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::{Result, anyhow};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{SinkExt, channel::mpsc};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  21    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  22    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  23    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  24    Unclipped,
  25    language_settings::{IndentGuideSettings, LanguageSettings, language_settings},
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{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    rc::Rc,
  43    str,
  44    sync::Arc,
  45    time::{Duration, Instant},
  46};
  47use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  48use text::{
  49    BufferId, Edit, LineIndent, TextSummary,
  50    locator::Locator,
  51    subscription::{Subscription, Topic},
  52};
  53use theme::SyntaxTheme;
  54use util::post_inc;
  55
  56const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  57
  58#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  59pub struct ExcerptId(usize);
  60
  61/// One or more [`Buffers`](Buffer) being edited in a single view.
  62///
  63/// See <https://zed.dev/features#multi-buffers>
  64pub struct MultiBuffer {
  65    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  66    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  67    snapshot: RefCell<MultiBufferSnapshot>,
  68    /// Contains the state of the buffers being edited
  69    buffers: RefCell<HashMap<BufferId, BufferState>>,
  70    // only used by consumers using `set_excerpts_for_buffer`
  71    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  72    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  73    diffs: HashMap<BufferId, DiffState>,
  74    // all_diff_hunks_expanded: bool,
  75    subscriptions: Topic,
  76    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  77    singleton: bool,
  78    history: History,
  79    title: Option<String>,
  80    capability: Capability,
  81    buffer_changed_since_sync: Rc<Cell<bool>>,
  82}
  83
  84#[derive(Clone, Debug, PartialEq, Eq)]
  85pub enum MultiOrSingleBufferOffsetRange {
  86    Single(Range<usize>),
  87    Multi(Range<usize>),
  88}
  89
  90#[derive(Clone, Debug, PartialEq, Eq)]
  91pub enum Event {
  92    ExcerptsAdded {
  93        buffer: Entity<Buffer>,
  94        predecessor: ExcerptId,
  95        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  96    },
  97    ExcerptsRemoved {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsExpanded {
 101        ids: Vec<ExcerptId>,
 102    },
 103    ExcerptsEdited {
 104        excerpt_ids: Vec<ExcerptId>,
 105        buffer_ids: Vec<BufferId>,
 106    },
 107    DiffHunksToggled,
 108    Edited {
 109        singleton_buffer_edited: bool,
 110        edited_buffer: Option<Entity<Buffer>>,
 111    },
 112    TransactionUndone {
 113        transaction_id: TransactionId,
 114    },
 115    Reloaded,
 116    ReloadNeeded,
 117
 118    LanguageChanged(BufferId),
 119    CapabilityChanged,
 120    Reparsed(BufferId),
 121    Saved,
 122    FileHandleChanged,
 123    Closed,
 124    Discarded,
 125    DirtyChanged,
 126    DiagnosticsUpdated,
 127    BufferDiffChanged,
 128}
 129
 130/// A diff hunk, representing a range of consequent lines in a multibuffer.
 131#[derive(Debug, Clone, PartialEq, Eq)]
 132pub struct MultiBufferDiffHunk {
 133    /// The row range in the multibuffer where this diff hunk appears.
 134    pub row_range: Range<MultiBufferRow>,
 135    /// The buffer ID that this hunk belongs to.
 136    pub buffer_id: BufferId,
 137    /// The range of the underlying buffer that this hunk corresponds to.
 138    pub buffer_range: Range<text::Anchor>,
 139    /// The excerpt that contains the diff hunk.
 140    pub excerpt_id: ExcerptId,
 141    /// The range within the buffer's diff base that this hunk corresponds to.
 142    pub diff_base_byte_range: Range<usize>,
 143    /// Whether or not this hunk also appears in the 'secondary diff'.
 144    pub secondary_status: DiffHunkSecondaryStatus,
 145}
 146
 147impl MultiBufferDiffHunk {
 148    pub fn status(&self) -> DiffHunkStatus {
 149        let kind = if self.buffer_range.start == self.buffer_range.end {
 150            DiffHunkStatusKind::Deleted
 151        } else if self.diff_base_byte_range.is_empty() {
 152            DiffHunkStatusKind::Added
 153        } else {
 154            DiffHunkStatusKind::Modified
 155        };
 156        DiffHunkStatus {
 157            kind,
 158            secondary: self.secondary_status,
 159        }
 160    }
 161
 162    pub fn is_created_file(&self) -> bool {
 163        self.diff_base_byte_range == (0..0)
 164            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 165    }
 166}
 167
 168#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 169pub struct PathKey {
 170    namespace: &'static str,
 171    path: Arc<Path>,
 172}
 173
 174impl PathKey {
 175    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 176        Self { namespace, path }
 177    }
 178
 179    pub fn path(&self) -> &Arc<Path> {
 180        &self.path
 181    }
 182}
 183
 184pub type MultiBufferPoint = Point;
 185type ExcerptOffset = TypedOffset<Excerpt>;
 186type ExcerptPoint = TypedPoint<Excerpt>;
 187
 188#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 189#[serde(transparent)]
 190pub struct MultiBufferRow(pub u32);
 191
 192impl MultiBufferRow {
 193    pub const MIN: Self = Self(0);
 194    pub const MAX: Self = Self(u32::MAX);
 195}
 196
 197impl std::ops::Add<usize> for MultiBufferRow {
 198    type Output = Self;
 199
 200    fn add(self, rhs: usize) -> Self::Output {
 201        MultiBufferRow(self.0 + rhs as u32)
 202    }
 203}
 204
 205#[derive(Clone)]
 206struct History {
 207    next_transaction_id: TransactionId,
 208    undo_stack: Vec<Transaction>,
 209    redo_stack: Vec<Transaction>,
 210    transaction_depth: usize,
 211    group_interval: Duration,
 212}
 213
 214#[derive(Clone)]
 215struct Transaction {
 216    id: TransactionId,
 217    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 218    first_edit_at: Instant,
 219    last_edit_at: Instant,
 220    suppress_grouping: bool,
 221}
 222
 223pub trait ToOffset: 'static + fmt::Debug {
 224    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 225}
 226
 227pub trait ToOffsetUtf16: 'static + fmt::Debug {
 228    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 229}
 230
 231pub trait ToPoint: 'static + fmt::Debug {
 232    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 233}
 234
 235pub trait ToPointUtf16: 'static + fmt::Debug {
 236    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 237}
 238
 239struct BufferState {
 240    buffer: Entity<Buffer>,
 241    last_version: clock::Global,
 242    last_non_text_state_update_count: usize,
 243    excerpts: Vec<Locator>,
 244    _subscriptions: [gpui::Subscription; 2],
 245}
 246
 247struct DiffState {
 248    diff: Entity<BufferDiff>,
 249    _subscription: gpui::Subscription,
 250}
 251
 252impl DiffState {
 253    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 254        DiffState {
 255            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 256                BufferDiffEvent::DiffChanged { changed_range } => {
 257                    if let Some(changed_range) = changed_range.clone() {
 258                        this.buffer_diff_changed(diff, changed_range, cx)
 259                    }
 260                    cx.emit(Event::BufferDiffChanged);
 261                }
 262                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 263                _ => {}
 264            }),
 265            diff,
 266        }
 267    }
 268}
 269
 270/// The contents of a [`MultiBuffer`] at a single point in time.
 271#[derive(Clone, Default)]
 272pub struct MultiBufferSnapshot {
 273    singleton: bool,
 274    excerpts: SumTree<Excerpt>,
 275    excerpt_ids: SumTree<ExcerptIdMapping>,
 276    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 277    diff_transforms: SumTree<DiffTransform>,
 278    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 279    trailing_excerpt_update_count: usize,
 280    all_diff_hunks_expanded: bool,
 281    non_text_state_update_count: usize,
 282    edit_count: usize,
 283    is_dirty: bool,
 284    has_deleted_file: bool,
 285    has_conflict: bool,
 286    show_headers: bool,
 287}
 288
 289#[derive(Debug, Clone)]
 290enum DiffTransform {
 291    BufferContent {
 292        summary: TextSummary,
 293        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 294    },
 295    DeletedHunk {
 296        summary: TextSummary,
 297        buffer_id: BufferId,
 298        hunk_info: DiffTransformHunkInfo,
 299        base_text_byte_range: Range<usize>,
 300        has_trailing_newline: bool,
 301    },
 302}
 303
 304#[derive(Clone, Copy, Debug)]
 305struct DiffTransformHunkInfo {
 306    excerpt_id: ExcerptId,
 307    hunk_start_anchor: text::Anchor,
 308    hunk_secondary_status: DiffHunkSecondaryStatus,
 309}
 310
 311impl Eq for DiffTransformHunkInfo {}
 312
 313impl PartialEq for DiffTransformHunkInfo {
 314    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 315        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 316    }
 317}
 318
 319impl std::hash::Hash for DiffTransformHunkInfo {
 320    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 321        self.excerpt_id.hash(state);
 322        self.hunk_start_anchor.hash(state);
 323    }
 324}
 325
 326#[derive(Clone)]
 327pub struct ExcerptInfo {
 328    pub id: ExcerptId,
 329    pub buffer: BufferSnapshot,
 330    pub buffer_id: BufferId,
 331    pub range: ExcerptRange<text::Anchor>,
 332    pub end_row: MultiBufferRow,
 333}
 334
 335impl std::fmt::Debug for ExcerptInfo {
 336    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 337        f.debug_struct(type_name::<Self>())
 338            .field("id", &self.id)
 339            .field("buffer_id", &self.buffer_id)
 340            .field("path", &self.buffer.file().map(|f| f.path()))
 341            .field("range", &self.range)
 342            .finish()
 343    }
 344}
 345
 346/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 347#[derive(Debug)]
 348pub struct ExcerptBoundary {
 349    pub prev: Option<ExcerptInfo>,
 350    pub next: ExcerptInfo,
 351    /// The row in the `MultiBuffer` where the boundary is located
 352    pub row: MultiBufferRow,
 353}
 354
 355impl ExcerptBoundary {
 356    pub fn starts_new_buffer(&self) -> bool {
 357        match (self.prev.as_ref(), &self.next) {
 358            (None, _) => true,
 359            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 360        }
 361    }
 362}
 363
 364#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 365pub struct ExpandInfo {
 366    pub direction: ExpandExcerptDirection,
 367    pub excerpt_id: ExcerptId,
 368}
 369
 370#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 371pub struct RowInfo {
 372    pub buffer_id: Option<BufferId>,
 373    pub buffer_row: Option<u32>,
 374    pub multibuffer_row: Option<MultiBufferRow>,
 375    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 376    pub expand_info: Option<ExpandInfo>,
 377}
 378
 379/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 380#[derive(Clone)]
 381struct Excerpt {
 382    /// The unique identifier for this excerpt
 383    id: ExcerptId,
 384    /// The location of the excerpt in the [`MultiBuffer`]
 385    locator: Locator,
 386    /// The buffer being excerpted
 387    buffer_id: BufferId,
 388    /// A snapshot of the buffer being excerpted
 389    buffer: BufferSnapshot,
 390    /// The range of the buffer to be shown in the excerpt
 391    range: ExcerptRange<text::Anchor>,
 392    /// The last row in the excerpted slice of the buffer
 393    max_buffer_row: BufferRow,
 394    /// A summary of the text in the excerpt
 395    text_summary: TextSummary,
 396    has_trailing_newline: bool,
 397}
 398
 399/// A public view into an `Excerpt` in a [`MultiBuffer`].
 400///
 401/// Contains methods for getting the [`Buffer`] of the excerpt,
 402/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 403#[derive(Clone)]
 404pub struct MultiBufferExcerpt<'a> {
 405    excerpt: &'a Excerpt,
 406    diff_transforms:
 407        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 408    offset: usize,
 409    excerpt_offset: ExcerptDimension<usize>,
 410    buffer_offset: usize,
 411}
 412
 413#[derive(Clone, Debug)]
 414struct ExcerptIdMapping {
 415    id: ExcerptId,
 416    locator: Locator,
 417}
 418
 419/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 420/// These ranges are relative to the buffer itself
 421#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 422pub struct ExcerptRange<T> {
 423    /// The full range of text to be shown in the excerpt.
 424    pub context: Range<T>,
 425    /// The primary range of text to be highlighted in the excerpt.
 426    /// In a multi-buffer search, this would be the text that matched the search
 427    pub primary: Range<T>,
 428}
 429
 430impl<T: Clone> ExcerptRange<T> {
 431    pub fn new(context: Range<T>) -> Self {
 432        Self {
 433            context: context.clone(),
 434            primary: context,
 435        }
 436    }
 437}
 438
 439#[derive(Clone, Debug, Default)]
 440pub struct ExcerptSummary {
 441    excerpt_id: ExcerptId,
 442    /// The location of the last [`Excerpt`] being summarized
 443    excerpt_locator: Locator,
 444    widest_line_number: u32,
 445    text: TextSummary,
 446}
 447
 448#[derive(Debug, Clone)]
 449pub struct DiffTransformSummary {
 450    input: TextSummary,
 451    output: TextSummary,
 452}
 453
 454#[derive(Clone)]
 455pub struct MultiBufferRows<'a> {
 456    point: Point,
 457    is_empty: bool,
 458    is_singleton: bool,
 459    cursor: MultiBufferCursor<'a, Point>,
 460}
 461
 462pub struct MultiBufferChunks<'a> {
 463    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 464    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 465    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 466    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 467    buffer_chunk: Option<Chunk<'a>>,
 468    range: Range<usize>,
 469    excerpt_offset_range: Range<ExcerptOffset>,
 470    excerpt_chunks: Option<ExcerptChunks<'a>>,
 471    language_aware: bool,
 472}
 473
 474pub struct ReversedMultiBufferChunks<'a> {
 475    cursor: MultiBufferCursor<'a, usize>,
 476    current_chunks: Option<rope::Chunks<'a>>,
 477    start: usize,
 478    offset: usize,
 479}
 480
 481pub struct MultiBufferBytes<'a> {
 482    range: Range<usize>,
 483    cursor: MultiBufferCursor<'a, usize>,
 484    excerpt_bytes: Option<text::Bytes<'a>>,
 485    has_trailing_newline: bool,
 486    chunk: &'a [u8],
 487}
 488
 489pub struct ReversedMultiBufferBytes<'a> {
 490    range: Range<usize>,
 491    chunks: ReversedMultiBufferChunks<'a>,
 492    chunk: &'a [u8],
 493}
 494
 495#[derive(Clone)]
 496struct MultiBufferCursor<'a, D: TextDimension> {
 497    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 498    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 499    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 500    cached_region: Option<MultiBufferRegion<'a, D>>,
 501}
 502
 503#[derive(Clone)]
 504struct MultiBufferRegion<'a, D: TextDimension> {
 505    buffer: &'a BufferSnapshot,
 506    is_main_buffer: bool,
 507    diff_hunk_status: Option<DiffHunkStatus>,
 508    excerpt: &'a Excerpt,
 509    buffer_range: Range<D>,
 510    range: Range<D>,
 511    has_trailing_newline: bool,
 512}
 513
 514struct ExcerptChunks<'a> {
 515    excerpt_id: ExcerptId,
 516    content_chunks: BufferChunks<'a>,
 517    footer_height: usize,
 518}
 519
 520#[derive(Debug)]
 521struct BufferEdit {
 522    range: Range<usize>,
 523    new_text: Arc<str>,
 524    is_insertion: bool,
 525    original_indent_column: Option<u32>,
 526    excerpt_id: ExcerptId,
 527}
 528
 529#[derive(Clone, Copy, Debug, PartialEq)]
 530enum DiffChangeKind {
 531    BufferEdited,
 532    DiffUpdated { base_changed: bool },
 533    ExpandOrCollapseHunks { expand: bool },
 534}
 535
 536#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 537pub enum ExpandExcerptDirection {
 538    Up,
 539    Down,
 540    UpAndDown,
 541}
 542
 543impl ExpandExcerptDirection {
 544    pub fn should_expand_up(&self) -> bool {
 545        match self {
 546            ExpandExcerptDirection::Up => true,
 547            ExpandExcerptDirection::Down => false,
 548            ExpandExcerptDirection::UpAndDown => true,
 549        }
 550    }
 551
 552    pub fn should_expand_down(&self) -> bool {
 553        match self {
 554            ExpandExcerptDirection::Up => false,
 555            ExpandExcerptDirection::Down => true,
 556            ExpandExcerptDirection::UpAndDown => true,
 557        }
 558    }
 559}
 560
 561#[derive(Clone, Debug, PartialEq)]
 562pub struct IndentGuide {
 563    pub buffer_id: BufferId,
 564    pub start_row: MultiBufferRow,
 565    pub end_row: MultiBufferRow,
 566    pub depth: u32,
 567    pub tab_size: u32,
 568    pub settings: IndentGuideSettings,
 569}
 570
 571impl IndentGuide {
 572    pub fn indent_level(&self) -> u32 {
 573        self.depth * self.tab_size
 574    }
 575}
 576
 577impl MultiBuffer {
 578    pub fn new(capability: Capability) -> Self {
 579        Self {
 580            snapshot: RefCell::new(MultiBufferSnapshot {
 581                show_headers: true,
 582                ..MultiBufferSnapshot::default()
 583            }),
 584            buffers: RefCell::default(),
 585            diffs: HashMap::default(),
 586            subscriptions: Topic::default(),
 587            singleton: false,
 588            capability,
 589            title: None,
 590            excerpts_by_path: Default::default(),
 591            paths_by_excerpt: Default::default(),
 592            buffer_changed_since_sync: Default::default(),
 593            history: History {
 594                next_transaction_id: clock::Lamport::default(),
 595                undo_stack: Vec::new(),
 596                redo_stack: Vec::new(),
 597                transaction_depth: 0,
 598                group_interval: Duration::from_millis(300),
 599            },
 600        }
 601    }
 602
 603    pub fn without_headers(capability: Capability) -> Self {
 604        Self {
 605            snapshot: Default::default(),
 606            buffers: Default::default(),
 607            excerpts_by_path: Default::default(),
 608            paths_by_excerpt: Default::default(),
 609            diffs: HashMap::default(),
 610            subscriptions: Default::default(),
 611            singleton: false,
 612            capability,
 613            buffer_changed_since_sync: Default::default(),
 614            history: History {
 615                next_transaction_id: Default::default(),
 616                undo_stack: Default::default(),
 617                redo_stack: Default::default(),
 618                transaction_depth: 0,
 619                group_interval: Duration::from_millis(300),
 620            },
 621            title: Default::default(),
 622        }
 623    }
 624
 625    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 626        let mut buffers = HashMap::default();
 627        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 628        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 629            buffer_state.buffer.update(new_cx, |buffer, _| {
 630                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 631            });
 632            buffers.insert(
 633                *buffer_id,
 634                BufferState {
 635                    buffer: buffer_state.buffer.clone(),
 636                    last_version: buffer_state.last_version.clone(),
 637                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 638                    excerpts: buffer_state.excerpts.clone(),
 639                    _subscriptions: [
 640                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 641                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 642                    ],
 643                },
 644            );
 645        }
 646        let mut diff_bases = HashMap::default();
 647        for (buffer_id, diff) in self.diffs.iter() {
 648            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 649        }
 650        Self {
 651            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 652            buffers: RefCell::new(buffers),
 653            excerpts_by_path: Default::default(),
 654            paths_by_excerpt: Default::default(),
 655            diffs: diff_bases,
 656            subscriptions: Default::default(),
 657            singleton: self.singleton,
 658            capability: self.capability,
 659            history: self.history.clone(),
 660            title: self.title.clone(),
 661            buffer_changed_since_sync,
 662        }
 663    }
 664
 665    pub fn with_title(mut self, title: String) -> Self {
 666        self.title = Some(title);
 667        self
 668    }
 669
 670    pub fn read_only(&self) -> bool {
 671        self.capability == Capability::ReadOnly
 672    }
 673
 674    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 675        let mut this = Self::new(buffer.read(cx).capability());
 676        this.singleton = true;
 677        this.push_excerpts(
 678            buffer,
 679            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 680            cx,
 681        );
 682        this.snapshot.borrow_mut().singleton = true;
 683        this
 684    }
 685
 686    /// Returns an up-to-date snapshot of the MultiBuffer.
 687    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 688        self.sync(cx);
 689        self.snapshot.borrow().clone()
 690    }
 691
 692    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 693        self.sync(cx);
 694        self.snapshot.borrow()
 695    }
 696
 697    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 698        if self.singleton {
 699            return Some(
 700                self.buffers
 701                    .borrow()
 702                    .values()
 703                    .next()
 704                    .unwrap()
 705                    .buffer
 706                    .clone(),
 707            );
 708        } else {
 709            None
 710        }
 711    }
 712
 713    pub fn is_singleton(&self) -> bool {
 714        self.singleton
 715    }
 716
 717    pub fn subscribe(&mut self) -> Subscription {
 718        self.subscriptions.subscribe()
 719    }
 720
 721    pub fn is_dirty(&self, cx: &App) -> bool {
 722        self.read(cx).is_dirty()
 723    }
 724
 725    pub fn has_deleted_file(&self, cx: &App) -> bool {
 726        self.read(cx).has_deleted_file()
 727    }
 728
 729    pub fn has_conflict(&self, cx: &App) -> bool {
 730        self.read(cx).has_conflict()
 731    }
 732
 733    // The `is_empty` signature doesn't match what clippy expects
 734    #[allow(clippy::len_without_is_empty)]
 735    pub fn len(&self, cx: &App) -> usize {
 736        self.read(cx).len()
 737    }
 738
 739    pub fn is_empty(&self) -> bool {
 740        self.buffers.borrow().is_empty()
 741    }
 742
 743    pub fn symbols_containing<T: ToOffset>(
 744        &self,
 745        offset: T,
 746        theme: Option<&SyntaxTheme>,
 747        cx: &App,
 748    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 749        self.read(cx).symbols_containing(offset, theme)
 750    }
 751
 752    pub fn edit<I, S, T>(
 753        &self,
 754        edits: I,
 755        autoindent_mode: Option<AutoindentMode>,
 756        cx: &mut Context<Self>,
 757    ) where
 758        I: IntoIterator<Item = (Range<S>, T)>,
 759        S: ToOffset,
 760        T: Into<Arc<str>>,
 761    {
 762        let snapshot = self.read(cx);
 763        let edits = edits
 764            .into_iter()
 765            .map(|(range, new_text)| {
 766                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 767                if range.start > range.end {
 768                    mem::swap(&mut range.start, &mut range.end);
 769                }
 770                (range, new_text.into())
 771            })
 772            .collect::<Vec<_>>();
 773
 774        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 775
 776        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 777        fn edit_internal(
 778            this: &MultiBuffer,
 779            snapshot: Ref<MultiBufferSnapshot>,
 780            edits: Vec<(Range<usize>, Arc<str>)>,
 781            mut autoindent_mode: Option<AutoindentMode>,
 782            cx: &mut Context<MultiBuffer>,
 783        ) {
 784            if this.read_only() || this.buffers.borrow().is_empty() {
 785                return;
 786            }
 787
 788            let original_indent_columns = match &mut autoindent_mode {
 789                Some(AutoindentMode::Block {
 790                    original_indent_columns,
 791                }) => mem::take(original_indent_columns),
 792                _ => Default::default(),
 793            };
 794
 795            let (buffer_edits, edited_excerpt_ids) =
 796                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 797            drop(snapshot);
 798
 799            let mut buffer_ids = Vec::new();
 800            for (buffer_id, mut edits) in buffer_edits {
 801                buffer_ids.push(buffer_id);
 802                edits.sort_by_key(|edit| edit.range.start);
 803                this.buffers.borrow()[&buffer_id]
 804                    .buffer
 805                    .update(cx, |buffer, cx| {
 806                        let mut edits = edits.into_iter().peekable();
 807                        let mut insertions = Vec::new();
 808                        let mut original_indent_columns = Vec::new();
 809                        let mut deletions = Vec::new();
 810                        let empty_str: Arc<str> = Arc::default();
 811                        while let Some(BufferEdit {
 812                            mut range,
 813                            mut new_text,
 814                            mut is_insertion,
 815                            original_indent_column,
 816                            excerpt_id,
 817                        }) = edits.next()
 818                        {
 819                            while let Some(BufferEdit {
 820                                range: next_range,
 821                                is_insertion: next_is_insertion,
 822                                new_text: next_new_text,
 823                                excerpt_id: next_excerpt_id,
 824                                ..
 825                            }) = edits.peek()
 826                            {
 827                                if range.end >= next_range.start {
 828                                    range.end = cmp::max(next_range.end, range.end);
 829                                    is_insertion |= *next_is_insertion;
 830                                    if excerpt_id == *next_excerpt_id {
 831                                        new_text = format!("{new_text}{next_new_text}").into();
 832                                    }
 833                                    edits.next();
 834                                } else {
 835                                    break;
 836                                }
 837                            }
 838
 839                            if is_insertion {
 840                                original_indent_columns.push(original_indent_column);
 841                                insertions.push((
 842                                    buffer.anchor_before(range.start)
 843                                        ..buffer.anchor_before(range.end),
 844                                    new_text.clone(),
 845                                ));
 846                            } else if !range.is_empty() {
 847                                deletions.push((
 848                                    buffer.anchor_before(range.start)
 849                                        ..buffer.anchor_before(range.end),
 850                                    empty_str.clone(),
 851                                ));
 852                            }
 853                        }
 854
 855                        let deletion_autoindent_mode =
 856                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 857                                Some(AutoindentMode::Block {
 858                                    original_indent_columns: Default::default(),
 859                                })
 860                            } else {
 861                                autoindent_mode.clone()
 862                            };
 863                        let insertion_autoindent_mode =
 864                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 865                                Some(AutoindentMode::Block {
 866                                    original_indent_columns,
 867                                })
 868                            } else {
 869                                autoindent_mode.clone()
 870                            };
 871
 872                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 873                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 874                    })
 875            }
 876
 877            cx.emit(Event::ExcerptsEdited {
 878                excerpt_ids: edited_excerpt_ids,
 879                buffer_ids,
 880            });
 881        }
 882    }
 883
 884    fn convert_edits_to_buffer_edits(
 885        &self,
 886        edits: Vec<(Range<usize>, Arc<str>)>,
 887        snapshot: &MultiBufferSnapshot,
 888        original_indent_columns: &[Option<u32>],
 889    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 890        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 891        let mut edited_excerpt_ids = Vec::new();
 892        let mut cursor = snapshot.cursor::<usize>();
 893        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 894            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 895
 896            cursor.seek(&range.start);
 897            let mut start_region = cursor.region().expect("start offset out of bounds");
 898            if !start_region.is_main_buffer {
 899                cursor.next();
 900                if let Some(region) = cursor.region() {
 901                    start_region = region;
 902                } else {
 903                    continue;
 904                }
 905            }
 906
 907            if range.end < start_region.range.start {
 908                continue;
 909            }
 910
 911            if range.end > start_region.range.end {
 912                cursor.seek_forward(&range.end);
 913            }
 914            let mut end_region = cursor.region().expect("end offset out of bounds");
 915            if !end_region.is_main_buffer {
 916                cursor.prev();
 917                if let Some(region) = cursor.region() {
 918                    end_region = region;
 919                } else {
 920                    continue;
 921                }
 922            }
 923
 924            if range.start > end_region.range.end {
 925                continue;
 926            }
 927
 928            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 929            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 930            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 931                .min(start_region.buffer_range.end);
 932            let buffer_end =
 933                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 934
 935            if start_region.excerpt.id == end_region.excerpt.id {
 936                if start_region.is_main_buffer {
 937                    edited_excerpt_ids.push(start_region.excerpt.id);
 938                    buffer_edits
 939                        .entry(start_region.buffer.remote_id())
 940                        .or_default()
 941                        .push(BufferEdit {
 942                            range: buffer_start..buffer_end,
 943                            new_text,
 944                            is_insertion: true,
 945                            original_indent_column,
 946                            excerpt_id: start_region.excerpt.id,
 947                        });
 948                }
 949            } else {
 950                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 951                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 952                if start_region.is_main_buffer {
 953                    edited_excerpt_ids.push(start_region.excerpt.id);
 954                    buffer_edits
 955                        .entry(start_region.buffer.remote_id())
 956                        .or_default()
 957                        .push(BufferEdit {
 958                            range: start_excerpt_range,
 959                            new_text: new_text.clone(),
 960                            is_insertion: true,
 961                            original_indent_column,
 962                            excerpt_id: start_region.excerpt.id,
 963                        });
 964                }
 965                if end_region.is_main_buffer {
 966                    edited_excerpt_ids.push(end_region.excerpt.id);
 967                    buffer_edits
 968                        .entry(end_region.buffer.remote_id())
 969                        .or_default()
 970                        .push(BufferEdit {
 971                            range: end_excerpt_range,
 972                            new_text: new_text.clone(),
 973                            is_insertion: false,
 974                            original_indent_column,
 975                            excerpt_id: end_region.excerpt.id,
 976                        });
 977                }
 978
 979                cursor.seek(&range.start);
 980                cursor.next_excerpt();
 981                while let Some(region) = cursor.region() {
 982                    if region.excerpt.id == end_region.excerpt.id {
 983                        break;
 984                    }
 985                    if region.is_main_buffer {
 986                        edited_excerpt_ids.push(region.excerpt.id);
 987                        buffer_edits
 988                            .entry(region.buffer.remote_id())
 989                            .or_default()
 990                            .push(BufferEdit {
 991                                range: region.buffer_range,
 992                                new_text: new_text.clone(),
 993                                is_insertion: false,
 994                                original_indent_column,
 995                                excerpt_id: region.excerpt.id,
 996                            });
 997                    }
 998                    cursor.next_excerpt();
 999                }
1000            }
1001        }
1002        (buffer_edits, edited_excerpt_ids)
1003    }
1004
1005    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1006    where
1007        I: IntoIterator<Item = Range<S>>,
1008        S: ToOffset,
1009    {
1010        let snapshot = self.read(cx);
1011        let empty = Arc::<str>::from("");
1012        let edits = ranges
1013            .into_iter()
1014            .map(|range| {
1015                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1016                if range.start > range.end {
1017                    mem::swap(&mut range.start, &mut range.end);
1018                }
1019                (range, empty.clone())
1020            })
1021            .collect::<Vec<_>>();
1022
1023        return autoindent_ranges_internal(self, snapshot, edits, cx);
1024
1025        fn autoindent_ranges_internal(
1026            this: &MultiBuffer,
1027            snapshot: Ref<MultiBufferSnapshot>,
1028            edits: Vec<(Range<usize>, Arc<str>)>,
1029            cx: &mut Context<MultiBuffer>,
1030        ) {
1031            if this.read_only() || this.buffers.borrow().is_empty() {
1032                return;
1033            }
1034
1035            let (buffer_edits, edited_excerpt_ids) =
1036                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1037            drop(snapshot);
1038
1039            let mut buffer_ids = Vec::new();
1040            for (buffer_id, mut edits) in buffer_edits {
1041                buffer_ids.push(buffer_id);
1042                edits.sort_unstable_by_key(|edit| edit.range.start);
1043
1044                let mut ranges: Vec<Range<usize>> = Vec::new();
1045                for edit in edits {
1046                    if let Some(last_range) = ranges.last_mut() {
1047                        if edit.range.start <= last_range.end {
1048                            last_range.end = last_range.end.max(edit.range.end);
1049                            continue;
1050                        }
1051                    }
1052                    ranges.push(edit.range);
1053                }
1054
1055                this.buffers.borrow()[&buffer_id]
1056                    .buffer
1057                    .update(cx, |buffer, cx| {
1058                        buffer.autoindent_ranges(ranges, cx);
1059                    })
1060            }
1061
1062            cx.emit(Event::ExcerptsEdited {
1063                excerpt_ids: edited_excerpt_ids,
1064                buffer_ids,
1065            });
1066        }
1067    }
1068
1069    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1070    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1071    // Panics if the given position is invalid.
1072    pub fn insert_empty_line(
1073        &mut self,
1074        position: impl ToPoint,
1075        space_above: bool,
1076        space_below: bool,
1077        cx: &mut Context<Self>,
1078    ) -> Point {
1079        let multibuffer_point = position.to_point(&self.read(cx));
1080        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1081        self.start_transaction(cx);
1082        let empty_line_start = buffer.update(cx, |buffer, cx| {
1083            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1084        });
1085        self.end_transaction(cx);
1086        multibuffer_point + (empty_line_start - buffer_point)
1087    }
1088
1089    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1090        self.start_transaction_at(Instant::now(), cx)
1091    }
1092
1093    pub fn start_transaction_at(
1094        &mut self,
1095        now: Instant,
1096        cx: &mut Context<Self>,
1097    ) -> Option<TransactionId> {
1098        if let Some(buffer) = self.as_singleton() {
1099            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1100        }
1101
1102        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1103            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1104        }
1105        self.history.start_transaction(now)
1106    }
1107
1108    pub fn last_transaction_id(&self) -> Option<TransactionId> {
1109        let last_transaction = self.history.undo_stack.last()?;
1110        return Some(last_transaction.id);
1111    }
1112
1113    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1114        self.end_transaction_at(Instant::now(), cx)
1115    }
1116
1117    pub fn end_transaction_at(
1118        &mut self,
1119        now: Instant,
1120        cx: &mut Context<Self>,
1121    ) -> Option<TransactionId> {
1122        if let Some(buffer) = self.as_singleton() {
1123            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1124        }
1125
1126        let mut buffer_transactions = HashMap::default();
1127        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1128            if let Some(transaction_id) =
1129                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1130            {
1131                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1132            }
1133        }
1134
1135        if self.history.end_transaction(now, buffer_transactions) {
1136            let transaction_id = self.history.group().unwrap();
1137            Some(transaction_id)
1138        } else {
1139            None
1140        }
1141    }
1142
1143    pub fn edited_ranges_for_transaction<D>(
1144        &self,
1145        transaction_id: TransactionId,
1146        cx: &App,
1147    ) -> Vec<Range<D>>
1148    where
1149        D: TextDimension + Ord + Sub<D, Output = D>,
1150    {
1151        let Some(transaction) = self.history.transaction(transaction_id) else {
1152            return Vec::new();
1153        };
1154
1155        let mut ranges = Vec::new();
1156        let snapshot = self.read(cx);
1157        let buffers = self.buffers.borrow();
1158        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1159
1160        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1161            let Some(buffer_state) = buffers.get(buffer_id) else {
1162                continue;
1163            };
1164
1165            let buffer = buffer_state.buffer.read(cx);
1166            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1167                for excerpt_id in &buffer_state.excerpts {
1168                    cursor.seek(excerpt_id, Bias::Left, &());
1169                    if let Some(excerpt) = cursor.item() {
1170                        if excerpt.locator == *excerpt_id {
1171                            let excerpt_buffer_start =
1172                                excerpt.range.context.start.summary::<D>(buffer);
1173                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1174                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1175                            if excerpt_range.contains(&range.start)
1176                                && excerpt_range.contains(&range.end)
1177                            {
1178                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1179
1180                                let mut start = excerpt_start;
1181                                start.add_assign(&(range.start - excerpt_buffer_start));
1182                                let mut end = excerpt_start;
1183                                end.add_assign(&(range.end - excerpt_buffer_start));
1184
1185                                ranges.push(start..end);
1186                                break;
1187                            }
1188                        }
1189                    }
1190                }
1191            }
1192        }
1193
1194        ranges.sort_by_key(|range| range.start);
1195        ranges
1196    }
1197
1198    pub fn merge_transactions(
1199        &mut self,
1200        transaction: TransactionId,
1201        destination: TransactionId,
1202        cx: &mut Context<Self>,
1203    ) {
1204        if let Some(buffer) = self.as_singleton() {
1205            buffer.update(cx, |buffer, _| {
1206                buffer.merge_transactions(transaction, destination)
1207            });
1208        } else if let Some(transaction) = self.history.forget(transaction) {
1209            if let Some(destination) = self.history.transaction_mut(destination) {
1210                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1211                    if let Some(destination_buffer_transaction_id) =
1212                        destination.buffer_transactions.get(&buffer_id)
1213                    {
1214                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1215                            state.buffer.update(cx, |buffer, _| {
1216                                buffer.merge_transactions(
1217                                    buffer_transaction_id,
1218                                    *destination_buffer_transaction_id,
1219                                )
1220                            });
1221                        }
1222                    } else {
1223                        destination
1224                            .buffer_transactions
1225                            .insert(buffer_id, buffer_transaction_id);
1226                    }
1227                }
1228            }
1229        }
1230    }
1231
1232    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1233        self.history.finalize_last_transaction();
1234        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1235            buffer.update(cx, |buffer, _| {
1236                buffer.finalize_last_transaction();
1237            });
1238        }
1239    }
1240
1241    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1242    where
1243        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1244    {
1245        self.history
1246            .push_transaction(buffer_transactions, Instant::now(), cx);
1247        self.history.finalize_last_transaction();
1248    }
1249
1250    pub fn group_until_transaction(
1251        &mut self,
1252        transaction_id: TransactionId,
1253        cx: &mut Context<Self>,
1254    ) {
1255        if let Some(buffer) = self.as_singleton() {
1256            buffer.update(cx, |buffer, _| {
1257                buffer.group_until_transaction(transaction_id)
1258            });
1259        } else {
1260            self.history.group_until(transaction_id);
1261        }
1262    }
1263
1264    pub fn set_active_selections(
1265        &self,
1266        selections: &[Selection<Anchor>],
1267        line_mode: bool,
1268        cursor_shape: CursorShape,
1269        cx: &mut Context<Self>,
1270    ) {
1271        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1272            Default::default();
1273        let snapshot = self.read(cx);
1274        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1275        for selection in selections {
1276            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1277            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1278
1279            cursor.seek(&Some(start_locator), Bias::Left, &());
1280            while let Some(excerpt) = cursor.item() {
1281                if excerpt.locator > *end_locator {
1282                    break;
1283                }
1284
1285                let mut start = excerpt.range.context.start;
1286                let mut end = excerpt.range.context.end;
1287                if excerpt.id == selection.start.excerpt_id {
1288                    start = selection.start.text_anchor;
1289                }
1290                if excerpt.id == selection.end.excerpt_id {
1291                    end = selection.end.text_anchor;
1292                }
1293                selections_by_buffer
1294                    .entry(excerpt.buffer_id)
1295                    .or_default()
1296                    .push(Selection {
1297                        id: selection.id,
1298                        start,
1299                        end,
1300                        reversed: selection.reversed,
1301                        goal: selection.goal,
1302                    });
1303
1304                cursor.next(&());
1305            }
1306        }
1307
1308        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1309            if !selections_by_buffer.contains_key(buffer_id) {
1310                buffer_state
1311                    .buffer
1312                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1313            }
1314        }
1315
1316        for (buffer_id, mut selections) in selections_by_buffer {
1317            self.buffers.borrow()[&buffer_id]
1318                .buffer
1319                .update(cx, |buffer, cx| {
1320                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1321                    let mut selections = selections.into_iter().peekable();
1322                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1323                        let mut selection = selections.next()?;
1324                        while let Some(next_selection) = selections.peek() {
1325                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1326                                let next_selection = selections.next().unwrap();
1327                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1328                                    selection.end = next_selection.end;
1329                                }
1330                            } else {
1331                                break;
1332                            }
1333                        }
1334                        Some(selection)
1335                    }));
1336                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1337                });
1338        }
1339    }
1340
1341    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1342        for buffer in self.buffers.borrow().values() {
1343            buffer
1344                .buffer
1345                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1346        }
1347    }
1348
1349    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1350        let mut transaction_id = None;
1351        if let Some(buffer) = self.as_singleton() {
1352            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1353        } else {
1354            while let Some(transaction) = self.history.pop_undo() {
1355                let mut undone = 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                        undone |= buffer.update(cx, |buffer, cx| {
1359                            let undo_to = *buffer_transaction_id;
1360                            if let Some(entry) = buffer.peek_undo_stack() {
1361                                *buffer_transaction_id = entry.transaction_id();
1362                            }
1363                            buffer.undo_to_transaction(undo_to, cx)
1364                        });
1365                    }
1366                }
1367
1368                if undone {
1369                    transaction_id = Some(transaction.id);
1370                    break;
1371                }
1372            }
1373        }
1374
1375        if let Some(transaction_id) = transaction_id {
1376            cx.emit(Event::TransactionUndone { transaction_id });
1377        }
1378
1379        transaction_id
1380    }
1381
1382    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1383        if let Some(buffer) = self.as_singleton() {
1384            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1385        }
1386
1387        while let Some(transaction) = self.history.pop_redo() {
1388            let mut redone = false;
1389            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1390                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1391                    redone |= buffer.update(cx, |buffer, cx| {
1392                        let redo_to = *buffer_transaction_id;
1393                        if let Some(entry) = buffer.peek_redo_stack() {
1394                            *buffer_transaction_id = entry.transaction_id();
1395                        }
1396                        buffer.redo_to_transaction(redo_to, cx)
1397                    });
1398                }
1399            }
1400
1401            if redone {
1402                return Some(transaction.id);
1403            }
1404        }
1405
1406        None
1407    }
1408
1409    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1410        if let Some(buffer) = self.as_singleton() {
1411            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1412        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1413            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1414                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1415                    buffer.update(cx, |buffer, cx| {
1416                        buffer.undo_transaction(*transaction_id, cx)
1417                    });
1418                }
1419            }
1420        }
1421    }
1422
1423    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1424        if let Some(buffer) = self.as_singleton() {
1425            buffer.update(cx, |buffer, _| {
1426                buffer.forget_transaction(transaction_id);
1427            });
1428        } else if let Some(transaction) = self.history.forget(transaction_id) {
1429            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1430                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1431                    state.buffer.update(cx, |buffer, _| {
1432                        buffer.forget_transaction(buffer_transaction_id);
1433                    });
1434                }
1435            }
1436        }
1437    }
1438
1439    pub fn push_excerpts<O>(
1440        &mut self,
1441        buffer: Entity<Buffer>,
1442        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1443        cx: &mut Context<Self>,
1444    ) -> Vec<ExcerptId>
1445    where
1446        O: text::ToOffset,
1447    {
1448        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1449    }
1450
1451    pub fn push_excerpts_with_context_lines<O>(
1452        &mut self,
1453        buffer: Entity<Buffer>,
1454        ranges: Vec<Range<O>>,
1455        context_line_count: u32,
1456        cx: &mut Context<Self>,
1457    ) -> Vec<Range<Anchor>>
1458    where
1459        O: text::ToPoint + text::ToOffset,
1460    {
1461        let buffer_id = buffer.read(cx).remote_id();
1462        let buffer_snapshot = buffer.read(cx).snapshot();
1463        let (excerpt_ranges, range_counts) =
1464            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1465
1466        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1467
1468        let mut anchor_ranges = Vec::new();
1469        let mut ranges = ranges.into_iter();
1470        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1471            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1472                let start = Anchor {
1473                    buffer_id: Some(buffer_id),
1474                    excerpt_id,
1475                    text_anchor: buffer_snapshot.anchor_after(range.start),
1476                    diff_base_anchor: None,
1477                };
1478                let end = Anchor {
1479                    buffer_id: Some(buffer_id),
1480                    excerpt_id,
1481                    text_anchor: buffer_snapshot.anchor_after(range.end),
1482                    diff_base_anchor: None,
1483                };
1484                start..end
1485            }))
1486        }
1487        anchor_ranges
1488    }
1489
1490    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1491        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1492        let snapshot = self.snapshot(cx);
1493        let excerpt = snapshot.excerpt(*excerpt_id)?;
1494        Some(Anchor::in_buffer(
1495            *excerpt_id,
1496            excerpt.buffer_id,
1497            excerpt.range.context.start,
1498        ))
1499    }
1500
1501    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1502        self.excerpts_by_path.keys()
1503    }
1504
1505    fn expand_excerpts_with_paths(
1506        &mut self,
1507        ids: impl IntoIterator<Item = ExcerptId>,
1508        line_count: u32,
1509        direction: ExpandExcerptDirection,
1510        cx: &mut Context<Self>,
1511    ) {
1512        let grouped = ids
1513            .into_iter()
1514            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1515            .into_iter()
1516            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1517            .collect::<Vec<_>>();
1518        let snapshot = self.snapshot(cx);
1519
1520        for (path, ids) in grouped.into_iter() {
1521            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1522                continue;
1523            };
1524
1525            let ids_to_expand = HashSet::from_iter(ids);
1526            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1527                let excerpt = snapshot.excerpt(*excerpt_id)?;
1528
1529                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1530                if ids_to_expand.contains(excerpt_id) {
1531                    match direction {
1532                        ExpandExcerptDirection::Up => {
1533                            context.start.row = context.start.row.saturating_sub(line_count);
1534                            context.start.column = 0;
1535                        }
1536                        ExpandExcerptDirection::Down => {
1537                            context.end.row =
1538                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1539                            context.end.column = excerpt.buffer.line_len(context.end.row);
1540                        }
1541                        ExpandExcerptDirection::UpAndDown => {
1542                            context.start.row = context.start.row.saturating_sub(line_count);
1543                            context.start.column = 0;
1544                            context.end.row =
1545                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1546                            context.end.column = excerpt.buffer.line_len(context.end.row);
1547                        }
1548                    }
1549                }
1550
1551                Some(ExcerptRange {
1552                    context,
1553                    primary: excerpt.range.primary.to_point(&excerpt.buffer),
1554                })
1555            });
1556            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1557            for range in expanded_ranges {
1558                if let Some(last_range) = merged_ranges.last_mut() {
1559                    if last_range.context.end >= range.context.start {
1560                        last_range.context.end = range.context.end;
1561                        continue;
1562                    }
1563                }
1564                merged_ranges.push(range)
1565            }
1566            let Some(excerpt_id) = excerpt_ids.first() else {
1567                continue;
1568            };
1569            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1570                continue;
1571            };
1572
1573            let Some(buffer) = self
1574                .buffers
1575                .borrow()
1576                .get(buffer_id)
1577                .map(|b| b.buffer.clone())
1578            else {
1579                continue;
1580            };
1581
1582            let buffer_snapshot = buffer.read(cx).snapshot();
1583            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1584        }
1585    }
1586
1587    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1588    pub fn set_excerpts_for_path(
1589        &mut self,
1590        path: PathKey,
1591        buffer: Entity<Buffer>,
1592        ranges: Vec<Range<Point>>,
1593        context_line_count: u32,
1594        cx: &mut Context<Self>,
1595    ) -> bool {
1596        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1597
1598        let excerpt_ranges = ranges.into_iter().map(|range| {
1599            let start = range
1600                .start
1601                .saturating_sub(Point::new(context_line_count, 0));
1602            let end_row = (range.end.row + 2).min(buffer_snapshot.max_point().row);
1603            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
1604            ExcerptRange {
1605                context: start..end,
1606                primary: range,
1607            }
1608        });
1609
1610        let (_, is_new) =
1611            self.set_excerpt_ranges_for_path(path, buffer, excerpt_ranges.collect(), cx);
1612        is_new
1613    }
1614
1615    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1616    pub fn set_excerpt_ranges_for_path(
1617        &mut self,
1618        path: PathKey,
1619        buffer: Entity<Buffer>,
1620        ranges: Vec<ExcerptRange<Point>>,
1621        cx: &mut Context<Self>,
1622    ) -> (Vec<Range<Anchor>>, bool) {
1623        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1624
1625        let (new, counts) = self.merge_excerpt_ranges(&ranges);
1626        let (excerpt_ids, added_a_new_excerpt) =
1627            self.update_path_excerpts(path, buffer, &buffer_snapshot, new, cx);
1628
1629        let mut result = Vec::new();
1630        let mut ranges = ranges.into_iter();
1631        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(counts.into_iter()) {
1632            for range in ranges.by_ref().take(range_count) {
1633                let range = Anchor::range_in_buffer(
1634                    excerpt_id,
1635                    buffer_snapshot.remote_id(),
1636                    buffer_snapshot.anchor_before(&range.primary.start)
1637                        ..buffer_snapshot.anchor_after(&range.primary.end),
1638                );
1639                result.push(range)
1640            }
1641        }
1642        (result, added_a_new_excerpt)
1643    }
1644
1645    fn merge_excerpt_ranges(
1646        &self,
1647        expanded_ranges: &Vec<ExcerptRange<Point>>,
1648    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1649        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1650        let mut counts: Vec<usize> = Vec::new();
1651        for range in expanded_ranges {
1652            if let Some(last_range) = merged_ranges.last_mut() {
1653                if last_range.context.end >= range.context.start {
1654                    last_range.context.end = range.context.end;
1655                    *counts.last_mut().unwrap() += 1;
1656                    continue;
1657                }
1658            }
1659            merged_ranges.push(range.clone());
1660            counts.push(1);
1661        }
1662        return (merged_ranges, counts);
1663    }
1664
1665    fn update_path_excerpts(
1666        &mut self,
1667        path: PathKey,
1668        buffer: Entity<Buffer>,
1669        buffer_snapshot: &BufferSnapshot,
1670        new: Vec<ExcerptRange<Point>>,
1671        cx: &mut Context<Self>,
1672    ) -> (Vec<ExcerptId>, bool) {
1673        let mut insert_after = self
1674            .excerpts_by_path
1675            .range(..path.clone())
1676            .next_back()
1677            .map(|(_, value)| *value.last().unwrap())
1678            .unwrap_or(ExcerptId::min());
1679
1680        let existing = self
1681            .excerpts_by_path
1682            .get(&path)
1683            .cloned()
1684            .unwrap_or_default();
1685
1686        let mut new_iter = new.into_iter().peekable();
1687        let mut existing_iter = existing.into_iter().peekable();
1688
1689        let mut excerpt_ids = Vec::new();
1690        let mut to_remove = Vec::new();
1691        let mut to_insert: Vec<(ExcerptId, ExcerptRange<Point>)> = Vec::new();
1692        let mut added_a_new_excerpt = false;
1693        let snapshot = self.snapshot(cx);
1694
1695        let mut next_excerpt_id =
1696            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1697                last_entry.id.0 + 1
1698            } else {
1699                1
1700            };
1701
1702        let mut next_excerpt_id = move || ExcerptId(post_inc(&mut next_excerpt_id));
1703
1704        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1705        excerpts_cursor.next(&());
1706
1707        loop {
1708            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1709                (Some(new), Some(existing)) => (new, existing),
1710                (None, None) => break,
1711                (None, Some(_)) => {
1712                    let existing_id = existing_iter.next().unwrap();
1713                    let locator = snapshot.excerpt_locator_for_id(existing_id);
1714                    let existing_excerpt = excerpts_cursor.item().unwrap();
1715                    excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1716                    let existing_end = existing_excerpt
1717                        .range
1718                        .context
1719                        .end
1720                        .to_point(&buffer_snapshot);
1721                    if let Some((new_id, last)) = to_insert.last() {
1722                        if existing_end <= last.context.end {
1723                            self.snapshot
1724                                .borrow_mut()
1725                                .replaced_excerpts
1726                                .insert(existing_id, *new_id);
1727                        }
1728                    }
1729                    to_remove.push(existing_id);
1730                    continue;
1731                }
1732                (Some(_), None) => {
1733                    added_a_new_excerpt = true;
1734                    to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1735                    continue;
1736                }
1737            };
1738            let locator = snapshot.excerpt_locator_for_id(*existing);
1739            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1740            let Some(existing_excerpt) = excerpts_cursor.item() else {
1741                to_remove.push(existing_iter.next().unwrap());
1742                to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1743                continue;
1744            };
1745            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1746                to_remove.push(existing_iter.next().unwrap());
1747                to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1748                continue;
1749            }
1750
1751            let existing_start = existing_excerpt
1752                .range
1753                .context
1754                .start
1755                .to_point(&buffer_snapshot);
1756            let existing_end = existing_excerpt
1757                .range
1758                .context
1759                .end
1760                .to_point(&buffer_snapshot);
1761
1762            if existing_end < new.context.start {
1763                let existing_id = existing_iter.next().unwrap();
1764                if let Some((new_id, last)) = to_insert.last() {
1765                    if existing_end <= last.context.end {
1766                        self.snapshot
1767                            .borrow_mut()
1768                            .replaced_excerpts
1769                            .insert(existing_id, *new_id);
1770                    }
1771                }
1772                to_remove.push(existing_id);
1773                continue;
1774            } else if existing_start > new.context.end {
1775                to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1776                continue;
1777            }
1778
1779            if existing_start == new.context.start && existing_end == new.context.end {
1780                excerpt_ids.extend(to_insert.iter().map(|(id, _)| id));
1781                self.insert_excerpts_with_ids_after(
1782                    insert_after,
1783                    buffer.clone(),
1784                    mem::take(&mut to_insert),
1785                    cx,
1786                );
1787                insert_after = existing_iter.next().unwrap();
1788                excerpt_ids.push(insert_after);
1789                new_iter.next();
1790            } else {
1791                let existing_id = existing_iter.next().unwrap();
1792                let new_id = next_excerpt_id();
1793                self.snapshot
1794                    .borrow_mut()
1795                    .replaced_excerpts
1796                    .insert(existing_id, new_id);
1797                to_remove.push(existing_id);
1798                let mut range = new_iter.next().unwrap();
1799                range.context.start = range.context.start.min(existing_start);
1800                range.context.end = range.context.end.max(existing_end);
1801                to_insert.push((new_id, range));
1802            }
1803        }
1804
1805        excerpt_ids.extend(to_insert.iter().map(|(id, _)| id));
1806        self.insert_excerpts_with_ids_after(insert_after, buffer, to_insert, cx);
1807        self.remove_excerpts(to_remove, cx);
1808        if excerpt_ids.is_empty() {
1809            self.excerpts_by_path.remove(&path);
1810        } else {
1811            for excerpt_id in &excerpt_ids {
1812                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1813            }
1814            self.excerpts_by_path.insert(path, excerpt_ids.clone());
1815        }
1816
1817        (excerpt_ids, added_a_new_excerpt)
1818    }
1819
1820    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1821        self.excerpts_by_path.keys().cloned()
1822    }
1823
1824    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1825        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1826            self.remove_excerpts(to_remove, cx)
1827        }
1828    }
1829
1830    pub fn push_multiple_excerpts_with_context_lines(
1831        &self,
1832        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1833        context_line_count: u32,
1834        cx: &mut Context<Self>,
1835    ) -> Task<Vec<Range<Anchor>>> {
1836        use futures::StreamExt;
1837
1838        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1839
1840        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1841
1842        for (buffer, ranges) in buffers_with_ranges {
1843            let (buffer_id, buffer_snapshot) =
1844                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1845
1846            buffer_ids.push(buffer_id);
1847
1848            cx.background_spawn({
1849                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1850
1851                async move {
1852                    let (excerpt_ranges, counts) =
1853                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1854                    excerpt_ranges_tx
1855                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1856                        .await
1857                        .ok();
1858                }
1859            })
1860            .detach()
1861        }
1862
1863        cx.spawn(async move |this, cx| {
1864            let mut results_by_buffer_id = HashMap::default();
1865            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1866                excerpt_ranges_rx.next().await
1867            {
1868                results_by_buffer_id
1869                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1870            }
1871
1872            let mut multi_buffer_ranges = Vec::default();
1873            'outer: for buffer_id in buffer_ids {
1874                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1875                    results_by_buffer_id.remove(&buffer_id)
1876                else {
1877                    continue;
1878                };
1879
1880                let mut ranges = ranges.into_iter();
1881                let mut range_counts = range_counts.into_iter();
1882                for excerpt_ranges in excerpt_ranges.chunks(100) {
1883                    let excerpt_ids = match this.update(cx, |this, cx| {
1884                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1885                    }) {
1886                        Ok(excerpt_ids) => excerpt_ids,
1887                        Err(_) => continue 'outer,
1888                    };
1889
1890                    for (excerpt_id, range_count) in
1891                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1892                    {
1893                        for range in ranges.by_ref().take(range_count) {
1894                            let start = Anchor {
1895                                buffer_id: Some(buffer_id),
1896                                excerpt_id,
1897                                text_anchor: range.start,
1898                                diff_base_anchor: None,
1899                            };
1900                            let end = Anchor {
1901                                buffer_id: Some(buffer_id),
1902                                excerpt_id,
1903                                text_anchor: range.end,
1904                                diff_base_anchor: None,
1905                            };
1906                            multi_buffer_ranges.push(start..end);
1907                        }
1908                    }
1909                }
1910            }
1911
1912            multi_buffer_ranges
1913        })
1914    }
1915
1916    pub fn insert_excerpts_after<O>(
1917        &mut self,
1918        prev_excerpt_id: ExcerptId,
1919        buffer: Entity<Buffer>,
1920        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1921        cx: &mut Context<Self>,
1922    ) -> Vec<ExcerptId>
1923    where
1924        O: text::ToOffset,
1925    {
1926        let mut ids = Vec::new();
1927        let mut next_excerpt_id =
1928            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1929                last_entry.id.0 + 1
1930            } else {
1931                1
1932            };
1933        self.insert_excerpts_with_ids_after(
1934            prev_excerpt_id,
1935            buffer,
1936            ranges.into_iter().map(|range| {
1937                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1938                ids.push(id);
1939                (id, range)
1940            }),
1941            cx,
1942        );
1943        ids
1944    }
1945
1946    pub fn insert_excerpts_with_ids_after<O>(
1947        &mut self,
1948        prev_excerpt_id: ExcerptId,
1949        buffer: Entity<Buffer>,
1950        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1951        cx: &mut Context<Self>,
1952    ) where
1953        O: text::ToOffset,
1954    {
1955        assert_eq!(self.history.transaction_depth, 0);
1956        let mut ranges = ranges.into_iter().peekable();
1957        if ranges.peek().is_none() {
1958            return Default::default();
1959        }
1960
1961        self.sync(cx);
1962
1963        let buffer_snapshot = buffer.read(cx).snapshot();
1964        let buffer_id = buffer_snapshot.remote_id();
1965
1966        let mut buffers = self.buffers.borrow_mut();
1967        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1968            self.buffer_changed_since_sync.replace(true);
1969            buffer.update(cx, |buffer, _| {
1970                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1971            });
1972            BufferState {
1973                last_version: buffer_snapshot.version().clone(),
1974                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1975                excerpts: Default::default(),
1976                _subscriptions: [
1977                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1978                    cx.subscribe(&buffer, Self::on_buffer_event),
1979                ],
1980                buffer: buffer.clone(),
1981            }
1982        });
1983
1984        let mut snapshot = self.snapshot.borrow_mut();
1985
1986        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1987        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1988        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1989        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1990        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1991
1992        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1993        new_excerpts.update_last(
1994            |excerpt| {
1995                excerpt.has_trailing_newline = true;
1996            },
1997            &(),
1998        );
1999
2000        let next_locator = if let Some(excerpt) = cursor.item() {
2001            excerpt.locator.clone()
2002        } else {
2003            Locator::max()
2004        };
2005
2006        let mut excerpts = Vec::new();
2007        while let Some((id, range)) = ranges.next() {
2008            let locator = Locator::between(&prev_locator, &next_locator);
2009            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
2010                buffer_state.excerpts.insert(ix, locator.clone());
2011            }
2012            let range = ExcerptRange {
2013                context: buffer_snapshot.anchor_before(&range.context.start)
2014                    ..buffer_snapshot.anchor_after(&range.context.end),
2015                primary: buffer_snapshot.anchor_before(&range.primary.start)
2016                    ..buffer_snapshot.anchor_after(&range.primary.end),
2017            };
2018            excerpts.push((id, range.clone()));
2019            let excerpt = Excerpt::new(
2020                id,
2021                locator.clone(),
2022                buffer_id,
2023                buffer_snapshot.clone(),
2024                range,
2025                ranges.peek().is_some() || cursor.item().is_some(),
2026            );
2027            new_excerpts.push(excerpt, &());
2028            prev_locator = locator.clone();
2029
2030            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
2031                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
2032            }
2033            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
2034        }
2035
2036        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
2037
2038        let suffix = cursor.suffix(&());
2039        let changed_trailing_excerpt = suffix.is_empty();
2040        new_excerpts.append(suffix, &());
2041        drop(cursor);
2042        snapshot.excerpts = new_excerpts;
2043        snapshot.excerpt_ids = new_excerpt_ids;
2044        if changed_trailing_excerpt {
2045            snapshot.trailing_excerpt_update_count += 1;
2046        }
2047
2048        self.sync_diff_transforms(
2049            &mut snapshot,
2050            vec![Edit {
2051                old: edit_start..edit_start,
2052                new: edit_start..edit_end,
2053            }],
2054            DiffChangeKind::BufferEdited,
2055        );
2056        cx.emit(Event::Edited {
2057            singleton_buffer_edited: false,
2058            edited_buffer: None,
2059        });
2060        cx.emit(Event::ExcerptsAdded {
2061            buffer,
2062            predecessor: prev_excerpt_id,
2063            excerpts,
2064        });
2065        cx.notify();
2066    }
2067
2068    pub fn clear(&mut self, cx: &mut Context<Self>) {
2069        self.sync(cx);
2070        let ids = self.excerpt_ids();
2071        self.buffers.borrow_mut().clear();
2072        let mut snapshot = self.snapshot.borrow_mut();
2073        let start = ExcerptOffset::new(0);
2074        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2075        snapshot.excerpts = Default::default();
2076        snapshot.trailing_excerpt_update_count += 1;
2077        snapshot.is_dirty = false;
2078        snapshot.has_deleted_file = false;
2079        snapshot.has_conflict = false;
2080
2081        self.sync_diff_transforms(
2082            &mut snapshot,
2083            vec![Edit {
2084                old: start..prev_len,
2085                new: start..start,
2086            }],
2087            DiffChangeKind::BufferEdited,
2088        );
2089        cx.emit(Event::Edited {
2090            singleton_buffer_edited: false,
2091            edited_buffer: None,
2092        });
2093        cx.emit(Event::ExcerptsRemoved { ids });
2094        cx.notify();
2095    }
2096
2097    pub fn excerpts_for_buffer(
2098        &self,
2099        buffer_id: BufferId,
2100        cx: &App,
2101    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2102        let mut excerpts = Vec::new();
2103        let snapshot = self.read(cx);
2104        let buffers = self.buffers.borrow();
2105        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2106        for locator in buffers
2107            .get(&buffer_id)
2108            .map(|state| &state.excerpts)
2109            .into_iter()
2110            .flatten()
2111        {
2112            cursor.seek_forward(&Some(locator), Bias::Left, &());
2113            if let Some(excerpt) = cursor.item() {
2114                if excerpt.locator == *locator {
2115                    excerpts.push((excerpt.id, excerpt.range.clone()));
2116                }
2117            }
2118        }
2119
2120        excerpts
2121    }
2122
2123    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2124        let snapshot = self.read(cx);
2125        let buffers = self.buffers.borrow();
2126        let mut excerpts = snapshot
2127            .excerpts
2128            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
2129        let mut diff_transforms = snapshot
2130            .diff_transforms
2131            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
2132        diff_transforms.next(&());
2133        let locators = buffers
2134            .get(&buffer_id)
2135            .into_iter()
2136            .flat_map(|state| &state.excerpts);
2137        let mut result = Vec::new();
2138        for locator in locators {
2139            excerpts.seek_forward(&Some(locator), Bias::Left, &());
2140            if let Some(excerpt) = excerpts.item() {
2141                if excerpt.locator == *locator {
2142                    let excerpt_start = excerpts.start().1.clone();
2143                    let excerpt_end =
2144                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2145
2146                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
2147                    let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2148                    let start = diff_transforms.start().1.0 + overshoot;
2149
2150                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
2151                    let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2152                    let end = diff_transforms.start().1.0 + overshoot;
2153
2154                    result.push(start..end)
2155                }
2156            }
2157        }
2158        result
2159    }
2160
2161    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2162        self.snapshot
2163            .borrow()
2164            .excerpts
2165            .iter()
2166            .map(|entry| entry.buffer_id)
2167            .collect()
2168    }
2169
2170    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2171        self.snapshot
2172            .borrow()
2173            .excerpts
2174            .iter()
2175            .map(|entry| entry.id)
2176            .collect()
2177    }
2178
2179    pub fn excerpt_containing(
2180        &self,
2181        position: impl ToOffset,
2182        cx: &App,
2183    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2184        let snapshot = self.read(cx);
2185        let offset = position.to_offset(&snapshot);
2186
2187        let mut cursor = snapshot.cursor::<usize>();
2188        cursor.seek(&offset);
2189        cursor
2190            .excerpt()
2191            .or_else(|| snapshot.excerpts.last())
2192            .map(|excerpt| {
2193                (
2194                    excerpt.id,
2195                    self.buffers
2196                        .borrow()
2197                        .get(&excerpt.buffer_id)
2198                        .unwrap()
2199                        .buffer
2200                        .clone(),
2201                    excerpt.range.context.clone(),
2202                )
2203            })
2204    }
2205
2206    // If point is at the end of the buffer, the last excerpt is returned
2207    pub fn point_to_buffer_offset<T: ToOffset>(
2208        &self,
2209        point: T,
2210        cx: &App,
2211    ) -> Option<(Entity<Buffer>, usize)> {
2212        let snapshot = self.read(cx);
2213        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2214        Some((
2215            self.buffers
2216                .borrow()
2217                .get(&buffer.remote_id())?
2218                .buffer
2219                .clone(),
2220            offset,
2221        ))
2222    }
2223
2224    // If point is at the end of the buffer, the last excerpt is returned
2225    pub fn point_to_buffer_point<T: ToPoint>(
2226        &self,
2227        point: T,
2228        cx: &App,
2229    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2230        let snapshot = self.read(cx);
2231        let (buffer, point, is_main_buffer) =
2232            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2233        Some((
2234            self.buffers
2235                .borrow()
2236                .get(&buffer.remote_id())?
2237                .buffer
2238                .clone(),
2239            point,
2240            is_main_buffer,
2241        ))
2242    }
2243
2244    pub fn buffer_point_to_anchor(
2245        &self,
2246        buffer: &Entity<Buffer>,
2247        point: Point,
2248        cx: &App,
2249    ) -> Option<Anchor> {
2250        let mut found = None;
2251        let snapshot = buffer.read(cx).snapshot();
2252        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2253            let start = range.context.start.to_point(&snapshot);
2254            let end = range.context.end.to_point(&snapshot);
2255            if start <= point && point < end {
2256                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2257                break;
2258            }
2259            if point < start {
2260                found = Some((start, excerpt_id));
2261            }
2262            if point > end {
2263                found = Some((end, excerpt_id));
2264            }
2265        }
2266
2267        found.map(|(point, excerpt_id)| {
2268            let text_anchor = snapshot.anchor_after(point);
2269            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2270        })
2271    }
2272
2273    pub fn remove_excerpts(
2274        &mut self,
2275        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2276        cx: &mut Context<Self>,
2277    ) {
2278        self.sync(cx);
2279        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2280        if ids.is_empty() {
2281            return;
2282        }
2283
2284        let mut buffers = self.buffers.borrow_mut();
2285        let mut snapshot = self.snapshot.borrow_mut();
2286        let mut new_excerpts = SumTree::default();
2287        let mut cursor = snapshot
2288            .excerpts
2289            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2290        let mut edits = Vec::new();
2291        let mut excerpt_ids = ids.iter().copied().peekable();
2292        let mut removed_buffer_ids = Vec::new();
2293
2294        while let Some(excerpt_id) = excerpt_ids.next() {
2295            self.paths_by_excerpt.remove(&excerpt_id);
2296            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2297            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2298            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2299
2300            if let Some(mut excerpt) = cursor.item() {
2301                if excerpt.id != excerpt_id {
2302                    continue;
2303                }
2304                let mut old_start = cursor.start().1;
2305
2306                // Skip over the removed excerpt.
2307                'remove_excerpts: loop {
2308                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2309                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2310                        if buffer_state.excerpts.is_empty() {
2311                            log::debug!(
2312                                "removing buffer and diff for buffer {}",
2313                                excerpt.buffer_id
2314                            );
2315                            buffers.remove(&excerpt.buffer_id);
2316                            removed_buffer_ids.push(excerpt.buffer_id);
2317                        }
2318                    }
2319                    cursor.next(&());
2320
2321                    // Skip over any subsequent excerpts that are also removed.
2322                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2323                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2324                        if let Some(next_excerpt) = cursor.item() {
2325                            if next_excerpt.locator == *next_locator {
2326                                excerpt_ids.next();
2327                                excerpt = next_excerpt;
2328                                continue 'remove_excerpts;
2329                            }
2330                        }
2331                    }
2332
2333                    break;
2334                }
2335
2336                // When removing the last excerpt, remove the trailing newline from
2337                // the previous excerpt.
2338                if cursor.item().is_none() && old_start.value > 0 {
2339                    old_start.value -= 1;
2340                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2341                }
2342
2343                // Push an edit for the removal of this run of excerpts.
2344                let old_end = cursor.start().1;
2345                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2346                edits.push(Edit {
2347                    old: old_start..old_end,
2348                    new: new_start..new_start,
2349                });
2350            }
2351        }
2352        let suffix = cursor.suffix(&());
2353        let changed_trailing_excerpt = suffix.is_empty();
2354        new_excerpts.append(suffix, &());
2355        drop(cursor);
2356        snapshot.excerpts = new_excerpts;
2357        for buffer_id in removed_buffer_ids {
2358            self.diffs.remove(&buffer_id);
2359            snapshot.diffs.remove(&buffer_id);
2360        }
2361
2362        if changed_trailing_excerpt {
2363            snapshot.trailing_excerpt_update_count += 1;
2364        }
2365
2366        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2367        self.buffer_changed_since_sync.replace(true);
2368        cx.emit(Event::Edited {
2369            singleton_buffer_edited: false,
2370            edited_buffer: None,
2371        });
2372        cx.emit(Event::ExcerptsRemoved { ids });
2373        cx.notify();
2374    }
2375
2376    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2377        &self,
2378        anchors: Anchors,
2379        cx: &mut Context<Self>,
2380    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2381        let borrow = self.buffers.borrow();
2382        let mut error = None;
2383        let mut futures = Vec::new();
2384        for anchor in anchors {
2385            if let Some(buffer_id) = anchor.buffer_id {
2386                if let Some(buffer) = borrow.get(&buffer_id) {
2387                    buffer.buffer.update(cx, |buffer, _| {
2388                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2389                    });
2390                } else {
2391                    error = Some(anyhow!(
2392                        "buffer {buffer_id} is not part of this multi-buffer"
2393                    ));
2394                    break;
2395                }
2396            }
2397        }
2398        async move {
2399            if let Some(error) = error {
2400                Err(error)?;
2401            }
2402            for future in futures {
2403                future.await?;
2404            }
2405            Ok(())
2406        }
2407    }
2408
2409    pub fn text_anchor_for_position<T: ToOffset>(
2410        &self,
2411        position: T,
2412        cx: &App,
2413    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2414        let snapshot = self.read(cx);
2415        let anchor = snapshot.anchor_before(position);
2416        let buffer = self
2417            .buffers
2418            .borrow()
2419            .get(&anchor.buffer_id?)?
2420            .buffer
2421            .clone();
2422        Some((buffer, anchor.text_anchor))
2423    }
2424
2425    fn on_buffer_event(
2426        &mut self,
2427        buffer: Entity<Buffer>,
2428        event: &language::BufferEvent,
2429        cx: &mut Context<Self>,
2430    ) {
2431        cx.emit(match event {
2432            language::BufferEvent::Edited => Event::Edited {
2433                singleton_buffer_edited: true,
2434                edited_buffer: Some(buffer.clone()),
2435            },
2436            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2437            language::BufferEvent::Saved => Event::Saved,
2438            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2439            language::BufferEvent::Reloaded => Event::Reloaded,
2440            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2441            language::BufferEvent::LanguageChanged => {
2442                Event::LanguageChanged(buffer.read(cx).remote_id())
2443            }
2444            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2445            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2446            language::BufferEvent::Closed => Event::Closed,
2447            language::BufferEvent::Discarded => Event::Discarded,
2448            language::BufferEvent::CapabilityChanged => {
2449                self.capability = buffer.read(cx).capability();
2450                Event::CapabilityChanged
2451            }
2452            language::BufferEvent::Operation { .. } => return,
2453        });
2454    }
2455
2456    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2457        self.sync(cx);
2458        let mut snapshot = self.snapshot.borrow_mut();
2459        let diff = diff.read(cx);
2460        let buffer_id = diff.buffer_id;
2461        let diff = diff.snapshot(cx);
2462        snapshot.diffs.insert(buffer_id, diff);
2463    }
2464
2465    fn buffer_diff_changed(
2466        &mut self,
2467        diff: Entity<BufferDiff>,
2468        range: Range<text::Anchor>,
2469        cx: &mut Context<Self>,
2470    ) {
2471        self.sync(cx);
2472        self.buffer_changed_since_sync.replace(true);
2473
2474        let diff = diff.read(cx);
2475        let buffer_id = diff.buffer_id;
2476        let buffers = self.buffers.borrow();
2477        let Some(buffer_state) = buffers.get(&buffer_id) else {
2478            eprintln!("no buffer");
2479            return;
2480        };
2481
2482        let buffer = buffer_state.buffer.read(cx);
2483        let diff_change_range = range.to_offset(buffer);
2484
2485        let new_diff = diff.snapshot(cx);
2486        let mut snapshot = self.snapshot.borrow_mut();
2487        let base_text_changed = snapshot
2488            .diffs
2489            .get(&buffer_id)
2490            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2491
2492        snapshot.diffs.insert(buffer_id, new_diff);
2493
2494        let mut excerpt_edits = Vec::new();
2495        for locator in &buffer_state.excerpts {
2496            let mut cursor = snapshot
2497                .excerpts
2498                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2499            cursor.seek_forward(&Some(locator), Bias::Left, &());
2500            if let Some(excerpt) = cursor.item() {
2501                if excerpt.locator == *locator {
2502                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2503                    if diff_change_range.end < excerpt_buffer_range.start
2504                        || diff_change_range.start > excerpt_buffer_range.end
2505                    {
2506                        continue;
2507                    }
2508                    let excerpt_start = cursor.start().1;
2509                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2510                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2511                        diff_change_range
2512                            .start
2513                            .saturating_sub(excerpt_buffer_range.start),
2514                    );
2515                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2516                        diff_change_range
2517                            .end
2518                            .saturating_sub(excerpt_buffer_range.start),
2519                    );
2520                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2521                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2522                    excerpt_edits.push(Edit {
2523                        old: edit_start..edit_end,
2524                        new: edit_start..edit_end,
2525                    });
2526                }
2527            }
2528        }
2529
2530        self.sync_diff_transforms(
2531            &mut snapshot,
2532            excerpt_edits,
2533            DiffChangeKind::DiffUpdated {
2534                base_changed: base_text_changed,
2535            },
2536        );
2537        cx.emit(Event::Edited {
2538            singleton_buffer_edited: false,
2539            edited_buffer: None,
2540        });
2541    }
2542
2543    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2544        self.buffers
2545            .borrow()
2546            .values()
2547            .map(|state| state.buffer.clone())
2548            .collect()
2549    }
2550
2551    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2552        self.buffers
2553            .borrow()
2554            .get(&buffer_id)
2555            .map(|state| state.buffer.clone())
2556    }
2557
2558    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2559        self.point_to_buffer_offset(point, cx)
2560            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2561    }
2562
2563    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2564        let buffer_id = self
2565            .snapshot
2566            .borrow()
2567            .excerpts
2568            .first()
2569            .map(|excerpt| excerpt.buffer.remote_id());
2570        buffer_id
2571            .and_then(|buffer_id| self.buffer(buffer_id))
2572            .map(|buffer| {
2573                let buffer = buffer.read(cx);
2574                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2575            })
2576            .unwrap_or_else(move || self.language_settings_at(0, cx))
2577    }
2578
2579    pub fn language_settings_at<'a, T: ToOffset>(
2580        &'a self,
2581        point: T,
2582        cx: &'a App,
2583    ) -> Cow<'a, LanguageSettings> {
2584        let mut language = None;
2585        let mut file = None;
2586        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2587            let buffer = buffer.read(cx);
2588            language = buffer.language_at(offset);
2589            file = buffer.file();
2590        }
2591        language_settings(language.map(|l| l.name()), file, cx)
2592    }
2593
2594    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2595        self.buffers
2596            .borrow()
2597            .values()
2598            .for_each(|state| f(&state.buffer))
2599    }
2600
2601    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2602        if let Some(title) = self.title.as_ref() {
2603            return title.into();
2604        }
2605
2606        if let Some(buffer) = self.as_singleton() {
2607            if let Some(file) = buffer.read(cx).file() {
2608                return file.file_name(cx).to_string_lossy();
2609            }
2610        }
2611
2612        "untitled".into()
2613    }
2614
2615    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2616        self.title = Some(title);
2617        cx.notify();
2618    }
2619
2620    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2621    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2622        for buffer_state in self.buffers.borrow().values() {
2623            buffer_state
2624                .buffer
2625                .update(cx, |buffer, _cx| buffer.refresh_preview());
2626        }
2627    }
2628
2629    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2630    pub fn preserve_preview(&self, cx: &App) -> bool {
2631        self.buffers
2632            .borrow()
2633            .values()
2634            .all(|state| state.buffer.read(cx).preserve_preview())
2635    }
2636
2637    #[cfg(any(test, feature = "test-support"))]
2638    pub fn is_parsing(&self, cx: &App) -> bool {
2639        self.as_singleton().unwrap().read(cx).is_parsing()
2640    }
2641
2642    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2643        let buffer_id = diff.read(cx).buffer_id;
2644        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2645        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2646    }
2647
2648    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2649        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2650    }
2651
2652    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2653        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2654    }
2655
2656    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2657        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2658    }
2659
2660    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2661        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2662        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2663    }
2664
2665    pub fn all_diff_hunks_expanded(&self) -> bool {
2666        self.snapshot.borrow().all_diff_hunks_expanded
2667    }
2668
2669    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2670        self.read(cx)
2671            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2672            .nth(1)
2673            .is_some()
2674    }
2675
2676    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2677        let snapshot = self.read(cx);
2678        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2679        let offset_range = range.to_offset(&snapshot);
2680        cursor.seek(&offset_range.start, Bias::Left, &());
2681        while let Some(item) = cursor.item() {
2682            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2683                break;
2684            }
2685            if item.hunk_info().is_some() {
2686                return true;
2687            }
2688            cursor.next(&());
2689        }
2690        false
2691    }
2692
2693    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2694        let snapshot = self.read(cx);
2695        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2696        for range in ranges {
2697            let range = range.to_point(&snapshot);
2698            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2699            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2700            let start = start.saturating_sub(1);
2701            let end = snapshot.len().min(end + 1);
2702            cursor.seek(&start, Bias::Right, &());
2703            while let Some(item) = cursor.item() {
2704                if *cursor.start() >= end {
2705                    break;
2706                }
2707                if item.hunk_info().is_some() {
2708                    return true;
2709                }
2710                cursor.next(&());
2711            }
2712        }
2713        false
2714    }
2715
2716    pub fn expand_or_collapse_diff_hunks_inner(
2717        &mut self,
2718        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2719        expand: bool,
2720        cx: &mut Context<Self>,
2721    ) {
2722        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2723            return;
2724        }
2725        self.sync(cx);
2726        let mut snapshot = self.snapshot.borrow_mut();
2727        let mut excerpt_edits = Vec::new();
2728        for (range, end_excerpt_id) in ranges {
2729            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2730                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2731                    continue;
2732                }
2733                let start = Anchor::in_buffer(
2734                    diff_hunk.excerpt_id,
2735                    diff_hunk.buffer_id,
2736                    diff_hunk.buffer_range.start,
2737                );
2738                let end = Anchor::in_buffer(
2739                    diff_hunk.excerpt_id,
2740                    diff_hunk.buffer_id,
2741                    diff_hunk.buffer_range.end,
2742                );
2743                let start = snapshot.excerpt_offset_for_anchor(&start);
2744                let end = snapshot.excerpt_offset_for_anchor(&end);
2745                excerpt_edits.push(text::Edit {
2746                    old: start..end,
2747                    new: start..end,
2748                });
2749            }
2750        }
2751
2752        self.sync_diff_transforms(
2753            &mut snapshot,
2754            excerpt_edits,
2755            DiffChangeKind::ExpandOrCollapseHunks { expand },
2756        );
2757        cx.emit(Event::DiffHunksToggled);
2758        cx.emit(Event::Edited {
2759            singleton_buffer_edited: false,
2760            edited_buffer: None,
2761        });
2762    }
2763
2764    pub fn expand_or_collapse_diff_hunks(
2765        &mut self,
2766        ranges: Vec<Range<Anchor>>,
2767        expand: bool,
2768        cx: &mut Context<Self>,
2769    ) {
2770        let snapshot = self.snapshot.borrow().clone();
2771        let ranges = ranges.iter().map(move |range| {
2772            let end_excerpt_id = range.end.excerpt_id;
2773            let range = range.to_point(&snapshot);
2774            let mut peek_end = range.end;
2775            if range.end.row < snapshot.max_row().0 {
2776                peek_end = Point::new(range.end.row + 1, 0);
2777            };
2778            (range.start..peek_end, end_excerpt_id)
2779        });
2780        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2781    }
2782
2783    pub fn resize_excerpt(
2784        &mut self,
2785        id: ExcerptId,
2786        range: Range<text::Anchor>,
2787        cx: &mut Context<Self>,
2788    ) {
2789        self.sync(cx);
2790
2791        let mut snapshot = self.snapshot.borrow_mut();
2792        let locator = snapshot.excerpt_locator_for_id(id);
2793        let mut new_excerpts = SumTree::default();
2794        let mut cursor = snapshot
2795            .excerpts
2796            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2797        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2798
2799        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2800        new_excerpts.append(prefix, &());
2801
2802        let mut excerpt = cursor.item().unwrap().clone();
2803        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2804
2805        excerpt.range.context.start = range.start;
2806        excerpt.range.context.end = range.end;
2807        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2808
2809        excerpt.text_summary = excerpt
2810            .buffer
2811            .text_summary_for_range(excerpt.range.context.clone());
2812
2813        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2814        let old_start_offset = cursor.start().1;
2815        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2816        let edit = Edit {
2817            old: old_start_offset..old_start_offset + old_text_len,
2818            new: new_start_offset..new_start_offset + new_text_len,
2819        };
2820
2821        if let Some(last_edit) = edits.last_mut() {
2822            if last_edit.old.end == edit.old.start {
2823                last_edit.old.end = edit.old.end;
2824                last_edit.new.end = edit.new.end;
2825            } else {
2826                edits.push(edit);
2827            }
2828        } else {
2829            edits.push(edit);
2830        }
2831
2832        new_excerpts.push(excerpt, &());
2833
2834        cursor.next(&());
2835
2836        new_excerpts.append(cursor.suffix(&()), &());
2837
2838        drop(cursor);
2839        snapshot.excerpts = new_excerpts;
2840
2841        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2842        cx.emit(Event::Edited {
2843            singleton_buffer_edited: false,
2844            edited_buffer: None,
2845        });
2846        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2847        cx.notify();
2848    }
2849
2850    pub fn expand_excerpts(
2851        &mut self,
2852        ids: impl IntoIterator<Item = ExcerptId>,
2853        line_count: u32,
2854        direction: ExpandExcerptDirection,
2855        cx: &mut Context<Self>,
2856    ) {
2857        if line_count == 0 {
2858            return;
2859        }
2860        self.sync(cx);
2861        if !self.excerpts_by_path.is_empty() {
2862            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2863            return;
2864        }
2865        let mut snapshot = self.snapshot.borrow_mut();
2866
2867        let ids = ids.into_iter().collect::<Vec<_>>();
2868        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2869        let mut new_excerpts = SumTree::default();
2870        let mut cursor = snapshot
2871            .excerpts
2872            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2873        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2874
2875        for locator in &locators {
2876            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2877            new_excerpts.append(prefix, &());
2878
2879            let mut excerpt = cursor.item().unwrap().clone();
2880            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2881
2882            let up_line_count = if direction.should_expand_up() {
2883                line_count
2884            } else {
2885                0
2886            };
2887
2888            let start_row = excerpt
2889                .range
2890                .context
2891                .start
2892                .to_point(&excerpt.buffer)
2893                .row
2894                .saturating_sub(up_line_count);
2895            let start_point = Point::new(start_row, 0);
2896            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2897
2898            let down_line_count = if direction.should_expand_down() {
2899                line_count
2900            } else {
2901                0
2902            };
2903
2904            let mut end_point = excerpt.buffer.clip_point(
2905                excerpt.range.context.end.to_point(&excerpt.buffer)
2906                    + Point::new(down_line_count, 0),
2907                Bias::Left,
2908            );
2909            end_point.column = excerpt.buffer.line_len(end_point.row);
2910            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2911            excerpt.max_buffer_row = end_point.row;
2912
2913            excerpt.text_summary = excerpt
2914                .buffer
2915                .text_summary_for_range(excerpt.range.context.clone());
2916
2917            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2918            let old_start_offset = cursor.start().1;
2919            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2920            let edit = Edit {
2921                old: old_start_offset..old_start_offset + old_text_len,
2922                new: new_start_offset..new_start_offset + new_text_len,
2923            };
2924
2925            if let Some(last_edit) = edits.last_mut() {
2926                if last_edit.old.end == edit.old.start {
2927                    last_edit.old.end = edit.old.end;
2928                    last_edit.new.end = edit.new.end;
2929                } else {
2930                    edits.push(edit);
2931                }
2932            } else {
2933                edits.push(edit);
2934            }
2935
2936            new_excerpts.push(excerpt, &());
2937
2938            cursor.next(&());
2939        }
2940
2941        new_excerpts.append(cursor.suffix(&()), &());
2942
2943        drop(cursor);
2944        snapshot.excerpts = new_excerpts;
2945
2946        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2947        cx.emit(Event::Edited {
2948            singleton_buffer_edited: false,
2949            edited_buffer: None,
2950        });
2951        cx.emit(Event::ExcerptsExpanded { ids });
2952        cx.notify();
2953    }
2954
2955    fn sync(&self, cx: &App) {
2956        let changed = self.buffer_changed_since_sync.replace(false);
2957        if !changed {
2958            return;
2959        }
2960
2961        let mut snapshot = self.snapshot.borrow_mut();
2962        let mut excerpts_to_edit = Vec::new();
2963        let mut non_text_state_updated = false;
2964        let mut is_dirty = false;
2965        let mut has_deleted_file = false;
2966        let mut has_conflict = false;
2967        let mut edited = false;
2968        let mut buffers = self.buffers.borrow_mut();
2969        for buffer_state in buffers.values_mut() {
2970            let buffer = buffer_state.buffer.read(cx);
2971            let version = buffer.version();
2972            let non_text_state_update_count = buffer.non_text_state_update_count();
2973
2974            let buffer_edited = version.changed_since(&buffer_state.last_version);
2975            let buffer_non_text_state_updated =
2976                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2977            if buffer_edited || buffer_non_text_state_updated {
2978                buffer_state.last_version = version;
2979                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2980                excerpts_to_edit.extend(
2981                    buffer_state
2982                        .excerpts
2983                        .iter()
2984                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2985                );
2986            }
2987
2988            edited |= buffer_edited;
2989            non_text_state_updated |= buffer_non_text_state_updated;
2990            is_dirty |= buffer.is_dirty();
2991            has_deleted_file |= buffer
2992                .file()
2993                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2994            has_conflict |= buffer.has_conflict();
2995        }
2996        if edited {
2997            snapshot.edit_count += 1;
2998        }
2999        if non_text_state_updated {
3000            snapshot.non_text_state_update_count += 1;
3001        }
3002        snapshot.is_dirty = is_dirty;
3003        snapshot.has_deleted_file = has_deleted_file;
3004        snapshot.has_conflict = has_conflict;
3005
3006        for (id, diff) in self.diffs.iter() {
3007            if snapshot.diffs.get(&id).is_none() {
3008                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3009            }
3010        }
3011
3012        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3013
3014        let mut edits = Vec::new();
3015        let mut new_excerpts = SumTree::default();
3016        let mut cursor = snapshot
3017            .excerpts
3018            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
3019
3020        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3021            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
3022            let old_excerpt = cursor.item().unwrap();
3023            let buffer = buffer.read(cx);
3024            let buffer_id = buffer.remote_id();
3025
3026            let mut new_excerpt;
3027            if buffer_edited {
3028                edits.extend(
3029                    buffer
3030                        .edits_since_in_range::<usize>(
3031                            old_excerpt.buffer.version(),
3032                            old_excerpt.range.context.clone(),
3033                        )
3034                        .map(|edit| {
3035                            let excerpt_old_start = cursor.start().1;
3036                            let excerpt_new_start =
3037                                ExcerptOffset::new(new_excerpts.summary().text.len);
3038                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3039                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3040                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3041                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3042                            Edit {
3043                                old: old_start..old_end,
3044                                new: new_start..new_end,
3045                            }
3046                        }),
3047                );
3048
3049                new_excerpt = Excerpt::new(
3050                    old_excerpt.id,
3051                    locator.clone(),
3052                    buffer_id,
3053                    buffer.snapshot(),
3054                    old_excerpt.range.clone(),
3055                    old_excerpt.has_trailing_newline,
3056                );
3057            } else {
3058                new_excerpt = old_excerpt.clone();
3059                new_excerpt.buffer = buffer.snapshot();
3060            }
3061
3062            new_excerpts.push(new_excerpt, &());
3063            cursor.next(&());
3064        }
3065        new_excerpts.append(cursor.suffix(&()), &());
3066
3067        drop(cursor);
3068        snapshot.excerpts = new_excerpts;
3069
3070        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3071    }
3072
3073    fn sync_diff_transforms(
3074        &self,
3075        snapshot: &mut MultiBufferSnapshot,
3076        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3077        change_kind: DiffChangeKind,
3078    ) {
3079        if excerpt_edits.is_empty() {
3080            return;
3081        }
3082
3083        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3084        let mut old_diff_transforms = snapshot
3085            .diff_transforms
3086            .cursor::<(ExcerptOffset, usize)>(&());
3087        let mut new_diff_transforms = SumTree::default();
3088        let mut old_expanded_hunks = HashSet::default();
3089        let mut output_edits = Vec::new();
3090        let mut output_delta = 0_isize;
3091        let mut at_transform_boundary = true;
3092        let mut end_of_current_insert = None;
3093
3094        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3095        while let Some(edit) = excerpt_edits.next() {
3096            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
3097            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3098                excerpts.prev(&());
3099            }
3100
3101            // Keep any transforms that are before the edit.
3102            if at_transform_boundary {
3103                at_transform_boundary = false;
3104                let transforms_before_edit =
3105                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3106                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3107                if let Some(transform) = old_diff_transforms.item() {
3108                    if old_diff_transforms.end(&()).0 == edit.old.start
3109                        && old_diff_transforms.start().0 < edit.old.start
3110                    {
3111                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3112                        old_diff_transforms.next(&());
3113                    }
3114                }
3115            }
3116
3117            // Compute the start of the edit in output coordinates.
3118            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3119            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3120            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3121
3122            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3123                &edit,
3124                &mut excerpts,
3125                &mut old_diff_transforms,
3126                &mut new_diff_transforms,
3127                &mut end_of_current_insert,
3128                &mut old_expanded_hunks,
3129                &snapshot,
3130                change_kind,
3131            );
3132
3133            // Compute the end of the edit in output coordinates.
3134            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3135            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3136            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3137            let edit_new_end =
3138                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3139            let output_edit = Edit {
3140                old: edit_old_start..edit_old_end,
3141                new: edit_new_start..edit_new_end,
3142            };
3143
3144            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3145            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3146            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3147                output_edits.push(output_edit);
3148            }
3149
3150            // If this is the last edit that intersects the current diff transform,
3151            // then recreate the content up to the end of this transform, to prepare
3152            // for reusing additional slices of the old transforms.
3153            if excerpt_edits.peek().map_or(true, |next_edit| {
3154                next_edit.old.start >= old_diff_transforms.end(&()).0
3155            }) {
3156                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3157                    && match old_diff_transforms.item() {
3158                        Some(DiffTransform::BufferContent {
3159                            inserted_hunk_info: Some(hunk),
3160                            ..
3161                        }) => excerpts.item().is_some_and(|excerpt| {
3162                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3163                        }),
3164                        _ => true,
3165                    };
3166
3167                let mut excerpt_offset = edit.new.end;
3168                if !keep_next_old_transform {
3169                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3170                    old_diff_transforms.next(&());
3171                }
3172
3173                old_expanded_hunks.clear();
3174                self.push_buffer_content_transform(
3175                    &snapshot,
3176                    &mut new_diff_transforms,
3177                    excerpt_offset,
3178                    end_of_current_insert,
3179                );
3180                at_transform_boundary = true;
3181            }
3182        }
3183
3184        // Keep any transforms that are after the last edit.
3185        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3186
3187        // Ensure there's always at least one buffer content transform.
3188        if new_diff_transforms.is_empty() {
3189            new_diff_transforms.push(
3190                DiffTransform::BufferContent {
3191                    summary: Default::default(),
3192                    inserted_hunk_info: None,
3193                },
3194                &(),
3195            );
3196        }
3197
3198        self.subscriptions.publish(output_edits);
3199        drop(old_diff_transforms);
3200        drop(excerpts);
3201        snapshot.diff_transforms = new_diff_transforms;
3202        snapshot.edit_count += 1;
3203
3204        #[cfg(any(test, feature = "test-support"))]
3205        snapshot.check_invariants();
3206    }
3207
3208    fn recompute_diff_transforms_for_edit(
3209        &self,
3210        edit: &Edit<TypedOffset<Excerpt>>,
3211        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3212        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3213        new_diff_transforms: &mut SumTree<DiffTransform>,
3214        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3215        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3216        snapshot: &MultiBufferSnapshot,
3217        change_kind: DiffChangeKind,
3218    ) -> bool {
3219        log::trace!(
3220            "recomputing diff transform for edit {:?} => {:?}",
3221            edit.old.start.value..edit.old.end.value,
3222            edit.new.start.value..edit.new.end.value
3223        );
3224
3225        // Record which hunks were previously expanded.
3226        while let Some(item) = old_diff_transforms.item() {
3227            if let Some(hunk_info) = item.hunk_info() {
3228                log::trace!(
3229                    "previously expanded hunk at {}",
3230                    old_diff_transforms.start().0
3231                );
3232                old_expanded_hunks.insert(hunk_info);
3233            }
3234            if old_diff_transforms.end(&()).0 > edit.old.end {
3235                break;
3236            }
3237            old_diff_transforms.next(&());
3238        }
3239
3240        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3241        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3242        if old_expanded_hunks.is_empty()
3243            && change_kind == DiffChangeKind::BufferEdited
3244            && !all_diff_hunks_expanded
3245        {
3246            return false;
3247        }
3248
3249        // Visit each excerpt that intersects the edit.
3250        let mut did_expand_hunks = false;
3251        while let Some(excerpt) = excerpts.item() {
3252            // Recompute the expanded hunks in the portion of the excerpt that
3253            // intersects the edit.
3254            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3255                let buffer = &excerpt.buffer;
3256                let excerpt_start = *excerpts.start();
3257                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3258                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3259                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3260                let edit_buffer_start =
3261                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3262                let edit_buffer_end =
3263                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3264                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3265                let edit_anchor_range =
3266                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3267
3268                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3269                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3270                        continue;
3271                    }
3272
3273                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3274                    if hunk_buffer_range.start < excerpt_buffer_start {
3275                        log::trace!("skipping hunk that starts before excerpt");
3276                        continue;
3277                    }
3278
3279                    let hunk_info = DiffTransformHunkInfo {
3280                        excerpt_id: excerpt.id,
3281                        hunk_start_anchor: hunk.buffer_range.start,
3282                        hunk_secondary_status: hunk.secondary_status,
3283                    };
3284
3285                    let hunk_excerpt_start = excerpt_start
3286                        + ExcerptOffset::new(
3287                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3288                        );
3289                    let hunk_excerpt_end = excerpt_end.min(
3290                        excerpt_start
3291                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3292                    );
3293
3294                    self.push_buffer_content_transform(
3295                        snapshot,
3296                        new_diff_transforms,
3297                        hunk_excerpt_start,
3298                        *end_of_current_insert,
3299                    );
3300
3301                    // For every existing hunk, determine if it was previously expanded
3302                    // and if it should currently be expanded.
3303                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3304                    let should_expand_hunk = match &change_kind {
3305                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3306                            was_previously_expanded || all_diff_hunks_expanded
3307                        }
3308                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3309                            let intersects = hunk_buffer_range.is_empty()
3310                                || hunk_buffer_range.end > edit_buffer_start;
3311                            if *expand {
3312                                intersects || was_previously_expanded || all_diff_hunks_expanded
3313                            } else {
3314                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3315                            }
3316                        }
3317                        _ => was_previously_expanded || all_diff_hunks_expanded,
3318                    };
3319
3320                    if should_expand_hunk {
3321                        did_expand_hunks = true;
3322                        log::trace!(
3323                            "expanding hunk {:?}, excerpt:{:?}",
3324                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3325                            excerpt.id
3326                        );
3327
3328                        if !hunk.diff_base_byte_range.is_empty()
3329                            && hunk_buffer_range.start >= edit_buffer_start
3330                            && hunk_buffer_range.start <= excerpt_buffer_end
3331                        {
3332                            let base_text = diff.base_text();
3333                            let mut text_cursor =
3334                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3335                            let mut base_text_summary =
3336                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3337
3338                            let mut has_trailing_newline = false;
3339                            if base_text_summary.last_line_chars > 0 {
3340                                base_text_summary += TextSummary::newline();
3341                                has_trailing_newline = true;
3342                            }
3343
3344                            new_diff_transforms.push(
3345                                DiffTransform::DeletedHunk {
3346                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3347                                    summary: base_text_summary,
3348                                    buffer_id: excerpt.buffer_id,
3349                                    hunk_info,
3350                                    has_trailing_newline,
3351                                },
3352                                &(),
3353                            );
3354                        }
3355
3356                        if !hunk_buffer_range.is_empty() {
3357                            *end_of_current_insert =
3358                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3359                        }
3360                    }
3361                }
3362            }
3363
3364            if excerpts.end(&()) <= edit.new.end {
3365                excerpts.next(&());
3366            } else {
3367                break;
3368            }
3369        }
3370
3371        did_expand_hunks || !old_expanded_hunks.is_empty()
3372    }
3373
3374    fn append_diff_transforms(
3375        &self,
3376        new_transforms: &mut SumTree<DiffTransform>,
3377        subtree: SumTree<DiffTransform>,
3378    ) {
3379        if let Some(DiffTransform::BufferContent {
3380            inserted_hunk_info,
3381            summary,
3382        }) = subtree.first()
3383        {
3384            if self.extend_last_buffer_content_transform(
3385                new_transforms,
3386                *inserted_hunk_info,
3387                *summary,
3388            ) {
3389                let mut cursor = subtree.cursor::<()>(&());
3390                cursor.next(&());
3391                cursor.next(&());
3392                new_transforms.append(cursor.suffix(&()), &());
3393                return;
3394            }
3395        }
3396        new_transforms.append(subtree, &());
3397    }
3398
3399    fn push_diff_transform(
3400        &self,
3401        new_transforms: &mut SumTree<DiffTransform>,
3402        transform: DiffTransform,
3403    ) {
3404        if let DiffTransform::BufferContent {
3405            inserted_hunk_info: inserted_hunk_anchor,
3406            summary,
3407        } = transform
3408        {
3409            if self.extend_last_buffer_content_transform(
3410                new_transforms,
3411                inserted_hunk_anchor,
3412                summary,
3413            ) {
3414                return;
3415            }
3416        }
3417        new_transforms.push(transform, &());
3418    }
3419
3420    fn push_buffer_content_transform(
3421        &self,
3422        old_snapshot: &MultiBufferSnapshot,
3423        new_transforms: &mut SumTree<DiffTransform>,
3424        end_offset: ExcerptOffset,
3425        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3426    ) {
3427        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3428            (end_offset.min(insertion_end_offset), Some(hunk_info))
3429        });
3430        let unchanged_region = [(end_offset, None)];
3431
3432        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3433        {
3434            let start_offset = new_transforms.summary().excerpt_len();
3435            if end_offset <= start_offset {
3436                continue;
3437            }
3438            let summary_to_add = old_snapshot
3439                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3440
3441            if !self.extend_last_buffer_content_transform(
3442                new_transforms,
3443                inserted_hunk_info,
3444                summary_to_add,
3445            ) {
3446                new_transforms.push(
3447                    DiffTransform::BufferContent {
3448                        summary: summary_to_add,
3449                        inserted_hunk_info,
3450                    },
3451                    &(),
3452                )
3453            }
3454        }
3455    }
3456
3457    fn extend_last_buffer_content_transform(
3458        &self,
3459        new_transforms: &mut SumTree<DiffTransform>,
3460        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3461        summary_to_add: TextSummary,
3462    ) -> bool {
3463        let mut did_extend = false;
3464        new_transforms.update_last(
3465            |last_transform| {
3466                if let DiffTransform::BufferContent {
3467                    summary,
3468                    inserted_hunk_info: inserted_hunk_anchor,
3469                } = last_transform
3470                {
3471                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3472                        *summary += summary_to_add;
3473                        did_extend = true;
3474                    }
3475                }
3476            },
3477            &(),
3478        );
3479        did_extend
3480    }
3481}
3482
3483#[cfg(any(test, feature = "test-support"))]
3484impl MultiBuffer {
3485    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3486        let buffer = cx.new(|cx| Buffer::local(text, cx));
3487        cx.new(|cx| Self::singleton(buffer, cx))
3488    }
3489
3490    pub fn build_multi<const COUNT: usize>(
3491        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3492        cx: &mut gpui::App,
3493    ) -> Entity<Self> {
3494        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3495        for (text, ranges) in excerpts {
3496            let buffer = cx.new(|cx| Buffer::local(text, cx));
3497            let excerpt_ranges = ranges
3498                .into_iter()
3499                .map(|range| ExcerptRange::new(range.clone()));
3500            multi.update(cx, |multi, cx| {
3501                multi.push_excerpts(buffer, excerpt_ranges, cx)
3502            });
3503        }
3504
3505        multi
3506    }
3507
3508    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3509        cx.new(|cx| Self::singleton(buffer, cx))
3510    }
3511
3512    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3513        cx.new(|cx| {
3514            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3515            let mutation_count = rng.gen_range(1..=5);
3516            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3517            multibuffer
3518        })
3519    }
3520
3521    pub fn randomly_edit(
3522        &mut self,
3523        rng: &mut impl rand::Rng,
3524        edit_count: usize,
3525        cx: &mut Context<Self>,
3526    ) {
3527        use util::RandomCharIter;
3528
3529        let snapshot = self.read(cx);
3530        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3531        let mut last_end = None;
3532        for _ in 0..edit_count {
3533            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3534                break;
3535            }
3536
3537            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3538            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3539            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3540            last_end = Some(end);
3541
3542            let mut range = start..end;
3543            if rng.gen_bool(0.2) {
3544                mem::swap(&mut range.start, &mut range.end);
3545            }
3546
3547            let new_text_len = rng.gen_range(0..10);
3548            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3549
3550            edits.push((range, new_text.into()));
3551        }
3552        log::info!("mutating multi-buffer with {:?}", edits);
3553        drop(snapshot);
3554
3555        self.edit(edits, None, cx);
3556    }
3557
3558    pub fn randomly_edit_excerpts(
3559        &mut self,
3560        rng: &mut impl rand::Rng,
3561        mutation_count: usize,
3562        cx: &mut Context<Self>,
3563    ) {
3564        use rand::prelude::*;
3565        use std::env;
3566        use util::RandomCharIter;
3567
3568        let max_excerpts = env::var("MAX_EXCERPTS")
3569            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3570            .unwrap_or(5);
3571
3572        let mut buffers = Vec::new();
3573        for _ in 0..mutation_count {
3574            if rng.gen_bool(0.05) {
3575                log::info!("Clearing multi-buffer");
3576                self.clear(cx);
3577                continue;
3578            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3579                let ids = self.excerpt_ids();
3580                let mut excerpts = HashSet::default();
3581                for _ in 0..rng.gen_range(0..ids.len()) {
3582                    excerpts.extend(ids.choose(rng).copied());
3583                }
3584
3585                let line_count = rng.gen_range(0..5);
3586
3587                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3588
3589                self.expand_excerpts(
3590                    excerpts.iter().cloned(),
3591                    line_count,
3592                    ExpandExcerptDirection::UpAndDown,
3593                    cx,
3594                );
3595                continue;
3596            }
3597
3598            let excerpt_ids = self.excerpt_ids();
3599            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3600                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3601                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3602                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3603                    let buffer = buffers.last().unwrap().read(cx);
3604                    log::info!(
3605                        "Creating new buffer {} with text: {:?}",
3606                        buffer.remote_id(),
3607                        buffer.text()
3608                    );
3609                    buffers.last().unwrap().clone()
3610                } else {
3611                    self.buffers
3612                        .borrow()
3613                        .values()
3614                        .choose(rng)
3615                        .unwrap()
3616                        .buffer
3617                        .clone()
3618                };
3619
3620                let buffer = buffer_handle.read(cx);
3621                let buffer_text = buffer.text();
3622                let ranges = (0..rng.gen_range(0..5))
3623                    .map(|_| {
3624                        let end_ix =
3625                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3626                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3627                        ExcerptRange::new(start_ix..end_ix)
3628                    })
3629                    .collect::<Vec<_>>();
3630                log::info!(
3631                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3632                    buffer_handle.read(cx).remote_id(),
3633                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3634                    ranges
3635                        .iter()
3636                        .map(|r| &buffer_text[r.context.clone()])
3637                        .collect::<Vec<_>>()
3638                );
3639
3640                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3641                log::info!("Inserted with ids: {:?}", excerpt_id);
3642            } else {
3643                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3644                let mut excerpts_to_remove = excerpt_ids
3645                    .choose_multiple(rng, remove_count)
3646                    .cloned()
3647                    .collect::<Vec<_>>();
3648                let snapshot = self.snapshot.borrow();
3649                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3650                drop(snapshot);
3651                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3652                self.remove_excerpts(excerpts_to_remove, cx);
3653            }
3654        }
3655    }
3656
3657    pub fn randomly_mutate(
3658        &mut self,
3659        rng: &mut impl rand::Rng,
3660        mutation_count: usize,
3661        cx: &mut Context<Self>,
3662    ) {
3663        use rand::prelude::*;
3664
3665        if rng.gen_bool(0.7) || self.singleton {
3666            let buffer = self
3667                .buffers
3668                .borrow()
3669                .values()
3670                .choose(rng)
3671                .map(|state| state.buffer.clone());
3672
3673            if let Some(buffer) = buffer {
3674                buffer.update(cx, |buffer, cx| {
3675                    if rng.r#gen() {
3676                        buffer.randomly_edit(rng, mutation_count, cx);
3677                    } else {
3678                        buffer.randomly_undo_redo(rng, cx);
3679                    }
3680                });
3681            } else {
3682                self.randomly_edit(rng, mutation_count, cx);
3683            }
3684        } else {
3685            self.randomly_edit_excerpts(rng, mutation_count, cx);
3686        }
3687
3688        self.check_invariants(cx);
3689    }
3690
3691    fn check_invariants(&self, cx: &App) {
3692        self.read(cx).check_invariants();
3693    }
3694}
3695
3696impl EventEmitter<Event> for MultiBuffer {}
3697
3698impl MultiBufferSnapshot {
3699    pub fn text(&self) -> String {
3700        self.chunks(0..self.len(), false)
3701            .map(|chunk| chunk.text)
3702            .collect()
3703    }
3704
3705    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3706        self.reversed_chunks_in_range(0..position.to_offset(self))
3707            .flat_map(|c| c.chars().rev())
3708    }
3709
3710    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3711        let mut cursor = self.cursor::<usize>();
3712        cursor.seek(&range.end);
3713        let current_chunks = cursor.region().as_ref().map(|region| {
3714            let start_overshoot = range.start.saturating_sub(region.range.start);
3715            let end_overshoot = range.end - region.range.start;
3716            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3717            let start = region.buffer_range.start + start_overshoot;
3718            region.buffer.reversed_chunks_in_range(start..end)
3719        });
3720        ReversedMultiBufferChunks {
3721            cursor,
3722            current_chunks,
3723            start: range.start,
3724            offset: range.end,
3725        }
3726    }
3727
3728    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3729        let offset = position.to_offset(self);
3730        self.text_for_range(offset..self.len())
3731            .flat_map(|chunk| chunk.chars())
3732    }
3733
3734    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3735        self.chunks(range, false).map(|chunk| chunk.text)
3736    }
3737
3738    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3739        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3740            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3741    }
3742
3743    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3744    where
3745        T: ToOffset,
3746    {
3747        let position = position.to_offset(self);
3748        position == self.clip_offset(position, Bias::Left)
3749            && self
3750                .bytes_in_range(position..self.len())
3751                .flatten()
3752                .copied()
3753                .take(needle.len())
3754                .eq(needle.bytes())
3755    }
3756
3757    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3758        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3759    }
3760
3761    pub fn diff_hunks_in_range<T: ToPoint>(
3762        &self,
3763        range: Range<T>,
3764    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3765        let query_range = range.start.to_point(self)..range.end.to_point(self);
3766        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3767            let diff = self.diffs.get(&buffer.remote_id())?;
3768            let buffer_start = buffer.anchor_before(buffer_range.start);
3769            let buffer_end = buffer.anchor_after(buffer_range.end);
3770            Some(
3771                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3772                    .filter_map(|hunk| {
3773                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3774                            return None;
3775                        }
3776                        Some((hunk.range.clone(), hunk))
3777                    }),
3778            )
3779        })
3780        .filter_map(move |(range, hunk, excerpt)| {
3781            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3782            {
3783                return None;
3784            }
3785            let end_row = if range.end.column == 0 {
3786                range.end.row
3787            } else {
3788                range.end.row + 1
3789            };
3790            Some(MultiBufferDiffHunk {
3791                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3792                buffer_id: excerpt.buffer_id,
3793                excerpt_id: excerpt.id,
3794                buffer_range: hunk.buffer_range.clone(),
3795                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3796                secondary_status: hunk.secondary_status,
3797            })
3798        })
3799    }
3800
3801    pub fn excerpt_ids_for_range<T: ToOffset>(
3802        &self,
3803        range: Range<T>,
3804    ) -> impl Iterator<Item = ExcerptId> + '_ {
3805        let range = range.start.to_offset(self)..range.end.to_offset(self);
3806        let mut cursor = self.cursor::<usize>();
3807        cursor.seek(&range.start);
3808        std::iter::from_fn(move || {
3809            let region = cursor.region()?;
3810            if region.range.start >= range.end {
3811                return None;
3812            }
3813            cursor.next_excerpt();
3814            Some(region.excerpt.id)
3815        })
3816    }
3817
3818    pub fn buffer_ids_for_range<T: ToOffset>(
3819        &self,
3820        range: Range<T>,
3821    ) -> impl Iterator<Item = BufferId> + '_ {
3822        let range = range.start.to_offset(self)..range.end.to_offset(self);
3823        let mut cursor = self.cursor::<usize>();
3824        cursor.seek(&range.start);
3825        std::iter::from_fn(move || {
3826            let region = cursor.region()?;
3827            if region.range.start > range.end
3828                || region.range.start == range.end && region.range.start > range.start
3829            {
3830                return None;
3831            }
3832            cursor.next_excerpt();
3833            Some(region.excerpt.buffer_id)
3834        })
3835    }
3836
3837    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3838        &self,
3839        ranges: impl Iterator<Item = Range<T>>,
3840    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3841        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3842    }
3843
3844    pub fn range_to_buffer_ranges<T: ToOffset>(
3845        &self,
3846        range: Range<T>,
3847    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3848        let start = range.start.to_offset(&self);
3849        let end = range.end.to_offset(&self);
3850
3851        let mut cursor = self.cursor::<usize>();
3852        cursor.seek(&start);
3853
3854        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3855        while let Some(region) = cursor.region() {
3856            if region.range.start > end {
3857                break;
3858            }
3859            if region.is_main_buffer {
3860                let start_overshoot = start.saturating_sub(region.range.start);
3861                let end_overshoot = end.saturating_sub(region.range.start);
3862                let start = region
3863                    .buffer_range
3864                    .end
3865                    .min(region.buffer_range.start + start_overshoot);
3866                let end = region
3867                    .buffer_range
3868                    .end
3869                    .min(region.buffer_range.start + end_overshoot);
3870                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3871                    *excerpt_id == region.excerpt.id && prev_range.end == start
3872                }) {
3873                    prev.1.end = end;
3874                } else {
3875                    result.push((region.buffer, start..end, region.excerpt.id));
3876                }
3877            }
3878            cursor.next();
3879        }
3880        result
3881    }
3882
3883    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3884        &self,
3885        range: Range<T>,
3886    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3887        let start = range.start.to_offset(&self);
3888        let end = range.end.to_offset(&self);
3889
3890        let mut cursor = self.cursor::<usize>();
3891        cursor.seek(&start);
3892
3893        std::iter::from_fn(move || {
3894            let region = cursor.region()?;
3895            if region.range.start > end {
3896                return None;
3897            }
3898            let start_overshoot = start.saturating_sub(region.range.start);
3899            let end_overshoot = end.saturating_sub(region.range.start);
3900            let start = region
3901                .buffer_range
3902                .end
3903                .min(region.buffer_range.start + start_overshoot);
3904            let end = region
3905                .buffer_range
3906                .end
3907                .min(region.buffer_range.start + end_overshoot);
3908
3909            let region_excerpt_id = region.excerpt.id;
3910            let deleted_hunk_anchor = if region.is_main_buffer {
3911                None
3912            } else {
3913                Some(self.anchor_before(region.range.start))
3914            };
3915            let result = (
3916                region.buffer,
3917                start..end,
3918                region_excerpt_id,
3919                deleted_hunk_anchor,
3920            );
3921            cursor.next();
3922            Some(result)
3923        })
3924    }
3925
3926    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3927    /// coordinates.
3928    ///
3929    /// The given callback will be called for every excerpt intersecting the given range. It will
3930    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3931    /// The callback should return an iterator of metadata items from that buffer, each paired
3932    /// with a buffer range.
3933    ///
3934    /// The returned iterator yields each of these metadata items, paired with its range in
3935    /// multi-buffer coordinates.
3936    fn lift_buffer_metadata<'a, D, M, I>(
3937        &'a self,
3938        query_range: Range<D>,
3939        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3940    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3941    where
3942        I: Iterator<Item = (Range<D>, M)> + 'a,
3943        D: TextDimension + Ord + Sub<D, Output = D>,
3944    {
3945        let max_position = D::from_text_summary(&self.text_summary());
3946        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3947        let mut cursor = self.cursor::<D>();
3948
3949        // Find the excerpt and buffer offset where the given range ends.
3950        cursor.seek(&query_range.end);
3951        let mut range_end = None;
3952        while let Some(region) = cursor.region() {
3953            if region.is_main_buffer {
3954                let mut buffer_end = region.buffer_range.start;
3955                let overshoot = if query_range.end > region.range.start {
3956                    query_range.end - region.range.start
3957                } else {
3958                    D::default()
3959                };
3960                buffer_end.add_assign(&overshoot);
3961                range_end = Some((region.excerpt.id, buffer_end));
3962                break;
3963            }
3964            cursor.next();
3965        }
3966
3967        cursor.seek(&query_range.start);
3968
3969        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3970            if region.range.start > D::zero(&()) {
3971                cursor.prev()
3972            }
3973        }
3974
3975        iter::from_fn(move || {
3976            loop {
3977                let excerpt = cursor.excerpt()?;
3978
3979                // If we have already retrieved metadata for this excerpt, continue to use it.
3980                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3981                    .as_mut()
3982                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3983                {
3984                    Some(metadata)
3985                }
3986                // Otherwise, compute the intersection of the input range with the excerpt's range,
3987                // and retrieve the metadata for the resulting range.
3988                else {
3989                    let region = cursor.region()?;
3990                    let mut buffer_start;
3991                    if region.is_main_buffer {
3992                        buffer_start = region.buffer_range.start;
3993                        if query_range.start > region.range.start {
3994                            let overshoot = query_range.start - region.range.start;
3995                            buffer_start.add_assign(&overshoot);
3996                        }
3997                        buffer_start = buffer_start.min(region.buffer_range.end);
3998                    } else {
3999                        buffer_start = cursor.main_buffer_position()?;
4000                    };
4001                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4002                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
4003                        if excerpt.id == end_excerpt_id {
4004                            buffer_end = buffer_end.min(end_buffer_offset);
4005                        }
4006                    }
4007
4008                    if let Some(iterator) =
4009                        get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
4010                    {
4011                        Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
4012                    } else {
4013                        None
4014                    }
4015                };
4016
4017                // Visit each metadata item.
4018                if let Some((metadata_buffer_range, metadata)) =
4019                    metadata_iter.and_then(Iterator::next)
4020                {
4021                    // Find the multibuffer regions that contain the start and end of
4022                    // the metadata item's range.
4023                    if metadata_buffer_range.start > D::default() {
4024                        while let Some(region) = cursor.region() {
4025                            if region.is_main_buffer
4026                                && (region.buffer_range.end >= metadata_buffer_range.start
4027                                    || cursor.is_at_end_of_excerpt())
4028                            {
4029                                break;
4030                            }
4031                            cursor.next();
4032                        }
4033                    }
4034                    let start_region = cursor.region()?;
4035                    while let Some(region) = cursor.region() {
4036                        if region.is_main_buffer
4037                            && (region.buffer_range.end > metadata_buffer_range.end
4038                                || cursor.is_at_end_of_excerpt())
4039                        {
4040                            break;
4041                        }
4042                        cursor.next();
4043                    }
4044                    let end_region = cursor.region();
4045
4046                    // Convert the metadata item's range into multibuffer coordinates.
4047                    let mut start_position = start_region.range.start;
4048                    let region_buffer_start = start_region.buffer_range.start;
4049                    if start_region.is_main_buffer
4050                        && metadata_buffer_range.start > region_buffer_start
4051                    {
4052                        start_position
4053                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4054                        start_position = start_position.min(start_region.range.end);
4055                    }
4056
4057                    let mut end_position = max_position;
4058                    if let Some(end_region) = &end_region {
4059                        end_position = end_region.range.start;
4060                        debug_assert!(end_region.is_main_buffer);
4061                        let region_buffer_start = end_region.buffer_range.start;
4062                        if metadata_buffer_range.end > region_buffer_start {
4063                            end_position
4064                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4065                        }
4066                        end_position = end_position.min(end_region.range.end);
4067                    }
4068
4069                    if start_position <= query_range.end && end_position >= query_range.start {
4070                        return Some((start_position..end_position, metadata, excerpt));
4071                    }
4072                }
4073                // When there are no more metadata items for this excerpt, move to the next excerpt.
4074                else {
4075                    current_excerpt_metadata.take();
4076                    if let Some((end_excerpt_id, _)) = range_end {
4077                        if excerpt.id == end_excerpt_id {
4078                            return None;
4079                        }
4080                    }
4081                    cursor.next_excerpt();
4082                }
4083            }
4084        })
4085    }
4086
4087    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4088        let offset = position.to_offset(self);
4089
4090        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4091        cursor.seek(&DimensionPair {
4092            key: offset,
4093            value: None,
4094        });
4095        cursor.seek_to_start_of_current_excerpt();
4096        let excerpt = cursor.excerpt()?;
4097
4098        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4099        let current_position = self
4100            .anchor_before(offset)
4101            .text_anchor
4102            .to_offset(&excerpt.buffer);
4103        let excerpt_end = excerpt
4104            .buffer
4105            .anchor_before(excerpt_end.min(current_position));
4106
4107        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4108            for hunk in diff.hunks_intersecting_range_rev(
4109                excerpt.range.context.start..excerpt_end,
4110                &excerpt.buffer,
4111            ) {
4112                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4113                if hunk_end >= current_position {
4114                    continue;
4115                }
4116                let start =
4117                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4118                        .to_point(&self);
4119                return Some(MultiBufferRow(start.row));
4120            }
4121        }
4122
4123        loop {
4124            cursor.prev_excerpt();
4125            let excerpt = cursor.excerpt()?;
4126
4127            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4128                continue;
4129            };
4130            let mut hunks =
4131                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4132            let Some(hunk) = hunks.next() else {
4133                continue;
4134            };
4135            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4136                .to_point(&self);
4137            return Some(MultiBufferRow(start.row));
4138        }
4139    }
4140
4141    pub fn has_diff_hunks(&self) -> bool {
4142        self.diffs.values().any(|diff| !diff.is_empty())
4143    }
4144
4145    pub fn surrounding_word<T: ToOffset>(
4146        &self,
4147        start: T,
4148        for_completion: bool,
4149    ) -> (Range<usize>, Option<CharKind>) {
4150        let mut start = start.to_offset(self);
4151        let mut end = start;
4152        let mut next_chars = self.chars_at(start).peekable();
4153        let mut prev_chars = self.reversed_chars_at(start).peekable();
4154
4155        let classifier = self
4156            .char_classifier_at(start)
4157            .for_completion(for_completion);
4158
4159        let word_kind = cmp::max(
4160            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4161            next_chars.peek().copied().map(|c| classifier.kind(c)),
4162        );
4163
4164        for ch in prev_chars {
4165            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4166                start -= ch.len_utf8();
4167            } else {
4168                break;
4169            }
4170        }
4171
4172        for ch in next_chars {
4173            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4174                end += ch.len_utf8();
4175            } else {
4176                break;
4177            }
4178        }
4179
4180        (start..end, word_kind)
4181    }
4182
4183    pub fn is_singleton(&self) -> bool {
4184        self.singleton
4185    }
4186
4187    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4188        if self.singleton {
4189            self.excerpts
4190                .iter()
4191                .next()
4192                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4193        } else {
4194            None
4195        }
4196    }
4197
4198    pub fn len(&self) -> usize {
4199        self.diff_transforms.summary().output.len
4200    }
4201
4202    pub fn is_empty(&self) -> bool {
4203        self.excerpts.summary().text.len == 0
4204    }
4205
4206    pub fn widest_line_number(&self) -> u32 {
4207        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4208        self.excerpts.summary().widest_line_number + 1
4209    }
4210
4211    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
4212        let range = range.start.to_offset(self)..range.end.to_offset(self);
4213        let mut excerpts = self.cursor::<usize>();
4214        excerpts.seek(&range.start);
4215
4216        let mut chunk;
4217        let mut has_trailing_newline;
4218        let excerpt_bytes;
4219        if let Some(region) = excerpts.region() {
4220            let mut bytes = region.buffer.bytes_in_range(
4221                region.buffer_range.start + range.start - region.range.start
4222                    ..(region.buffer_range.start + range.end - region.range.start)
4223                        .min(region.buffer_range.end),
4224            );
4225            chunk = bytes.next().unwrap_or(&[][..]);
4226            excerpt_bytes = Some(bytes);
4227            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4228            if chunk.is_empty() && has_trailing_newline {
4229                chunk = b"\n";
4230                has_trailing_newline = false;
4231            }
4232        } else {
4233            chunk = &[][..];
4234            excerpt_bytes = None;
4235            has_trailing_newline = false;
4236        };
4237
4238        MultiBufferBytes {
4239            range,
4240            cursor: excerpts,
4241            excerpt_bytes,
4242            has_trailing_newline,
4243            chunk,
4244        }
4245    }
4246
4247    pub fn reversed_bytes_in_range<T: ToOffset>(
4248        &self,
4249        range: Range<T>,
4250    ) -> ReversedMultiBufferBytes {
4251        let range = range.start.to_offset(self)..range.end.to_offset(self);
4252        let mut chunks = self.reversed_chunks_in_range(range.clone());
4253        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4254        ReversedMultiBufferBytes {
4255            range,
4256            chunks,
4257            chunk,
4258        }
4259    }
4260
4261    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4262        let mut cursor = self.cursor::<Point>();
4263        cursor.seek(&Point::new(start_row.0, 0));
4264        let mut result = MultiBufferRows {
4265            point: Point::new(0, 0),
4266            is_empty: self.excerpts.is_empty(),
4267            is_singleton: self.is_singleton(),
4268            cursor,
4269        };
4270        result.seek(start_row);
4271        result
4272    }
4273
4274    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4275        let mut chunks = MultiBufferChunks {
4276            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4277            range: 0..0,
4278            excerpts: self.excerpts.cursor(&()),
4279            diff_transforms: self.diff_transforms.cursor(&()),
4280            diffs: &self.diffs,
4281            diff_base_chunks: None,
4282            excerpt_chunks: None,
4283            buffer_chunk: None,
4284            language_aware,
4285        };
4286        let range = range.start.to_offset(self)..range.end.to_offset(self);
4287        chunks.seek(range);
4288        chunks
4289    }
4290
4291    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4292        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4293    }
4294
4295    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4296        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4297    }
4298
4299    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4300        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4301    }
4302
4303    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4304        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4305            buffer.clip_point_utf16(Unclipped(point), bias)
4306        })
4307    }
4308
4309    pub fn offset_to_point(&self, offset: usize) -> Point {
4310        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4311    }
4312
4313    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4314        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4315    }
4316
4317    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4318        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4319    }
4320
4321    pub fn point_to_offset(&self, point: Point) -> usize {
4322        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4323    }
4324
4325    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4326        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4327    }
4328
4329    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4330        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4331    }
4332
4333    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4334        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4335    }
4336
4337    fn clip_dimension<D>(
4338        &self,
4339        position: D,
4340        bias: Bias,
4341        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4342    ) -> D
4343    where
4344        D: TextDimension + Ord + Sub<D, Output = D>,
4345    {
4346        let mut cursor = self.cursor();
4347        cursor.seek(&position);
4348        if let Some(region) = cursor.region() {
4349            if position >= region.range.end {
4350                return region.range.end;
4351            }
4352            let overshoot = position - region.range.start;
4353            let mut buffer_position = region.buffer_range.start;
4354            buffer_position.add_assign(&overshoot);
4355            let clipped_buffer_position =
4356                clip_buffer_position(&region.buffer, buffer_position, bias);
4357            let mut position = region.range.start;
4358            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4359            position
4360        } else {
4361            D::from_text_summary(&self.text_summary())
4362        }
4363    }
4364
4365    fn convert_dimension<D1, D2>(
4366        &self,
4367        key: D1,
4368        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4369    ) -> D2
4370    where
4371        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4372        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4373    {
4374        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4375        cursor.seek(&DimensionPair { key, value: None });
4376        if let Some(region) = cursor.region() {
4377            if key >= region.range.end.key {
4378                return region.range.end.value.unwrap();
4379            }
4380            let start_key = region.range.start.key;
4381            let start_value = region.range.start.value.unwrap();
4382            let buffer_start_key = region.buffer_range.start.key;
4383            let buffer_start_value = region.buffer_range.start.value.unwrap();
4384            let mut buffer_key = buffer_start_key;
4385            buffer_key.add_assign(&(key - start_key));
4386            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4387            let mut result = start_value;
4388            result.add_assign(&(buffer_value - buffer_start_value));
4389            result
4390        } else {
4391            D2::from_text_summary(&self.text_summary())
4392        }
4393    }
4394
4395    pub fn point_to_buffer_offset<T: ToOffset>(
4396        &self,
4397        point: T,
4398    ) -> Option<(&BufferSnapshot, usize)> {
4399        let offset = point.to_offset(self);
4400        let mut cursor = self.cursor::<usize>();
4401        cursor.seek(&offset);
4402        let region = cursor.region()?;
4403        let overshoot = offset - region.range.start;
4404        let buffer_offset = region.buffer_range.start + overshoot;
4405        if buffer_offset == region.buffer.len() + 1
4406            && region.has_trailing_newline
4407            && !region.is_main_buffer
4408        {
4409            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4410        } else if buffer_offset > region.buffer.len() {
4411            return None;
4412        }
4413        Some((region.buffer, buffer_offset))
4414    }
4415
4416    pub fn point_to_buffer_point(
4417        &self,
4418        point: Point,
4419    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4420        let mut cursor = self.cursor::<Point>();
4421        cursor.seek(&point);
4422        let region = cursor.region()?;
4423        let overshoot = point - region.range.start;
4424        let buffer_point = region.buffer_range.start + overshoot;
4425        let excerpt = cursor.excerpt()?;
4426        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4427            && region.has_trailing_newline
4428            && !region.is_main_buffer
4429        {
4430            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4431        } else if buffer_point > region.buffer.max_point() {
4432            return None;
4433        }
4434        Some((region.buffer, buffer_point, excerpt.id))
4435    }
4436
4437    pub fn suggested_indents(
4438        &self,
4439        rows: impl IntoIterator<Item = u32>,
4440        cx: &App,
4441    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4442        let mut result = BTreeMap::new();
4443
4444        let mut rows_for_excerpt = Vec::new();
4445        let mut cursor = self.cursor::<Point>();
4446        let mut rows = rows.into_iter().peekable();
4447        let mut prev_row = u32::MAX;
4448        let mut prev_language_indent_size = IndentSize::default();
4449
4450        while let Some(row) = rows.next() {
4451            cursor.seek(&Point::new(row, 0));
4452            let Some(region) = cursor.region() else {
4453                continue;
4454            };
4455
4456            // Retrieve the language and indent size once for each disjoint region being indented.
4457            let single_indent_size = if row.saturating_sub(1) == prev_row {
4458                prev_language_indent_size
4459            } else {
4460                region
4461                    .buffer
4462                    .language_indent_size_at(Point::new(row, 0), cx)
4463            };
4464            prev_language_indent_size = single_indent_size;
4465            prev_row = row;
4466
4467            let start_buffer_row = region.buffer_range.start.row;
4468            let start_multibuffer_row = region.range.start.row;
4469            let end_multibuffer_row = region.range.end.row;
4470
4471            rows_for_excerpt.push(row);
4472            while let Some(next_row) = rows.peek().copied() {
4473                if end_multibuffer_row > next_row {
4474                    rows_for_excerpt.push(next_row);
4475                    rows.next();
4476                } else {
4477                    break;
4478                }
4479            }
4480
4481            let buffer_rows = rows_for_excerpt
4482                .drain(..)
4483                .map(|row| start_buffer_row + row - start_multibuffer_row);
4484            let buffer_indents = region
4485                .buffer
4486                .suggested_indents(buffer_rows, single_indent_size);
4487            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4488                (
4489                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4490                    indent,
4491                )
4492            });
4493            result.extend(multibuffer_indents);
4494        }
4495
4496        result
4497    }
4498
4499    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4500        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4501            let mut size = buffer.indent_size_for_line(range.start.row);
4502            size.len = size
4503                .len
4504                .min(range.end.column)
4505                .saturating_sub(range.start.column);
4506            size
4507        } else {
4508            IndentSize::spaces(0)
4509        }
4510    }
4511
4512    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4513        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4514            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4515        } else {
4516            LineIndent::spaces(0)
4517        }
4518    }
4519
4520    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4521        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4522
4523        if self.language_settings(cx).extend_comment_on_newline {
4524            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4525                let delimiters = language_scope.line_comment_prefixes();
4526                for delimiter in delimiters {
4527                    if *self
4528                        .chars_at(Point::new(row.0, indent.len() as u32))
4529                        .take(delimiter.chars().count())
4530                        .collect::<String>()
4531                        .as_str()
4532                        == **delimiter
4533                    {
4534                        indent.push_str(&delimiter);
4535                        break;
4536                    }
4537                }
4538            }
4539        }
4540
4541        indent
4542    }
4543
4544    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4545    where
4546        T: ToOffset,
4547    {
4548        for char in self.reversed_chars_at(position) {
4549            if !char.is_whitespace() {
4550                return false;
4551            }
4552            if char == '\n' {
4553                return true;
4554            }
4555        }
4556        return true;
4557    }
4558
4559    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4560        while row.0 > 0 {
4561            row.0 -= 1;
4562            if !self.is_line_blank(row) {
4563                return Some(row);
4564            }
4565        }
4566        None
4567    }
4568
4569    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4570        if let Some((_, range)) = self.buffer_line_for_row(row) {
4571            range.end.column - range.start.column
4572        } else {
4573            0
4574        }
4575    }
4576
4577    pub fn buffer_line_for_row(
4578        &self,
4579        row: MultiBufferRow,
4580    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4581        let mut cursor = self.cursor::<Point>();
4582        let point = Point::new(row.0, 0);
4583        cursor.seek(&point);
4584        let region = cursor.region()?;
4585        let overshoot = point.min(region.range.end) - region.range.start;
4586        let buffer_point = region.buffer_range.start + overshoot;
4587        if buffer_point.row > region.buffer_range.end.row {
4588            return None;
4589        }
4590        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4591        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4592            .min(region.buffer_range.end);
4593        Some((region.buffer, line_start..line_end))
4594    }
4595
4596    pub fn max_point(&self) -> Point {
4597        self.text_summary().lines
4598    }
4599
4600    pub fn max_row(&self) -> MultiBufferRow {
4601        MultiBufferRow(self.text_summary().lines.row)
4602    }
4603
4604    pub fn text_summary(&self) -> TextSummary {
4605        self.diff_transforms.summary().output
4606    }
4607
4608    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4609    where
4610        D: TextDimension,
4611        O: ToOffset,
4612    {
4613        let range = range.start.to_offset(self)..range.end.to_offset(self);
4614        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4615        cursor.seek(&range.start, Bias::Right, &());
4616
4617        let Some(first_transform) = cursor.item() else {
4618            return D::from_text_summary(&TextSummary::default());
4619        };
4620
4621        let diff_transform_start = cursor.start().0;
4622        let diff_transform_end = cursor.end(&()).0;
4623        let diff_start = range.start;
4624        let start_overshoot = diff_start - diff_transform_start;
4625        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4626
4627        let mut result = match first_transform {
4628            DiffTransform::BufferContent { .. } => {
4629                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4630                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4631                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4632            }
4633            DiffTransform::DeletedHunk {
4634                buffer_id,
4635                base_text_byte_range,
4636                has_trailing_newline,
4637                ..
4638            } => {
4639                let buffer_start = base_text_byte_range.start + start_overshoot;
4640                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4641                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4642                    panic!("{:?} is in non-existent deleted hunk", range.start)
4643                };
4644
4645                let include_trailing_newline =
4646                    *has_trailing_newline && range.end >= diff_transform_end;
4647                if include_trailing_newline {
4648                    buffer_end -= 1;
4649                }
4650
4651                let mut summary =
4652                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4653
4654                if include_trailing_newline {
4655                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4656                }
4657
4658                summary
4659            }
4660        };
4661        if range.end < diff_transform_end {
4662            return result;
4663        }
4664
4665        cursor.next(&());
4666        result.add_assign(&D::from_text_summary(&cursor.summary(
4667            &range.end,
4668            Bias::Right,
4669            &(),
4670        )));
4671
4672        let Some(last_transform) = cursor.item() else {
4673            return result;
4674        };
4675
4676        let overshoot = range.end - cursor.start().0;
4677        let suffix = match last_transform {
4678            DiffTransform::BufferContent { .. } => {
4679                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4680                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4681            }
4682            DiffTransform::DeletedHunk {
4683                base_text_byte_range,
4684                buffer_id,
4685                has_trailing_newline,
4686                ..
4687            } => {
4688                let buffer_end = base_text_byte_range.start + overshoot;
4689                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4690                    panic!("{:?} is in non-existent deleted hunk", range.end)
4691                };
4692
4693                let mut suffix = base_text
4694                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4695                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4696                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4697                }
4698                suffix
4699            }
4700        };
4701
4702        result.add_assign(&suffix);
4703        result
4704    }
4705
4706    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4707    where
4708        D: TextDimension,
4709    {
4710        // let mut range = range.start..range.end;
4711        let mut summary = D::zero(&());
4712        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4713        cursor.seek(&range.start, Bias::Right, &());
4714        if let Some(excerpt) = cursor.item() {
4715            let mut end_before_newline = cursor.end(&());
4716            if excerpt.has_trailing_newline {
4717                end_before_newline -= ExcerptOffset::new(1);
4718            }
4719
4720            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4721            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4722            let end_in_excerpt =
4723                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4724            summary.add_assign(
4725                &excerpt
4726                    .buffer
4727                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4728            );
4729
4730            if range.end > end_before_newline {
4731                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4732            }
4733
4734            cursor.next(&());
4735        }
4736
4737        if range.end > *cursor.start() {
4738            summary.add_assign(
4739                &cursor
4740                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4741                    .0,
4742            );
4743            if let Some(excerpt) = cursor.item() {
4744                range.end = cmp::max(*cursor.start(), range.end);
4745
4746                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4747                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4748                summary.add_assign(
4749                    &excerpt
4750                        .buffer
4751                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4752                );
4753            }
4754        }
4755
4756        summary
4757    }
4758
4759    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4760    where
4761        D: TextDimension + Ord + Sub<D, Output = D>,
4762    {
4763        self.summaries_for_anchors([anchor])[0]
4764    }
4765
4766    fn resolve_summary_for_anchor<D>(
4767        &self,
4768        anchor: &Anchor,
4769        excerpt_position: D,
4770        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4771    ) -> D
4772    where
4773        D: TextDimension + Ord + Sub<D, Output = D>,
4774    {
4775        loop {
4776            let transform_end_position = diff_transforms.end(&()).0.0;
4777            let at_transform_end =
4778                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4779            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4780                diff_transforms.next(&());
4781                continue;
4782            }
4783
4784            let mut position = diff_transforms.start().1.0;
4785            match diff_transforms.item() {
4786                Some(DiffTransform::DeletedHunk {
4787                    buffer_id,
4788                    base_text_byte_range,
4789                    ..
4790                }) => {
4791                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4792                        if let Some(base_text) =
4793                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4794                        {
4795                            if base_text.can_resolve(&diff_base_anchor) {
4796                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4797                                if base_text_offset >= base_text_byte_range.start
4798                                    && base_text_offset <= base_text_byte_range.end
4799                                {
4800                                    let position_in_hunk = base_text
4801                                        .text_summary_for_range::<D, _>(
4802                                            base_text_byte_range.start..base_text_offset,
4803                                        );
4804                                    position.add_assign(&position_in_hunk);
4805                                } else if at_transform_end {
4806                                    diff_transforms.next(&());
4807                                    continue;
4808                                }
4809                            }
4810                        }
4811                    }
4812                }
4813                _ => {
4814                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4815                        diff_transforms.next(&());
4816                        continue;
4817                    }
4818                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4819                    position.add_assign(&overshoot);
4820                }
4821            }
4822
4823            return position;
4824        }
4825    }
4826
4827    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4828        let mut cursor = self
4829            .excerpts
4830            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4831        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4832
4833        cursor.seek(&Some(locator), Bias::Left, &());
4834        if cursor.item().is_none() {
4835            cursor.next(&());
4836        }
4837
4838        let mut position = cursor.start().1;
4839        if let Some(excerpt) = cursor.item() {
4840            if excerpt.id == anchor.excerpt_id {
4841                let excerpt_buffer_start = excerpt
4842                    .buffer
4843                    .offset_for_anchor(&excerpt.range.context.start);
4844                let excerpt_buffer_end =
4845                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4846                let buffer_position = cmp::min(
4847                    excerpt_buffer_end,
4848                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4849                );
4850                if buffer_position > excerpt_buffer_start {
4851                    position.value += buffer_position - excerpt_buffer_start;
4852                }
4853            }
4854        }
4855        position
4856    }
4857
4858    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4859        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4860            excerpt_id = *replacement;
4861        }
4862        return excerpt_id;
4863    }
4864
4865    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4866    where
4867        D: TextDimension + Ord + Sub<D, Output = D>,
4868        I: 'a + IntoIterator<Item = &'a Anchor>,
4869    {
4870        let mut anchors = anchors.into_iter().peekable();
4871        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4872        let mut diff_transforms_cursor = self
4873            .diff_transforms
4874            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4875        diff_transforms_cursor.next(&());
4876
4877        let mut summaries = Vec::new();
4878        while let Some(anchor) = anchors.peek() {
4879            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4880            let excerpt_anchors = iter::from_fn(|| {
4881                let anchor = anchors.peek()?;
4882                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4883                    Some(anchors.next().unwrap())
4884                } else {
4885                    None
4886                }
4887            });
4888
4889            let locator = self.excerpt_locator_for_id(excerpt_id);
4890            cursor.seek_forward(locator, Bias::Left, &());
4891            if cursor.item().is_none() {
4892                cursor.next(&());
4893            }
4894
4895            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4896            if let Some(excerpt) = cursor.item() {
4897                if excerpt.id != excerpt_id {
4898                    let position = self.resolve_summary_for_anchor(
4899                        &Anchor::min(),
4900                        excerpt_start_position,
4901                        &mut diff_transforms_cursor,
4902                    );
4903                    summaries.extend(excerpt_anchors.map(|_| position));
4904                    continue;
4905                }
4906                let excerpt_buffer_start =
4907                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4908                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4909                for (buffer_summary, anchor) in excerpt
4910                    .buffer
4911                    .summaries_for_anchors_with_payload::<D, _, _>(
4912                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4913                    )
4914                {
4915                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4916                    let mut position = excerpt_start_position;
4917                    if summary > excerpt_buffer_start {
4918                        position.add_assign(&(summary - excerpt_buffer_start));
4919                    }
4920
4921                    if position > diff_transforms_cursor.start().0.0 {
4922                        diff_transforms_cursor.seek_forward(
4923                            &ExcerptDimension(position),
4924                            Bias::Left,
4925                            &(),
4926                        );
4927                    }
4928
4929                    summaries.push(self.resolve_summary_for_anchor(
4930                        anchor,
4931                        position,
4932                        &mut diff_transforms_cursor,
4933                    ));
4934                }
4935            } else {
4936                diff_transforms_cursor.seek_forward(
4937                    &ExcerptDimension(excerpt_start_position),
4938                    Bias::Left,
4939                    &(),
4940                );
4941                let position = self.resolve_summary_for_anchor(
4942                    &Anchor::max(),
4943                    excerpt_start_position,
4944                    &mut diff_transforms_cursor,
4945                );
4946                summaries.extend(excerpt_anchors.map(|_| position));
4947            }
4948        }
4949
4950        summaries
4951    }
4952
4953    pub fn dimensions_from_points<'a, D>(
4954        &'a self,
4955        points: impl 'a + IntoIterator<Item = Point>,
4956    ) -> impl 'a + Iterator<Item = D>
4957    where
4958        D: TextDimension + Sub<D, Output = D>,
4959    {
4960        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4961        cursor.seek(&DimensionPair {
4962            key: Point::default(),
4963            value: None,
4964        });
4965        let mut points = points.into_iter();
4966        iter::from_fn(move || {
4967            let point = points.next()?;
4968
4969            cursor.seek_forward(&DimensionPair {
4970                key: point,
4971                value: None,
4972            });
4973
4974            if let Some(region) = cursor.region() {
4975                let overshoot = point - region.range.start.key;
4976                let buffer_point = region.buffer_range.start.key + overshoot;
4977                let mut position = region.range.start.value.unwrap();
4978                position.add_assign(
4979                    &region
4980                        .buffer
4981                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4982                );
4983                if point == region.range.end.key && region.has_trailing_newline {
4984                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4985                }
4986                return Some(position);
4987            } else {
4988                return Some(D::from_text_summary(&self.text_summary()));
4989            }
4990        })
4991    }
4992
4993    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4994    where
4995        I: 'a + IntoIterator<Item = &'a Anchor>,
4996    {
4997        let mut anchors = anchors.into_iter().enumerate().peekable();
4998        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4999        cursor.next(&());
5000
5001        let mut result = Vec::new();
5002
5003        while let Some((_, anchor)) = anchors.peek() {
5004            let old_excerpt_id = anchor.excerpt_id;
5005
5006            // Find the location where this anchor's excerpt should be.
5007            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5008            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
5009
5010            if cursor.item().is_none() {
5011                cursor.next(&());
5012            }
5013
5014            let next_excerpt = cursor.item();
5015            let prev_excerpt = cursor.prev_item();
5016
5017            // Process all of the anchors for this excerpt.
5018            while let Some((_, anchor)) = anchors.peek() {
5019                if anchor.excerpt_id != old_excerpt_id {
5020                    break;
5021                }
5022                let (anchor_ix, anchor) = anchors.next().unwrap();
5023                let mut anchor = *anchor;
5024
5025                // Leave min and max anchors unchanged if invalid or
5026                // if the old excerpt still exists at this location
5027                let mut kept_position = next_excerpt
5028                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
5029                    || old_excerpt_id == ExcerptId::max()
5030                    || old_excerpt_id == ExcerptId::min();
5031
5032                // If the old excerpt no longer exists at this location, then attempt to
5033                // find an equivalent position for this anchor in an adjacent excerpt.
5034                if !kept_position {
5035                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5036                        if excerpt.contains(&anchor) {
5037                            anchor.excerpt_id = excerpt.id;
5038                            kept_position = true;
5039                            break;
5040                        }
5041                    }
5042                }
5043
5044                // If there's no adjacent excerpt that contains the anchor's position,
5045                // then report that the anchor has lost its position.
5046                if !kept_position {
5047                    anchor = if let Some(excerpt) = next_excerpt {
5048                        let mut text_anchor = excerpt
5049                            .range
5050                            .context
5051                            .start
5052                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5053                        if text_anchor
5054                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5055                            .is_gt()
5056                        {
5057                            text_anchor = excerpt.range.context.end;
5058                        }
5059                        Anchor {
5060                            buffer_id: Some(excerpt.buffer_id),
5061                            excerpt_id: excerpt.id,
5062                            text_anchor,
5063                            diff_base_anchor: None,
5064                        }
5065                    } else if let Some(excerpt) = prev_excerpt {
5066                        let mut text_anchor = excerpt
5067                            .range
5068                            .context
5069                            .end
5070                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5071                        if text_anchor
5072                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5073                            .is_lt()
5074                        {
5075                            text_anchor = excerpt.range.context.start;
5076                        }
5077                        Anchor {
5078                            buffer_id: Some(excerpt.buffer_id),
5079                            excerpt_id: excerpt.id,
5080                            text_anchor,
5081                            diff_base_anchor: None,
5082                        }
5083                    } else if anchor.text_anchor.bias == Bias::Left {
5084                        Anchor::min()
5085                    } else {
5086                        Anchor::max()
5087                    };
5088                }
5089
5090                result.push((anchor_ix, anchor, kept_position));
5091            }
5092        }
5093        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5094        result
5095    }
5096
5097    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5098        self.anchor_at(position, Bias::Left)
5099    }
5100
5101    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5102        self.anchor_at(position, Bias::Right)
5103    }
5104
5105    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5106        let offset = position.to_offset(self);
5107
5108        // Find the given position in the diff transforms. Determine the corresponding
5109        // offset in the excerpts, and whether the position is within a deleted hunk.
5110        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
5111        diff_transforms.seek(&offset, Bias::Right, &());
5112
5113        if offset == diff_transforms.start().0 && bias == Bias::Left {
5114            if let Some(prev_item) = diff_transforms.prev_item() {
5115                match prev_item {
5116                    DiffTransform::DeletedHunk { .. } => {
5117                        diff_transforms.prev(&());
5118                    }
5119                    _ => {}
5120                }
5121            }
5122        }
5123        let offset_in_transform = offset - diff_transforms.start().0;
5124        let mut excerpt_offset = diff_transforms.start().1;
5125        let mut diff_base_anchor = None;
5126        if let Some(DiffTransform::DeletedHunk {
5127            buffer_id,
5128            base_text_byte_range,
5129            has_trailing_newline,
5130            ..
5131        }) = diff_transforms.item()
5132        {
5133            let diff = self.diffs.get(buffer_id).expect("missing diff");
5134            if offset_in_transform > base_text_byte_range.len() {
5135                debug_assert!(*has_trailing_newline);
5136                bias = Bias::Right;
5137            } else {
5138                diff_base_anchor = Some(
5139                    diff.base_text()
5140                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5141                );
5142                bias = Bias::Left;
5143            }
5144        } else {
5145            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5146        };
5147
5148        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5149            return Anchor {
5150                buffer_id: Some(buffer_id),
5151                excerpt_id: *excerpt_id,
5152                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5153                diff_base_anchor,
5154            };
5155        }
5156
5157        let mut excerpts = self
5158            .excerpts
5159            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5160        excerpts.seek(&excerpt_offset, Bias::Right, &());
5161        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5162            excerpts.prev(&());
5163        }
5164        if let Some(excerpt) = excerpts.item() {
5165            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5166            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5167                overshoot -= 1;
5168                bias = Bias::Right;
5169            }
5170
5171            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5172            let text_anchor =
5173                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5174            Anchor {
5175                buffer_id: Some(excerpt.buffer_id),
5176                excerpt_id: excerpt.id,
5177                text_anchor,
5178                diff_base_anchor,
5179            }
5180        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5181            Anchor::min()
5182        } else {
5183            Anchor::max()
5184        }
5185    }
5186
5187    /// Returns an anchor for the given excerpt and text anchor,
5188    /// returns None if the excerpt_id is no longer valid.
5189    pub fn anchor_in_excerpt(
5190        &self,
5191        excerpt_id: ExcerptId,
5192        text_anchor: text::Anchor,
5193    ) -> Option<Anchor> {
5194        let locator = self.excerpt_locator_for_id(excerpt_id);
5195        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5196        cursor.seek(locator, Bias::Left, &());
5197        if let Some(excerpt) = cursor.item() {
5198            if excerpt.id == excerpt_id {
5199                let text_anchor = excerpt.clip_anchor(text_anchor);
5200                drop(cursor);
5201                return Some(Anchor {
5202                    buffer_id: Some(excerpt.buffer_id),
5203                    excerpt_id,
5204                    text_anchor,
5205                    diff_base_anchor: None,
5206                });
5207            }
5208        }
5209        None
5210    }
5211
5212    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5213        Some(self.excerpt(excerpt_id)?.range.context.clone())
5214    }
5215
5216    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5217        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5218            true
5219        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5220            excerpt.buffer.can_resolve(&anchor.text_anchor)
5221        } else {
5222            false
5223        }
5224    }
5225
5226    pub fn excerpts(
5227        &self,
5228    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5229        self.excerpts
5230            .iter()
5231            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5232    }
5233
5234    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
5235        let excerpts = self.excerpts.cursor(&());
5236        let diff_transforms = self.diff_transforms.cursor(&());
5237        MultiBufferCursor {
5238            excerpts,
5239            diff_transforms,
5240            diffs: &self.diffs,
5241            cached_region: None,
5242        }
5243    }
5244
5245    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5246        let start_locator = self.excerpt_locator_for_id(id);
5247        let mut excerpts = self
5248            .excerpts
5249            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5250        excerpts.seek(&Some(start_locator), Bias::Left, &());
5251        excerpts.prev(&());
5252
5253        let mut diff_transforms = self
5254            .diff_transforms
5255            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5256        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5257        if diff_transforms.end(&()).1 < excerpts.start().1 {
5258            diff_transforms.next(&());
5259        }
5260
5261        let excerpt = excerpts.item()?;
5262        Some(MultiBufferExcerpt {
5263            excerpt,
5264            offset: diff_transforms.start().0.0,
5265            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5266            excerpt_offset: excerpts.start().1.clone(),
5267            diff_transforms,
5268        })
5269    }
5270
5271    pub fn excerpt_boundaries_in_range<R, T>(
5272        &self,
5273        range: R,
5274    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5275    where
5276        R: RangeBounds<T>,
5277        T: ToOffset,
5278    {
5279        let start_offset;
5280        let start = match range.start_bound() {
5281            Bound::Included(start) => {
5282                start_offset = start.to_offset(self);
5283                Bound::Included(start_offset)
5284            }
5285            Bound::Excluded(_) => {
5286                panic!("not supported")
5287            }
5288            Bound::Unbounded => {
5289                start_offset = 0;
5290                Bound::Unbounded
5291            }
5292        };
5293        let end = match range.end_bound() {
5294            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5295            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5296            Bound::Unbounded => Bound::Unbounded,
5297        };
5298        let bounds = (start, end);
5299
5300        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5301        cursor.seek(&DimensionPair {
5302            key: start_offset,
5303            value: None,
5304        });
5305
5306        if cursor
5307            .region()
5308            .is_some_and(|region| bounds.contains(&region.range.start.key))
5309        {
5310            cursor.prev_excerpt();
5311        } else {
5312            cursor.seek_to_start_of_current_excerpt();
5313        }
5314        let mut prev_region = cursor.region();
5315
5316        cursor.next_excerpt();
5317
5318        iter::from_fn(move || {
5319            loop {
5320                if self.singleton {
5321                    return None;
5322                }
5323
5324                let next_region = cursor.region()?;
5325                cursor.next_excerpt();
5326                if !bounds.contains(&next_region.range.start.key) {
5327                    prev_region = Some(next_region);
5328                    continue;
5329                }
5330
5331                let next_region_start = next_region.range.start.value.unwrap();
5332                let next_region_end = if let Some(region) = cursor.region() {
5333                    region.range.start.value.unwrap()
5334                } else {
5335                    self.max_point()
5336                };
5337
5338                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5339                    id: region.excerpt.id,
5340                    buffer: region.excerpt.buffer.clone(),
5341                    buffer_id: region.excerpt.buffer_id,
5342                    range: region.excerpt.range.clone(),
5343                    end_row: MultiBufferRow(next_region_start.row),
5344                });
5345
5346                let next = ExcerptInfo {
5347                    id: next_region.excerpt.id,
5348                    buffer: next_region.excerpt.buffer.clone(),
5349                    buffer_id: next_region.excerpt.buffer_id,
5350                    range: next_region.excerpt.range.clone(),
5351                    end_row: if next_region.excerpt.has_trailing_newline {
5352                        MultiBufferRow(next_region_end.row - 1)
5353                    } else {
5354                        MultiBufferRow(next_region_end.row)
5355                    },
5356                };
5357
5358                let row = MultiBufferRow(next_region_start.row);
5359
5360                prev_region = Some(next_region);
5361
5362                return Some(ExcerptBoundary { row, prev, next });
5363            }
5364        })
5365    }
5366
5367    pub fn edit_count(&self) -> usize {
5368        self.edit_count
5369    }
5370
5371    pub fn non_text_state_update_count(&self) -> usize {
5372        self.non_text_state_update_count
5373    }
5374
5375    /// Returns the smallest enclosing bracket ranges containing the given range or
5376    /// None if no brackets contain range or the range is not contained in a single
5377    /// excerpt
5378    ///
5379    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5380    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5381        &self,
5382        range: Range<T>,
5383        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5384    ) -> Option<(Range<usize>, Range<usize>)> {
5385        let range = range.start.to_offset(self)..range.end.to_offset(self);
5386        let mut excerpt = self.excerpt_containing(range.clone())?;
5387        let buffer = excerpt.buffer();
5388        let excerpt_buffer_range = excerpt.buffer_range();
5389
5390        // Filter to ranges contained in the excerpt
5391        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5392            excerpt_buffer_range.contains(&open.start)
5393                && excerpt_buffer_range.contains(&close.end)
5394                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5395        };
5396
5397        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5398            excerpt.map_range_to_buffer(range),
5399            Some(&range_filter),
5400        )?;
5401
5402        Some((
5403            excerpt.map_range_from_buffer(open),
5404            excerpt.map_range_from_buffer(close),
5405        ))
5406    }
5407
5408    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5409    /// not contained in a single excerpt
5410    pub fn enclosing_bracket_ranges<T: ToOffset>(
5411        &self,
5412        range: Range<T>,
5413    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5414        let range = range.start.to_offset(self)..range.end.to_offset(self);
5415        let mut excerpt = self.excerpt_containing(range.clone())?;
5416
5417        Some(
5418            excerpt
5419                .buffer()
5420                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5421                .filter_map(move |pair| {
5422                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5423                        Some((
5424                            excerpt.map_range_from_buffer(pair.open_range),
5425                            excerpt.map_range_from_buffer(pair.close_range),
5426                        ))
5427                    } else {
5428                        None
5429                    }
5430                }),
5431        )
5432    }
5433
5434    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5435    /// not contained in a single excerpt
5436    pub fn text_object_ranges<T: ToOffset>(
5437        &self,
5438        range: Range<T>,
5439        options: TreeSitterOptions,
5440    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5441        let range = range.start.to_offset(self)..range.end.to_offset(self);
5442        self.excerpt_containing(range.clone())
5443            .map(|mut excerpt| {
5444                excerpt
5445                    .buffer()
5446                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5447                    .filter_map(move |(range, text_object)| {
5448                        if excerpt.contains_buffer_range(range.clone()) {
5449                            Some((excerpt.map_range_from_buffer(range), text_object))
5450                        } else {
5451                            None
5452                        }
5453                    })
5454            })
5455            .into_iter()
5456            .flatten()
5457    }
5458
5459    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5460    /// not contained in a single excerpt
5461    pub fn bracket_ranges<T: ToOffset>(
5462        &self,
5463        range: Range<T>,
5464    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5465        let range = range.start.to_offset(self)..range.end.to_offset(self);
5466        let mut excerpt = self.excerpt_containing(range.clone())?;
5467
5468        Some(
5469            excerpt
5470                .buffer()
5471                .bracket_ranges(excerpt.map_range_to_buffer(range))
5472                .filter_map(move |pair| {
5473                    let buffer_range = pair.open_range.start..pair.close_range.end;
5474                    if excerpt.contains_buffer_range(buffer_range) {
5475                        Some((
5476                            excerpt.map_range_from_buffer(pair.open_range),
5477                            excerpt.map_range_from_buffer(pair.close_range),
5478                        ))
5479                    } else {
5480                        None
5481                    }
5482                }),
5483        )
5484    }
5485
5486    pub fn redacted_ranges<'a, T: ToOffset>(
5487        &'a self,
5488        range: Range<T>,
5489        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5490    ) -> impl Iterator<Item = Range<usize>> + 'a {
5491        let range = range.start.to_offset(self)..range.end.to_offset(self);
5492        self.lift_buffer_metadata(range, move |buffer, range| {
5493            if redaction_enabled(buffer.file()) {
5494                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5495            } else {
5496                None
5497            }
5498        })
5499        .map(|(range, _, _)| range)
5500    }
5501
5502    pub fn runnable_ranges(
5503        &self,
5504        range: Range<Anchor>,
5505    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5506        let range = range.start.to_offset(self)..range.end.to_offset(self);
5507        self.lift_buffer_metadata(range, move |buffer, range| {
5508            Some(
5509                buffer
5510                    .runnable_ranges(range.clone())
5511                    .filter(move |runnable| {
5512                        runnable.run_range.start >= range.start
5513                            && runnable.run_range.end < range.end
5514                    })
5515                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5516            )
5517        })
5518        .map(|(run_range, runnable, _)| language::RunnableRange {
5519            run_range,
5520            ..runnable
5521        })
5522    }
5523
5524    pub fn line_indents(
5525        &self,
5526        start_row: MultiBufferRow,
5527        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5528    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5529        let max_point = self.max_point();
5530        let mut cursor = self.cursor::<Point>();
5531        cursor.seek(&Point::new(start_row.0, 0));
5532        iter::from_fn(move || {
5533            let mut region = cursor.region()?;
5534            while !buffer_filter(&region.excerpt.buffer) {
5535                cursor.next();
5536                region = cursor.region()?;
5537            }
5538            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5539            let buffer_start_row =
5540                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5541
5542            let buffer_end_row = if region.is_main_buffer
5543                && (region.has_trailing_newline || region.range.end == max_point)
5544            {
5545                region.buffer_range.end.row
5546            } else {
5547                region.buffer_range.end.row.saturating_sub(1)
5548            };
5549
5550            let line_indents = region
5551                .buffer
5552                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5553            cursor.next();
5554            return Some(line_indents.map(move |(buffer_row, indent)| {
5555                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5556                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5557            }));
5558        })
5559        .flatten()
5560    }
5561
5562    pub fn reversed_line_indents(
5563        &self,
5564        end_row: MultiBufferRow,
5565        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5566    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5567        let max_point = self.max_point();
5568        let mut cursor = self.cursor::<Point>();
5569        cursor.seek(&Point::new(end_row.0, 0));
5570        iter::from_fn(move || {
5571            let mut region = cursor.region()?;
5572            while !buffer_filter(&region.excerpt.buffer) {
5573                cursor.prev();
5574                region = cursor.region()?;
5575            }
5576
5577            let buffer_start_row = region.buffer_range.start.row;
5578            let buffer_end_row = if region.is_main_buffer
5579                && (region.has_trailing_newline || region.range.end == max_point)
5580            {
5581                region.buffer_range.end.row + 1
5582            } else {
5583                region.buffer_range.end.row
5584            };
5585
5586            let overshoot = end_row.0 - region.range.start.row;
5587            let buffer_end_row =
5588                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5589
5590            let line_indents = region
5591                .buffer
5592                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5593            cursor.prev();
5594            return Some(line_indents.map(move |(buffer_row, indent)| {
5595                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5596                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5597            }));
5598        })
5599        .flatten()
5600    }
5601
5602    pub async fn enclosing_indent(
5603        &self,
5604        mut target_row: MultiBufferRow,
5605    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5606        let max_row = MultiBufferRow(self.max_point().row);
5607        if target_row >= max_row {
5608            return None;
5609        }
5610
5611        let mut target_indent = self.line_indent_for_row(target_row);
5612
5613        // If the current row is at the start of an indented block, we want to return this
5614        // block as the enclosing indent.
5615        if !target_indent.is_line_empty() && target_row < max_row {
5616            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5617            if !next_line_indent.is_line_empty()
5618                && target_indent.raw_len() < next_line_indent.raw_len()
5619            {
5620                target_indent = next_line_indent;
5621                target_row.0 += 1;
5622            }
5623        }
5624
5625        const SEARCH_ROW_LIMIT: u32 = 25000;
5626        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5627        const YIELD_INTERVAL: u32 = 100;
5628
5629        let mut accessed_row_counter = 0;
5630
5631        // If there is a blank line at the current row, search for the next non indented lines
5632        if target_indent.is_line_empty() {
5633            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5634            let end =
5635                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5636
5637            let mut non_empty_line_above = None;
5638            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5639                if row < start {
5640                    break;
5641                }
5642                accessed_row_counter += 1;
5643                if accessed_row_counter == YIELD_INTERVAL {
5644                    accessed_row_counter = 0;
5645                    yield_now().await;
5646                }
5647                if !indent.is_line_empty() {
5648                    non_empty_line_above = Some((row, indent));
5649                    break;
5650                }
5651            }
5652
5653            let mut non_empty_line_below = None;
5654            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5655                if row > end {
5656                    break;
5657                }
5658                accessed_row_counter += 1;
5659                if accessed_row_counter == YIELD_INTERVAL {
5660                    accessed_row_counter = 0;
5661                    yield_now().await;
5662                }
5663                if !indent.is_line_empty() {
5664                    non_empty_line_below = Some((row, indent));
5665                    break;
5666                }
5667            }
5668
5669            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5670                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5671                    if above_indent.raw_len() >= below_indent.raw_len() {
5672                        (above_row, above_indent)
5673                    } else {
5674                        (below_row, below_indent)
5675                    }
5676                }
5677                (Some(above), None) => above,
5678                (None, Some(below)) => below,
5679                _ => return None,
5680            };
5681
5682            target_indent = indent;
5683            target_row = row;
5684        }
5685
5686        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5687        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5688
5689        let mut start_indent = None;
5690        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5691            if row < start {
5692                break;
5693            }
5694            accessed_row_counter += 1;
5695            if accessed_row_counter == YIELD_INTERVAL {
5696                accessed_row_counter = 0;
5697                yield_now().await;
5698            }
5699            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5700                start_indent = Some((row, indent));
5701                break;
5702            }
5703        }
5704        let (start_row, start_indent_size) = start_indent?;
5705
5706        let mut end_indent = (end, None);
5707        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5708            if row > end {
5709                break;
5710            }
5711            accessed_row_counter += 1;
5712            if accessed_row_counter == YIELD_INTERVAL {
5713                accessed_row_counter = 0;
5714                yield_now().await;
5715            }
5716            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5717                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5718                break;
5719            }
5720        }
5721        let (end_row, end_indent_size) = end_indent;
5722
5723        let indent = if let Some(end_indent_size) = end_indent_size {
5724            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5725                start_indent_size
5726            } else {
5727                end_indent_size
5728            }
5729        } else {
5730            start_indent_size
5731        };
5732
5733        Some((start_row..end_row, indent))
5734    }
5735
5736    pub fn indent_guides_in_range<T: ToPoint>(
5737        &self,
5738        range: Range<T>,
5739        ignore_disabled_for_language: bool,
5740        cx: &App,
5741    ) -> impl Iterator<Item = IndentGuide> {
5742        let range = range.start.to_point(self)..range.end.to_point(self);
5743        let start_row = MultiBufferRow(range.start.row);
5744        let end_row = MultiBufferRow(range.end.row);
5745
5746        let mut row_indents = self.line_indents(start_row, |buffer| {
5747            let settings =
5748                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5749            settings.indent_guides.enabled || ignore_disabled_for_language
5750        });
5751
5752        let mut result = Vec::new();
5753        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5754
5755        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5756            if first_row > end_row {
5757                break;
5758            }
5759            let current_depth = indent_stack.len() as u32;
5760
5761            let settings =
5762                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5763            let tab_size = settings.tab_size.get() as u32;
5764
5765            // When encountering empty, continue until found useful line indent
5766            // then add to the indent stack with the depth found
5767            let mut found_indent = false;
5768            let mut last_row = first_row;
5769            if line_indent.is_line_empty() {
5770                while !found_indent {
5771                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5772                        break;
5773                    };
5774                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5775                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5776                        break;
5777                    }
5778
5779                    if new_line_indent.is_line_empty() {
5780                        continue;
5781                    }
5782                    last_row = target_row.min(end_row);
5783                    line_indent = new_line_indent;
5784                    found_indent = true;
5785                    break;
5786                }
5787            } else {
5788                found_indent = true
5789            }
5790
5791            let depth = if found_indent {
5792                line_indent.len(tab_size) / tab_size
5793                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5794            } else {
5795                current_depth
5796            };
5797
5798            match depth.cmp(&current_depth) {
5799                cmp::Ordering::Less => {
5800                    for _ in 0..(current_depth - depth) {
5801                        let mut indent = indent_stack.pop().unwrap();
5802                        if last_row != first_row {
5803                            // In this case, we landed on an empty row, had to seek forward,
5804                            // and discovered that the indent we where on is ending.
5805                            // This means that the last display row must
5806                            // be on line that ends this indent range, so we
5807                            // should display the range up to the first non-empty line
5808                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5809                        }
5810
5811                        result.push(indent)
5812                    }
5813                }
5814                cmp::Ordering::Greater => {
5815                    for next_depth in current_depth..depth {
5816                        indent_stack.push(IndentGuide {
5817                            buffer_id: buffer.remote_id(),
5818                            start_row: first_row,
5819                            end_row: last_row,
5820                            depth: next_depth,
5821                            tab_size,
5822                            settings: settings.indent_guides,
5823                        });
5824                    }
5825                }
5826                _ => {}
5827            }
5828
5829            for indent in indent_stack.iter_mut() {
5830                indent.end_row = last_row;
5831            }
5832        }
5833
5834        result.extend(indent_stack);
5835        result.into_iter()
5836    }
5837
5838    pub fn trailing_excerpt_update_count(&self) -> usize {
5839        self.trailing_excerpt_update_count
5840    }
5841
5842    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5843        self.point_to_buffer_offset(point)
5844            .and_then(|(buffer, _)| buffer.file())
5845    }
5846
5847    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5848        self.point_to_buffer_offset(point)
5849            .and_then(|(buffer, offset)| buffer.language_at(offset))
5850    }
5851
5852    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5853        self.excerpts
5854            .first()
5855            .map(|excerpt| &excerpt.buffer)
5856            .map(|buffer| {
5857                language_settings(
5858                    buffer.language().map(|language| language.name()),
5859                    buffer.file(),
5860                    cx,
5861                )
5862            })
5863            .unwrap_or_else(move || self.language_settings_at(0, cx))
5864    }
5865
5866    pub fn language_settings_at<'a, T: ToOffset>(
5867        &'a self,
5868        point: T,
5869        cx: &'a App,
5870    ) -> Cow<'a, LanguageSettings> {
5871        let mut language = None;
5872        let mut file = None;
5873        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5874            language = buffer.language_at(offset);
5875            file = buffer.file();
5876        }
5877        language_settings(language.map(|l| l.name()), file, cx)
5878    }
5879
5880    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5881        self.point_to_buffer_offset(point)
5882            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5883    }
5884
5885    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5886        self.point_to_buffer_offset(point)
5887            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5888            .unwrap_or_default()
5889    }
5890
5891    pub fn language_indent_size_at<T: ToOffset>(
5892        &self,
5893        position: T,
5894        cx: &App,
5895    ) -> Option<IndentSize> {
5896        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5897        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5898    }
5899
5900    pub fn is_dirty(&self) -> bool {
5901        self.is_dirty
5902    }
5903
5904    pub fn has_deleted_file(&self) -> bool {
5905        self.has_deleted_file
5906    }
5907
5908    pub fn has_conflict(&self) -> bool {
5909        self.has_conflict
5910    }
5911
5912    pub fn has_diagnostics(&self) -> bool {
5913        self.excerpts
5914            .iter()
5915            .any(|excerpt| excerpt.buffer.has_diagnostics())
5916    }
5917
5918    pub fn diagnostic_group(
5919        &self,
5920        buffer_id: BufferId,
5921        group_id: usize,
5922    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5923        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5924            if buffer.remote_id() != buffer_id {
5925                return None;
5926            };
5927            Some(
5928                buffer
5929                    .diagnostic_group(group_id)
5930                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5931            )
5932        })
5933        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5934    }
5935
5936    pub fn diagnostics_in_range<'a, T>(
5937        &'a self,
5938        range: Range<T>,
5939    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5940    where
5941        T: 'a
5942            + text::ToOffset
5943            + text::FromAnchor
5944            + TextDimension
5945            + Ord
5946            + Sub<T, Output = T>
5947            + fmt::Debug,
5948    {
5949        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5950            Some(
5951                buffer
5952                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5953                    .map(|entry| (entry.range, entry.diagnostic)),
5954            )
5955        })
5956        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5957    }
5958
5959    pub fn syntax_ancestor<T: ToOffset>(
5960        &self,
5961        range: Range<T>,
5962    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5963        let range = range.start.to_offset(self)..range.end.to_offset(self);
5964        let mut excerpt = self.excerpt_containing(range.clone())?;
5965        let node = excerpt
5966            .buffer()
5967            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5968        let node_range = node.byte_range();
5969        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5970            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5971        } else {
5972            MultiOrSingleBufferOffsetRange::Single(node_range)
5973        };
5974        Some((node, range))
5975    }
5976
5977    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5978        let (excerpt_id, _, buffer) = self.as_singleton()?;
5979        let outline = buffer.outline(theme)?;
5980        Some(Outline::new(
5981            outline
5982                .items
5983                .into_iter()
5984                .flat_map(|item| {
5985                    Some(OutlineItem {
5986                        depth: item.depth,
5987                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5988                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5989                        text: item.text,
5990                        highlight_ranges: item.highlight_ranges,
5991                        name_ranges: item.name_ranges,
5992                        body_range: item.body_range.and_then(|body_range| {
5993                            Some(
5994                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5995                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5996                            )
5997                        }),
5998                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5999                            Some(
6000                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6001                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6002                            )
6003                        }),
6004                    })
6005                })
6006                .collect(),
6007        ))
6008    }
6009
6010    pub fn symbols_containing<T: ToOffset>(
6011        &self,
6012        offset: T,
6013        theme: Option<&SyntaxTheme>,
6014    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6015        let anchor = self.anchor_before(offset);
6016        let excerpt_id = anchor.excerpt_id;
6017        let excerpt = self.excerpt(excerpt_id)?;
6018        Some((
6019            excerpt.buffer_id,
6020            excerpt
6021                .buffer
6022                .symbols_containing(anchor.text_anchor, theme)
6023                .into_iter()
6024                .flatten()
6025                .flat_map(|item| {
6026                    Some(OutlineItem {
6027                        depth: item.depth,
6028                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6029                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6030                        text: item.text,
6031                        highlight_ranges: item.highlight_ranges,
6032                        name_ranges: item.name_ranges,
6033                        body_range: item.body_range.and_then(|body_range| {
6034                            Some(
6035                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6036                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6037                            )
6038                        }),
6039                        annotation_range: item.annotation_range.and_then(|body_range| {
6040                            Some(
6041                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6042                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6043                            )
6044                        }),
6045                    })
6046                })
6047                .collect(),
6048        ))
6049    }
6050
6051    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6052        if id == ExcerptId::min() {
6053            Locator::min_ref()
6054        } else if id == ExcerptId::max() {
6055            Locator::max_ref()
6056        } else {
6057            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6058            cursor.seek(&id, Bias::Left, &());
6059            if let Some(entry) = cursor.item() {
6060                if entry.id == id {
6061                    return &entry.locator;
6062                }
6063            }
6064            panic!("invalid excerpt id {:?}", id)
6065        }
6066    }
6067
6068    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6069    fn excerpt_locators_for_ids(
6070        &self,
6071        ids: impl IntoIterator<Item = ExcerptId>,
6072    ) -> SmallVec<[Locator; 1]> {
6073        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6074        sorted_ids.sort_unstable();
6075        let mut locators = SmallVec::new();
6076
6077        while sorted_ids.last() == Some(&ExcerptId::max()) {
6078            sorted_ids.pop();
6079            if let Some(mapping) = self.excerpt_ids.last() {
6080                locators.push(mapping.locator.clone());
6081            }
6082        }
6083
6084        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6085        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6086            sorted_ids.next();
6087            if let Some(mapping) = self.excerpt_ids.first() {
6088                locators.push(mapping.locator.clone());
6089            }
6090        }
6091
6092        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6093        for id in sorted_ids {
6094            if cursor.seek_forward(&id, Bias::Left, &()) {
6095                locators.push(cursor.item().unwrap().locator.clone());
6096            } else {
6097                panic!("invalid excerpt id {:?}", id);
6098            }
6099        }
6100
6101        locators.sort_unstable();
6102        locators
6103    }
6104
6105    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6106        Some(self.excerpt(excerpt_id)?.buffer_id)
6107    }
6108
6109    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6110        Some(&self.excerpt(excerpt_id)?.buffer)
6111    }
6112
6113    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6114        let mut cursor = self
6115            .excerpts
6116            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6117        let locator = self.excerpt_locator_for_id(excerpt_id);
6118        if cursor.seek(&Some(locator), Bias::Left, &()) {
6119            let start = cursor.start().1.clone();
6120            let end = cursor.end(&()).1;
6121            let mut diff_transforms = self
6122                .diff_transforms
6123                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6124            diff_transforms.seek(&start, Bias::Left, &());
6125            let overshoot = start.0 - diff_transforms.start().0.0;
6126            let start = diff_transforms.start().1.0 + overshoot;
6127            diff_transforms.seek(&end, Bias::Right, &());
6128            let overshoot = end.0 - diff_transforms.start().0.0;
6129            let end = diff_transforms.start().1.0 + overshoot;
6130            Some(start..end)
6131        } else {
6132            None
6133        }
6134    }
6135
6136    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6137        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6138        let locator = self.excerpt_locator_for_id(excerpt_id);
6139        if cursor.seek(&Some(locator), Bias::Left, &()) {
6140            if let Some(excerpt) = cursor.item() {
6141                return Some(excerpt.range.context.clone());
6142            }
6143        }
6144        None
6145    }
6146
6147    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6148        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6149        let locator = self.excerpt_locator_for_id(excerpt_id);
6150        cursor.seek(&Some(locator), Bias::Left, &());
6151        if let Some(excerpt) = cursor.item() {
6152            if excerpt.id == excerpt_id {
6153                return Some(excerpt);
6154            }
6155        }
6156        None
6157    }
6158
6159    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6160    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
6161        let range = range.start.to_offset(self)..range.end.to_offset(self);
6162        let mut cursor = self.cursor::<usize>();
6163        cursor.seek(&range.start);
6164
6165        let start_excerpt = cursor.excerpt()?;
6166        if range.end != range.start {
6167            cursor.seek_forward(&range.end);
6168            if cursor.excerpt()?.id != start_excerpt.id {
6169                return None;
6170            }
6171        }
6172
6173        cursor.seek_to_start_of_current_excerpt();
6174        let region = cursor.region()?;
6175        let offset = region.range.start;
6176        let buffer_offset = region.buffer_range.start;
6177        let excerpt_offset = cursor.excerpts.start().clone();
6178        Some(MultiBufferExcerpt {
6179            diff_transforms: cursor.diff_transforms,
6180            excerpt: start_excerpt,
6181            offset,
6182            buffer_offset,
6183            excerpt_offset,
6184        })
6185    }
6186
6187    pub fn selections_in_range<'a>(
6188        &'a self,
6189        range: &'a Range<Anchor>,
6190        include_local: bool,
6191    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6192        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6193        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6194        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6195        cursor.seek(start_locator, Bias::Left, &());
6196        cursor
6197            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6198            .flat_map(move |excerpt| {
6199                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6200                if excerpt.id == range.start.excerpt_id {
6201                    query_range.start = range.start.text_anchor;
6202                }
6203                if excerpt.id == range.end.excerpt_id {
6204                    query_range.end = range.end.text_anchor;
6205                }
6206
6207                excerpt
6208                    .buffer
6209                    .selections_in_range(query_range, include_local)
6210                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6211                        selections.map(move |selection| {
6212                            let mut start = Anchor {
6213                                buffer_id: Some(excerpt.buffer_id),
6214                                excerpt_id: excerpt.id,
6215                                text_anchor: selection.start,
6216                                diff_base_anchor: None,
6217                            };
6218                            let mut end = Anchor {
6219                                buffer_id: Some(excerpt.buffer_id),
6220                                excerpt_id: excerpt.id,
6221                                text_anchor: selection.end,
6222                                diff_base_anchor: None,
6223                            };
6224                            if range.start.cmp(&start, self).is_gt() {
6225                                start = range.start;
6226                            }
6227                            if range.end.cmp(&end, self).is_lt() {
6228                                end = range.end;
6229                            }
6230
6231                            (
6232                                replica_id,
6233                                line_mode,
6234                                cursor_shape,
6235                                Selection {
6236                                    id: selection.id,
6237                                    start,
6238                                    end,
6239                                    reversed: selection.reversed,
6240                                    goal: selection.goal,
6241                                },
6242                            )
6243                        })
6244                    })
6245            })
6246    }
6247
6248    pub fn show_headers(&self) -> bool {
6249        self.show_headers
6250    }
6251
6252    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6253        self.diffs.get(&buffer_id)
6254    }
6255}
6256
6257#[cfg(any(test, feature = "test-support"))]
6258impl MultiBufferSnapshot {
6259    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6260        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6261        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6262        start..end
6263    }
6264
6265    #[cfg(any(test, feature = "test-support"))]
6266    fn check_invariants(&self) {
6267        let excerpts = self.excerpts.items(&());
6268        let excerpt_ids = self.excerpt_ids.items(&());
6269
6270        for (ix, excerpt) in excerpts.iter().enumerate() {
6271            if ix == 0 {
6272                if excerpt.locator <= Locator::min() {
6273                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6274                }
6275            } else if excerpt.locator <= excerpts[ix - 1].locator {
6276                panic!("excerpts are out-of-order: {:?}", excerpts);
6277            }
6278        }
6279
6280        for (ix, entry) in excerpt_ids.iter().enumerate() {
6281            if ix == 0 {
6282                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6283                    panic!("invalid first excerpt id {:?}", entry.id);
6284                }
6285            } else if entry.id <= excerpt_ids[ix - 1].id {
6286                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6287            }
6288        }
6289
6290        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6291            panic!(
6292                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6293                self.excerpts.summary().text.len,
6294                self.diff_transforms.summary().input,
6295                self.diff_transforms.items(&()),
6296            );
6297        }
6298
6299        let mut prev_transform: Option<&DiffTransform> = None;
6300        for item in self.diff_transforms.iter() {
6301            if let DiffTransform::BufferContent {
6302                summary,
6303                inserted_hunk_info,
6304            } = item
6305            {
6306                if let Some(DiffTransform::BufferContent {
6307                    inserted_hunk_info: prev_inserted_hunk_info,
6308                    ..
6309                }) = prev_transform
6310                {
6311                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6312                        panic!(
6313                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6314                            self.diff_transforms.items(&())
6315                        );
6316                    }
6317                }
6318                if summary.len == 0 && !self.is_empty() {
6319                    panic!("empty buffer content transform");
6320                }
6321            }
6322            prev_transform = Some(item);
6323        }
6324    }
6325}
6326
6327impl<'a, D> MultiBufferCursor<'a, D>
6328where
6329    D: TextDimension + Ord + Sub<D, Output = D>,
6330{
6331    fn seek(&mut self, position: &D) {
6332        self.cached_region.take();
6333        self.diff_transforms
6334            .seek(&OutputDimension(*position), Bias::Right, &());
6335        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6336            self.diff_transforms.prev(&());
6337        }
6338
6339        let mut excerpt_position = self.diff_transforms.start().1.0;
6340        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6341            let overshoot = *position - self.diff_transforms.start().0.0;
6342            excerpt_position.add_assign(&overshoot);
6343        }
6344
6345        self.excerpts
6346            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6347        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6348            self.excerpts.prev(&());
6349        }
6350    }
6351
6352    fn seek_forward(&mut self, position: &D) {
6353        self.cached_region.take();
6354        self.diff_transforms
6355            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6356        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6357            self.diff_transforms.prev(&());
6358        }
6359
6360        let overshoot = *position - self.diff_transforms.start().0.0;
6361        let mut excerpt_position = self.diff_transforms.start().1.0;
6362        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6363            excerpt_position.add_assign(&overshoot);
6364        }
6365
6366        self.excerpts
6367            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6368        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6369            self.excerpts.prev(&());
6370        }
6371    }
6372
6373    fn next_excerpt(&mut self) {
6374        self.excerpts.next(&());
6375        self.seek_to_start_of_current_excerpt();
6376    }
6377
6378    fn prev_excerpt(&mut self) {
6379        self.excerpts.prev(&());
6380        self.seek_to_start_of_current_excerpt();
6381    }
6382
6383    fn seek_to_start_of_current_excerpt(&mut self) {
6384        self.cached_region.take();
6385        self.diff_transforms
6386            .seek(self.excerpts.start(), Bias::Left, &());
6387        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6388            && self.diff_transforms.start().1 < *self.excerpts.start()
6389            && self.diff_transforms.next_item().is_some()
6390        {
6391            self.diff_transforms.next(&());
6392        }
6393    }
6394
6395    fn next(&mut self) {
6396        self.cached_region.take();
6397        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6398            cmp::Ordering::Less => self.diff_transforms.next(&()),
6399            cmp::Ordering::Greater => self.excerpts.next(&()),
6400            cmp::Ordering::Equal => {
6401                self.diff_transforms.next(&());
6402                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6403                    || self.diff_transforms.item().is_none()
6404                {
6405                    self.excerpts.next(&());
6406                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6407                    self.diff_transforms.item()
6408                {
6409                    if self
6410                        .excerpts
6411                        .item()
6412                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6413                    {
6414                        self.excerpts.next(&());
6415                    }
6416                }
6417            }
6418        }
6419    }
6420
6421    fn prev(&mut self) {
6422        self.cached_region.take();
6423        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6424            cmp::Ordering::Less => self.excerpts.prev(&()),
6425            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6426            cmp::Ordering::Equal => {
6427                self.diff_transforms.prev(&());
6428                if self.diff_transforms.start().1 < *self.excerpts.start()
6429                    || self.diff_transforms.item().is_none()
6430                {
6431                    self.excerpts.prev(&());
6432                }
6433            }
6434        }
6435    }
6436
6437    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6438        if self.cached_region.is_none() {
6439            self.cached_region = self.build_region();
6440        }
6441        self.cached_region.clone()
6442    }
6443
6444    fn is_at_start_of_excerpt(&mut self) -> bool {
6445        if self.diff_transforms.start().1 > *self.excerpts.start() {
6446            return false;
6447        } else if self.diff_transforms.start().1 < *self.excerpts.start() {
6448            return true;
6449        }
6450
6451        self.diff_transforms.prev(&());
6452        let prev_transform = self.diff_transforms.item();
6453        self.diff_transforms.next(&());
6454
6455        prev_transform.map_or(true, |next_transform| {
6456            matches!(next_transform, DiffTransform::BufferContent { .. })
6457        })
6458    }
6459
6460    fn is_at_end_of_excerpt(&mut self) -> bool {
6461        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6462            return false;
6463        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6464            || self.diff_transforms.item().is_none()
6465        {
6466            return true;
6467        }
6468
6469        let next_transform = self.diff_transforms.next_item();
6470        next_transform.map_or(true, |next_transform| match next_transform {
6471            DiffTransform::BufferContent { .. } => true,
6472            DiffTransform::DeletedHunk { hunk_info, .. } => self
6473                .excerpts
6474                .item()
6475                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6476        })
6477    }
6478
6479    fn main_buffer_position(&self) -> Option<D> {
6480        let excerpt = self.excerpts.item()?;
6481        let buffer = &excerpt.buffer;
6482        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6483        let mut buffer_start = buffer_context_start;
6484        let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6485        buffer_start.add_assign(&overshoot);
6486        Some(buffer_start)
6487    }
6488
6489    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6490        let excerpt = self.excerpts.item()?;
6491        match self.diff_transforms.item()? {
6492            DiffTransform::DeletedHunk {
6493                buffer_id,
6494                base_text_byte_range,
6495                has_trailing_newline,
6496                hunk_info,
6497                ..
6498            } => {
6499                let diff = self.diffs.get(&buffer_id)?;
6500                let buffer = diff.base_text();
6501                let mut rope_cursor = buffer.as_rope().cursor(0);
6502                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6503                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6504                let mut buffer_end = buffer_start;
6505                buffer_end.add_assign(&buffer_range_len);
6506                let start = self.diff_transforms.start().0.0;
6507                let end = self.diff_transforms.end(&()).0.0;
6508                return Some(MultiBufferRegion {
6509                    buffer,
6510                    excerpt,
6511                    has_trailing_newline: *has_trailing_newline,
6512                    is_main_buffer: false,
6513                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6514                        hunk_info.hunk_secondary_status,
6515                    )),
6516                    buffer_range: buffer_start..buffer_end,
6517                    range: start..end,
6518                });
6519            }
6520            DiffTransform::BufferContent {
6521                inserted_hunk_info, ..
6522            } => {
6523                let buffer = &excerpt.buffer;
6524                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6525
6526                let mut start = self.diff_transforms.start().0.0;
6527                let mut buffer_start = buffer_context_start;
6528                if self.diff_transforms.start().1 < *self.excerpts.start() {
6529                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1.0;
6530                    start.add_assign(&overshoot);
6531                } else {
6532                    let overshoot = self.diff_transforms.start().1.0 - self.excerpts.start().0;
6533                    buffer_start.add_assign(&overshoot);
6534                }
6535
6536                let mut end;
6537                let mut buffer_end;
6538                let has_trailing_newline;
6539                if self.diff_transforms.end(&()).1.0 < self.excerpts.end(&()).0 {
6540                    let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6541                    end = self.diff_transforms.end(&()).0.0;
6542                    buffer_end = buffer_context_start;
6543                    buffer_end.add_assign(&overshoot);
6544                    has_trailing_newline = false;
6545                } else {
6546                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1.0;
6547                    end = self.diff_transforms.start().0.0;
6548                    end.add_assign(&overshoot);
6549                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6550                    has_trailing_newline = excerpt.has_trailing_newline;
6551                };
6552
6553                Some(MultiBufferRegion {
6554                    buffer,
6555                    excerpt,
6556                    has_trailing_newline,
6557                    is_main_buffer: true,
6558                    diff_hunk_status: inserted_hunk_info
6559                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6560                    buffer_range: buffer_start..buffer_end,
6561                    range: start..end,
6562                })
6563            }
6564        }
6565    }
6566
6567    fn excerpt(&self) -> Option<&'a Excerpt> {
6568        self.excerpts.item()
6569    }
6570}
6571
6572impl History {
6573    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6574        self.transaction_depth += 1;
6575        if self.transaction_depth == 1 {
6576            let id = self.next_transaction_id.tick();
6577            self.undo_stack.push(Transaction {
6578                id,
6579                buffer_transactions: Default::default(),
6580                first_edit_at: now,
6581                last_edit_at: now,
6582                suppress_grouping: false,
6583            });
6584            Some(id)
6585        } else {
6586            None
6587        }
6588    }
6589
6590    fn end_transaction(
6591        &mut self,
6592        now: Instant,
6593        buffer_transactions: HashMap<BufferId, TransactionId>,
6594    ) -> bool {
6595        assert_ne!(self.transaction_depth, 0);
6596        self.transaction_depth -= 1;
6597        if self.transaction_depth == 0 {
6598            if buffer_transactions.is_empty() {
6599                self.undo_stack.pop();
6600                false
6601            } else {
6602                self.redo_stack.clear();
6603                let transaction = self.undo_stack.last_mut().unwrap();
6604                transaction.last_edit_at = now;
6605                for (buffer_id, transaction_id) in buffer_transactions {
6606                    transaction
6607                        .buffer_transactions
6608                        .entry(buffer_id)
6609                        .or_insert(transaction_id);
6610                }
6611                true
6612            }
6613        } else {
6614            false
6615        }
6616    }
6617
6618    fn push_transaction<'a, T>(
6619        &mut self,
6620        buffer_transactions: T,
6621        now: Instant,
6622        cx: &Context<MultiBuffer>,
6623    ) where
6624        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6625    {
6626        assert_eq!(self.transaction_depth, 0);
6627        let transaction = Transaction {
6628            id: self.next_transaction_id.tick(),
6629            buffer_transactions: buffer_transactions
6630                .into_iter()
6631                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6632                .collect(),
6633            first_edit_at: now,
6634            last_edit_at: now,
6635            suppress_grouping: false,
6636        };
6637        if !transaction.buffer_transactions.is_empty() {
6638            self.undo_stack.push(transaction);
6639            self.redo_stack.clear();
6640        }
6641    }
6642
6643    fn finalize_last_transaction(&mut self) {
6644        if let Some(transaction) = self.undo_stack.last_mut() {
6645            transaction.suppress_grouping = true;
6646        }
6647    }
6648
6649    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6650        if let Some(ix) = self
6651            .undo_stack
6652            .iter()
6653            .rposition(|transaction| transaction.id == transaction_id)
6654        {
6655            Some(self.undo_stack.remove(ix))
6656        } else if let Some(ix) = self
6657            .redo_stack
6658            .iter()
6659            .rposition(|transaction| transaction.id == transaction_id)
6660        {
6661            Some(self.redo_stack.remove(ix))
6662        } else {
6663            None
6664        }
6665    }
6666
6667    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6668        self.undo_stack
6669            .iter()
6670            .find(|transaction| transaction.id == transaction_id)
6671            .or_else(|| {
6672                self.redo_stack
6673                    .iter()
6674                    .find(|transaction| transaction.id == transaction_id)
6675            })
6676    }
6677
6678    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6679        self.undo_stack
6680            .iter_mut()
6681            .find(|transaction| transaction.id == transaction_id)
6682            .or_else(|| {
6683                self.redo_stack
6684                    .iter_mut()
6685                    .find(|transaction| transaction.id == transaction_id)
6686            })
6687    }
6688
6689    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6690        assert_eq!(self.transaction_depth, 0);
6691        if let Some(transaction) = self.undo_stack.pop() {
6692            self.redo_stack.push(transaction);
6693            self.redo_stack.last_mut()
6694        } else {
6695            None
6696        }
6697    }
6698
6699    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6700        assert_eq!(self.transaction_depth, 0);
6701        if let Some(transaction) = self.redo_stack.pop() {
6702            self.undo_stack.push(transaction);
6703            self.undo_stack.last_mut()
6704        } else {
6705            None
6706        }
6707    }
6708
6709    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6710        let ix = self
6711            .undo_stack
6712            .iter()
6713            .rposition(|transaction| transaction.id == transaction_id)?;
6714        let transaction = self.undo_stack.remove(ix);
6715        self.redo_stack.push(transaction);
6716        self.redo_stack.last()
6717    }
6718
6719    fn group(&mut self) -> Option<TransactionId> {
6720        let mut count = 0;
6721        let mut transactions = self.undo_stack.iter();
6722        if let Some(mut transaction) = transactions.next_back() {
6723            while let Some(prev_transaction) = transactions.next_back() {
6724                if !prev_transaction.suppress_grouping
6725                    && transaction.first_edit_at - prev_transaction.last_edit_at
6726                        <= self.group_interval
6727                {
6728                    transaction = prev_transaction;
6729                    count += 1;
6730                } else {
6731                    break;
6732                }
6733            }
6734        }
6735        self.group_trailing(count)
6736    }
6737
6738    fn group_until(&mut self, transaction_id: TransactionId) {
6739        let mut count = 0;
6740        for transaction in self.undo_stack.iter().rev() {
6741            if transaction.id == transaction_id {
6742                self.group_trailing(count);
6743                break;
6744            } else if transaction.suppress_grouping {
6745                break;
6746            } else {
6747                count += 1;
6748            }
6749        }
6750    }
6751
6752    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6753        let new_len = self.undo_stack.len() - n;
6754        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6755        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6756            if let Some(transaction) = transactions_to_merge.last() {
6757                last_transaction.last_edit_at = transaction.last_edit_at;
6758            }
6759            for to_merge in transactions_to_merge {
6760                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6761                    last_transaction
6762                        .buffer_transactions
6763                        .entry(*buffer_id)
6764                        .or_insert(*transaction_id);
6765                }
6766            }
6767        }
6768
6769        self.undo_stack.truncate(new_len);
6770        self.undo_stack.last().map(|t| t.id)
6771    }
6772}
6773
6774impl Excerpt {
6775    fn new(
6776        id: ExcerptId,
6777        locator: Locator,
6778        buffer_id: BufferId,
6779        buffer: BufferSnapshot,
6780        range: ExcerptRange<text::Anchor>,
6781        has_trailing_newline: bool,
6782    ) -> Self {
6783        Excerpt {
6784            id,
6785            locator,
6786            max_buffer_row: range.context.end.to_point(&buffer).row,
6787            text_summary: buffer
6788                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6789            buffer_id,
6790            buffer,
6791            range,
6792            has_trailing_newline,
6793        }
6794    }
6795
6796    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6797        let content_start = self.range.context.start.to_offset(&self.buffer);
6798        let chunks_start = content_start + range.start;
6799        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6800
6801        let footer_height = if self.has_trailing_newline
6802            && range.start <= self.text_summary.len
6803            && range.end > self.text_summary.len
6804        {
6805            1
6806        } else {
6807            0
6808        };
6809
6810        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6811
6812        ExcerptChunks {
6813            excerpt_id: self.id,
6814            content_chunks,
6815            footer_height,
6816        }
6817    }
6818
6819    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6820        let content_start = self.range.context.start.to_offset(&self.buffer);
6821        let chunks_start = content_start + range.start;
6822        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6823        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6824        excerpt_chunks.footer_height = if self.has_trailing_newline
6825            && range.start <= self.text_summary.len
6826            && range.end > self.text_summary.len
6827        {
6828            1
6829        } else {
6830            0
6831        };
6832    }
6833
6834    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6835        if text_anchor
6836            .cmp(&self.range.context.start, &self.buffer)
6837            .is_lt()
6838        {
6839            self.range.context.start
6840        } else if text_anchor
6841            .cmp(&self.range.context.end, &self.buffer)
6842            .is_gt()
6843        {
6844            self.range.context.end
6845        } else {
6846            text_anchor
6847        }
6848    }
6849
6850    fn contains(&self, anchor: &Anchor) -> bool {
6851        Some(self.buffer_id) == anchor.buffer_id
6852            && self
6853                .range
6854                .context
6855                .start
6856                .cmp(&anchor.text_anchor, &self.buffer)
6857                .is_le()
6858            && self
6859                .range
6860                .context
6861                .end
6862                .cmp(&anchor.text_anchor, &self.buffer)
6863                .is_ge()
6864    }
6865
6866    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6867    fn buffer_start_offset(&self) -> usize {
6868        self.range.context.start.to_offset(&self.buffer)
6869    }
6870
6871    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6872    fn buffer_end_offset(&self) -> usize {
6873        self.buffer_start_offset() + self.text_summary.len
6874    }
6875}
6876
6877impl<'a> MultiBufferExcerpt<'a> {
6878    pub fn id(&self) -> ExcerptId {
6879        self.excerpt.id
6880    }
6881
6882    pub fn buffer_id(&self) -> BufferId {
6883        self.excerpt.buffer_id
6884    }
6885
6886    pub fn start_anchor(&self) -> Anchor {
6887        Anchor {
6888            buffer_id: Some(self.excerpt.buffer_id),
6889            excerpt_id: self.excerpt.id,
6890            text_anchor: self.excerpt.range.context.start,
6891            diff_base_anchor: None,
6892        }
6893    }
6894
6895    pub fn end_anchor(&self) -> Anchor {
6896        Anchor {
6897            buffer_id: Some(self.excerpt.buffer_id),
6898            excerpt_id: self.excerpt.id,
6899            text_anchor: self.excerpt.range.context.end,
6900            diff_base_anchor: None,
6901        }
6902    }
6903
6904    pub fn buffer(&self) -> &'a BufferSnapshot {
6905        &self.excerpt.buffer
6906    }
6907
6908    pub fn buffer_range(&self) -> Range<usize> {
6909        self.buffer_offset
6910            ..self
6911                .excerpt
6912                .range
6913                .context
6914                .end
6915                .to_offset(&self.excerpt.buffer.text)
6916    }
6917
6918    pub fn start_offset(&self) -> usize {
6919        self.offset
6920    }
6921
6922    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6923    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6924        self.map_range_to_buffer(offset..offset).start
6925    }
6926
6927    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6928    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6929        self.diff_transforms
6930            .seek(&OutputDimension(range.start), Bias::Right, &());
6931        let start = self.map_offset_to_buffer_internal(range.start);
6932        let end = if range.end > range.start {
6933            self.diff_transforms
6934                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6935            self.map_offset_to_buffer_internal(range.end)
6936        } else {
6937            start
6938        };
6939        start..end
6940    }
6941
6942    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6943        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6944        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6945            excerpt_offset.0 += offset - self.diff_transforms.start().0.0;
6946        };
6947        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6948        self.buffer_offset + offset_in_excerpt
6949    }
6950
6951    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6952    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6953        self.map_range_from_buffer(buffer_offset..buffer_offset)
6954            .start
6955    }
6956
6957    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6958    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6959        if buffer_range.start < self.buffer_offset {
6960            log::warn!(
6961                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6962            );
6963            return buffer_range;
6964        }
6965        let overshoot = buffer_range.start - self.buffer_offset;
6966        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6967        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6968        if excerpt_offset.0 < self.diff_transforms.start().1.0 {
6969            log::warn!(
6970                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6971            );
6972            return buffer_range;
6973        }
6974        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
6975        let start = self.diff_transforms.start().0.0 + overshoot;
6976
6977        let end = if buffer_range.end > buffer_range.start {
6978            let overshoot = buffer_range.end - self.buffer_offset;
6979            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6980            self.diff_transforms
6981                .seek_forward(&excerpt_offset, Bias::Right, &());
6982            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
6983            self.diff_transforms.start().0.0 + overshoot
6984        } else {
6985            start
6986        };
6987
6988        start..end
6989    }
6990
6991    /// Returns true if the entirety of the given range is in the buffer's excerpt
6992    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6993        range.start >= self.excerpt.buffer_start_offset()
6994            && range.end <= self.excerpt.buffer_end_offset()
6995    }
6996
6997    pub fn max_buffer_row(&self) -> u32 {
6998        self.excerpt.max_buffer_row
6999    }
7000}
7001
7002impl ExcerptId {
7003    pub fn min() -> Self {
7004        Self(0)
7005    }
7006
7007    pub fn max() -> Self {
7008        Self(usize::MAX)
7009    }
7010
7011    pub fn to_proto(&self) -> u64 {
7012        self.0 as _
7013    }
7014
7015    pub fn from_proto(proto: u64) -> Self {
7016        Self(proto as _)
7017    }
7018
7019    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7020        let a = snapshot.excerpt_locator_for_id(*self);
7021        let b = snapshot.excerpt_locator_for_id(*other);
7022        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7023    }
7024}
7025
7026impl From<ExcerptId> for usize {
7027    fn from(val: ExcerptId) -> Self {
7028        val.0
7029    }
7030}
7031
7032impl fmt::Debug for Excerpt {
7033    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7034        f.debug_struct("Excerpt")
7035            .field("id", &self.id)
7036            .field("locator", &self.locator)
7037            .field("buffer_id", &self.buffer_id)
7038            .field("range", &self.range)
7039            .field("text_summary", &self.text_summary)
7040            .field("has_trailing_newline", &self.has_trailing_newline)
7041            .finish()
7042    }
7043}
7044
7045impl sum_tree::Item for Excerpt {
7046    type Summary = ExcerptSummary;
7047
7048    fn summary(&self, _cx: &()) -> Self::Summary {
7049        let mut text = self.text_summary;
7050        if self.has_trailing_newline {
7051            text += TextSummary::from("\n");
7052        }
7053        ExcerptSummary {
7054            excerpt_id: self.id,
7055            excerpt_locator: self.locator.clone(),
7056            widest_line_number: self.max_buffer_row,
7057            text,
7058        }
7059    }
7060}
7061
7062impl sum_tree::Item for ExcerptIdMapping {
7063    type Summary = ExcerptId;
7064
7065    fn summary(&self, _cx: &()) -> Self::Summary {
7066        self.id
7067    }
7068}
7069
7070impl sum_tree::KeyedItem for ExcerptIdMapping {
7071    type Key = ExcerptId;
7072
7073    fn key(&self) -> Self::Key {
7074        self.id
7075    }
7076}
7077
7078impl DiffTransform {
7079    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7080        match self {
7081            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7082            DiffTransform::BufferContent {
7083                inserted_hunk_info, ..
7084            } => *inserted_hunk_info,
7085        }
7086    }
7087}
7088
7089impl sum_tree::Item for DiffTransform {
7090    type Summary = DiffTransformSummary;
7091
7092    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7093        match self {
7094            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7095                input: *summary,
7096                output: *summary,
7097            },
7098            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7099                input: TextSummary::default(),
7100                output: *summary,
7101            },
7102        }
7103    }
7104}
7105
7106impl DiffTransformSummary {
7107    fn excerpt_len(&self) -> ExcerptOffset {
7108        ExcerptOffset::new(self.input.len)
7109    }
7110}
7111
7112impl sum_tree::Summary for DiffTransformSummary {
7113    type Context = ();
7114
7115    fn zero(_: &Self::Context) -> Self {
7116        DiffTransformSummary {
7117            input: TextSummary::default(),
7118            output: TextSummary::default(),
7119        }
7120    }
7121
7122    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7123        self.input += &summary.input;
7124        self.output += &summary.output;
7125    }
7126}
7127
7128impl sum_tree::Summary for ExcerptId {
7129    type Context = ();
7130
7131    fn zero(_cx: &()) -> Self {
7132        Default::default()
7133    }
7134
7135    fn add_summary(&mut self, other: &Self, _: &()) {
7136        *self = *other;
7137    }
7138}
7139
7140impl sum_tree::Summary for ExcerptSummary {
7141    type Context = ();
7142
7143    fn zero(_cx: &()) -> Self {
7144        Default::default()
7145    }
7146
7147    fn add_summary(&mut self, summary: &Self, _: &()) {
7148        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7149        self.excerpt_locator = summary.excerpt_locator.clone();
7150        self.text.add_summary(&summary.text, &());
7151        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7152    }
7153}
7154
7155impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7156    fn zero(_cx: &()) -> Self {
7157        Default::default()
7158    }
7159
7160    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7161        self.value += summary.text.len;
7162    }
7163}
7164
7165impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7166    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7167        Ord::cmp(&self.value, &cursor_location.text.len)
7168    }
7169}
7170
7171impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7172    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7173        Ord::cmp(&Some(self), cursor_location)
7174    }
7175}
7176
7177impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7178    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7179        Ord::cmp(self, &cursor_location.excerpt_locator)
7180    }
7181}
7182
7183impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7184    fn zero(_cx: &()) -> Self {
7185        Default::default()
7186    }
7187
7188    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7189        self.value += summary.text.lines;
7190    }
7191}
7192
7193impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7194    for ExcerptDimension<D>
7195{
7196    fn zero(_: &()) -> Self {
7197        ExcerptDimension(D::default())
7198    }
7199
7200    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7201        self.0.add_assign(&D::from_text_summary(&summary.text))
7202    }
7203}
7204
7205impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7206    fn zero(_cx: &()) -> Self {
7207        Default::default()
7208    }
7209
7210    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7211        *self = Some(&summary.excerpt_locator);
7212    }
7213}
7214
7215impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7216    fn zero(_cx: &()) -> Self {
7217        Default::default()
7218    }
7219
7220    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7221        *self = Some(summary.excerpt_id);
7222    }
7223}
7224
7225#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7226struct ExcerptDimension<T>(T);
7227
7228#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7229struct OutputDimension<T>(T);
7230
7231impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7232    fn zero(_: &()) -> Self {
7233        ExcerptOffset::new(0)
7234    }
7235
7236    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7237        self.value += summary.input.len;
7238    }
7239}
7240
7241impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7242    fn zero(_: &()) -> Self {
7243        ExcerptPoint::new(0, 0)
7244    }
7245
7246    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7247        self.value += summary.input.lines;
7248    }
7249}
7250
7251impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7252    for ExcerptDimension<D>
7253{
7254    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7255        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7256    }
7257}
7258
7259impl<D: TextDimension + Ord>
7260    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7261    for ExcerptDimension<D>
7262{
7263    fn cmp(
7264        &self,
7265        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7266        _: &(),
7267    ) -> cmp::Ordering {
7268        Ord::cmp(&self.0, &cursor_location.1.0)
7269    }
7270}
7271
7272impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7273    fn zero(_: &()) -> Self {
7274        ExcerptDimension(D::default())
7275    }
7276
7277    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7278        self.0.add_assign(&D::from_text_summary(&summary.input))
7279    }
7280}
7281
7282impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7283    fn zero(_: &()) -> Self {
7284        OutputDimension(D::default())
7285    }
7286
7287    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7288        self.0.add_assign(&D::from_text_summary(&summary.output))
7289    }
7290}
7291
7292impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7293    fn zero(_: &()) -> Self {
7294        TextSummary::default()
7295    }
7296
7297    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7298        *self += summary.output
7299    }
7300}
7301
7302impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7303    fn zero(_: &()) -> Self {
7304        0
7305    }
7306
7307    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7308        *self += summary.output.len
7309    }
7310}
7311
7312impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7313    fn zero(_: &()) -> Self {
7314        Point::new(0, 0)
7315    }
7316
7317    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7318        *self += summary.output.lines
7319    }
7320}
7321
7322impl MultiBufferRows<'_> {
7323    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7324        self.point = Point::new(row, 0);
7325        self.cursor.seek(&self.point);
7326    }
7327}
7328
7329impl Iterator for MultiBufferRows<'_> {
7330    type Item = RowInfo;
7331
7332    fn next(&mut self) -> Option<Self::Item> {
7333        if self.is_empty && self.point.row == 0 {
7334            self.point += Point::new(1, 0);
7335            return Some(RowInfo {
7336                buffer_id: None,
7337                buffer_row: Some(0),
7338                multibuffer_row: Some(MultiBufferRow(0)),
7339                diff_status: None,
7340                expand_info: None,
7341            });
7342        }
7343
7344        let mut region = self.cursor.region()?;
7345        while self.point >= region.range.end {
7346            self.cursor.next();
7347            if let Some(next_region) = self.cursor.region() {
7348                region = next_region;
7349            } else {
7350                if self.point == self.cursor.diff_transforms.end(&()).0.0 {
7351                    let multibuffer_row = MultiBufferRow(self.point.row);
7352                    let last_excerpt = self
7353                        .cursor
7354                        .excerpts
7355                        .item()
7356                        .or(self.cursor.excerpts.prev_item())?;
7357                    let last_row = last_excerpt
7358                        .range
7359                        .context
7360                        .end
7361                        .to_point(&last_excerpt.buffer)
7362                        .row;
7363
7364                    let first_row = last_excerpt
7365                        .range
7366                        .context
7367                        .start
7368                        .to_point(&last_excerpt.buffer)
7369                        .row;
7370
7371                    let expand_info = if self.is_singleton {
7372                        None
7373                    } else {
7374                        let needs_expand_up = first_row == last_row
7375                            && last_row > 0
7376                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7377                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7378
7379                        if needs_expand_up && needs_expand_down {
7380                            Some(ExpandExcerptDirection::UpAndDown)
7381                        } else if needs_expand_up {
7382                            Some(ExpandExcerptDirection::Up)
7383                        } else if needs_expand_down {
7384                            Some(ExpandExcerptDirection::Down)
7385                        } else {
7386                            None
7387                        }
7388                        .map(|direction| ExpandInfo {
7389                            direction,
7390                            excerpt_id: last_excerpt.id,
7391                        })
7392                    };
7393                    self.point += Point::new(1, 0);
7394                    return Some(RowInfo {
7395                        buffer_id: Some(last_excerpt.buffer_id),
7396                        buffer_row: Some(last_row),
7397                        multibuffer_row: Some(multibuffer_row),
7398                        diff_status: None,
7399                        expand_info,
7400                    });
7401                } else {
7402                    return None;
7403                }
7404            };
7405        }
7406
7407        let overshoot = self.point - region.range.start;
7408        let buffer_point = region.buffer_range.start + overshoot;
7409        let expand_info = if self.is_singleton {
7410            None
7411        } else {
7412            let needs_expand_up = self.point.row == region.range.start.row
7413                && self.cursor.is_at_start_of_excerpt()
7414                && buffer_point.row > 0;
7415            let needs_expand_down = (region.excerpt.has_trailing_newline
7416                && self.point.row + 1 == region.range.end.row
7417                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7418                && self.cursor.is_at_end_of_excerpt()
7419                && buffer_point.row < region.buffer.max_point().row;
7420
7421            if needs_expand_up && needs_expand_down {
7422                Some(ExpandExcerptDirection::UpAndDown)
7423            } else if needs_expand_up {
7424                Some(ExpandExcerptDirection::Up)
7425            } else if needs_expand_down {
7426                Some(ExpandExcerptDirection::Down)
7427            } else {
7428                None
7429            }
7430            .map(|direction| ExpandInfo {
7431                direction,
7432                excerpt_id: region.excerpt.id,
7433            })
7434        };
7435
7436        let result = Some(RowInfo {
7437            buffer_id: Some(region.buffer.remote_id()),
7438            buffer_row: Some(buffer_point.row),
7439            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7440            diff_status: region
7441                .diff_hunk_status
7442                .filter(|_| self.point < region.range.end),
7443            expand_info,
7444        });
7445        self.point += Point::new(1, 0);
7446        result
7447    }
7448}
7449
7450impl<'a> MultiBufferChunks<'a> {
7451    pub fn offset(&self) -> usize {
7452        self.range.start
7453    }
7454
7455    pub fn seek(&mut self, range: Range<usize>) {
7456        self.diff_transforms.seek(&range.end, Bias::Right, &());
7457        let mut excerpt_end = self.diff_transforms.start().1;
7458        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7459            let overshoot = range.end - self.diff_transforms.start().0;
7460            excerpt_end.value += overshoot;
7461        }
7462
7463        self.diff_transforms.seek(&range.start, Bias::Right, &());
7464        let mut excerpt_start = self.diff_transforms.start().1;
7465        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7466            let overshoot = range.start - self.diff_transforms.start().0;
7467            excerpt_start.value += overshoot;
7468        }
7469
7470        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7471        self.buffer_chunk.take();
7472        self.range = range;
7473    }
7474
7475    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7476        self.excerpt_offset_range = new_range.clone();
7477        self.excerpts.seek(&new_range.start, Bias::Right, &());
7478        if let Some(excerpt) = self.excerpts.item() {
7479            let excerpt_start = *self.excerpts.start();
7480            if let Some(excerpt_chunks) = self
7481                .excerpt_chunks
7482                .as_mut()
7483                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7484            {
7485                excerpt.seek_chunks(
7486                    excerpt_chunks,
7487                    (self.excerpt_offset_range.start - excerpt_start).value
7488                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7489                );
7490            } else {
7491                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7492                    (self.excerpt_offset_range.start - excerpt_start).value
7493                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7494                    self.language_aware,
7495                ));
7496            }
7497        } else {
7498            self.excerpt_chunks = None;
7499        }
7500    }
7501
7502    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7503        loop {
7504            if self.excerpt_offset_range.is_empty() {
7505                return None;
7506            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7507                self.excerpt_offset_range.start.value += chunk.text.len();
7508                return Some(chunk);
7509            } else {
7510                self.excerpts.next(&());
7511                let excerpt = self.excerpts.item()?;
7512                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7513                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7514                    self.language_aware,
7515                ));
7516            }
7517        }
7518    }
7519}
7520
7521impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7522    type Item = &'a str;
7523
7524    fn next(&mut self) -> Option<Self::Item> {
7525        let mut region = self.cursor.region()?;
7526        if self.offset == region.range.start {
7527            self.cursor.prev();
7528            region = self.cursor.region()?;
7529            let start_overshoot = self.start.saturating_sub(region.range.start);
7530            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7531                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7532            ));
7533        }
7534
7535        if self.offset == region.range.end && region.has_trailing_newline {
7536            self.offset -= 1;
7537            Some("\n")
7538        } else {
7539            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7540            self.offset -= chunk.len();
7541            Some(chunk)
7542        }
7543    }
7544}
7545
7546impl<'a> Iterator for MultiBufferChunks<'a> {
7547    type Item = Chunk<'a>;
7548
7549    fn next(&mut self) -> Option<Chunk<'a>> {
7550        if self.range.start >= self.range.end {
7551            return None;
7552        }
7553        if self.range.start == self.diff_transforms.end(&()).0 {
7554            self.diff_transforms.next(&());
7555        }
7556
7557        let diff_transform_start = self.diff_transforms.start().0;
7558        let diff_transform_end = self.diff_transforms.end(&()).0;
7559        debug_assert!(self.range.start < diff_transform_end);
7560
7561        let diff_transform = self.diff_transforms.item()?;
7562        match diff_transform {
7563            DiffTransform::BufferContent { .. } => {
7564                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7565                    chunk
7566                } else {
7567                    let chunk = self.next_excerpt_chunk().unwrap();
7568                    self.buffer_chunk.insert(chunk)
7569                };
7570
7571                let chunk_end = self.range.start + chunk.text.len();
7572                let diff_transform_end = diff_transform_end.min(self.range.end);
7573
7574                if diff_transform_end < chunk_end {
7575                    let (before, after) =
7576                        chunk.text.split_at(diff_transform_end - self.range.start);
7577                    self.range.start = diff_transform_end;
7578                    chunk.text = after;
7579                    Some(Chunk {
7580                        text: before,
7581                        ..chunk.clone()
7582                    })
7583                } else {
7584                    self.range.start = chunk_end;
7585                    self.buffer_chunk.take()
7586                }
7587            }
7588            DiffTransform::DeletedHunk {
7589                buffer_id,
7590                base_text_byte_range,
7591                has_trailing_newline,
7592                ..
7593            } => {
7594                let base_text_start =
7595                    base_text_byte_range.start + self.range.start - diff_transform_start;
7596                let base_text_end =
7597                    base_text_byte_range.start + self.range.end - diff_transform_start;
7598                let base_text_end = base_text_end.min(base_text_byte_range.end);
7599
7600                let mut chunks = if let Some((_, mut chunks)) = self
7601                    .diff_base_chunks
7602                    .take()
7603                    .filter(|(id, _)| id == buffer_id)
7604                {
7605                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7606                    {
7607                        chunks.seek(base_text_start..base_text_end);
7608                    }
7609                    chunks
7610                } else {
7611                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7612                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7613                };
7614
7615                let chunk = if let Some(chunk) = chunks.next() {
7616                    self.range.start += chunk.text.len();
7617                    self.diff_base_chunks = Some((*buffer_id, chunks));
7618                    chunk
7619                } else {
7620                    debug_assert!(has_trailing_newline);
7621                    self.range.start += "\n".len();
7622                    Chunk {
7623                        text: "\n",
7624                        ..Default::default()
7625                    }
7626                };
7627                Some(chunk)
7628            }
7629        }
7630    }
7631}
7632
7633impl MultiBufferBytes<'_> {
7634    fn consume(&mut self, len: usize) {
7635        self.range.start += len;
7636        self.chunk = &self.chunk[len..];
7637
7638        if !self.range.is_empty() && self.chunk.is_empty() {
7639            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7640                self.chunk = chunk;
7641            } else if self.has_trailing_newline {
7642                self.has_trailing_newline = false;
7643                self.chunk = b"\n";
7644            } else {
7645                self.cursor.next();
7646                if let Some(region) = self.cursor.region() {
7647                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7648                        region.buffer_range.start
7649                            ..(region.buffer_range.start + self.range.end - region.range.start)
7650                                .min(region.buffer_range.end),
7651                    );
7652                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7653                    self.excerpt_bytes = Some(excerpt_bytes);
7654                    self.has_trailing_newline =
7655                        region.has_trailing_newline && self.range.end >= region.range.end;
7656                    if self.chunk.is_empty() && self.has_trailing_newline {
7657                        self.has_trailing_newline = false;
7658                        self.chunk = b"\n";
7659                    }
7660                }
7661            }
7662        }
7663    }
7664}
7665
7666impl<'a> Iterator for MultiBufferBytes<'a> {
7667    type Item = &'a [u8];
7668
7669    fn next(&mut self) -> Option<Self::Item> {
7670        let chunk = self.chunk;
7671        if chunk.is_empty() {
7672            None
7673        } else {
7674            self.consume(chunk.len());
7675            Some(chunk)
7676        }
7677    }
7678}
7679
7680impl io::Read for MultiBufferBytes<'_> {
7681    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7682        let len = cmp::min(buf.len(), self.chunk.len());
7683        buf[..len].copy_from_slice(&self.chunk[..len]);
7684        if len > 0 {
7685            self.consume(len);
7686        }
7687        Ok(len)
7688    }
7689}
7690
7691impl io::Read for ReversedMultiBufferBytes<'_> {
7692    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7693        let len = cmp::min(buf.len(), self.chunk.len());
7694        buf[..len].copy_from_slice(&self.chunk[..len]);
7695        buf[..len].reverse();
7696        if len > 0 {
7697            self.range.end -= len;
7698            self.chunk = &self.chunk[..self.chunk.len() - len];
7699            if !self.range.is_empty() && self.chunk.is_empty() {
7700                if let Some(chunk) = self.chunks.next() {
7701                    self.chunk = chunk.as_bytes();
7702                }
7703            }
7704        }
7705        Ok(len)
7706    }
7707}
7708
7709impl<'a> Iterator for ExcerptChunks<'a> {
7710    type Item = Chunk<'a>;
7711
7712    fn next(&mut self) -> Option<Self::Item> {
7713        if let Some(chunk) = self.content_chunks.next() {
7714            return Some(chunk);
7715        }
7716
7717        if self.footer_height > 0 {
7718            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7719            self.footer_height = 0;
7720            return Some(Chunk {
7721                text,
7722                ..Default::default()
7723            });
7724        }
7725
7726        None
7727    }
7728}
7729
7730impl ToOffset for Point {
7731    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7732        snapshot.point_to_offset(*self)
7733    }
7734}
7735
7736impl ToOffset for usize {
7737    #[track_caller]
7738    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7739        assert!(*self <= snapshot.len(), "offset is out of range");
7740        *self
7741    }
7742}
7743
7744impl ToOffset for OffsetUtf16 {
7745    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7746        snapshot.offset_utf16_to_offset(*self)
7747    }
7748}
7749
7750impl ToOffset for PointUtf16 {
7751    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7752        snapshot.point_utf16_to_offset(*self)
7753    }
7754}
7755
7756impl ToOffsetUtf16 for OffsetUtf16 {
7757    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7758        *self
7759    }
7760}
7761
7762impl ToOffsetUtf16 for usize {
7763    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7764        snapshot.offset_to_offset_utf16(*self)
7765    }
7766}
7767
7768impl ToPoint for usize {
7769    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7770        snapshot.offset_to_point(*self)
7771    }
7772}
7773
7774impl ToPoint for Point {
7775    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7776        *self
7777    }
7778}
7779
7780impl ToPointUtf16 for usize {
7781    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7782        snapshot.offset_to_point_utf16(*self)
7783    }
7784}
7785
7786impl ToPointUtf16 for Point {
7787    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7788        snapshot.point_to_point_utf16(*self)
7789    }
7790}
7791
7792impl ToPointUtf16 for PointUtf16 {
7793    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7794        *self
7795    }
7796}
7797
7798impl From<ExcerptId> for EntityId {
7799    fn from(id: ExcerptId) -> Self {
7800        EntityId::from(id.0 as u64)
7801    }
7802}
7803
7804pub fn build_excerpt_ranges<T>(
7805    buffer: &BufferSnapshot,
7806    ranges: &[Range<T>],
7807    context_line_count: u32,
7808) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7809where
7810    T: text::ToPoint,
7811{
7812    let max_point = buffer.max_point();
7813    let mut range_counts = Vec::new();
7814    let mut excerpt_ranges = Vec::new();
7815    let mut range_iter = ranges
7816        .iter()
7817        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7818        .peekable();
7819    while let Some(range) = range_iter.next() {
7820        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7821        let row = (range.end.row + context_line_count).min(max_point.row);
7822        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7823
7824        let mut ranges_in_excerpt = 1;
7825
7826        while let Some(next_range) = range_iter.peek() {
7827            if next_range.start.row <= excerpt_end.row + context_line_count {
7828                let row = (next_range.end.row + context_line_count).min(max_point.row);
7829                excerpt_end = Point::new(row, buffer.line_len(row));
7830
7831                ranges_in_excerpt += 1;
7832                range_iter.next();
7833            } else {
7834                break;
7835            }
7836        }
7837
7838        excerpt_ranges.push(ExcerptRange {
7839            context: excerpt_start..excerpt_end,
7840            primary: range,
7841        });
7842        range_counts.push(ranges_in_excerpt);
7843    }
7844
7845    (excerpt_ranges, range_counts)
7846}