multi_buffer.rs

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