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