multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  47use text::{
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50    BufferId, Edit, LineIndent, TextSummary,
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    diffs: HashMap<BufferId, DiffState>,
  72    all_diff_hunks_expanded: bool,
  73    subscriptions: Topic,
  74    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  75    singleton: bool,
  76    history: History,
  77    title: Option<String>,
  78    capability: Capability,
  79}
  80
  81#[derive(Clone, Debug, PartialEq, Eq)]
  82pub enum MultiOrSingleBufferOffsetRange {
  83    Single(Range<usize>),
  84    Multi(Range<usize>),
  85}
  86
  87#[derive(Clone, Debug, PartialEq, Eq)]
  88pub enum Event {
  89    ExcerptsAdded {
  90        buffer: Entity<Buffer>,
  91        predecessor: ExcerptId,
  92        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  93    },
  94    ExcerptsRemoved {
  95        ids: Vec<ExcerptId>,
  96    },
  97    ExcerptsExpanded {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsEdited {
 101        excerpt_ids: Vec<ExcerptId>,
 102        buffer_ids: Vec<BufferId>,
 103    },
 104    DiffHunksToggled,
 105    Edited {
 106        singleton_buffer_edited: bool,
 107        edited_buffer: Option<Entity<Buffer>>,
 108    },
 109    TransactionUndone {
 110        transaction_id: TransactionId,
 111    },
 112    Reloaded,
 113    ReloadNeeded,
 114
 115    LanguageChanged(BufferId),
 116    CapabilityChanged,
 117    Reparsed(BufferId),
 118    Saved,
 119    FileHandleChanged,
 120    Closed,
 121    Discarded,
 122    DirtyChanged,
 123    DiagnosticsUpdated,
 124}
 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
 159#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 160pub struct PathKey {
 161    namespace: &'static str,
 162    path: Arc<Path>,
 163}
 164
 165impl PathKey {
 166    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 167        Self { namespace, path }
 168    }
 169
 170    pub fn path(&self) -> &Arc<Path> {
 171        &self.path
 172    }
 173}
 174
 175pub type MultiBufferPoint = Point;
 176type ExcerptOffset = TypedOffset<Excerpt>;
 177type ExcerptPoint = TypedPoint<Excerpt>;
 178
 179#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 180#[serde(transparent)]
 181pub struct MultiBufferRow(pub u32);
 182
 183impl MultiBufferRow {
 184    pub const MIN: Self = Self(0);
 185    pub const MAX: Self = Self(u32::MAX);
 186}
 187
 188impl std::ops::Add<usize> for MultiBufferRow {
 189    type Output = Self;
 190
 191    fn add(self, rhs: usize) -> Self::Output {
 192        MultiBufferRow(self.0 + rhs as u32)
 193    }
 194}
 195
 196#[derive(Clone)]
 197struct History {
 198    next_transaction_id: TransactionId,
 199    undo_stack: Vec<Transaction>,
 200    redo_stack: Vec<Transaction>,
 201    transaction_depth: usize,
 202    group_interval: Duration,
 203}
 204
 205#[derive(Clone)]
 206struct Transaction {
 207    id: TransactionId,
 208    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 209    first_edit_at: Instant,
 210    last_edit_at: Instant,
 211    suppress_grouping: bool,
 212}
 213
 214pub trait ToOffset: 'static + fmt::Debug {
 215    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 216}
 217
 218pub trait ToOffsetUtf16: 'static + fmt::Debug {
 219    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 220}
 221
 222pub trait ToPoint: 'static + fmt::Debug {
 223    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 224}
 225
 226pub trait ToPointUtf16: 'static + fmt::Debug {
 227    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 228}
 229
 230struct BufferState {
 231    buffer: Entity<Buffer>,
 232    last_version: clock::Global,
 233    last_non_text_state_update_count: usize,
 234    excerpts: Vec<Locator>,
 235    _subscriptions: [gpui::Subscription; 2],
 236}
 237
 238struct DiffState {
 239    diff: Entity<BufferDiff>,
 240    _subscription: gpui::Subscription,
 241}
 242
 243impl DiffState {
 244    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 245        DiffState {
 246            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 247                BufferDiffEvent::DiffChanged { changed_range } => {
 248                    let changed_range = if let Some(changed_range) = changed_range {
 249                        changed_range.clone()
 250                    } else if diff.read(cx).base_text().is_none() && this.all_diff_hunks_expanded {
 251                        text::Anchor::MIN..text::Anchor::MAX
 252                    } else {
 253                        return;
 254                    };
 255                    this.buffer_diff_changed(diff, changed_range, cx)
 256                }
 257                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 258            }),
 259            diff,
 260        }
 261    }
 262}
 263
 264/// The contents of a [`MultiBuffer`] at a single point in time.
 265#[derive(Clone, Default)]
 266pub struct MultiBufferSnapshot {
 267    singleton: bool,
 268    excerpts: SumTree<Excerpt>,
 269    excerpt_ids: SumTree<ExcerptIdMapping>,
 270    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 271    diff_transforms: SumTree<DiffTransform>,
 272    trailing_excerpt_update_count: usize,
 273    non_text_state_update_count: usize,
 274    edit_count: usize,
 275    is_dirty: bool,
 276    has_deleted_file: bool,
 277    has_conflict: bool,
 278    show_headers: bool,
 279}
 280
 281#[derive(Debug, Clone)]
 282enum DiffTransform {
 283    BufferContent {
 284        summary: TextSummary,
 285        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 286    },
 287    DeletedHunk {
 288        summary: TextSummary,
 289        buffer_id: BufferId,
 290        hunk_info: DiffTransformHunkInfo,
 291        base_text_byte_range: Range<usize>,
 292        has_trailing_newline: bool,
 293    },
 294}
 295
 296#[derive(Clone, Copy, Debug)]
 297struct DiffTransformHunkInfo {
 298    excerpt_id: ExcerptId,
 299    hunk_start_anchor: text::Anchor,
 300    hunk_secondary_status: DiffHunkSecondaryStatus,
 301}
 302
 303impl Eq for DiffTransformHunkInfo {}
 304
 305impl PartialEq for DiffTransformHunkInfo {
 306    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 307        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 308    }
 309}
 310
 311impl std::hash::Hash for DiffTransformHunkInfo {
 312    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 313        self.excerpt_id.hash(state);
 314        self.hunk_start_anchor.hash(state);
 315    }
 316}
 317
 318#[derive(Clone)]
 319pub struct ExcerptInfo {
 320    pub id: ExcerptId,
 321    pub buffer: BufferSnapshot,
 322    pub buffer_id: BufferId,
 323    pub range: ExcerptRange<text::Anchor>,
 324    pub end_row: MultiBufferRow,
 325}
 326
 327impl std::fmt::Debug for ExcerptInfo {
 328    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 329        f.debug_struct(type_name::<Self>())
 330            .field("id", &self.id)
 331            .field("buffer_id", &self.buffer_id)
 332            .field("path", &self.buffer.file().map(|f| f.path()))
 333            .field("range", &self.range)
 334            .finish()
 335    }
 336}
 337
 338/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 339#[derive(Debug)]
 340pub struct ExcerptBoundary {
 341    pub prev: Option<ExcerptInfo>,
 342    pub next: Option<ExcerptInfo>,
 343    /// The row in the `MultiBuffer` where the boundary is located
 344    pub row: MultiBufferRow,
 345}
 346
 347impl ExcerptBoundary {
 348    pub fn starts_new_buffer(&self) -> bool {
 349        match (self.prev.as_ref(), self.next.as_ref()) {
 350            (None, _) => true,
 351            (Some(_), None) => false,
 352            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 353        }
 354    }
 355}
 356
 357#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 358pub struct RowInfo {
 359    pub buffer_id: Option<BufferId>,
 360    pub buffer_row: Option<u32>,
 361    pub multibuffer_row: Option<MultiBufferRow>,
 362    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 363}
 364
 365/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 366#[derive(Clone)]
 367struct Excerpt {
 368    /// The unique identifier for this excerpt
 369    id: ExcerptId,
 370    /// The location of the excerpt in the [`MultiBuffer`]
 371    locator: Locator,
 372    /// The buffer being excerpted
 373    buffer_id: BufferId,
 374    /// A snapshot of the buffer being excerpted
 375    buffer: BufferSnapshot,
 376    /// The range of the buffer to be shown in the excerpt
 377    range: ExcerptRange<text::Anchor>,
 378    /// The last row in the excerpted slice of the buffer
 379    max_buffer_row: BufferRow,
 380    /// A summary of the text in the excerpt
 381    text_summary: TextSummary,
 382    has_trailing_newline: bool,
 383}
 384
 385/// A public view into an `Excerpt` in a [`MultiBuffer`].
 386///
 387/// Contains methods for getting the [`Buffer`] of the excerpt,
 388/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 389#[derive(Clone)]
 390pub struct MultiBufferExcerpt<'a> {
 391    excerpt: &'a Excerpt,
 392    diff_transforms:
 393        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 394    offset: usize,
 395    excerpt_offset: ExcerptDimension<usize>,
 396    buffer_offset: usize,
 397}
 398
 399#[derive(Clone, Debug)]
 400struct ExcerptIdMapping {
 401    id: ExcerptId,
 402    locator: Locator,
 403}
 404
 405/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 406/// These ranges are relative to the buffer itself
 407#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 408pub struct ExcerptRange<T> {
 409    /// The full range of text to be shown in the excerpt.
 410    pub context: Range<T>,
 411    /// The primary range of text to be highlighted in the excerpt.
 412    /// In a multi-buffer search, this would be the text that matched the search
 413    pub primary: Option<Range<T>>,
 414}
 415
 416#[derive(Clone, Debug, Default)]
 417pub struct ExcerptSummary {
 418    excerpt_id: ExcerptId,
 419    /// The location of the last [`Excerpt`] being summarized
 420    excerpt_locator: Locator,
 421    widest_line_number: u32,
 422    text: TextSummary,
 423}
 424
 425#[derive(Debug, Clone)]
 426pub struct DiffTransformSummary {
 427    input: TextSummary,
 428    output: TextSummary,
 429}
 430
 431#[derive(Clone)]
 432pub struct MultiBufferRows<'a> {
 433    point: Point,
 434    is_empty: bool,
 435    cursor: MultiBufferCursor<'a, Point>,
 436}
 437
 438pub struct MultiBufferChunks<'a> {
 439    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 440    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 441    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 442    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 443    buffer_chunk: Option<Chunk<'a>>,
 444    range: Range<usize>,
 445    excerpt_offset_range: Range<ExcerptOffset>,
 446    excerpt_chunks: Option<ExcerptChunks<'a>>,
 447    language_aware: bool,
 448}
 449
 450pub struct ReversedMultiBufferChunks<'a> {
 451    cursor: MultiBufferCursor<'a, usize>,
 452    current_chunks: Option<rope::Chunks<'a>>,
 453    start: usize,
 454    offset: usize,
 455}
 456
 457pub struct MultiBufferBytes<'a> {
 458    range: Range<usize>,
 459    cursor: MultiBufferCursor<'a, usize>,
 460    excerpt_bytes: Option<text::Bytes<'a>>,
 461    has_trailing_newline: bool,
 462    chunk: &'a [u8],
 463}
 464
 465pub struct ReversedMultiBufferBytes<'a> {
 466    range: Range<usize>,
 467    chunks: ReversedMultiBufferChunks<'a>,
 468    chunk: &'a [u8],
 469}
 470
 471#[derive(Clone)]
 472struct MultiBufferCursor<'a, D: TextDimension> {
 473    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 474    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 475    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 476    cached_region: Option<MultiBufferRegion<'a, D>>,
 477}
 478
 479#[derive(Clone)]
 480struct MultiBufferRegion<'a, D: TextDimension> {
 481    buffer: &'a BufferSnapshot,
 482    is_main_buffer: bool,
 483    diff_hunk_status: Option<DiffHunkStatus>,
 484    excerpt: &'a Excerpt,
 485    buffer_range: Range<D>,
 486    range: Range<D>,
 487    has_trailing_newline: bool,
 488}
 489
 490struct ExcerptChunks<'a> {
 491    excerpt_id: ExcerptId,
 492    content_chunks: BufferChunks<'a>,
 493    footer_height: usize,
 494}
 495
 496#[derive(Debug)]
 497struct BufferEdit {
 498    range: Range<usize>,
 499    new_text: Arc<str>,
 500    is_insertion: bool,
 501    original_start_column: u32,
 502    excerpt_id: ExcerptId,
 503}
 504
 505#[derive(Clone, Copy, Debug, PartialEq)]
 506enum DiffChangeKind {
 507    BufferEdited,
 508    DiffUpdated { base_changed: bool },
 509    ExpandOrCollapseHunks { expand: bool },
 510}
 511
 512#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 513pub enum ExpandExcerptDirection {
 514    Up,
 515    Down,
 516    UpAndDown,
 517}
 518
 519impl ExpandExcerptDirection {
 520    pub fn should_expand_up(&self) -> bool {
 521        match self {
 522            ExpandExcerptDirection::Up => true,
 523            ExpandExcerptDirection::Down => false,
 524            ExpandExcerptDirection::UpAndDown => true,
 525        }
 526    }
 527
 528    pub fn should_expand_down(&self) -> bool {
 529        match self {
 530            ExpandExcerptDirection::Up => false,
 531            ExpandExcerptDirection::Down => true,
 532            ExpandExcerptDirection::UpAndDown => true,
 533        }
 534    }
 535}
 536
 537#[derive(Clone, Debug, PartialEq)]
 538pub struct IndentGuide {
 539    pub buffer_id: BufferId,
 540    pub start_row: MultiBufferRow,
 541    pub end_row: MultiBufferRow,
 542    pub depth: u32,
 543    pub tab_size: u32,
 544    pub settings: IndentGuideSettings,
 545}
 546
 547impl IndentGuide {
 548    pub fn indent_level(&self) -> u32 {
 549        self.depth * self.tab_size
 550    }
 551}
 552
 553impl MultiBuffer {
 554    pub fn new(capability: Capability) -> Self {
 555        Self {
 556            snapshot: RefCell::new(MultiBufferSnapshot {
 557                show_headers: true,
 558                ..MultiBufferSnapshot::default()
 559            }),
 560            buffers: RefCell::default(),
 561            diffs: HashMap::default(),
 562            all_diff_hunks_expanded: false,
 563            subscriptions: Topic::default(),
 564            singleton: false,
 565            capability,
 566            title: None,
 567            buffers_by_path: Default::default(),
 568            history: History {
 569                next_transaction_id: clock::Lamport::default(),
 570                undo_stack: Vec::new(),
 571                redo_stack: Vec::new(),
 572                transaction_depth: 0,
 573                group_interval: Duration::from_millis(300),
 574            },
 575        }
 576    }
 577
 578    pub fn without_headers(capability: Capability) -> Self {
 579        Self {
 580            snapshot: Default::default(),
 581            buffers: Default::default(),
 582            buffers_by_path: Default::default(),
 583            diffs: HashMap::default(),
 584            all_diff_hunks_expanded: false,
 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            all_diff_hunks_expanded: self.all_diff_hunks_expanded,
 626            subscriptions: Default::default(),
 627            singleton: self.singleton,
 628            capability: self.capability,
 629            history: self.history.clone(),
 630            title: self.title.clone(),
 631        }
 632    }
 633
 634    pub fn with_title(mut self, title: String) -> Self {
 635        self.title = Some(title);
 636        self
 637    }
 638
 639    pub fn read_only(&self) -> bool {
 640        self.capability == Capability::ReadOnly
 641    }
 642
 643    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 644        let mut this = Self::new(buffer.read(cx).capability());
 645        this.singleton = true;
 646        this.push_excerpts(
 647            buffer,
 648            [ExcerptRange {
 649                context: text::Anchor::MIN..text::Anchor::MAX,
 650                primary: None,
 651            }],
 652            cx,
 653        );
 654        this.snapshot.borrow_mut().singleton = true;
 655        this
 656    }
 657
 658    /// Returns an up-to-date snapshot of the MultiBuffer.
 659    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 660        self.sync(cx);
 661        self.snapshot.borrow().clone()
 662    }
 663
 664    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 665        self.sync(cx);
 666        self.snapshot.borrow()
 667    }
 668
 669    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 670        if self.singleton {
 671            return Some(
 672                self.buffers
 673                    .borrow()
 674                    .values()
 675                    .next()
 676                    .unwrap()
 677                    .buffer
 678                    .clone(),
 679            );
 680        } else {
 681            None
 682        }
 683    }
 684
 685    pub fn is_singleton(&self) -> bool {
 686        self.singleton
 687    }
 688
 689    pub fn subscribe(&mut self) -> Subscription {
 690        self.subscriptions.subscribe()
 691    }
 692
 693    pub fn is_dirty(&self, cx: &App) -> bool {
 694        self.read(cx).is_dirty()
 695    }
 696
 697    pub fn has_deleted_file(&self, cx: &App) -> bool {
 698        self.read(cx).has_deleted_file()
 699    }
 700
 701    pub fn has_conflict(&self, cx: &App) -> bool {
 702        self.read(cx).has_conflict()
 703    }
 704
 705    // The `is_empty` signature doesn't match what clippy expects
 706    #[allow(clippy::len_without_is_empty)]
 707    pub fn len(&self, cx: &App) -> usize {
 708        self.read(cx).len()
 709    }
 710
 711    pub fn is_empty(&self) -> bool {
 712        self.buffers.borrow().is_empty()
 713    }
 714
 715    pub fn symbols_containing<T: ToOffset>(
 716        &self,
 717        offset: T,
 718        theme: Option<&SyntaxTheme>,
 719        cx: &App,
 720    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 721        self.read(cx).symbols_containing(offset, theme)
 722    }
 723
 724    pub fn edit<I, S, T>(
 725        &self,
 726        edits: I,
 727        autoindent_mode: Option<AutoindentMode>,
 728        cx: &mut Context<Self>,
 729    ) where
 730        I: IntoIterator<Item = (Range<S>, T)>,
 731        S: ToOffset,
 732        T: Into<Arc<str>>,
 733    {
 734        let snapshot = self.read(cx);
 735        let edits = edits
 736            .into_iter()
 737            .map(|(range, new_text)| {
 738                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 739                if range.start > range.end {
 740                    mem::swap(&mut range.start, &mut range.end);
 741                }
 742                (range, new_text.into())
 743            })
 744            .collect::<Vec<_>>();
 745
 746        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 747
 748        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 749        fn edit_internal(
 750            this: &MultiBuffer,
 751            snapshot: Ref<MultiBufferSnapshot>,
 752            edits: Vec<(Range<usize>, Arc<str>)>,
 753            mut autoindent_mode: Option<AutoindentMode>,
 754            cx: &mut Context<MultiBuffer>,
 755        ) {
 756            if this.read_only() || this.buffers.borrow().is_empty() {
 757                return;
 758            }
 759
 760            let original_start_columns = match &mut autoindent_mode {
 761                Some(AutoindentMode::Block {
 762                    original_start_columns,
 763                }) => mem::take(original_start_columns),
 764                _ => Default::default(),
 765            };
 766
 767            let (buffer_edits, edited_excerpt_ids) =
 768                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_start_columns);
 769            drop(snapshot);
 770
 771            let mut buffer_ids = Vec::new();
 772            for (buffer_id, mut edits) in buffer_edits {
 773                buffer_ids.push(buffer_id);
 774                edits.sort_by_key(|edit| edit.range.start);
 775                this.buffers.borrow()[&buffer_id]
 776                    .buffer
 777                    .update(cx, |buffer, cx| {
 778                        let mut edits = edits.into_iter().peekable();
 779                        let mut insertions = Vec::new();
 780                        let mut original_indent_columns = Vec::new();
 781                        let mut deletions = Vec::new();
 782                        let empty_str: Arc<str> = Arc::default();
 783                        while let Some(BufferEdit {
 784                            mut range,
 785                            mut new_text,
 786                            mut is_insertion,
 787                            original_start_column: original_indent_column,
 788                            excerpt_id,
 789                        }) = edits.next()
 790                        {
 791                            while let Some(BufferEdit {
 792                                range: next_range,
 793                                is_insertion: next_is_insertion,
 794                                new_text: next_new_text,
 795                                excerpt_id: next_excerpt_id,
 796                                ..
 797                            }) = edits.peek()
 798                            {
 799                                if range.end >= next_range.start {
 800                                    range.end = cmp::max(next_range.end, range.end);
 801                                    is_insertion |= *next_is_insertion;
 802                                    if excerpt_id == *next_excerpt_id {
 803                                        new_text = format!("{new_text}{next_new_text}").into();
 804                                    }
 805                                    edits.next();
 806                                } else {
 807                                    break;
 808                                }
 809                            }
 810
 811                            if is_insertion {
 812                                original_indent_columns.push(original_indent_column);
 813                                insertions.push((
 814                                    buffer.anchor_before(range.start)
 815                                        ..buffer.anchor_before(range.end),
 816                                    new_text.clone(),
 817                                ));
 818                            } else if !range.is_empty() {
 819                                deletions.push((
 820                                    buffer.anchor_before(range.start)
 821                                        ..buffer.anchor_before(range.end),
 822                                    empty_str.clone(),
 823                                ));
 824                            }
 825                        }
 826
 827                        let deletion_autoindent_mode =
 828                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 829                                Some(AutoindentMode::Block {
 830                                    original_start_columns: Default::default(),
 831                                })
 832                            } else {
 833                                autoindent_mode.clone()
 834                            };
 835                        let insertion_autoindent_mode =
 836                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 837                                Some(AutoindentMode::Block {
 838                                    original_start_columns: original_indent_columns,
 839                                })
 840                            } else {
 841                                autoindent_mode.clone()
 842                            };
 843
 844                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 845                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 846                    })
 847            }
 848
 849            cx.emit(Event::ExcerptsEdited {
 850                excerpt_ids: edited_excerpt_ids,
 851                buffer_ids,
 852            });
 853        }
 854    }
 855
 856    fn convert_edits_to_buffer_edits(
 857        &self,
 858        edits: Vec<(Range<usize>, Arc<str>)>,
 859        snapshot: &MultiBufferSnapshot,
 860        original_start_columns: &[u32],
 861    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 862        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 863        let mut edited_excerpt_ids = Vec::new();
 864        let mut cursor = snapshot.cursor::<usize>();
 865        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 866            let original_start_column = original_start_columns.get(ix).copied().unwrap_or(0);
 867
 868            cursor.seek(&range.start);
 869            let mut start_region = cursor.region().expect("start offset out of bounds");
 870            if !start_region.is_main_buffer {
 871                cursor.next();
 872                if let Some(region) = cursor.region() {
 873                    start_region = region;
 874                } else {
 875                    continue;
 876                }
 877            }
 878
 879            if range.end < start_region.range.start {
 880                continue;
 881            }
 882
 883            if range.end > start_region.range.end {
 884                cursor.seek_forward(&range.end);
 885            }
 886            let mut end_region = cursor.region().expect("end offset out of bounds");
 887            if !end_region.is_main_buffer {
 888                cursor.prev();
 889                if let Some(region) = cursor.region() {
 890                    end_region = region;
 891                } else {
 892                    continue;
 893                }
 894            }
 895
 896            if range.start > end_region.range.end {
 897                continue;
 898            }
 899
 900            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 901            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 902            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 903                .min(start_region.buffer_range.end);
 904            let buffer_end =
 905                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 906
 907            if start_region.excerpt.id == end_region.excerpt.id {
 908                if start_region.is_main_buffer {
 909                    edited_excerpt_ids.push(start_region.excerpt.id);
 910                    buffer_edits
 911                        .entry(start_region.buffer.remote_id())
 912                        .or_default()
 913                        .push(BufferEdit {
 914                            range: buffer_start..buffer_end,
 915                            new_text,
 916                            is_insertion: true,
 917                            original_start_column,
 918                            excerpt_id: start_region.excerpt.id,
 919                        });
 920                }
 921            } else {
 922                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 923                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 924                if start_region.is_main_buffer {
 925                    edited_excerpt_ids.push(start_region.excerpt.id);
 926                    buffer_edits
 927                        .entry(start_region.buffer.remote_id())
 928                        .or_default()
 929                        .push(BufferEdit {
 930                            range: start_excerpt_range,
 931                            new_text: new_text.clone(),
 932                            is_insertion: true,
 933                            original_start_column,
 934                            excerpt_id: start_region.excerpt.id,
 935                        });
 936                }
 937                if end_region.is_main_buffer {
 938                    edited_excerpt_ids.push(end_region.excerpt.id);
 939                    buffer_edits
 940                        .entry(end_region.buffer.remote_id())
 941                        .or_default()
 942                        .push(BufferEdit {
 943                            range: end_excerpt_range,
 944                            new_text: new_text.clone(),
 945                            is_insertion: false,
 946                            original_start_column,
 947                            excerpt_id: end_region.excerpt.id,
 948                        });
 949                }
 950
 951                cursor.seek(&range.start);
 952                cursor.next_excerpt();
 953                while let Some(region) = cursor.region() {
 954                    if region.excerpt.id == end_region.excerpt.id {
 955                        break;
 956                    }
 957                    if region.is_main_buffer {
 958                        edited_excerpt_ids.push(region.excerpt.id);
 959                        buffer_edits
 960                            .entry(region.buffer.remote_id())
 961                            .or_default()
 962                            .push(BufferEdit {
 963                                range: region.buffer_range,
 964                                new_text: new_text.clone(),
 965                                is_insertion: false,
 966                                original_start_column,
 967                                excerpt_id: region.excerpt.id,
 968                            });
 969                    }
 970                    cursor.next_excerpt();
 971                }
 972            }
 973        }
 974        (buffer_edits, edited_excerpt_ids)
 975    }
 976
 977    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 978    where
 979        I: IntoIterator<Item = Range<S>>,
 980        S: ToOffset,
 981    {
 982        let snapshot = self.read(cx);
 983        let empty = Arc::<str>::from("");
 984        let edits = ranges
 985            .into_iter()
 986            .map(|range| {
 987                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 988                if range.start > range.end {
 989                    mem::swap(&mut range.start, &mut range.end);
 990                }
 991                (range, empty.clone())
 992            })
 993            .collect::<Vec<_>>();
 994
 995        return autoindent_ranges_internal(self, snapshot, edits, cx);
 996
 997        fn autoindent_ranges_internal(
 998            this: &MultiBuffer,
 999            snapshot: Ref<MultiBufferSnapshot>,
1000            edits: Vec<(Range<usize>, Arc<str>)>,
1001            cx: &mut Context<MultiBuffer>,
1002        ) {
1003            if this.read_only() || this.buffers.borrow().is_empty() {
1004                return;
1005            }
1006
1007            let (buffer_edits, edited_excerpt_ids) =
1008                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1009            drop(snapshot);
1010
1011            let mut buffer_ids = Vec::new();
1012            for (buffer_id, mut edits) in buffer_edits {
1013                buffer_ids.push(buffer_id);
1014                edits.sort_unstable_by_key(|edit| edit.range.start);
1015
1016                let mut ranges: Vec<Range<usize>> = Vec::new();
1017                for edit in edits {
1018                    if let Some(last_range) = ranges.last_mut() {
1019                        if edit.range.start <= last_range.end {
1020                            last_range.end = last_range.end.max(edit.range.end);
1021                            continue;
1022                        }
1023                    }
1024                    ranges.push(edit.range);
1025                }
1026
1027                this.buffers.borrow()[&buffer_id]
1028                    .buffer
1029                    .update(cx, |buffer, cx| {
1030                        buffer.autoindent_ranges(ranges, cx);
1031                    })
1032            }
1033
1034            cx.emit(Event::ExcerptsEdited {
1035                excerpt_ids: edited_excerpt_ids,
1036                buffer_ids,
1037            });
1038        }
1039    }
1040
1041    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1042    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1043    // Panics if the given position is invalid.
1044    pub fn insert_empty_line(
1045        &mut self,
1046        position: impl ToPoint,
1047        space_above: bool,
1048        space_below: bool,
1049        cx: &mut Context<Self>,
1050    ) -> Point {
1051        let multibuffer_point = position.to_point(&self.read(cx));
1052        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1053        self.start_transaction(cx);
1054        let empty_line_start = buffer.update(cx, |buffer, cx| {
1055            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1056        });
1057        self.end_transaction(cx);
1058        multibuffer_point + (empty_line_start - buffer_point)
1059    }
1060
1061    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1062        self.start_transaction_at(Instant::now(), cx)
1063    }
1064
1065    pub fn start_transaction_at(
1066        &mut self,
1067        now: Instant,
1068        cx: &mut Context<Self>,
1069    ) -> Option<TransactionId> {
1070        if let Some(buffer) = self.as_singleton() {
1071            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1072        }
1073
1074        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1075            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1076        }
1077        self.history.start_transaction(now)
1078    }
1079
1080    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1081        self.end_transaction_at(Instant::now(), cx)
1082    }
1083
1084    pub fn end_transaction_at(
1085        &mut self,
1086        now: Instant,
1087        cx: &mut Context<Self>,
1088    ) -> Option<TransactionId> {
1089        if let Some(buffer) = self.as_singleton() {
1090            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1091        }
1092
1093        let mut buffer_transactions = HashMap::default();
1094        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1095            if let Some(transaction_id) =
1096                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1097            {
1098                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1099            }
1100        }
1101
1102        if self.history.end_transaction(now, buffer_transactions) {
1103            let transaction_id = self.history.group().unwrap();
1104            Some(transaction_id)
1105        } else {
1106            None
1107        }
1108    }
1109
1110    pub fn edited_ranges_for_transaction<D>(
1111        &self,
1112        transaction_id: TransactionId,
1113        cx: &App,
1114    ) -> Vec<Range<D>>
1115    where
1116        D: TextDimension + Ord + Sub<D, Output = D>,
1117    {
1118        let Some(transaction) = self.history.transaction(transaction_id) else {
1119            return Vec::new();
1120        };
1121
1122        let mut ranges = Vec::new();
1123        let snapshot = self.read(cx);
1124        let buffers = self.buffers.borrow();
1125        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1126
1127        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1128            let Some(buffer_state) = buffers.get(buffer_id) else {
1129                continue;
1130            };
1131
1132            let buffer = buffer_state.buffer.read(cx);
1133            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1134                for excerpt_id in &buffer_state.excerpts {
1135                    cursor.seek(excerpt_id, Bias::Left, &());
1136                    if let Some(excerpt) = cursor.item() {
1137                        if excerpt.locator == *excerpt_id {
1138                            let excerpt_buffer_start =
1139                                excerpt.range.context.start.summary::<D>(buffer);
1140                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1141                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1142                            if excerpt_range.contains(&range.start)
1143                                && excerpt_range.contains(&range.end)
1144                            {
1145                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1146
1147                                let mut start = excerpt_start;
1148                                start.add_assign(&(range.start - excerpt_buffer_start));
1149                                let mut end = excerpt_start;
1150                                end.add_assign(&(range.end - excerpt_buffer_start));
1151
1152                                ranges.push(start..end);
1153                                break;
1154                            }
1155                        }
1156                    }
1157                }
1158            }
1159        }
1160
1161        ranges.sort_by_key(|range| range.start);
1162        ranges
1163    }
1164
1165    pub fn merge_transactions(
1166        &mut self,
1167        transaction: TransactionId,
1168        destination: TransactionId,
1169        cx: &mut Context<Self>,
1170    ) {
1171        if let Some(buffer) = self.as_singleton() {
1172            buffer.update(cx, |buffer, _| {
1173                buffer.merge_transactions(transaction, destination)
1174            });
1175        } else if let Some(transaction) = self.history.forget(transaction) {
1176            if let Some(destination) = self.history.transaction_mut(destination) {
1177                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1178                    if let Some(destination_buffer_transaction_id) =
1179                        destination.buffer_transactions.get(&buffer_id)
1180                    {
1181                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1182                            state.buffer.update(cx, |buffer, _| {
1183                                buffer.merge_transactions(
1184                                    buffer_transaction_id,
1185                                    *destination_buffer_transaction_id,
1186                                )
1187                            });
1188                        }
1189                    } else {
1190                        destination
1191                            .buffer_transactions
1192                            .insert(buffer_id, buffer_transaction_id);
1193                    }
1194                }
1195            }
1196        }
1197    }
1198
1199    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1200        self.history.finalize_last_transaction();
1201        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1202            buffer.update(cx, |buffer, _| {
1203                buffer.finalize_last_transaction();
1204            });
1205        }
1206    }
1207
1208    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1209    where
1210        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1211    {
1212        self.history
1213            .push_transaction(buffer_transactions, Instant::now(), cx);
1214        self.history.finalize_last_transaction();
1215    }
1216
1217    pub fn group_until_transaction(
1218        &mut self,
1219        transaction_id: TransactionId,
1220        cx: &mut Context<Self>,
1221    ) {
1222        if let Some(buffer) = self.as_singleton() {
1223            buffer.update(cx, |buffer, _| {
1224                buffer.group_until_transaction(transaction_id)
1225            });
1226        } else {
1227            self.history.group_until(transaction_id);
1228        }
1229    }
1230
1231    pub fn set_active_selections(
1232        &self,
1233        selections: &[Selection<Anchor>],
1234        line_mode: bool,
1235        cursor_shape: CursorShape,
1236        cx: &mut Context<Self>,
1237    ) {
1238        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1239            Default::default();
1240        let snapshot = self.read(cx);
1241        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1242        for selection in selections {
1243            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1244            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1245
1246            cursor.seek(&Some(start_locator), Bias::Left, &());
1247            while let Some(excerpt) = cursor.item() {
1248                if excerpt.locator > *end_locator {
1249                    break;
1250                }
1251
1252                let mut start = excerpt.range.context.start;
1253                let mut end = excerpt.range.context.end;
1254                if excerpt.id == selection.start.excerpt_id {
1255                    start = selection.start.text_anchor;
1256                }
1257                if excerpt.id == selection.end.excerpt_id {
1258                    end = selection.end.text_anchor;
1259                }
1260                selections_by_buffer
1261                    .entry(excerpt.buffer_id)
1262                    .or_default()
1263                    .push(Selection {
1264                        id: selection.id,
1265                        start,
1266                        end,
1267                        reversed: selection.reversed,
1268                        goal: selection.goal,
1269                    });
1270
1271                cursor.next(&());
1272            }
1273        }
1274
1275        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1276            if !selections_by_buffer.contains_key(buffer_id) {
1277                buffer_state
1278                    .buffer
1279                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1280            }
1281        }
1282
1283        for (buffer_id, mut selections) in selections_by_buffer {
1284            self.buffers.borrow()[&buffer_id]
1285                .buffer
1286                .update(cx, |buffer, cx| {
1287                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1288                    let mut selections = selections.into_iter().peekable();
1289                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1290                        let mut selection = selections.next()?;
1291                        while let Some(next_selection) = selections.peek() {
1292                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1293                                let next_selection = selections.next().unwrap();
1294                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1295                                    selection.end = next_selection.end;
1296                                }
1297                            } else {
1298                                break;
1299                            }
1300                        }
1301                        Some(selection)
1302                    }));
1303                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1304                });
1305        }
1306    }
1307
1308    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1309        for buffer in self.buffers.borrow().values() {
1310            buffer
1311                .buffer
1312                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1313        }
1314    }
1315
1316    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1317        let mut transaction_id = None;
1318        if let Some(buffer) = self.as_singleton() {
1319            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1320        } else {
1321            while let Some(transaction) = self.history.pop_undo() {
1322                let mut undone = false;
1323                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1324                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1325                        undone |= buffer.update(cx, |buffer, cx| {
1326                            let undo_to = *buffer_transaction_id;
1327                            if let Some(entry) = buffer.peek_undo_stack() {
1328                                *buffer_transaction_id = entry.transaction_id();
1329                            }
1330                            buffer.undo_to_transaction(undo_to, cx)
1331                        });
1332                    }
1333                }
1334
1335                if undone {
1336                    transaction_id = Some(transaction.id);
1337                    break;
1338                }
1339            }
1340        }
1341
1342        if let Some(transaction_id) = transaction_id {
1343            cx.emit(Event::TransactionUndone { transaction_id });
1344        }
1345
1346        transaction_id
1347    }
1348
1349    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1350        if let Some(buffer) = self.as_singleton() {
1351            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1352        }
1353
1354        while let Some(transaction) = self.history.pop_redo() {
1355            let mut redone = false;
1356            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1357                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1358                    redone |= buffer.update(cx, |buffer, cx| {
1359                        let redo_to = *buffer_transaction_id;
1360                        if let Some(entry) = buffer.peek_redo_stack() {
1361                            *buffer_transaction_id = entry.transaction_id();
1362                        }
1363                        buffer.redo_to_transaction(redo_to, cx)
1364                    });
1365                }
1366            }
1367
1368            if redone {
1369                return Some(transaction.id);
1370            }
1371        }
1372
1373        None
1374    }
1375
1376    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1377        if let Some(buffer) = self.as_singleton() {
1378            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1379        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1380            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1381                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1382                    buffer.update(cx, |buffer, cx| {
1383                        buffer.undo_transaction(*transaction_id, cx)
1384                    });
1385                }
1386            }
1387        }
1388    }
1389
1390    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1391        if let Some(buffer) = self.as_singleton() {
1392            buffer.update(cx, |buffer, _| {
1393                buffer.forget_transaction(transaction_id);
1394            });
1395        } else if let Some(transaction) = self.history.forget(transaction_id) {
1396            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1397                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1398                    state.buffer.update(cx, |buffer, _| {
1399                        buffer.forget_transaction(buffer_transaction_id);
1400                    });
1401                }
1402            }
1403        }
1404    }
1405
1406    pub fn push_excerpts<O>(
1407        &mut self,
1408        buffer: Entity<Buffer>,
1409        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1410        cx: &mut Context<Self>,
1411    ) -> Vec<ExcerptId>
1412    where
1413        O: text::ToOffset,
1414    {
1415        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1416    }
1417
1418    pub fn push_excerpts_with_context_lines<O>(
1419        &mut self,
1420        buffer: Entity<Buffer>,
1421        ranges: Vec<Range<O>>,
1422        context_line_count: u32,
1423        cx: &mut Context<Self>,
1424    ) -> Vec<Range<Anchor>>
1425    where
1426        O: text::ToPoint + text::ToOffset,
1427    {
1428        let buffer_id = buffer.read(cx).remote_id();
1429        let buffer_snapshot = buffer.read(cx).snapshot();
1430        let (excerpt_ranges, range_counts) =
1431            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1432
1433        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1434
1435        let mut anchor_ranges = Vec::new();
1436        let mut ranges = ranges.into_iter();
1437        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1438            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1439                let start = Anchor {
1440                    buffer_id: Some(buffer_id),
1441                    excerpt_id,
1442                    text_anchor: buffer_snapshot.anchor_after(range.start),
1443                    diff_base_anchor: None,
1444                };
1445                let end = Anchor {
1446                    buffer_id: Some(buffer_id),
1447                    excerpt_id,
1448                    text_anchor: buffer_snapshot.anchor_after(range.end),
1449                    diff_base_anchor: None,
1450                };
1451                start..end
1452            }))
1453        }
1454        anchor_ranges
1455    }
1456
1457    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1458        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1459        let snapshot = self.snapshot(cx);
1460        let excerpt = snapshot.excerpt(*excerpt_id)?;
1461        Some(Anchor::in_buffer(
1462            *excerpt_id,
1463            excerpt.buffer_id,
1464            excerpt.range.context.start,
1465        ))
1466    }
1467
1468    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1469        self.buffers_by_path.keys()
1470    }
1471
1472    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1473    pub fn set_excerpts_for_path(
1474        &mut self,
1475        path: PathKey,
1476        buffer: Entity<Buffer>,
1477        ranges: Vec<Range<Point>>,
1478        context_line_count: u32,
1479        cx: &mut Context<Self>,
1480    ) -> bool {
1481        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1482
1483        let mut insert_after = self
1484            .buffers_by_path
1485            .range(..path.clone())
1486            .next_back()
1487            .map(|(_, value)| *value.last().unwrap())
1488            .unwrap_or(ExcerptId::min());
1489        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1490
1491        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1492
1493        let mut new_iter = new.into_iter().peekable();
1494        let mut existing_iter = existing.into_iter().peekable();
1495
1496        let mut new_excerpt_ids = Vec::new();
1497        let mut to_remove = Vec::new();
1498        let mut to_insert = Vec::new();
1499        let mut added_a_new_excerpt = false;
1500        let snapshot = self.snapshot(cx);
1501
1502        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1503        excerpts_cursor.next(&());
1504
1505        loop {
1506            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1507                (Some(new), Some(existing)) => (new, existing),
1508                (None, None) => break,
1509                (None, Some(_)) => {
1510                    to_remove.push(existing_iter.next().unwrap());
1511                    continue;
1512                }
1513                (Some(_), None) => {
1514                    added_a_new_excerpt = true;
1515                    to_insert.push(new_iter.next().unwrap());
1516                    continue;
1517                }
1518            };
1519            let locator = snapshot.excerpt_locator_for_id(*existing);
1520            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1521            let existing_excerpt = excerpts_cursor.item().unwrap();
1522            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1523                to_remove.push(existing_iter.next().unwrap());
1524                to_insert.push(new_iter.next().unwrap());
1525                continue;
1526            }
1527
1528            let existing_start = existing_excerpt
1529                .range
1530                .context
1531                .start
1532                .to_point(&buffer_snapshot);
1533            let existing_end = existing_excerpt
1534                .range
1535                .context
1536                .end
1537                .to_point(&buffer_snapshot);
1538
1539            if existing_end < new.context.start {
1540                to_remove.push(existing_iter.next().unwrap());
1541                continue;
1542            } else if existing_start > new.context.end {
1543                to_insert.push(new_iter.next().unwrap());
1544                continue;
1545            }
1546
1547            // maybe merge overlapping excerpts?
1548            // it's hard to distinguish between a manually expanded excerpt, and one that
1549            // got smaller because of a missing diff.
1550            if existing_start == new.context.start && existing_end == new.context.end {
1551                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1552                    insert_after,
1553                    buffer.clone(),
1554                    mem::take(&mut to_insert),
1555                    cx,
1556                ));
1557                insert_after = existing_iter.next().unwrap();
1558                new_excerpt_ids.push(insert_after);
1559                new_iter.next();
1560            } else {
1561                to_remove.push(existing_iter.next().unwrap());
1562                to_insert.push(new_iter.next().unwrap());
1563            }
1564        }
1565
1566        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1567            insert_after,
1568            buffer,
1569            to_insert,
1570            cx,
1571        ));
1572        self.remove_excerpts(to_remove, cx);
1573        if new_excerpt_ids.is_empty() {
1574            self.buffers_by_path.remove(&path);
1575        } else {
1576            self.buffers_by_path.insert(path, new_excerpt_ids);
1577        }
1578
1579        added_a_new_excerpt
1580    }
1581
1582    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1583        self.buffers_by_path.keys().cloned()
1584    }
1585
1586    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1587        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1588            self.remove_excerpts(to_remove, cx)
1589        }
1590    }
1591
1592    pub fn push_multiple_excerpts_with_context_lines(
1593        &self,
1594        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1595        context_line_count: u32,
1596        cx: &mut Context<Self>,
1597    ) -> Task<Vec<Range<Anchor>>> {
1598        use futures::StreamExt;
1599
1600        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1601
1602        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1603
1604        for (buffer, ranges) in buffers_with_ranges {
1605            let (buffer_id, buffer_snapshot) =
1606                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1607
1608            buffer_ids.push(buffer_id);
1609
1610            cx.background_spawn({
1611                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1612
1613                async move {
1614                    let (excerpt_ranges, counts) =
1615                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1616                    excerpt_ranges_tx
1617                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1618                        .await
1619                        .ok();
1620                }
1621            })
1622            .detach()
1623        }
1624
1625        cx.spawn(move |this, mut cx| async move {
1626            let mut results_by_buffer_id = HashMap::default();
1627            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1628                excerpt_ranges_rx.next().await
1629            {
1630                results_by_buffer_id
1631                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1632            }
1633
1634            let mut multi_buffer_ranges = Vec::default();
1635            'outer: for buffer_id in buffer_ids {
1636                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1637                    results_by_buffer_id.remove(&buffer_id)
1638                else {
1639                    continue;
1640                };
1641
1642                let mut ranges = ranges.into_iter();
1643                let mut range_counts = range_counts.into_iter();
1644                for excerpt_ranges in excerpt_ranges.chunks(100) {
1645                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1646                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1647                    }) {
1648                        Ok(excerpt_ids) => excerpt_ids,
1649                        Err(_) => continue 'outer,
1650                    };
1651
1652                    for (excerpt_id, range_count) in
1653                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1654                    {
1655                        for range in ranges.by_ref().take(range_count) {
1656                            let start = Anchor {
1657                                buffer_id: Some(buffer_id),
1658                                excerpt_id,
1659                                text_anchor: range.start,
1660                                diff_base_anchor: None,
1661                            };
1662                            let end = Anchor {
1663                                buffer_id: Some(buffer_id),
1664                                excerpt_id,
1665                                text_anchor: range.end,
1666                                diff_base_anchor: None,
1667                            };
1668                            multi_buffer_ranges.push(start..end);
1669                        }
1670                    }
1671                }
1672            }
1673
1674            multi_buffer_ranges
1675        })
1676    }
1677
1678    pub fn insert_excerpts_after<O>(
1679        &mut self,
1680        prev_excerpt_id: ExcerptId,
1681        buffer: Entity<Buffer>,
1682        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1683        cx: &mut Context<Self>,
1684    ) -> Vec<ExcerptId>
1685    where
1686        O: text::ToOffset,
1687    {
1688        let mut ids = Vec::new();
1689        let mut next_excerpt_id =
1690            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1691                last_entry.id.0 + 1
1692            } else {
1693                1
1694            };
1695        self.insert_excerpts_with_ids_after(
1696            prev_excerpt_id,
1697            buffer,
1698            ranges.into_iter().map(|range| {
1699                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1700                ids.push(id);
1701                (id, range)
1702            }),
1703            cx,
1704        );
1705        ids
1706    }
1707
1708    pub fn insert_excerpts_with_ids_after<O>(
1709        &mut self,
1710        prev_excerpt_id: ExcerptId,
1711        buffer: Entity<Buffer>,
1712        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1713        cx: &mut Context<Self>,
1714    ) where
1715        O: text::ToOffset,
1716    {
1717        assert_eq!(self.history.transaction_depth, 0);
1718        let mut ranges = ranges.into_iter().peekable();
1719        if ranges.peek().is_none() {
1720            return Default::default();
1721        }
1722
1723        self.sync(cx);
1724
1725        let buffer_id = buffer.read(cx).remote_id();
1726        let buffer_snapshot = buffer.read(cx).snapshot();
1727
1728        let mut buffers = self.buffers.borrow_mut();
1729        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1730            last_version: buffer_snapshot.version().clone(),
1731            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1732            excerpts: Default::default(),
1733            _subscriptions: [
1734                cx.observe(&buffer, |_, _, cx| cx.notify()),
1735                cx.subscribe(&buffer, Self::on_buffer_event),
1736            ],
1737            buffer: buffer.clone(),
1738        });
1739
1740        let mut snapshot = self.snapshot.borrow_mut();
1741
1742        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1743        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1744        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1745        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1746        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1747
1748        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1749        new_excerpts.update_last(
1750            |excerpt| {
1751                excerpt.has_trailing_newline = true;
1752            },
1753            &(),
1754        );
1755
1756        let next_locator = if let Some(excerpt) = cursor.item() {
1757            excerpt.locator.clone()
1758        } else {
1759            Locator::max()
1760        };
1761
1762        let mut excerpts = Vec::new();
1763        while let Some((id, range)) = ranges.next() {
1764            let locator = Locator::between(&prev_locator, &next_locator);
1765            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1766                buffer_state.excerpts.insert(ix, locator.clone());
1767            }
1768            let range = ExcerptRange {
1769                context: buffer_snapshot.anchor_before(&range.context.start)
1770                    ..buffer_snapshot.anchor_after(&range.context.end),
1771                primary: range.primary.map(|primary| {
1772                    buffer_snapshot.anchor_before(&primary.start)
1773                        ..buffer_snapshot.anchor_after(&primary.end)
1774                }),
1775            };
1776            excerpts.push((id, range.clone()));
1777            let excerpt = Excerpt::new(
1778                id,
1779                locator.clone(),
1780                buffer_id,
1781                buffer_snapshot.clone(),
1782                range,
1783                ranges.peek().is_some() || cursor.item().is_some(),
1784            );
1785            new_excerpts.push(excerpt, &());
1786            prev_locator = locator.clone();
1787
1788            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1789                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1790            }
1791            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1792        }
1793
1794        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1795
1796        let suffix = cursor.suffix(&());
1797        let changed_trailing_excerpt = suffix.is_empty();
1798        new_excerpts.append(suffix, &());
1799        drop(cursor);
1800        snapshot.excerpts = new_excerpts;
1801        snapshot.excerpt_ids = new_excerpt_ids;
1802        if changed_trailing_excerpt {
1803            snapshot.trailing_excerpt_update_count += 1;
1804        }
1805
1806        self.sync_diff_transforms(
1807            &mut snapshot,
1808            vec![Edit {
1809                old: edit_start..edit_start,
1810                new: edit_start..edit_end,
1811            }],
1812            DiffChangeKind::BufferEdited,
1813        );
1814        cx.emit(Event::Edited {
1815            singleton_buffer_edited: false,
1816            edited_buffer: None,
1817        });
1818        cx.emit(Event::ExcerptsAdded {
1819            buffer,
1820            predecessor: prev_excerpt_id,
1821            excerpts,
1822        });
1823        cx.notify();
1824    }
1825
1826    pub fn clear(&mut self, cx: &mut Context<Self>) {
1827        self.sync(cx);
1828        let ids = self.excerpt_ids();
1829        self.buffers.borrow_mut().clear();
1830        let mut snapshot = self.snapshot.borrow_mut();
1831        let start = ExcerptOffset::new(0);
1832        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1833        snapshot.excerpts = Default::default();
1834        snapshot.trailing_excerpt_update_count += 1;
1835        snapshot.is_dirty = false;
1836        snapshot.has_deleted_file = false;
1837        snapshot.has_conflict = false;
1838
1839        self.sync_diff_transforms(
1840            &mut snapshot,
1841            vec![Edit {
1842                old: start..prev_len,
1843                new: start..start,
1844            }],
1845            DiffChangeKind::BufferEdited,
1846        );
1847        cx.emit(Event::Edited {
1848            singleton_buffer_edited: false,
1849            edited_buffer: None,
1850        });
1851        cx.emit(Event::ExcerptsRemoved { ids });
1852        cx.notify();
1853    }
1854
1855    pub fn excerpts_for_buffer(
1856        &self,
1857        buffer_id: BufferId,
1858        cx: &App,
1859    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1860        let mut excerpts = Vec::new();
1861        let snapshot = self.read(cx);
1862        let buffers = self.buffers.borrow();
1863        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1864        for locator in buffers
1865            .get(&buffer_id)
1866            .map(|state| &state.excerpts)
1867            .into_iter()
1868            .flatten()
1869        {
1870            cursor.seek_forward(&Some(locator), Bias::Left, &());
1871            if let Some(excerpt) = cursor.item() {
1872                if excerpt.locator == *locator {
1873                    excerpts.push((excerpt.id, excerpt.range.clone()));
1874                }
1875            }
1876        }
1877
1878        excerpts
1879    }
1880
1881    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1882        let snapshot = self.read(cx);
1883        let buffers = self.buffers.borrow();
1884        let mut excerpts = snapshot
1885            .excerpts
1886            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1887        let mut diff_transforms = snapshot
1888            .diff_transforms
1889            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1890        diff_transforms.next(&());
1891        let locators = buffers
1892            .get(&buffer_id)
1893            .into_iter()
1894            .flat_map(|state| &state.excerpts);
1895        let mut result = Vec::new();
1896        for locator in locators {
1897            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1898            if let Some(excerpt) = excerpts.item() {
1899                if excerpt.locator == *locator {
1900                    let excerpt_start = excerpts.start().1.clone();
1901                    let excerpt_end =
1902                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1903
1904                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1905                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1906                    let start = diff_transforms.start().1 .0 + overshoot;
1907
1908                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1909                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1910                    let end = diff_transforms.start().1 .0 + overshoot;
1911
1912                    result.push(start..end)
1913                }
1914            }
1915        }
1916        result
1917    }
1918
1919    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1920        self.snapshot
1921            .borrow()
1922            .excerpts
1923            .iter()
1924            .map(|entry| entry.buffer_id)
1925            .collect()
1926    }
1927
1928    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1929        self.snapshot
1930            .borrow()
1931            .excerpts
1932            .iter()
1933            .map(|entry| entry.id)
1934            .collect()
1935    }
1936
1937    pub fn excerpt_containing(
1938        &self,
1939        position: impl ToOffset,
1940        cx: &App,
1941    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1942        let snapshot = self.read(cx);
1943        let offset = position.to_offset(&snapshot);
1944
1945        let mut cursor = snapshot.cursor::<usize>();
1946        cursor.seek(&offset);
1947        cursor
1948            .excerpt()
1949            .or_else(|| snapshot.excerpts.last())
1950            .map(|excerpt| {
1951                (
1952                    excerpt.id,
1953                    self.buffers
1954                        .borrow()
1955                        .get(&excerpt.buffer_id)
1956                        .unwrap()
1957                        .buffer
1958                        .clone(),
1959                    excerpt.range.context.clone(),
1960                )
1961            })
1962    }
1963
1964    // If point is at the end of the buffer, the last excerpt is returned
1965    pub fn point_to_buffer_offset<T: ToOffset>(
1966        &self,
1967        point: T,
1968        cx: &App,
1969    ) -> Option<(Entity<Buffer>, usize)> {
1970        let snapshot = self.read(cx);
1971        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1972        Some((
1973            self.buffers
1974                .borrow()
1975                .get(&buffer.remote_id())?
1976                .buffer
1977                .clone(),
1978            offset,
1979        ))
1980    }
1981
1982    // If point is at the end of the buffer, the last excerpt is returned
1983    pub fn point_to_buffer_point<T: ToPoint>(
1984        &self,
1985        point: T,
1986        cx: &App,
1987    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1988        let snapshot = self.read(cx);
1989        let point = point.to_point(&snapshot);
1990        let mut cursor = snapshot.cursor::<Point>();
1991        cursor.seek(&point);
1992
1993        cursor.region().and_then(|region| {
1994            if !region.is_main_buffer {
1995                return None;
1996            }
1997
1998            let overshoot = point - region.range.start;
1999            let buffer_point = region.buffer_range.start + overshoot;
2000            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
2001                .buffer
2002                .clone();
2003            Some((buffer, buffer_point, region.excerpt.id))
2004        })
2005    }
2006
2007    pub fn buffer_point_to_anchor(
2008        &self,
2009        buffer: &Entity<Buffer>,
2010        point: Point,
2011        cx: &App,
2012    ) -> Option<Anchor> {
2013        let mut found = None;
2014        let snapshot = buffer.read(cx).snapshot();
2015        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2016            let start = range.context.start.to_point(&snapshot);
2017            let end = range.context.end.to_point(&snapshot);
2018            if start <= point && point < end {
2019                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2020                break;
2021            }
2022            if point < start {
2023                found = Some((start, excerpt_id));
2024            }
2025            if point > end {
2026                found = Some((end, excerpt_id));
2027            }
2028        }
2029
2030        found.map(|(point, excerpt_id)| {
2031            let text_anchor = snapshot.anchor_after(point);
2032            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2033        })
2034    }
2035
2036    pub fn remove_excerpts(
2037        &mut self,
2038        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2039        cx: &mut Context<Self>,
2040    ) {
2041        self.sync(cx);
2042        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2043        if ids.is_empty() {
2044            return;
2045        }
2046
2047        let mut buffers = self.buffers.borrow_mut();
2048        let mut snapshot = self.snapshot.borrow_mut();
2049        let mut new_excerpts = SumTree::default();
2050        let mut cursor = snapshot
2051            .excerpts
2052            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2053        let mut edits = Vec::new();
2054        let mut excerpt_ids = ids.iter().copied().peekable();
2055
2056        while let Some(excerpt_id) = excerpt_ids.next() {
2057            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2058            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2059            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2060
2061            if let Some(mut excerpt) = cursor.item() {
2062                if excerpt.id != excerpt_id {
2063                    continue;
2064                }
2065                let mut old_start = cursor.start().1;
2066
2067                // Skip over the removed excerpt.
2068                'remove_excerpts: loop {
2069                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2070                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2071                        if buffer_state.excerpts.is_empty() {
2072                            buffers.remove(&excerpt.buffer_id);
2073                        }
2074                    }
2075                    cursor.next(&());
2076
2077                    // Skip over any subsequent excerpts that are also removed.
2078                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2079                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2080                        if let Some(next_excerpt) = cursor.item() {
2081                            if next_excerpt.locator == *next_locator {
2082                                excerpt_ids.next();
2083                                excerpt = next_excerpt;
2084                                continue 'remove_excerpts;
2085                            }
2086                        }
2087                    }
2088
2089                    break;
2090                }
2091
2092                // When removing the last excerpt, remove the trailing newline from
2093                // the previous excerpt.
2094                if cursor.item().is_none() && old_start.value > 0 {
2095                    old_start.value -= 1;
2096                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2097                }
2098
2099                // Push an edit for the removal of this run of excerpts.
2100                let old_end = cursor.start().1;
2101                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2102                edits.push(Edit {
2103                    old: old_start..old_end,
2104                    new: new_start..new_start,
2105                });
2106            }
2107        }
2108        let suffix = cursor.suffix(&());
2109        let changed_trailing_excerpt = suffix.is_empty();
2110        new_excerpts.append(suffix, &());
2111        drop(cursor);
2112        snapshot.excerpts = new_excerpts;
2113
2114        if changed_trailing_excerpt {
2115            snapshot.trailing_excerpt_update_count += 1;
2116        }
2117
2118        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2119        cx.emit(Event::Edited {
2120            singleton_buffer_edited: false,
2121            edited_buffer: None,
2122        });
2123        cx.emit(Event::ExcerptsRemoved { ids });
2124        cx.notify();
2125    }
2126
2127    pub fn wait_for_anchors<'a>(
2128        &self,
2129        anchors: impl 'a + Iterator<Item = Anchor>,
2130        cx: &mut Context<Self>,
2131    ) -> impl 'static + Future<Output = Result<()>> {
2132        let borrow = self.buffers.borrow();
2133        let mut error = None;
2134        let mut futures = Vec::new();
2135        for anchor in anchors {
2136            if let Some(buffer_id) = anchor.buffer_id {
2137                if let Some(buffer) = borrow.get(&buffer_id) {
2138                    buffer.buffer.update(cx, |buffer, _| {
2139                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2140                    });
2141                } else {
2142                    error = Some(anyhow!(
2143                        "buffer {buffer_id} is not part of this multi-buffer"
2144                    ));
2145                    break;
2146                }
2147            }
2148        }
2149        async move {
2150            if let Some(error) = error {
2151                Err(error)?;
2152            }
2153            for future in futures {
2154                future.await?;
2155            }
2156            Ok(())
2157        }
2158    }
2159
2160    pub fn text_anchor_for_position<T: ToOffset>(
2161        &self,
2162        position: T,
2163        cx: &App,
2164    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2165        let snapshot = self.read(cx);
2166        let anchor = snapshot.anchor_before(position);
2167        let buffer = self
2168            .buffers
2169            .borrow()
2170            .get(&anchor.buffer_id?)?
2171            .buffer
2172            .clone();
2173        Some((buffer, anchor.text_anchor))
2174    }
2175
2176    fn on_buffer_event(
2177        &mut self,
2178        buffer: Entity<Buffer>,
2179        event: &language::BufferEvent,
2180        cx: &mut Context<Self>,
2181    ) {
2182        cx.emit(match event {
2183            language::BufferEvent::Edited => Event::Edited {
2184                singleton_buffer_edited: true,
2185                edited_buffer: Some(buffer.clone()),
2186            },
2187            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2188            language::BufferEvent::Saved => Event::Saved,
2189            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2190            language::BufferEvent::Reloaded => Event::Reloaded,
2191            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2192            language::BufferEvent::LanguageChanged => {
2193                Event::LanguageChanged(buffer.read(cx).remote_id())
2194            }
2195            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2196            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2197            language::BufferEvent::Closed => Event::Closed,
2198            language::BufferEvent::Discarded => Event::Discarded,
2199            language::BufferEvent::CapabilityChanged => {
2200                self.capability = buffer.read(cx).capability();
2201                Event::CapabilityChanged
2202            }
2203            language::BufferEvent::Operation { .. } => return,
2204        });
2205    }
2206
2207    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2208        self.sync(cx);
2209        let mut snapshot = self.snapshot.borrow_mut();
2210        let diff = diff.read(cx);
2211        let buffer_id = diff.buffer_id;
2212        let diff = diff.snapshot(cx);
2213        snapshot.diffs.insert(buffer_id, diff);
2214    }
2215
2216    fn buffer_diff_changed(
2217        &mut self,
2218        diff: Entity<BufferDiff>,
2219        range: Range<text::Anchor>,
2220        cx: &mut Context<Self>,
2221    ) {
2222        self.sync(cx);
2223
2224        let diff = diff.read(cx);
2225        let buffer_id = diff.buffer_id;
2226        let buffers = self.buffers.borrow();
2227        let Some(buffer_state) = buffers.get(&buffer_id) else {
2228            return;
2229        };
2230
2231        let buffer = buffer_state.buffer.read(cx);
2232        let diff_change_range = range.to_offset(buffer);
2233
2234        let mut new_diff = diff.snapshot(cx);
2235        if new_diff.base_text().is_none() && self.all_diff_hunks_expanded {
2236            let secondary_diff_insertion = new_diff
2237                .secondary_diff()
2238                .map_or(true, |secondary_diff| secondary_diff.base_text().is_none());
2239            new_diff = BufferDiff::build_with_single_insertion(
2240                secondary_diff_insertion,
2241                buffer.snapshot(),
2242                cx,
2243            );
2244        }
2245
2246        let mut snapshot = self.snapshot.borrow_mut();
2247        let base_text_changed = snapshot
2248            .diffs
2249            .get(&buffer_id)
2250            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2251
2252        snapshot.diffs.insert(buffer_id, new_diff);
2253
2254        let mut excerpt_edits = Vec::new();
2255        for locator in &buffer_state.excerpts {
2256            let mut cursor = snapshot
2257                .excerpts
2258                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2259            cursor.seek_forward(&Some(locator), Bias::Left, &());
2260            if let Some(excerpt) = cursor.item() {
2261                if excerpt.locator == *locator {
2262                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2263                    if diff_change_range.end < excerpt_buffer_range.start
2264                        || diff_change_range.start > excerpt_buffer_range.end
2265                    {
2266                        continue;
2267                    }
2268                    let excerpt_start = cursor.start().1;
2269                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2270                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2271                        diff_change_range
2272                            .start
2273                            .saturating_sub(excerpt_buffer_range.start),
2274                    );
2275                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2276                        diff_change_range
2277                            .end
2278                            .saturating_sub(excerpt_buffer_range.start),
2279                    );
2280                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2281                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2282                    excerpt_edits.push(Edit {
2283                        old: edit_start..edit_end,
2284                        new: edit_start..edit_end,
2285                    });
2286                }
2287            }
2288        }
2289
2290        self.sync_diff_transforms(
2291            &mut snapshot,
2292            excerpt_edits,
2293            DiffChangeKind::DiffUpdated {
2294                base_changed: base_text_changed,
2295            },
2296        );
2297        cx.emit(Event::Edited {
2298            singleton_buffer_edited: false,
2299            edited_buffer: None,
2300        });
2301    }
2302
2303    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2304        self.buffers
2305            .borrow()
2306            .values()
2307            .map(|state| state.buffer.clone())
2308            .collect()
2309    }
2310
2311    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2312        self.buffers
2313            .borrow()
2314            .get(&buffer_id)
2315            .map(|state| state.buffer.clone())
2316    }
2317
2318    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2319        self.point_to_buffer_offset(point, cx)
2320            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2321    }
2322
2323    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2324        let mut language = None;
2325        let mut file = None;
2326        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2327            let buffer = buffer.read(cx);
2328            language = buffer.language_at(offset);
2329            file = buffer.file();
2330        }
2331        language_settings(language.map(|l| l.name()), file, cx)
2332    }
2333
2334    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2335        self.buffers
2336            .borrow()
2337            .values()
2338            .for_each(|state| f(&state.buffer))
2339    }
2340
2341    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2342        if let Some(title) = self.title.as_ref() {
2343            return title.into();
2344        }
2345
2346        if let Some(buffer) = self.as_singleton() {
2347            if let Some(file) = buffer.read(cx).file() {
2348                return file.file_name(cx).to_string_lossy();
2349            }
2350        }
2351
2352        "untitled".into()
2353    }
2354
2355    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2356        self.title = Some(title);
2357        cx.notify();
2358    }
2359
2360    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2361    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2362        for buffer_state in self.buffers.borrow().values() {
2363            buffer_state
2364                .buffer
2365                .update(cx, |buffer, _cx| buffer.refresh_preview());
2366        }
2367    }
2368
2369    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2370    pub fn preserve_preview(&self, cx: &App) -> bool {
2371        self.buffers
2372            .borrow()
2373            .values()
2374            .all(|state| state.buffer.read(cx).preserve_preview())
2375    }
2376
2377    #[cfg(any(test, feature = "test-support"))]
2378    pub fn is_parsing(&self, cx: &App) -> bool {
2379        self.as_singleton().unwrap().read(cx).is_parsing()
2380    }
2381
2382    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2383        let buffer_id = diff.read(cx).buffer_id;
2384        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2385        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2386    }
2387
2388    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2389        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2390    }
2391
2392    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2393        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2394    }
2395
2396    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2397        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2398    }
2399
2400    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2401        self.all_diff_hunks_expanded = true;
2402        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2403    }
2404
2405    pub fn all_diff_hunks_expanded(&self) -> bool {
2406        self.all_diff_hunks_expanded
2407    }
2408
2409    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2410        self.read(cx)
2411            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2412            .nth(1)
2413            .is_some()
2414    }
2415
2416    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2417        let snapshot = self.read(cx);
2418        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2419        let offset_range = range.to_offset(&snapshot);
2420        cursor.seek(&offset_range.start, Bias::Left, &());
2421        while let Some(item) = cursor.item() {
2422            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2423                break;
2424            }
2425            if item.hunk_info().is_some() {
2426                return true;
2427            }
2428            cursor.next(&());
2429        }
2430        false
2431    }
2432
2433    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2434        let snapshot = self.read(cx);
2435        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2436        for range in ranges {
2437            let range = range.to_point(&snapshot);
2438            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2439            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2440            let start = start.saturating_sub(1);
2441            let end = snapshot.len().min(end + 1);
2442            cursor.seek(&start, Bias::Right, &());
2443            while let Some(item) = cursor.item() {
2444                if *cursor.start() >= end {
2445                    break;
2446                }
2447                if item.hunk_info().is_some() {
2448                    return true;
2449                }
2450                cursor.next(&());
2451            }
2452        }
2453        false
2454    }
2455
2456    pub fn expand_or_collapse_diff_hunks_inner(
2457        &mut self,
2458        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2459        expand: bool,
2460        cx: &mut Context<Self>,
2461    ) {
2462        if self.all_diff_hunks_expanded && !expand {
2463            return;
2464        }
2465        self.sync(cx);
2466        let mut snapshot = self.snapshot.borrow_mut();
2467        let mut excerpt_edits = Vec::new();
2468        for (range, end_excerpt_id) in ranges {
2469            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2470                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2471                    continue;
2472                }
2473                let start = Anchor::in_buffer(
2474                    diff_hunk.excerpt_id,
2475                    diff_hunk.buffer_id,
2476                    diff_hunk.buffer_range.start,
2477                );
2478                let end = Anchor::in_buffer(
2479                    diff_hunk.excerpt_id,
2480                    diff_hunk.buffer_id,
2481                    diff_hunk.buffer_range.end,
2482                );
2483                let start = snapshot.excerpt_offset_for_anchor(&start);
2484                let end = snapshot.excerpt_offset_for_anchor(&end);
2485                excerpt_edits.push(text::Edit {
2486                    old: start..end,
2487                    new: start..end,
2488                });
2489            }
2490        }
2491
2492        self.sync_diff_transforms(
2493            &mut snapshot,
2494            excerpt_edits,
2495            DiffChangeKind::ExpandOrCollapseHunks { expand },
2496        );
2497        cx.emit(Event::DiffHunksToggled);
2498        cx.emit(Event::Edited {
2499            singleton_buffer_edited: false,
2500            edited_buffer: None,
2501        });
2502    }
2503
2504    pub fn expand_or_collapse_diff_hunks(
2505        &mut self,
2506        ranges: Vec<Range<Anchor>>,
2507        expand: bool,
2508        cx: &mut Context<Self>,
2509    ) {
2510        let snapshot = self.snapshot.borrow().clone();
2511        let ranges = ranges.iter().map(move |range| {
2512            let end_excerpt_id = range.end.excerpt_id;
2513            let range = range.to_point(&snapshot);
2514            let mut peek_end = range.end;
2515            if range.end.row < snapshot.max_row().0 {
2516                peek_end = Point::new(range.end.row + 1, 0);
2517            };
2518            (range.start..peek_end, end_excerpt_id)
2519        });
2520        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2521    }
2522
2523    pub fn resize_excerpt(
2524        &mut self,
2525        id: ExcerptId,
2526        range: Range<text::Anchor>,
2527        cx: &mut Context<Self>,
2528    ) {
2529        self.sync(cx);
2530
2531        let mut snapshot = self.snapshot.borrow_mut();
2532        let locator = snapshot.excerpt_locator_for_id(id);
2533        let mut new_excerpts = SumTree::default();
2534        let mut cursor = snapshot
2535            .excerpts
2536            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2537        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2538
2539        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2540        new_excerpts.append(prefix, &());
2541
2542        let mut excerpt = cursor.item().unwrap().clone();
2543        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2544
2545        excerpt.range.context.start = range.start;
2546        excerpt.range.context.end = range.end;
2547        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2548
2549        excerpt.text_summary = excerpt
2550            .buffer
2551            .text_summary_for_range(excerpt.range.context.clone());
2552
2553        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2554        let old_start_offset = cursor.start().1;
2555        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2556        let edit = Edit {
2557            old: old_start_offset..old_start_offset + old_text_len,
2558            new: new_start_offset..new_start_offset + new_text_len,
2559        };
2560
2561        if let Some(last_edit) = edits.last_mut() {
2562            if last_edit.old.end == edit.old.start {
2563                last_edit.old.end = edit.old.end;
2564                last_edit.new.end = edit.new.end;
2565            } else {
2566                edits.push(edit);
2567            }
2568        } else {
2569            edits.push(edit);
2570        }
2571
2572        new_excerpts.push(excerpt, &());
2573
2574        cursor.next(&());
2575
2576        new_excerpts.append(cursor.suffix(&()), &());
2577
2578        drop(cursor);
2579        snapshot.excerpts = new_excerpts;
2580
2581        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2582        cx.emit(Event::Edited {
2583            singleton_buffer_edited: false,
2584            edited_buffer: None,
2585        });
2586        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2587        cx.notify();
2588    }
2589
2590    pub fn expand_excerpts(
2591        &mut self,
2592        ids: impl IntoIterator<Item = ExcerptId>,
2593        line_count: u32,
2594        direction: ExpandExcerptDirection,
2595        cx: &mut Context<Self>,
2596    ) {
2597        if line_count == 0 {
2598            return;
2599        }
2600        self.sync(cx);
2601        let mut snapshot = self.snapshot.borrow_mut();
2602
2603        let ids = ids.into_iter().collect::<Vec<_>>();
2604        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2605        let mut new_excerpts = SumTree::default();
2606        let mut cursor = snapshot
2607            .excerpts
2608            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2609        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2610
2611        for locator in &locators {
2612            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2613            new_excerpts.append(prefix, &());
2614
2615            let mut excerpt = cursor.item().unwrap().clone();
2616            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2617
2618            let up_line_count = if direction.should_expand_up() {
2619                line_count
2620            } else {
2621                0
2622            };
2623
2624            let start_row = excerpt
2625                .range
2626                .context
2627                .start
2628                .to_point(&excerpt.buffer)
2629                .row
2630                .saturating_sub(up_line_count);
2631            let start_point = Point::new(start_row, 0);
2632            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2633
2634            let down_line_count = if direction.should_expand_down() {
2635                line_count
2636            } else {
2637                0
2638            };
2639
2640            let mut end_point = excerpt.buffer.clip_point(
2641                excerpt.range.context.end.to_point(&excerpt.buffer)
2642                    + Point::new(down_line_count, 0),
2643                Bias::Left,
2644            );
2645            end_point.column = excerpt.buffer.line_len(end_point.row);
2646            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2647            excerpt.max_buffer_row = end_point.row;
2648
2649            excerpt.text_summary = excerpt
2650                .buffer
2651                .text_summary_for_range(excerpt.range.context.clone());
2652
2653            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2654            let old_start_offset = cursor.start().1;
2655            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2656            let edit = Edit {
2657                old: old_start_offset..old_start_offset + old_text_len,
2658                new: new_start_offset..new_start_offset + new_text_len,
2659            };
2660
2661            if let Some(last_edit) = edits.last_mut() {
2662                if last_edit.old.end == edit.old.start {
2663                    last_edit.old.end = edit.old.end;
2664                    last_edit.new.end = edit.new.end;
2665                } else {
2666                    edits.push(edit);
2667                }
2668            } else {
2669                edits.push(edit);
2670            }
2671
2672            new_excerpts.push(excerpt, &());
2673
2674            cursor.next(&());
2675        }
2676
2677        new_excerpts.append(cursor.suffix(&()), &());
2678
2679        drop(cursor);
2680        snapshot.excerpts = new_excerpts;
2681
2682        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2683        cx.emit(Event::Edited {
2684            singleton_buffer_edited: false,
2685            edited_buffer: None,
2686        });
2687        cx.emit(Event::ExcerptsExpanded { ids });
2688        cx.notify();
2689    }
2690
2691    fn sync(&self, cx: &App) {
2692        let mut snapshot = self.snapshot.borrow_mut();
2693        let mut excerpts_to_edit = Vec::new();
2694        let mut non_text_state_updated = false;
2695        let mut is_dirty = false;
2696        let mut has_deleted_file = false;
2697        let mut has_conflict = false;
2698        let mut edited = false;
2699        let mut buffers = self.buffers.borrow_mut();
2700        for buffer_state in buffers.values_mut() {
2701            let buffer = buffer_state.buffer.read(cx);
2702            let version = buffer.version();
2703            let non_text_state_update_count = buffer.non_text_state_update_count();
2704
2705            let buffer_edited = version.changed_since(&buffer_state.last_version);
2706            let buffer_non_text_state_updated =
2707                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2708            if buffer_edited || buffer_non_text_state_updated {
2709                buffer_state.last_version = version;
2710                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2711                excerpts_to_edit.extend(
2712                    buffer_state
2713                        .excerpts
2714                        .iter()
2715                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2716                );
2717            }
2718
2719            edited |= buffer_edited;
2720            non_text_state_updated |= buffer_non_text_state_updated;
2721            is_dirty |= buffer.is_dirty();
2722            has_deleted_file |= buffer
2723                .file()
2724                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2725            has_conflict |= buffer.has_conflict();
2726        }
2727        if edited {
2728            snapshot.edit_count += 1;
2729        }
2730        if non_text_state_updated {
2731            snapshot.non_text_state_update_count += 1;
2732        }
2733        snapshot.is_dirty = is_dirty;
2734        snapshot.has_deleted_file = has_deleted_file;
2735        snapshot.has_conflict = has_conflict;
2736
2737        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2738
2739        let mut edits = Vec::new();
2740        let mut new_excerpts = SumTree::default();
2741        let mut cursor = snapshot
2742            .excerpts
2743            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2744
2745        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2746            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2747            let old_excerpt = cursor.item().unwrap();
2748            let buffer = buffer.read(cx);
2749            let buffer_id = buffer.remote_id();
2750
2751            let mut new_excerpt;
2752            if buffer_edited {
2753                edits.extend(
2754                    buffer
2755                        .edits_since_in_range::<usize>(
2756                            old_excerpt.buffer.version(),
2757                            old_excerpt.range.context.clone(),
2758                        )
2759                        .map(|edit| {
2760                            let excerpt_old_start = cursor.start().1;
2761                            let excerpt_new_start =
2762                                ExcerptOffset::new(new_excerpts.summary().text.len);
2763                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2764                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2765                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2766                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2767                            Edit {
2768                                old: old_start..old_end,
2769                                new: new_start..new_end,
2770                            }
2771                        }),
2772                );
2773
2774                new_excerpt = Excerpt::new(
2775                    old_excerpt.id,
2776                    locator.clone(),
2777                    buffer_id,
2778                    buffer.snapshot(),
2779                    old_excerpt.range.clone(),
2780                    old_excerpt.has_trailing_newline,
2781                );
2782            } else {
2783                new_excerpt = old_excerpt.clone();
2784                new_excerpt.buffer = buffer.snapshot();
2785            }
2786
2787            new_excerpts.push(new_excerpt, &());
2788            cursor.next(&());
2789        }
2790        new_excerpts.append(cursor.suffix(&()), &());
2791
2792        drop(cursor);
2793        snapshot.excerpts = new_excerpts;
2794
2795        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2796    }
2797
2798    fn sync_diff_transforms(
2799        &self,
2800        snapshot: &mut MultiBufferSnapshot,
2801        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2802        change_kind: DiffChangeKind,
2803    ) {
2804        if excerpt_edits.is_empty() {
2805            return;
2806        }
2807
2808        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2809        let mut old_diff_transforms = snapshot
2810            .diff_transforms
2811            .cursor::<(ExcerptOffset, usize)>(&());
2812        let mut new_diff_transforms = SumTree::default();
2813        let mut old_expanded_hunks = HashSet::default();
2814        let mut output_edits = Vec::new();
2815        let mut output_delta = 0_isize;
2816        let mut at_transform_boundary = true;
2817        let mut end_of_current_insert = None;
2818
2819        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2820        while let Some(edit) = excerpt_edits.next() {
2821            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2822            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2823                excerpts.prev(&());
2824            }
2825
2826            // Keep any transforms that are before the edit.
2827            if at_transform_boundary {
2828                at_transform_boundary = false;
2829                let transforms_before_edit =
2830                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2831                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2832                if let Some(transform) = old_diff_transforms.item() {
2833                    if old_diff_transforms.end(&()).0 == edit.old.start
2834                        && old_diff_transforms.start().0 < edit.old.start
2835                    {
2836                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2837                        old_diff_transforms.next(&());
2838                    }
2839                }
2840            }
2841
2842            // Compute the start of the edit in output coordinates.
2843            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2844            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2845            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2846
2847            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2848                &edit,
2849                &mut excerpts,
2850                &mut old_diff_transforms,
2851                &mut new_diff_transforms,
2852                &mut end_of_current_insert,
2853                &mut old_expanded_hunks,
2854                &snapshot,
2855                change_kind,
2856            );
2857
2858            // Compute the end of the edit in output coordinates.
2859            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2860            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2861            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2862            let edit_new_end =
2863                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2864            let output_edit = Edit {
2865                old: edit_old_start..edit_old_end,
2866                new: edit_new_start..edit_new_end,
2867            };
2868
2869            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2870            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2871            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2872                output_edits.push(output_edit);
2873            }
2874
2875            // If this is the last edit that intersects the current diff transform,
2876            // then recreate the content up to the end of this transform, to prepare
2877            // for reusing additional slices of the old transforms.
2878            if excerpt_edits.peek().map_or(true, |next_edit| {
2879                next_edit.old.start >= old_diff_transforms.end(&()).0
2880            }) {
2881                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2882                    && match old_diff_transforms.item() {
2883                        Some(DiffTransform::BufferContent {
2884                            inserted_hunk_info: Some(hunk),
2885                            ..
2886                        }) => excerpts.item().is_some_and(|excerpt| {
2887                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2888                        }),
2889                        _ => true,
2890                    };
2891
2892                let mut excerpt_offset = edit.new.end;
2893                if !keep_next_old_transform {
2894                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2895                    old_diff_transforms.next(&());
2896                }
2897
2898                old_expanded_hunks.clear();
2899                self.push_buffer_content_transform(
2900                    &snapshot,
2901                    &mut new_diff_transforms,
2902                    excerpt_offset,
2903                    end_of_current_insert,
2904                );
2905                at_transform_boundary = true;
2906            }
2907        }
2908
2909        // Keep any transforms that are after the last edit.
2910        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2911
2912        // Ensure there's always at least one buffer content transform.
2913        if new_diff_transforms.is_empty() {
2914            new_diff_transforms.push(
2915                DiffTransform::BufferContent {
2916                    summary: Default::default(),
2917                    inserted_hunk_info: None,
2918                },
2919                &(),
2920            );
2921        }
2922
2923        self.subscriptions.publish(output_edits);
2924        drop(old_diff_transforms);
2925        drop(excerpts);
2926        snapshot.diff_transforms = new_diff_transforms;
2927        snapshot.edit_count += 1;
2928
2929        #[cfg(any(test, feature = "test-support"))]
2930        snapshot.check_invariants();
2931    }
2932
2933    #[allow(clippy::too_many_arguments)]
2934    fn recompute_diff_transforms_for_edit(
2935        &self,
2936        edit: &Edit<TypedOffset<Excerpt>>,
2937        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2938        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2939        new_diff_transforms: &mut SumTree<DiffTransform>,
2940        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2941        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2942        snapshot: &MultiBufferSnapshot,
2943        change_kind: DiffChangeKind,
2944    ) -> bool {
2945        log::trace!(
2946            "recomputing diff transform for edit {:?} => {:?}",
2947            edit.old.start.value..edit.old.end.value,
2948            edit.new.start.value..edit.new.end.value
2949        );
2950
2951        // Record which hunks were previously expanded.
2952        while let Some(item) = old_diff_transforms.item() {
2953            if let Some(hunk_info) = item.hunk_info() {
2954                log::trace!(
2955                    "previously expanded hunk at {}",
2956                    old_diff_transforms.start().0
2957                );
2958                old_expanded_hunks.insert(hunk_info);
2959            }
2960            if old_diff_transforms.end(&()).0 > edit.old.end {
2961                break;
2962            }
2963            old_diff_transforms.next(&());
2964        }
2965
2966        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2967        if old_expanded_hunks.is_empty()
2968            && change_kind == DiffChangeKind::BufferEdited
2969            && !self.all_diff_hunks_expanded
2970        {
2971            return false;
2972        }
2973
2974        // Visit each excerpt that intersects the edit.
2975        let mut did_expand_hunks = false;
2976        while let Some(excerpt) = excerpts.item() {
2977            // Recompute the expanded hunks in the portion of the excerpt that
2978            // intersects the edit.
2979            if let Some((diff, base_text)) = snapshot
2980                .diffs
2981                .get(&excerpt.buffer_id)
2982                .and_then(|diff| Some((diff, diff.base_text()?)))
2983            {
2984                let buffer = &excerpt.buffer;
2985                let excerpt_start = *excerpts.start();
2986                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2987                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2988                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2989                let edit_buffer_start =
2990                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2991                let edit_buffer_end =
2992                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2993                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2994                let edit_anchor_range =
2995                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2996
2997                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2998                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2999
3000                    let hunk_info = DiffTransformHunkInfo {
3001                        excerpt_id: excerpt.id,
3002                        hunk_start_anchor: hunk.buffer_range.start,
3003                        hunk_secondary_status: hunk.secondary_status,
3004                    };
3005                    if hunk_buffer_range.start < excerpt_buffer_start {
3006                        log::trace!("skipping hunk that starts before excerpt");
3007                        continue;
3008                    }
3009
3010                    let hunk_excerpt_start = excerpt_start
3011                        + ExcerptOffset::new(
3012                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3013                        );
3014                    let hunk_excerpt_end = excerpt_end.min(
3015                        excerpt_start
3016                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3017                    );
3018
3019                    self.push_buffer_content_transform(
3020                        snapshot,
3021                        new_diff_transforms,
3022                        hunk_excerpt_start,
3023                        *end_of_current_insert,
3024                    );
3025
3026                    // For every existing hunk, determine if it was previously expanded
3027                    // and if it should currently be expanded.
3028                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3029                    let should_expand_hunk = match &change_kind {
3030                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3031                            self.all_diff_hunks_expanded || was_previously_expanded
3032                        }
3033                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3034                            let intersects = hunk_buffer_range.is_empty()
3035                                || hunk_buffer_range.end > edit_buffer_start;
3036                            if *expand {
3037                                intersects
3038                                    || was_previously_expanded
3039                                    || self.all_diff_hunks_expanded
3040                            } else {
3041                                !intersects
3042                                    && (was_previously_expanded || self.all_diff_hunks_expanded)
3043                            }
3044                        }
3045                        _ => was_previously_expanded || self.all_diff_hunks_expanded,
3046                    };
3047
3048                    if should_expand_hunk {
3049                        did_expand_hunks = true;
3050                        log::trace!(
3051                            "expanding hunk {:?}, excerpt:{:?}",
3052                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3053                            excerpt.id
3054                        );
3055
3056                        if !hunk.diff_base_byte_range.is_empty()
3057                            && hunk_buffer_range.start >= edit_buffer_start
3058                            && hunk_buffer_range.start <= excerpt_buffer_end
3059                        {
3060                            let mut text_cursor =
3061                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3062                            let mut base_text_summary =
3063                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3064
3065                            let mut has_trailing_newline = false;
3066                            if base_text_summary.last_line_chars > 0 {
3067                                base_text_summary += TextSummary::newline();
3068                                has_trailing_newline = true;
3069                            }
3070
3071                            new_diff_transforms.push(
3072                                DiffTransform::DeletedHunk {
3073                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3074                                    summary: base_text_summary,
3075                                    buffer_id: excerpt.buffer_id,
3076                                    hunk_info,
3077                                    has_trailing_newline,
3078                                },
3079                                &(),
3080                            );
3081                        }
3082
3083                        if !hunk_buffer_range.is_empty() {
3084                            *end_of_current_insert =
3085                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3086                        }
3087                    }
3088                }
3089            }
3090
3091            if excerpts.end(&()) <= edit.new.end {
3092                excerpts.next(&());
3093            } else {
3094                break;
3095            }
3096        }
3097
3098        did_expand_hunks || !old_expanded_hunks.is_empty()
3099    }
3100
3101    fn append_diff_transforms(
3102        &self,
3103        new_transforms: &mut SumTree<DiffTransform>,
3104        subtree: SumTree<DiffTransform>,
3105    ) {
3106        if let Some(DiffTransform::BufferContent {
3107            inserted_hunk_info,
3108            summary,
3109        }) = subtree.first()
3110        {
3111            if self.extend_last_buffer_content_transform(
3112                new_transforms,
3113                *inserted_hunk_info,
3114                *summary,
3115            ) {
3116                let mut cursor = subtree.cursor::<()>(&());
3117                cursor.next(&());
3118                cursor.next(&());
3119                new_transforms.append(cursor.suffix(&()), &());
3120                return;
3121            }
3122        }
3123        new_transforms.append(subtree, &());
3124    }
3125
3126    fn push_diff_transform(
3127        &self,
3128        new_transforms: &mut SumTree<DiffTransform>,
3129        transform: DiffTransform,
3130    ) {
3131        if let DiffTransform::BufferContent {
3132            inserted_hunk_info: inserted_hunk_anchor,
3133            summary,
3134        } = transform
3135        {
3136            if self.extend_last_buffer_content_transform(
3137                new_transforms,
3138                inserted_hunk_anchor,
3139                summary,
3140            ) {
3141                return;
3142            }
3143        }
3144        new_transforms.push(transform, &());
3145    }
3146
3147    fn push_buffer_content_transform(
3148        &self,
3149        old_snapshot: &MultiBufferSnapshot,
3150        new_transforms: &mut SumTree<DiffTransform>,
3151        end_offset: ExcerptOffset,
3152        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3153    ) {
3154        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3155            (end_offset.min(insertion_end_offset), Some(hunk_info))
3156        });
3157        let unchanged_region = [(end_offset, None)];
3158
3159        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3160        {
3161            let start_offset = new_transforms.summary().excerpt_len();
3162            if end_offset <= start_offset {
3163                continue;
3164            }
3165            let summary_to_add = old_snapshot
3166                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3167
3168            if !self.extend_last_buffer_content_transform(
3169                new_transforms,
3170                inserted_hunk_info,
3171                summary_to_add,
3172            ) {
3173                new_transforms.push(
3174                    DiffTransform::BufferContent {
3175                        summary: summary_to_add,
3176                        inserted_hunk_info,
3177                    },
3178                    &(),
3179                )
3180            }
3181        }
3182    }
3183
3184    fn extend_last_buffer_content_transform(
3185        &self,
3186        new_transforms: &mut SumTree<DiffTransform>,
3187        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3188        summary_to_add: TextSummary,
3189    ) -> bool {
3190        let mut did_extend = false;
3191        new_transforms.update_last(
3192            |last_transform| {
3193                if let DiffTransform::BufferContent {
3194                    summary,
3195                    inserted_hunk_info: inserted_hunk_anchor,
3196                } = last_transform
3197                {
3198                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3199                        *summary += summary_to_add;
3200                        did_extend = true;
3201                    }
3202                }
3203            },
3204            &(),
3205        );
3206        did_extend
3207    }
3208}
3209
3210#[cfg(any(test, feature = "test-support"))]
3211impl MultiBuffer {
3212    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3213        let buffer = cx.new(|cx| Buffer::local(text, cx));
3214        cx.new(|cx| Self::singleton(buffer, cx))
3215    }
3216
3217    pub fn build_multi<const COUNT: usize>(
3218        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3219        cx: &mut gpui::App,
3220    ) -> Entity<Self> {
3221        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3222        for (text, ranges) in excerpts {
3223            let buffer = cx.new(|cx| Buffer::local(text, cx));
3224            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3225                context: range,
3226                primary: None,
3227            });
3228            multi.update(cx, |multi, cx| {
3229                multi.push_excerpts(buffer, excerpt_ranges, cx)
3230            });
3231        }
3232
3233        multi
3234    }
3235
3236    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3237        cx.new(|cx| Self::singleton(buffer, cx))
3238    }
3239
3240    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3241        cx.new(|cx| {
3242            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3243            let mutation_count = rng.gen_range(1..=5);
3244            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3245            multibuffer
3246        })
3247    }
3248
3249    pub fn randomly_edit(
3250        &mut self,
3251        rng: &mut impl rand::Rng,
3252        edit_count: usize,
3253        cx: &mut Context<Self>,
3254    ) {
3255        use util::RandomCharIter;
3256
3257        let snapshot = self.read(cx);
3258        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3259        let mut last_end = None;
3260        for _ in 0..edit_count {
3261            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3262                break;
3263            }
3264
3265            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3266            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3267            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3268            last_end = Some(end);
3269
3270            let mut range = start..end;
3271            if rng.gen_bool(0.2) {
3272                mem::swap(&mut range.start, &mut range.end);
3273            }
3274
3275            let new_text_len = rng.gen_range(0..10);
3276            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3277
3278            edits.push((range, new_text.into()));
3279        }
3280        log::info!("mutating multi-buffer with {:?}", edits);
3281        drop(snapshot);
3282
3283        self.edit(edits, None, cx);
3284    }
3285
3286    pub fn randomly_edit_excerpts(
3287        &mut self,
3288        rng: &mut impl rand::Rng,
3289        mutation_count: usize,
3290        cx: &mut Context<Self>,
3291    ) {
3292        use rand::prelude::*;
3293        use std::env;
3294        use util::RandomCharIter;
3295
3296        let max_excerpts = env::var("MAX_EXCERPTS")
3297            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3298            .unwrap_or(5);
3299
3300        let mut buffers = Vec::new();
3301        for _ in 0..mutation_count {
3302            if rng.gen_bool(0.05) {
3303                log::info!("Clearing multi-buffer");
3304                self.clear(cx);
3305                continue;
3306            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3307                let ids = self.excerpt_ids();
3308                let mut excerpts = HashSet::default();
3309                for _ in 0..rng.gen_range(0..ids.len()) {
3310                    excerpts.extend(ids.choose(rng).copied());
3311                }
3312
3313                let line_count = rng.gen_range(0..5);
3314
3315                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3316
3317                self.expand_excerpts(
3318                    excerpts.iter().cloned(),
3319                    line_count,
3320                    ExpandExcerptDirection::UpAndDown,
3321                    cx,
3322                );
3323                continue;
3324            }
3325
3326            let excerpt_ids = self.excerpt_ids();
3327            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3328                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3329                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3330                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3331                    let buffer = buffers.last().unwrap().read(cx);
3332                    log::info!(
3333                        "Creating new buffer {} with text: {:?}",
3334                        buffer.remote_id(),
3335                        buffer.text()
3336                    );
3337                    buffers.last().unwrap().clone()
3338                } else {
3339                    self.buffers
3340                        .borrow()
3341                        .values()
3342                        .choose(rng)
3343                        .unwrap()
3344                        .buffer
3345                        .clone()
3346                };
3347
3348                let buffer = buffer_handle.read(cx);
3349                let buffer_text = buffer.text();
3350                let ranges = (0..rng.gen_range(0..5))
3351                    .map(|_| {
3352                        let end_ix =
3353                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3354                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3355                        ExcerptRange {
3356                            context: start_ix..end_ix,
3357                            primary: None,
3358                        }
3359                    })
3360                    .collect::<Vec<_>>();
3361                log::info!(
3362                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3363                    buffer_handle.read(cx).remote_id(),
3364                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3365                    ranges
3366                        .iter()
3367                        .map(|r| &buffer_text[r.context.clone()])
3368                        .collect::<Vec<_>>()
3369                );
3370
3371                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3372                log::info!("Inserted with ids: {:?}", excerpt_id);
3373            } else {
3374                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3375                let mut excerpts_to_remove = excerpt_ids
3376                    .choose_multiple(rng, remove_count)
3377                    .cloned()
3378                    .collect::<Vec<_>>();
3379                let snapshot = self.snapshot.borrow();
3380                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3381                drop(snapshot);
3382                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3383                self.remove_excerpts(excerpts_to_remove, cx);
3384            }
3385        }
3386    }
3387
3388    pub fn randomly_mutate(
3389        &mut self,
3390        rng: &mut impl rand::Rng,
3391        mutation_count: usize,
3392        cx: &mut Context<Self>,
3393    ) {
3394        use rand::prelude::*;
3395
3396        if rng.gen_bool(0.7) || self.singleton {
3397            let buffer = self
3398                .buffers
3399                .borrow()
3400                .values()
3401                .choose(rng)
3402                .map(|state| state.buffer.clone());
3403
3404            if let Some(buffer) = buffer {
3405                buffer.update(cx, |buffer, cx| {
3406                    if rng.gen() {
3407                        buffer.randomly_edit(rng, mutation_count, cx);
3408                    } else {
3409                        buffer.randomly_undo_redo(rng, cx);
3410                    }
3411                });
3412            } else {
3413                self.randomly_edit(rng, mutation_count, cx);
3414            }
3415        } else {
3416            self.randomly_edit_excerpts(rng, mutation_count, cx);
3417        }
3418
3419        self.check_invariants(cx);
3420    }
3421
3422    fn check_invariants(&self, cx: &App) {
3423        self.read(cx).check_invariants();
3424    }
3425}
3426
3427impl EventEmitter<Event> for MultiBuffer {}
3428
3429impl MultiBufferSnapshot {
3430    pub fn text(&self) -> String {
3431        self.chunks(0..self.len(), false)
3432            .map(|chunk| chunk.text)
3433            .collect()
3434    }
3435
3436    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3437        self.reversed_chunks_in_range(0..position.to_offset(self))
3438            .flat_map(|c| c.chars().rev())
3439    }
3440
3441    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3442        let mut cursor = self.cursor::<usize>();
3443        cursor.seek(&range.end);
3444        let current_chunks = cursor.region().as_ref().map(|region| {
3445            let start_overshoot = range.start.saturating_sub(region.range.start);
3446            let end_overshoot = range.end - region.range.start;
3447            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3448            let start = region.buffer_range.start + start_overshoot;
3449            region.buffer.reversed_chunks_in_range(start..end)
3450        });
3451        ReversedMultiBufferChunks {
3452            cursor,
3453            current_chunks,
3454            start: range.start,
3455            offset: range.end,
3456        }
3457    }
3458
3459    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3460        let offset = position.to_offset(self);
3461        self.text_for_range(offset..self.len())
3462            .flat_map(|chunk| chunk.chars())
3463    }
3464
3465    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3466        self.chunks(range, false).map(|chunk| chunk.text)
3467    }
3468
3469    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3470        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3471            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3472    }
3473
3474    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3475    where
3476        T: ToOffset,
3477    {
3478        let position = position.to_offset(self);
3479        position == self.clip_offset(position, Bias::Left)
3480            && self
3481                .bytes_in_range(position..self.len())
3482                .flatten()
3483                .copied()
3484                .take(needle.len())
3485                .eq(needle.bytes())
3486    }
3487
3488    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3489        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3490    }
3491
3492    pub fn diff_hunks_in_range<T: ToPoint>(
3493        &self,
3494        range: Range<T>,
3495    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3496        let query_range = range.start.to_point(self)..range.end.to_point(self);
3497        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3498            let diff = self.diffs.get(&buffer.remote_id())?;
3499            let buffer_start = buffer.anchor_before(buffer_range.start);
3500            let buffer_end = buffer.anchor_after(buffer_range.end);
3501            Some(
3502                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3503                    .map(|hunk| {
3504                        (
3505                            Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
3506                            hunk,
3507                        )
3508                    }),
3509            )
3510        })
3511        .filter_map(move |(range, hunk, excerpt)| {
3512            if range.start != range.end
3513                && range.end == query_range.start
3514                && !hunk.row_range.is_empty()
3515            {
3516                return None;
3517            }
3518            let end_row = if range.end.column == 0 {
3519                range.end.row
3520            } else {
3521                range.end.row + 1
3522            };
3523            Some(MultiBufferDiffHunk {
3524                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3525                buffer_id: excerpt.buffer_id,
3526                excerpt_id: excerpt.id,
3527                buffer_range: hunk.buffer_range.clone(),
3528                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3529                secondary_status: hunk.secondary_status,
3530            })
3531        })
3532    }
3533
3534    pub fn excerpt_ids_for_range<T: ToOffset>(
3535        &self,
3536        range: Range<T>,
3537    ) -> impl Iterator<Item = ExcerptId> + '_ {
3538        let range = range.start.to_offset(self)..range.end.to_offset(self);
3539        let mut cursor = self.cursor::<usize>();
3540        cursor.seek(&range.start);
3541        std::iter::from_fn(move || {
3542            let region = cursor.region()?;
3543            if region.range.start >= range.end {
3544                return None;
3545            }
3546            cursor.next_excerpt();
3547            Some(region.excerpt.id)
3548        })
3549    }
3550
3551    pub fn buffer_ids_for_range<T: ToOffset>(
3552        &self,
3553        range: Range<T>,
3554    ) -> impl Iterator<Item = BufferId> + '_ {
3555        let range = range.start.to_offset(self)..range.end.to_offset(self);
3556        let mut cursor = self.cursor::<usize>();
3557        cursor.seek(&range.start);
3558        std::iter::from_fn(move || {
3559            let region = cursor.region()?;
3560            if region.range.start >= range.end {
3561                return None;
3562            }
3563            cursor.next_excerpt();
3564            Some(region.excerpt.buffer_id)
3565        })
3566    }
3567
3568    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3569        &self,
3570        ranges: impl Iterator<Item = Range<T>>,
3571    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3572        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3573    }
3574
3575    pub fn range_to_buffer_ranges<T: ToOffset>(
3576        &self,
3577        range: Range<T>,
3578    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3579        let start = range.start.to_offset(&self);
3580        let end = range.end.to_offset(&self);
3581
3582        let mut cursor = self.cursor::<usize>();
3583        cursor.seek(&start);
3584
3585        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3586        while let Some(region) = cursor.region() {
3587            if region.range.start > end {
3588                break;
3589            }
3590            if region.is_main_buffer {
3591                let start_overshoot = start.saturating_sub(region.range.start);
3592                let end_overshoot = end.saturating_sub(region.range.start);
3593                let start = region
3594                    .buffer_range
3595                    .end
3596                    .min(region.buffer_range.start + start_overshoot);
3597                let end = region
3598                    .buffer_range
3599                    .end
3600                    .min(region.buffer_range.start + end_overshoot);
3601                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3602                    *excerpt_id == region.excerpt.id && prev_range.end == start
3603                }) {
3604                    prev.1.end = end;
3605                } else {
3606                    result.push((region.buffer, start..end, region.excerpt.id));
3607                }
3608            }
3609            cursor.next();
3610        }
3611        result
3612    }
3613
3614    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3615        &self,
3616        range: Range<T>,
3617    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3618        let start = range.start.to_offset(&self);
3619        let end = range.end.to_offset(&self);
3620
3621        let mut cursor = self.cursor::<usize>();
3622        cursor.seek(&start);
3623
3624        std::iter::from_fn(move || {
3625            let region = cursor.region()?;
3626            if region.range.start > end {
3627                return None;
3628            }
3629            let start_overshoot = start.saturating_sub(region.range.start);
3630            let end_overshoot = end.saturating_sub(region.range.start);
3631            let start = region
3632                .buffer_range
3633                .end
3634                .min(region.buffer_range.start + start_overshoot);
3635            let end = region
3636                .buffer_range
3637                .end
3638                .min(region.buffer_range.start + end_overshoot);
3639
3640            let region_excerpt_id = region.excerpt.id;
3641            let deleted_hunk_anchor = if region.is_main_buffer {
3642                None
3643            } else {
3644                Some(self.anchor_before(region.range.start))
3645            };
3646            let result = (
3647                region.buffer,
3648                start..end,
3649                region_excerpt_id,
3650                deleted_hunk_anchor,
3651            );
3652            cursor.next();
3653            Some(result)
3654        })
3655    }
3656
3657    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3658    /// coordinates.
3659    ///
3660    /// The given callback will be called for every excerpt intersecting the given range. It will
3661    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3662    /// The callback should return an iterator of metadata items from that buffer, each paired
3663    /// with a buffer range.
3664    ///
3665    /// The returned iterator yields each of these metadata items, paired with its range in
3666    /// multi-buffer coordinates.
3667    fn lift_buffer_metadata<'a, D, M, I>(
3668        &'a self,
3669        query_range: Range<D>,
3670        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3671    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3672    where
3673        I: Iterator<Item = (Range<D>, M)> + 'a,
3674        D: TextDimension + Ord + Sub<D, Output = D>,
3675    {
3676        let max_position = D::from_text_summary(&self.text_summary());
3677        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3678        let mut cursor = self.cursor::<D>();
3679
3680        // Find the excerpt and buffer offset where the given range ends.
3681        cursor.seek(&query_range.end);
3682        let mut range_end = None;
3683        while let Some(region) = cursor.region() {
3684            if region.is_main_buffer {
3685                let mut buffer_end = region.buffer_range.start;
3686                let overshoot = if query_range.end > region.range.start {
3687                    query_range.end - region.range.start
3688                } else {
3689                    D::default()
3690                };
3691                buffer_end.add_assign(&overshoot);
3692                range_end = Some((region.excerpt.id, buffer_end));
3693                break;
3694            }
3695            cursor.next();
3696        }
3697
3698        cursor.seek(&query_range.start);
3699
3700        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3701            if region.range.start > D::zero(&()) {
3702                cursor.prev()
3703            }
3704        }
3705
3706        iter::from_fn(move || loop {
3707            let excerpt = cursor.excerpt()?;
3708
3709            // If we have already retrieved metadata for this excerpt, continue to use it.
3710            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3711                .as_mut()
3712                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3713            {
3714                Some(metadata)
3715            }
3716            // Otherwise, compute the intersection of the input range with the excerpt's range,
3717            // and retrieve the metadata for the resulting range.
3718            else {
3719                let region = cursor.region()?;
3720                let mut buffer_start;
3721                if region.is_main_buffer {
3722                    buffer_start = region.buffer_range.start;
3723                    if query_range.start > region.range.start {
3724                        let overshoot = query_range.start - region.range.start;
3725                        buffer_start.add_assign(&overshoot);
3726                    }
3727                    buffer_start = buffer_start.min(region.buffer_range.end);
3728                } else {
3729                    buffer_start = cursor.main_buffer_position()?;
3730                };
3731                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3732                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3733                    if excerpt.id == end_excerpt_id {
3734                        buffer_end = buffer_end.min(end_buffer_offset);
3735                    }
3736                }
3737
3738                if let Some(iterator) =
3739                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3740                {
3741                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3742                } else {
3743                    None
3744                }
3745            };
3746
3747            // Visit each metadata item.
3748            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3749            {
3750                // Find the multibuffer regions that contain the start and end of
3751                // the metadata item's range.
3752                if metadata_buffer_range.start > D::default() {
3753                    while let Some(region) = cursor.region() {
3754                        if region.is_main_buffer
3755                            && (region.buffer_range.end >= metadata_buffer_range.start
3756                                || cursor.is_at_end_of_excerpt())
3757                        {
3758                            break;
3759                        }
3760                        cursor.next();
3761                    }
3762                }
3763                let start_region = cursor.region()?;
3764                while let Some(region) = cursor.region() {
3765                    if region.is_main_buffer
3766                        && (region.buffer_range.end > metadata_buffer_range.end
3767                            || cursor.is_at_end_of_excerpt())
3768                    {
3769                        break;
3770                    }
3771                    cursor.next();
3772                }
3773                let end_region = cursor.region();
3774
3775                // Convert the metadata item's range into multibuffer coordinates.
3776                let mut start_position = start_region.range.start;
3777                let region_buffer_start = start_region.buffer_range.start;
3778                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3779                {
3780                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3781                    start_position = start_position.min(start_region.range.end);
3782                }
3783
3784                let mut end_position = max_position;
3785                if let Some(end_region) = &end_region {
3786                    end_position = end_region.range.start;
3787                    debug_assert!(end_region.is_main_buffer);
3788                    let region_buffer_start = end_region.buffer_range.start;
3789                    if metadata_buffer_range.end > region_buffer_start {
3790                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3791                    }
3792                    end_position = end_position.min(end_region.range.end);
3793                }
3794
3795                if start_position <= query_range.end && end_position >= query_range.start {
3796                    return Some((start_position..end_position, metadata, excerpt));
3797                }
3798            }
3799            // When there are no more metadata items for this excerpt, move to the next excerpt.
3800            else {
3801                current_excerpt_metadata.take();
3802                cursor.next_excerpt();
3803            }
3804        })
3805    }
3806
3807    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3808        let offset = position.to_offset(self);
3809
3810        // Go to the region containing the given offset.
3811        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3812        cursor.seek(&DimensionPair {
3813            key: offset,
3814            value: None,
3815        });
3816        let mut region = cursor.region()?;
3817        if region.range.start.key == offset || !region.is_main_buffer {
3818            cursor.prev();
3819            region = cursor.region()?;
3820        }
3821
3822        // Find the corresponding buffer offset.
3823        let overshoot = if region.is_main_buffer {
3824            offset - region.range.start.key
3825        } else {
3826            0
3827        };
3828        let mut max_buffer_offset = region
3829            .buffer
3830            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3831
3832        loop {
3833            let excerpt = cursor.excerpt()?;
3834            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3835            let buffer_offset = excerpt_end.min(max_buffer_offset);
3836            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3837            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3838
3839            if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3840                for hunk in diff.hunks_intersecting_range_rev(
3841                    excerpt.range.context.start..buffer_end,
3842                    &excerpt.buffer,
3843                ) {
3844                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3845                    if hunk.row_range.end >= buffer_end_row {
3846                        continue;
3847                    }
3848
3849                    let hunk_start = Point::new(hunk.row_range.start, 0);
3850                    let hunk_end = Point::new(hunk.row_range.end, 0);
3851
3852                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3853                        key: hunk_range.start,
3854                        value: None,
3855                    });
3856
3857                    let mut region = cursor.region()?;
3858                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3859                    {
3860                        cursor.prev();
3861                        region = cursor.region()?;
3862                    }
3863
3864                    let overshoot = if region.is_main_buffer {
3865                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3866                    } else {
3867                        Point::zero()
3868                    };
3869                    let start = region.range.start.value.unwrap() + overshoot;
3870
3871                    while let Some(region) = cursor.region() {
3872                        if !region.is_main_buffer
3873                            || region.buffer_range.end.value.unwrap() <= hunk_end
3874                        {
3875                            cursor.next();
3876                        } else {
3877                            break;
3878                        }
3879                    }
3880
3881                    let end = if let Some(region) = cursor.region() {
3882                        let overshoot = if region.is_main_buffer {
3883                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3884                        } else {
3885                            Point::zero()
3886                        };
3887                        region.range.start.value.unwrap() + overshoot
3888                    } else {
3889                        self.max_point()
3890                    };
3891
3892                    return Some(MultiBufferDiffHunk {
3893                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3894                        buffer_id: excerpt.buffer_id,
3895                        excerpt_id: excerpt.id,
3896                        buffer_range: hunk.buffer_range.clone(),
3897                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3898                        secondary_status: hunk.secondary_status,
3899                    });
3900                }
3901            }
3902
3903            cursor.prev_excerpt();
3904            max_buffer_offset = usize::MAX;
3905        }
3906    }
3907
3908    pub fn has_diff_hunks(&self) -> bool {
3909        self.diffs.values().any(|diff| !diff.is_empty())
3910    }
3911
3912    pub fn surrounding_word<T: ToOffset>(
3913        &self,
3914        start: T,
3915        for_completion: bool,
3916    ) -> (Range<usize>, Option<CharKind>) {
3917        let mut start = start.to_offset(self);
3918        let mut end = start;
3919        let mut next_chars = self.chars_at(start).peekable();
3920        let mut prev_chars = self.reversed_chars_at(start).peekable();
3921
3922        let classifier = self
3923            .char_classifier_at(start)
3924            .for_completion(for_completion);
3925
3926        let word_kind = cmp::max(
3927            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3928            next_chars.peek().copied().map(|c| classifier.kind(c)),
3929        );
3930
3931        for ch in prev_chars {
3932            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3933                start -= ch.len_utf8();
3934            } else {
3935                break;
3936            }
3937        }
3938
3939        for ch in next_chars {
3940            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3941                end += ch.len_utf8();
3942            } else {
3943                break;
3944            }
3945        }
3946
3947        (start..end, word_kind)
3948    }
3949
3950    pub fn is_singleton(&self) -> bool {
3951        self.singleton
3952    }
3953
3954    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3955        if self.singleton {
3956            self.excerpts
3957                .iter()
3958                .next()
3959                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3960        } else {
3961            None
3962        }
3963    }
3964
3965    pub fn len(&self) -> usize {
3966        self.diff_transforms.summary().output.len
3967    }
3968
3969    pub fn is_empty(&self) -> bool {
3970        self.excerpts.summary().text.len == 0
3971    }
3972
3973    pub fn widest_line_number(&self) -> u32 {
3974        self.excerpts.summary().widest_line_number + 1
3975    }
3976
3977    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3978        let range = range.start.to_offset(self)..range.end.to_offset(self);
3979        let mut excerpts = self.cursor::<usize>();
3980        excerpts.seek(&range.start);
3981
3982        let mut chunk;
3983        let mut has_trailing_newline;
3984        let excerpt_bytes;
3985        if let Some(region) = excerpts.region() {
3986            let mut bytes = region.buffer.bytes_in_range(
3987                region.buffer_range.start + range.start - region.range.start
3988                    ..(region.buffer_range.start + range.end - region.range.start)
3989                        .min(region.buffer_range.end),
3990            );
3991            chunk = bytes.next().unwrap_or(&[][..]);
3992            excerpt_bytes = Some(bytes);
3993            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3994            if chunk.is_empty() && has_trailing_newline {
3995                chunk = b"\n";
3996                has_trailing_newline = false;
3997            }
3998        } else {
3999            chunk = &[][..];
4000            excerpt_bytes = None;
4001            has_trailing_newline = false;
4002        };
4003
4004        MultiBufferBytes {
4005            range,
4006            cursor: excerpts,
4007            excerpt_bytes,
4008            has_trailing_newline,
4009            chunk,
4010        }
4011    }
4012
4013    pub fn reversed_bytes_in_range<T: ToOffset>(
4014        &self,
4015        range: Range<T>,
4016    ) -> ReversedMultiBufferBytes {
4017        let range = range.start.to_offset(self)..range.end.to_offset(self);
4018        let mut chunks = self.reversed_chunks_in_range(range.clone());
4019        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4020        ReversedMultiBufferBytes {
4021            range,
4022            chunks,
4023            chunk,
4024        }
4025    }
4026
4027    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4028        let mut cursor = self.cursor::<Point>();
4029        cursor.seek(&Point::new(start_row.0, 0));
4030        let mut result = MultiBufferRows {
4031            point: Point::new(0, 0),
4032            is_empty: self.excerpts.is_empty(),
4033            cursor,
4034        };
4035        result.seek(start_row);
4036        result
4037    }
4038
4039    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4040        let mut chunks = MultiBufferChunks {
4041            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4042            range: 0..0,
4043            excerpts: self.excerpts.cursor(&()),
4044            diff_transforms: self.diff_transforms.cursor(&()),
4045            diffs: &self.diffs,
4046            diff_base_chunks: None,
4047            excerpt_chunks: None,
4048            buffer_chunk: None,
4049            language_aware,
4050        };
4051        let range = range.start.to_offset(self)..range.end.to_offset(self);
4052        chunks.seek(range);
4053        chunks
4054    }
4055
4056    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4057        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4058    }
4059
4060    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4061        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4062    }
4063
4064    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4065        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4066    }
4067
4068    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4069        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4070            buffer.clip_point_utf16(Unclipped(point), bias)
4071        })
4072    }
4073
4074    pub fn offset_to_point(&self, offset: usize) -> Point {
4075        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4076    }
4077
4078    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4079        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4080    }
4081
4082    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4083        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4084    }
4085
4086    pub fn point_to_offset(&self, point: Point) -> usize {
4087        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4088    }
4089
4090    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4091        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4092    }
4093
4094    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4095        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4096    }
4097
4098    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4099        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4100    }
4101
4102    fn clip_dimension<D>(
4103        &self,
4104        position: D,
4105        bias: Bias,
4106        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4107    ) -> D
4108    where
4109        D: TextDimension + Ord + Sub<D, Output = D>,
4110    {
4111        let mut cursor = self.cursor();
4112        cursor.seek(&position);
4113        if let Some(region) = cursor.region() {
4114            if position >= region.range.end {
4115                return region.range.end;
4116            }
4117            let overshoot = position - region.range.start;
4118            let mut buffer_position = region.buffer_range.start;
4119            buffer_position.add_assign(&overshoot);
4120            let clipped_buffer_position =
4121                clip_buffer_position(&region.buffer, buffer_position, bias);
4122            let mut position = region.range.start;
4123            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4124            position
4125        } else {
4126            D::from_text_summary(&self.text_summary())
4127        }
4128    }
4129
4130    fn convert_dimension<D1, D2>(
4131        &self,
4132        key: D1,
4133        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4134    ) -> D2
4135    where
4136        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4137        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4138    {
4139        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4140        cursor.seek(&DimensionPair { key, value: None });
4141        if let Some(region) = cursor.region() {
4142            if key >= region.range.end.key {
4143                return region.range.end.value.unwrap();
4144            }
4145            let start_key = region.range.start.key;
4146            let start_value = region.range.start.value.unwrap();
4147            let buffer_start_key = region.buffer_range.start.key;
4148            let buffer_start_value = region.buffer_range.start.value.unwrap();
4149            let mut buffer_key = buffer_start_key;
4150            buffer_key.add_assign(&(key - start_key));
4151            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4152            let mut result = start_value;
4153            result.add_assign(&(buffer_value - buffer_start_value));
4154            result
4155        } else {
4156            D2::from_text_summary(&self.text_summary())
4157        }
4158    }
4159
4160    pub fn point_to_buffer_offset<T: ToOffset>(
4161        &self,
4162        point: T,
4163    ) -> Option<(&BufferSnapshot, usize)> {
4164        let offset = point.to_offset(self);
4165        let mut cursor = self.cursor::<usize>();
4166        cursor.seek(&offset);
4167        let region = cursor.region()?;
4168        let overshoot = offset - region.range.start;
4169        let buffer_offset = region.buffer_range.start + overshoot;
4170        Some((region.buffer, buffer_offset))
4171    }
4172
4173    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4174        let mut cursor = self.cursor::<Point>();
4175        cursor.seek(&point);
4176        let region = cursor.region()?;
4177        let overshoot = point - region.range.start;
4178        let buffer_offset = region.buffer_range.start + overshoot;
4179        Some((region.buffer, buffer_offset, region.is_main_buffer))
4180    }
4181
4182    pub fn suggested_indents(
4183        &self,
4184        rows: impl IntoIterator<Item = u32>,
4185        cx: &App,
4186    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4187        let mut result = BTreeMap::new();
4188
4189        let mut rows_for_excerpt = Vec::new();
4190        let mut cursor = self.cursor::<Point>();
4191        let mut rows = rows.into_iter().peekable();
4192        let mut prev_row = u32::MAX;
4193        let mut prev_language_indent_size = IndentSize::default();
4194
4195        while let Some(row) = rows.next() {
4196            cursor.seek(&Point::new(row, 0));
4197            let Some(region) = cursor.region() else {
4198                continue;
4199            };
4200
4201            // Retrieve the language and indent size once for each disjoint region being indented.
4202            let single_indent_size = if row.saturating_sub(1) == prev_row {
4203                prev_language_indent_size
4204            } else {
4205                region
4206                    .buffer
4207                    .language_indent_size_at(Point::new(row, 0), cx)
4208            };
4209            prev_language_indent_size = single_indent_size;
4210            prev_row = row;
4211
4212            let start_buffer_row = region.buffer_range.start.row;
4213            let start_multibuffer_row = region.range.start.row;
4214            let end_multibuffer_row = region.range.end.row;
4215
4216            rows_for_excerpt.push(row);
4217            while let Some(next_row) = rows.peek().copied() {
4218                if end_multibuffer_row > next_row {
4219                    rows_for_excerpt.push(next_row);
4220                    rows.next();
4221                } else {
4222                    break;
4223                }
4224            }
4225
4226            let buffer_rows = rows_for_excerpt
4227                .drain(..)
4228                .map(|row| start_buffer_row + row - start_multibuffer_row);
4229            let buffer_indents = region
4230                .buffer
4231                .suggested_indents(buffer_rows, single_indent_size);
4232            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4233                (
4234                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4235                    indent,
4236                )
4237            });
4238            result.extend(multibuffer_indents);
4239        }
4240
4241        result
4242    }
4243
4244    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4245        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4246            let mut size = buffer.indent_size_for_line(range.start.row);
4247            size.len = size
4248                .len
4249                .min(range.end.column)
4250                .saturating_sub(range.start.column);
4251            size
4252        } else {
4253            IndentSize::spaces(0)
4254        }
4255    }
4256
4257    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4258        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4259            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4260        } else {
4261            LineIndent::spaces(0)
4262        }
4263    }
4264
4265    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4266        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4267
4268        if self.settings_at(0, cx).extend_comment_on_newline {
4269            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4270                let delimiters = language_scope.line_comment_prefixes();
4271                for delimiter in delimiters {
4272                    if *self
4273                        .chars_at(Point::new(row.0, indent.len() as u32))
4274                        .take(delimiter.chars().count())
4275                        .collect::<String>()
4276                        .as_str()
4277                        == **delimiter
4278                    {
4279                        indent.push_str(&delimiter);
4280                        break;
4281                    }
4282                }
4283            }
4284        }
4285
4286        indent
4287    }
4288
4289    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4290    where
4291        T: ToOffset,
4292    {
4293        for char in self.reversed_chars_at(position) {
4294            if !char.is_whitespace() {
4295                return false;
4296            }
4297            if char == '\n' {
4298                return true;
4299            }
4300        }
4301        return true;
4302    }
4303
4304    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4305        while row.0 > 0 {
4306            row.0 -= 1;
4307            if !self.is_line_blank(row) {
4308                return Some(row);
4309            }
4310        }
4311        None
4312    }
4313
4314    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4315        if let Some((_, range)) = self.buffer_line_for_row(row) {
4316            range.end.column - range.start.column
4317        } else {
4318            0
4319        }
4320    }
4321
4322    pub fn buffer_line_for_row(
4323        &self,
4324        row: MultiBufferRow,
4325    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4326        let mut cursor = self.cursor::<Point>();
4327        let point = Point::new(row.0, 0);
4328        cursor.seek(&point);
4329        let region = cursor.region()?;
4330        let overshoot = point.min(region.range.end) - region.range.start;
4331        let buffer_point = region.buffer_range.start + overshoot;
4332        if buffer_point.row > region.buffer_range.end.row {
4333            return None;
4334        }
4335        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4336        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4337            .min(region.buffer_range.end);
4338        Some((region.buffer, line_start..line_end))
4339    }
4340
4341    pub fn max_point(&self) -> Point {
4342        self.text_summary().lines
4343    }
4344
4345    pub fn max_row(&self) -> MultiBufferRow {
4346        MultiBufferRow(self.text_summary().lines.row)
4347    }
4348
4349    pub fn text_summary(&self) -> TextSummary {
4350        self.diff_transforms.summary().output
4351    }
4352
4353    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4354    where
4355        D: TextDimension,
4356        O: ToOffset,
4357    {
4358        let range = range.start.to_offset(self)..range.end.to_offset(self);
4359        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4360        cursor.seek(&range.start, Bias::Right, &());
4361
4362        let Some(first_transform) = cursor.item() else {
4363            return D::from_text_summary(&TextSummary::default());
4364        };
4365
4366        let diff_transform_start = cursor.start().0;
4367        let diff_transform_end = cursor.end(&()).0;
4368        let diff_start = range.start;
4369        let start_overshoot = diff_start - diff_transform_start;
4370        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4371
4372        let mut result = match first_transform {
4373            DiffTransform::BufferContent { .. } => {
4374                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4375                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4376                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4377            }
4378            DiffTransform::DeletedHunk {
4379                buffer_id,
4380                base_text_byte_range,
4381                has_trailing_newline,
4382                ..
4383            } => {
4384                let buffer_start = base_text_byte_range.start + start_overshoot;
4385                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4386                let Some(base_text) = self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4387                else {
4388                    panic!("{:?} is in non-existent deleted hunk", range.start)
4389                };
4390
4391                let include_trailing_newline =
4392                    *has_trailing_newline && range.end >= diff_transform_end;
4393                if include_trailing_newline {
4394                    buffer_end -= 1;
4395                }
4396
4397                let mut summary =
4398                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4399
4400                if include_trailing_newline {
4401                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4402                }
4403
4404                summary
4405            }
4406        };
4407        if range.end < diff_transform_end {
4408            return result;
4409        }
4410
4411        cursor.next(&());
4412        result.add_assign(&D::from_text_summary(&cursor.summary(
4413            &range.end,
4414            Bias::Right,
4415            &(),
4416        )));
4417
4418        let Some(last_transform) = cursor.item() else {
4419            return result;
4420        };
4421
4422        let overshoot = range.end - cursor.start().0;
4423        let suffix = match last_transform {
4424            DiffTransform::BufferContent { .. } => {
4425                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4426                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4427            }
4428            DiffTransform::DeletedHunk {
4429                base_text_byte_range,
4430                buffer_id,
4431                has_trailing_newline,
4432                ..
4433            } => {
4434                let buffer_end = base_text_byte_range.start + overshoot;
4435                let Some(base_text) = self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4436                else {
4437                    panic!("{:?} is in non-existent deleted hunk", range.end)
4438                };
4439
4440                let mut suffix = base_text
4441                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4442                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4443                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4444                }
4445                suffix
4446            }
4447        };
4448
4449        result.add_assign(&suffix);
4450        result
4451    }
4452
4453    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4454    where
4455        D: TextDimension,
4456    {
4457        // let mut range = range.start..range.end;
4458        let mut summary = D::zero(&());
4459        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4460        cursor.seek(&range.start, Bias::Right, &());
4461        if let Some(excerpt) = cursor.item() {
4462            let mut end_before_newline = cursor.end(&());
4463            if excerpt.has_trailing_newline {
4464                end_before_newline -= ExcerptOffset::new(1);
4465            }
4466
4467            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4468            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4469            let end_in_excerpt =
4470                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4471            summary.add_assign(
4472                &excerpt
4473                    .buffer
4474                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4475            );
4476
4477            if range.end > end_before_newline {
4478                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4479            }
4480
4481            cursor.next(&());
4482        }
4483
4484        if range.end > *cursor.start() {
4485            summary.add_assign(
4486                &cursor
4487                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4488                    .0,
4489            );
4490            if let Some(excerpt) = cursor.item() {
4491                range.end = cmp::max(*cursor.start(), range.end);
4492
4493                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4494                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4495                summary.add_assign(
4496                    &excerpt
4497                        .buffer
4498                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4499                );
4500            }
4501        }
4502
4503        summary
4504    }
4505
4506    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4507    where
4508        D: TextDimension + Ord + Sub<D, Output = D>,
4509    {
4510        self.summaries_for_anchors([anchor])[0]
4511    }
4512
4513    fn resolve_summary_for_anchor<D>(
4514        &self,
4515        anchor: &Anchor,
4516        excerpt_position: D,
4517        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4518    ) -> D
4519    where
4520        D: TextDimension + Ord + Sub<D, Output = D>,
4521    {
4522        loop {
4523            let transform_end_position = diff_transforms.end(&()).0 .0;
4524            let at_transform_end =
4525                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4526            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4527                diff_transforms.next(&());
4528                continue;
4529            }
4530
4531            let mut position = diff_transforms.start().1 .0;
4532            match diff_transforms.item() {
4533                Some(DiffTransform::DeletedHunk {
4534                    buffer_id,
4535                    base_text_byte_range,
4536                    ..
4537                }) => {
4538                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4539                        if let Some(base_text) =
4540                            self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4541                        {
4542                            if base_text.can_resolve(&diff_base_anchor) {
4543                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4544                                if base_text_offset >= base_text_byte_range.start
4545                                    && base_text_offset <= base_text_byte_range.end
4546                                {
4547                                    let position_in_hunk = base_text
4548                                        .text_summary_for_range::<D, _>(
4549                                            base_text_byte_range.start..base_text_offset,
4550                                        );
4551                                    position.add_assign(&position_in_hunk);
4552                                } else if at_transform_end {
4553                                    diff_transforms.next(&());
4554                                    continue;
4555                                }
4556                            }
4557                        }
4558                    }
4559                }
4560                _ => {
4561                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4562                        diff_transforms.next(&());
4563                        continue;
4564                    }
4565                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4566                    position.add_assign(&overshoot);
4567                }
4568            }
4569
4570            return position;
4571        }
4572    }
4573
4574    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4575        let mut cursor = self
4576            .excerpts
4577            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4578        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4579
4580        cursor.seek(&Some(locator), Bias::Left, &());
4581        if cursor.item().is_none() {
4582            cursor.next(&());
4583        }
4584
4585        let mut position = cursor.start().1;
4586        if let Some(excerpt) = cursor.item() {
4587            if excerpt.id == anchor.excerpt_id {
4588                let excerpt_buffer_start = excerpt
4589                    .buffer
4590                    .offset_for_anchor(&excerpt.range.context.start);
4591                let excerpt_buffer_end =
4592                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4593                let buffer_position = cmp::min(
4594                    excerpt_buffer_end,
4595                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4596                );
4597                if buffer_position > excerpt_buffer_start {
4598                    position.value += buffer_position - excerpt_buffer_start;
4599                }
4600            }
4601        }
4602        position
4603    }
4604
4605    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4606    where
4607        D: TextDimension + Ord + Sub<D, Output = D>,
4608        I: 'a + IntoIterator<Item = &'a Anchor>,
4609    {
4610        let mut anchors = anchors.into_iter().peekable();
4611        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4612        let mut diff_transforms_cursor = self
4613            .diff_transforms
4614            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4615        diff_transforms_cursor.next(&());
4616
4617        let mut summaries = Vec::new();
4618        while let Some(anchor) = anchors.peek() {
4619            let excerpt_id = anchor.excerpt_id;
4620            let excerpt_anchors = iter::from_fn(|| {
4621                let anchor = anchors.peek()?;
4622                if anchor.excerpt_id == excerpt_id {
4623                    Some(anchors.next().unwrap())
4624                } else {
4625                    None
4626                }
4627            });
4628
4629            let locator = self.excerpt_locator_for_id(excerpt_id);
4630            cursor.seek_forward(locator, Bias::Left, &());
4631            if cursor.item().is_none() {
4632                cursor.next(&());
4633            }
4634
4635            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4636            if let Some(excerpt) = cursor.item() {
4637                if excerpt.id != excerpt_id {
4638                    let position = self.resolve_summary_for_anchor(
4639                        &Anchor::min(),
4640                        excerpt_start_position,
4641                        &mut diff_transforms_cursor,
4642                    );
4643                    summaries.extend(excerpt_anchors.map(|_| position));
4644                    continue;
4645                }
4646                let excerpt_buffer_start =
4647                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4648                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4649                for (buffer_summary, anchor) in excerpt
4650                    .buffer
4651                    .summaries_for_anchors_with_payload::<D, _, _>(
4652                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4653                    )
4654                {
4655                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4656                    let mut position = excerpt_start_position;
4657                    if summary > excerpt_buffer_start {
4658                        position.add_assign(&(summary - excerpt_buffer_start));
4659                    }
4660
4661                    if position > diff_transforms_cursor.start().0 .0 {
4662                        diff_transforms_cursor.seek_forward(
4663                            &ExcerptDimension(position),
4664                            Bias::Left,
4665                            &(),
4666                        );
4667                    }
4668
4669                    summaries.push(self.resolve_summary_for_anchor(
4670                        anchor,
4671                        position,
4672                        &mut diff_transforms_cursor,
4673                    ));
4674                }
4675            } else {
4676                diff_transforms_cursor.seek_forward(
4677                    &ExcerptDimension(excerpt_start_position),
4678                    Bias::Left,
4679                    &(),
4680                );
4681                let position = self.resolve_summary_for_anchor(
4682                    &Anchor::max(),
4683                    excerpt_start_position,
4684                    &mut diff_transforms_cursor,
4685                );
4686                summaries.extend(excerpt_anchors.map(|_| position));
4687            }
4688        }
4689
4690        summaries
4691    }
4692
4693    pub fn dimensions_from_points<'a, D>(
4694        &'a self,
4695        points: impl 'a + IntoIterator<Item = Point>,
4696    ) -> impl 'a + Iterator<Item = D>
4697    where
4698        D: TextDimension + Sub<D, Output = D>,
4699    {
4700        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4701        cursor.seek(&DimensionPair {
4702            key: Point::default(),
4703            value: None,
4704        });
4705        let mut points = points.into_iter();
4706        iter::from_fn(move || {
4707            let point = points.next()?;
4708
4709            cursor.seek_forward(&DimensionPair {
4710                key: point,
4711                value: None,
4712            });
4713
4714            if let Some(region) = cursor.region() {
4715                let overshoot = point - region.range.start.key;
4716                let buffer_point = region.buffer_range.start.key + overshoot;
4717                let mut position = region.range.start.value.unwrap();
4718                position.add_assign(
4719                    &region
4720                        .buffer
4721                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4722                );
4723                return Some(position);
4724            } else {
4725                return Some(D::from_text_summary(&self.text_summary()));
4726            }
4727        })
4728    }
4729
4730    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4731    where
4732        I: 'a + IntoIterator<Item = &'a Anchor>,
4733    {
4734        let mut anchors = anchors.into_iter().enumerate().peekable();
4735        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4736        cursor.next(&());
4737
4738        let mut result = Vec::new();
4739
4740        while let Some((_, anchor)) = anchors.peek() {
4741            let old_excerpt_id = anchor.excerpt_id;
4742
4743            // Find the location where this anchor's excerpt should be.
4744            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4745            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4746
4747            if cursor.item().is_none() {
4748                cursor.next(&());
4749            }
4750
4751            let next_excerpt = cursor.item();
4752            let prev_excerpt = cursor.prev_item();
4753
4754            // Process all of the anchors for this excerpt.
4755            while let Some((_, anchor)) = anchors.peek() {
4756                if anchor.excerpt_id != old_excerpt_id {
4757                    break;
4758                }
4759                let (anchor_ix, anchor) = anchors.next().unwrap();
4760                let mut anchor = *anchor;
4761
4762                // Leave min and max anchors unchanged if invalid or
4763                // if the old excerpt still exists at this location
4764                let mut kept_position = next_excerpt
4765                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4766                    || old_excerpt_id == ExcerptId::max()
4767                    || old_excerpt_id == ExcerptId::min();
4768
4769                // If the old excerpt no longer exists at this location, then attempt to
4770                // find an equivalent position for this anchor in an adjacent excerpt.
4771                if !kept_position {
4772                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4773                        if excerpt.contains(&anchor) {
4774                            anchor.excerpt_id = excerpt.id;
4775                            kept_position = true;
4776                            break;
4777                        }
4778                    }
4779                }
4780
4781                // If there's no adjacent excerpt that contains the anchor's position,
4782                // then report that the anchor has lost its position.
4783                if !kept_position {
4784                    anchor = if let Some(excerpt) = next_excerpt {
4785                        let mut text_anchor = excerpt
4786                            .range
4787                            .context
4788                            .start
4789                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4790                        if text_anchor
4791                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4792                            .is_gt()
4793                        {
4794                            text_anchor = excerpt.range.context.end;
4795                        }
4796                        Anchor {
4797                            buffer_id: Some(excerpt.buffer_id),
4798                            excerpt_id: excerpt.id,
4799                            text_anchor,
4800                            diff_base_anchor: None,
4801                        }
4802                    } else if let Some(excerpt) = prev_excerpt {
4803                        let mut text_anchor = excerpt
4804                            .range
4805                            .context
4806                            .end
4807                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4808                        if text_anchor
4809                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4810                            .is_lt()
4811                        {
4812                            text_anchor = excerpt.range.context.start;
4813                        }
4814                        Anchor {
4815                            buffer_id: Some(excerpt.buffer_id),
4816                            excerpt_id: excerpt.id,
4817                            text_anchor,
4818                            diff_base_anchor: None,
4819                        }
4820                    } else if anchor.text_anchor.bias == Bias::Left {
4821                        Anchor::min()
4822                    } else {
4823                        Anchor::max()
4824                    };
4825                }
4826
4827                result.push((anchor_ix, anchor, kept_position));
4828            }
4829        }
4830        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4831        result
4832    }
4833
4834    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4835        self.anchor_at(position, Bias::Left)
4836    }
4837
4838    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4839        self.anchor_at(position, Bias::Right)
4840    }
4841
4842    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4843        let offset = position.to_offset(self);
4844
4845        // Find the given position in the diff transforms. Determine the corresponding
4846        // offset in the excerpts, and whether the position is within a deleted hunk.
4847        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4848        diff_transforms.seek(&offset, Bias::Right, &());
4849
4850        if offset == diff_transforms.start().0 && bias == Bias::Left {
4851            if let Some(prev_item) = diff_transforms.prev_item() {
4852                match prev_item {
4853                    DiffTransform::DeletedHunk { .. } => {
4854                        diff_transforms.prev(&());
4855                    }
4856                    _ => {}
4857                }
4858            }
4859        }
4860        let offset_in_transform = offset - diff_transforms.start().0;
4861        let mut excerpt_offset = diff_transforms.start().1;
4862        let mut diff_base_anchor = None;
4863        if let Some(DiffTransform::DeletedHunk {
4864            buffer_id,
4865            base_text_byte_range,
4866            has_trailing_newline,
4867            ..
4868        }) = diff_transforms.item()
4869        {
4870            let base_text = self
4871                .diffs
4872                .get(buffer_id)
4873                .and_then(|diff| diff.base_text())
4874                .expect("missing diff base");
4875            if offset_in_transform > base_text_byte_range.len() {
4876                debug_assert!(*has_trailing_newline);
4877                bias = Bias::Right;
4878            } else {
4879                diff_base_anchor = Some(
4880                    base_text.anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4881                );
4882                bias = Bias::Left;
4883            }
4884        } else {
4885            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4886        };
4887
4888        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4889            return Anchor {
4890                buffer_id: Some(buffer_id),
4891                excerpt_id: *excerpt_id,
4892                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4893                diff_base_anchor,
4894            };
4895        }
4896
4897        let mut excerpts = self
4898            .excerpts
4899            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4900        excerpts.seek(&excerpt_offset, Bias::Right, &());
4901        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4902            excerpts.prev(&());
4903        }
4904        if let Some(excerpt) = excerpts.item() {
4905            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4906            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4907                overshoot -= 1;
4908                bias = Bias::Right;
4909            }
4910
4911            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4912            let text_anchor =
4913                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4914            Anchor {
4915                buffer_id: Some(excerpt.buffer_id),
4916                excerpt_id: excerpt.id,
4917                text_anchor,
4918                diff_base_anchor,
4919            }
4920        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4921            Anchor::min()
4922        } else {
4923            Anchor::max()
4924        }
4925    }
4926
4927    /// Returns an anchor for the given excerpt and text anchor,
4928    /// returns None if the excerpt_id is no longer valid.
4929    pub fn anchor_in_excerpt(
4930        &self,
4931        excerpt_id: ExcerptId,
4932        text_anchor: text::Anchor,
4933    ) -> Option<Anchor> {
4934        let locator = self.excerpt_locator_for_id(excerpt_id);
4935        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4936        cursor.seek(locator, Bias::Left, &());
4937        if let Some(excerpt) = cursor.item() {
4938            if excerpt.id == excerpt_id {
4939                let text_anchor = excerpt.clip_anchor(text_anchor);
4940                drop(cursor);
4941                return Some(Anchor {
4942                    buffer_id: Some(excerpt.buffer_id),
4943                    excerpt_id,
4944                    text_anchor,
4945                    diff_base_anchor: None,
4946                });
4947            }
4948        }
4949        None
4950    }
4951
4952    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4953        Some(self.excerpt(excerpt_id)?.range.context.clone())
4954    }
4955
4956    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4957        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4958            true
4959        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4960            excerpt.buffer.can_resolve(&anchor.text_anchor)
4961        } else {
4962            false
4963        }
4964    }
4965
4966    pub fn excerpts(
4967        &self,
4968    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4969        self.excerpts
4970            .iter()
4971            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4972    }
4973
4974    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4975        let excerpts = self.excerpts.cursor(&());
4976        let diff_transforms = self.diff_transforms.cursor(&());
4977        MultiBufferCursor {
4978            excerpts,
4979            diff_transforms,
4980            diffs: &self.diffs,
4981            cached_region: None,
4982        }
4983    }
4984
4985    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4986        let start_locator = self.excerpt_locator_for_id(id);
4987        let mut excerpts = self
4988            .excerpts
4989            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4990        excerpts.seek(&Some(start_locator), Bias::Left, &());
4991        excerpts.prev(&());
4992
4993        let mut diff_transforms = self
4994            .diff_transforms
4995            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4996        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4997        if diff_transforms.end(&()).1 < excerpts.start().1 {
4998            diff_transforms.next(&());
4999        }
5000
5001        let excerpt = excerpts.item()?;
5002        Some(MultiBufferExcerpt {
5003            excerpt,
5004            offset: diff_transforms.start().0 .0,
5005            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5006            excerpt_offset: excerpts.start().1.clone(),
5007            diff_transforms,
5008        })
5009    }
5010
5011    pub fn excerpt_boundaries_in_range<R, T>(
5012        &self,
5013        range: R,
5014    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5015    where
5016        R: RangeBounds<T>,
5017        T: ToOffset,
5018    {
5019        let start_offset;
5020        let start = match range.start_bound() {
5021            Bound::Included(start) => {
5022                start_offset = start.to_offset(self);
5023                Bound::Included(start_offset)
5024            }
5025            Bound::Excluded(_) => {
5026                panic!("not supported")
5027            }
5028            Bound::Unbounded => {
5029                start_offset = 0;
5030                Bound::Unbounded
5031            }
5032        };
5033        let end = match range.end_bound() {
5034            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5035            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5036            Bound::Unbounded => Bound::Unbounded,
5037        };
5038        let bounds = (start, end);
5039
5040        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5041        cursor.seek(&DimensionPair {
5042            key: start_offset,
5043            value: None,
5044        });
5045
5046        if cursor
5047            .region()
5048            .is_some_and(|region| bounds.contains(&region.range.start.key))
5049        {
5050            cursor.prev_excerpt();
5051        } else {
5052            cursor.seek_to_start_of_current_excerpt();
5053        }
5054        let mut prev_region = cursor.region();
5055
5056        cursor.next_excerpt();
5057
5058        let mut visited_end = false;
5059        iter::from_fn(move || loop {
5060            if self.singleton {
5061                return None;
5062            }
5063
5064            let next_region = cursor.region();
5065            cursor.next_excerpt();
5066
5067            let next_region_start = if let Some(region) = &next_region {
5068                if !bounds.contains(&region.range.start.key) {
5069                    prev_region = next_region;
5070                    continue;
5071                }
5072                region.range.start.value.unwrap()
5073            } else {
5074                if !bounds.contains(&self.len()) {
5075                    return None;
5076                }
5077                self.max_point()
5078            };
5079            let next_region_end = if let Some(region) = cursor.region() {
5080                region.range.start.value.unwrap()
5081            } else {
5082                self.max_point()
5083            };
5084
5085            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5086                id: region.excerpt.id,
5087                buffer: region.excerpt.buffer.clone(),
5088                buffer_id: region.excerpt.buffer_id,
5089                range: region.excerpt.range.clone(),
5090                end_row: MultiBufferRow(next_region_start.row),
5091            });
5092
5093            let next = next_region.as_ref().map(|region| ExcerptInfo {
5094                id: region.excerpt.id,
5095                buffer: region.excerpt.buffer.clone(),
5096                buffer_id: region.excerpt.buffer_id,
5097                range: region.excerpt.range.clone(),
5098                end_row: if region.excerpt.has_trailing_newline {
5099                    MultiBufferRow(next_region_end.row - 1)
5100                } else {
5101                    MultiBufferRow(next_region_end.row)
5102                },
5103            });
5104
5105            if next.is_none() {
5106                if visited_end {
5107                    return None;
5108                } else {
5109                    visited_end = true;
5110                }
5111            }
5112
5113            let row = MultiBufferRow(next_region_start.row);
5114
5115            prev_region = next_region;
5116
5117            return Some(ExcerptBoundary { row, prev, next });
5118        })
5119    }
5120
5121    pub fn edit_count(&self) -> usize {
5122        self.edit_count
5123    }
5124
5125    pub fn non_text_state_update_count(&self) -> usize {
5126        self.non_text_state_update_count
5127    }
5128
5129    /// Returns the smallest enclosing bracket ranges containing the given range or
5130    /// None if no brackets contain range or the range is not contained in a single
5131    /// excerpt
5132    ///
5133    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5134    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5135        &self,
5136        range: Range<T>,
5137        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5138    ) -> Option<(Range<usize>, Range<usize>)> {
5139        let range = range.start.to_offset(self)..range.end.to_offset(self);
5140        let mut excerpt = self.excerpt_containing(range.clone())?;
5141        let buffer = excerpt.buffer();
5142        let excerpt_buffer_range = excerpt.buffer_range();
5143
5144        // Filter to ranges contained in the excerpt
5145        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5146            excerpt_buffer_range.contains(&open.start)
5147                && excerpt_buffer_range.contains(&close.end)
5148                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5149        };
5150
5151        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5152            excerpt.map_range_to_buffer(range),
5153            Some(&range_filter),
5154        )?;
5155
5156        Some((
5157            excerpt.map_range_from_buffer(open),
5158            excerpt.map_range_from_buffer(close),
5159        ))
5160    }
5161
5162    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5163    /// not contained in a single excerpt
5164    pub fn enclosing_bracket_ranges<T: ToOffset>(
5165        &self,
5166        range: Range<T>,
5167    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5168        let range = range.start.to_offset(self)..range.end.to_offset(self);
5169        let mut excerpt = self.excerpt_containing(range.clone())?;
5170
5171        Some(
5172            excerpt
5173                .buffer()
5174                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5175                .filter_map(move |pair| {
5176                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5177                        Some((
5178                            excerpt.map_range_from_buffer(pair.open_range),
5179                            excerpt.map_range_from_buffer(pair.close_range),
5180                        ))
5181                    } else {
5182                        None
5183                    }
5184                }),
5185        )
5186    }
5187
5188    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5189    /// not contained in a single excerpt
5190    pub fn text_object_ranges<T: ToOffset>(
5191        &self,
5192        range: Range<T>,
5193        options: TreeSitterOptions,
5194    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5195        let range = range.start.to_offset(self)..range.end.to_offset(self);
5196        self.excerpt_containing(range.clone())
5197            .map(|mut excerpt| {
5198                excerpt
5199                    .buffer()
5200                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5201                    .filter_map(move |(range, text_object)| {
5202                        if excerpt.contains_buffer_range(range.clone()) {
5203                            Some((excerpt.map_range_from_buffer(range), text_object))
5204                        } else {
5205                            None
5206                        }
5207                    })
5208            })
5209            .into_iter()
5210            .flatten()
5211    }
5212
5213    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5214    /// not contained in a single excerpt
5215    pub fn bracket_ranges<T: ToOffset>(
5216        &self,
5217        range: Range<T>,
5218    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5219        let range = range.start.to_offset(self)..range.end.to_offset(self);
5220        let mut excerpt = self.excerpt_containing(range.clone())?;
5221
5222        Some(
5223            excerpt
5224                .buffer()
5225                .bracket_ranges(excerpt.map_range_to_buffer(range))
5226                .filter_map(move |pair| {
5227                    let buffer_range = pair.open_range.start..pair.close_range.end;
5228                    if excerpt.contains_buffer_range(buffer_range) {
5229                        Some((
5230                            excerpt.map_range_from_buffer(pair.open_range),
5231                            excerpt.map_range_from_buffer(pair.close_range),
5232                        ))
5233                    } else {
5234                        None
5235                    }
5236                }),
5237        )
5238    }
5239
5240    pub fn redacted_ranges<'a, T: ToOffset>(
5241        &'a self,
5242        range: Range<T>,
5243        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5244    ) -> impl Iterator<Item = Range<usize>> + 'a {
5245        let range = range.start.to_offset(self)..range.end.to_offset(self);
5246        self.lift_buffer_metadata(range, move |buffer, range| {
5247            if redaction_enabled(buffer.file()) {
5248                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5249            } else {
5250                None
5251            }
5252        })
5253        .map(|(range, _, _)| range)
5254    }
5255
5256    pub fn runnable_ranges(
5257        &self,
5258        range: Range<Anchor>,
5259    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5260        let range = range.start.to_offset(self)..range.end.to_offset(self);
5261        self.lift_buffer_metadata(range, move |buffer, range| {
5262            Some(
5263                buffer
5264                    .runnable_ranges(range.clone())
5265                    .filter(move |runnable| {
5266                        runnable.run_range.start >= range.start
5267                            && runnable.run_range.end < range.end
5268                    })
5269                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5270            )
5271        })
5272        .map(|(run_range, runnable, _)| language::RunnableRange {
5273            run_range,
5274            ..runnable
5275        })
5276    }
5277
5278    pub fn line_indents(
5279        &self,
5280        start_row: MultiBufferRow,
5281        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5282    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5283        let max_point = self.max_point();
5284        let mut cursor = self.cursor::<Point>();
5285        cursor.seek(&Point::new(start_row.0, 0));
5286        iter::from_fn(move || {
5287            let mut region = cursor.region()?;
5288            while !buffer_filter(&region.excerpt.buffer) {
5289                cursor.next();
5290                region = cursor.region()?;
5291            }
5292            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5293            let buffer_start_row =
5294                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5295
5296            let buffer_end_row = if region.is_main_buffer
5297                && (region.has_trailing_newline || region.range.end == max_point)
5298            {
5299                region.buffer_range.end.row
5300            } else {
5301                region.buffer_range.end.row.saturating_sub(1)
5302            };
5303
5304            let line_indents = region
5305                .buffer
5306                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5307            cursor.next();
5308            return Some(line_indents.map(move |(buffer_row, indent)| {
5309                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5310                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5311            }));
5312        })
5313        .flatten()
5314    }
5315
5316    pub fn reversed_line_indents(
5317        &self,
5318        end_row: MultiBufferRow,
5319        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5320    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5321        let max_point = self.max_point();
5322        let mut cursor = self.cursor::<Point>();
5323        cursor.seek(&Point::new(end_row.0, 0));
5324        iter::from_fn(move || {
5325            let mut region = cursor.region()?;
5326            while !buffer_filter(&region.excerpt.buffer) {
5327                cursor.prev();
5328                region = cursor.region()?;
5329            }
5330
5331            let buffer_start_row = region.buffer_range.start.row;
5332            let buffer_end_row = if region.is_main_buffer
5333                && (region.has_trailing_newline || region.range.end == max_point)
5334            {
5335                region.buffer_range.end.row + 1
5336            } else {
5337                region.buffer_range.end.row
5338            };
5339
5340            let overshoot = end_row.0 - region.range.start.row;
5341            let buffer_end_row =
5342                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5343
5344            let line_indents = region
5345                .buffer
5346                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5347            cursor.prev();
5348            return Some(line_indents.map(move |(buffer_row, indent)| {
5349                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5350                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5351            }));
5352        })
5353        .flatten()
5354    }
5355
5356    pub async fn enclosing_indent(
5357        &self,
5358        mut target_row: MultiBufferRow,
5359    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5360        let max_row = MultiBufferRow(self.max_point().row);
5361        if target_row >= max_row {
5362            return None;
5363        }
5364
5365        let mut target_indent = self.line_indent_for_row(target_row);
5366
5367        // If the current row is at the start of an indented block, we want to return this
5368        // block as the enclosing indent.
5369        if !target_indent.is_line_empty() && target_row < max_row {
5370            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5371            if !next_line_indent.is_line_empty()
5372                && target_indent.raw_len() < next_line_indent.raw_len()
5373            {
5374                target_indent = next_line_indent;
5375                target_row.0 += 1;
5376            }
5377        }
5378
5379        const SEARCH_ROW_LIMIT: u32 = 25000;
5380        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5381        const YIELD_INTERVAL: u32 = 100;
5382
5383        let mut accessed_row_counter = 0;
5384
5385        // If there is a blank line at the current row, search for the next non indented lines
5386        if target_indent.is_line_empty() {
5387            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5388            let end =
5389                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5390
5391            let mut non_empty_line_above = None;
5392            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5393                if row < start {
5394                    break;
5395                }
5396                accessed_row_counter += 1;
5397                if accessed_row_counter == YIELD_INTERVAL {
5398                    accessed_row_counter = 0;
5399                    yield_now().await;
5400                }
5401                if !indent.is_line_empty() {
5402                    non_empty_line_above = Some((row, indent));
5403                    break;
5404                }
5405            }
5406
5407            let mut non_empty_line_below = None;
5408            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5409                if row > end {
5410                    break;
5411                }
5412                accessed_row_counter += 1;
5413                if accessed_row_counter == YIELD_INTERVAL {
5414                    accessed_row_counter = 0;
5415                    yield_now().await;
5416                }
5417                if !indent.is_line_empty() {
5418                    non_empty_line_below = Some((row, indent));
5419                    break;
5420                }
5421            }
5422
5423            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5424                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5425                    if above_indent.raw_len() >= below_indent.raw_len() {
5426                        (above_row, above_indent)
5427                    } else {
5428                        (below_row, below_indent)
5429                    }
5430                }
5431                (Some(above), None) => above,
5432                (None, Some(below)) => below,
5433                _ => return None,
5434            };
5435
5436            target_indent = indent;
5437            target_row = row;
5438        }
5439
5440        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5441        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5442
5443        let mut start_indent = None;
5444        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5445            if row < start {
5446                break;
5447            }
5448            accessed_row_counter += 1;
5449            if accessed_row_counter == YIELD_INTERVAL {
5450                accessed_row_counter = 0;
5451                yield_now().await;
5452            }
5453            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5454                start_indent = Some((row, indent));
5455                break;
5456            }
5457        }
5458        let (start_row, start_indent_size) = start_indent?;
5459
5460        let mut end_indent = (end, None);
5461        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5462            if row > end {
5463                break;
5464            }
5465            accessed_row_counter += 1;
5466            if accessed_row_counter == YIELD_INTERVAL {
5467                accessed_row_counter = 0;
5468                yield_now().await;
5469            }
5470            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5471                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5472                break;
5473            }
5474        }
5475        let (end_row, end_indent_size) = end_indent;
5476
5477        let indent = if let Some(end_indent_size) = end_indent_size {
5478            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5479                start_indent_size
5480            } else {
5481                end_indent_size
5482            }
5483        } else {
5484            start_indent_size
5485        };
5486
5487        Some((start_row..end_row, indent))
5488    }
5489
5490    pub fn indent_guides_in_range<T: ToPoint>(
5491        &self,
5492        range: Range<T>,
5493        ignore_disabled_for_language: bool,
5494        cx: &App,
5495    ) -> impl Iterator<Item = IndentGuide> {
5496        let range = range.start.to_point(self)..range.end.to_point(self);
5497        let start_row = MultiBufferRow(range.start.row);
5498        let end_row = MultiBufferRow(range.end.row);
5499
5500        let mut row_indents = self.line_indents(start_row, |buffer| {
5501            let settings =
5502                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5503            settings.indent_guides.enabled || ignore_disabled_for_language
5504        });
5505
5506        let mut result = Vec::new();
5507        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5508
5509        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5510            if first_row > end_row {
5511                break;
5512            }
5513            let current_depth = indent_stack.len() as u32;
5514
5515            let settings =
5516                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5517            let tab_size = settings.tab_size.get() as u32;
5518
5519            // When encountering empty, continue until found useful line indent
5520            // then add to the indent stack with the depth found
5521            let mut found_indent = false;
5522            let mut last_row = first_row;
5523            if line_indent.is_line_empty() {
5524                while !found_indent {
5525                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5526                        break;
5527                    };
5528                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5529                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5530                        break;
5531                    }
5532
5533                    if new_line_indent.is_line_empty() {
5534                        continue;
5535                    }
5536                    last_row = target_row.min(end_row);
5537                    line_indent = new_line_indent;
5538                    found_indent = true;
5539                    break;
5540                }
5541            } else {
5542                found_indent = true
5543            }
5544
5545            let depth = if found_indent {
5546                line_indent.len(tab_size) / tab_size
5547                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5548            } else {
5549                current_depth
5550            };
5551
5552            match depth.cmp(&current_depth) {
5553                cmp::Ordering::Less => {
5554                    for _ in 0..(current_depth - depth) {
5555                        let mut indent = indent_stack.pop().unwrap();
5556                        if last_row != first_row {
5557                            // In this case, we landed on an empty row, had to seek forward,
5558                            // and discovered that the indent we where on is ending.
5559                            // This means that the last display row must
5560                            // be on line that ends this indent range, so we
5561                            // should display the range up to the first non-empty line
5562                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5563                        }
5564
5565                        result.push(indent)
5566                    }
5567                }
5568                cmp::Ordering::Greater => {
5569                    for next_depth in current_depth..depth {
5570                        indent_stack.push(IndentGuide {
5571                            buffer_id: buffer.remote_id(),
5572                            start_row: first_row,
5573                            end_row: last_row,
5574                            depth: next_depth,
5575                            tab_size,
5576                            settings: settings.indent_guides,
5577                        });
5578                    }
5579                }
5580                _ => {}
5581            }
5582
5583            for indent in indent_stack.iter_mut() {
5584                indent.end_row = last_row;
5585            }
5586        }
5587
5588        result.extend(indent_stack);
5589        result.into_iter()
5590    }
5591
5592    pub fn trailing_excerpt_update_count(&self) -> usize {
5593        self.trailing_excerpt_update_count
5594    }
5595
5596    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5597        self.point_to_buffer_offset(point)
5598            .and_then(|(buffer, _)| buffer.file())
5599    }
5600
5601    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5602        self.point_to_buffer_offset(point)
5603            .and_then(|(buffer, offset)| buffer.language_at(offset))
5604    }
5605
5606    pub fn settings_at<'a, T: ToOffset>(
5607        &'a self,
5608        point: T,
5609        cx: &'a App,
5610    ) -> Cow<'a, LanguageSettings> {
5611        let mut language = None;
5612        let mut file = None;
5613        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5614            language = buffer.language_at(offset);
5615            file = buffer.file();
5616        }
5617        language_settings(language.map(|l| l.name()), file, cx)
5618    }
5619
5620    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5621        self.point_to_buffer_offset(point)
5622            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5623    }
5624
5625    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5626        self.point_to_buffer_offset(point)
5627            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5628            .unwrap_or_default()
5629    }
5630
5631    pub fn language_indent_size_at<T: ToOffset>(
5632        &self,
5633        position: T,
5634        cx: &App,
5635    ) -> Option<IndentSize> {
5636        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5637        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5638    }
5639
5640    pub fn is_dirty(&self) -> bool {
5641        self.is_dirty
5642    }
5643
5644    pub fn has_deleted_file(&self) -> bool {
5645        self.has_deleted_file
5646    }
5647
5648    pub fn has_conflict(&self) -> bool {
5649        self.has_conflict
5650    }
5651
5652    pub fn has_diagnostics(&self) -> bool {
5653        self.excerpts
5654            .iter()
5655            .any(|excerpt| excerpt.buffer.has_diagnostics())
5656    }
5657
5658    pub fn diagnostic_group(
5659        &self,
5660        buffer_id: BufferId,
5661        group_id: usize,
5662    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5663        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5664            if buffer.remote_id() != buffer_id {
5665                return None;
5666            };
5667            Some(
5668                buffer
5669                    .diagnostic_group(group_id)
5670                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5671            )
5672        })
5673        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5674    }
5675
5676    pub fn diagnostics_in_range<'a, T>(
5677        &'a self,
5678        range: Range<T>,
5679    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5680    where
5681        T: 'a
5682            + text::ToOffset
5683            + text::FromAnchor
5684            + TextDimension
5685            + Ord
5686            + Sub<T, Output = T>
5687            + fmt::Debug,
5688    {
5689        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5690            Some(
5691                buffer
5692                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5693                    .map(|entry| (entry.range, entry.diagnostic)),
5694            )
5695        })
5696        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5697    }
5698
5699    pub fn syntax_ancestor<T: ToOffset>(
5700        &self,
5701        range: Range<T>,
5702    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5703        let range = range.start.to_offset(self)..range.end.to_offset(self);
5704        let mut excerpt = self.excerpt_containing(range.clone())?;
5705        let node = excerpt
5706            .buffer()
5707            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5708        let node_range = node.byte_range();
5709        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5710            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5711        } else {
5712            MultiOrSingleBufferOffsetRange::Single(node_range)
5713        };
5714        Some((node, range))
5715    }
5716
5717    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5718        let (excerpt_id, _, buffer) = self.as_singleton()?;
5719        let outline = buffer.outline(theme)?;
5720        Some(Outline::new(
5721            outline
5722                .items
5723                .into_iter()
5724                .flat_map(|item| {
5725                    Some(OutlineItem {
5726                        depth: item.depth,
5727                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5728                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5729                        text: item.text,
5730                        highlight_ranges: item.highlight_ranges,
5731                        name_ranges: item.name_ranges,
5732                        body_range: item.body_range.and_then(|body_range| {
5733                            Some(
5734                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5735                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5736                            )
5737                        }),
5738                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5739                            Some(
5740                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5741                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5742                            )
5743                        }),
5744                    })
5745                })
5746                .collect(),
5747        ))
5748    }
5749
5750    pub fn symbols_containing<T: ToOffset>(
5751        &self,
5752        offset: T,
5753        theme: Option<&SyntaxTheme>,
5754    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5755        let anchor = self.anchor_before(offset);
5756        let excerpt_id = anchor.excerpt_id;
5757        let excerpt = self.excerpt(excerpt_id)?;
5758        Some((
5759            excerpt.buffer_id,
5760            excerpt
5761                .buffer
5762                .symbols_containing(anchor.text_anchor, theme)
5763                .into_iter()
5764                .flatten()
5765                .flat_map(|item| {
5766                    Some(OutlineItem {
5767                        depth: item.depth,
5768                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5769                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5770                        text: item.text,
5771                        highlight_ranges: item.highlight_ranges,
5772                        name_ranges: item.name_ranges,
5773                        body_range: item.body_range.and_then(|body_range| {
5774                            Some(
5775                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5776                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5777                            )
5778                        }),
5779                        annotation_range: item.annotation_range.and_then(|body_range| {
5780                            Some(
5781                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5782                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5783                            )
5784                        }),
5785                    })
5786                })
5787                .collect(),
5788        ))
5789    }
5790
5791    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5792        if id == ExcerptId::min() {
5793            Locator::min_ref()
5794        } else if id == ExcerptId::max() {
5795            Locator::max_ref()
5796        } else {
5797            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5798            cursor.seek(&id, Bias::Left, &());
5799            if let Some(entry) = cursor.item() {
5800                if entry.id == id {
5801                    return &entry.locator;
5802                }
5803            }
5804            panic!("invalid excerpt id {:?}", id)
5805        }
5806    }
5807
5808    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5809    fn excerpt_locators_for_ids(
5810        &self,
5811        ids: impl IntoIterator<Item = ExcerptId>,
5812    ) -> SmallVec<[Locator; 1]> {
5813        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5814        sorted_ids.sort_unstable();
5815        let mut locators = SmallVec::new();
5816
5817        while sorted_ids.last() == Some(&ExcerptId::max()) {
5818            sorted_ids.pop();
5819            if let Some(mapping) = self.excerpt_ids.last() {
5820                locators.push(mapping.locator.clone());
5821            }
5822        }
5823
5824        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5825        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5826            sorted_ids.next();
5827            if let Some(mapping) = self.excerpt_ids.first() {
5828                locators.push(mapping.locator.clone());
5829            }
5830        }
5831
5832        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5833        for id in sorted_ids {
5834            if cursor.seek_forward(&id, Bias::Left, &()) {
5835                locators.push(cursor.item().unwrap().locator.clone());
5836            } else {
5837                panic!("invalid excerpt id {:?}", id);
5838            }
5839        }
5840
5841        locators.sort_unstable();
5842        locators
5843    }
5844
5845    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5846        Some(self.excerpt(excerpt_id)?.buffer_id)
5847    }
5848
5849    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5850        Some(&self.excerpt(excerpt_id)?.buffer)
5851    }
5852
5853    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5854        let mut cursor = self
5855            .excerpts
5856            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5857        let locator = self.excerpt_locator_for_id(excerpt_id);
5858        if cursor.seek(&Some(locator), Bias::Left, &()) {
5859            let start = cursor.start().1.clone();
5860            let end = cursor.end(&()).1;
5861            let mut diff_transforms = self
5862                .diff_transforms
5863                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5864            diff_transforms.seek(&start, Bias::Left, &());
5865            let overshoot = start.0 - diff_transforms.start().0 .0;
5866            let start = diff_transforms.start().1 .0 + overshoot;
5867            diff_transforms.seek(&end, Bias::Right, &());
5868            let overshoot = end.0 - diff_transforms.start().0 .0;
5869            let end = diff_transforms.start().1 .0 + overshoot;
5870            Some(start..end)
5871        } else {
5872            None
5873        }
5874    }
5875
5876    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5877        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5878        let locator = self.excerpt_locator_for_id(excerpt_id);
5879        if cursor.seek(&Some(locator), Bias::Left, &()) {
5880            if let Some(excerpt) = cursor.item() {
5881                return Some(excerpt.range.context.clone());
5882            }
5883        }
5884        None
5885    }
5886
5887    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5888        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5889        let locator = self.excerpt_locator_for_id(excerpt_id);
5890        cursor.seek(&Some(locator), Bias::Left, &());
5891        if let Some(excerpt) = cursor.item() {
5892            if excerpt.id == excerpt_id {
5893                return Some(excerpt);
5894            }
5895        }
5896        None
5897    }
5898
5899    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5900    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5901        let range = range.start.to_offset(self)..range.end.to_offset(self);
5902        let mut cursor = self.cursor::<usize>();
5903        cursor.seek(&range.start);
5904
5905        let start_excerpt = cursor.excerpt()?;
5906        if range.end != range.start {
5907            cursor.seek_forward(&range.end);
5908            if cursor.excerpt()?.id != start_excerpt.id {
5909                return None;
5910            }
5911        }
5912
5913        cursor.seek_to_start_of_current_excerpt();
5914        let region = cursor.region()?;
5915        let offset = region.range.start;
5916        let buffer_offset = region.buffer_range.start;
5917        let excerpt_offset = cursor.excerpts.start().clone();
5918        Some(MultiBufferExcerpt {
5919            diff_transforms: cursor.diff_transforms,
5920            excerpt: start_excerpt,
5921            offset,
5922            buffer_offset,
5923            excerpt_offset,
5924        })
5925    }
5926
5927    pub fn selections_in_range<'a>(
5928        &'a self,
5929        range: &'a Range<Anchor>,
5930        include_local: bool,
5931    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5932        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5933        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5934        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5935        cursor.seek(start_locator, Bias::Left, &());
5936        cursor
5937            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5938            .flat_map(move |excerpt| {
5939                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5940                if excerpt.id == range.start.excerpt_id {
5941                    query_range.start = range.start.text_anchor;
5942                }
5943                if excerpt.id == range.end.excerpt_id {
5944                    query_range.end = range.end.text_anchor;
5945                }
5946
5947                excerpt
5948                    .buffer
5949                    .selections_in_range(query_range, include_local)
5950                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5951                        selections.map(move |selection| {
5952                            let mut start = Anchor {
5953                                buffer_id: Some(excerpt.buffer_id),
5954                                excerpt_id: excerpt.id,
5955                                text_anchor: selection.start,
5956                                diff_base_anchor: None,
5957                            };
5958                            let mut end = Anchor {
5959                                buffer_id: Some(excerpt.buffer_id),
5960                                excerpt_id: excerpt.id,
5961                                text_anchor: selection.end,
5962                                diff_base_anchor: None,
5963                            };
5964                            if range.start.cmp(&start, self).is_gt() {
5965                                start = range.start;
5966                            }
5967                            if range.end.cmp(&end, self).is_lt() {
5968                                end = range.end;
5969                            }
5970
5971                            (
5972                                replica_id,
5973                                line_mode,
5974                                cursor_shape,
5975                                Selection {
5976                                    id: selection.id,
5977                                    start,
5978                                    end,
5979                                    reversed: selection.reversed,
5980                                    goal: selection.goal,
5981                                },
5982                            )
5983                        })
5984                    })
5985            })
5986    }
5987
5988    pub fn show_headers(&self) -> bool {
5989        self.show_headers
5990    }
5991
5992    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5993        self.diffs.get(&buffer_id)
5994    }
5995}
5996
5997#[cfg(any(test, feature = "test-support"))]
5998impl MultiBufferSnapshot {
5999    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6000        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6001        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6002        start..end
6003    }
6004
6005    #[cfg(any(test, feature = "test-support"))]
6006    fn check_invariants(&self) {
6007        let excerpts = self.excerpts.items(&());
6008        let excerpt_ids = self.excerpt_ids.items(&());
6009
6010        for (ix, excerpt) in excerpts.iter().enumerate() {
6011            if ix == 0 {
6012                if excerpt.locator <= Locator::min() {
6013                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6014                }
6015            } else if excerpt.locator <= excerpts[ix - 1].locator {
6016                panic!("excerpts are out-of-order: {:?}", excerpts);
6017            }
6018        }
6019
6020        for (ix, entry) in excerpt_ids.iter().enumerate() {
6021            if ix == 0 {
6022                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6023                    panic!("invalid first excerpt id {:?}", entry.id);
6024                }
6025            } else if entry.id <= excerpt_ids[ix - 1].id {
6026                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6027            }
6028        }
6029
6030        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6031            panic!(
6032                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6033                self.excerpts.summary().text.len,
6034                self.diff_transforms.summary().input,
6035                self.diff_transforms.items(&()),
6036            );
6037        }
6038
6039        let mut prev_transform: Option<&DiffTransform> = None;
6040        for item in self.diff_transforms.iter() {
6041            if let DiffTransform::BufferContent {
6042                summary,
6043                inserted_hunk_info,
6044            } = item
6045            {
6046                if let Some(DiffTransform::BufferContent {
6047                    inserted_hunk_info: prev_inserted_hunk_info,
6048                    ..
6049                }) = prev_transform
6050                {
6051                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6052                        panic!(
6053                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6054                            self.diff_transforms.items(&()));
6055                    }
6056                }
6057                if summary.len == 0 && !self.is_empty() {
6058                    panic!("empty buffer content transform");
6059                }
6060            }
6061            prev_transform = Some(item);
6062        }
6063    }
6064}
6065
6066impl<'a, D> MultiBufferCursor<'a, D>
6067where
6068    D: TextDimension + Ord + Sub<D, Output = D>,
6069{
6070    fn seek(&mut self, position: &D) {
6071        self.cached_region.take();
6072        self.diff_transforms
6073            .seek(&OutputDimension(*position), Bias::Right, &());
6074        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6075            self.diff_transforms.prev(&());
6076        }
6077
6078        let mut excerpt_position = self.diff_transforms.start().1 .0;
6079        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6080            let overshoot = *position - self.diff_transforms.start().0 .0;
6081            excerpt_position.add_assign(&overshoot);
6082        }
6083
6084        self.excerpts
6085            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6086        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6087            self.excerpts.prev(&());
6088        }
6089    }
6090
6091    fn seek_forward(&mut self, position: &D) {
6092        self.cached_region.take();
6093        self.diff_transforms
6094            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6095        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6096            self.diff_transforms.prev(&());
6097        }
6098
6099        let overshoot = *position - self.diff_transforms.start().0 .0;
6100        let mut excerpt_position = self.diff_transforms.start().1 .0;
6101        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6102            excerpt_position.add_assign(&overshoot);
6103        }
6104
6105        self.excerpts
6106            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6107        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6108            self.excerpts.prev(&());
6109        }
6110    }
6111
6112    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
6113        self.cached_region.take();
6114        if let Some(excerpt) = self.excerpts.item() {
6115            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
6116            let position_in_excerpt = *position - excerpt_start;
6117            let mut excerpt_position = self.excerpts.start().0;
6118            excerpt_position.add_assign(&position_in_excerpt);
6119            self.diff_transforms
6120                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
6121            if self.diff_transforms.item().is_none() {
6122                self.diff_transforms.next(&());
6123            }
6124        }
6125    }
6126
6127    fn next_excerpt(&mut self) {
6128        self.excerpts.next(&());
6129        self.seek_to_start_of_current_excerpt();
6130    }
6131
6132    fn prev_excerpt(&mut self) {
6133        self.excerpts.prev(&());
6134        self.seek_to_start_of_current_excerpt();
6135    }
6136
6137    fn seek_to_start_of_current_excerpt(&mut self) {
6138        self.cached_region.take();
6139        self.diff_transforms
6140            .seek(self.excerpts.start(), Bias::Left, &());
6141        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6142            && self.diff_transforms.start().1 < *self.excerpts.start()
6143            && self.diff_transforms.next_item().is_some()
6144        {
6145            self.diff_transforms.next(&());
6146        }
6147    }
6148
6149    fn next(&mut self) {
6150        self.cached_region.take();
6151        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6152            cmp::Ordering::Less => self.diff_transforms.next(&()),
6153            cmp::Ordering::Greater => self.excerpts.next(&()),
6154            cmp::Ordering::Equal => {
6155                self.diff_transforms.next(&());
6156                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6157                    || self.diff_transforms.item().is_none()
6158                {
6159                    self.excerpts.next(&());
6160                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6161                    self.diff_transforms.item()
6162                {
6163                    if self
6164                        .excerpts
6165                        .item()
6166                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6167                    {
6168                        self.excerpts.next(&());
6169                    }
6170                }
6171            }
6172        }
6173    }
6174
6175    fn prev(&mut self) {
6176        self.cached_region.take();
6177        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6178            cmp::Ordering::Less => self.excerpts.prev(&()),
6179            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6180            cmp::Ordering::Equal => {
6181                self.diff_transforms.prev(&());
6182                if self.diff_transforms.start().1 < *self.excerpts.start()
6183                    || self.diff_transforms.item().is_none()
6184                {
6185                    self.excerpts.prev(&());
6186                }
6187            }
6188        }
6189    }
6190
6191    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6192        if self.cached_region.is_none() {
6193            self.cached_region = self.build_region();
6194        }
6195        self.cached_region.clone()
6196    }
6197
6198    fn is_at_end_of_excerpt(&mut self) -> bool {
6199        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6200            return false;
6201        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6202            || self.diff_transforms.item().is_none()
6203        {
6204            return true;
6205        }
6206
6207        let next_transform = self.diff_transforms.next_item();
6208        next_transform.map_or(true, |next_transform| match next_transform {
6209            DiffTransform::BufferContent { .. } => true,
6210            DiffTransform::DeletedHunk { hunk_info, .. } => self
6211                .excerpts
6212                .item()
6213                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6214        })
6215    }
6216
6217    fn main_buffer_position(&self) -> Option<D> {
6218        let excerpt = self.excerpts.item()?;
6219        let buffer = &excerpt.buffer;
6220        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6221        let mut buffer_start = buffer_context_start;
6222        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6223        buffer_start.add_assign(&overshoot);
6224        Some(buffer_start)
6225    }
6226
6227    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6228        let excerpt = self.excerpts.item()?;
6229        match self.diff_transforms.item()? {
6230            DiffTransform::DeletedHunk {
6231                buffer_id,
6232                base_text_byte_range,
6233                has_trailing_newline,
6234                hunk_info,
6235                ..
6236            } => {
6237                let diff = self.diffs.get(&buffer_id)?;
6238                let buffer = diff.base_text()?;
6239                let mut rope_cursor = buffer.as_rope().cursor(0);
6240                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6241                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6242                let mut buffer_end = buffer_start;
6243                buffer_end.add_assign(&buffer_range_len);
6244                let start = self.diff_transforms.start().0 .0;
6245                let end = self.diff_transforms.end(&()).0 .0;
6246                return Some(MultiBufferRegion {
6247                    buffer,
6248                    excerpt,
6249                    has_trailing_newline: *has_trailing_newline,
6250                    is_main_buffer: false,
6251                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6252                        hunk_info.hunk_secondary_status,
6253                    )),
6254                    buffer_range: buffer_start..buffer_end,
6255                    range: start..end,
6256                });
6257            }
6258            DiffTransform::BufferContent {
6259                inserted_hunk_info, ..
6260            } => {
6261                let buffer = &excerpt.buffer;
6262                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6263
6264                let mut start = self.diff_transforms.start().0 .0;
6265                let mut buffer_start = buffer_context_start;
6266                if self.diff_transforms.start().1 < *self.excerpts.start() {
6267                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6268                    start.add_assign(&overshoot);
6269                } else {
6270                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6271                    buffer_start.add_assign(&overshoot);
6272                }
6273
6274                let mut end;
6275                let mut buffer_end;
6276                let has_trailing_newline;
6277                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6278                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6279                    end = self.diff_transforms.end(&()).0 .0;
6280                    buffer_end = buffer_context_start;
6281                    buffer_end.add_assign(&overshoot);
6282                    has_trailing_newline = false;
6283                } else {
6284                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6285                    end = self.diff_transforms.start().0 .0;
6286                    end.add_assign(&overshoot);
6287                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6288                    has_trailing_newline = excerpt.has_trailing_newline;
6289                };
6290
6291                Some(MultiBufferRegion {
6292                    buffer,
6293                    excerpt,
6294                    has_trailing_newline,
6295                    is_main_buffer: true,
6296                    diff_hunk_status: inserted_hunk_info
6297                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6298                    buffer_range: buffer_start..buffer_end,
6299                    range: start..end,
6300                })
6301            }
6302        }
6303    }
6304
6305    fn excerpt(&self) -> Option<&'a Excerpt> {
6306        self.excerpts.item()
6307    }
6308}
6309
6310impl History {
6311    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6312        self.transaction_depth += 1;
6313        if self.transaction_depth == 1 {
6314            let id = self.next_transaction_id.tick();
6315            self.undo_stack.push(Transaction {
6316                id,
6317                buffer_transactions: Default::default(),
6318                first_edit_at: now,
6319                last_edit_at: now,
6320                suppress_grouping: false,
6321            });
6322            Some(id)
6323        } else {
6324            None
6325        }
6326    }
6327
6328    fn end_transaction(
6329        &mut self,
6330        now: Instant,
6331        buffer_transactions: HashMap<BufferId, TransactionId>,
6332    ) -> bool {
6333        assert_ne!(self.transaction_depth, 0);
6334        self.transaction_depth -= 1;
6335        if self.transaction_depth == 0 {
6336            if buffer_transactions.is_empty() {
6337                self.undo_stack.pop();
6338                false
6339            } else {
6340                self.redo_stack.clear();
6341                let transaction = self.undo_stack.last_mut().unwrap();
6342                transaction.last_edit_at = now;
6343                for (buffer_id, transaction_id) in buffer_transactions {
6344                    transaction
6345                        .buffer_transactions
6346                        .entry(buffer_id)
6347                        .or_insert(transaction_id);
6348                }
6349                true
6350            }
6351        } else {
6352            false
6353        }
6354    }
6355
6356    fn push_transaction<'a, T>(
6357        &mut self,
6358        buffer_transactions: T,
6359        now: Instant,
6360        cx: &Context<MultiBuffer>,
6361    ) where
6362        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6363    {
6364        assert_eq!(self.transaction_depth, 0);
6365        let transaction = Transaction {
6366            id: self.next_transaction_id.tick(),
6367            buffer_transactions: buffer_transactions
6368                .into_iter()
6369                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6370                .collect(),
6371            first_edit_at: now,
6372            last_edit_at: now,
6373            suppress_grouping: false,
6374        };
6375        if !transaction.buffer_transactions.is_empty() {
6376            self.undo_stack.push(transaction);
6377            self.redo_stack.clear();
6378        }
6379    }
6380
6381    fn finalize_last_transaction(&mut self) {
6382        if let Some(transaction) = self.undo_stack.last_mut() {
6383            transaction.suppress_grouping = true;
6384        }
6385    }
6386
6387    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6388        if let Some(ix) = self
6389            .undo_stack
6390            .iter()
6391            .rposition(|transaction| transaction.id == transaction_id)
6392        {
6393            Some(self.undo_stack.remove(ix))
6394        } else if let Some(ix) = self
6395            .redo_stack
6396            .iter()
6397            .rposition(|transaction| transaction.id == transaction_id)
6398        {
6399            Some(self.redo_stack.remove(ix))
6400        } else {
6401            None
6402        }
6403    }
6404
6405    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6406        self.undo_stack
6407            .iter()
6408            .find(|transaction| transaction.id == transaction_id)
6409            .or_else(|| {
6410                self.redo_stack
6411                    .iter()
6412                    .find(|transaction| transaction.id == transaction_id)
6413            })
6414    }
6415
6416    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6417        self.undo_stack
6418            .iter_mut()
6419            .find(|transaction| transaction.id == transaction_id)
6420            .or_else(|| {
6421                self.redo_stack
6422                    .iter_mut()
6423                    .find(|transaction| transaction.id == transaction_id)
6424            })
6425    }
6426
6427    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6428        assert_eq!(self.transaction_depth, 0);
6429        if let Some(transaction) = self.undo_stack.pop() {
6430            self.redo_stack.push(transaction);
6431            self.redo_stack.last_mut()
6432        } else {
6433            None
6434        }
6435    }
6436
6437    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6438        assert_eq!(self.transaction_depth, 0);
6439        if let Some(transaction) = self.redo_stack.pop() {
6440            self.undo_stack.push(transaction);
6441            self.undo_stack.last_mut()
6442        } else {
6443            None
6444        }
6445    }
6446
6447    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6448        let ix = self
6449            .undo_stack
6450            .iter()
6451            .rposition(|transaction| transaction.id == transaction_id)?;
6452        let transaction = self.undo_stack.remove(ix);
6453        self.redo_stack.push(transaction);
6454        self.redo_stack.last()
6455    }
6456
6457    fn group(&mut self) -> Option<TransactionId> {
6458        let mut count = 0;
6459        let mut transactions = self.undo_stack.iter();
6460        if let Some(mut transaction) = transactions.next_back() {
6461            while let Some(prev_transaction) = transactions.next_back() {
6462                if !prev_transaction.suppress_grouping
6463                    && transaction.first_edit_at - prev_transaction.last_edit_at
6464                        <= self.group_interval
6465                {
6466                    transaction = prev_transaction;
6467                    count += 1;
6468                } else {
6469                    break;
6470                }
6471            }
6472        }
6473        self.group_trailing(count)
6474    }
6475
6476    fn group_until(&mut self, transaction_id: TransactionId) {
6477        let mut count = 0;
6478        for transaction in self.undo_stack.iter().rev() {
6479            if transaction.id == transaction_id {
6480                self.group_trailing(count);
6481                break;
6482            } else if transaction.suppress_grouping {
6483                break;
6484            } else {
6485                count += 1;
6486            }
6487        }
6488    }
6489
6490    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6491        let new_len = self.undo_stack.len() - n;
6492        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6493        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6494            if let Some(transaction) = transactions_to_merge.last() {
6495                last_transaction.last_edit_at = transaction.last_edit_at;
6496            }
6497            for to_merge in transactions_to_merge {
6498                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6499                    last_transaction
6500                        .buffer_transactions
6501                        .entry(*buffer_id)
6502                        .or_insert(*transaction_id);
6503                }
6504            }
6505        }
6506
6507        self.undo_stack.truncate(new_len);
6508        self.undo_stack.last().map(|t| t.id)
6509    }
6510}
6511
6512impl Excerpt {
6513    fn new(
6514        id: ExcerptId,
6515        locator: Locator,
6516        buffer_id: BufferId,
6517        buffer: BufferSnapshot,
6518        range: ExcerptRange<text::Anchor>,
6519        has_trailing_newline: bool,
6520    ) -> Self {
6521        Excerpt {
6522            id,
6523            locator,
6524            max_buffer_row: range.context.end.to_point(&buffer).row,
6525            text_summary: buffer
6526                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6527            buffer_id,
6528            buffer,
6529            range,
6530            has_trailing_newline,
6531        }
6532    }
6533
6534    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6535        let content_start = self.range.context.start.to_offset(&self.buffer);
6536        let chunks_start = content_start + range.start;
6537        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6538
6539        let footer_height = if self.has_trailing_newline
6540            && range.start <= self.text_summary.len
6541            && range.end > self.text_summary.len
6542        {
6543            1
6544        } else {
6545            0
6546        };
6547
6548        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6549
6550        ExcerptChunks {
6551            excerpt_id: self.id,
6552            content_chunks,
6553            footer_height,
6554        }
6555    }
6556
6557    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6558        let content_start = self.range.context.start.to_offset(&self.buffer);
6559        let chunks_start = content_start + range.start;
6560        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6561        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6562        excerpt_chunks.footer_height = if self.has_trailing_newline
6563            && range.start <= self.text_summary.len
6564            && range.end > self.text_summary.len
6565        {
6566            1
6567        } else {
6568            0
6569        };
6570    }
6571
6572    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6573        if text_anchor
6574            .cmp(&self.range.context.start, &self.buffer)
6575            .is_lt()
6576        {
6577            self.range.context.start
6578        } else if text_anchor
6579            .cmp(&self.range.context.end, &self.buffer)
6580            .is_gt()
6581        {
6582            self.range.context.end
6583        } else {
6584            text_anchor
6585        }
6586    }
6587
6588    fn contains(&self, anchor: &Anchor) -> bool {
6589        Some(self.buffer_id) == anchor.buffer_id
6590            && self
6591                .range
6592                .context
6593                .start
6594                .cmp(&anchor.text_anchor, &self.buffer)
6595                .is_le()
6596            && self
6597                .range
6598                .context
6599                .end
6600                .cmp(&anchor.text_anchor, &self.buffer)
6601                .is_ge()
6602    }
6603
6604    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6605    fn buffer_start_offset(&self) -> usize {
6606        self.range.context.start.to_offset(&self.buffer)
6607    }
6608
6609    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6610    fn buffer_end_offset(&self) -> usize {
6611        self.buffer_start_offset() + self.text_summary.len
6612    }
6613}
6614
6615impl<'a> MultiBufferExcerpt<'a> {
6616    pub fn id(&self) -> ExcerptId {
6617        self.excerpt.id
6618    }
6619
6620    pub fn buffer_id(&self) -> BufferId {
6621        self.excerpt.buffer_id
6622    }
6623
6624    pub fn start_anchor(&self) -> Anchor {
6625        Anchor {
6626            buffer_id: Some(self.excerpt.buffer_id),
6627            excerpt_id: self.excerpt.id,
6628            text_anchor: self.excerpt.range.context.start,
6629            diff_base_anchor: None,
6630        }
6631    }
6632
6633    pub fn end_anchor(&self) -> Anchor {
6634        Anchor {
6635            buffer_id: Some(self.excerpt.buffer_id),
6636            excerpt_id: self.excerpt.id,
6637            text_anchor: self.excerpt.range.context.end,
6638            diff_base_anchor: None,
6639        }
6640    }
6641
6642    pub fn buffer(&self) -> &'a BufferSnapshot {
6643        &self.excerpt.buffer
6644    }
6645
6646    pub fn buffer_range(&self) -> Range<usize> {
6647        self.buffer_offset
6648            ..self
6649                .excerpt
6650                .range
6651                .context
6652                .end
6653                .to_offset(&self.excerpt.buffer.text)
6654    }
6655
6656    pub fn start_offset(&self) -> usize {
6657        self.offset
6658    }
6659
6660    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6661    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6662        self.map_range_to_buffer(offset..offset).start
6663    }
6664
6665    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6666    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6667        self.diff_transforms
6668            .seek(&OutputDimension(range.start), Bias::Right, &());
6669        let start = self.map_offset_to_buffer_internal(range.start);
6670        let end = if range.end > range.start {
6671            self.diff_transforms
6672                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6673            self.map_offset_to_buffer_internal(range.end)
6674        } else {
6675            start
6676        };
6677        start..end
6678    }
6679
6680    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6681        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6682        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6683            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6684        };
6685        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6686        self.buffer_offset + offset_in_excerpt
6687    }
6688
6689    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6690    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6691        self.map_range_from_buffer(buffer_offset..buffer_offset)
6692            .start
6693    }
6694
6695    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6696    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6697        if buffer_range.start < self.buffer_offset {
6698            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6699            return buffer_range;
6700        }
6701        let overshoot = buffer_range.start - self.buffer_offset;
6702        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6703        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6704        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6705            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6706            return buffer_range;
6707        }
6708        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6709        let start = self.diff_transforms.start().0 .0 + overshoot;
6710
6711        let end = if buffer_range.end > buffer_range.start {
6712            let overshoot = buffer_range.end - self.buffer_offset;
6713            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6714            self.diff_transforms
6715                .seek_forward(&excerpt_offset, Bias::Right, &());
6716            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6717            self.diff_transforms.start().0 .0 + overshoot
6718        } else {
6719            start
6720        };
6721
6722        start..end
6723    }
6724
6725    /// Returns true if the entirety of the given range is in the buffer's excerpt
6726    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6727        range.start >= self.excerpt.buffer_start_offset()
6728            && range.end <= self.excerpt.buffer_end_offset()
6729    }
6730
6731    pub fn max_buffer_row(&self) -> u32 {
6732        self.excerpt.max_buffer_row
6733    }
6734}
6735
6736impl ExcerptId {
6737    pub fn min() -> Self {
6738        Self(0)
6739    }
6740
6741    pub fn max() -> Self {
6742        Self(usize::MAX)
6743    }
6744
6745    pub fn to_proto(&self) -> u64 {
6746        self.0 as _
6747    }
6748
6749    pub fn from_proto(proto: u64) -> Self {
6750        Self(proto as _)
6751    }
6752
6753    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6754        let a = snapshot.excerpt_locator_for_id(*self);
6755        let b = snapshot.excerpt_locator_for_id(*other);
6756        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6757    }
6758}
6759
6760impl From<ExcerptId> for usize {
6761    fn from(val: ExcerptId) -> Self {
6762        val.0
6763    }
6764}
6765
6766impl fmt::Debug for Excerpt {
6767    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6768        f.debug_struct("Excerpt")
6769            .field("id", &self.id)
6770            .field("locator", &self.locator)
6771            .field("buffer_id", &self.buffer_id)
6772            .field("range", &self.range)
6773            .field("text_summary", &self.text_summary)
6774            .field("has_trailing_newline", &self.has_trailing_newline)
6775            .finish()
6776    }
6777}
6778
6779impl sum_tree::Item for Excerpt {
6780    type Summary = ExcerptSummary;
6781
6782    fn summary(&self, _cx: &()) -> Self::Summary {
6783        let mut text = self.text_summary;
6784        if self.has_trailing_newline {
6785            text += TextSummary::from("\n");
6786        }
6787        ExcerptSummary {
6788            excerpt_id: self.id,
6789            excerpt_locator: self.locator.clone(),
6790            widest_line_number: self.max_buffer_row,
6791            text,
6792        }
6793    }
6794}
6795
6796impl sum_tree::Item for ExcerptIdMapping {
6797    type Summary = ExcerptId;
6798
6799    fn summary(&self, _cx: &()) -> Self::Summary {
6800        self.id
6801    }
6802}
6803
6804impl sum_tree::KeyedItem for ExcerptIdMapping {
6805    type Key = ExcerptId;
6806
6807    fn key(&self) -> Self::Key {
6808        self.id
6809    }
6810}
6811
6812impl DiffTransform {
6813    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6814        match self {
6815            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6816            DiffTransform::BufferContent {
6817                inserted_hunk_info, ..
6818            } => *inserted_hunk_info,
6819        }
6820    }
6821}
6822
6823impl sum_tree::Item for DiffTransform {
6824    type Summary = DiffTransformSummary;
6825
6826    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6827        match self {
6828            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6829                input: *summary,
6830                output: *summary,
6831            },
6832            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6833                input: TextSummary::default(),
6834                output: *summary,
6835            },
6836        }
6837    }
6838}
6839
6840impl DiffTransformSummary {
6841    fn excerpt_len(&self) -> ExcerptOffset {
6842        ExcerptOffset::new(self.input.len)
6843    }
6844}
6845
6846impl sum_tree::Summary for DiffTransformSummary {
6847    type Context = ();
6848
6849    fn zero(_: &Self::Context) -> Self {
6850        DiffTransformSummary {
6851            input: TextSummary::default(),
6852            output: TextSummary::default(),
6853        }
6854    }
6855
6856    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6857        self.input += &summary.input;
6858        self.output += &summary.output;
6859    }
6860}
6861
6862impl sum_tree::Summary for ExcerptId {
6863    type Context = ();
6864
6865    fn zero(_cx: &()) -> Self {
6866        Default::default()
6867    }
6868
6869    fn add_summary(&mut self, other: &Self, _: &()) {
6870        *self = *other;
6871    }
6872}
6873
6874impl sum_tree::Summary for ExcerptSummary {
6875    type Context = ();
6876
6877    fn zero(_cx: &()) -> Self {
6878        Default::default()
6879    }
6880
6881    fn add_summary(&mut self, summary: &Self, _: &()) {
6882        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6883        self.excerpt_locator = summary.excerpt_locator.clone();
6884        self.text.add_summary(&summary.text, &());
6885        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6886    }
6887}
6888
6889impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6890    fn zero(_cx: &()) -> Self {
6891        Default::default()
6892    }
6893
6894    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6895        self.value += summary.text.len;
6896    }
6897}
6898
6899impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6900    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6901        Ord::cmp(&self.value, &cursor_location.text.len)
6902    }
6903}
6904
6905impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6906    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6907        Ord::cmp(&Some(self), cursor_location)
6908    }
6909}
6910
6911impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6912    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6913        Ord::cmp(self, &cursor_location.excerpt_locator)
6914    }
6915}
6916
6917impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6918    fn zero(_cx: &()) -> Self {
6919        Default::default()
6920    }
6921
6922    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6923        self.value += summary.text.lines;
6924    }
6925}
6926
6927impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6928    for ExcerptDimension<D>
6929{
6930    fn zero(_: &()) -> Self {
6931        ExcerptDimension(D::default())
6932    }
6933
6934    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6935        self.0.add_assign(&D::from_text_summary(&summary.text))
6936    }
6937}
6938
6939impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6940    fn zero(_cx: &()) -> Self {
6941        Default::default()
6942    }
6943
6944    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6945        *self = Some(&summary.excerpt_locator);
6946    }
6947}
6948
6949impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6950    fn zero(_cx: &()) -> Self {
6951        Default::default()
6952    }
6953
6954    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6955        *self = Some(summary.excerpt_id);
6956    }
6957}
6958
6959#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6960struct ExcerptDimension<T>(T);
6961
6962#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6963struct OutputDimension<T>(T);
6964
6965impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6966    fn zero(_: &()) -> Self {
6967        ExcerptOffset::new(0)
6968    }
6969
6970    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6971        self.value += summary.input.len;
6972    }
6973}
6974
6975impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6976    fn zero(_: &()) -> Self {
6977        ExcerptPoint::new(0, 0)
6978    }
6979
6980    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6981        self.value += summary.input.lines;
6982    }
6983}
6984
6985impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6986    for ExcerptDimension<D>
6987{
6988    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6989        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6990    }
6991}
6992
6993impl<D: TextDimension + Ord>
6994    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6995    for ExcerptDimension<D>
6996{
6997    fn cmp(
6998        &self,
6999        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7000        _: &(),
7001    ) -> cmp::Ordering {
7002        Ord::cmp(&self.0, &cursor_location.1 .0)
7003    }
7004}
7005
7006impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7007    fn zero(_: &()) -> Self {
7008        ExcerptDimension(D::default())
7009    }
7010
7011    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7012        self.0.add_assign(&D::from_text_summary(&summary.input))
7013    }
7014}
7015
7016impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7017    fn zero(_: &()) -> Self {
7018        OutputDimension(D::default())
7019    }
7020
7021    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7022        self.0.add_assign(&D::from_text_summary(&summary.output))
7023    }
7024}
7025
7026impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7027    fn zero(_: &()) -> Self {
7028        TextSummary::default()
7029    }
7030
7031    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7032        *self += summary.output
7033    }
7034}
7035
7036impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7037    fn zero(_: &()) -> Self {
7038        0
7039    }
7040
7041    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7042        *self += summary.output.len
7043    }
7044}
7045
7046impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7047    fn zero(_: &()) -> Self {
7048        Point::new(0, 0)
7049    }
7050
7051    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7052        *self += summary.output.lines
7053    }
7054}
7055
7056impl MultiBufferRows<'_> {
7057    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7058        self.point = Point::new(row, 0);
7059        self.cursor.seek(&self.point);
7060    }
7061}
7062
7063impl Iterator for MultiBufferRows<'_> {
7064    type Item = RowInfo;
7065
7066    fn next(&mut self) -> Option<Self::Item> {
7067        if self.is_empty && self.point.row == 0 {
7068            self.point += Point::new(1, 0);
7069            return Some(RowInfo {
7070                buffer_id: None,
7071                buffer_row: Some(0),
7072                multibuffer_row: Some(MultiBufferRow(0)),
7073                diff_status: None,
7074            });
7075        }
7076
7077        let mut region = self.cursor.region()?;
7078        while self.point >= region.range.end {
7079            self.cursor.next();
7080            if let Some(next_region) = self.cursor.region() {
7081                region = next_region;
7082            } else {
7083                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7084                    let multibuffer_row = MultiBufferRow(self.point.row);
7085                    self.point += Point::new(1, 0);
7086                    let last_excerpt = self
7087                        .cursor
7088                        .excerpts
7089                        .item()
7090                        .or(self.cursor.excerpts.prev_item())?;
7091                    let last_row = last_excerpt
7092                        .range
7093                        .context
7094                        .end
7095                        .to_point(&last_excerpt.buffer)
7096                        .row;
7097                    return Some(RowInfo {
7098                        buffer_id: Some(last_excerpt.buffer_id),
7099                        buffer_row: Some(last_row),
7100                        multibuffer_row: Some(multibuffer_row),
7101                        diff_status: None,
7102                    });
7103                } else {
7104                    return None;
7105                }
7106            };
7107        }
7108
7109        let overshoot = self.point - region.range.start;
7110        let buffer_point = region.buffer_range.start + overshoot;
7111        let result = Some(RowInfo {
7112            buffer_id: Some(region.buffer.remote_id()),
7113            buffer_row: Some(buffer_point.row),
7114            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7115            diff_status: region
7116                .diff_hunk_status
7117                .filter(|_| self.point < region.range.end),
7118        });
7119        self.point += Point::new(1, 0);
7120        result
7121    }
7122}
7123
7124impl<'a> MultiBufferChunks<'a> {
7125    pub fn offset(&self) -> usize {
7126        self.range.start
7127    }
7128
7129    pub fn seek(&mut self, range: Range<usize>) {
7130        self.diff_transforms.seek(&range.end, Bias::Right, &());
7131        let mut excerpt_end = self.diff_transforms.start().1;
7132        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7133            let overshoot = range.end - self.diff_transforms.start().0;
7134            excerpt_end.value += overshoot;
7135        }
7136
7137        self.diff_transforms.seek(&range.start, Bias::Right, &());
7138        let mut excerpt_start = self.diff_transforms.start().1;
7139        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7140            let overshoot = range.start - self.diff_transforms.start().0;
7141            excerpt_start.value += overshoot;
7142        }
7143
7144        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7145        self.buffer_chunk.take();
7146        self.range = range;
7147    }
7148
7149    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7150        self.excerpt_offset_range = new_range.clone();
7151        self.excerpts.seek(&new_range.start, Bias::Right, &());
7152        if let Some(excerpt) = self.excerpts.item() {
7153            let excerpt_start = *self.excerpts.start();
7154            if let Some(excerpt_chunks) = self
7155                .excerpt_chunks
7156                .as_mut()
7157                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7158            {
7159                excerpt.seek_chunks(
7160                    excerpt_chunks,
7161                    (self.excerpt_offset_range.start - excerpt_start).value
7162                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7163                );
7164            } else {
7165                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7166                    (self.excerpt_offset_range.start - excerpt_start).value
7167                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7168                    self.language_aware,
7169                ));
7170            }
7171        } else {
7172            self.excerpt_chunks = None;
7173        }
7174    }
7175
7176    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7177        loop {
7178            if self.excerpt_offset_range.is_empty() {
7179                return None;
7180            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7181                self.excerpt_offset_range.start.value += chunk.text.len();
7182                return Some(chunk);
7183            } else {
7184                self.excerpts.next(&());
7185                let excerpt = self.excerpts.item()?;
7186                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7187                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7188                    self.language_aware,
7189                ));
7190            }
7191        }
7192    }
7193}
7194
7195impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7196    type Item = &'a str;
7197
7198    fn next(&mut self) -> Option<Self::Item> {
7199        let mut region = self.cursor.region()?;
7200        if self.offset == region.range.start {
7201            self.cursor.prev();
7202            region = self.cursor.region()?;
7203            let start_overshoot = self.start.saturating_sub(region.range.start);
7204            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7205                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7206            ));
7207        }
7208
7209        if self.offset == region.range.end && region.has_trailing_newline {
7210            self.offset -= 1;
7211            Some("\n")
7212        } else {
7213            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7214            self.offset -= chunk.len();
7215            Some(chunk)
7216        }
7217    }
7218}
7219
7220impl<'a> Iterator for MultiBufferChunks<'a> {
7221    type Item = Chunk<'a>;
7222
7223    fn next(&mut self) -> Option<Chunk<'a>> {
7224        if self.range.start >= self.range.end {
7225            return None;
7226        }
7227        if self.range.start == self.diff_transforms.end(&()).0 {
7228            self.diff_transforms.next(&());
7229        }
7230
7231        let diff_transform_start = self.diff_transforms.start().0;
7232        let diff_transform_end = self.diff_transforms.end(&()).0;
7233        debug_assert!(self.range.start < diff_transform_end);
7234
7235        let diff_transform = self.diff_transforms.item()?;
7236        match diff_transform {
7237            DiffTransform::BufferContent { .. } => {
7238                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7239                    chunk
7240                } else {
7241                    let chunk = self.next_excerpt_chunk().unwrap();
7242                    self.buffer_chunk.insert(chunk)
7243                };
7244
7245                let chunk_end = self.range.start + chunk.text.len();
7246                let diff_transform_end = diff_transform_end.min(self.range.end);
7247
7248                if diff_transform_end < chunk_end {
7249                    let (before, after) =
7250                        chunk.text.split_at(diff_transform_end - self.range.start);
7251                    self.range.start = diff_transform_end;
7252                    chunk.text = after;
7253                    Some(Chunk {
7254                        text: before,
7255                        ..chunk.clone()
7256                    })
7257                } else {
7258                    self.range.start = chunk_end;
7259                    self.buffer_chunk.take()
7260                }
7261            }
7262            DiffTransform::DeletedHunk {
7263                buffer_id,
7264                base_text_byte_range,
7265                has_trailing_newline,
7266                ..
7267            } => {
7268                let base_text_start =
7269                    base_text_byte_range.start + self.range.start - diff_transform_start;
7270                let base_text_end =
7271                    base_text_byte_range.start + self.range.end - diff_transform_start;
7272                let base_text_end = base_text_end.min(base_text_byte_range.end);
7273
7274                let mut chunks = if let Some((_, mut chunks)) = self
7275                    .diff_base_chunks
7276                    .take()
7277                    .filter(|(id, _)| id == buffer_id)
7278                {
7279                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7280                    {
7281                        chunks.seek(base_text_start..base_text_end);
7282                    }
7283                    chunks
7284                } else {
7285                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text()?;
7286                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7287                };
7288
7289                let chunk = if let Some(chunk) = chunks.next() {
7290                    self.range.start += chunk.text.len();
7291                    self.diff_base_chunks = Some((*buffer_id, chunks));
7292                    chunk
7293                } else {
7294                    debug_assert!(has_trailing_newline);
7295                    self.range.start += "\n".len();
7296                    Chunk {
7297                        text: "\n",
7298                        ..Default::default()
7299                    }
7300                };
7301                Some(chunk)
7302            }
7303        }
7304    }
7305}
7306
7307impl MultiBufferBytes<'_> {
7308    fn consume(&mut self, len: usize) {
7309        self.range.start += len;
7310        self.chunk = &self.chunk[len..];
7311
7312        if !self.range.is_empty() && self.chunk.is_empty() {
7313            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7314                self.chunk = chunk;
7315            } else if self.has_trailing_newline {
7316                self.has_trailing_newline = false;
7317                self.chunk = b"\n";
7318            } else {
7319                self.cursor.next();
7320                if let Some(region) = self.cursor.region() {
7321                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7322                        region.buffer_range.start
7323                            ..(region.buffer_range.start + self.range.end - region.range.start)
7324                                .min(region.buffer_range.end),
7325                    );
7326                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7327                    self.excerpt_bytes = Some(excerpt_bytes);
7328                    self.has_trailing_newline =
7329                        region.has_trailing_newline && self.range.end >= region.range.end;
7330                    if self.chunk.is_empty() && self.has_trailing_newline {
7331                        self.has_trailing_newline = false;
7332                        self.chunk = b"\n";
7333                    }
7334                }
7335            }
7336        }
7337    }
7338}
7339
7340impl<'a> Iterator for MultiBufferBytes<'a> {
7341    type Item = &'a [u8];
7342
7343    fn next(&mut self) -> Option<Self::Item> {
7344        let chunk = self.chunk;
7345        if chunk.is_empty() {
7346            None
7347        } else {
7348            self.consume(chunk.len());
7349            Some(chunk)
7350        }
7351    }
7352}
7353
7354impl io::Read for MultiBufferBytes<'_> {
7355    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7356        let len = cmp::min(buf.len(), self.chunk.len());
7357        buf[..len].copy_from_slice(&self.chunk[..len]);
7358        if len > 0 {
7359            self.consume(len);
7360        }
7361        Ok(len)
7362    }
7363}
7364
7365impl io::Read for ReversedMultiBufferBytes<'_> {
7366    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7367        let len = cmp::min(buf.len(), self.chunk.len());
7368        buf[..len].copy_from_slice(&self.chunk[..len]);
7369        buf[..len].reverse();
7370        if len > 0 {
7371            self.range.end -= len;
7372            self.chunk = &self.chunk[..self.chunk.len() - len];
7373            if !self.range.is_empty() && self.chunk.is_empty() {
7374                if let Some(chunk) = self.chunks.next() {
7375                    self.chunk = chunk.as_bytes();
7376                }
7377            }
7378        }
7379        Ok(len)
7380    }
7381}
7382
7383impl<'a> Iterator for ExcerptChunks<'a> {
7384    type Item = Chunk<'a>;
7385
7386    fn next(&mut self) -> Option<Self::Item> {
7387        if let Some(chunk) = self.content_chunks.next() {
7388            return Some(chunk);
7389        }
7390
7391        if self.footer_height > 0 {
7392            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7393            self.footer_height = 0;
7394            return Some(Chunk {
7395                text,
7396                ..Default::default()
7397            });
7398        }
7399
7400        None
7401    }
7402}
7403
7404impl ToOffset for Point {
7405    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7406        snapshot.point_to_offset(*self)
7407    }
7408}
7409
7410impl ToOffset for usize {
7411    #[track_caller]
7412    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7413        assert!(*self <= snapshot.len(), "offset is out of range");
7414        *self
7415    }
7416}
7417
7418impl ToOffset for OffsetUtf16 {
7419    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7420        snapshot.offset_utf16_to_offset(*self)
7421    }
7422}
7423
7424impl ToOffset for PointUtf16 {
7425    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7426        snapshot.point_utf16_to_offset(*self)
7427    }
7428}
7429
7430impl ToOffsetUtf16 for OffsetUtf16 {
7431    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7432        *self
7433    }
7434}
7435
7436impl ToOffsetUtf16 for usize {
7437    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7438        snapshot.offset_to_offset_utf16(*self)
7439    }
7440}
7441
7442impl ToPoint for usize {
7443    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7444        snapshot.offset_to_point(*self)
7445    }
7446}
7447
7448impl ToPoint for Point {
7449    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7450        *self
7451    }
7452}
7453
7454impl ToPointUtf16 for usize {
7455    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7456        snapshot.offset_to_point_utf16(*self)
7457    }
7458}
7459
7460impl ToPointUtf16 for Point {
7461    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7462        snapshot.point_to_point_utf16(*self)
7463    }
7464}
7465
7466impl ToPointUtf16 for PointUtf16 {
7467    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7468        *self
7469    }
7470}
7471
7472impl From<ExcerptId> for EntityId {
7473    fn from(id: ExcerptId) -> Self {
7474        EntityId::from(id.0 as u64)
7475    }
7476}
7477
7478pub fn build_excerpt_ranges<T>(
7479    buffer: &BufferSnapshot,
7480    ranges: &[Range<T>],
7481    context_line_count: u32,
7482) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7483where
7484    T: text::ToPoint,
7485{
7486    let max_point = buffer.max_point();
7487    let mut range_counts = Vec::new();
7488    let mut excerpt_ranges = Vec::new();
7489    let mut range_iter = ranges
7490        .iter()
7491        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7492        .peekable();
7493    while let Some(range) = range_iter.next() {
7494        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7495        let row = (range.end.row + context_line_count).min(max_point.row);
7496        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7497
7498        let mut ranges_in_excerpt = 1;
7499
7500        while let Some(next_range) = range_iter.peek() {
7501            if next_range.start.row <= excerpt_end.row + context_line_count {
7502                let row = (next_range.end.row + context_line_count).min(max_point.row);
7503                excerpt_end = Point::new(row, buffer.line_len(row));
7504
7505                ranges_in_excerpt += 1;
7506                range_iter.next();
7507            } else {
7508                break;
7509            }
7510        }
7511
7512        excerpt_ranges.push(ExcerptRange {
7513            context: excerpt_start..excerpt_end,
7514            primary: Some(range),
7515        });
7516        range_counts.push(ranges_in_excerpt);
7517    }
7518
7519    (excerpt_ranges, range_counts)
7520}