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 diff = self.diffs.get(&buffer.remote_id())?;
3527            let buffer_start = buffer.anchor_before(buffer_range.start);
3528            let buffer_end = buffer.anchor_after(buffer_range.end);
3529            Some(
3530                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3531                    .filter_map(|hunk| {
3532                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3533                            return None;
3534                        }
3535                        Some((hunk.range.clone(), hunk))
3536                    }),
3537            )
3538        })
3539        .filter_map(move |(range, hunk, excerpt)| {
3540            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3541            {
3542                return None;
3543            }
3544            let end_row = if range.end.column == 0 {
3545                range.end.row
3546            } else {
3547                range.end.row + 1
3548            };
3549            Some(MultiBufferDiffHunk {
3550                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3551                buffer_id: excerpt.buffer_id,
3552                excerpt_id: excerpt.id,
3553                buffer_range: hunk.buffer_range.clone(),
3554                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3555                secondary_status: hunk.secondary_status,
3556            })
3557        })
3558    }
3559
3560    pub fn excerpt_ids_for_range<T: ToOffset>(
3561        &self,
3562        range: Range<T>,
3563    ) -> impl Iterator<Item = ExcerptId> + '_ {
3564        let range = range.start.to_offset(self)..range.end.to_offset(self);
3565        let mut cursor = self.cursor::<usize>();
3566        cursor.seek(&range.start);
3567        std::iter::from_fn(move || {
3568            let region = cursor.region()?;
3569            if region.range.start >= range.end {
3570                return None;
3571            }
3572            cursor.next_excerpt();
3573            Some(region.excerpt.id)
3574        })
3575    }
3576
3577    pub fn buffer_ids_for_range<T: ToOffset>(
3578        &self,
3579        range: Range<T>,
3580    ) -> impl Iterator<Item = BufferId> + '_ {
3581        let range = range.start.to_offset(self)..range.end.to_offset(self);
3582        let mut cursor = self.cursor::<usize>();
3583        cursor.seek(&range.start);
3584        std::iter::from_fn(move || {
3585            let region = cursor.region()?;
3586            if region.range.start > range.end
3587                || region.range.start == range.end && region.range.start > range.start
3588            {
3589                return None;
3590            }
3591            cursor.next_excerpt();
3592            Some(region.excerpt.buffer_id)
3593        })
3594    }
3595
3596    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3597        &self,
3598        ranges: impl Iterator<Item = Range<T>>,
3599    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3600        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3601    }
3602
3603    pub fn range_to_buffer_ranges<T: ToOffset>(
3604        &self,
3605        range: Range<T>,
3606    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3607        let start = range.start.to_offset(&self);
3608        let end = range.end.to_offset(&self);
3609
3610        let mut cursor = self.cursor::<usize>();
3611        cursor.seek(&start);
3612
3613        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3614        while let Some(region) = cursor.region() {
3615            if region.range.start > end {
3616                break;
3617            }
3618            if region.is_main_buffer {
3619                let start_overshoot = start.saturating_sub(region.range.start);
3620                let end_overshoot = end.saturating_sub(region.range.start);
3621                let start = region
3622                    .buffer_range
3623                    .end
3624                    .min(region.buffer_range.start + start_overshoot);
3625                let end = region
3626                    .buffer_range
3627                    .end
3628                    .min(region.buffer_range.start + end_overshoot);
3629                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3630                    *excerpt_id == region.excerpt.id && prev_range.end == start
3631                }) {
3632                    prev.1.end = end;
3633                } else {
3634                    result.push((region.buffer, start..end, region.excerpt.id));
3635                }
3636            }
3637            cursor.next();
3638        }
3639        result
3640    }
3641
3642    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3643        &self,
3644        range: Range<T>,
3645    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3646        let start = range.start.to_offset(&self);
3647        let end = range.end.to_offset(&self);
3648
3649        let mut cursor = self.cursor::<usize>();
3650        cursor.seek(&start);
3651
3652        std::iter::from_fn(move || {
3653            let region = cursor.region()?;
3654            if region.range.start > end {
3655                return None;
3656            }
3657            let start_overshoot = start.saturating_sub(region.range.start);
3658            let end_overshoot = end.saturating_sub(region.range.start);
3659            let start = region
3660                .buffer_range
3661                .end
3662                .min(region.buffer_range.start + start_overshoot);
3663            let end = region
3664                .buffer_range
3665                .end
3666                .min(region.buffer_range.start + end_overshoot);
3667
3668            let region_excerpt_id = region.excerpt.id;
3669            let deleted_hunk_anchor = if region.is_main_buffer {
3670                None
3671            } else {
3672                Some(self.anchor_before(region.range.start))
3673            };
3674            let result = (
3675                region.buffer,
3676                start..end,
3677                region_excerpt_id,
3678                deleted_hunk_anchor,
3679            );
3680            cursor.next();
3681            Some(result)
3682        })
3683    }
3684
3685    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3686    /// coordinates.
3687    ///
3688    /// The given callback will be called for every excerpt intersecting the given range. It will
3689    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3690    /// The callback should return an iterator of metadata items from that buffer, each paired
3691    /// with a buffer range.
3692    ///
3693    /// The returned iterator yields each of these metadata items, paired with its range in
3694    /// multi-buffer coordinates.
3695    fn lift_buffer_metadata<'a, D, M, I>(
3696        &'a self,
3697        query_range: Range<D>,
3698        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3699    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3700    where
3701        I: Iterator<Item = (Range<D>, M)> + 'a,
3702        D: TextDimension + Ord + Sub<D, Output = D>,
3703    {
3704        let max_position = D::from_text_summary(&self.text_summary());
3705        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3706        let mut cursor = self.cursor::<D>();
3707
3708        // Find the excerpt and buffer offset where the given range ends.
3709        cursor.seek(&query_range.end);
3710        let mut range_end = None;
3711        while let Some(region) = cursor.region() {
3712            if region.is_main_buffer {
3713                let mut buffer_end = region.buffer_range.start;
3714                let overshoot = if query_range.end > region.range.start {
3715                    query_range.end - region.range.start
3716                } else {
3717                    D::default()
3718                };
3719                buffer_end.add_assign(&overshoot);
3720                range_end = Some((region.excerpt.id, buffer_end));
3721                break;
3722            }
3723            cursor.next();
3724        }
3725
3726        cursor.seek(&query_range.start);
3727
3728        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3729            if region.range.start > D::zero(&()) {
3730                cursor.prev()
3731            }
3732        }
3733
3734        iter::from_fn(move || loop {
3735            let excerpt = cursor.excerpt()?;
3736
3737            // If we have already retrieved metadata for this excerpt, continue to use it.
3738            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3739                .as_mut()
3740                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3741            {
3742                Some(metadata)
3743            }
3744            // Otherwise, compute the intersection of the input range with the excerpt's range,
3745            // and retrieve the metadata for the resulting range.
3746            else {
3747                let region = cursor.region()?;
3748                let mut buffer_start;
3749                if region.is_main_buffer {
3750                    buffer_start = region.buffer_range.start;
3751                    if query_range.start > region.range.start {
3752                        let overshoot = query_range.start - region.range.start;
3753                        buffer_start.add_assign(&overshoot);
3754                    }
3755                    buffer_start = buffer_start.min(region.buffer_range.end);
3756                } else {
3757                    buffer_start = cursor.main_buffer_position()?;
3758                };
3759                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3760                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3761                    if excerpt.id == end_excerpt_id {
3762                        buffer_end = buffer_end.min(end_buffer_offset);
3763                    }
3764                }
3765
3766                if let Some(iterator) =
3767                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3768                {
3769                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3770                } else {
3771                    None
3772                }
3773            };
3774
3775            // Visit each metadata item.
3776            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3777            {
3778                // Find the multibuffer regions that contain the start and end of
3779                // the metadata item's range.
3780                if metadata_buffer_range.start > D::default() {
3781                    while let Some(region) = cursor.region() {
3782                        if region.is_main_buffer
3783                            && (region.buffer_range.end >= metadata_buffer_range.start
3784                                || cursor.is_at_end_of_excerpt())
3785                        {
3786                            break;
3787                        }
3788                        cursor.next();
3789                    }
3790                }
3791                let start_region = cursor.region()?;
3792                while let Some(region) = cursor.region() {
3793                    if region.is_main_buffer
3794                        && (region.buffer_range.end > metadata_buffer_range.end
3795                            || cursor.is_at_end_of_excerpt())
3796                    {
3797                        break;
3798                    }
3799                    cursor.next();
3800                }
3801                let end_region = cursor.region();
3802
3803                // Convert the metadata item's range into multibuffer coordinates.
3804                let mut start_position = start_region.range.start;
3805                let region_buffer_start = start_region.buffer_range.start;
3806                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3807                {
3808                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3809                    start_position = start_position.min(start_region.range.end);
3810                }
3811
3812                let mut end_position = max_position;
3813                if let Some(end_region) = &end_region {
3814                    end_position = end_region.range.start;
3815                    debug_assert!(end_region.is_main_buffer);
3816                    let region_buffer_start = end_region.buffer_range.start;
3817                    if metadata_buffer_range.end > region_buffer_start {
3818                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3819                    }
3820                    end_position = end_position.min(end_region.range.end);
3821                }
3822
3823                if start_position <= query_range.end && end_position >= query_range.start {
3824                    return Some((start_position..end_position, metadata, excerpt));
3825                }
3826            }
3827            // When there are no more metadata items for this excerpt, move to the next excerpt.
3828            else {
3829                current_excerpt_metadata.take();
3830                if let Some((end_excerpt_id, _)) = range_end {
3831                    if excerpt.id == end_excerpt_id {
3832                        return None;
3833                    }
3834                }
3835                cursor.next_excerpt();
3836            }
3837        })
3838    }
3839
3840    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3841        let offset = position.to_offset(self);
3842
3843        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3844        cursor.seek(&DimensionPair {
3845            key: offset,
3846            value: None,
3847        });
3848        cursor.seek_to_start_of_current_excerpt();
3849        let excerpt = cursor.excerpt()?;
3850
3851        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3852        let current_position = self
3853            .anchor_before(offset)
3854            .text_anchor
3855            .to_offset(&excerpt.buffer);
3856        let excerpt_end = excerpt
3857            .buffer
3858            .anchor_before(excerpt_end.min(current_position));
3859
3860        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3861            for hunk in diff.hunks_intersecting_range_rev(
3862                excerpt.range.context.start..excerpt_end,
3863                &excerpt.buffer,
3864            ) {
3865                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3866                if hunk_end >= current_position {
3867                    continue;
3868                }
3869                let start =
3870                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3871                        .to_point(&self);
3872                return Some(MultiBufferRow(start.row));
3873            }
3874        }
3875
3876        loop {
3877            cursor.prev_excerpt();
3878            let excerpt = cursor.excerpt()?;
3879
3880            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3881                continue;
3882            };
3883            let mut hunks =
3884                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3885            let Some(hunk) = hunks.next() else {
3886                continue;
3887            };
3888            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3889                .to_point(&self);
3890            return Some(MultiBufferRow(start.row));
3891        }
3892    }
3893
3894    pub fn has_diff_hunks(&self) -> bool {
3895        self.diffs.values().any(|diff| !diff.is_empty())
3896    }
3897
3898    pub fn surrounding_word<T: ToOffset>(
3899        &self,
3900        start: T,
3901        for_completion: bool,
3902    ) -> (Range<usize>, Option<CharKind>) {
3903        let mut start = start.to_offset(self);
3904        let mut end = start;
3905        let mut next_chars = self.chars_at(start).peekable();
3906        let mut prev_chars = self.reversed_chars_at(start).peekable();
3907
3908        let classifier = self
3909            .char_classifier_at(start)
3910            .for_completion(for_completion);
3911
3912        let word_kind = cmp::max(
3913            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3914            next_chars.peek().copied().map(|c| classifier.kind(c)),
3915        );
3916
3917        for ch in prev_chars {
3918            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3919                start -= ch.len_utf8();
3920            } else {
3921                break;
3922            }
3923        }
3924
3925        for ch in next_chars {
3926            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3927                end += ch.len_utf8();
3928            } else {
3929                break;
3930            }
3931        }
3932
3933        (start..end, word_kind)
3934    }
3935
3936    pub fn is_singleton(&self) -> bool {
3937        self.singleton
3938    }
3939
3940    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3941        if self.singleton {
3942            self.excerpts
3943                .iter()
3944                .next()
3945                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3946        } else {
3947            None
3948        }
3949    }
3950
3951    pub fn len(&self) -> usize {
3952        self.diff_transforms.summary().output.len
3953    }
3954
3955    pub fn is_empty(&self) -> bool {
3956        self.excerpts.summary().text.len == 0
3957    }
3958
3959    pub fn widest_line_number(&self) -> u32 {
3960        self.excerpts.summary().widest_line_number + 1
3961    }
3962
3963    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3964        let range = range.start.to_offset(self)..range.end.to_offset(self);
3965        let mut excerpts = self.cursor::<usize>();
3966        excerpts.seek(&range.start);
3967
3968        let mut chunk;
3969        let mut has_trailing_newline;
3970        let excerpt_bytes;
3971        if let Some(region) = excerpts.region() {
3972            let mut bytes = region.buffer.bytes_in_range(
3973                region.buffer_range.start + range.start - region.range.start
3974                    ..(region.buffer_range.start + range.end - region.range.start)
3975                        .min(region.buffer_range.end),
3976            );
3977            chunk = bytes.next().unwrap_or(&[][..]);
3978            excerpt_bytes = Some(bytes);
3979            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3980            if chunk.is_empty() && has_trailing_newline {
3981                chunk = b"\n";
3982                has_trailing_newline = false;
3983            }
3984        } else {
3985            chunk = &[][..];
3986            excerpt_bytes = None;
3987            has_trailing_newline = false;
3988        };
3989
3990        MultiBufferBytes {
3991            range,
3992            cursor: excerpts,
3993            excerpt_bytes,
3994            has_trailing_newline,
3995            chunk,
3996        }
3997    }
3998
3999    pub fn reversed_bytes_in_range<T: ToOffset>(
4000        &self,
4001        range: Range<T>,
4002    ) -> ReversedMultiBufferBytes {
4003        let range = range.start.to_offset(self)..range.end.to_offset(self);
4004        let mut chunks = self.reversed_chunks_in_range(range.clone());
4005        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4006        ReversedMultiBufferBytes {
4007            range,
4008            chunks,
4009            chunk,
4010        }
4011    }
4012
4013    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4014        let mut cursor = self.cursor::<Point>();
4015        cursor.seek(&Point::new(start_row.0, 0));
4016        let mut result = MultiBufferRows {
4017            point: Point::new(0, 0),
4018            is_empty: self.excerpts.is_empty(),
4019            cursor,
4020        };
4021        result.seek(start_row);
4022        result
4023    }
4024
4025    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4026        let mut chunks = MultiBufferChunks {
4027            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4028            range: 0..0,
4029            excerpts: self.excerpts.cursor(&()),
4030            diff_transforms: self.diff_transforms.cursor(&()),
4031            diffs: &self.diffs,
4032            diff_base_chunks: None,
4033            excerpt_chunks: None,
4034            buffer_chunk: None,
4035            language_aware,
4036        };
4037        let range = range.start.to_offset(self)..range.end.to_offset(self);
4038        chunks.seek(range);
4039        chunks
4040    }
4041
4042    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4043        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4044    }
4045
4046    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4047        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4048    }
4049
4050    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4051        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4052    }
4053
4054    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4055        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4056            buffer.clip_point_utf16(Unclipped(point), bias)
4057        })
4058    }
4059
4060    pub fn offset_to_point(&self, offset: usize) -> Point {
4061        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4062    }
4063
4064    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4065        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4066    }
4067
4068    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4069        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4070    }
4071
4072    pub fn point_to_offset(&self, point: Point) -> usize {
4073        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4074    }
4075
4076    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4077        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4078    }
4079
4080    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4081        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4082    }
4083
4084    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4085        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4086    }
4087
4088    fn clip_dimension<D>(
4089        &self,
4090        position: D,
4091        bias: Bias,
4092        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4093    ) -> D
4094    where
4095        D: TextDimension + Ord + Sub<D, Output = D>,
4096    {
4097        let mut cursor = self.cursor();
4098        cursor.seek(&position);
4099        if let Some(region) = cursor.region() {
4100            if position >= region.range.end {
4101                return region.range.end;
4102            }
4103            let overshoot = position - region.range.start;
4104            let mut buffer_position = region.buffer_range.start;
4105            buffer_position.add_assign(&overshoot);
4106            let clipped_buffer_position =
4107                clip_buffer_position(&region.buffer, buffer_position, bias);
4108            let mut position = region.range.start;
4109            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4110            position
4111        } else {
4112            D::from_text_summary(&self.text_summary())
4113        }
4114    }
4115
4116    fn convert_dimension<D1, D2>(
4117        &self,
4118        key: D1,
4119        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4120    ) -> D2
4121    where
4122        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4123        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4124    {
4125        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4126        cursor.seek(&DimensionPair { key, value: None });
4127        if let Some(region) = cursor.region() {
4128            if key >= region.range.end.key {
4129                return region.range.end.value.unwrap();
4130            }
4131            let start_key = region.range.start.key;
4132            let start_value = region.range.start.value.unwrap();
4133            let buffer_start_key = region.buffer_range.start.key;
4134            let buffer_start_value = region.buffer_range.start.value.unwrap();
4135            let mut buffer_key = buffer_start_key;
4136            buffer_key.add_assign(&(key - start_key));
4137            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4138            let mut result = start_value;
4139            result.add_assign(&(buffer_value - buffer_start_value));
4140            result
4141        } else {
4142            D2::from_text_summary(&self.text_summary())
4143        }
4144    }
4145
4146    pub fn point_to_buffer_offset<T: ToOffset>(
4147        &self,
4148        point: T,
4149    ) -> Option<(&BufferSnapshot, usize)> {
4150        let offset = point.to_offset(self);
4151        let mut cursor = self.cursor::<usize>();
4152        cursor.seek(&offset);
4153        let region = cursor.region()?;
4154        let overshoot = offset - region.range.start;
4155        let buffer_offset = region.buffer_range.start + overshoot;
4156        Some((region.buffer, buffer_offset))
4157    }
4158
4159    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4160        let mut cursor = self.cursor::<Point>();
4161        cursor.seek(&point);
4162        let region = cursor.region()?;
4163        let overshoot = point - region.range.start;
4164        let buffer_offset = region.buffer_range.start + overshoot;
4165        Some((region.buffer, buffer_offset, region.is_main_buffer))
4166    }
4167
4168    pub fn suggested_indents(
4169        &self,
4170        rows: impl IntoIterator<Item = u32>,
4171        cx: &App,
4172    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4173        let mut result = BTreeMap::new();
4174
4175        let mut rows_for_excerpt = Vec::new();
4176        let mut cursor = self.cursor::<Point>();
4177        let mut rows = rows.into_iter().peekable();
4178        let mut prev_row = u32::MAX;
4179        let mut prev_language_indent_size = IndentSize::default();
4180
4181        while let Some(row) = rows.next() {
4182            cursor.seek(&Point::new(row, 0));
4183            let Some(region) = cursor.region() else {
4184                continue;
4185            };
4186
4187            // Retrieve the language and indent size once for each disjoint region being indented.
4188            let single_indent_size = if row.saturating_sub(1) == prev_row {
4189                prev_language_indent_size
4190            } else {
4191                region
4192                    .buffer
4193                    .language_indent_size_at(Point::new(row, 0), cx)
4194            };
4195            prev_language_indent_size = single_indent_size;
4196            prev_row = row;
4197
4198            let start_buffer_row = region.buffer_range.start.row;
4199            let start_multibuffer_row = region.range.start.row;
4200            let end_multibuffer_row = region.range.end.row;
4201
4202            rows_for_excerpt.push(row);
4203            while let Some(next_row) = rows.peek().copied() {
4204                if end_multibuffer_row > next_row {
4205                    rows_for_excerpt.push(next_row);
4206                    rows.next();
4207                } else {
4208                    break;
4209                }
4210            }
4211
4212            let buffer_rows = rows_for_excerpt
4213                .drain(..)
4214                .map(|row| start_buffer_row + row - start_multibuffer_row);
4215            let buffer_indents = region
4216                .buffer
4217                .suggested_indents(buffer_rows, single_indent_size);
4218            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4219                (
4220                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4221                    indent,
4222                )
4223            });
4224            result.extend(multibuffer_indents);
4225        }
4226
4227        result
4228    }
4229
4230    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4231        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4232            let mut size = buffer.indent_size_for_line(range.start.row);
4233            size.len = size
4234                .len
4235                .min(range.end.column)
4236                .saturating_sub(range.start.column);
4237            size
4238        } else {
4239            IndentSize::spaces(0)
4240        }
4241    }
4242
4243    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4244        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4245            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4246        } else {
4247            LineIndent::spaces(0)
4248        }
4249    }
4250
4251    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4252        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4253
4254        if self.language_settings(cx).extend_comment_on_newline {
4255            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4256                let delimiters = language_scope.line_comment_prefixes();
4257                for delimiter in delimiters {
4258                    if *self
4259                        .chars_at(Point::new(row.0, indent.len() as u32))
4260                        .take(delimiter.chars().count())
4261                        .collect::<String>()
4262                        .as_str()
4263                        == **delimiter
4264                    {
4265                        indent.push_str(&delimiter);
4266                        break;
4267                    }
4268                }
4269            }
4270        }
4271
4272        indent
4273    }
4274
4275    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4276    where
4277        T: ToOffset,
4278    {
4279        for char in self.reversed_chars_at(position) {
4280            if !char.is_whitespace() {
4281                return false;
4282            }
4283            if char == '\n' {
4284                return true;
4285            }
4286        }
4287        return true;
4288    }
4289
4290    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4291        while row.0 > 0 {
4292            row.0 -= 1;
4293            if !self.is_line_blank(row) {
4294                return Some(row);
4295            }
4296        }
4297        None
4298    }
4299
4300    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4301        if let Some((_, range)) = self.buffer_line_for_row(row) {
4302            range.end.column - range.start.column
4303        } else {
4304            0
4305        }
4306    }
4307
4308    pub fn buffer_line_for_row(
4309        &self,
4310        row: MultiBufferRow,
4311    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4312        let mut cursor = self.cursor::<Point>();
4313        let point = Point::new(row.0, 0);
4314        cursor.seek(&point);
4315        let region = cursor.region()?;
4316        let overshoot = point.min(region.range.end) - region.range.start;
4317        let buffer_point = region.buffer_range.start + overshoot;
4318        if buffer_point.row > region.buffer_range.end.row {
4319            return None;
4320        }
4321        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4322        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4323            .min(region.buffer_range.end);
4324        Some((region.buffer, line_start..line_end))
4325    }
4326
4327    pub fn max_point(&self) -> Point {
4328        self.text_summary().lines
4329    }
4330
4331    pub fn max_row(&self) -> MultiBufferRow {
4332        MultiBufferRow(self.text_summary().lines.row)
4333    }
4334
4335    pub fn text_summary(&self) -> TextSummary {
4336        self.diff_transforms.summary().output
4337    }
4338
4339    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4340    where
4341        D: TextDimension,
4342        O: ToOffset,
4343    {
4344        let range = range.start.to_offset(self)..range.end.to_offset(self);
4345        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4346        cursor.seek(&range.start, Bias::Right, &());
4347
4348        let Some(first_transform) = cursor.item() else {
4349            return D::from_text_summary(&TextSummary::default());
4350        };
4351
4352        let diff_transform_start = cursor.start().0;
4353        let diff_transform_end = cursor.end(&()).0;
4354        let diff_start = range.start;
4355        let start_overshoot = diff_start - diff_transform_start;
4356        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4357
4358        let mut result = match first_transform {
4359            DiffTransform::BufferContent { .. } => {
4360                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4361                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4362                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4363            }
4364            DiffTransform::DeletedHunk {
4365                buffer_id,
4366                base_text_byte_range,
4367                has_trailing_newline,
4368                ..
4369            } => {
4370                let buffer_start = base_text_byte_range.start + start_overshoot;
4371                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4372                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4373                    panic!("{:?} is in non-existent deleted hunk", range.start)
4374                };
4375
4376                let include_trailing_newline =
4377                    *has_trailing_newline && range.end >= diff_transform_end;
4378                if include_trailing_newline {
4379                    buffer_end -= 1;
4380                }
4381
4382                let mut summary =
4383                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4384
4385                if include_trailing_newline {
4386                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4387                }
4388
4389                summary
4390            }
4391        };
4392        if range.end < diff_transform_end {
4393            return result;
4394        }
4395
4396        cursor.next(&());
4397        result.add_assign(&D::from_text_summary(&cursor.summary(
4398            &range.end,
4399            Bias::Right,
4400            &(),
4401        )));
4402
4403        let Some(last_transform) = cursor.item() else {
4404            return result;
4405        };
4406
4407        let overshoot = range.end - cursor.start().0;
4408        let suffix = match last_transform {
4409            DiffTransform::BufferContent { .. } => {
4410                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4411                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4412            }
4413            DiffTransform::DeletedHunk {
4414                base_text_byte_range,
4415                buffer_id,
4416                has_trailing_newline,
4417                ..
4418            } => {
4419                let buffer_end = base_text_byte_range.start + overshoot;
4420                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4421                    panic!("{:?} is in non-existent deleted hunk", range.end)
4422                };
4423
4424                let mut suffix = base_text
4425                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4426                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4427                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4428                }
4429                suffix
4430            }
4431        };
4432
4433        result.add_assign(&suffix);
4434        result
4435    }
4436
4437    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4438    where
4439        D: TextDimension,
4440    {
4441        // let mut range = range.start..range.end;
4442        let mut summary = D::zero(&());
4443        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4444        cursor.seek(&range.start, Bias::Right, &());
4445        if let Some(excerpt) = cursor.item() {
4446            let mut end_before_newline = cursor.end(&());
4447            if excerpt.has_trailing_newline {
4448                end_before_newline -= ExcerptOffset::new(1);
4449            }
4450
4451            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4452            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4453            let end_in_excerpt =
4454                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4455            summary.add_assign(
4456                &excerpt
4457                    .buffer
4458                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4459            );
4460
4461            if range.end > end_before_newline {
4462                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4463            }
4464
4465            cursor.next(&());
4466        }
4467
4468        if range.end > *cursor.start() {
4469            summary.add_assign(
4470                &cursor
4471                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4472                    .0,
4473            );
4474            if let Some(excerpt) = cursor.item() {
4475                range.end = cmp::max(*cursor.start(), range.end);
4476
4477                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4478                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4479                summary.add_assign(
4480                    &excerpt
4481                        .buffer
4482                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4483                );
4484            }
4485        }
4486
4487        summary
4488    }
4489
4490    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4491    where
4492        D: TextDimension + Ord + Sub<D, Output = D>,
4493    {
4494        self.summaries_for_anchors([anchor])[0]
4495    }
4496
4497    fn resolve_summary_for_anchor<D>(
4498        &self,
4499        anchor: &Anchor,
4500        excerpt_position: D,
4501        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4502    ) -> D
4503    where
4504        D: TextDimension + Ord + Sub<D, Output = D>,
4505    {
4506        loop {
4507            let transform_end_position = diff_transforms.end(&()).0 .0;
4508            let at_transform_end =
4509                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4510            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4511                diff_transforms.next(&());
4512                continue;
4513            }
4514
4515            let mut position = diff_transforms.start().1 .0;
4516            match diff_transforms.item() {
4517                Some(DiffTransform::DeletedHunk {
4518                    buffer_id,
4519                    base_text_byte_range,
4520                    ..
4521                }) => {
4522                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4523                        if let Some(base_text) =
4524                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4525                        {
4526                            if base_text.can_resolve(&diff_base_anchor) {
4527                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4528                                if base_text_offset >= base_text_byte_range.start
4529                                    && base_text_offset <= base_text_byte_range.end
4530                                {
4531                                    let position_in_hunk = base_text
4532                                        .text_summary_for_range::<D, _>(
4533                                            base_text_byte_range.start..base_text_offset,
4534                                        );
4535                                    position.add_assign(&position_in_hunk);
4536                                } else if at_transform_end {
4537                                    diff_transforms.next(&());
4538                                    continue;
4539                                }
4540                            }
4541                        }
4542                    }
4543                }
4544                _ => {
4545                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4546                        diff_transforms.next(&());
4547                        continue;
4548                    }
4549                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4550                    position.add_assign(&overshoot);
4551                }
4552            }
4553
4554            return position;
4555        }
4556    }
4557
4558    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4559        let mut cursor = self
4560            .excerpts
4561            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4562        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4563
4564        cursor.seek(&Some(locator), Bias::Left, &());
4565        if cursor.item().is_none() {
4566            cursor.next(&());
4567        }
4568
4569        let mut position = cursor.start().1;
4570        if let Some(excerpt) = cursor.item() {
4571            if excerpt.id == anchor.excerpt_id {
4572                let excerpt_buffer_start = excerpt
4573                    .buffer
4574                    .offset_for_anchor(&excerpt.range.context.start);
4575                let excerpt_buffer_end =
4576                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4577                let buffer_position = cmp::min(
4578                    excerpt_buffer_end,
4579                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4580                );
4581                if buffer_position > excerpt_buffer_start {
4582                    position.value += buffer_position - excerpt_buffer_start;
4583                }
4584            }
4585        }
4586        position
4587    }
4588
4589    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4590    where
4591        D: TextDimension + Ord + Sub<D, Output = D>,
4592        I: 'a + IntoIterator<Item = &'a Anchor>,
4593    {
4594        let mut anchors = anchors.into_iter().peekable();
4595        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4596        let mut diff_transforms_cursor = self
4597            .diff_transforms
4598            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4599        diff_transforms_cursor.next(&());
4600
4601        let mut summaries = Vec::new();
4602        while let Some(anchor) = anchors.peek() {
4603            let excerpt_id = anchor.excerpt_id;
4604            let excerpt_anchors = iter::from_fn(|| {
4605                let anchor = anchors.peek()?;
4606                if anchor.excerpt_id == excerpt_id {
4607                    Some(anchors.next().unwrap())
4608                } else {
4609                    None
4610                }
4611            });
4612
4613            let locator = self.excerpt_locator_for_id(excerpt_id);
4614            cursor.seek_forward(locator, Bias::Left, &());
4615            if cursor.item().is_none() {
4616                cursor.next(&());
4617            }
4618
4619            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4620            if let Some(excerpt) = cursor.item() {
4621                if excerpt.id != excerpt_id {
4622                    let position = self.resolve_summary_for_anchor(
4623                        &Anchor::min(),
4624                        excerpt_start_position,
4625                        &mut diff_transforms_cursor,
4626                    );
4627                    summaries.extend(excerpt_anchors.map(|_| position));
4628                    continue;
4629                }
4630                let excerpt_buffer_start =
4631                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4632                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4633                for (buffer_summary, anchor) in excerpt
4634                    .buffer
4635                    .summaries_for_anchors_with_payload::<D, _, _>(
4636                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4637                    )
4638                {
4639                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4640                    let mut position = excerpt_start_position;
4641                    if summary > excerpt_buffer_start {
4642                        position.add_assign(&(summary - excerpt_buffer_start));
4643                    }
4644
4645                    if position > diff_transforms_cursor.start().0 .0 {
4646                        diff_transforms_cursor.seek_forward(
4647                            &ExcerptDimension(position),
4648                            Bias::Left,
4649                            &(),
4650                        );
4651                    }
4652
4653                    summaries.push(self.resolve_summary_for_anchor(
4654                        anchor,
4655                        position,
4656                        &mut diff_transforms_cursor,
4657                    ));
4658                }
4659            } else {
4660                diff_transforms_cursor.seek_forward(
4661                    &ExcerptDimension(excerpt_start_position),
4662                    Bias::Left,
4663                    &(),
4664                );
4665                let position = self.resolve_summary_for_anchor(
4666                    &Anchor::max(),
4667                    excerpt_start_position,
4668                    &mut diff_transforms_cursor,
4669                );
4670                summaries.extend(excerpt_anchors.map(|_| position));
4671            }
4672        }
4673
4674        summaries
4675    }
4676
4677    pub fn dimensions_from_points<'a, D>(
4678        &'a self,
4679        points: impl 'a + IntoIterator<Item = Point>,
4680    ) -> impl 'a + Iterator<Item = D>
4681    where
4682        D: TextDimension + Sub<D, Output = D>,
4683    {
4684        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4685        cursor.seek(&DimensionPair {
4686            key: Point::default(),
4687            value: None,
4688        });
4689        let mut points = points.into_iter();
4690        iter::from_fn(move || {
4691            let point = points.next()?;
4692
4693            cursor.seek_forward(&DimensionPair {
4694                key: point,
4695                value: None,
4696            });
4697
4698            if let Some(region) = cursor.region() {
4699                let overshoot = point - region.range.start.key;
4700                let buffer_point = region.buffer_range.start.key + overshoot;
4701                let mut position = region.range.start.value.unwrap();
4702                position.add_assign(
4703                    &region
4704                        .buffer
4705                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4706                );
4707                return Some(position);
4708            } else {
4709                return Some(D::from_text_summary(&self.text_summary()));
4710            }
4711        })
4712    }
4713
4714    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4715    where
4716        I: 'a + IntoIterator<Item = &'a Anchor>,
4717    {
4718        let mut anchors = anchors.into_iter().enumerate().peekable();
4719        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4720        cursor.next(&());
4721
4722        let mut result = Vec::new();
4723
4724        while let Some((_, anchor)) = anchors.peek() {
4725            let old_excerpt_id = anchor.excerpt_id;
4726
4727            // Find the location where this anchor's excerpt should be.
4728            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4729            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4730
4731            if cursor.item().is_none() {
4732                cursor.next(&());
4733            }
4734
4735            let next_excerpt = cursor.item();
4736            let prev_excerpt = cursor.prev_item();
4737
4738            // Process all of the anchors for this excerpt.
4739            while let Some((_, anchor)) = anchors.peek() {
4740                if anchor.excerpt_id != old_excerpt_id {
4741                    break;
4742                }
4743                let (anchor_ix, anchor) = anchors.next().unwrap();
4744                let mut anchor = *anchor;
4745
4746                // Leave min and max anchors unchanged if invalid or
4747                // if the old excerpt still exists at this location
4748                let mut kept_position = next_excerpt
4749                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4750                    || old_excerpt_id == ExcerptId::max()
4751                    || old_excerpt_id == ExcerptId::min();
4752
4753                // If the old excerpt no longer exists at this location, then attempt to
4754                // find an equivalent position for this anchor in an adjacent excerpt.
4755                if !kept_position {
4756                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4757                        if excerpt.contains(&anchor) {
4758                            anchor.excerpt_id = excerpt.id;
4759                            kept_position = true;
4760                            break;
4761                        }
4762                    }
4763                }
4764
4765                // If there's no adjacent excerpt that contains the anchor's position,
4766                // then report that the anchor has lost its position.
4767                if !kept_position {
4768                    anchor = if let Some(excerpt) = next_excerpt {
4769                        let mut text_anchor = excerpt
4770                            .range
4771                            .context
4772                            .start
4773                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4774                        if text_anchor
4775                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4776                            .is_gt()
4777                        {
4778                            text_anchor = excerpt.range.context.end;
4779                        }
4780                        Anchor {
4781                            buffer_id: Some(excerpt.buffer_id),
4782                            excerpt_id: excerpt.id,
4783                            text_anchor,
4784                            diff_base_anchor: None,
4785                        }
4786                    } else if let Some(excerpt) = prev_excerpt {
4787                        let mut text_anchor = excerpt
4788                            .range
4789                            .context
4790                            .end
4791                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4792                        if text_anchor
4793                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4794                            .is_lt()
4795                        {
4796                            text_anchor = excerpt.range.context.start;
4797                        }
4798                        Anchor {
4799                            buffer_id: Some(excerpt.buffer_id),
4800                            excerpt_id: excerpt.id,
4801                            text_anchor,
4802                            diff_base_anchor: None,
4803                        }
4804                    } else if anchor.text_anchor.bias == Bias::Left {
4805                        Anchor::min()
4806                    } else {
4807                        Anchor::max()
4808                    };
4809                }
4810
4811                result.push((anchor_ix, anchor, kept_position));
4812            }
4813        }
4814        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4815        result
4816    }
4817
4818    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4819        self.anchor_at(position, Bias::Left)
4820    }
4821
4822    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4823        self.anchor_at(position, Bias::Right)
4824    }
4825
4826    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4827        let offset = position.to_offset(self);
4828
4829        // Find the given position in the diff transforms. Determine the corresponding
4830        // offset in the excerpts, and whether the position is within a deleted hunk.
4831        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4832        diff_transforms.seek(&offset, Bias::Right, &());
4833
4834        if offset == diff_transforms.start().0 && bias == Bias::Left {
4835            if let Some(prev_item) = diff_transforms.prev_item() {
4836                match prev_item {
4837                    DiffTransform::DeletedHunk { .. } => {
4838                        diff_transforms.prev(&());
4839                    }
4840                    _ => {}
4841                }
4842            }
4843        }
4844        let offset_in_transform = offset - diff_transforms.start().0;
4845        let mut excerpt_offset = diff_transforms.start().1;
4846        let mut diff_base_anchor = None;
4847        if let Some(DiffTransform::DeletedHunk {
4848            buffer_id,
4849            base_text_byte_range,
4850            has_trailing_newline,
4851            ..
4852        }) = diff_transforms.item()
4853        {
4854            let diff = self.diffs.get(buffer_id).expect("missing diff");
4855            if offset_in_transform > base_text_byte_range.len() {
4856                debug_assert!(*has_trailing_newline);
4857                bias = Bias::Right;
4858            } else {
4859                diff_base_anchor = Some(
4860                    diff.base_text()
4861                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4862                );
4863                bias = Bias::Left;
4864            }
4865        } else {
4866            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4867        };
4868
4869        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4870            return Anchor {
4871                buffer_id: Some(buffer_id),
4872                excerpt_id: *excerpt_id,
4873                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4874                diff_base_anchor,
4875            };
4876        }
4877
4878        let mut excerpts = self
4879            .excerpts
4880            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4881        excerpts.seek(&excerpt_offset, Bias::Right, &());
4882        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4883            excerpts.prev(&());
4884        }
4885        if let Some(excerpt) = excerpts.item() {
4886            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4887            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4888                overshoot -= 1;
4889                bias = Bias::Right;
4890            }
4891
4892            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4893            let text_anchor =
4894                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4895            Anchor {
4896                buffer_id: Some(excerpt.buffer_id),
4897                excerpt_id: excerpt.id,
4898                text_anchor,
4899                diff_base_anchor,
4900            }
4901        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4902            Anchor::min()
4903        } else {
4904            Anchor::max()
4905        }
4906    }
4907
4908    /// Returns an anchor for the given excerpt and text anchor,
4909    /// returns None if the excerpt_id is no longer valid.
4910    pub fn anchor_in_excerpt(
4911        &self,
4912        excerpt_id: ExcerptId,
4913        text_anchor: text::Anchor,
4914    ) -> Option<Anchor> {
4915        let locator = self.excerpt_locator_for_id(excerpt_id);
4916        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4917        cursor.seek(locator, Bias::Left, &());
4918        if let Some(excerpt) = cursor.item() {
4919            if excerpt.id == excerpt_id {
4920                let text_anchor = excerpt.clip_anchor(text_anchor);
4921                drop(cursor);
4922                return Some(Anchor {
4923                    buffer_id: Some(excerpt.buffer_id),
4924                    excerpt_id,
4925                    text_anchor,
4926                    diff_base_anchor: None,
4927                });
4928            }
4929        }
4930        None
4931    }
4932
4933    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4934        Some(self.excerpt(excerpt_id)?.range.context.clone())
4935    }
4936
4937    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4938        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4939            true
4940        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4941            excerpt.buffer.can_resolve(&anchor.text_anchor)
4942        } else {
4943            false
4944        }
4945    }
4946
4947    pub fn excerpts(
4948        &self,
4949    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4950        self.excerpts
4951            .iter()
4952            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4953    }
4954
4955    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4956        let excerpts = self.excerpts.cursor(&());
4957        let diff_transforms = self.diff_transforms.cursor(&());
4958        MultiBufferCursor {
4959            excerpts,
4960            diff_transforms,
4961            diffs: &self.diffs,
4962            cached_region: None,
4963        }
4964    }
4965
4966    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4967        let start_locator = self.excerpt_locator_for_id(id);
4968        let mut excerpts = self
4969            .excerpts
4970            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4971        excerpts.seek(&Some(start_locator), Bias::Left, &());
4972        excerpts.prev(&());
4973
4974        let mut diff_transforms = self
4975            .diff_transforms
4976            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4977        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4978        if diff_transforms.end(&()).1 < excerpts.start().1 {
4979            diff_transforms.next(&());
4980        }
4981
4982        let excerpt = excerpts.item()?;
4983        Some(MultiBufferExcerpt {
4984            excerpt,
4985            offset: diff_transforms.start().0 .0,
4986            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4987            excerpt_offset: excerpts.start().1.clone(),
4988            diff_transforms,
4989        })
4990    }
4991
4992    pub fn excerpt_boundaries_in_range<R, T>(
4993        &self,
4994        range: R,
4995    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4996    where
4997        R: RangeBounds<T>,
4998        T: ToOffset,
4999    {
5000        let start_offset;
5001        let start = match range.start_bound() {
5002            Bound::Included(start) => {
5003                start_offset = start.to_offset(self);
5004                Bound::Included(start_offset)
5005            }
5006            Bound::Excluded(_) => {
5007                panic!("not supported")
5008            }
5009            Bound::Unbounded => {
5010                start_offset = 0;
5011                Bound::Unbounded
5012            }
5013        };
5014        let end = match range.end_bound() {
5015            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5016            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5017            Bound::Unbounded => Bound::Unbounded,
5018        };
5019        let bounds = (start, end);
5020
5021        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5022        cursor.seek(&DimensionPair {
5023            key: start_offset,
5024            value: None,
5025        });
5026
5027        if cursor
5028            .region()
5029            .is_some_and(|region| bounds.contains(&region.range.start.key))
5030        {
5031            cursor.prev_excerpt();
5032        } else {
5033            cursor.seek_to_start_of_current_excerpt();
5034        }
5035        let mut prev_region = cursor.region();
5036
5037        cursor.next_excerpt();
5038
5039        let mut visited_end = false;
5040        iter::from_fn(move || loop {
5041            if self.singleton {
5042                return None;
5043            }
5044
5045            let next_region = cursor.region();
5046            cursor.next_excerpt();
5047
5048            let next_region_start = if let Some(region) = &next_region {
5049                if !bounds.contains(&region.range.start.key) {
5050                    prev_region = next_region;
5051                    continue;
5052                }
5053                region.range.start.value.unwrap()
5054            } else {
5055                if !bounds.contains(&self.len()) {
5056                    return None;
5057                }
5058                self.max_point()
5059            };
5060            let next_region_end = if let Some(region) = cursor.region() {
5061                region.range.start.value.unwrap()
5062            } else {
5063                self.max_point()
5064            };
5065
5066            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5067                id: region.excerpt.id,
5068                buffer: region.excerpt.buffer.clone(),
5069                buffer_id: region.excerpt.buffer_id,
5070                range: region.excerpt.range.clone(),
5071                end_row: MultiBufferRow(next_region_start.row),
5072            });
5073
5074            let next = next_region.as_ref().map(|region| ExcerptInfo {
5075                id: region.excerpt.id,
5076                buffer: region.excerpt.buffer.clone(),
5077                buffer_id: region.excerpt.buffer_id,
5078                range: region.excerpt.range.clone(),
5079                end_row: if region.excerpt.has_trailing_newline {
5080                    MultiBufferRow(next_region_end.row - 1)
5081                } else {
5082                    MultiBufferRow(next_region_end.row)
5083                },
5084            });
5085
5086            if next.is_none() {
5087                if visited_end {
5088                    return None;
5089                } else {
5090                    visited_end = true;
5091                }
5092            }
5093
5094            let row = MultiBufferRow(next_region_start.row);
5095
5096            prev_region = next_region;
5097
5098            return Some(ExcerptBoundary { row, prev, next });
5099        })
5100    }
5101
5102    pub fn edit_count(&self) -> usize {
5103        self.edit_count
5104    }
5105
5106    pub fn non_text_state_update_count(&self) -> usize {
5107        self.non_text_state_update_count
5108    }
5109
5110    /// Returns the smallest enclosing bracket ranges containing the given range or
5111    /// None if no brackets contain range or the range is not contained in a single
5112    /// excerpt
5113    ///
5114    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5115    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5116        &self,
5117        range: Range<T>,
5118        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5119    ) -> Option<(Range<usize>, Range<usize>)> {
5120        let range = range.start.to_offset(self)..range.end.to_offset(self);
5121        let mut excerpt = self.excerpt_containing(range.clone())?;
5122        let buffer = excerpt.buffer();
5123        let excerpt_buffer_range = excerpt.buffer_range();
5124
5125        // Filter to ranges contained in the excerpt
5126        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5127            excerpt_buffer_range.contains(&open.start)
5128                && excerpt_buffer_range.contains(&close.end)
5129                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5130        };
5131
5132        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5133            excerpt.map_range_to_buffer(range),
5134            Some(&range_filter),
5135        )?;
5136
5137        Some((
5138            excerpt.map_range_from_buffer(open),
5139            excerpt.map_range_from_buffer(close),
5140        ))
5141    }
5142
5143    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5144    /// not contained in a single excerpt
5145    pub fn enclosing_bracket_ranges<T: ToOffset>(
5146        &self,
5147        range: Range<T>,
5148    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5149        let range = range.start.to_offset(self)..range.end.to_offset(self);
5150        let mut excerpt = self.excerpt_containing(range.clone())?;
5151
5152        Some(
5153            excerpt
5154                .buffer()
5155                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5156                .filter_map(move |pair| {
5157                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5158                        Some((
5159                            excerpt.map_range_from_buffer(pair.open_range),
5160                            excerpt.map_range_from_buffer(pair.close_range),
5161                        ))
5162                    } else {
5163                        None
5164                    }
5165                }),
5166        )
5167    }
5168
5169    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5170    /// not contained in a single excerpt
5171    pub fn text_object_ranges<T: ToOffset>(
5172        &self,
5173        range: Range<T>,
5174        options: TreeSitterOptions,
5175    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5176        let range = range.start.to_offset(self)..range.end.to_offset(self);
5177        self.excerpt_containing(range.clone())
5178            .map(|mut excerpt| {
5179                excerpt
5180                    .buffer()
5181                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5182                    .filter_map(move |(range, text_object)| {
5183                        if excerpt.contains_buffer_range(range.clone()) {
5184                            Some((excerpt.map_range_from_buffer(range), text_object))
5185                        } else {
5186                            None
5187                        }
5188                    })
5189            })
5190            .into_iter()
5191            .flatten()
5192    }
5193
5194    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5195    /// not contained in a single excerpt
5196    pub fn bracket_ranges<T: ToOffset>(
5197        &self,
5198        range: Range<T>,
5199    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5200        let range = range.start.to_offset(self)..range.end.to_offset(self);
5201        let mut excerpt = self.excerpt_containing(range.clone())?;
5202
5203        Some(
5204            excerpt
5205                .buffer()
5206                .bracket_ranges(excerpt.map_range_to_buffer(range))
5207                .filter_map(move |pair| {
5208                    let buffer_range = pair.open_range.start..pair.close_range.end;
5209                    if excerpt.contains_buffer_range(buffer_range) {
5210                        Some((
5211                            excerpt.map_range_from_buffer(pair.open_range),
5212                            excerpt.map_range_from_buffer(pair.close_range),
5213                        ))
5214                    } else {
5215                        None
5216                    }
5217                }),
5218        )
5219    }
5220
5221    pub fn redacted_ranges<'a, T: ToOffset>(
5222        &'a self,
5223        range: Range<T>,
5224        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5225    ) -> impl Iterator<Item = Range<usize>> + 'a {
5226        let range = range.start.to_offset(self)..range.end.to_offset(self);
5227        self.lift_buffer_metadata(range, move |buffer, range| {
5228            if redaction_enabled(buffer.file()) {
5229                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5230            } else {
5231                None
5232            }
5233        })
5234        .map(|(range, _, _)| range)
5235    }
5236
5237    pub fn runnable_ranges(
5238        &self,
5239        range: Range<Anchor>,
5240    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5241        let range = range.start.to_offset(self)..range.end.to_offset(self);
5242        self.lift_buffer_metadata(range, move |buffer, range| {
5243            Some(
5244                buffer
5245                    .runnable_ranges(range.clone())
5246                    .filter(move |runnable| {
5247                        runnable.run_range.start >= range.start
5248                            && runnable.run_range.end < range.end
5249                    })
5250                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5251            )
5252        })
5253        .map(|(run_range, runnable, _)| language::RunnableRange {
5254            run_range,
5255            ..runnable
5256        })
5257    }
5258
5259    pub fn line_indents(
5260        &self,
5261        start_row: MultiBufferRow,
5262        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5263    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5264        let max_point = self.max_point();
5265        let mut cursor = self.cursor::<Point>();
5266        cursor.seek(&Point::new(start_row.0, 0));
5267        iter::from_fn(move || {
5268            let mut region = cursor.region()?;
5269            while !buffer_filter(&region.excerpt.buffer) {
5270                cursor.next();
5271                region = cursor.region()?;
5272            }
5273            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5274            let buffer_start_row =
5275                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5276
5277            let buffer_end_row = if region.is_main_buffer
5278                && (region.has_trailing_newline || region.range.end == max_point)
5279            {
5280                region.buffer_range.end.row
5281            } else {
5282                region.buffer_range.end.row.saturating_sub(1)
5283            };
5284
5285            let line_indents = region
5286                .buffer
5287                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5288            cursor.next();
5289            return Some(line_indents.map(move |(buffer_row, indent)| {
5290                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5291                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5292            }));
5293        })
5294        .flatten()
5295    }
5296
5297    pub fn reversed_line_indents(
5298        &self,
5299        end_row: MultiBufferRow,
5300        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5301    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5302        let max_point = self.max_point();
5303        let mut cursor = self.cursor::<Point>();
5304        cursor.seek(&Point::new(end_row.0, 0));
5305        iter::from_fn(move || {
5306            let mut region = cursor.region()?;
5307            while !buffer_filter(&region.excerpt.buffer) {
5308                cursor.prev();
5309                region = cursor.region()?;
5310            }
5311
5312            let buffer_start_row = region.buffer_range.start.row;
5313            let buffer_end_row = if region.is_main_buffer
5314                && (region.has_trailing_newline || region.range.end == max_point)
5315            {
5316                region.buffer_range.end.row + 1
5317            } else {
5318                region.buffer_range.end.row
5319            };
5320
5321            let overshoot = end_row.0 - region.range.start.row;
5322            let buffer_end_row =
5323                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5324
5325            let line_indents = region
5326                .buffer
5327                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5328            cursor.prev();
5329            return Some(line_indents.map(move |(buffer_row, indent)| {
5330                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5331                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5332            }));
5333        })
5334        .flatten()
5335    }
5336
5337    pub async fn enclosing_indent(
5338        &self,
5339        mut target_row: MultiBufferRow,
5340    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5341        let max_row = MultiBufferRow(self.max_point().row);
5342        if target_row >= max_row {
5343            return None;
5344        }
5345
5346        let mut target_indent = self.line_indent_for_row(target_row);
5347
5348        // If the current row is at the start of an indented block, we want to return this
5349        // block as the enclosing indent.
5350        if !target_indent.is_line_empty() && target_row < max_row {
5351            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5352            if !next_line_indent.is_line_empty()
5353                && target_indent.raw_len() < next_line_indent.raw_len()
5354            {
5355                target_indent = next_line_indent;
5356                target_row.0 += 1;
5357            }
5358        }
5359
5360        const SEARCH_ROW_LIMIT: u32 = 25000;
5361        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5362        const YIELD_INTERVAL: u32 = 100;
5363
5364        let mut accessed_row_counter = 0;
5365
5366        // If there is a blank line at the current row, search for the next non indented lines
5367        if target_indent.is_line_empty() {
5368            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5369            let end =
5370                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5371
5372            let mut non_empty_line_above = None;
5373            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5374                if row < start {
5375                    break;
5376                }
5377                accessed_row_counter += 1;
5378                if accessed_row_counter == YIELD_INTERVAL {
5379                    accessed_row_counter = 0;
5380                    yield_now().await;
5381                }
5382                if !indent.is_line_empty() {
5383                    non_empty_line_above = Some((row, indent));
5384                    break;
5385                }
5386            }
5387
5388            let mut non_empty_line_below = None;
5389            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5390                if row > end {
5391                    break;
5392                }
5393                accessed_row_counter += 1;
5394                if accessed_row_counter == YIELD_INTERVAL {
5395                    accessed_row_counter = 0;
5396                    yield_now().await;
5397                }
5398                if !indent.is_line_empty() {
5399                    non_empty_line_below = Some((row, indent));
5400                    break;
5401                }
5402            }
5403
5404            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5405                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5406                    if above_indent.raw_len() >= below_indent.raw_len() {
5407                        (above_row, above_indent)
5408                    } else {
5409                        (below_row, below_indent)
5410                    }
5411                }
5412                (Some(above), None) => above,
5413                (None, Some(below)) => below,
5414                _ => return None,
5415            };
5416
5417            target_indent = indent;
5418            target_row = row;
5419        }
5420
5421        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5422        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5423
5424        let mut start_indent = None;
5425        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5426            if row < start {
5427                break;
5428            }
5429            accessed_row_counter += 1;
5430            if accessed_row_counter == YIELD_INTERVAL {
5431                accessed_row_counter = 0;
5432                yield_now().await;
5433            }
5434            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5435                start_indent = Some((row, indent));
5436                break;
5437            }
5438        }
5439        let (start_row, start_indent_size) = start_indent?;
5440
5441        let mut end_indent = (end, None);
5442        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5443            if row > end {
5444                break;
5445            }
5446            accessed_row_counter += 1;
5447            if accessed_row_counter == YIELD_INTERVAL {
5448                accessed_row_counter = 0;
5449                yield_now().await;
5450            }
5451            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5452                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5453                break;
5454            }
5455        }
5456        let (end_row, end_indent_size) = end_indent;
5457
5458        let indent = if let Some(end_indent_size) = end_indent_size {
5459            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5460                start_indent_size
5461            } else {
5462                end_indent_size
5463            }
5464        } else {
5465            start_indent_size
5466        };
5467
5468        Some((start_row..end_row, indent))
5469    }
5470
5471    pub fn indent_guides_in_range<T: ToPoint>(
5472        &self,
5473        range: Range<T>,
5474        ignore_disabled_for_language: bool,
5475        cx: &App,
5476    ) -> impl Iterator<Item = IndentGuide> {
5477        let range = range.start.to_point(self)..range.end.to_point(self);
5478        let start_row = MultiBufferRow(range.start.row);
5479        let end_row = MultiBufferRow(range.end.row);
5480
5481        let mut row_indents = self.line_indents(start_row, |buffer| {
5482            let settings =
5483                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5484            settings.indent_guides.enabled || ignore_disabled_for_language
5485        });
5486
5487        let mut result = Vec::new();
5488        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5489
5490        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5491            if first_row > end_row {
5492                break;
5493            }
5494            let current_depth = indent_stack.len() as u32;
5495
5496            let settings =
5497                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5498            let tab_size = settings.tab_size.get() as u32;
5499
5500            // When encountering empty, continue until found useful line indent
5501            // then add to the indent stack with the depth found
5502            let mut found_indent = false;
5503            let mut last_row = first_row;
5504            if line_indent.is_line_empty() {
5505                while !found_indent {
5506                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5507                        break;
5508                    };
5509                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5510                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5511                        break;
5512                    }
5513
5514                    if new_line_indent.is_line_empty() {
5515                        continue;
5516                    }
5517                    last_row = target_row.min(end_row);
5518                    line_indent = new_line_indent;
5519                    found_indent = true;
5520                    break;
5521                }
5522            } else {
5523                found_indent = true
5524            }
5525
5526            let depth = if found_indent {
5527                line_indent.len(tab_size) / tab_size
5528                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5529            } else {
5530                current_depth
5531            };
5532
5533            match depth.cmp(&current_depth) {
5534                cmp::Ordering::Less => {
5535                    for _ in 0..(current_depth - depth) {
5536                        let mut indent = indent_stack.pop().unwrap();
5537                        if last_row != first_row {
5538                            // In this case, we landed on an empty row, had to seek forward,
5539                            // and discovered that the indent we where on is ending.
5540                            // This means that the last display row must
5541                            // be on line that ends this indent range, so we
5542                            // should display the range up to the first non-empty line
5543                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5544                        }
5545
5546                        result.push(indent)
5547                    }
5548                }
5549                cmp::Ordering::Greater => {
5550                    for next_depth in current_depth..depth {
5551                        indent_stack.push(IndentGuide {
5552                            buffer_id: buffer.remote_id(),
5553                            start_row: first_row,
5554                            end_row: last_row,
5555                            depth: next_depth,
5556                            tab_size,
5557                            settings: settings.indent_guides,
5558                        });
5559                    }
5560                }
5561                _ => {}
5562            }
5563
5564            for indent in indent_stack.iter_mut() {
5565                indent.end_row = last_row;
5566            }
5567        }
5568
5569        result.extend(indent_stack);
5570        result.into_iter()
5571    }
5572
5573    pub fn trailing_excerpt_update_count(&self) -> usize {
5574        self.trailing_excerpt_update_count
5575    }
5576
5577    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5578        self.point_to_buffer_offset(point)
5579            .and_then(|(buffer, _)| buffer.file())
5580    }
5581
5582    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5583        self.point_to_buffer_offset(point)
5584            .and_then(|(buffer, offset)| buffer.language_at(offset))
5585    }
5586
5587    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5588        self.excerpts
5589            .first()
5590            .map(|excerpt| &excerpt.buffer)
5591            .map(|buffer| {
5592                language_settings(
5593                    buffer.language().map(|language| language.name()),
5594                    buffer.file(),
5595                    cx,
5596                )
5597            })
5598            .unwrap_or_else(move || self.language_settings_at(0, cx))
5599    }
5600
5601    pub fn language_settings_at<'a, T: ToOffset>(
5602        &'a self,
5603        point: T,
5604        cx: &'a App,
5605    ) -> Cow<'a, LanguageSettings> {
5606        let mut language = None;
5607        let mut file = None;
5608        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5609            language = buffer.language_at(offset);
5610            file = buffer.file();
5611        }
5612        language_settings(language.map(|l| l.name()), file, cx)
5613    }
5614
5615    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5616        self.point_to_buffer_offset(point)
5617            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5618    }
5619
5620    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5621        self.point_to_buffer_offset(point)
5622            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5623            .unwrap_or_default()
5624    }
5625
5626    pub fn language_indent_size_at<T: ToOffset>(
5627        &self,
5628        position: T,
5629        cx: &App,
5630    ) -> Option<IndentSize> {
5631        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5632        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5633    }
5634
5635    pub fn is_dirty(&self) -> bool {
5636        self.is_dirty
5637    }
5638
5639    pub fn has_deleted_file(&self) -> bool {
5640        self.has_deleted_file
5641    }
5642
5643    pub fn has_conflict(&self) -> bool {
5644        self.has_conflict
5645    }
5646
5647    pub fn has_diagnostics(&self) -> bool {
5648        self.excerpts
5649            .iter()
5650            .any(|excerpt| excerpt.buffer.has_diagnostics())
5651    }
5652
5653    pub fn diagnostic_group(
5654        &self,
5655        buffer_id: BufferId,
5656        group_id: usize,
5657    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5658        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5659            if buffer.remote_id() != buffer_id {
5660                return None;
5661            };
5662            Some(
5663                buffer
5664                    .diagnostic_group(group_id)
5665                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5666            )
5667        })
5668        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5669    }
5670
5671    pub fn diagnostics_in_range<'a, T>(
5672        &'a self,
5673        range: Range<T>,
5674    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5675    where
5676        T: 'a
5677            + text::ToOffset
5678            + text::FromAnchor
5679            + TextDimension
5680            + Ord
5681            + Sub<T, Output = T>
5682            + fmt::Debug,
5683    {
5684        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5685            Some(
5686                buffer
5687                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5688                    .map(|entry| (entry.range, entry.diagnostic)),
5689            )
5690        })
5691        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5692    }
5693
5694    pub fn syntax_ancestor<T: ToOffset>(
5695        &self,
5696        range: Range<T>,
5697    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5698        let range = range.start.to_offset(self)..range.end.to_offset(self);
5699        let mut excerpt = self.excerpt_containing(range.clone())?;
5700        let node = excerpt
5701            .buffer()
5702            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5703        let node_range = node.byte_range();
5704        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5705            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5706        } else {
5707            MultiOrSingleBufferOffsetRange::Single(node_range)
5708        };
5709        Some((node, range))
5710    }
5711
5712    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5713        let (excerpt_id, _, buffer) = self.as_singleton()?;
5714        let outline = buffer.outline(theme)?;
5715        Some(Outline::new(
5716            outline
5717                .items
5718                .into_iter()
5719                .flat_map(|item| {
5720                    Some(OutlineItem {
5721                        depth: item.depth,
5722                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5723                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5724                        text: item.text,
5725                        highlight_ranges: item.highlight_ranges,
5726                        name_ranges: item.name_ranges,
5727                        body_range: item.body_range.and_then(|body_range| {
5728                            Some(
5729                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5730                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5731                            )
5732                        }),
5733                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5734                            Some(
5735                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5736                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5737                            )
5738                        }),
5739                    })
5740                })
5741                .collect(),
5742        ))
5743    }
5744
5745    pub fn symbols_containing<T: ToOffset>(
5746        &self,
5747        offset: T,
5748        theme: Option<&SyntaxTheme>,
5749    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5750        let anchor = self.anchor_before(offset);
5751        let excerpt_id = anchor.excerpt_id;
5752        let excerpt = self.excerpt(excerpt_id)?;
5753        Some((
5754            excerpt.buffer_id,
5755            excerpt
5756                .buffer
5757                .symbols_containing(anchor.text_anchor, theme)
5758                .into_iter()
5759                .flatten()
5760                .flat_map(|item| {
5761                    Some(OutlineItem {
5762                        depth: item.depth,
5763                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5764                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5765                        text: item.text,
5766                        highlight_ranges: item.highlight_ranges,
5767                        name_ranges: item.name_ranges,
5768                        body_range: item.body_range.and_then(|body_range| {
5769                            Some(
5770                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5771                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5772                            )
5773                        }),
5774                        annotation_range: item.annotation_range.and_then(|body_range| {
5775                            Some(
5776                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5777                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5778                            )
5779                        }),
5780                    })
5781                })
5782                .collect(),
5783        ))
5784    }
5785
5786    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5787        if id == ExcerptId::min() {
5788            Locator::min_ref()
5789        } else if id == ExcerptId::max() {
5790            Locator::max_ref()
5791        } else {
5792            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5793            cursor.seek(&id, Bias::Left, &());
5794            if let Some(entry) = cursor.item() {
5795                if entry.id == id {
5796                    return &entry.locator;
5797                }
5798            }
5799            panic!("invalid excerpt id {:?}", id)
5800        }
5801    }
5802
5803    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5804    fn excerpt_locators_for_ids(
5805        &self,
5806        ids: impl IntoIterator<Item = ExcerptId>,
5807    ) -> SmallVec<[Locator; 1]> {
5808        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5809        sorted_ids.sort_unstable();
5810        let mut locators = SmallVec::new();
5811
5812        while sorted_ids.last() == Some(&ExcerptId::max()) {
5813            sorted_ids.pop();
5814            if let Some(mapping) = self.excerpt_ids.last() {
5815                locators.push(mapping.locator.clone());
5816            }
5817        }
5818
5819        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5820        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5821            sorted_ids.next();
5822            if let Some(mapping) = self.excerpt_ids.first() {
5823                locators.push(mapping.locator.clone());
5824            }
5825        }
5826
5827        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5828        for id in sorted_ids {
5829            if cursor.seek_forward(&id, Bias::Left, &()) {
5830                locators.push(cursor.item().unwrap().locator.clone());
5831            } else {
5832                panic!("invalid excerpt id {:?}", id);
5833            }
5834        }
5835
5836        locators.sort_unstable();
5837        locators
5838    }
5839
5840    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5841        Some(self.excerpt(excerpt_id)?.buffer_id)
5842    }
5843
5844    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5845        Some(&self.excerpt(excerpt_id)?.buffer)
5846    }
5847
5848    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5849        let mut cursor = self
5850            .excerpts
5851            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5852        let locator = self.excerpt_locator_for_id(excerpt_id);
5853        if cursor.seek(&Some(locator), Bias::Left, &()) {
5854            let start = cursor.start().1.clone();
5855            let end = cursor.end(&()).1;
5856            let mut diff_transforms = self
5857                .diff_transforms
5858                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5859            diff_transforms.seek(&start, Bias::Left, &());
5860            let overshoot = start.0 - diff_transforms.start().0 .0;
5861            let start = diff_transforms.start().1 .0 + overshoot;
5862            diff_transforms.seek(&end, Bias::Right, &());
5863            let overshoot = end.0 - diff_transforms.start().0 .0;
5864            let end = diff_transforms.start().1 .0 + overshoot;
5865            Some(start..end)
5866        } else {
5867            None
5868        }
5869    }
5870
5871    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5872        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5873        let locator = self.excerpt_locator_for_id(excerpt_id);
5874        if cursor.seek(&Some(locator), Bias::Left, &()) {
5875            if let Some(excerpt) = cursor.item() {
5876                return Some(excerpt.range.context.clone());
5877            }
5878        }
5879        None
5880    }
5881
5882    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5883        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5884        let locator = self.excerpt_locator_for_id(excerpt_id);
5885        cursor.seek(&Some(locator), Bias::Left, &());
5886        if let Some(excerpt) = cursor.item() {
5887            if excerpt.id == excerpt_id {
5888                return Some(excerpt);
5889            }
5890        }
5891        None
5892    }
5893
5894    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5895    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5896        let range = range.start.to_offset(self)..range.end.to_offset(self);
5897        let mut cursor = self.cursor::<usize>();
5898        cursor.seek(&range.start);
5899
5900        let start_excerpt = cursor.excerpt()?;
5901        if range.end != range.start {
5902            cursor.seek_forward(&range.end);
5903            if cursor.excerpt()?.id != start_excerpt.id {
5904                return None;
5905            }
5906        }
5907
5908        cursor.seek_to_start_of_current_excerpt();
5909        let region = cursor.region()?;
5910        let offset = region.range.start;
5911        let buffer_offset = region.buffer_range.start;
5912        let excerpt_offset = cursor.excerpts.start().clone();
5913        Some(MultiBufferExcerpt {
5914            diff_transforms: cursor.diff_transforms,
5915            excerpt: start_excerpt,
5916            offset,
5917            buffer_offset,
5918            excerpt_offset,
5919        })
5920    }
5921
5922    pub fn selections_in_range<'a>(
5923        &'a self,
5924        range: &'a Range<Anchor>,
5925        include_local: bool,
5926    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5927        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5928        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5929        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5930        cursor.seek(start_locator, Bias::Left, &());
5931        cursor
5932            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5933            .flat_map(move |excerpt| {
5934                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5935                if excerpt.id == range.start.excerpt_id {
5936                    query_range.start = range.start.text_anchor;
5937                }
5938                if excerpt.id == range.end.excerpt_id {
5939                    query_range.end = range.end.text_anchor;
5940                }
5941
5942                excerpt
5943                    .buffer
5944                    .selections_in_range(query_range, include_local)
5945                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5946                        selections.map(move |selection| {
5947                            let mut start = Anchor {
5948                                buffer_id: Some(excerpt.buffer_id),
5949                                excerpt_id: excerpt.id,
5950                                text_anchor: selection.start,
5951                                diff_base_anchor: None,
5952                            };
5953                            let mut end = Anchor {
5954                                buffer_id: Some(excerpt.buffer_id),
5955                                excerpt_id: excerpt.id,
5956                                text_anchor: selection.end,
5957                                diff_base_anchor: None,
5958                            };
5959                            if range.start.cmp(&start, self).is_gt() {
5960                                start = range.start;
5961                            }
5962                            if range.end.cmp(&end, self).is_lt() {
5963                                end = range.end;
5964                            }
5965
5966                            (
5967                                replica_id,
5968                                line_mode,
5969                                cursor_shape,
5970                                Selection {
5971                                    id: selection.id,
5972                                    start,
5973                                    end,
5974                                    reversed: selection.reversed,
5975                                    goal: selection.goal,
5976                                },
5977                            )
5978                        })
5979                    })
5980            })
5981    }
5982
5983    pub fn show_headers(&self) -> bool {
5984        self.show_headers
5985    }
5986
5987    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5988        self.diffs.get(&buffer_id)
5989    }
5990}
5991
5992#[cfg(any(test, feature = "test-support"))]
5993impl MultiBufferSnapshot {
5994    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5995        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5996        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5997        start..end
5998    }
5999
6000    #[cfg(any(test, feature = "test-support"))]
6001    fn check_invariants(&self) {
6002        let excerpts = self.excerpts.items(&());
6003        let excerpt_ids = self.excerpt_ids.items(&());
6004
6005        for (ix, excerpt) in excerpts.iter().enumerate() {
6006            if ix == 0 {
6007                if excerpt.locator <= Locator::min() {
6008                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6009                }
6010            } else if excerpt.locator <= excerpts[ix - 1].locator {
6011                panic!("excerpts are out-of-order: {:?}", excerpts);
6012            }
6013        }
6014
6015        for (ix, entry) in excerpt_ids.iter().enumerate() {
6016            if ix == 0 {
6017                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6018                    panic!("invalid first excerpt id {:?}", entry.id);
6019                }
6020            } else if entry.id <= excerpt_ids[ix - 1].id {
6021                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6022            }
6023        }
6024
6025        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6026            panic!(
6027                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6028                self.excerpts.summary().text.len,
6029                self.diff_transforms.summary().input,
6030                self.diff_transforms.items(&()),
6031            );
6032        }
6033
6034        let mut prev_transform: Option<&DiffTransform> = None;
6035        for item in self.diff_transforms.iter() {
6036            if let DiffTransform::BufferContent {
6037                summary,
6038                inserted_hunk_info,
6039            } = item
6040            {
6041                if let Some(DiffTransform::BufferContent {
6042                    inserted_hunk_info: prev_inserted_hunk_info,
6043                    ..
6044                }) = prev_transform
6045                {
6046                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6047                        panic!(
6048                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6049                            self.diff_transforms.items(&()));
6050                    }
6051                }
6052                if summary.len == 0 && !self.is_empty() {
6053                    panic!("empty buffer content transform");
6054                }
6055            }
6056            prev_transform = Some(item);
6057        }
6058    }
6059}
6060
6061impl<'a, D> MultiBufferCursor<'a, D>
6062where
6063    D: TextDimension + Ord + Sub<D, Output = D>,
6064{
6065    fn seek(&mut self, position: &D) {
6066        self.cached_region.take();
6067        self.diff_transforms
6068            .seek(&OutputDimension(*position), Bias::Right, &());
6069        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6070            self.diff_transforms.prev(&());
6071        }
6072
6073        let mut excerpt_position = self.diff_transforms.start().1 .0;
6074        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6075            let overshoot = *position - self.diff_transforms.start().0 .0;
6076            excerpt_position.add_assign(&overshoot);
6077        }
6078
6079        self.excerpts
6080            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6081        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6082            self.excerpts.prev(&());
6083        }
6084    }
6085
6086    fn seek_forward(&mut self, position: &D) {
6087        self.cached_region.take();
6088        self.diff_transforms
6089            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6090        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6091            self.diff_transforms.prev(&());
6092        }
6093
6094        let overshoot = *position - self.diff_transforms.start().0 .0;
6095        let mut excerpt_position = self.diff_transforms.start().1 .0;
6096        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6097            excerpt_position.add_assign(&overshoot);
6098        }
6099
6100        self.excerpts
6101            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6102        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6103            self.excerpts.prev(&());
6104        }
6105    }
6106
6107    fn next_excerpt(&mut self) {
6108        self.excerpts.next(&());
6109        self.seek_to_start_of_current_excerpt();
6110    }
6111
6112    fn prev_excerpt(&mut self) {
6113        self.excerpts.prev(&());
6114        self.seek_to_start_of_current_excerpt();
6115    }
6116
6117    fn seek_to_start_of_current_excerpt(&mut self) {
6118        self.cached_region.take();
6119        self.diff_transforms
6120            .seek(self.excerpts.start(), Bias::Left, &());
6121        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6122            && self.diff_transforms.start().1 < *self.excerpts.start()
6123            && self.diff_transforms.next_item().is_some()
6124        {
6125            self.diff_transforms.next(&());
6126        }
6127    }
6128
6129    fn next(&mut self) {
6130        self.cached_region.take();
6131        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6132            cmp::Ordering::Less => self.diff_transforms.next(&()),
6133            cmp::Ordering::Greater => self.excerpts.next(&()),
6134            cmp::Ordering::Equal => {
6135                self.diff_transforms.next(&());
6136                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6137                    || self.diff_transforms.item().is_none()
6138                {
6139                    self.excerpts.next(&());
6140                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6141                    self.diff_transforms.item()
6142                {
6143                    if self
6144                        .excerpts
6145                        .item()
6146                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6147                    {
6148                        self.excerpts.next(&());
6149                    }
6150                }
6151            }
6152        }
6153    }
6154
6155    fn prev(&mut self) {
6156        self.cached_region.take();
6157        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6158            cmp::Ordering::Less => self.excerpts.prev(&()),
6159            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6160            cmp::Ordering::Equal => {
6161                self.diff_transforms.prev(&());
6162                if self.diff_transforms.start().1 < *self.excerpts.start()
6163                    || self.diff_transforms.item().is_none()
6164                {
6165                    self.excerpts.prev(&());
6166                }
6167            }
6168        }
6169    }
6170
6171    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6172        if self.cached_region.is_none() {
6173            self.cached_region = self.build_region();
6174        }
6175        self.cached_region.clone()
6176    }
6177
6178    fn is_at_end_of_excerpt(&mut self) -> bool {
6179        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6180            return false;
6181        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6182            || self.diff_transforms.item().is_none()
6183        {
6184            return true;
6185        }
6186
6187        let next_transform = self.diff_transforms.next_item();
6188        next_transform.map_or(true, |next_transform| match next_transform {
6189            DiffTransform::BufferContent { .. } => true,
6190            DiffTransform::DeletedHunk { hunk_info, .. } => self
6191                .excerpts
6192                .item()
6193                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6194        })
6195    }
6196
6197    fn main_buffer_position(&self) -> Option<D> {
6198        let excerpt = self.excerpts.item()?;
6199        let buffer = &excerpt.buffer;
6200        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6201        let mut buffer_start = buffer_context_start;
6202        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6203        buffer_start.add_assign(&overshoot);
6204        Some(buffer_start)
6205    }
6206
6207    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6208        let excerpt = self.excerpts.item()?;
6209        match self.diff_transforms.item()? {
6210            DiffTransform::DeletedHunk {
6211                buffer_id,
6212                base_text_byte_range,
6213                has_trailing_newline,
6214                hunk_info,
6215                ..
6216            } => {
6217                let diff = self.diffs.get(&buffer_id)?;
6218                let buffer = diff.base_text();
6219                let mut rope_cursor = buffer.as_rope().cursor(0);
6220                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6221                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6222                let mut buffer_end = buffer_start;
6223                buffer_end.add_assign(&buffer_range_len);
6224                let start = self.diff_transforms.start().0 .0;
6225                let end = self.diff_transforms.end(&()).0 .0;
6226                return Some(MultiBufferRegion {
6227                    buffer,
6228                    excerpt,
6229                    has_trailing_newline: *has_trailing_newline,
6230                    is_main_buffer: false,
6231                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6232                        hunk_info.hunk_secondary_status,
6233                    )),
6234                    buffer_range: buffer_start..buffer_end,
6235                    range: start..end,
6236                });
6237            }
6238            DiffTransform::BufferContent {
6239                inserted_hunk_info, ..
6240            } => {
6241                let buffer = &excerpt.buffer;
6242                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6243
6244                let mut start = self.diff_transforms.start().0 .0;
6245                let mut buffer_start = buffer_context_start;
6246                if self.diff_transforms.start().1 < *self.excerpts.start() {
6247                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6248                    start.add_assign(&overshoot);
6249                } else {
6250                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6251                    buffer_start.add_assign(&overshoot);
6252                }
6253
6254                let mut end;
6255                let mut buffer_end;
6256                let has_trailing_newline;
6257                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6258                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6259                    end = self.diff_transforms.end(&()).0 .0;
6260                    buffer_end = buffer_context_start;
6261                    buffer_end.add_assign(&overshoot);
6262                    has_trailing_newline = false;
6263                } else {
6264                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6265                    end = self.diff_transforms.start().0 .0;
6266                    end.add_assign(&overshoot);
6267                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6268                    has_trailing_newline = excerpt.has_trailing_newline;
6269                };
6270
6271                Some(MultiBufferRegion {
6272                    buffer,
6273                    excerpt,
6274                    has_trailing_newline,
6275                    is_main_buffer: true,
6276                    diff_hunk_status: inserted_hunk_info
6277                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6278                    buffer_range: buffer_start..buffer_end,
6279                    range: start..end,
6280                })
6281            }
6282        }
6283    }
6284
6285    fn excerpt(&self) -> Option<&'a Excerpt> {
6286        self.excerpts.item()
6287    }
6288}
6289
6290impl History {
6291    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6292        self.transaction_depth += 1;
6293        if self.transaction_depth == 1 {
6294            let id = self.next_transaction_id.tick();
6295            self.undo_stack.push(Transaction {
6296                id,
6297                buffer_transactions: Default::default(),
6298                first_edit_at: now,
6299                last_edit_at: now,
6300                suppress_grouping: false,
6301            });
6302            Some(id)
6303        } else {
6304            None
6305        }
6306    }
6307
6308    fn end_transaction(
6309        &mut self,
6310        now: Instant,
6311        buffer_transactions: HashMap<BufferId, TransactionId>,
6312    ) -> bool {
6313        assert_ne!(self.transaction_depth, 0);
6314        self.transaction_depth -= 1;
6315        if self.transaction_depth == 0 {
6316            if buffer_transactions.is_empty() {
6317                self.undo_stack.pop();
6318                false
6319            } else {
6320                self.redo_stack.clear();
6321                let transaction = self.undo_stack.last_mut().unwrap();
6322                transaction.last_edit_at = now;
6323                for (buffer_id, transaction_id) in buffer_transactions {
6324                    transaction
6325                        .buffer_transactions
6326                        .entry(buffer_id)
6327                        .or_insert(transaction_id);
6328                }
6329                true
6330            }
6331        } else {
6332            false
6333        }
6334    }
6335
6336    fn push_transaction<'a, T>(
6337        &mut self,
6338        buffer_transactions: T,
6339        now: Instant,
6340        cx: &Context<MultiBuffer>,
6341    ) where
6342        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6343    {
6344        assert_eq!(self.transaction_depth, 0);
6345        let transaction = Transaction {
6346            id: self.next_transaction_id.tick(),
6347            buffer_transactions: buffer_transactions
6348                .into_iter()
6349                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6350                .collect(),
6351            first_edit_at: now,
6352            last_edit_at: now,
6353            suppress_grouping: false,
6354        };
6355        if !transaction.buffer_transactions.is_empty() {
6356            self.undo_stack.push(transaction);
6357            self.redo_stack.clear();
6358        }
6359    }
6360
6361    fn finalize_last_transaction(&mut self) {
6362        if let Some(transaction) = self.undo_stack.last_mut() {
6363            transaction.suppress_grouping = true;
6364        }
6365    }
6366
6367    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6368        if let Some(ix) = self
6369            .undo_stack
6370            .iter()
6371            .rposition(|transaction| transaction.id == transaction_id)
6372        {
6373            Some(self.undo_stack.remove(ix))
6374        } else if let Some(ix) = self
6375            .redo_stack
6376            .iter()
6377            .rposition(|transaction| transaction.id == transaction_id)
6378        {
6379            Some(self.redo_stack.remove(ix))
6380        } else {
6381            None
6382        }
6383    }
6384
6385    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6386        self.undo_stack
6387            .iter()
6388            .find(|transaction| transaction.id == transaction_id)
6389            .or_else(|| {
6390                self.redo_stack
6391                    .iter()
6392                    .find(|transaction| transaction.id == transaction_id)
6393            })
6394    }
6395
6396    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6397        self.undo_stack
6398            .iter_mut()
6399            .find(|transaction| transaction.id == transaction_id)
6400            .or_else(|| {
6401                self.redo_stack
6402                    .iter_mut()
6403                    .find(|transaction| transaction.id == transaction_id)
6404            })
6405    }
6406
6407    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6408        assert_eq!(self.transaction_depth, 0);
6409        if let Some(transaction) = self.undo_stack.pop() {
6410            self.redo_stack.push(transaction);
6411            self.redo_stack.last_mut()
6412        } else {
6413            None
6414        }
6415    }
6416
6417    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6418        assert_eq!(self.transaction_depth, 0);
6419        if let Some(transaction) = self.redo_stack.pop() {
6420            self.undo_stack.push(transaction);
6421            self.undo_stack.last_mut()
6422        } else {
6423            None
6424        }
6425    }
6426
6427    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6428        let ix = self
6429            .undo_stack
6430            .iter()
6431            .rposition(|transaction| transaction.id == transaction_id)?;
6432        let transaction = self.undo_stack.remove(ix);
6433        self.redo_stack.push(transaction);
6434        self.redo_stack.last()
6435    }
6436
6437    fn group(&mut self) -> Option<TransactionId> {
6438        let mut count = 0;
6439        let mut transactions = self.undo_stack.iter();
6440        if let Some(mut transaction) = transactions.next_back() {
6441            while let Some(prev_transaction) = transactions.next_back() {
6442                if !prev_transaction.suppress_grouping
6443                    && transaction.first_edit_at - prev_transaction.last_edit_at
6444                        <= self.group_interval
6445                {
6446                    transaction = prev_transaction;
6447                    count += 1;
6448                } else {
6449                    break;
6450                }
6451            }
6452        }
6453        self.group_trailing(count)
6454    }
6455
6456    fn group_until(&mut self, transaction_id: TransactionId) {
6457        let mut count = 0;
6458        for transaction in self.undo_stack.iter().rev() {
6459            if transaction.id == transaction_id {
6460                self.group_trailing(count);
6461                break;
6462            } else if transaction.suppress_grouping {
6463                break;
6464            } else {
6465                count += 1;
6466            }
6467        }
6468    }
6469
6470    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6471        let new_len = self.undo_stack.len() - n;
6472        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6473        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6474            if let Some(transaction) = transactions_to_merge.last() {
6475                last_transaction.last_edit_at = transaction.last_edit_at;
6476            }
6477            for to_merge in transactions_to_merge {
6478                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6479                    last_transaction
6480                        .buffer_transactions
6481                        .entry(*buffer_id)
6482                        .or_insert(*transaction_id);
6483                }
6484            }
6485        }
6486
6487        self.undo_stack.truncate(new_len);
6488        self.undo_stack.last().map(|t| t.id)
6489    }
6490}
6491
6492impl Excerpt {
6493    fn new(
6494        id: ExcerptId,
6495        locator: Locator,
6496        buffer_id: BufferId,
6497        buffer: BufferSnapshot,
6498        range: ExcerptRange<text::Anchor>,
6499        has_trailing_newline: bool,
6500    ) -> Self {
6501        Excerpt {
6502            id,
6503            locator,
6504            max_buffer_row: range.context.end.to_point(&buffer).row,
6505            text_summary: buffer
6506                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6507            buffer_id,
6508            buffer,
6509            range,
6510            has_trailing_newline,
6511        }
6512    }
6513
6514    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6515        let content_start = self.range.context.start.to_offset(&self.buffer);
6516        let chunks_start = content_start + range.start;
6517        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6518
6519        let footer_height = if self.has_trailing_newline
6520            && range.start <= self.text_summary.len
6521            && range.end > self.text_summary.len
6522        {
6523            1
6524        } else {
6525            0
6526        };
6527
6528        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6529
6530        ExcerptChunks {
6531            excerpt_id: self.id,
6532            content_chunks,
6533            footer_height,
6534        }
6535    }
6536
6537    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6538        let content_start = self.range.context.start.to_offset(&self.buffer);
6539        let chunks_start = content_start + range.start;
6540        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6541        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6542        excerpt_chunks.footer_height = if self.has_trailing_newline
6543            && range.start <= self.text_summary.len
6544            && range.end > self.text_summary.len
6545        {
6546            1
6547        } else {
6548            0
6549        };
6550    }
6551
6552    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6553        if text_anchor
6554            .cmp(&self.range.context.start, &self.buffer)
6555            .is_lt()
6556        {
6557            self.range.context.start
6558        } else if text_anchor
6559            .cmp(&self.range.context.end, &self.buffer)
6560            .is_gt()
6561        {
6562            self.range.context.end
6563        } else {
6564            text_anchor
6565        }
6566    }
6567
6568    fn contains(&self, anchor: &Anchor) -> bool {
6569        Some(self.buffer_id) == anchor.buffer_id
6570            && self
6571                .range
6572                .context
6573                .start
6574                .cmp(&anchor.text_anchor, &self.buffer)
6575                .is_le()
6576            && self
6577                .range
6578                .context
6579                .end
6580                .cmp(&anchor.text_anchor, &self.buffer)
6581                .is_ge()
6582    }
6583
6584    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6585    fn buffer_start_offset(&self) -> usize {
6586        self.range.context.start.to_offset(&self.buffer)
6587    }
6588
6589    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6590    fn buffer_end_offset(&self) -> usize {
6591        self.buffer_start_offset() + self.text_summary.len
6592    }
6593}
6594
6595impl<'a> MultiBufferExcerpt<'a> {
6596    pub fn id(&self) -> ExcerptId {
6597        self.excerpt.id
6598    }
6599
6600    pub fn buffer_id(&self) -> BufferId {
6601        self.excerpt.buffer_id
6602    }
6603
6604    pub fn start_anchor(&self) -> Anchor {
6605        Anchor {
6606            buffer_id: Some(self.excerpt.buffer_id),
6607            excerpt_id: self.excerpt.id,
6608            text_anchor: self.excerpt.range.context.start,
6609            diff_base_anchor: None,
6610        }
6611    }
6612
6613    pub fn end_anchor(&self) -> Anchor {
6614        Anchor {
6615            buffer_id: Some(self.excerpt.buffer_id),
6616            excerpt_id: self.excerpt.id,
6617            text_anchor: self.excerpt.range.context.end,
6618            diff_base_anchor: None,
6619        }
6620    }
6621
6622    pub fn buffer(&self) -> &'a BufferSnapshot {
6623        &self.excerpt.buffer
6624    }
6625
6626    pub fn buffer_range(&self) -> Range<usize> {
6627        self.buffer_offset
6628            ..self
6629                .excerpt
6630                .range
6631                .context
6632                .end
6633                .to_offset(&self.excerpt.buffer.text)
6634    }
6635
6636    pub fn start_offset(&self) -> usize {
6637        self.offset
6638    }
6639
6640    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6641    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6642        self.map_range_to_buffer(offset..offset).start
6643    }
6644
6645    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6646    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6647        self.diff_transforms
6648            .seek(&OutputDimension(range.start), Bias::Right, &());
6649        let start = self.map_offset_to_buffer_internal(range.start);
6650        let end = if range.end > range.start {
6651            self.diff_transforms
6652                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6653            self.map_offset_to_buffer_internal(range.end)
6654        } else {
6655            start
6656        };
6657        start..end
6658    }
6659
6660    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6661        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6662        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6663            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6664        };
6665        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6666        self.buffer_offset + offset_in_excerpt
6667    }
6668
6669    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6670    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6671        self.map_range_from_buffer(buffer_offset..buffer_offset)
6672            .start
6673    }
6674
6675    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6676    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6677        if buffer_range.start < self.buffer_offset {
6678            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6679            return buffer_range;
6680        }
6681        let overshoot = buffer_range.start - self.buffer_offset;
6682        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6683        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6684        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6685            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6686            return buffer_range;
6687        }
6688        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6689        let start = self.diff_transforms.start().0 .0 + overshoot;
6690
6691        let end = if buffer_range.end > buffer_range.start {
6692            let overshoot = buffer_range.end - self.buffer_offset;
6693            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6694            self.diff_transforms
6695                .seek_forward(&excerpt_offset, Bias::Right, &());
6696            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6697            self.diff_transforms.start().0 .0 + overshoot
6698        } else {
6699            start
6700        };
6701
6702        start..end
6703    }
6704
6705    /// Returns true if the entirety of the given range is in the buffer's excerpt
6706    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6707        range.start >= self.excerpt.buffer_start_offset()
6708            && range.end <= self.excerpt.buffer_end_offset()
6709    }
6710
6711    pub fn max_buffer_row(&self) -> u32 {
6712        self.excerpt.max_buffer_row
6713    }
6714}
6715
6716impl ExcerptId {
6717    pub fn min() -> Self {
6718        Self(0)
6719    }
6720
6721    pub fn max() -> Self {
6722        Self(usize::MAX)
6723    }
6724
6725    pub fn to_proto(&self) -> u64 {
6726        self.0 as _
6727    }
6728
6729    pub fn from_proto(proto: u64) -> Self {
6730        Self(proto as _)
6731    }
6732
6733    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6734        let a = snapshot.excerpt_locator_for_id(*self);
6735        let b = snapshot.excerpt_locator_for_id(*other);
6736        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6737    }
6738}
6739
6740impl From<ExcerptId> for usize {
6741    fn from(val: ExcerptId) -> Self {
6742        val.0
6743    }
6744}
6745
6746impl fmt::Debug for Excerpt {
6747    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6748        f.debug_struct("Excerpt")
6749            .field("id", &self.id)
6750            .field("locator", &self.locator)
6751            .field("buffer_id", &self.buffer_id)
6752            .field("range", &self.range)
6753            .field("text_summary", &self.text_summary)
6754            .field("has_trailing_newline", &self.has_trailing_newline)
6755            .finish()
6756    }
6757}
6758
6759impl sum_tree::Item for Excerpt {
6760    type Summary = ExcerptSummary;
6761
6762    fn summary(&self, _cx: &()) -> Self::Summary {
6763        let mut text = self.text_summary;
6764        if self.has_trailing_newline {
6765            text += TextSummary::from("\n");
6766        }
6767        ExcerptSummary {
6768            excerpt_id: self.id,
6769            excerpt_locator: self.locator.clone(),
6770            widest_line_number: self.max_buffer_row,
6771            text,
6772        }
6773    }
6774}
6775
6776impl sum_tree::Item for ExcerptIdMapping {
6777    type Summary = ExcerptId;
6778
6779    fn summary(&self, _cx: &()) -> Self::Summary {
6780        self.id
6781    }
6782}
6783
6784impl sum_tree::KeyedItem for ExcerptIdMapping {
6785    type Key = ExcerptId;
6786
6787    fn key(&self) -> Self::Key {
6788        self.id
6789    }
6790}
6791
6792impl DiffTransform {
6793    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6794        match self {
6795            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6796            DiffTransform::BufferContent {
6797                inserted_hunk_info, ..
6798            } => *inserted_hunk_info,
6799        }
6800    }
6801}
6802
6803impl sum_tree::Item for DiffTransform {
6804    type Summary = DiffTransformSummary;
6805
6806    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6807        match self {
6808            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6809                input: *summary,
6810                output: *summary,
6811            },
6812            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6813                input: TextSummary::default(),
6814                output: *summary,
6815            },
6816        }
6817    }
6818}
6819
6820impl DiffTransformSummary {
6821    fn excerpt_len(&self) -> ExcerptOffset {
6822        ExcerptOffset::new(self.input.len)
6823    }
6824}
6825
6826impl sum_tree::Summary for DiffTransformSummary {
6827    type Context = ();
6828
6829    fn zero(_: &Self::Context) -> Self {
6830        DiffTransformSummary {
6831            input: TextSummary::default(),
6832            output: TextSummary::default(),
6833        }
6834    }
6835
6836    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6837        self.input += &summary.input;
6838        self.output += &summary.output;
6839    }
6840}
6841
6842impl sum_tree::Summary for ExcerptId {
6843    type Context = ();
6844
6845    fn zero(_cx: &()) -> Self {
6846        Default::default()
6847    }
6848
6849    fn add_summary(&mut self, other: &Self, _: &()) {
6850        *self = *other;
6851    }
6852}
6853
6854impl sum_tree::Summary for ExcerptSummary {
6855    type Context = ();
6856
6857    fn zero(_cx: &()) -> Self {
6858        Default::default()
6859    }
6860
6861    fn add_summary(&mut self, summary: &Self, _: &()) {
6862        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6863        self.excerpt_locator = summary.excerpt_locator.clone();
6864        self.text.add_summary(&summary.text, &());
6865        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6866    }
6867}
6868
6869impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6870    fn zero(_cx: &()) -> Self {
6871        Default::default()
6872    }
6873
6874    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6875        self.value += summary.text.len;
6876    }
6877}
6878
6879impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6880    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6881        Ord::cmp(&self.value, &cursor_location.text.len)
6882    }
6883}
6884
6885impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6886    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6887        Ord::cmp(&Some(self), cursor_location)
6888    }
6889}
6890
6891impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6892    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6893        Ord::cmp(self, &cursor_location.excerpt_locator)
6894    }
6895}
6896
6897impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6898    fn zero(_cx: &()) -> Self {
6899        Default::default()
6900    }
6901
6902    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6903        self.value += summary.text.lines;
6904    }
6905}
6906
6907impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6908    for ExcerptDimension<D>
6909{
6910    fn zero(_: &()) -> Self {
6911        ExcerptDimension(D::default())
6912    }
6913
6914    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6915        self.0.add_assign(&D::from_text_summary(&summary.text))
6916    }
6917}
6918
6919impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6920    fn zero(_cx: &()) -> Self {
6921        Default::default()
6922    }
6923
6924    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6925        *self = Some(&summary.excerpt_locator);
6926    }
6927}
6928
6929impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6930    fn zero(_cx: &()) -> Self {
6931        Default::default()
6932    }
6933
6934    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6935        *self = Some(summary.excerpt_id);
6936    }
6937}
6938
6939#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6940struct ExcerptDimension<T>(T);
6941
6942#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6943struct OutputDimension<T>(T);
6944
6945impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6946    fn zero(_: &()) -> Self {
6947        ExcerptOffset::new(0)
6948    }
6949
6950    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6951        self.value += summary.input.len;
6952    }
6953}
6954
6955impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6956    fn zero(_: &()) -> Self {
6957        ExcerptPoint::new(0, 0)
6958    }
6959
6960    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6961        self.value += summary.input.lines;
6962    }
6963}
6964
6965impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6966    for ExcerptDimension<D>
6967{
6968    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6969        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6970    }
6971}
6972
6973impl<D: TextDimension + Ord>
6974    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6975    for ExcerptDimension<D>
6976{
6977    fn cmp(
6978        &self,
6979        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6980        _: &(),
6981    ) -> cmp::Ordering {
6982        Ord::cmp(&self.0, &cursor_location.1 .0)
6983    }
6984}
6985
6986impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6987    fn zero(_: &()) -> Self {
6988        ExcerptDimension(D::default())
6989    }
6990
6991    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6992        self.0.add_assign(&D::from_text_summary(&summary.input))
6993    }
6994}
6995
6996impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6997    fn zero(_: &()) -> Self {
6998        OutputDimension(D::default())
6999    }
7000
7001    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7002        self.0.add_assign(&D::from_text_summary(&summary.output))
7003    }
7004}
7005
7006impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7007    fn zero(_: &()) -> Self {
7008        TextSummary::default()
7009    }
7010
7011    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7012        *self += summary.output
7013    }
7014}
7015
7016impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7017    fn zero(_: &()) -> Self {
7018        0
7019    }
7020
7021    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7022        *self += summary.output.len
7023    }
7024}
7025
7026impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7027    fn zero(_: &()) -> Self {
7028        Point::new(0, 0)
7029    }
7030
7031    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7032        *self += summary.output.lines
7033    }
7034}
7035
7036impl MultiBufferRows<'_> {
7037    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7038        self.point = Point::new(row, 0);
7039        self.cursor.seek(&self.point);
7040    }
7041}
7042
7043impl Iterator for MultiBufferRows<'_> {
7044    type Item = RowInfo;
7045
7046    fn next(&mut self) -> Option<Self::Item> {
7047        if self.is_empty && self.point.row == 0 {
7048            self.point += Point::new(1, 0);
7049            return Some(RowInfo {
7050                buffer_id: None,
7051                buffer_row: Some(0),
7052                multibuffer_row: Some(MultiBufferRow(0)),
7053                diff_status: None,
7054            });
7055        }
7056
7057        let mut region = self.cursor.region()?;
7058        while self.point >= region.range.end {
7059            self.cursor.next();
7060            if let Some(next_region) = self.cursor.region() {
7061                region = next_region;
7062            } else {
7063                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7064                    let multibuffer_row = MultiBufferRow(self.point.row);
7065                    self.point += Point::new(1, 0);
7066                    let last_excerpt = self
7067                        .cursor
7068                        .excerpts
7069                        .item()
7070                        .or(self.cursor.excerpts.prev_item())?;
7071                    let last_row = last_excerpt
7072                        .range
7073                        .context
7074                        .end
7075                        .to_point(&last_excerpt.buffer)
7076                        .row;
7077                    return Some(RowInfo {
7078                        buffer_id: Some(last_excerpt.buffer_id),
7079                        buffer_row: Some(last_row),
7080                        multibuffer_row: Some(multibuffer_row),
7081                        diff_status: None,
7082                    });
7083                } else {
7084                    return None;
7085                }
7086            };
7087        }
7088
7089        let overshoot = self.point - region.range.start;
7090        let buffer_point = region.buffer_range.start + overshoot;
7091        let result = Some(RowInfo {
7092            buffer_id: Some(region.buffer.remote_id()),
7093            buffer_row: Some(buffer_point.row),
7094            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7095            diff_status: region
7096                .diff_hunk_status
7097                .filter(|_| self.point < region.range.end),
7098        });
7099        self.point += Point::new(1, 0);
7100        result
7101    }
7102}
7103
7104impl<'a> MultiBufferChunks<'a> {
7105    pub fn offset(&self) -> usize {
7106        self.range.start
7107    }
7108
7109    pub fn seek(&mut self, range: Range<usize>) {
7110        self.diff_transforms.seek(&range.end, Bias::Right, &());
7111        let mut excerpt_end = self.diff_transforms.start().1;
7112        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7113            let overshoot = range.end - self.diff_transforms.start().0;
7114            excerpt_end.value += overshoot;
7115        }
7116
7117        self.diff_transforms.seek(&range.start, Bias::Right, &());
7118        let mut excerpt_start = self.diff_transforms.start().1;
7119        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7120            let overshoot = range.start - self.diff_transforms.start().0;
7121            excerpt_start.value += overshoot;
7122        }
7123
7124        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7125        self.buffer_chunk.take();
7126        self.range = range;
7127    }
7128
7129    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7130        self.excerpt_offset_range = new_range.clone();
7131        self.excerpts.seek(&new_range.start, Bias::Right, &());
7132        if let Some(excerpt) = self.excerpts.item() {
7133            let excerpt_start = *self.excerpts.start();
7134            if let Some(excerpt_chunks) = self
7135                .excerpt_chunks
7136                .as_mut()
7137                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7138            {
7139                excerpt.seek_chunks(
7140                    excerpt_chunks,
7141                    (self.excerpt_offset_range.start - excerpt_start).value
7142                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7143                );
7144            } else {
7145                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7146                    (self.excerpt_offset_range.start - excerpt_start).value
7147                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7148                    self.language_aware,
7149                ));
7150            }
7151        } else {
7152            self.excerpt_chunks = None;
7153        }
7154    }
7155
7156    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7157        loop {
7158            if self.excerpt_offset_range.is_empty() {
7159                return None;
7160            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7161                self.excerpt_offset_range.start.value += chunk.text.len();
7162                return Some(chunk);
7163            } else {
7164                self.excerpts.next(&());
7165                let excerpt = self.excerpts.item()?;
7166                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7167                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7168                    self.language_aware,
7169                ));
7170            }
7171        }
7172    }
7173}
7174
7175impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7176    type Item = &'a str;
7177
7178    fn next(&mut self) -> Option<Self::Item> {
7179        let mut region = self.cursor.region()?;
7180        if self.offset == region.range.start {
7181            self.cursor.prev();
7182            region = self.cursor.region()?;
7183            let start_overshoot = self.start.saturating_sub(region.range.start);
7184            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7185                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7186            ));
7187        }
7188
7189        if self.offset == region.range.end && region.has_trailing_newline {
7190            self.offset -= 1;
7191            Some("\n")
7192        } else {
7193            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7194            self.offset -= chunk.len();
7195            Some(chunk)
7196        }
7197    }
7198}
7199
7200impl<'a> Iterator for MultiBufferChunks<'a> {
7201    type Item = Chunk<'a>;
7202
7203    fn next(&mut self) -> Option<Chunk<'a>> {
7204        if self.range.start >= self.range.end {
7205            return None;
7206        }
7207        if self.range.start == self.diff_transforms.end(&()).0 {
7208            self.diff_transforms.next(&());
7209        }
7210
7211        let diff_transform_start = self.diff_transforms.start().0;
7212        let diff_transform_end = self.diff_transforms.end(&()).0;
7213        debug_assert!(self.range.start < diff_transform_end);
7214
7215        let diff_transform = self.diff_transforms.item()?;
7216        match diff_transform {
7217            DiffTransform::BufferContent { .. } => {
7218                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7219                    chunk
7220                } else {
7221                    let chunk = self.next_excerpt_chunk().unwrap();
7222                    self.buffer_chunk.insert(chunk)
7223                };
7224
7225                let chunk_end = self.range.start + chunk.text.len();
7226                let diff_transform_end = diff_transform_end.min(self.range.end);
7227
7228                if diff_transform_end < chunk_end {
7229                    let (before, after) =
7230                        chunk.text.split_at(diff_transform_end - self.range.start);
7231                    self.range.start = diff_transform_end;
7232                    chunk.text = after;
7233                    Some(Chunk {
7234                        text: before,
7235                        ..chunk.clone()
7236                    })
7237                } else {
7238                    self.range.start = chunk_end;
7239                    self.buffer_chunk.take()
7240                }
7241            }
7242            DiffTransform::DeletedHunk {
7243                buffer_id,
7244                base_text_byte_range,
7245                has_trailing_newline,
7246                ..
7247            } => {
7248                let base_text_start =
7249                    base_text_byte_range.start + self.range.start - diff_transform_start;
7250                let base_text_end =
7251                    base_text_byte_range.start + self.range.end - diff_transform_start;
7252                let base_text_end = base_text_end.min(base_text_byte_range.end);
7253
7254                let mut chunks = if let Some((_, mut chunks)) = self
7255                    .diff_base_chunks
7256                    .take()
7257                    .filter(|(id, _)| id == buffer_id)
7258                {
7259                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7260                    {
7261                        chunks.seek(base_text_start..base_text_end);
7262                    }
7263                    chunks
7264                } else {
7265                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7266                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7267                };
7268
7269                let chunk = if let Some(chunk) = chunks.next() {
7270                    self.range.start += chunk.text.len();
7271                    self.diff_base_chunks = Some((*buffer_id, chunks));
7272                    chunk
7273                } else {
7274                    debug_assert!(has_trailing_newline);
7275                    self.range.start += "\n".len();
7276                    Chunk {
7277                        text: "\n",
7278                        ..Default::default()
7279                    }
7280                };
7281                Some(chunk)
7282            }
7283        }
7284    }
7285}
7286
7287impl MultiBufferBytes<'_> {
7288    fn consume(&mut self, len: usize) {
7289        self.range.start += len;
7290        self.chunk = &self.chunk[len..];
7291
7292        if !self.range.is_empty() && self.chunk.is_empty() {
7293            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7294                self.chunk = chunk;
7295            } else if self.has_trailing_newline {
7296                self.has_trailing_newline = false;
7297                self.chunk = b"\n";
7298            } else {
7299                self.cursor.next();
7300                if let Some(region) = self.cursor.region() {
7301                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7302                        region.buffer_range.start
7303                            ..(region.buffer_range.start + self.range.end - region.range.start)
7304                                .min(region.buffer_range.end),
7305                    );
7306                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7307                    self.excerpt_bytes = Some(excerpt_bytes);
7308                    self.has_trailing_newline =
7309                        region.has_trailing_newline && self.range.end >= region.range.end;
7310                    if self.chunk.is_empty() && self.has_trailing_newline {
7311                        self.has_trailing_newline = false;
7312                        self.chunk = b"\n";
7313                    }
7314                }
7315            }
7316        }
7317    }
7318}
7319
7320impl<'a> Iterator for MultiBufferBytes<'a> {
7321    type Item = &'a [u8];
7322
7323    fn next(&mut self) -> Option<Self::Item> {
7324        let chunk = self.chunk;
7325        if chunk.is_empty() {
7326            None
7327        } else {
7328            self.consume(chunk.len());
7329            Some(chunk)
7330        }
7331    }
7332}
7333
7334impl io::Read for MultiBufferBytes<'_> {
7335    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7336        let len = cmp::min(buf.len(), self.chunk.len());
7337        buf[..len].copy_from_slice(&self.chunk[..len]);
7338        if len > 0 {
7339            self.consume(len);
7340        }
7341        Ok(len)
7342    }
7343}
7344
7345impl io::Read for ReversedMultiBufferBytes<'_> {
7346    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7347        let len = cmp::min(buf.len(), self.chunk.len());
7348        buf[..len].copy_from_slice(&self.chunk[..len]);
7349        buf[..len].reverse();
7350        if len > 0 {
7351            self.range.end -= len;
7352            self.chunk = &self.chunk[..self.chunk.len() - len];
7353            if !self.range.is_empty() && self.chunk.is_empty() {
7354                if let Some(chunk) = self.chunks.next() {
7355                    self.chunk = chunk.as_bytes();
7356                }
7357            }
7358        }
7359        Ok(len)
7360    }
7361}
7362
7363impl<'a> Iterator for ExcerptChunks<'a> {
7364    type Item = Chunk<'a>;
7365
7366    fn next(&mut self) -> Option<Self::Item> {
7367        if let Some(chunk) = self.content_chunks.next() {
7368            return Some(chunk);
7369        }
7370
7371        if self.footer_height > 0 {
7372            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7373            self.footer_height = 0;
7374            return Some(Chunk {
7375                text,
7376                ..Default::default()
7377            });
7378        }
7379
7380        None
7381    }
7382}
7383
7384impl ToOffset for Point {
7385    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7386        snapshot.point_to_offset(*self)
7387    }
7388}
7389
7390impl ToOffset for usize {
7391    #[track_caller]
7392    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7393        assert!(*self <= snapshot.len(), "offset is out of range");
7394        *self
7395    }
7396}
7397
7398impl ToOffset for OffsetUtf16 {
7399    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7400        snapshot.offset_utf16_to_offset(*self)
7401    }
7402}
7403
7404impl ToOffset for PointUtf16 {
7405    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7406        snapshot.point_utf16_to_offset(*self)
7407    }
7408}
7409
7410impl ToOffsetUtf16 for OffsetUtf16 {
7411    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7412        *self
7413    }
7414}
7415
7416impl ToOffsetUtf16 for usize {
7417    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7418        snapshot.offset_to_offset_utf16(*self)
7419    }
7420}
7421
7422impl ToPoint for usize {
7423    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7424        snapshot.offset_to_point(*self)
7425    }
7426}
7427
7428impl ToPoint for Point {
7429    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7430        *self
7431    }
7432}
7433
7434impl ToPointUtf16 for usize {
7435    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7436        snapshot.offset_to_point_utf16(*self)
7437    }
7438}
7439
7440impl ToPointUtf16 for Point {
7441    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7442        snapshot.point_to_point_utf16(*self)
7443    }
7444}
7445
7446impl ToPointUtf16 for PointUtf16 {
7447    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7448        *self
7449    }
7450}
7451
7452impl From<ExcerptId> for EntityId {
7453    fn from(id: ExcerptId) -> Self {
7454        EntityId::from(id.0 as u64)
7455    }
7456}
7457
7458pub fn build_excerpt_ranges<T>(
7459    buffer: &BufferSnapshot,
7460    ranges: &[Range<T>],
7461    context_line_count: u32,
7462) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7463where
7464    T: text::ToPoint,
7465{
7466    let max_point = buffer.max_point();
7467    let mut range_counts = Vec::new();
7468    let mut excerpt_ranges = Vec::new();
7469    let mut range_iter = ranges
7470        .iter()
7471        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7472        .peekable();
7473    while let Some(range) = range_iter.next() {
7474        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7475        let row = (range.end.row + context_line_count).min(max_point.row);
7476        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7477
7478        let mut ranges_in_excerpt = 1;
7479
7480        while let Some(next_range) = range_iter.peek() {
7481            if next_range.start.row <= excerpt_end.row + context_line_count {
7482                let row = (next_range.end.row + context_line_count).min(max_point.row);
7483                excerpt_end = Point::new(row, buffer.line_len(row));
7484
7485                ranges_in_excerpt += 1;
7486                range_iter.next();
7487            } else {
7488                break;
7489            }
7490        }
7491
7492        excerpt_ranges.push(ExcerptRange {
7493            context: excerpt_start..excerpt_end,
7494            primary: Some(range),
7495        });
7496        range_counts.push(ranges_in_excerpt);
7497    }
7498
7499    (excerpt_ranges, range_counts)
7500}