transforms that are before the edit.
2820            if at_transform_boundary {
2821                at_transform_boundary = false;
2822                let transforms_before_edit =
2823                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2824                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2825                if let Some(transform) = old_diff_transforms.item() {
2826                    if old_diff_transforms.end(&()).0 == edit.old.start
2827                        && old_diff_transforms.start().0 < edit.old.start
2828                    {
2829                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2830                        old_diff_transforms.next(&());
2831                    }
2832                }
2833            }
2834
2835            // Compute the start of the edit in output coordinates.
2836            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2837            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2838            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2839
2840            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2841                &edit,
2842                &mut excerpts,
2843                &mut old_diff_transforms,
2844                &mut new_diff_transforms,
2845                &mut end_of_current_insert,
2846                &mut old_expanded_hunks,
2847                &snapshot,
2848                change_kind,
2849            );
2850
2851            // Compute the end of the edit in output coordinates.
2852            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2853            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2854            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2855            let edit_new_end =
2856                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2857            let output_edit = Edit {
2858                old: edit_old_start..edit_old_end,
2859                new: edit_new_start..edit_new_end,
2860            };
2861
2862            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2863            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2864            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2865                output_edits.push(output_edit);
2866            }
2867
2868            // If this is the last edit that intersects the current diff transform,
2869            // then recreate the content up to the end of this transform, to prepare
2870            // for reusing additional slices of the old transforms.
2871            if excerpt_edits.peek().map_or(true, |next_edit| {
2872                next_edit.old.start >= old_diff_transforms.end(&()).0
2873            }) {
2874                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2875                    && match old_diff_transforms.item() {
2876                        Some(DiffTransform::BufferContent {
2877                            inserted_hunk_info: Some(hunk),
2878                            ..
2879                        }) => excerpts.item().is_some_and(|excerpt| {
2880                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2881                        }),
2882                        _ => true,
2883                    };
2884
2885                let mut excerpt_offset = edit.new.end;
2886                if !keep_next_old_transform {
2887                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2888                    old_diff_transforms.next(&());
2889                }
2890
2891                old_expanded_hunks.clear();
2892                self.push_buffer_content_transform(
2893                    &snapshot,
2894                    &mut new_diff_transforms,
2895                    excerpt_offset,
2896                    end_of_current_insert,
2897                );
2898                at_transform_boundary = true;
2899            }
2900        }
2901
2902        // Keep any transforms that are after the last edit.
2903        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2904
2905        // Ensure there's always at least one buffer content transform.
2906        if new_diff_transforms.is_empty() {
2907            new_diff_transforms.push(
2908                DiffTransform::BufferContent {
2909                    summary: Default::default(),
2910                    inserted_hunk_info: None,
2911                },
2912                &(),
2913            );
2914        }
2915
2916        self.subscriptions.publish(output_edits);
2917        drop(old_diff_transforms);
2918        drop(excerpts);
2919        snapshot.diff_transforms = new_diff_transforms;
2920        snapshot.edit_count += 1;
2921
2922        #[cfg(any(test, feature = "test-support"))]
2923        snapshot.check_invariants();
2924    }
2925
2926    #[allow(clippy::too_many_arguments)]
2927    fn recompute_diff_transforms_for_edit(
2928        &self,
2929        edit: &Edit<TypedOffset<Excerpt>>,
2930        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2931        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2932        new_diff_transforms: &mut SumTree<DiffTransform>,
2933        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2934        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2935        snapshot: &MultiBufferSnapshot,
2936        change_kind: DiffChangeKind,
2937    ) -> bool {
2938        log::trace!(
2939            "recomputing diff transform for edit {:?} => {:?}",
2940            edit.old.start.value..edit.old.end.value,
2941            edit.new.start.value..edit.new.end.value
2942        );
2943
2944        // Record which hunks were previously expanded.
2945        while let Some(item) = old_diff_transforms.item() {
2946            if let Some(hunk_info) = item.hunk_info() {
2947                log::trace!(
2948                    "previously expanded hunk at {}",
2949                    old_diff_transforms.start().0
2950                );
2951                old_expanded_hunks.insert(hunk_info);
2952            }
2953            if old_diff_transforms.end(&()).0 > edit.old.end {
2954                break;
2955            }
2956            old_diff_transforms.next(&());
2957        }
2958
2959        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2960        if old_expanded_hunks.is_empty()
2961            && change_kind == DiffChangeKind::BufferEdited
2962            && !self.all_diff_hunks_expanded
2963        {
2964            return false;
2965        }
2966
2967        // Visit each excerpt that intersects the edit.
2968        let mut did_expand_hunks = false;
2969        while let Some(excerpt) = excerpts.item() {
2970            // Recompute the expanded hunks in the portion of the excerpt that
2971            // intersects the edit.
2972            if let Some((diff, base_text)) = snapshot
2973                .diffs
2974                .get(&excerpt.buffer_id)
2975                .and_then(|diff| Some((diff, diff.base_text()?)))
2976            {
2977                let buffer = &excerpt.buffer;
2978                let excerpt_start = *excerpts.start();
2979                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2980                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2981                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2982                let edit_buffer_start =
2983                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2984                let edit_buffer_end =
2985                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2986                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2987                let edit_anchor_range =
2988                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2989
2990                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2991                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2992
2993                    let hunk_info = DiffTransformHunkInfo {
2994                        excerpt_id: excerpt.id,
2995                        hunk_start_anchor: hunk.buffer_range.start,
2996                        hunk_secondary_status: hunk.secondary_status,
2997                    };
2998                    if hunk_buffer_range.start < excerpt_buffer_start {
2999                        log::trace!("skipping hunk that starts before excerpt");
3000                        continue;
3001                    }
3002
3003                    let hunk_excerpt_start = excerpt_start
3004                        + ExcerptOffset::new(
3005                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3006                        );
3007                    let hunk_excerpt_end = excerpt_end.min(
3008                        excerpt_start
3009                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3010                    );
3011
3012                    self.push_buffer_content_transform(
3013                        snapshot,
3014                        new_diff_transforms,
3015                        hunk_excerpt_start,
3016                        *end_of_current_insert,
3017                    );
3018
3019                    // For every existing hunk, determine if it was previously expanded
3020                    // and if it should currently be expanded.
3021                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3022                    let should_expand_hunk = match &change_kind {
3023                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3024                            self.all_diff_hunks_expanded || was_previously_expanded
3025                        }
3026                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3027                            let intersects = hunk_buffer_range.is_empty()
3028                                || hunk_buffer_range.end > edit_buffer_start;
3029                            if *expand {
3030                                intersects
3031                                    || was_previously_expanded
3032                                    || self.all_diff_hunks_expanded
3033                            } else {
3034                                !intersects
3035                                    && (was_previously_expanded || self.all_diff_hunks_expanded)
3036                            }
3037                        }
3038                        _ => was_previously_expanded || self.all_diff_hunks_expanded,
3039                    };
3040
3041                    if should_expand_hunk {
3042                        did_expand_hunks = true;
3043                        log::trace!(
3044                            "expanding hunk {:?}, excerpt:{:?}",
3045                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3046                            excerpt.id
3047                        );
3048
3049                        if !hunk.diff_base_byte_range.is_empty()
3050                            && hunk_buffer_range.start >= edit_buffer_start
3051                            && hunk_buffer_range.start <= excerpt_buffer_end
3052                        {
3053                            let mut text_cursor =
3054                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3055                            let mut base_text_summary =
3056                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3057
3058                            let mut has_trailing_newline = false;
3059                            if base_text_summary.last_line_chars > 0 {
3060                                base_text_summary += TextSummary::newline();
3061                                has_trailing_newline = true;
3062                            }
3063
3064                            new_diff_transforms.push(
3065                                DiffTransform::DeletedHunk {
3066                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3067                                    summary: base_text_summary,
3068                                    buffer_id: excerpt.buffer_id,
3069                                    hunk_info,
3070                                    has_trailing_newline,
3071                                },
3072                                &(),
3073                            );
3074                        }
3075
3076                        if !hunk_buffer_range.is_empty() {
3077                            *end_of_current_insert =
3078                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3079                        }
3080                    }
3081                }
3082            }
3083
3084            if excerpts.end(&()) <= edit.new.end {
3085                excerpts.next(&());
3086            } else {
3087                break;
3088            }
3089        }
3090
3091        did_expand_hunks || !old_expanded_hunks.is_empty()
3092    }
3093
3094    fn append_diff_transforms(
3095        &self,
3096        new_transforms: &mut SumTree<DiffTransform>,
3097        subtree: SumTree<DiffTransform>,
3098    ) {
3099        if let Some(DiffTransform::BufferContent {
3100            inserted_hunk_info,
3101            summary,
3102        }) = subtree.first()
3103        {
3104            if self.extend_last_buffer_content_transform(
3105                new_transforms,
3106                *inserted_hunk_info,
3107                *summary,
3108            ) {
3109                let mut cursor = subtree.cursor::<()>(&());
3110                cursor.next(&());
3111                cursor.next(&());
3112                new_transforms.append(cursor.suffix(&()), &());
3113                return;
3114            }
3115        }
3116        new_transforms.append(subtree, &());
3117    }
3118
3119    fn push_diff_transform(
3120        &self,
3121        new_transforms: &mut SumTree<DiffTransform>,
3122        transform: DiffTransform,
3123    ) {
3124        if let DiffTransform::BufferContent {
3125            inserted_hunk_info: inserted_hunk_anchor,
3126            summary,
3127        } = transform
3128        {
3129            if self.extend_last_buffer_content_transform(
3130                new_transforms,
3131                inserted_hunk_anchor,
3132                summary,
3133            ) {
3134                return;
3135            }
3136        }
3137        new_transforms.push(transform, &());
3138    }
3139
3140    fn push_buffer_content_transform(
3141        &self,
3142        old_snapshot: &MultiBufferSnapshot,
3143        new_transforms: &mut SumTree<DiffTransform>,
3144        end_offset: ExcerptOffset,
3145        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3146    ) {
3147        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3148            (end_offset.min(insertion_end_offset), Some(hunk_info))
3149        });
3150        let unchanged_region = [(end_offset, None)];
3151
3152        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3153        {
3154            let start_offset = new_transforms.summary().excerpt_len();
3155            if end_offset <= start_offset {
3156                continue;
3157            }
3158            let summary_to_add = old_snapshot
3159                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3160
3161            if !self.extend_last_buffer_content_transform(
3162                new_transforms,
3163                inserted_hunk_info,
3164                summary_to_add,
3165            ) {
3166                new_transforms.push(
3167                    DiffTransform::BufferContent {
3168                        summary: summary_to_add,
3169                        inserted_hunk_info,
3170                    },
3171                    &(),
3172                )
3173            }
3174        }
3175    }
3176
3177    fn extend_last_buffer_content_transform(
3178        &self,
3179        new_transforms: &mut SumTree<DiffTransform>,
3180        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3181        summary_to_add: TextSummary,
3182    ) -> bool {
3183        let mut did_extend = false;
3184        new_transforms.update_last(
3185            |last_transform| {
3186                if let DiffTransform::BufferContent {
3187                    summary,
3188                    inserted_hunk_info: inserted_hunk_anchor,
3189                } = last_transform
3190                {
3191                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3192                        *summary += summary_to_add;
3193                        did_extend = true;
3194                    }
3195                }
3196            },
3197            &(),
3198        );
3199        did_extend
3200    }
3201}
3202
3203#[cfg(any(test, feature = "test-support"))]
3204impl MultiBuffer {
3205    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3206        let buffer = cx.new(|cx| Buffer::local(text, cx));
3207        cx.new(|cx| Self::singleton(buffer, cx))
3208    }
3209
3210    pub fn build_multi<const COUNT: usize>(
3211        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3212        cx: &mut gpui::App,
3213    ) -> Entity<Self> {
3214        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3215        for (text, ranges) in excerpts {
3216            let buffer = cx.new(|cx| Buffer::local(text, cx));
3217            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3218                context: range,
3219                primary: None,
3220            });
3221            multi.update(cx, |multi, cx| {
3222                multi.push_excerpts(buffer, excerpt_ranges, cx)
3223            });
3224        }
3225
3226        multi
3227    }
3228
3229    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3230        cx.new(|cx| Self::singleton(buffer, cx))
3231    }
3232
3233    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3234        cx.new(|cx| {
3235            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3236            let mutation_count = rng.gen_range(1..=5);
3237            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3238            multibuffer
3239        })
3240    }
3241
3242    pub fn randomly_edit(
3243        &mut self,
3244        rng: &mut impl rand::Rng,
3245        edit_count: usize,
3246        cx: &mut Context<Self>,
3247    ) {
3248        use util::RandomCharIter;
3249
3250        let snapshot = self.read(cx);
3251        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3252        let mut last_end = None;
3253        for _ in 0..edit_count {
3254            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3255                break;
3256            }
3257
3258            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3259            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3260            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3261            last_end = Some(end);
3262
3263            let mut range = start..end;
3264            if rng.gen_bool(0.2) {
3265                mem::swap(&mut range.start, &mut range.end);
3266            }
3267
3268            let new_text_len = rng.gen_range(0..10);
3269            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3270
3271            edits.push((range, new_text.into()));
3272        }
3273        log::info!("mutating multi-buffer with {:?}", edits);
3274        drop(snapshot);
3275
3276        self.edit(edits, None, cx);
3277    }
3278
3279    pub fn randomly_edit_excerpts(
3280        &mut self,
3281        rng: &mut impl rand::Rng,
3282        mutation_count: usize,
3283        cx: &mut Context<Self>,
3284    ) {
3285        use rand::prelude::*;
3286        use std::env;
3287        use util::RandomCharIter;
3288
3289        let max_excerpts = env::var("MAX_EXCERPTS")
3290            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3291            .unwrap_or(5);
3292
3293        let mut buffers = Vec::new();
3294        for _ in 0..mutation_count {
3295            if rng.gen_bool(0.05) {
3296                log::info!("Clearing multi-buffer");
3297                self.clear(cx);
3298                continue;
3299            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3300                let ids = self.excerpt_ids();
3301                let mut excerpts = HashSet::default();
3302                for _ in 0..rng.gen_range(0..ids.len()) {
3303                    excerpts.extend(ids.choose(rng).copied());
3304                }
3305
3306                let line_count = rng.gen_range(0..5);
3307
3308                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3309
3310                self.expand_excerpts(
3311                    excerpts.iter().cloned(),
3312                    line_count,
3313                    ExpandExcerptDirection::UpAndDown,
3314                    cx,
3315                );
3316                continue;
3317            }
3318
3319            let excerpt_ids = self.excerpt_ids();
3320            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3321                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3322                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3323                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3324                    let buffer = buffers.last().unwrap().read(cx);
3325                    log::info!(
3326                        "Creating new buffer {} with text: {:?}",
3327                        buffer.remote_id(),
3328                        buffer.text()
3329                    );
3330                    buffers.last().unwrap().clone()
3331                } else {
3332                    self.buffers
3333                        .borrow()
3334                        .values()
3335                        .choose(rng)
3336                        .unwrap()
3337                        .buffer
3338                        .clone()
3339                };
3340
3341                let buffer = buffer_handle.read(cx);
3342                let buffer_text = buffer.text();
3343                let ranges = (0..rng.gen_range(0..5))
3344                    .map(|_| {
3345                        let end_ix =
3346                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3347                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3348                        ExcerptRange {
3349                            context: start_ix..end_ix,
3350                            primary: None,
3351                        }
3352                    })
3353                    .collect::<Vec<_>>();
3354                log::info!(
3355                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3356                    buffer_handle.read(cx).remote_id(),
3357                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3358                    ranges
3359                        .iter()
3360                        .map(|r| &buffer_text[r.context.clone()])
3361                        .collect::<Vec<_>>()
3362                );
3363
3364                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3365                log::info!("Inserted with ids: {:?}", excerpt_id);
3366            } else {
3367                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3368                let mut excerpts_to_remove = excerpt_ids
3369                    .choose_multiple(rng, remove_count)
3370                    .cloned()
3371                    .collect::<Vec<_>>();
3372                let snapshot = self.snapshot.borrow();
3373                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3374                drop(snapshot);
3375                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3376                self.remove_excerpts(excerpts_to_remove, cx);
3377            }
3378        }
3379    }
3380
3381    pub fn randomly_mutate(
3382        &mut self,
3383        rng: &mut impl rand::Rng,
3384        mutation_count: usize,
3385        cx: &mut Context<Self>,
3386    ) {
3387        use rand::prelude::*;
3388
3389        if rng.gen_bool(0.7) || self.singleton {
3390            let buffer = self
3391                .buffers
3392                .borrow()
3393                .values()
3394                .choose(rng)
3395                .map(|state| state.buffer.clone());
3396
3397            if let Some(buffer) = buffer {
3398                buffer.update(cx, |buffer, cx| {
3399                    if rng.gen() {
3400                        buffer.randomly_edit(rng, mutation_count, cx);
3401                    } else {
3402                        buffer.randomly_undo_redo(rng, cx);
3403                    }
3404                });
3405            } else {
3406                self.randomly_edit(rng, mutation_count, cx);
3407            }
3408        } else {
3409            self.randomly_edit_excerpts(rng, mutation_count, cx);
3410        }
3411
3412        self.check_invariants(cx);
3413    }
3414
3415    fn check_invariants(&self, cx: &App) {
3416        self.read(cx).check_invariants();
3417    }
3418}
3419
3420impl EventEmitter<Event> for MultiBuffer {}
3421
3422impl MultiBufferSnapshot {
3423    pub fn text(&self) -> String {
3424        self.chunks(0..self.len(), false)
3425            .map(|chunk| chunk.text)
3426            .collect()
3427    }
3428
3429    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3430        self.reversed_chunks_in_range(0..position.to_offset(self))
3431            .flat_map(|c| c.chars().rev())
3432    }
3433
3434    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3435        let mut cursor = self.cursor::<usize>();
3436        cursor.seek(&range.end);
3437        let current_chunks = cursor.region().as_ref().map(|region| {
3438            let start_overshoot = range.start.saturating_sub(region.range.start);
3439            let end_overshoot = range.end - region.range.start;
3440            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3441            let start = region.buffer_range.start + start_overshoot;
3442            region.buffer.reversed_chunks_in_range(start..end)
3443        });
3444        ReversedMultiBufferChunks {
3445            cursor,
3446            current_chunks,
3447            start: range.start,
3448            offset: range.end,
3449        }
3450    }
3451
3452    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3453        let offset = position.to_offset(self);
3454        self.text_for_range(offset..self.len())
3455            .flat_map(|chunk| chunk.chars())
3456    }
3457
3458    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3459        self.chunks(range, false).map(|chunk| chunk.text)
3460    }
3461
3462    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3463        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3464            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3465    }
3466
3467    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3468    where
3469        T: ToOffset,
3470    {
3471        let position = position.to_offset(self);
3472        position == self.clip_offset(position, Bias::Left)
3473            && self
3474                .bytes_in_range(position..self.len())
3475                .flatten()
3476                .copied()
3477                .take(needle.len())
3478                .eq(needle.bytes())
3479    }
3480
3481    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3482        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3483    }
3484
3485    pub fn diff_hunks_in_range<T: ToPoint>(
3486        &self,
3487        range: Range<T>,
3488    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3489        let query_range = range.start.to_point(self)..range.end.to_point(self);
3490        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3491            let diff = self.diffs.get(&buffer.remote_id())?;
3492            let buffer_start = buffer.anchor_before(buffer_range.start);
3493            let buffer_end = buffer.anchor_after(buffer_range.end);
3494            Some(
3495                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3496                    .map(|hunk| {
3497                        (
3498                            Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
3499                            hunk,
3500                        )
3501                    }),
3502            )
3503        })
3504        .filter_map(move |(range, hunk, excerpt)| {
3505            if range.start != range.end
3506                && range.end == query_range.start
3507                && !hunk.row_range.is_empty()
3508            {
3509                return None;
3510            }
3511            let end_row = if range.end.column == 0 {
3512                range.end.row
3513            } else {
3514                range.end.row + 1
3515            };
3516            Some(MultiBufferDiffHunk {
3517                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3518                buffer_id: excerpt.buffer_id,
3519                excerpt_id: excerpt.id,
3520                buffer_range: hunk.buffer_range.clone(),
3521                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3522                secondary_status: hunk.secondary_status,
3523            })
3524        })
3525    }
3526
3527    pub fn excerpt_ids_for_range<T: ToOffset>(
3528        &self,
3529        range: Range<T>,
3530    ) -> impl Iterator<Item = ExcerptId> + '_ {
3531        let range = range.start.to_offset(self)..range.end.to_offset(self);
3532        let mut cursor = self.cursor::<usize>();
3533        cursor.seek(&range.start);
3534        std::iter::from_fn(move || {
3535            let region = cursor.region()?;
3536            if region.range.start >= range.end {
3537                return None;
3538            }
3539            cursor.next_excerpt();
3540            Some(region.excerpt.id)
3541        })
3542    }
3543
3544    pub fn buffer_ids_for_range<T: ToOffset>(
3545        &self,
3546        range: Range<T>,
3547    ) -> impl Iterator<Item = BufferId> + '_ {
3548        let range = range.start.to_offset(self)..range.end.to_offset(self);
3549        let mut cursor = self.cursor::<usize>();
3550        cursor.seek(&range.start);
3551        std::iter::from_fn(move || {
3552            let region = cursor.region()?;
3553            if region.range.start >= range.end {
3554                return None;
3555            }
3556            cursor.next_excerpt();
3557            Some(region.excerpt.buffer_id)
3558        })
3559    }
3560
3561    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3562        &self,
3563        ranges: impl Iterator<Item = Range<T>>,
3564    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3565        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3566    }
3567
3568    pub fn range_to_buffer_ranges<T: ToOffset>(
3569        &self,
3570        range: Range<T>,
3571    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3572        let start = range.start.to_offset(&self);
3573        let end = range.end.to_offset(&self);
3574
3575        let mut cursor = self.cursor::<usize>();
3576        cursor.seek(&start);
3577
3578        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3579        while let Some(region) = cursor.region() {
3580            if region.range.start > end {
3581                break;
3582            }
3583            if region.is_main_buffer {
3584                let start_overshoot = start.saturating_sub(region.range.start);
3585                let end_overshoot = end.saturating_sub(region.range.start);
3586                let start = region
3587                    .buffer_range
3588                    .end
3589                    .min(region.buffer_range.start + start_overshoot);
3590                let end = region
3591                    .buffer_range
3592                    .end
3593                    .min(region.buffer_range.start + end_overshoot);
3594                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3595                    *excerpt_id == region.excerpt.id && prev_range.end == start
3596                }) {
3597                    prev.1.end = end;
3598                } else {
3599                    result.push((region.buffer, start..end, region.excerpt.id));
3600                }
3601            }
3602            cursor.next();
3603        }
3604        result
3605    }
3606
3607    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3608        &self,
3609        range: Range<T>,
3610    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3611        let start = range.start.to_offset(&self);
3612        let end = range.end.to_offset(&self);
3613
3614        let mut cursor = self.cursor::<usize>();
3615        cursor.seek(&start);
3616
3617        std::iter::from_fn(move || {
3618            let region = cursor.region()?;
3619            if region.range.start > end {
3620                return None;
3621            }
3622            let start_overshoot = start.saturating_sub(region.range.start);
3623            let end_overshoot = end.saturating_sub(region.range.start);
3624            let start = region
3625                .buffer_range
3626                .end
3627                .min(region.buffer_range.start + start_overshoot);
3628            let end = region
3629                .buffer_range
3630                .end
3631                .min(region.buffer_range.start + end_overshoot);
3632
3633            let region_excerpt_id = region.excerpt.id;
3634            let deleted_hunk_anchor = if region.is_main_buffer {
3635                None
3636            } else {
3637                Some(self.anchor_before(region.range.start))
3638            };
3639            let result = (
3640                region.buffer,
3641                start..end,
3642                region_excerpt_id,
3643                deleted_hunk_anchor,
3644            );
3645            cursor.next();
3646            Some(result)
3647        })
3648    }
3649
3650    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3651    /// coordinates.
3652    ///
3653    /// The given callback will be called for every excerpt intersecting the given range. It will
3654    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3655    /// The callback should return an iterator of metadata items from that buffer, each paired
3656    /// with a buffer range.
3657    ///
3658    /// The returned iterator yields each of these metadata items, paired with its range in
3659    /// multi-buffer coordinates.
3660    fn lift_buffer_metadata<'a, D, M, I>(
3661        &'a self,
3662        query_range: Range<D>,
3663        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3664    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3665    where
3666        I: Iterator<Item = (Range<D>, M)> + 'a,
3667        D: TextDimension + Ord + Sub<D, Output = D>,
3668    {
3669        let max_position = D::from_text_summary(&self.text_summary());
3670        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3671        let mut cursor = self.cursor::<D>();
3672
3673        // Find the excerpt and buffer offset where the given range ends.
3674        cursor.seek(&query_range.end);
3675        let mut range_end = None;
3676        while let Some(region) = cursor.region() {
3677            if region.is_main_buffer {
3678                let mut buffer_end = region.buffer_range.start;
3679                let overshoot = if query_range.end > region.range.start {
3680                    query_range.end - region.range.start
3681                } else {
3682                    D::default()
3683                };
3684                buffer_end.add_assign(&overshoot);
3685                range_end = Some((region.excerpt.id, buffer_end));
3686                break;
3687            }
3688            cursor.next();
3689        }
3690
3691        cursor.seek(&query_range.start);
3692
3693        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3694            if region.range.start > D::zero(&()) {
3695                cursor.prev()
3696            }
3697        }
3698
3699        iter::from_fn(move || loop {
3700            let excerpt = cursor.excerpt()?;
3701
3702            // If we have already retrieved metadata for this excerpt, continue to use it.
3703            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3704                .as_mut()
3705                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3706            {
3707                Some(metadata)
3708            }
3709            // Otherwise, compute the intersection of the input range with the excerpt's range,
3710            // and retrieve the metadata for the resulting range.
3711            else {
3712                let region = cursor.region()?;
3713                let mut buffer_start;
3714                if region.is_main_buffer {
3715                    buffer_start = region.buffer_range.start;
3716                    if query_range.start > region.range.start {
3717                        let overshoot = query_range.start - region.range.start;
3718                        buffer_start.add_assign(&overshoot);
3719                    }
3720                    buffer_start = buffer_start.min(region.buffer_range.end);
3721                } else {
3722                    buffer_start = cursor.main_buffer_position()?;
3723                };
3724                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3725                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3726                    if excerpt.id == end_excerpt_id {
3727                        buffer_end = buffer_end.min(end_buffer_offset);
3728                    }
3729                }
3730
3731                if let Some(iterator) =
3732                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3733                {
3734                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3735                } else {
3736                    None
3737                }
3738            };
3739
3740            // Visit each metadata item.
3741            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3742            {
3743                // Find the multibuffer regions that contain the start and end of
3744                // the metadata item's range.
3745                if metadata_buffer_range.start > D::default() {
3746                    while let Some(region) = cursor.region() {
3747                        if region.is_main_buffer
3748                            && (region.buffer_range.end >= metadata_buffer_range.start
3749                                || cursor.is_at_end_of_excerpt())
3750                        {
3751                            break;
3752                        }
3753                        cursor.next();
3754                    }
3755                }
3756                let start_region = cursor.region()?;
3757                while let Some(region) = cursor.region() {
3758                    if region.is_main_buffer
3759                        && (region.buffer_range.end > metadata_buffer_range.end
3760                            || cursor.is_at_end_of_excerpt())
3761                    {
3762                        break;
3763                    }
3764                    cursor.next();
3765                }
3766                let end_region = cursor.region();
3767
3768                // Convert the metadata item's range into multibuffer coordinates.
3769                let mut start_position = start_region.range.start;
3770                let region_buffer_start = start_region.buffer_range.start;
3771                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3772                {
3773                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3774                    start_position = start_position.min(start_region.range.end);
3775                }
3776
3777                let mut end_position = max_position;
3778                if let Some(end_region) = &end_region {
3779                    end_position = end_region.range.start;
3780                    debug_assert!(end_region.is_main_buffer);
3781                    let region_buffer_start = end_region.buffer_range.start;
3782                    if metadata_buffer_range.end > region_buffer_start {
3783                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3784                    }
3785                    end_position = end_position.min(end_region.range.end);
3786                }
3787
3788                if start_position <= query_range.end && end_position >= query_range.start {
3789                    return Some((start_position..end_position, metadata, excerpt));
3790                }
3791            }
3792            // When there are no more metadata items for this excerpt, move to the next excerpt.
3793            else {
3794                current_excerpt_metadata.take();
3795                cursor.next_excerpt();
3796            }
3797        })
3798    }
3799
3800    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3801        let offset = position.to_offset(self);
3802
3803        // Go to the region containing the given offset.
3804        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3805        cursor.seek(&DimensionPair {
3806            key: offset,
3807            value: None,
3808        });
3809        let mut region = cursor.region()?;
3810        if region.range.start.key == offset || !region.is_main_buffer {
3811            cursor.prev();
3812            region = cursor.region()?;
3813        }
3814
3815        // Find the corresponding buffer offset.
3816        let overshoot = if region.is_main_buffer {
3817            offset - region.range.start.key
3818        } else {
3819            0
3820        };
3821        let mut max_buffer_offset = region
3822            .buffer
3823            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3824
3825        loop {
3826            let excerpt = cursor.excerpt()?;
3827            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3828            let buffer_offset = excerpt_end.min(max_buffer_offset);
3829            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3830            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3831
3832            if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3833                for hunk in diff.hunks_intersecting_range_rev(
3834                    excerpt.range.context.start..buffer_end,
3835                    &excerpt.buffer,
3836                ) {
3837                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3838                    if hunk.row_range.end >= buffer_end_row {
3839                        continue;
3840                    }
3841
3842                    let hunk_start = Point::new(hunk.row_range.start, 0);
3843                    let hunk_end = Point::new(hunk.row_range.end, 0);
3844
3845                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3846                        key: hunk_range.start,
3847                        value: None,
3848                    });
3849
3850                    let mut region = cursor.region()?;
3851                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3852                    {
3853                        cursor.prev();
3854                        region = cursor.region()?;
3855                    }
3856
3857                    let overshoot = if region.is_main_buffer {
3858                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3859                    } else {
3860                        Point::zero()
3861                    };
3862                    let start = region.range.start.value.unwrap() + overshoot;
3863
3864                    while let Some(region) = cursor.region() {
3865                        if !region.is_main_buffer
3866                            || region.buffer_range.end.value.unwrap() <= hunk_end
3867                        {
3868                            cursor.next();
3869                        } else {
3870                            break;
3871                        }
3872                    }
3873
3874                    let end = if let Some(region) = cursor.region() {
3875                        let overshoot = if region.is_main_buffer {
3876                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3877                        } else {
3878                            Point::zero()
3879                        };
3880                        region.range.start.value.unwrap() + overshoot
3881                    } else {
3882                        self.max_point()
3883                    };
3884
3885                    return Some(MultiBufferDiffHunk {
3886                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3887                        buffer_id: excerpt.buffer_id,
3888                        excerpt_id: excerpt.id,
3889                        buffer_range: hunk.buffer_range.clone(),
3890                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3891                        secondary_status: hunk.secondary_status,
3892                    });
3893                }
3894            }
3895
3896            cursor.prev_excerpt();
3897            max_buffer_offset = usize::MAX;
3898        }
3899    }
3900
3901    pub fn has_diff_hunks(&self) -> bool {
3902        self.diffs.values().any(|diff| !diff.is_empty())
3903    }
3904
3905    pub fn surrounding_word<T: ToOffset>(
3906        &self,
3907        start: T,
3908        for_completion: bool,
3909    ) -> (Range<usize>, Option<CharKind>) {
3910        let mut start = start.to_offset(self);
3911        let mut end = start;
3912        let mut next_chars = self.chars_at(start).peekable();
3913        let mut prev_chars = self.reversed_chars_at(start).peekable();
3914
3915        let classifier = self
3916            .char_classifier_at(start)
3917            .for_completion(for_completion);
3918
3919        let word_kind = cmp::max(
3920            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3921            next_chars.peek().copied().map(|c| classifier.kind(c)),
3922        );
3923
3924        for ch in prev_chars {
3925            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3926                start -= ch.len_utf8();
3927            } else {
3928                break;
3929            }
3930        }
3931
3932        for ch in next_chars {
3933            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3934                end += ch.len_utf8();
3935            } else {
3936                break;
3937            }
3938        }
3939
3940        (start..end, word_kind)
3941    }
3942
3943    pub fn is_singleton(&self) -> bool {
3944        self.singleton
3945    }
3946
3947    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3948        if self.singleton {
3949            self.excerpts
3950                .iter()
3951                .next()
3952                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3953        } else {
3954            None
3955        }
3956    }
3957
3958    pub fn len(&self) -> usize {
3959        self.diff_transforms.summary().output.len
3960    }
3961
3962    pub fn is_empty(&self) -> bool {
3963        self.excerpts.summary().text.len == 0
3964    }
3965
3966    pub fn widest_line_number(&self) -> u32 {
3967        self.excerpts.summary().widest_line_number + 1
3968    }
3969
3970    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3971        let range = range.start.to_offset(self)..range.end.to_offset(self);
3972        let mut excerpts = self.cursor::<usize>();
3973        excerpts.seek(&range.start);
3974
3975        let mut chunk;
3976        let mut has_trailing_newline;
3977        let excerpt_bytes;
3978        if let Some(region) = excerpts.region() {
3979            let mut bytes = region.buffer.bytes_in_range(
3980                region.buffer_range.start + range.start - region.range.start
3981                    ..(region.buffer_range.start + range.end - region.range.start)
3982                        .min(region.buffer_range.end),
3983            );
3984            chunk = bytes.next().unwrap_or(&[][..]);
3985            excerpt_bytes = Some(bytes);
3986            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3987            if chunk.is_empty() && has_trailing_newline {
3988                chunk = b"\n";
3989                has_trailing_newline = false;
3990            }
3991        } else {
3992            chunk = &[][..];
3993            excerpt_bytes = None;
3994            has_trailing_newline = false;
3995        };
3996
3997        MultiBufferBytes {
3998            range,
3999            cursor: excerpts,
4000            excerpt_bytes,
4001            has_trailing_newline,
4002            chunk,
4003        }
4004    }
4005
4006    pub fn reversed_bytes_in_range<T: ToOffset>(
4007        &self,
4008        range: Range<T>,
4009    ) -> ReversedMultiBufferBytes {
4010        let range = range.start.to_offset(self)..range.end.to_offset(self);
4011        let mut chunks = self.reversed_chunks_in_range(range.clone());
4012        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4013        ReversedMultiBufferBytes {
4014            range,
4015            chunks,
4016            chunk,
4017        }
4018    }
4019
4020    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4021        let mut cursor = self.cursor::<Point>();
4022        cursor.seek(&Point::new(start_row.0, 0));
4023        let mut result = MultiBufferRows {
4024            point: Point::new(0, 0),
4025            is_empty: self.excerpts.is_empty(),
4026            cursor,
4027        };
4028        result.seek(start_row);
4029        result
4030    }
4031
4032    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4033        let mut chunks = MultiBufferChunks {
4034            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4035            range: 0..0,
4036            excerpts: self.excerpts.cursor(&()),
4037            diff_transforms: self.diff_transforms.cursor(&()),
4038            diffs: &self.diffs,
4039            diff_base_chunks: None,
4040            excerpt_chunks: None,
4041            buffer_chunk: None,
4042            language_aware,
4043        };
4044        let range = range.start.to_offset(self)..range.end.to_offset(self);
4045        chunks.seek(range);
4046        chunks
4047    }
4048
4049    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4050        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4051    }
4052
4053    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4054        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4055    }
4056
4057    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4058        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4059    }
4060
4061    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4062        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4063            buffer.clip_point_utf16(Unclipped(point), bias)
4064        })
4065    }
4066
4067    pub fn offset_to_point(&self, offset: usize) -> Point {
4068        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4069    }
4070
4071    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4072        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4073    }
4074
4075    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4076        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4077    }
4078
4079    pub fn point_to_offset(&self, point: Point) -> usize {
4080        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4081    }
4082
4083    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4084        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4085    }
4086
4087    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4088        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4089    }
4090
4091    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4092        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4093    }
4094
4095    fn clip_dimension<D>(
4096        &self,
4097        position: D,
4098        bias: Bias,
4099        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4100    ) -> D
4101    where
4102        D: TextDimension + Ord + Sub<D, Output = D>,
4103    {
4104        let mut cursor = self.cursor();
4105        cursor.seek(&position);
4106        if let Some(region) = cursor.region() {
4107            if position >= region.range.end {
4108                return region.range.end;
4109            }
4110            let overshoot = position - region.range.start;
4111            let mut buffer_position = region.buffer_range.start;
4112            buffer_position.add_assign(&overshoot);
4113            let clipped_buffer_position =
4114                clip_buffer_position(&region.buffer, buffer_position, bias);
4115            let mut position = region.range.start;
4116            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4117            position
4118        } else {
4119            D::from_text_summary(&self.text_summary())
4120        }
4121    }
4122
4123    fn convert_dimension<D1, D2>(
4124        &self,
4125        key: D1,
4126        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4127    ) -> D2
4128    where
4129        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4130        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4131    {
4132        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4133        cursor.seek(&DimensionPair { key, value: None });
4134        if let Some(region) = cursor.region() {
4135            if key >= region.range.end.key {
4136                return region.range.end.value.unwrap();
4137            }
4138            let start_key = region.range.start.key;
4139            let start_value = region.range.start.value.unwrap();
4140            let buffer_start_key = region.buffer_range.start.key;
4141            let buffer_start_value = region.buffer_range.start.value.unwrap();
4142            let mut buffer_key = buffer_start_key;
4143            buffer_key.add_assign(&(key - start_key));
4144            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4145            let mut result = start_value;
4146            result.add_assign(&(buffer_value - buffer_start_value));
4147            result
4148        } else {
4149            D2::from_text_summary(&self.text_summary())
4150        }
4151    }
4152
4153    pub fn point_to_buffer_offset<T: ToOffset>(
4154        &self,
4155        point: T,
4156    ) -> Option<(&BufferSnapshot, usize)> {
4157        let offset = point.to_offset(self);
4158        let mut cursor = self.cursor::<usize>();
4159        cursor.seek(&offset);
4160        let region = cursor.region()?;
4161        let overshoot = offset - region.range.start;
4162        let buffer_offset = region.buffer_range.start + overshoot;
4163        Some((region.buffer, buffer_offset))
4164    }
4165
4166    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4167        let mut cursor = self.cursor::<Point>();
4168        cursor.seek(&point);
4169        let region = cursor.region()?;
4170        let overshoot = point - region.range.start;
4171        let buffer_offset = region.buffer_range.start + overshoot;
4172        Some((region.buffer, buffer_offset, region.is_main_buffer))
4173    }
4174
4175    pub fn suggested_indents(
4176        &self,
4177        rows: impl IntoIterator<Item = u32>,
4178        cx: &App,
4179    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4180        let mut result = BTreeMap::new();
4181
4182        let mut rows_for_excerpt = Vec::new();
4183        let mut cursor = self.cursor::<Point>();
4184        let mut rows = rows.into_iter().peekable();
4185        let mut prev_row = u32::MAX;
4186        let mut prev_language_indent_size = IndentSize::default();
4187
4188        while let Some(row) = rows.next() {
4189            cursor.seek(&Point::new(row, 0));
4190            let Some(region) = cursor.region() else {
4191                continue;
4192            };
4193
4194            // Retrieve the language and indent size once for each disjoint region being indented.
4195            let single_indent_size = if row.saturating_sub(1) == prev_row {
4196                prev_language_indent_size
4197            } else {
4198                region
4199                    .buffer
4200                    .language_indent_size_at(Point::new(row, 0), cx)
4201            };
4202            prev_language_indent_size = single_indent_size;
4203            prev_row = row;
4204
4205            let start_buffer_row = region.buffer_range.start.row;
4206            let start_multibuffer_row = region.range.start.row;
4207            let end_multibuffer_row = region.range.end.row;
4208
4209            rows_for_excerpt.push(row);
4210            while let Some(next_row) = rows.peek().copied() {
4211                if end_multibuffer_row > next_row {
4212                    rows_for_excerpt.push(next_row);
4213                    rows.next();
4214                } else {
4215                    break;
4216                }
4217            }
4218
4219            let buffer_rows = rows_for_excerpt
4220                .drain(..)
4221                .map(|row| start_buffer_row + row - start_multibuffer_row);
4222            let buffer_indents = region
4223                .buffer
4224                .suggested_indents(buffer_rows, single_indent_size);
4225            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4226                (
4227                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4228                    indent,
4229                )
4230            });
4231            result.extend(multibuffer_indents);
4232        }
4233
4234        result
4235    }
4236
4237    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4238        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4239            let mut size = buffer.indent_size_for_line(range.start.row);
4240            size.len = size
4241                .len
4242                .min(range.end.column)
4243                .saturating_sub(range.start.column);
4244            size
4245        } else {
4246            IndentSize::spaces(0)
4247        }
4248    }
4249
4250    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4251        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4252            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4253        } else {
4254            LineIndent::spaces(0)
4255        }
4256    }
4257
4258    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4259        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4260
4261        if self.settings_at(0, cx).extend_comment_on_newline {
4262            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4263                let delimiters = language_scope.line_comment_prefixes();
4264                for delimiter in delimiters {
4265                    if *self
4266                        .chars_at(Point::new(row.0, indent.len() as u32))
4267                        .take(delimiter.chars().count())
4268                        .collect::<String>()
4269                        .as_str()
4270                        == **delimiter
4271                    {
4272                        indent.push_str(&delimiter);
4273                        break;
4274                    }
4275                }
4276            }
4277        }
4278
4279        indent
4280    }
4281
4282    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4283    where
4284        T: ToOffset,
4285    {
4286        for char in self.reversed_chars_at(position) {
4287            if !char.is_whitespace() {
4288                return false;
4289            }
4290            if char == '\n' {
4291                return true;
4292            }
4293        }
4294        return true;
4295    }
4296
4297    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4298        while row.0 > 0 {
4299            row.0 -= 1;
4300            if !self.is_line_blank(row) {
4301                return Some(row);
4302            }
4303        }
4304        None
4305    }
4306
4307    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4308        if let Some((_, range)) = self.buffer_line_for_row(row) {
4309            range.end.column - range.start.column
4310        } else {
4311            0
4312        }
4313    }
4314
4315    pub fn buffer_line_for_row(
4316        &self,
4317        row: MultiBufferRow,
4318    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4319        let mut cursor = self.cursor::<Point>();
4320        let point = Point::new(row.0, 0);
4321        cursor.seek(&point);
4322        let region = cursor.region()?;
4323        let overshoot = point.min(region.range.end) - region.range.start;
4324        let buffer_point = region.buffer_range.start + overshoot;
4325        if buffer_point.row > region.buffer_range.end.row {
4326            return None;
4327        }
4328        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4329        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4330            .min(region.buffer_range.end);
4331        Some((region.buffer, line_start..line_end))
4332    }
4333
4334    pub fn max_point(&self) -> Point {
4335        self.text_summary().lines
4336    }
4337
4338    pub fn max_row(&self) -> MultiBufferRow {
4339        MultiBufferRow(self.text_summary().lines.row)
4340    }
4341
4342    pub fn text_summary(&self) -> TextSummary {
4343        self.diff_transforms.summary().output
4344    }
4345
4346    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4347    where
4348        D: TextDimension,
4349        O: ToOffset,
4350    {
4351        let range = range.start.to_offset(self)..range.end.to_offset(self);
4352        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4353        cursor.seek(&range.start, Bias::Right, &());
4354
4355        let Some(first_transform) = cursor.item() else {
4356            return D::from_text_summary(&TextSummary::default());
4357        };
4358
4359        let diff_transform_start = cursor.start().0;
4360        let diff_transform_end = cursor.end(&()).0;
4361        let diff_start = range.start;
4362        let start_overshoot = diff_start - diff_transform_start;
4363        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4364
4365        let mut result = match first_transform {
4366            DiffTransform::BufferContent { .. } => {
4367                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4368                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4369                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4370            }
4371            DiffTransform::DeletedHunk {
4372                buffer_id,
4373                base_text_byte_range,
4374                has_trailing_newline,
4375                ..
4376            } => {
4377                let buffer_start = base_text_byte_range.start + start_overshoot;
4378                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4379                let Some(base_text) = self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4380                else {
4381                    panic!("{:?} is in non-existent deleted hunk", range.start)
4382                };
4383
4384                let include_trailing_newline =
4385                    *has_trailing_newline && range.end >= diff_transform_end;
4386                if include_trailing_newline {
4387                    buffer_end -= 1;
4388                }
4389
4390                let mut summary =
4391                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4392
4393                if include_trailing_newline {
4394                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4395                }
4396
4397                summary
4398            }
4399        };
4400        if range.end < diff_transform_end {
4401            return result;
4402        }
4403
4404        cursor.next(&());
4405        result.add_assign(&D::from_text_summary(&cursor.summary(
4406            &range.end,
4407            Bias::Right,
4408            &(),
4409        )));
4410
4411        let Some(last_transform) = cursor.item() else {
4412            return result;
4413        };
4414
4415        let overshoot = range.end - cursor.start().0;
4416        let suffix = match last_transform {
4417            DiffTransform::BufferContent { .. } => {
4418                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4419                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4420            }
4421            DiffTransform::DeletedHunk {
4422                base_text_byte_range,
4423                buffer_id,
4424                has_trailing_newline,
4425                ..
4426            } => {
4427                let buffer_end = base_text_byte_range.start + overshoot;
4428                let Some(base_text) = self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4429                else {
4430                    panic!("{:?} is in non-existent deleted hunk", range.end)
4431                };
4432
4433                let mut suffix = base_text
4434                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4435                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4436                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4437                }
4438                suffix
4439            }
4440        };
4441
4442        result.add_assign(&suffix);
4443        result
4444    }
4445
4446    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4447    where
4448        D: TextDimension,
4449    {
4450        // let mut range = range.start..range.end;
4451        let mut summary = D::zero(&());
4452        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4453        cursor.seek(&range.start, Bias::Right, &());
4454        if let Some(excerpt) = cursor.item() {
4455            let mut end_before_newline = cursor.end(&());
4456            if excerpt.has_trailing_newline {
4457                end_before_newline -= ExcerptOffset::new(1);
4458            }
4459
4460            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4461            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4462            let end_in_excerpt =
4463                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4464            summary.add_assign(
4465                &excerpt
4466                    .buffer
4467                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4468            );
4469
4470            if range.end > end_before_newline {
4471                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4472            }
4473
4474            cursor.next(&());
4475        }
4476
4477        if range.end > *cursor.start() {
4478            summary.add_assign(
4479                &cursor
4480                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4481                    .0,
4482            );
4483            if let Some(excerpt) = cursor.item() {
4484                range.end = cmp::max(*cursor.start(), range.end);
4485
4486                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4487                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4488                summary.add_assign(
4489                    &excerpt
4490                        .buffer
4491                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4492                );
4493            }
4494        }
4495
4496        summary
4497    }
4498
4499    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4500    where
4501        D: TextDimension + Ord + Sub<D, Output = D>,
4502    {
4503        self.summaries_for_anchors([anchor])[0]
4504    }
4505
4506    fn resolve_summary_for_anchor<D>(
4507        &self,
4508        anchor: &Anchor,
4509        excerpt_position: D,
4510        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4511    ) -> D
4512    where
4513        D: TextDimension + Ord + Sub<D, Output = D>,
4514    {
4515        loop {
4516            let transform_end_position = diff_transforms.end(&()).0 .0;
4517            let at_transform_end =
4518                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4519            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4520                diff_transforms.next(&());
4521                continue;
4522            }
4523
4524            let mut position = diff_transforms.start().1 .0;
4525            match diff_transforms.item() {
4526                Some(DiffTransform::DeletedHunk {
4527                    buffer_id,
4528                    base_text_byte_range,
4529                    ..
4530                }) => {
4531                    let mut in_deleted_hunk = false;
4532                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4533                        if let Some(base_text) =
4534                            self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4535                        {
4536                            if base_text.can_resolve(&diff_base_anchor) {
4537                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4538                                if base_text_offset >= base_text_byte_range.start
4539                                    && base_text_offset <= base_text_byte_range.end
4540                                {
4541                                    let position_in_hunk = base_text
4542                                        .text_summary_for_range::<D, _>(
4543                                            base_text_byte_range.start..base_text_offset,
4544                                        );
4545                                    position.add_assign(&position_in_hunk);
4546                                    in_deleted_hunk = true;
4547                                } else if at_transform_end {
4548                                    diff_transforms.next(&());
4549                                    continue;
4550                                }
4551                            }
4552                        }
4553                    }
4554                    if !in_deleted_hunk {
4555                        position = diff_transforms.end(&()).1 .0;
4556                    }
4557                }
4558                _ => {
4559                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4560                        diff_transforms.next(&());
4561                        continue;
4562                    }
4563                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4564                    position.add_assign(&overshoot);
4565                }
4566            }
4567
4568            return position;
4569        }
4570    }
4571
4572    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4573        let mut cursor = self
4574            .excerpts
4575            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4576        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4577
4578        cursor.seek(&Some(locator), Bias::Left, &());
4579        if cursor.item().is_none() {
4580            cursor.next(&());
4581        }
4582
4583        let mut position = cursor.start().1;
4584        if let Some(excerpt) = cursor.item() {
4585            if excerpt.id == anchor.excerpt_id {
4586                let excerpt_buffer_start = excerpt
4587                    .buffer
4588                    .offset_for_anchor(&excerpt.range.context.start);
4589                let excerpt_buffer_end =
4590                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4591                let buffer_position = cmp::min(
4592                    excerpt_buffer_end,
4593                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4594                );
4595                if buffer_position > excerpt_buffer_start {
4596                    position.value += buffer_position - excerpt_buffer_start;
4597                }
4598            }
4599        }
4600        position
4601    }
4602
4603    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4604    where
4605        D: TextDimension + Ord + Sub<D, Output = D>,
4606        I: 'a + IntoIterator<Item = &'a Anchor>,
4607    {
4608        let mut anchors = anchors.into_iter().peekable();
4609        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4610        let mut diff_transforms_cursor = self
4611            .diff_transforms
4612            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4613        diff_transforms_cursor.next(&());
4614
4615        let mut summaries = Vec::new();
4616        while let Some(anchor) = anchors.peek() {
4617            let excerpt_id = anchor.excerpt_id;
4618            let excerpt_anchors = iter::from_fn(|| {
4619                let anchor = anchors.peek()?;
4620                if anchor.excerpt_id == excerpt_id {
4621                    Some(anchors.next().unwrap())
4622                } else {
4623                    None
4624                }
4625            });
4626
4627            let locator = self.excerpt_locator_for_id(excerpt_id);
4628            cursor.seek_forward(locator, Bias::Left, &());
4629            if cursor.item().is_none() {
4630                cursor.next(&());
4631            }
4632
4633            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4634            if let Some(excerpt) = cursor.item() {
4635                if excerpt.id != excerpt_id {
4636                    let position = self.resolve_summary_for_anchor(
4637                        &Anchor::min(),
4638                        excerpt_start_position,
4639                        &mut diff_transforms_cursor,
4640                    );
4641                    summaries.extend(excerpt_anchors.map(|_| position));
4642                    continue;
4643                }
4644                let excerpt_buffer_start =
4645                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4646                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4647                for (buffer_summary, anchor) in excerpt
4648                    .buffer
4649                    .summaries_for_anchors_with_payload::<D, _, _>(
4650                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4651                    )
4652                {
4653                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4654                    let mut position = excerpt_start_position;
4655                    if summary > excerpt_buffer_start {
4656                        position.add_assign(&(summary - excerpt_buffer_start));
4657                    }
4658
4659                    if position > diff_transforms_cursor.start().0 .0 {
4660                        diff_transforms_cursor.seek_forward(
4661                            &ExcerptDimension(position),
4662                            Bias::Left,
4663                            &(),
4664                        );
4665                    }
4666
4667                    summaries.push(self.resolve_summary_for_anchor(
4668                        anchor,
4669                        position,
4670                        &mut diff_transforms_cursor,
4671                    ));
4672                }
4673            } else {
4674                diff_transforms_cursor.seek_forward(
4675                    &ExcerptDimension(excerpt_start_position),
4676                    Bias::Left,
4677                    &(),
4678                );
4679                let position = self.resolve_summary_for_anchor(
4680                    &Anchor::max(),
4681                    excerpt_start_position,
4682                    &mut diff_transforms_cursor,
4683                );
4684                summaries.extend(excerpt_anchors.map(|_| position));
4685            }
4686        }
4687
4688        summaries
4689    }
4690
4691    pub fn dimensions_from_points<'a, D>(
4692        &'a self,
4693        points: impl 'a + IntoIterator<Item = Point>,
4694    ) -> impl 'a + Iterator<Item = D>
4695    where
4696        D: TextDimension + Sub<D, Output = D>,
4697    {
4698        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4699        cursor.seek(&DimensionPair {
4700            key: Point::default(),
4701            value: None,
4702        });
4703        let mut points = points.into_iter();
4704        iter::from_fn(move || {
4705            let point = points.next()?;
4706
4707            cursor.seek_forward(&DimensionPair {
4708                key: point,
4709                value: None,
4710            });
4711
4712            if let Some(region) = cursor.region() {
4713                let overshoot = point - region.range.start.key;
4714                let buffer_point = region.buffer_range.start.key + overshoot;
4715                let mut position = region.range.start.value.unwrap();
4716                position.add_assign(
4717                    &region
4718                        .buffer
4719                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4720                );
4721                return Some(position);
4722            } else {
4723                return Some(D::from_text_summary(&self.text_summary()));
4724            }
4725        })
4726    }
4727
4728    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4729    where
4730        I: 'a + IntoIterator<Item = &'a Anchor>,
4731    {
4732        let mut anchors = anchors.into_iter().enumerate().peekable();
4733        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4734        cursor.next(&());
4735
4736        let mut result = Vec::new();
4737
4738        while let Some((_, anchor)) = anchors.peek() {
4739            let old_excerpt_id = anchor.excerpt_id;
4740
4741            // Find the location where this anchor's excerpt should be.
4742            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4743            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4744
4745            if cursor.item().is_none() {
4746                cursor.next(&());
4747            }
4748
4749            let next_excerpt = cursor.item();
4750            let prev_excerpt = cursor.prev_item();
4751
4752            // Process all of the anchors for this excerpt.
4753            while let Some((_, anchor)) = anchors.peek() {
4754                if anchor.excerpt_id != old_excerpt_id {
4755                    break;
4756                }
4757                let (anchor_ix, anchor) = anchors.next().unwrap();
4758                let mut anchor = *anchor;
4759
4760                // Leave min and max anchors unchanged if invalid or
4761                // if the old excerpt still exists at this location
4762                let mut kept_position = next_excerpt
4763                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4764                    || old_excerpt_id == ExcerptId::max()
4765                    || old_excerpt_id == ExcerptId::min();
4766
4767                // If the old excerpt no longer exists at this location, then attempt to
4768                // find an equivalent position for this anchor in an adjacent excerpt.
4769                if !kept_position {
4770                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4771                        if excerpt.contains(&anchor) {
4772                            anchor.excerpt_id = excerpt.id;
4773                            kept_position = true;
4774                            break;
4775                        }
4776                    }
4777                }
4778
4779                // If there's no adjacent excerpt that contains the anchor's position,
4780                // then report that the anchor has lost its position.
4781                if !kept_position {
4782                    anchor = if let Some(excerpt) = next_excerpt {
4783                        let mut text_anchor = excerpt
4784                            .range
4785                            .context
4786                            .start
4787                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4788                        if text_anchor
4789                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4790                            .is_gt()
4791                        {
4792                            text_anchor = excerpt.range.context.end;
4793                        }
4794                        Anchor {
4795                            buffer_id: Some(excerpt.buffer_id),
4796                            excerpt_id: excerpt.id,
4797                            text_anchor,
4798                            diff_base_anchor: None,
4799                        }
4800                    } else if let Some(excerpt) = prev_excerpt {
4801                        let mut text_anchor = excerpt
4802                            .range
4803                            .context
4804                            .end
4805                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4806                        if text_anchor
4807                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4808                            .is_lt()
4809                        {
4810                            text_anchor = excerpt.range.context.start;
4811                        }
4812                        Anchor {
4813                            buffer_id: Some(excerpt.buffer_id),
4814                            excerpt_id: excerpt.id,
4815                            text_anchor,
4816                            diff_base_anchor: None,
4817                        }
4818                    } else if anchor.text_anchor.bias == Bias::Left {
4819                        Anchor::min()
4820                    } else {
4821                        Anchor::max()
4822                    };
4823                }
4824
4825                result.push((anchor_ix, anchor, kept_position));
4826            }
4827        }
4828        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4829        result
4830    }
4831
4832    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4833        self.anchor_at(position, Bias::Left)
4834    }
4835
4836    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4837        self.anchor_at(position, Bias::Right)
4838    }
4839
4840    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4841        let offset = position.to_offset(self);
4842
4843        // Find the given position in the diff transforms. Determine the corresponding
4844        // offset in the excerpts, and whether the position is within a deleted hunk.
4845        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4846        diff_transforms.seek(&offset, Bias::Right, &());
4847
4848        if offset == diff_transforms.start().0 && bias == Bias::Left {
4849            if let Some(prev_item) = diff_transforms.prev_item() {
4850                match prev_item {
4851                    DiffTransform::DeletedHunk { .. } => {
4852                        diff_transforms.prev(&());
4853                    }
4854                    _ => {}
4855                }
4856            }
4857        }
4858        let offset_in_transform = offset - diff_transforms.start().0;
4859        let mut excerpt_offset = diff_transforms.start().1;
4860        let mut diff_base_anchor = None;
4861        if let Some(DiffTransform::DeletedHunk {
4862            buffer_id,
4863            base_text_byte_range,
4864            has_trailing_newline,
4865            ..
4866        }) = diff_transforms.item()
4867        {
4868            let base_text = self
4869                .diffs
4870                .get(buffer_id)
4871                .and_then(|diff| diff.base_text())
4872                .expect("missing diff base");
4873            if offset_in_transform > base_text_byte_range.len() {
4874                debug_assert!(*has_trailing_newline);
4875                bias = Bias::Right;
4876            } else {
4877                diff_base_anchor = Some(
4878                    base_text.anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4879                );
4880                bias = Bias::Left;
4881            }
4882        } else {
4883            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4884        };
4885
4886        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4887            return Anchor {
4888                buffer_id: Some(buffer_id),
4889                excerpt_id: *excerpt_id,
4890                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4891                diff_base_anchor,
4892            };
4893        }
4894
4895        let mut excerpts = self
4896            .excerpts
4897            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4898        excerpts.seek(&excerpt_offset, Bias::Right, &());
4899        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4900            excerpts.prev(&());
4901        }
4902        if let Some(excerpt) = excerpts.item() {
4903            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4904            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4905                overshoot -= 1;
4906                bias = Bias::Right;
4907            }
4908
4909            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4910            let text_anchor =
4911                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4912            Anchor {
4913                buffer_id: Some(excerpt.buffer_id),
4914                excerpt_id: excerpt.id,
4915                text_anchor,
4916                diff_base_anchor,
4917            }
4918        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4919            Anchor::min()
4920        } else {
4921            Anchor::max()
4922        }
4923    }
4924
4925    /// Returns an anchor for the given excerpt and text anchor,
4926    /// returns None if the excerpt_id is no longer valid.
4927    pub fn anchor_in_excerpt(
4928        &self,
4929        excerpt_id: ExcerptId,
4930        text_anchor: text::Anchor,
4931    ) -> Option<Anchor> {
4932        let locator = self.excerpt_locator_for_id(excerpt_id);
4933        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4934        cursor.seek(locator, Bias::Left, &());
4935        if let Some(excerpt) = cursor.item() {
4936            if excerpt.id == excerpt_id {
4937                let text_anchor = excerpt.clip_anchor(text_anchor);
4938                drop(cursor);
4939                return Some(Anchor {
4940                    buffer_id: Some(excerpt.buffer_id),
4941                    excerpt_id,
4942                    text_anchor,
4943                    diff_base_anchor: None,
4944                });
4945            }
4946        }
4947        None
4948    }
4949
4950    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4951        Some(self.excerpt(excerpt_id)?.range.context.clone())
4952    }
4953
4954    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4955        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4956            true
4957        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4958            excerpt.buffer.can_resolve(&anchor.text_anchor)
4959        } else {
4960            false
4961        }
4962    }
4963
4964    pub fn excerpts(
4965        &self,
4966    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4967        self.excerpts
4968            .iter()
4969            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4970    }
4971
4972    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4973        let excerpts = self.excerpts.cursor(&());
4974        let diff_transforms = self.diff_transforms.cursor(&());
4975        MultiBufferCursor {
4976            excerpts,
4977            diff_transforms,
4978            diffs: &self.diffs,
4979            cached_region: None,
4980        }
4981    }
4982
4983    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4984        let start_locator = self.excerpt_locator_for_id(id);
4985        let mut excerpts = self
4986            .excerpts
4987            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4988        excerpts.seek(&Some(start_locator), Bias::Left, &());
4989        excerpts.prev(&());
4990
4991        let mut diff_transforms = self
4992            .diff_transforms
4993            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4994        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4995        if diff_transforms.end(&()).1 < excerpts.start().1 {
4996            diff_transforms.next(&());
4997        }
4998
4999        let excerpt = excerpts.item()?;
5000        Some(MultiBufferExcerpt {
5001            excerpt,
5002            offset: diff_transforms.start().0 .0,
5003            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5004            excerpt_offset: excerpts.start().1.clone(),
5005            diff_transforms,
5006        })
5007    }
5008
5009    pub fn excerpt_boundaries_in_range<R, T>(
5010        &self,
5011        range: R,
5012    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5013    where
5014        R: RangeBounds<T>,
5015        T: ToOffset,
5016    {
5017        let start_offset;
5018        let start = match range.start_bound() {
5019            Bound::Included(start) => {
5020                start_offset = start.to_offset(self);
5021                Bound::Included(start_offset)
5022            }
5023            Bound::Excluded(_) => {
5024                panic!("not supported")
5025            }
5026            Bound::Unbounded => {
5027                start_offset = 0;
5028                Bound::Unbounded
5029            }
5030        };
5031        let end = match range.end_bound() {
5032            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5033            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5034            Bound::Unbounded => Bound::Unbounded,
5035        };
5036        let bounds = (start, end);
5037
5038        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5039        cursor.seek(&DimensionPair {
5040            key: start_offset,
5041            value: None,
5042        });
5043
5044        if cursor
5045            .region()
5046            .is_some_and(|region| bounds.contains(&region.range.start.key))
5047        {
5048            cursor.prev_excerpt();
5049        } else {
5050            cursor.seek_to_start_of_current_excerpt();
5051        }
5052        let mut prev_region = cursor.region();
5053
5054        cursor.next_excerpt();
5055
5056        let mut visited_end = false;
5057        iter::from_fn(move || loop {
5058            if self.singleton {
5059                return None;
5060            }
5061
5062            let next_region = cursor.region();
5063            cursor.next_excerpt();
5064
5065            let next_region_start = if let Some(region) = &next_region {
5066                if !bounds.contains(&region.range.start.key) {
5067                    prev_region = next_region;
5068                    continue;
5069                }
5070                region.range.start.value.unwrap()
5071            } else {
5072                if !bounds.contains(&self.len()) {
5073                    return None;
5074                }
5075                self.max_point()
5076            };
5077            let next_region_end = if let Some(region) = cursor.region() {
5078                region.range.start.value.unwrap()
5079            } else {
5080                self.max_point()
5081            };
5082
5083            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5084                id: region.excerpt.id,
5085                buffer: region.excerpt.buffer.clone(),
5086                buffer_id: region.excerpt.buffer_id,
5087                range: region.excerpt.range.clone(),
5088                end_row: MultiBufferRow(next_region_start.row),
5089            });
5090
5091            let next = next_region.as_ref().map(|region| ExcerptInfo {
5092                id: region.excerpt.id,
5093                buffer: region.excerpt.buffer.clone(),
5094                buffer_id: region.excerpt.buffer_id,
5095                range: region.excerpt.range.clone(),
5096                end_row: if region.excerpt.has_trailing_newline {
5097                    MultiBufferRow(next_region_end.row - 1)
5098                } else {
5099                    MultiBufferRow(next_region_end.row)
5100                },
5101            });
5102
5103            if next.is_none() {
5104                if visited_end {
5105                    return None;
5106                } else {
5107                    visited_end = true;
5108                }
5109            }
5110
5111            let row = MultiBufferRow(next_region_start.row);
5112
5113            prev_region = next_region;
5114
5115            return Some(ExcerptBoundary { row, prev, next });
5116        })
5117    }
5118
5119    pub fn edit_count(&self) -> usize {
5120        self.edit_count
5121    }
5122
5123    pub fn non_text_state_update_count(&self) -> usize {
5124        self.non_text_state_update_count
5125    }
5126
5127    /// Returns the smallest enclosing bracket ranges containing the given range or
5128    /// None if no brackets contain range or the range is not contained in a single
5129    /// excerpt
5130    ///
5131    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5132    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5133        &self,
5134        range: Range<T>,
5135        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5136    ) -> Option<(Range<usize>, Range<usize>)> {
5137        let range = range.start.to_offset(self)..range.end.to_offset(self);
5138        let mut excerpt = self.excerpt_containing(range.clone())?;
5139        let buffer = excerpt.buffer();
5140        let excerpt_buffer_range = excerpt.buffer_range();
5141
5142        // Filter to ranges contained in the excerpt
5143        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5144            excerpt_buffer_range.contains(&open.start)
5145                && excerpt_buffer_range.contains(&close.end)
5146                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5147        };
5148
5149        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5150            excerpt.map_range_to_buffer(range),
5151            Some(&range_filter),
5152        )?;
5153
5154        Some((
5155            excerpt.map_range_from_buffer(open),
5156            excerpt.map_range_from_buffer(close),
5157        ))
5158    }
5159
5160    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5161    /// not contained in a single excerpt
5162    pub fn enclosing_bracket_ranges<T: ToOffset>(
5163        &self,
5164        range: Range<T>,
5165    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5166        let range = range.start.to_offset(self)..range.end.to_offset(self);
5167        let mut excerpt = self.excerpt_containing(range.clone())?;
5168
5169        Some(
5170            excerpt
5171                .buffer()
5172                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5173                .filter_map(move |pair| {
5174                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5175                        Some((
5176                            excerpt.map_range_from_buffer(pair.open_range),
5177                            excerpt.map_range_from_buffer(pair.close_range),
5178                        ))
5179                    } else {
5180                        None
5181                    }
5182                }),
5183        )
5184    }
5185
5186    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5187    /// not contained in a single excerpt
5188    pub fn text_object_ranges<T: ToOffset>(
5189        &self,
5190        range: Range<T>,
5191        options: TreeSitterOptions,
5192    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5193        let range = range.start.to_offset(self)..range.end.to_offset(self);
5194        self.excerpt_containing(range.clone())
5195            .map(|mut excerpt| {
5196                excerpt
5197                    .buffer()
5198                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5199                    .filter_map(move |(range, text_object)| {
5200                        if excerpt.contains_buffer_range(range.clone()) {
5201                            Some((excerpt.map_range_from_buffer(range), text_object))
5202                        } else {
5203                            None
5204                        }
5205                    })
5206            })
5207            .into_iter()
5208            .flatten()
5209    }
5210
5211    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5212    /// not contained in a single excerpt
5213    pub fn bracket_ranges<T: ToOffset>(
5214        &self,
5215        range: Range<T>,
5216    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5217        let range = range.start.to_offset(self)..range.end.to_offset(self);
5218        let mut excerpt = self.excerpt_containing(range.clone())?;
5219
5220        Some(
5221            excerpt
5222                .buffer()
5223                .bracket_ranges(excerpt.map_range_to_buffer(range))
5224                .filter_map(move |pair| {
5225                    let buffer_range = pair.open_range.start..pair.close_range.end;
5226                    if excerpt.contains_buffer_range(buffer_range) {
5227                        Some((
5228                            excerpt.map_range_from_buffer(pair.open_range),
5229                            excerpt.map_range_from_buffer(pair.close_range),
5230                        ))
5231                    } else {
5232                        None
5233                    }
5234                }),
5235        )
5236    }
5237
5238    pub fn redacted_ranges<'a, T: ToOffset>(
5239        &'a self,
5240        range: Range<T>,
5241        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5242    ) -> impl Iterator<Item = Range<usize>> + 'a {
5243        let range = range.start.to_offset(self)..range.end.to_offset(self);
5244        self.lift_buffer_metadata(range, move |buffer, range| {
5245            if redaction_enabled(buffer.file()) {
5246                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5247            } else {
5248                None
5249            }
5250        })
5251        .map(|(range, _, _)| range)
5252    }
5253
5254    pub fn runnable_ranges(
5255        &self,
5256        range: Range<Anchor>,
5257    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5258        let range = range.start.to_offset(self)..range.end.to_offset(self);
5259        self.lift_buffer_metadata(range, move |buffer, range| {
5260            Some(
5261                buffer
5262                    .runnable_ranges(range.clone())
5263                    .filter(move |runnable| {
5264                        runnable.run_range.start >= range.start
5265                            && runnable.run_range.end < range.end
5266                    })
5267                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5268            )
5269        })
5270        .map(|(run_range, runnable, _)| language::RunnableRange {
5271            run_range,
5272            ..runnable
5273        })
5274    }
5275
5276    pub fn line_indents(
5277        &self,
5278        start_row: MultiBufferRow,
5279        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5280    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5281        let max_point = self.max_point();
5282        let mut cursor = self.cursor::<Point>();
5283        cursor.seek(&Point::new(start_row.0, 0));
5284        iter::from_fn(move || {
5285            let mut region = cursor.region()?;
5286            while !buffer_filter(&region.excerpt.buffer) {
5287                cursor.next();
5288                region = cursor.region()?;
5289            }
5290            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5291            let buffer_start_row =
5292                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5293
5294            let buffer_end_row = if region.is_main_buffer
5295                && (region.has_trailing_newline || region.range.end == max_point)
5296            {
5297                region.buffer_range.end.row
5298            } else {
5299                region.buffer_range.end.row.saturating_sub(1)
5300            };
5301
5302            let line_indents = region
5303                .buffer
5304                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5305            cursor.next();
5306            return Some(line_indents.map(move |(buffer_row, indent)| {
5307                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5308                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5309            }));
5310        })
5311        .flatten()
5312    }
5313
5314    pub fn reversed_line_indents(
5315        &self,
5316        end_row: MultiBufferRow,
5317        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5318    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5319        let max_point = self.max_point();
5320        let mut cursor = self.cursor::<Point>();
5321        cursor.seek(&Point::new(end_row.0, 0));
5322        iter::from_fn(move || {
5323            let mut region = cursor.region()?;
5324            while !buffer_filter(&region.excerpt.buffer) {
5325                cursor.prev();
5326                region = cursor.region()?;
5327            }
5328
5329            let buffer_start_row = region.buffer_range.start.row;
5330            let buffer_end_row = if region.is_main_buffer
5331                && (region.has_trailing_newline || region.range.end == max_point)
5332            {
5333                region.buffer_range.end.row + 1
5334            } else {
5335                region.buffer_range.end.row
5336            };
5337
5338            let overshoot = end_row.0 - region.range.start.row;
5339            let buffer_end_row =
5340                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5341
5342            let line_indents = region
5343                .buffer
5344                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5345            cursor.prev();
5346            return Some(line_indents.map(move |(buffer_row, indent)| {
5347                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5348                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5349            }));
5350        })
5351        .flatten()
5352    }
5353
5354    pub async fn enclosing_indent(
5355        &self,
5356        mut target_row: MultiBufferRow,
5357    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5358        let max_row = MultiBufferRow(self.max_point().row);
5359        if target_row >= max_row {
5360            return None;
5361        }
5362
5363        let mut target_indent = self.line_indent_for_row(target_row);
5364
5365        // If the current row is at the start of an indented block, we want to return this
5366        // block as the enclosing indent.
5367        if !target_indent.is_line_empty() && target_row < max_row {
5368            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5369            if !next_line_indent.is_line_empty()
5370                && target_indent.raw_len() < next_line_indent.raw_len()
5371            {
5372                target_indent = next_line_indent;
5373                target_row.0 += 1;
5374            }
5375        }
5376
5377        const SEARCH_ROW_LIMIT: u32 = 25000;
5378        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5379        const YIELD_INTERVAL: u32 = 100;
5380
5381        let mut accessed_row_counter = 0;
5382
5383        // If there is a blank line at the current row, search for the next non indented lines
5384        if target_indent.is_line_empty() {
5385            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5386            let end =
5387                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5388
5389            let mut non_empty_line_above = None;
5390            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5391                if row < start {
5392                    break;
5393                }
5394                accessed_row_counter += 1;
5395                if accessed_row_counter == YIELD_INTERVAL {
5396                    accessed_row_counter = 0;
5397                    yield_now().await;
5398                }
5399                if !indent.is_line_empty() {
5400                    non_empty_line_above = Some((row, indent));
5401                    break;
5402                }
5403            }
5404
5405            let mut non_empty_line_below = None;
5406            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5407                if row > end {
5408                    break;
5409                }
5410                accessed_row_counter += 1;
5411                if accessed_row_counter == YIELD_INTERVAL {
5412                    accessed_row_counter = 0;
5413                    yield_now().await;
5414                }
5415                if !indent.is_line_empty() {
5416                    non_empty_line_below = Some((row, indent));
5417                    break;
5418                }
5419            }
5420
5421            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5422                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5423                    if above_indent.raw_len() >= below_indent.raw_len() {
5424                        (above_row, above_indent)
5425                    } else {
5426                        (below_row, below_indent)
5427                    }
5428                }
5429                (Some(above), None) => above,
5430                (None, Some(below)) => below,
5431                _ => return None,
5432            };
5433
5434            target_indent = indent;
5435            target_row = row;
5436        }
5437
5438        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5439        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5440
5441        let mut start_indent = None;
5442        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5443            if row < start {
5444                break;
5445            }
5446            accessed_row_counter += 1;
5447            if accessed_row_counter == YIELD_INTERVAL {
5448                accessed_row_counter = 0;
5449                yield_now().await;
5450            }
5451            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5452                start_indent = Some((row, indent));
5453                break;
5454            }
5455        }
5456        let (start_row, start_indent_size) = start_indent?;
5457
5458        let mut end_indent = (end, None);
5459        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5460            if row > end {
5461                break;
5462            }
5463            accessed_row_counter += 1;
5464            if accessed_row_counter == YIELD_INTERVAL {
5465                accessed_row_counter = 0;
5466                yield_now().await;
5467            }
5468            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5469                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5470                break;
5471            }
5472        }
5473        let (end_row, end_indent_size) = end_indent;
5474
5475        let indent = if let Some(end_indent_size) = end_indent_size {
5476            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5477                start_indent_size
5478            } else {
5479                end_indent_size
5480            }
5481        } else {
5482            start_indent_size
5483        };
5484
5485        Some((start_row..end_row, indent))
5486    }
5487
5488    pub fn indent_guides_in_range<T: ToPoint>(
5489        &self,
5490        range: Range<T>,
5491        ignore_disabled_for_language: bool,
5492        cx: &App,
5493    ) -> impl Iterator<Item = IndentGuide> {
5494        let range = range.start.to_point(self)..range.end.to_point(self);
5495        let start_row = MultiBufferRow(range.start.row);
5496        let end_row = MultiBufferRow(range.end.row);
5497
5498        let mut row_indents = self.line_indents(start_row, |buffer| {
5499            let settings =
5500                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5501            settings.indent_guides.enabled || ignore_disabled_for_language
5502        });
5503
5504        let mut result = Vec::new();
5505        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5506
5507        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5508            if first_row > end_row {
5509                break;
5510            }
5511            let current_depth = indent_stack.len() as u32;
5512
5513            let settings =
5514                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5515            let tab_size = settings.tab_size.get() as u32;
5516
5517            // When encountering empty, continue until found useful line indent
5518            // then add to the indent stack with the depth found
5519            let mut found_indent = false;
5520            let mut last_row = first_row;
5521            if line_indent.is_line_empty() {
5522                while !found_indent {
5523                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5524                        break;
5525                    };
5526                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5527                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5528                        break;
5529                    }
5530
5531                    if new_line_indent.is_line_empty() {
5532                        continue;
5533                    }
5534                    last_row = target_row.min(end_row);
5535                    line_indent = new_line_indent;
5536                    found_indent = true;
5537                    break;
5538                }
5539            } else {
5540                found_indent = true
5541            }
5542
5543            let depth = if found_indent {
5544                line_indent.len(tab_size) / tab_size
5545                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5546            } else {
5547                current_depth
5548            };
5549
5550            match depth.cmp(&current_depth) {
5551                cmp::Ordering::Less => {
5552                    for _ in 0..(current_depth - depth) {
5553                        let mut indent = indent_stack.pop().unwrap();
5554                        if last_row != first_row {
5555                            // In this case, we landed on an empty row, had to seek forward,
5556                            // and discovered that the indent we where on is ending.
5557                            // This means that the last display row must
5558                            // be on line that ends this indent range, so we
5559                            // should display the range up to the first non-empty line
5560                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5561                        }
5562
5563                        result.push(indent)
5564                    }
5565                }
5566                cmp::Ordering::Greater => {
5567                    for next_depth in current_depth..depth {
5568                        indent_stack.push(IndentGuide {
5569                            buffer_id: buffer.remote_id(),
5570                            start_row: first_row,
5571                            end_row: last_row,
5572                            depth: next_depth,
5573                            tab_size,
5574                            settings: settings.indent_guides,
5575                        });
5576                    }
5577                }
5578                _ => {}
5579            }
5580
5581            for indent in indent_stack.iter_mut() {
5582                indent.end_row = last_row;
5583            }
5584        }
5585
5586        result.extend(indent_stack);
5587        result.into_iter()
5588    }
5589
5590    pub fn trailing_excerpt_update_count(&self) -> usize {
5591        self.trailing_excerpt_update_count
5592    }
5593
5594    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5595        self.point_to_buffer_offset(point)
5596            .and_then(|(buffer, _)| buffer.file())
5597    }
5598
5599    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5600        self.point_to_buffer_offset(point)
5601            .and_then(|(buffer, offset)| buffer.language_at(offset))
5602    }
5603
5604    pub fn settings_at<'a, T: ToOffset>(
5605        &'a self,
5606        point: T,
5607        cx: &'a App,
5608    ) -> Cow<'a, LanguageSettings> {
5609        let mut language = None;
5610        let mut file = None;
5611        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5612            language = buffer.language_at(offset);
5613            file = buffer.file();
5614        }
5615        language_settings(language.map(|l| l.name()), file, cx)
5616    }
5617
5618    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5619        self.point_to_buffer_offset(point)
5620            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5621    }
5622
5623    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5624        self.point_to_buffer_offset(point)
5625            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5626            .unwrap_or_default()
5627    }
5628
5629    pub fn language_indent_size_at<T: ToOffset>(
5630        &self,
5631        position: T,
5632        cx: &App,
5633    ) -> Option<IndentSize> {
5634        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5635        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5636    }
5637
5638    pub fn is_dirty(&self) -> bool {
5639        self.is_dirty
5640    }
5641
5642    pub fn has_deleted_file(&self) -> bool {
5643        self.has_deleted_file
5644    }
5645
5646    pub fn has_conflict(&self) -> bool {
5647        self.has_conflict
5648    }
5649
5650    pub fn has_diagnostics(&self) -> bool {
5651        self.excerpts
5652            .iter()
5653            .any(|excerpt| excerpt.buffer.has_diagnostics())
5654    }
5655
5656    pub fn diagnostic_group(
5657        &self,
5658        buffer_id: BufferId,
5659        group_id: usize,
5660    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5661        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5662            if buffer.remote_id() != buffer_id {
5663                return None;
5664            };
5665            Some(
5666                buffer
5667                    .diagnostic_group(group_id)
5668                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5669            )
5670        })
5671        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5672    }
5673
5674    pub fn diagnostics_in_range<'a, T>(
5675        &'a self,
5676        range: Range<T>,
5677    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5678    where
5679        T: 'a
5680            + text::ToOffset
5681            + text::FromAnchor
5682            + TextDimension
5683            + Ord
5684            + Sub<T, Output = T>
5685            + fmt::Debug,
5686    {
5687        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5688            Some(
5689                buffer
5690                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5691                    .map(|entry| (entry.range, entry.diagnostic)),
5692            )
5693        })
5694        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5695    }
5696
5697    pub fn syntax_ancestor<T: ToOffset>(
5698        &self,
5699        range: Range<T>,
5700    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5701        let range = range.start.to_offset(self)..range.end.to_offset(self);
5702        let mut excerpt = self.excerpt_containing(range.clone())?;
5703        let node = excerpt
5704            .buffer()
5705            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5706        let node_range = node.byte_range();
5707        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5708            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5709        } else {
5710            MultiOrSingleBufferOffsetRange::Single(node_range)
5711        };
5712        Some((node, range))
5713    }
5714
5715    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5716        let (excerpt_id, _, buffer) = self.as_singleton()?;
5717        let outline = buffer.outline(theme)?;
5718        Some(Outline::new(
5719            outline
5720                .items
5721                .into_iter()
5722                .flat_map(|item| {
5723                    Some(OutlineItem {
5724                        depth: item.depth,
5725                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5726                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5727                        text: item.text,
5728                        highlight_ranges: item.highlight_ranges,
5729                        name_ranges: item.name_ranges,
5730                        body_range: item.body_range.and_then(|body_range| {
5731                            Some(
5732                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5733                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5734                            )
5735                        }),
5736                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5737                            Some(
5738                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5739                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5740                            )
5741                        }),
5742                    })
5743                })
5744                .collect(),
5745        ))
5746    }
5747
5748    pub fn symbols_containing<T: ToOffset>(
5749        &self,
5750        offset: T,
5751        theme: Option<&SyntaxTheme>,
5752    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5753        let anchor = self.anchor_before(offset);
5754        let excerpt_id = anchor.excerpt_id;
5755        let excerpt = self.excerpt(excerpt_id)?;
5756        Some((
5757            excerpt.buffer_id,
5758            excerpt
5759                .buffer
5760                .symbols_containing(anchor.text_anchor, theme)
5761                .into_iter()
5762                .flatten()
5763                .flat_map(|item| {
5764                    Some(OutlineItem {
5765                        depth: item.depth,
5766                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5767                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5768                        text: item.text,
5769                        highlight_ranges: item.highlight_ranges,
5770                        name_ranges: item.name_ranges,
5771                        body_range: item.body_range.and_then(|body_range| {
5772                            Some(
5773                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5774                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5775                            )
5776                        }),
5777                        annotation_range: item.annotation_range.and_then(|body_range| {
5778                            Some(
5779                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5780                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5781                            )
5782                        }),
5783                    })
5784                })
5785                .collect(),
5786        ))
5787    }
5788
5789    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5790        if id == ExcerptId::min() {
5791            Locator::min_ref()
5792        } else if id == ExcerptId::max() {
5793            Locator::max_ref()
5794        } else {
5795            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5796            cursor.seek(&id, Bias::Left, &());
5797            if let Some(entry) = cursor.item() {
5798                if entry.id == id {
5799                    return &entry.locator;
5800                }
5801            }
5802            panic!("invalid excerpt id {:?}", id)
5803        }
5804    }
5805
5806    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5807    fn excerpt_locators_for_ids(
5808        &self,
5809        ids: impl IntoIterator<Item = ExcerptId>,
5810    ) -> SmallVec<[Locator; 1]> {
5811        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5812        sorted_ids.sort_unstable();
5813        let mut locators = SmallVec::new();
5814
5815        while sorted_ids.last() == Some(&ExcerptId::max()) {
5816            sorted_ids.pop();
5817            if let Some(mapping) = self.excerpt_ids.last() {
5818                locators.push(mapping.locator.clone());
5819            }
5820        }
5821
5822        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5823        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5824            sorted_ids.next();
5825            if let Some(mapping) = self.excerpt_ids.first() {
5826                locators.push(mapping.locator.clone());
5827            }
5828        }
5829
5830        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5831        for id in sorted_ids {
5832            if cursor.seek_forward(&id, Bias::Left, &()) {
5833                locators.push(cursor.item().unwrap().locator.clone());
5834            } else {
5835                panic!("invalid excerpt id {:?}", id);
5836            }
5837        }
5838
5839        locators.sort_unstable();
5840        locators
5841    }
5842
5843    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5844        Some(self.excerpt(excerpt_id)?.buffer_id)
5845    }
5846
5847    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5848        Some(&self.excerpt(excerpt_id)?.buffer)
5849    }
5850
5851    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5852        let mut cursor = self
5853            .excerpts
5854            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5855        let locator = self.excerpt_locator_for_id(excerpt_id);
5856        if cursor.seek(&Some(locator), Bias::Left, &()) {
5857            let start = cursor.start().1.clone();
5858            let end = cursor.end(&()).1;
5859            let mut diff_transforms = self
5860                .diff_transforms
5861                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5862            diff_transforms.seek(&start, Bias::Left, &());
5863            let overshoot = start.0 - diff_transforms.start().0 .0;
5864            let start = diff_transforms.start().1 .0 + overshoot;
5865            diff_transforms.seek(&end, Bias::Right, &());
5866            let overshoot = end.0 - diff_transforms.start().0 .0;
5867            let end = diff_transforms.start().1 .0 + overshoot;
5868            Some(start..end)
5869        } else {
5870            None
5871        }
5872    }
5873
5874    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5875        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5876        let locator = self.excerpt_locator_for_id(excerpt_id);
5877        if cursor.seek(&Some(locator), Bias::Left, &()) {
5878            if let Some(excerpt) = cursor.item() {
5879                return Some(excerpt.range.context.clone());
5880            }
5881        }
5882        None
5883    }
5884
5885    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5886        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5887        let locator = self.excerpt_locator_for_id(excerpt_id);
5888        cursor.seek(&Some(locator), Bias::Left, &());
5889        if let Some(excerpt) = cursor.item() {
5890            if excerpt.id == excerpt_id {
5891                return Some(excerpt);
5892            }
5893        }
5894        None
5895    }
5896
5897    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5898    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5899        let range = range.start.to_offset(self)..range.end.to_offset(self);
5900        let mut cursor = self.cursor::<usize>();
5901        cursor.seek(&range.start);
5902
5903        let start_excerpt = cursor.excerpt()?;
5904        if range.end != range.start {
5905            cursor.seek_forward(&range.end);
5906            if cursor.excerpt()?.id != start_excerpt.id {
5907                return None;
5908            }
5909        }
5910
5911        cursor.seek_to_start_of_current_excerpt();
5912        let region = cursor.region()?;
5913        let offset = region.range.start;
5914        let buffer_offset = region.buffer_range.start;
5915        let excerpt_offset = cursor.excerpts.start().clone();
5916        Some(MultiBufferExcerpt {
5917            diff_transforms: cursor.diff_transforms,
5918            excerpt: start_excerpt,
5919            offset,
5920            buffer_offset,
5921            excerpt_offset,
5922        })
5923    }
5924
5925    pub fn selections_in_range<'a>(
5926        &'a self,
5927        range: &'a Range<Anchor>,
5928        include_local: bool,
5929    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5930        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5931        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5932        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5933        cursor.seek(start_locator, Bias::Left, &());
5934        cursor
5935            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5936            .flat_map(move |excerpt| {
5937                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5938                if excerpt.id == range.start.excerpt_id {
5939                    query_range.start = range.start.text_anchor;
5940                }
5941                if excerpt.id == range.end.excerpt_id {
5942                    query_range.end = range.end.text_anchor;
5943                }
5944
5945                excerpt
5946                    .buffer
5947                    .selections_in_range(query_range, include_local)
5948                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5949                        selections.map(move |selection| {
5950                            let mut start = Anchor {
5951                                buffer_id: Some(excerpt.buffer_id),
5952                                excerpt_id: excerpt.id,
5953                                text_anchor: selection.start,
5954                                diff_base_anchor: None,
5955                            };
5956                            let mut end = Anchor {
5957                                buffer_id: Some(excerpt.buffer_id),
5958                                excerpt_id: excerpt.id,
5959                                text_anchor: selection.end,
5960                                diff_base_anchor: None,
5961                            };
5962                            if range.start.cmp(&start, self).is_gt() {
5963                                start = range.start;
5964                            }
5965                            if range.end.cmp(&end, self).is_lt() {
5966                                end = range.end;
5967                            }
5968
5969                            (
5970                                replica_id,
5971                                line_mode,
5972                                cursor_shape,
5973                                Selection {
5974                                    id: selection.id,
5975                                    start,
5976                                    end,
5977                                    reversed: selection.reversed,
5978                                    goal: selection.goal,
5979                                },
5980                            )
5981                        })
5982                    })
5983            })
5984    }
5985
5986    pub fn show_headers(&self) -> bool {
5987        self.show_headers
5988    }
5989
5990    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5991        self.diffs.get(&buffer_id)
5992    }
5993}
5994
5995#[cfg(any(test, feature = "test-support"))]
5996impl MultiBufferSnapshot {
5997    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5998        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5999        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6000        start..end
6001    }
6002
6003    #[cfg(any(test, feature = "test-support"))]
6004    fn check_invariants(&self) {
6005        let excerpts = self.excerpts.items(&());
6006        let excerpt_ids = self.excerpt_ids.items(&());
6007
6008        for (ix, excerpt) in excerpts.iter().enumerate() {
6009            if ix == 0 {
6010                if excerpt.locator <= Locator::min() {
6011                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6012                }
6013            } else if excerpt.locator <= excerpts[ix - 1].locator {
6014                panic!("excerpts are out-of-order: {:?}", excerpts);
6015            }
6016        }
6017
6018        for (ix, entry) in excerpt_ids.iter().enumerate() {
6019            if ix == 0 {
6020                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6021                    panic!("invalid first excerpt id {:?}", entry.id);
6022                }
6023            } else if entry.id <= excerpt_ids[ix - 1].id {
6024                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6025            }
6026        }
6027
6028        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6029            panic!(
6030                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6031                self.excerpts.summary().text.len,
6032                self.diff_transforms.summary().input,
6033                self.diff_transforms.items(&()),
6034            );
6035        }
6036
6037        let mut prev_transform: Option<&DiffTransform> = None;
6038        for item in self.diff_transforms.iter() {
6039            if let DiffTransform::BufferContent {
6040                summary,
6041                inserted_hunk_info,
6042            } = item
6043            {
6044                if let Some(DiffTransform::BufferContent {
6045                    inserted_hunk_info: prev_inserted_hunk_info,
6046                    ..
6047                }) = prev_transform
6048                {
6049                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6050                        panic!(
6051                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6052                            self.diff_transforms.items(&()));
6053                    }
6054                }
6055                if summary.len == 0 && !self.is_empty() {
6056                    panic!("empty buffer content transform");
6057                }
6058            }
6059            prev_transform = Some(item);
6060        }
6061    }
6062}
6063
6064impl<'a, D> MultiBufferCursor<'a, D>
6065where
6066    D: TextDimension + Ord + Sub<D, Output = D>,
6067{
6068    fn seek(&mut self, position: &D) {
6069        self.cached_region.take();
6070        self.diff_transforms
6071            .seek(&OutputDimension(*position), Bias::Right, &());
6072        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6073            self.diff_transforms.prev(&());
6074        }
6075
6076        let mut excerpt_position = self.diff_transforms.start().1 .0;
6077        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6078            let overshoot = *position - self.diff_transforms.start().0 .0;
6079            excerpt_position.add_assign(&overshoot);
6080        }
6081
6082        self.excerpts
6083            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6084        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6085            self.excerpts.prev(&());
6086        }
6087    }
6088
6089    fn seek_forward(&mut self, position: &D) {
6090        self.cached_region.take();
6091        self.diff_transforms
6092            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6093        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6094            self.diff_transforms.prev(&());
6095        }
6096
6097        let overshoot = *position - self.diff_transforms.start().0 .0;
6098        let mut excerpt_position = self.diff_transforms.start().1 .0;
6099        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6100            excerpt_position.add_assign(&overshoot);
6101        }
6102
6103        self.excerpts
6104            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6105        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6106            self.excerpts.prev(&());
6107        }
6108    }
6109
6110    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
6111        self.cached_region.take();
6112        if let Some(excerpt) = self.excerpts.item() {
6113            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
6114            let position_in_excerpt = *position - excerpt_start;
6115            let mut excerpt_position = self.excerpts.start().0;
6116            excerpt_position.add_assign(&position_in_excerpt);
6117            self.diff_transforms
6118                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
6119            if self.diff_transforms.item().is_none() {
6120                self.diff_transforms.next(&());
6121            }
6122        }
6123    }
6124
6125    fn next_excerpt(&mut self) {
6126        self.excerpts.next(&());
6127        self.seek_to_start_of_current_excerpt();
6128    }
6129
6130    fn prev_excerpt(&mut self) {
6131        self.excerpts.prev(&());
6132        self.seek_to_start_of_current_excerpt();
6133    }
6134
6135    fn seek_to_start_of_current_excerpt(&mut self) {
6136        self.cached_region.take();
6137        self.diff_transforms
6138            .seek(self.excerpts.start(), Bias::Left, &());
6139        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6140            && self.diff_transforms.start().1 < *self.excerpts.start()
6141            && self.diff_transforms.next_item().is_some()
6142        {
6143            self.diff_transforms.next(&());
6144        }
6145    }
6146
6147    fn next(&mut self) {
6148        self.cached_region.take();
6149        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6150            cmp::Ordering::Less => self.diff_transforms.next(&()),
6151            cmp::Ordering::Greater => self.excerpts.next(&()),
6152            cmp::Ordering::Equal => {
6153                self.diff_transforms.next(&());
6154                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6155                    || self.diff_transforms.item().is_none()
6156                {
6157                    self.excerpts.next(&());
6158                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6159                    self.diff_transforms.item()
6160                {
6161                    if self
6162                        .excerpts
6163                        .item()
6164                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6165                    {
6166                        self.excerpts.next(&());
6167                    }
6168                }
6169            }
6170        }
6171    }
6172
6173    fn prev(&mut self) {
6174        self.cached_region.take();
6175        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6176            cmp::Ordering::Less => self.excerpts.prev(&()),
6177            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6178            cmp::Ordering::Equal => {
6179                self.diff_transforms.prev(&());
6180                if self.diff_transforms.start().1 < *self.excerpts.start()
6181                    || self.diff_transforms.item().is_none()
6182                {
6183                    self.excerpts.prev(&());
6184                }
6185            }
6186        }
6187    }
6188
6189    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6190        if self.cached_region.is_none() {
6191            self.cached_region = self.build_region();
6192        }
6193        self.cached_region.clone()
6194    }
6195
6196    fn is_at_end_of_excerpt(&mut self) -> bool {
6197        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6198            return false;
6199        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6200            || self.diff_transforms.item().is_none()
6201        {
6202            return true;
6203        }
6204
6205        let next_transform = self.diff_transforms.next_item();
6206        next_transform.map_or(true, |next_transform| match next_transform {
6207            DiffTransform::BufferContent { .. } => true,
6208            DiffTransform::DeletedHunk { hunk_info, .. } => self
6209                .excerpts
6210                .item()
6211                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6212        })
6213    }
6214
6215    fn main_buffer_position(&self) -> Option<D> {
6216        let excerpt = self.excerpts.item()?;
6217        let buffer = &excerpt.buffer;
6218        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6219        let mut buffer_start = buffer_context_start;
6220        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6221        buffer_start.add_assign(&overshoot);
6222        Some(buffer_start)
6223    }
6224
6225    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6226        let excerpt = self.excerpts.item()?;
6227        match self.diff_transforms.item()? {
6228            DiffTransform::DeletedHunk {
6229                buffer_id,
6230                base_text_byte_range,
6231                has_trailing_newline,
6232                hunk_info,
6233                ..
6234            } => {
6235                let diff = self.diffs.get(&buffer_id)?;
6236                let buffer = diff.base_text()?;
6237                let mut rope_cursor = buffer.as_rope().cursor(0);
6238                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6239                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6240                let mut buffer_end = buffer_start;
6241                buffer_end.add_assign(&buffer_range_len);
6242                let start = self.diff_transforms.start().0 .0;
6243                let end = self.diff_transforms.end(&()).0 .0;
6244                return Some(MultiBufferRegion {
6245                    buffer,
6246                    excerpt,
6247                    has_trailing_newline: *has_trailing_newline,
6248                    is_main_buffer: false,
6249                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6250                        hunk_info.hunk_secondary_status,
6251                    )),
6252                    buffer_range: buffer_start..buffer_end,
6253                    range: start..end,
6254                });
6255            }
6256            DiffTransform::BufferContent {
6257                inserted_hunk_info, ..
6258            } => {
6259                let buffer = &excerpt.buffer;
6260                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6261
6262                let mut start = self.diff_transforms.start().0 .0;
6263                let mut buffer_start = buffer_context_start;
6264                if self.diff_transforms.start().1 < *self.excerpts.start() {
6265                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6266                    start.add_assign(&overshoot);
6267                } else {
6268                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6269                    buffer_start.add_assign(&overshoot);
6270                }
6271
6272                let mut end;
6273                let mut buffer_end;
6274                let has_trailing_newline;
6275                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6276                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6277                    end = self.diff_transforms.end(&()).0 .0;
6278                    buffer_end = buffer_context_start;
6279                    buffer_end.add_assign(&overshoot);
6280                    has_trailing_newline = false;
6281                } else {
6282                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6283                    end = self.diff_transforms.start().0 .0;
6284                    end.add_assign(&overshoot);
6285                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6286                    has_trailing_newline = excerpt.has_trailing_newline;
6287                };
6288
6289                Some(MultiBufferRegion {
6290                    buffer,
6291                    excerpt,
6292                    has_trailing_newline,
6293                    is_main_buffer: true,
6294                    diff_hunk_status: inserted_hunk_info
6295                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6296                    buffer_range: buffer_start..buffer_end,
6297                    range: start..end,
6298                })
6299            }
6300        }
6301    }
6302
6303    fn excerpt(&self) -> Option<&'a Excerpt> {
6304        self.excerpts.item()
6305    }
6306}
6307
6308impl History {
6309    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6310        self.transaction_depth += 1;
6311        if self.transaction_depth == 1 {
6312            let id = self.next_transaction_id.tick();
6313            self.undo_stack.push(Transaction {
6314                id,
6315                buffer_transactions: Default::default(),
6316                first_edit_at: now,
6317                last_edit_at: now,
6318                suppress_grouping: false,
6319            });
6320            Some(id)
6321        } else {
6322            None
6323        }
6324    }
6325
6326    fn end_transaction(
6327        &mut self,
6328        now: Instant,
6329        buffer_transactions: HashMap<BufferId, TransactionId>,
6330    ) -> bool {
6331        assert_ne!(self.transaction_depth, 0);
6332        self.transaction_depth -= 1;
6333        if self.transaction_depth == 0 {
6334            if buffer_transactions.is_empty() {
6335                self.undo_stack.pop();
6336                false
6337            } else {
6338                self.redo_stack.clear();
6339                let transaction = self.undo_stack.last_mut().unwrap();
6340                transaction.last_edit_at = now;
6341                for (buffer_id, transaction_id) in buffer_transactions {
6342                    transaction
6343                        .buffer_transactions
6344                        .entry(buffer_id)
6345                        .or_insert(transaction_id);
6346                }
6347                true
6348            }
6349        } else {
6350            false
6351        }
6352    }
6353
6354    fn push_transaction<'a, T>(
6355        &mut self,
6356        buffer_transactions: T,
6357        now: Instant,
6358        cx: &Context<MultiBuffer>,
6359    ) where
6360        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6361    {
6362        assert_eq!(self.transaction_depth, 0);
6363        let transaction = Transaction {
6364            id: self.next_transaction_id.tick(),
6365            buffer_transactions: buffer_transactions
6366                .into_iter()
6367                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6368                .collect(),
6369            first_edit_at: now,
6370            last_edit_at: now,
6371            suppress_grouping: false,
6372        };
6373        if !transaction.buffer_transactions.is_empty() {
6374            self.undo_stack.push(transaction);
6375            self.redo_stack.clear();
6376        }
6377    }
6378
6379    fn finalize_last_transaction(&mut self) {
6380        if let Some(transaction) = self.undo_stack.last_mut() {
6381            transaction.suppress_grouping = true;
6382        }
6383    }
6384
6385    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6386        if let Some(ix) = self
6387            .undo_stack
6388            .iter()
6389            .rposition(|transaction| transaction.id == transaction_id)
6390        {
6391            Some(self.undo_stack.remove(ix))
6392        } else if let Some(ix) = self
6393            .redo_stack
6394            .iter()
6395            .rposition(|transaction| transaction.id == transaction_id)
6396        {
6397            Some(self.redo_stack.remove(ix))
6398        } else {
6399            None
6400        }
6401    }
6402
6403    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6404        self.undo_stack
6405            .iter()
6406            .find(|transaction| transaction.id == transaction_id)
6407            .or_else(|| {
6408                self.redo_stack
6409                    .iter()
6410                    .find(|transaction| transaction.id == transaction_id)
6411            })
6412    }
6413
6414    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6415        self.undo_stack
6416            .iter_mut()
6417            .find(|transaction| transaction.id == transaction_id)
6418            .or_else(|| {
6419                self.redo_stack
6420                    .iter_mut()
6421                    .find(|transaction| transaction.id == transaction_id)
6422            })
6423    }
6424
6425    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6426        assert_eq!(self.transaction_depth, 0);
6427        if let Some(transaction) = self.undo_stack.pop() {
6428            self.redo_stack.push(transaction);
6429            self.redo_stack.last_mut()
6430        } else {
6431            None
6432        }
6433    }
6434
6435    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6436        assert_eq!(self.transaction_depth, 0);
6437        if let Some(transaction) = self.redo_stack.pop() {
6438            self.undo_stack.push(transaction);
6439            self.undo_stack.last_mut()
6440        } else {
6441            None
6442        }
6443    }
6444
6445    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6446        let ix = self
6447            .undo_stack
6448            .iter()
6449            .rposition(|transaction| transaction.id == transaction_id)?;
6450        let transaction = self.undo_stack.remove(ix);
6451        self.redo_stack.push(transaction);
6452        self.redo_stack.last()
6453    }
6454
6455    fn group(&mut self) -> Option<TransactionId> {
6456        let mut count = 0;
6457        let mut transactions = self.undo_stack.iter();
6458        if let Some(mut transaction) = transactions.next_back() {
6459            while let Some(prev_transaction) = transactions.next_back() {
6460                if !prev_transaction.suppress_grouping
6461                    && transaction.first_edit_at - prev_transaction.last_edit_at
6462                        <= self.group_interval
6463                {
6464                    transaction = prev_transaction;
6465                    count += 1;
6466                } else {
6467                    break;
6468                }
6469            }
6470        }
6471        self.group_trailing(count)
6472    }
6473
6474    fn group_until(&mut self, transaction_id: TransactionId) {
6475        let mut count = 0;
6476        for transaction in self.undo_stack.iter().rev() {
6477            if transaction.id == transaction_id {
6478                self.group_trailing(count);
6479                break;
6480            } else if transaction.suppress_grouping {
6481                break;
6482            } else {
6483                count += 1;
6484            }
6485        }
6486    }
6487
6488    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6489        let new_len = self.undo_stack.len() - n;
6490        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6491        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6492            if let Some(transaction) = transactions_to_merge.last() {
6493                last_transaction.last_edit_at = transaction.last_edit_at;
6494            }
6495            for to_merge in transactions_to_merge {
6496                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6497                    last_transaction
6498                        .buffer_transactions
6499                        .entry(*buffer_id)
6500                        .or_insert(*transaction_id);
6501                }
6502            }
6503        }
6504
6505        self.undo_stack.truncate(new_len);
6506        self.undo_stack.last().map(|t| t.id)
6507    }
6508}
6509
6510impl Excerpt {
6511    fn new(
6512        id: ExcerptId,
6513        locator: Locator,
6514        buffer_id: BufferId,
6515        buffer: BufferSnapshot,
6516        range: ExcerptRange<text::Anchor>,
6517        has_trailing_newline: bool,
6518    ) -> Self {
6519        Excerpt {
6520            id,
6521            locator,
6522            max_buffer_row: range.context.end.to_point(&buffer).row,
6523            text_summary: buffer
6524                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6525            buffer_id,
6526            buffer,
6527            range,
6528            has_trailing_newline,
6529        }
6530    }
6531
6532    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6533        let content_start = self.range.context.start.to_offset(&self.buffer);
6534        let chunks_start = content_start + range.start;
6535        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6536
6537        let footer_height = if self.has_trailing_newline
6538            && range.start <= self.text_summary.len
6539            && range.end > self.text_summary.len
6540        {
6541            1
6542        } else {
6543            0
6544        };
6545
6546        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6547
6548        ExcerptChunks {
6549            excerpt_id: self.id,
6550            content_chunks,
6551            footer_height,
6552        }
6553    }
6554
6555    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6556        let content_start = self.range.context.start.to_offset(&self.buffer);
6557        let chunks_start = content_start + range.start;
6558        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6559        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6560        excerpt_chunks.footer_height = if self.has_trailing_newline
6561            && range.start <= self.text_summary.len
6562            && range.end > self.text_summary.len
6563        {
6564            1
6565        } else {
6566            0
6567        };
6568    }
6569
6570    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6571        if text_anchor
6572            .cmp(&self.range.context.start, &self.buffer)
6573            .is_lt()
6574        {
6575            self.range.context.start
6576        } else if text_anchor
6577            .cmp(&self.range.context.end, &self.buffer)
6578            .is_gt()
6579        {
6580            self.range.context.end
6581        } else {
6582            text_anchor
6583        }
6584    }
6585
6586    fn contains(&self, anchor: &Anchor) -> bool {
6587        Some(self.buffer_id) == anchor.buffer_id
6588            && self
6589                .range
6590                .context
6591                .start
6592                .cmp(&anchor.text_anchor, &self.buffer)
6593                .is_le()
6594            && self
6595                .range
6596                .context
6597                .end
6598                .cmp(&anchor.text_anchor, &self.buffer)
6599                .is_ge()
6600    }
6601
6602    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6603    fn buffer_start_offset(&self) -> usize {
6604        self.range.context.start.to_offset(&self.buffer)
6605    }
6606
6607    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6608    fn buffer_end_offset(&self) -> usize {
6609        self.buffer_start_offset() + self.text_summary.len
6610    }
6611}
6612
6613impl<'a> MultiBufferExcerpt<'a> {
6614    pub fn id(&self) -> ExcerptId {
6615        self.excerpt.id
6616    }
6617
6618    pub fn buffer_id(&self) -> BufferId {
6619        self.excerpt.buffer_id
6620    }
6621
6622    pub fn start_anchor(&self) -> Anchor {
6623        Anchor {
6624            buffer_id: Some(self.excerpt.buffer_id),
6625            excerpt_id: self.excerpt.id,
6626            text_anchor: self.excerpt.range.context.start,
6627            diff_base_anchor: None,
6628        }
6629    }
6630
6631    pub fn end_anchor(&self) -> Anchor {
6632        Anchor {
6633            buffer_id: Some(self.excerpt.buffer_id),
6634            excerpt_id: self.excerpt.id,
6635            text_anchor: self.excerpt.range.context.end,
6636            diff_base_anchor: None,
6637        }
6638    }
6639
6640    pub fn buffer(&self) -> &'a BufferSnapshot {
6641        &self.excerpt.buffer
6642    }
6643
6644    pub fn buffer_range(&self) -> Range<usize> {
6645        self.buffer_offset
6646            ..self
6647                .excerpt
6648                .range
6649                .context
6650                .end
6651                .to_offset(&self.excerpt.buffer.text)
6652    }
6653
6654    pub fn start_offset(&self) -> usize {
6655        self.offset
6656    }
6657
6658    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6659    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6660        self.map_range_to_buffer(offset..offset).start
6661    }
6662
6663    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6664    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6665        self.diff_transforms
6666            .seek(&OutputDimension(range.start), Bias::Right, &());
6667        let start = self.map_offset_to_buffer_internal(range.start);
6668        let end = if range.end > range.start {
6669            self.diff_transforms
6670                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6671            self.map_offset_to_buffer_internal(range.end)
6672        } else {
6673            start
6674        };
6675        start..end
6676    }
6677
6678    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6679        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6680        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6681            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6682        };
6683        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6684        self.buffer_offset + offset_in_excerpt
6685    }
6686
6687    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6688    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6689        self.map_range_from_buffer(buffer_offset..buffer_offset)
6690            .start
6691    }
6692
6693    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6694    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6695        if buffer_range.start < self.buffer_offset {
6696            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6697            return buffer_range;
6698        }
6699        let overshoot = buffer_range.start - self.buffer_offset;
6700        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6701        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6702        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6703            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6704            return buffer_range;
6705        }
6706        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6707        let start = self.diff_transforms.start().0 .0 + overshoot;
6708
6709        let end = if buffer_range.end > buffer_range.start {
6710            let overshoot = buffer_range.end - self.buffer_offset;
6711            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6712            self.diff_transforms
6713                .seek_forward(&excerpt_offset, Bias::Right, &());
6714            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6715            self.diff_transforms.start().0 .0 + overshoot
6716        } else {
6717            start
6718        };
6719
6720        start..end
6721    }
6722
6723    /// Returns true if the entirety of the given range is in the buffer's excerpt
6724    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6725        range.start >= self.excerpt.buffer_start_offset()
6726            && range.end <= self.excerpt.buffer_end_offset()
6727    }
6728
6729    pub fn max_buffer_row(&self) -> u32 {
6730        self.excerpt.max_buffer_row
6731    }
6732}
6733
6734impl ExcerptId {
6735    pub fn min() -> Self {
6736        Self(0)
6737    }
6738
6739    pub fn max() -> Self {
6740        Self(usize::MAX)
6741    }
6742
6743    pub fn to_proto(&self) -> u64 {
6744        self.0 as _
6745    }
6746
6747    pub fn from_proto(proto: u64) -> Self {
6748        Self(proto as _)
6749    }
6750
6751    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6752        let a = snapshot.excerpt_locator_for_id(*self);
6753        let b = snapshot.excerpt_locator_for_id(*other);
6754        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6755    }
6756}
6757
6758impl From<ExcerptId> for usize {
6759    fn from(val: ExcerptId) -> Self {
6760        val.0
6761    }
6762}
6763
6764impl fmt::Debug for Excerpt {
6765    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6766        f.debug_struct("Excerpt")
6767            .field("id", &self.id)
6768            .field("locator", &self.locator)
6769            .field("buffer_id", &self.buffer_id)
6770            .field("range", &self.range)
6771            .field("text_summary", &self.text_summary)
6772            .field("has_trailing_newline", &self.has_trailing_newline)
6773            .finish()
6774    }
6775}
6776
6777impl sum_tree::Item for Excerpt {
6778    type Summary = ExcerptSummary;
6779
6780    fn summary(&self, _cx: &()) -> Self::Summary {
6781        let mut text = self.text_summary;
6782        if self.has_trailing_newline {
6783            text += TextSummary::from("\n");
6784        }
6785        ExcerptSummary {
6786            excerpt_id: self.id,
6787            excerpt_locator: self.locator.clone(),
6788            widest_line_number: self.max_buffer_row,
6789            text,
6790        }
6791    }
6792}
6793
6794impl sum_tree::Item for ExcerptIdMapping {
6795    type Summary = ExcerptId;
6796
6797    fn summary(&self, _cx: &()) -> Self::Summary {
6798        self.id
6799    }
6800}
6801
6802impl sum_tree::KeyedItem for ExcerptIdMapping {
6803    type Key = ExcerptId;
6804
6805    fn key(&self) -> Self::Key {
6806        self.id
6807    }
6808}
6809
6810impl DiffTransform {
6811    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6812        match self {
6813            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6814            DiffTransform::BufferContent {
6815                inserted_hunk_info, ..
6816            } => *inserted_hunk_info,
6817        }
6818    }
6819}
6820
6821impl sum_tree::Item for DiffTransform {
6822    type Summary = DiffTransformSummary;
6823
6824    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6825        match self {
6826            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6827                input: *summary,
6828                output: *summary,
6829            },
6830            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6831                input: TextSummary::default(),
6832                output: *summary,
6833            },
6834        }
6835    }
6836}
6837
6838impl DiffTransformSummary {
6839    fn excerpt_len(&self) -> ExcerptOffset {
6840        ExcerptOffset::new(self.input.len)
6841    }
6842}
6843
6844impl sum_tree::Summary for DiffTransformSummary {
6845    type Context = ();
6846
6847    fn zero(_: &Self::Context) -> Self {
6848        DiffTransformSummary {
6849            input: TextSummary::default(),
6850            output: TextSummary::default(),
6851        }
6852    }
6853
6854    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6855        self.input += &summary.input;
6856        self.output += &summary.output;
6857    }
6858}
6859
6860impl sum_tree::Summary for ExcerptId {
6861    type Context = ();
6862
6863    fn zero(_cx: &()) -> Self {
6864        Default::default()
6865    }
6866
6867    fn add_summary(&mut self, other: &Self, _: &()) {
6868        *self = *other;
6869    }
6870}
6871
6872impl sum_tree::Summary for ExcerptSummary {
6873    type Context = ();
6874
6875    fn zero(_cx: &()) -> Self {
6876        Default::default()
6877    }
6878
6879    fn add_summary(&mut self, summary: &Self, _: &()) {
6880        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6881        self.excerpt_locator = summary.excerpt_locator.clone();
6882        self.text.add_summary(&summary.text, &());
6883        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6884    }
6885}
6886
6887impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6888    fn zero(_cx: &()) -> Self {
6889        Default::default()
6890    }
6891
6892    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6893        self.value += summary.text.len;
6894    }
6895}
6896
6897impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6898    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6899        Ord::cmp(&self.value, &cursor_location.text.len)
6900    }
6901}
6902
6903impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6904    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6905        Ord::cmp(&Some(self), cursor_location)
6906    }
6907}
6908
6909impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
6910    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6911        Ord::cmp(self, &cursor_location.excerpt_locator)
6912    }
6913}
6914
6915impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6916    fn zero(_cx: &()) -> Self {
6917        Default::default()
6918    }
6919
6920    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6921        self.value += summary.text.lines;
6922    }
6923}
6924
6925impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6926    for ExcerptDimension<D>
6927{
6928    fn zero(_: &()) -> Self {
6929        ExcerptDimension(D::default())
6930    }
6931
6932    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6933        self.0.add_assign(&D::from_text_summary(&summary.text))
6934    }
6935}
6936
6937impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6938    fn zero(_cx: &()) -> Self {
6939        Default::default()
6940    }
6941
6942    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6943        *self = Some(&summary.excerpt_locator);
6944    }
6945}
6946
6947impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6948    fn zero(_cx: &()) -> Self {
6949        Default::default()
6950    }
6951
6952    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6953        *self = Some(summary.excerpt_id);
6954    }
6955}
6956
6957#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6958struct ExcerptDimension<T>(T);
6959
6960#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6961struct OutputDimension<T>(T);
6962
6963impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6964    fn zero(_: &()) -> Self {
6965        ExcerptOffset::new(0)
6966    }
6967
6968    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6969        self.value += summary.input.len;
6970    }
6971}
6972
6973impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6974    fn zero(_: &()) -> Self {
6975        ExcerptPoint::new(0, 0)
6976    }
6977
6978    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6979        self.value += summary.input.lines;
6980    }
6981}
6982
6983impl<'a, D: TextDimension + Ord>
6984    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransformSummary> for ExcerptDimension<D>
6985{
6986    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6987        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6988    }
6989}
6990
6991impl<'a, D: TextDimension + Ord>
6992    sum_tree::SeekTarget<'a, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6993    for ExcerptDimension<D>
6994{
6995    fn cmp(
6996        &self,
6997        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6998        _: &(),
6999    ) -> cmp::Ordering {
7000        Ord::cmp(&self.0, &cursor_location.1 .0)
7001    }
7002}
7003
7004impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7005    fn zero(_: &()) -> Self {
7006        ExcerptDimension(D::default())
7007    }
7008
7009    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7010        self.0.add_assign(&D::from_text_summary(&summary.input))
7011    }
7012}
7013
7014impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7015    fn zero(_: &()) -> Self {
7016        OutputDimension(D::default())
7017    }
7018
7019    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7020        self.0.add_assign(&D::from_text_summary(&summary.output))
7021    }
7022}
7023
7024impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7025    fn zero(_: &()) -> Self {
7026        TextSummary::default()
7027    }
7028
7029    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7030        *self += summary.output
7031    }
7032}
7033
7034impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7035    fn zero(_: &()) -> Self {
7036        0
7037    }
7038
7039    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7040        *self += summary.output.len
7041    }
7042}
7043
7044impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7045    fn zero(_: &()) -> Self {
7046        Point::new(0, 0)
7047    }
7048
7049    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7050        *self += summary.output.lines
7051    }
7052}
7053
7054impl<'a> MultiBufferRows<'a> {
7055    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7056        self.point = Point::new(row, 0);
7057        self.cursor.seek(&self.point);
7058    }
7059}
7060
7061impl<'a> Iterator for MultiBufferRows<'a> {
7062    type Item = RowInfo;
7063
7064    fn next(&mut self) -> Option<Self::Item> {
7065        if self.is_empty && self.point.row == 0 {
7066            self.point += Point::new(1, 0);
7067            return Some(RowInfo {
7068                buffer_id: None,
7069                buffer_row: Some(0),
7070                multibuffer_row: Some(MultiBufferRow(0)),
7071                diff_status: None,
7072            });
7073        }
7074
7075        let mut region = self.cursor.region()?;
7076        while self.point >= region.range.end {
7077            self.cursor.next();
7078            if let Some(next_region) = self.cursor.region() {
7079                region = next_region;
7080            } else {
7081                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7082                    let multibuffer_row = MultiBufferRow(self.point.row);
7083                    self.point += Point::new(1, 0);
7084                    let last_excerpt = self
7085                        .cursor
7086                        .excerpts
7087                        .item()
7088                        .or(self.cursor.excerpts.prev_item())?;
7089                    let last_row = last_excerpt
7090                        .range
7091                        .context
7092                        .end
7093                        .to_point(&last_excerpt.buffer)
7094                        .row;
7095                    return Some(RowInfo {
7096                        buffer_id: Some(last_excerpt.buffer_id),
7097                        buffer_row: Some(last_row),
7098                        multibuffer_row: Some(multibuffer_row),
7099                        diff_status: None,
7100                    });
7101                } else {
7102                    return None;
7103                }
7104            };
7105        }
7106
7107        let overshoot = self.point - region.range.start;
7108        let buffer_point = region.buffer_range.start + overshoot;
7109        let result = Some(RowInfo {
7110            buffer_id: Some(region.buffer.remote_id()),
7111            buffer_row: Some(buffer_point.row),
7112            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7113            diff_status: region
7114                .diff_hunk_status
7115                .filter(|_| self.point < region.range.end),
7116        });
7117        self.point += Point::new(1, 0);
7118        result
7119    }
7120}
7121
7122impl<'a> MultiBufferChunks<'a> {
7123    pub fn offset(&self) -> usize {
7124        self.range.start
7125    }
7126
7127    pub fn seek(&mut self, range: Range<usize>) {
7128        self.diff_transforms.seek(&range.end, Bias::Right, &());
7129        let mut excerpt_end = self.diff_transforms.start().1;
7130        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7131            let overshoot = range.end - self.diff_transforms.start().0;
7132            excerpt_end.value += overshoot;
7133        }
7134
7135        self.diff_transforms.seek(&range.start, Bias::Right, &());
7136        let mut excerpt_start = self.diff_transforms.start().1;
7137        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7138            let overshoot = range.start - self.diff_transforms.start().0;
7139            excerpt_start.value += overshoot;
7140        }
7141
7142        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7143        self.buffer_chunk.take();
7144        self.range = range;
7145    }
7146
7147    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7148        self.excerpt_offset_range = new_range.clone();
7149        self.excerpts.seek(&new_range.start, Bias::Right, &());
7150        if let Some(excerpt) = self.excerpts.item() {
7151            let excerpt_start = *self.excerpts.start();
7152            if let Some(excerpt_chunks) = self
7153                .excerpt_chunks
7154                .as_mut()
7155                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7156            {
7157                excerpt.seek_chunks(
7158                    excerpt_chunks,
7159                    (self.excerpt_offset_range.start - excerpt_start).value
7160                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7161                );
7162            } else {
7163                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7164                    (self.excerpt_offset_range.start - excerpt_start).value
7165                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7166                    self.language_aware,
7167                ));
7168            }
7169        } else {
7170            self.excerpt_chunks = None;
7171        }
7172    }
7173
7174    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7175        loop {
7176            if self.excerpt_offset_range.is_empty() {
7177                return None;
7178            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7179                self.excerpt_offset_range.start.value += chunk.text.len();
7180                return Some(chunk);
7181            } else {
7182                self.excerpts.next(&());
7183                let excerpt = self.excerpts.item()?;
7184                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7185                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7186                    self.language_aware,
7187                ));
7188            }
7189        }
7190    }
7191}
7192
7193impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7194    type Item = &'a str;
7195
7196    fn next(&mut self) -> Option<Self::Item> {
7197        let mut region = self.cursor.region()?;
7198        if self.offset == region.range.start {
7199            self.cursor.prev();
7200            region = self.cursor.region()?;
7201            let start_overshoot = self.start.saturating_sub(region.range.start);
7202            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7203                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7204            ));
7205        }
7206
7207        if self.offset == region.range.end && region.has_trailing_newline {
7208            self.offset -= 1;
7209            Some("\n")
7210        } else {
7211            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7212            self.offset -= chunk.len();
7213            Some(chunk)
7214        }
7215    }
7216}
7217
7218impl<'a> Iterator for MultiBufferChunks<'a> {
7219    type Item = Chunk<'a>;
7220
7221    fn next(&mut self) -> Option<Chunk<'a>> {
7222        if self.range.start >= self.range.end {
7223            return None;
7224        }
7225        if self.range.start == self.diff_transforms.end(&()).0 {
7226            self.diff_transforms.next(&());
7227        }
7228
7229        let diff_transform_start = self.diff_transforms.start().0;
7230        let diff_transform_end = self.diff_transforms.end(&()).0;
7231        debug_assert!(self.range.start < diff_transform_end);
7232
7233        let diff_transform = self.diff_transforms.item()?;
7234        match diff_transform {
7235            DiffTransform::BufferContent { .. } => {
7236                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7237                    chunk
7238                } else {
7239                    let chunk = self.next_excerpt_chunk().unwrap();
7240                    self.buffer_chunk.insert(chunk)
7241                };
7242
7243                let chunk_end = self.range.start + chunk.text.len();
7244                let diff_transform_end = diff_transform_end.min(self.range.end);
7245
7246                if diff_transform_end < chunk_end {
7247                    let (before, after) =
7248                        chunk.text.split_at(diff_transform_end - self.range.start);
7249                    self.range.start = diff_transform_end;
7250                    chunk.text = after;
7251                    Some(Chunk {
7252                        text: before,
7253                        ..chunk.clone()
7254                    })
7255                } else {
7256                    self.range.start = chunk_end;
7257                    self.buffer_chunk.take()
7258                }
7259            }
7260            DiffTransform::DeletedHunk {
7261                buffer_id,
7262                base_text_byte_range,
7263                has_trailing_newline,
7264                ..
7265            } => {
7266                let base_text_start =
7267                    base_text_byte_range.start + self.range.start - diff_transform_start;
7268                let base_text_end =
7269                    base_text_byte_range.start + self.range.end - diff_transform_start;
7270                let base_text_end = base_text_end.min(base_text_byte_range.end);
7271
7272                let mut chunks = if let Some((_, mut chunks)) = self
7273                    .diff_base_chunks
7274                    .take()
7275                    .filter(|(id, _)| id == buffer_id)
7276                {
7277                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7278                    {
7279                        chunks.seek(base_text_start..base_text_end);
7280                    }
7281                    chunks
7282                } else {
7283                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text()?;
7284                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7285                };
7286
7287                let chunk = if let Some(chunk) = chunks.next() {
7288                    self.range.start += chunk.text.len();
7289                    self.diff_base_chunks = Some((*buffer_id, chunks));
7290                    chunk
7291                } else {
7292                    debug_assert!(has_trailing_newline);
7293                    self.range.start += "\n".len();
7294                    Chunk {
7295                        text: "\n",
7296                        ..Default::default()
7297                    }
7298                };
7299                Some(chunk)
7300            }
7301        }
7302    }
7303}
7304
7305impl<'a> MultiBufferBytes<'a> {
7306    fn consume(&mut self, len: usize) {
7307        self.range.start += len;
7308        self.chunk = &self.chunk[len..];
7309
7310        if !self.range.is_empty() && self.chunk.is_empty() {
7311            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7312                self.chunk = chunk;
7313            } else if self.has_trailing_newline {
7314                self.has_trailing_newline = false;
7315                self.chunk = b"\n";
7316            } else {
7317                self.cursor.next();
7318                if let Some(region) = self.cursor.region() {
7319                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7320                        region.buffer_range.start
7321                            ..(region.buffer_range.start + self.range.end - region.range.start)
7322                                .min(region.buffer_range.end),
7323                    );
7324                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7325                    self.excerpt_bytes = Some(excerpt_bytes);
7326                    self.has_trailing_newline =
7327                        region.has_trailing_newline && self.range.end >= region.range.end;
7328                    if self.chunk.is_empty() && self.has_trailing_newline {
7329                        self.has_trailing_newline = false;
7330                        self.chunk = b"\n";
7331                    }
7332                }
7333            }
7334        }
7335    }
7336}
7337
7338impl<'a> Iterator for MultiBufferBytes<'a> {
7339    type Item = &'a [u8];
7340
7341    fn next(&mut self) -> Option<Self::Item> {
7342        let chunk = self.chunk;
7343        if chunk.is_empty() {
7344            None
7345        } else {
7346            self.consume(chunk.len());
7347            Some(chunk)
7348        }
7349    }
7350}
7351
7352impl<'a> io::Read for MultiBufferBytes<'a> {
7353    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7354        let len = cmp::min(buf.len(), self.chunk.len());
7355        buf[..len].copy_from_slice(&self.chunk[..len]);
7356        if len > 0 {
7357            self.consume(len);
7358        }
7359        Ok(len)
7360    }
7361}
7362
7363impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
7364    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7365        let len = cmp::min(buf.len(), self.chunk.len());
7366        buf[..len].copy_from_slice(&self.chunk[..len]);
7367        buf[..len].reverse();
7368        if len > 0 {
7369            self.range.end -= len;
7370            self.chunk = &self.chunk[..self.chunk.len() - len];
7371            if !self.range.is_empty() && self.chunk.is_empty() {
7372                if let Some(chunk) = self.chunks.next() {
7373                    self.chunk = chunk.as_bytes();
7374                }
7375            }
7376        }
7377        Ok(len)
7378    }
7379}
7380
7381impl<'a> Iterator for ExcerptChunks<'a> {
7382    type Item = Chunk<'a>;
7383
7384    fn next(&mut self) -> Option<Self::Item> {
7385        if let Some(chunk) = self.content_chunks.next() {
7386            return Some(chunk);
7387        }
7388
7389        if self.footer_height > 0 {
7390            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7391            self.footer_height = 0;
7392            return Some(Chunk {
7393                text,
7394                ..Default::default()
7395            });
7396        }
7397
7398        None
7399    }
7400}
7401
7402impl ToOffset for Point {
7403    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7404        snapshot.point_to_offset(*self)
7405    }
7406}
7407
7408impl ToOffset for usize {
7409    #[track_caller]
7410    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7411        assert!(*self <= snapshot.len(), "offset is out of range");
7412        *self
7413    }
7414}
7415
7416impl ToOffset for OffsetUtf16 {
7417    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7418        snapshot.offset_utf16_to_offset(*self)
7419    }
7420}
7421
7422impl ToOffset for PointUtf16 {
7423    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7424        snapshot.point_utf16_to_offset(*self)
7425    }
7426}
7427
7428impl ToOffsetUtf16 for OffsetUtf16 {
7429    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7430        *self
7431    }
7432}
7433
7434impl ToOffsetUtf16 for usize {
7435    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7436        snapshot.offset_to_offset_utf16(*self)
7437    }
7438}
7439
7440impl ToPoint for usize {
7441    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7442        snapshot.offset_to_point(*self)
7443    }
7444}
7445
7446impl ToPoint for Point {
7447    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7448        *self
7449    }
7450}
7451
7452impl ToPointUtf16 for usize {
7453    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7454        snapshot.offset_to_point_utf16(*self)
7455    }
7456}
7457
7458impl ToPointUtf16 for Point {
7459    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7460        snapshot.point_to_point_utf16(*self)
7461    }
7462}
7463
7464impl ToPointUtf16 for PointUtf16 {
7465    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7466        *self
7467    }
7468}
7469
7470impl From<ExcerptId> for EntityId {
7471    fn from(id: ExcerptId) -> Self {
7472        EntityId::from(id.0 as u64)
7473    }
7474}
7475
7476pub fn build_excerpt_ranges<T>(
7477    buffer: &BufferSnapshot,
7478    ranges: &[Range<T>],
7479    context_line_count: u32,
7480) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7481where
7482    T: text::ToPoint,
7483{
7484    let max_point = buffer.max_point();
7485    let mut range_counts = Vec::new();
7486    let mut excerpt_ranges = Vec::new();
7487    let mut range_iter = ranges
7488        .iter()
7489        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7490        .peekable();
7491    while let Some(range) = range_iter.next() {
7492        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7493        let row = (range.end.row + context_line_count).min(max_point.row);
7494        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7495
7496        let mut ranges_in_excerpt = 1;
7497
7498        while let Some(next_range) = range_iter.peek() {
7499            if next_range.start.row <= excerpt_end.row + context_line_count {
7500                let row = (next_range.end.row + context_line_count).min(max_point.row);
7501                excerpt_end = Point::new(row, buffer.line_len(row));
7502
7503                ranges_in_excerpt += 1;
7504                range_iter.next();
7505            } else {
7506                break;
7507            }
7508        }
7509
7510        excerpt_ranges.push(ExcerptRange {
7511            context: excerpt_start..excerpt_end,
7512            primary: Some(range),
7513        });
7514        range_counts.push(ranges_in_excerpt);
7515    }
7516
7517    (excerpt_ranges, range_counts)
7518}