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