multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{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    locator::Locator,
  50    subscription::{Subscription, Topic},
  51    BufferId, Edit, LineIndent, TextSummary,
  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    trailing_excerpt_update_count: usize,
 279    all_diff_hunks_expanded: bool,
 280    non_text_state_update_count: usize,
 281    edit_count: usize,
 282    is_dirty: bool,
 283    has_deleted_file: bool,
 284    has_conflict: bool,
 285    show_headers: bool,
 286}
 287
 288#[derive(Debug, Clone)]
 289enum DiffTransform {
 290    BufferContent {
 291        summary: TextSummary,
 292        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 293    },
 294    DeletedHunk {
 295        summary: TextSummary,
 296        buffer_id: BufferId,
 297        hunk_info: DiffTransformHunkInfo,
 298        base_text_byte_range: Range<usize>,
 299        has_trailing_newline: bool,
 300    },
 301}
 302
 303#[derive(Clone, Copy, Debug)]
 304struct DiffTransformHunkInfo {
 305    excerpt_id: ExcerptId,
 306    hunk_start_anchor: text::Anchor,
 307    hunk_secondary_status: DiffHunkSecondaryStatus,
 308}
 309
 310impl Eq for DiffTransformHunkInfo {}
 311
 312impl PartialEq for DiffTransformHunkInfo {
 313    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 314        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 315    }
 316}
 317
 318impl std::hash::Hash for DiffTransformHunkInfo {
 319    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 320        self.excerpt_id.hash(state);
 321        self.hunk_start_anchor.hash(state);
 322    }
 323}
 324
 325#[derive(Clone)]
 326pub struct ExcerptInfo {
 327    pub id: ExcerptId,
 328    pub buffer: BufferSnapshot,
 329    pub buffer_id: BufferId,
 330    pub range: ExcerptRange<text::Anchor>,
 331    pub end_row: MultiBufferRow,
 332}
 333
 334impl std::fmt::Debug for ExcerptInfo {
 335    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 336        f.debug_struct(type_name::<Self>())
 337            .field("id", &self.id)
 338            .field("buffer_id", &self.buffer_id)
 339            .field("path", &self.buffer.file().map(|f| f.path()))
 340            .field("range", &self.range)
 341            .finish()
 342    }
 343}
 344
 345/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 346#[derive(Debug)]
 347pub struct ExcerptBoundary {
 348    pub prev: Option<ExcerptInfo>,
 349    pub next: ExcerptInfo,
 350    /// The row in the `MultiBuffer` where the boundary is located
 351    pub row: MultiBufferRow,
 352}
 353
 354impl ExcerptBoundary {
 355    pub fn starts_new_buffer(&self) -> bool {
 356        match (self.prev.as_ref(), &self.next) {
 357            (None, _) => true,
 358            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 359        }
 360    }
 361}
 362
 363#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 364pub struct ExpandInfo {
 365    pub direction: ExpandExcerptDirection,
 366    pub excerpt_id: ExcerptId,
 367}
 368
 369#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 370pub struct RowInfo {
 371    pub buffer_id: Option<BufferId>,
 372    pub buffer_row: Option<u32>,
 373    pub multibuffer_row: Option<MultiBufferRow>,
 374    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 375    pub expand_info: Option<ExpandInfo>,
 376}
 377
 378/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 379#[derive(Clone)]
 380struct Excerpt {
 381    /// The unique identifier for this excerpt
 382    id: ExcerptId,
 383    /// The location of the excerpt in the [`MultiBuffer`]
 384    locator: Locator,
 385    /// The buffer being excerpted
 386    buffer_id: BufferId,
 387    /// A snapshot of the buffer being excerpted
 388    buffer: BufferSnapshot,
 389    /// The range of the buffer to be shown in the excerpt
 390    range: ExcerptRange<text::Anchor>,
 391    /// The last row in the excerpted slice of the buffer
 392    max_buffer_row: BufferRow,
 393    /// A summary of the text in the excerpt
 394    text_summary: TextSummary,
 395    has_trailing_newline: bool,
 396}
 397
 398/// A public view into an `Excerpt` in a [`MultiBuffer`].
 399///
 400/// Contains methods for getting the [`Buffer`] of the excerpt,
 401/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 402#[derive(Clone)]
 403pub struct MultiBufferExcerpt<'a> {
 404    excerpt: &'a Excerpt,
 405    diff_transforms:
 406        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 407    offset: usize,
 408    excerpt_offset: ExcerptDimension<usize>,
 409    buffer_offset: usize,
 410}
 411
 412#[derive(Clone, Debug)]
 413struct ExcerptIdMapping {
 414    id: ExcerptId,
 415    locator: Locator,
 416}
 417
 418/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 419/// These ranges are relative to the buffer itself
 420#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 421pub struct ExcerptRange<T> {
 422    /// The full range of text to be shown in the excerpt.
 423    pub context: Range<T>,
 424    /// The primary range of text to be highlighted in the excerpt.
 425    /// In a multi-buffer search, this would be the text that matched the search
 426    pub primary: Option<Range<T>>,
 427}
 428
 429#[derive(Clone, Debug, Default)]
 430pub struct ExcerptSummary {
 431    excerpt_id: ExcerptId,
 432    /// The location of the last [`Excerpt`] being summarized
 433    excerpt_locator: Locator,
 434    widest_line_number: u32,
 435    text: TextSummary,
 436}
 437
 438#[derive(Debug, Clone)]
 439pub struct DiffTransformSummary {
 440    input: TextSummary,
 441    output: TextSummary,
 442}
 443
 444#[derive(Clone)]
 445pub struct MultiBufferRows<'a> {
 446    point: Point,
 447    is_empty: bool,
 448    is_singleton: bool,
 449    cursor: MultiBufferCursor<'a, Point>,
 450}
 451
 452pub struct MultiBufferChunks<'a> {
 453    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 454    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 455    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 456    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 457    buffer_chunk: Option<Chunk<'a>>,
 458    range: Range<usize>,
 459    excerpt_offset_range: Range<ExcerptOffset>,
 460    excerpt_chunks: Option<ExcerptChunks<'a>>,
 461    language_aware: bool,
 462}
 463
 464pub struct ReversedMultiBufferChunks<'a> {
 465    cursor: MultiBufferCursor<'a, usize>,
 466    current_chunks: Option<rope::Chunks<'a>>,
 467    start: usize,
 468    offset: usize,
 469}
 470
 471pub struct MultiBufferBytes<'a> {
 472    range: Range<usize>,
 473    cursor: MultiBufferCursor<'a, usize>,
 474    excerpt_bytes: Option<text::Bytes<'a>>,
 475    has_trailing_newline: bool,
 476    chunk: &'a [u8],
 477}
 478
 479pub struct ReversedMultiBufferBytes<'a> {
 480    range: Range<usize>,
 481    chunks: ReversedMultiBufferChunks<'a>,
 482    chunk: &'a [u8],
 483}
 484
 485#[derive(Clone)]
 486struct MultiBufferCursor<'a, D: TextDimension> {
 487    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 488    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 489    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 490    cached_region: Option<MultiBufferRegion<'a, D>>,
 491}
 492
 493#[derive(Clone)]
 494struct MultiBufferRegion<'a, D: TextDimension> {
 495    buffer: &'a BufferSnapshot,
 496    is_main_buffer: bool,
 497    diff_hunk_status: Option<DiffHunkStatus>,
 498    excerpt: &'a Excerpt,
 499    buffer_range: Range<D>,
 500    range: Range<D>,
 501    has_trailing_newline: bool,
 502}
 503
 504struct ExcerptChunks<'a> {
 505    excerpt_id: ExcerptId,
 506    content_chunks: BufferChunks<'a>,
 507    footer_height: usize,
 508}
 509
 510#[derive(Debug)]
 511struct BufferEdit {
 512    range: Range<usize>,
 513    new_text: Arc<str>,
 514    is_insertion: bool,
 515    original_indent_column: Option<u32>,
 516    excerpt_id: ExcerptId,
 517}
 518
 519#[derive(Clone, Copy, Debug, PartialEq)]
 520enum DiffChangeKind {
 521    BufferEdited,
 522    DiffUpdated { base_changed: bool },
 523    ExpandOrCollapseHunks { expand: bool },
 524}
 525
 526#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 527pub enum ExpandExcerptDirection {
 528    Up,
 529    Down,
 530    UpAndDown,
 531}
 532
 533impl ExpandExcerptDirection {
 534    pub fn should_expand_up(&self) -> bool {
 535        match self {
 536            ExpandExcerptDirection::Up => true,
 537            ExpandExcerptDirection::Down => false,
 538            ExpandExcerptDirection::UpAndDown => true,
 539        }
 540    }
 541
 542    pub fn should_expand_down(&self) -> bool {
 543        match self {
 544            ExpandExcerptDirection::Up => false,
 545            ExpandExcerptDirection::Down => true,
 546            ExpandExcerptDirection::UpAndDown => true,
 547        }
 548    }
 549}
 550
 551#[derive(Clone, Debug, PartialEq)]
 552pub struct IndentGuide {
 553    pub buffer_id: BufferId,
 554    pub start_row: MultiBufferRow,
 555    pub end_row: MultiBufferRow,
 556    pub depth: u32,
 557    pub tab_size: u32,
 558    pub settings: IndentGuideSettings,
 559}
 560
 561impl IndentGuide {
 562    pub fn indent_level(&self) -> u32 {
 563        self.depth * self.tab_size
 564    }
 565}
 566
 567impl MultiBuffer {
 568    pub fn new(capability: Capability) -> Self {
 569        Self {
 570            snapshot: RefCell::new(MultiBufferSnapshot {
 571                show_headers: true,
 572                ..MultiBufferSnapshot::default()
 573            }),
 574            buffers: RefCell::default(),
 575            diffs: HashMap::default(),
 576            subscriptions: Topic::default(),
 577            singleton: false,
 578            capability,
 579            title: None,
 580            excerpts_by_path: Default::default(),
 581            paths_by_excerpt: Default::default(),
 582            buffer_changed_since_sync: Default::default(),
 583            history: History {
 584                next_transaction_id: clock::Lamport::default(),
 585                undo_stack: Vec::new(),
 586                redo_stack: Vec::new(),
 587                transaction_depth: 0,
 588                group_interval: Duration::from_millis(300),
 589            },
 590        }
 591    }
 592
 593    pub fn without_headers(capability: Capability) -> Self {
 594        Self {
 595            snapshot: Default::default(),
 596            buffers: Default::default(),
 597            excerpts_by_path: Default::default(),
 598            paths_by_excerpt: Default::default(),
 599            diffs: HashMap::default(),
 600            subscriptions: Default::default(),
 601            singleton: false,
 602            capability,
 603            buffer_changed_since_sync: Default::default(),
 604            history: History {
 605                next_transaction_id: Default::default(),
 606                undo_stack: Default::default(),
 607                redo_stack: Default::default(),
 608                transaction_depth: 0,
 609                group_interval: Duration::from_millis(300),
 610            },
 611            title: Default::default(),
 612        }
 613    }
 614
 615    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 616        let mut buffers = HashMap::default();
 617        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 618        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 619            buffer_state.buffer.update(new_cx, |buffer, _| {
 620                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 621            });
 622            buffers.insert(
 623                *buffer_id,
 624                BufferState {
 625                    buffer: buffer_state.buffer.clone(),
 626                    last_version: buffer_state.last_version.clone(),
 627                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 628                    excerpts: buffer_state.excerpts.clone(),
 629                    _subscriptions: [
 630                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 631                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 632                    ],
 633                },
 634            );
 635        }
 636        let mut diff_bases = HashMap::default();
 637        for (buffer_id, diff) in self.diffs.iter() {
 638            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 639        }
 640        Self {
 641            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 642            buffers: RefCell::new(buffers),
 643            excerpts_by_path: Default::default(),
 644            paths_by_excerpt: Default::default(),
 645            diffs: diff_bases,
 646            subscriptions: Default::default(),
 647            singleton: self.singleton,
 648            capability: self.capability,
 649            history: self.history.clone(),
 650            title: self.title.clone(),
 651            buffer_changed_since_sync,
 652        }
 653    }
 654
 655    pub fn with_title(mut self, title: String) -> Self {
 656        self.title = Some(title);
 657        self
 658    }
 659
 660    pub fn read_only(&self) -> bool {
 661        self.capability == Capability::ReadOnly
 662    }
 663
 664    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 665        let mut this = Self::new(buffer.read(cx).capability());
 666        this.singleton = true;
 667        this.push_excerpts(
 668            buffer,
 669            [ExcerptRange {
 670                context: text::Anchor::MIN..text::Anchor::MAX,
 671                primary: None,
 672            }],
 673            cx,
 674        );
 675        this.snapshot.borrow_mut().singleton = true;
 676        this
 677    }
 678
 679    /// Returns an up-to-date snapshot of the MultiBuffer.
 680    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 681        self.sync(cx);
 682        self.snapshot.borrow().clone()
 683    }
 684
 685    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 686        self.sync(cx);
 687        self.snapshot.borrow()
 688    }
 689
 690    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 691        if self.singleton {
 692            return Some(
 693                self.buffers
 694                    .borrow()
 695                    .values()
 696                    .next()
 697                    .unwrap()
 698                    .buffer
 699                    .clone(),
 700            );
 701        } else {
 702            None
 703        }
 704    }
 705
 706    pub fn is_singleton(&self) -> bool {
 707        self.singleton
 708    }
 709
 710    pub fn subscribe(&mut self) -> Subscription {
 711        self.subscriptions.subscribe()
 712    }
 713
 714    pub fn is_dirty(&self, cx: &App) -> bool {
 715        self.read(cx).is_dirty()
 716    }
 717
 718    pub fn has_deleted_file(&self, cx: &App) -> bool {
 719        self.read(cx).has_deleted_file()
 720    }
 721
 722    pub fn has_conflict(&self, cx: &App) -> bool {
 723        self.read(cx).has_conflict()
 724    }
 725
 726    // The `is_empty` signature doesn't match what clippy expects
 727    #[allow(clippy::len_without_is_empty)]
 728    pub fn len(&self, cx: &App) -> usize {
 729        self.read(cx).len()
 730    }
 731
 732    pub fn is_empty(&self) -> bool {
 733        self.buffers.borrow().is_empty()
 734    }
 735
 736    pub fn symbols_containing<T: ToOffset>(
 737        &self,
 738        offset: T,
 739        theme: Option<&SyntaxTheme>,
 740        cx: &App,
 741    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 742        self.read(cx).symbols_containing(offset, theme)
 743    }
 744
 745    pub fn edit<I, S, T>(
 746        &self,
 747        edits: I,
 748        autoindent_mode: Option<AutoindentMode>,
 749        cx: &mut Context<Self>,
 750    ) where
 751        I: IntoIterator<Item = (Range<S>, T)>,
 752        S: ToOffset,
 753        T: Into<Arc<str>>,
 754    {
 755        let snapshot = self.read(cx);
 756        let edits = edits
 757            .into_iter()
 758            .map(|(range, new_text)| {
 759                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 760                if range.start > range.end {
 761                    mem::swap(&mut range.start, &mut range.end);
 762                }
 763                (range, new_text.into())
 764            })
 765            .collect::<Vec<_>>();
 766
 767        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 768
 769        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 770        fn edit_internal(
 771            this: &MultiBuffer,
 772            snapshot: Ref<MultiBufferSnapshot>,
 773            edits: Vec<(Range<usize>, Arc<str>)>,
 774            mut autoindent_mode: Option<AutoindentMode>,
 775            cx: &mut Context<MultiBuffer>,
 776        ) {
 777            if this.read_only() || this.buffers.borrow().is_empty() {
 778                return;
 779            }
 780
 781            let original_indent_columns = match &mut autoindent_mode {
 782                Some(AutoindentMode::Block {
 783                    original_indent_columns,
 784                }) => mem::take(original_indent_columns),
 785                _ => Default::default(),
 786            };
 787
 788            let (buffer_edits, edited_excerpt_ids) =
 789                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 790            drop(snapshot);
 791
 792            let mut buffer_ids = Vec::new();
 793            for (buffer_id, mut edits) in buffer_edits {
 794                buffer_ids.push(buffer_id);
 795                edits.sort_by_key(|edit| edit.range.start);
 796                this.buffers.borrow()[&buffer_id]
 797                    .buffer
 798                    .update(cx, |buffer, cx| {
 799                        let mut edits = edits.into_iter().peekable();
 800                        let mut insertions = Vec::new();
 801                        let mut original_indent_columns = Vec::new();
 802                        let mut deletions = Vec::new();
 803                        let empty_str: Arc<str> = Arc::default();
 804                        while let Some(BufferEdit {
 805                            mut range,
 806                            mut new_text,
 807                            mut is_insertion,
 808                            original_indent_column,
 809                            excerpt_id,
 810                        }) = edits.next()
 811                        {
 812                            while let Some(BufferEdit {
 813                                range: next_range,
 814                                is_insertion: next_is_insertion,
 815                                new_text: next_new_text,
 816                                excerpt_id: next_excerpt_id,
 817                                ..
 818                            }) = edits.peek()
 819                            {
 820                                if range.end >= next_range.start {
 821                                    range.end = cmp::max(next_range.end, range.end);
 822                                    is_insertion |= *next_is_insertion;
 823                                    if excerpt_id == *next_excerpt_id {
 824                                        new_text = format!("{new_text}{next_new_text}").into();
 825                                    }
 826                                    edits.next();
 827                                } else {
 828                                    break;
 829                                }
 830                            }
 831
 832                            if is_insertion {
 833                                original_indent_columns.push(original_indent_column);
 834                                insertions.push((
 835                                    buffer.anchor_before(range.start)
 836                                        ..buffer.anchor_before(range.end),
 837                                    new_text.clone(),
 838                                ));
 839                            } else if !range.is_empty() {
 840                                deletions.push((
 841                                    buffer.anchor_before(range.start)
 842                                        ..buffer.anchor_before(range.end),
 843                                    empty_str.clone(),
 844                                ));
 845                            }
 846                        }
 847
 848                        let deletion_autoindent_mode =
 849                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 850                                Some(AutoindentMode::Block {
 851                                    original_indent_columns: Default::default(),
 852                                })
 853                            } else {
 854                                autoindent_mode.clone()
 855                            };
 856                        let insertion_autoindent_mode =
 857                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 858                                Some(AutoindentMode::Block {
 859                                    original_indent_columns,
 860                                })
 861                            } else {
 862                                autoindent_mode.clone()
 863                            };
 864
 865                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 866                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 867                    })
 868            }
 869
 870            cx.emit(Event::ExcerptsEdited {
 871                excerpt_ids: edited_excerpt_ids,
 872                buffer_ids,
 873            });
 874        }
 875    }
 876
 877    fn convert_edits_to_buffer_edits(
 878        &self,
 879        edits: Vec<(Range<usize>, Arc<str>)>,
 880        snapshot: &MultiBufferSnapshot,
 881        original_indent_columns: &[Option<u32>],
 882    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 883        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 884        let mut edited_excerpt_ids = Vec::new();
 885        let mut cursor = snapshot.cursor::<usize>();
 886        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 887            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 888
 889            cursor.seek(&range.start);
 890            let mut start_region = cursor.region().expect("start offset out of bounds");
 891            if !start_region.is_main_buffer {
 892                cursor.next();
 893                if let Some(region) = cursor.region() {
 894                    start_region = region;
 895                } else {
 896                    continue;
 897                }
 898            }
 899
 900            if range.end < start_region.range.start {
 901                continue;
 902            }
 903
 904            if range.end > start_region.range.end {
 905                cursor.seek_forward(&range.end);
 906            }
 907            let mut end_region = cursor.region().expect("end offset out of bounds");
 908            if !end_region.is_main_buffer {
 909                cursor.prev();
 910                if let Some(region) = cursor.region() {
 911                    end_region = region;
 912                } else {
 913                    continue;
 914                }
 915            }
 916
 917            if range.start > end_region.range.end {
 918                continue;
 919            }
 920
 921            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 922            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 923            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 924                .min(start_region.buffer_range.end);
 925            let buffer_end =
 926                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 927
 928            if start_region.excerpt.id == end_region.excerpt.id {
 929                if start_region.is_main_buffer {
 930                    edited_excerpt_ids.push(start_region.excerpt.id);
 931                    buffer_edits
 932                        .entry(start_region.buffer.remote_id())
 933                        .or_default()
 934                        .push(BufferEdit {
 935                            range: buffer_start..buffer_end,
 936                            new_text,
 937                            is_insertion: true,
 938                            original_indent_column,
 939                            excerpt_id: start_region.excerpt.id,
 940                        });
 941                }
 942            } else {
 943                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 944                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 945                if start_region.is_main_buffer {
 946                    edited_excerpt_ids.push(start_region.excerpt.id);
 947                    buffer_edits
 948                        .entry(start_region.buffer.remote_id())
 949                        .or_default()
 950                        .push(BufferEdit {
 951                            range: start_excerpt_range,
 952                            new_text: new_text.clone(),
 953                            is_insertion: true,
 954                            original_indent_column,
 955                            excerpt_id: start_region.excerpt.id,
 956                        });
 957                }
 958                if end_region.is_main_buffer {
 959                    edited_excerpt_ids.push(end_region.excerpt.id);
 960                    buffer_edits
 961                        .entry(end_region.buffer.remote_id())
 962                        .or_default()
 963                        .push(BufferEdit {
 964                            range: end_excerpt_range,
 965                            new_text: new_text.clone(),
 966                            is_insertion: false,
 967                            original_indent_column,
 968                            excerpt_id: end_region.excerpt.id,
 969                        });
 970                }
 971
 972                cursor.seek(&range.start);
 973                cursor.next_excerpt();
 974                while let Some(region) = cursor.region() {
 975                    if region.excerpt.id == end_region.excerpt.id {
 976                        break;
 977                    }
 978                    if region.is_main_buffer {
 979                        edited_excerpt_ids.push(region.excerpt.id);
 980                        buffer_edits
 981                            .entry(region.buffer.remote_id())
 982                            .or_default()
 983                            .push(BufferEdit {
 984                                range: region.buffer_range,
 985                                new_text: new_text.clone(),
 986                                is_insertion: false,
 987                                original_indent_column,
 988                                excerpt_id: region.excerpt.id,
 989                            });
 990                    }
 991                    cursor.next_excerpt();
 992                }
 993            }
 994        }
 995        (buffer_edits, edited_excerpt_ids)
 996    }
 997
 998    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 999    where
1000        I: IntoIterator<Item = Range<S>>,
1001        S: ToOffset,
1002    {
1003        let snapshot = self.read(cx);
1004        let empty = Arc::<str>::from("");
1005        let edits = ranges
1006            .into_iter()
1007            .map(|range| {
1008                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1009                if range.start > range.end {
1010                    mem::swap(&mut range.start, &mut range.end);
1011                }
1012                (range, empty.clone())
1013            })
1014            .collect::<Vec<_>>();
1015
1016        return autoindent_ranges_internal(self, snapshot, edits, cx);
1017
1018        fn autoindent_ranges_internal(
1019            this: &MultiBuffer,
1020            snapshot: Ref<MultiBufferSnapshot>,
1021            edits: Vec<(Range<usize>, Arc<str>)>,
1022            cx: &mut Context<MultiBuffer>,
1023        ) {
1024            if this.read_only() || this.buffers.borrow().is_empty() {
1025                return;
1026            }
1027
1028            let (buffer_edits, edited_excerpt_ids) =
1029                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1030            drop(snapshot);
1031
1032            let mut buffer_ids = Vec::new();
1033            for (buffer_id, mut edits) in buffer_edits {
1034                buffer_ids.push(buffer_id);
1035                edits.sort_unstable_by_key(|edit| edit.range.start);
1036
1037                let mut ranges: Vec<Range<usize>> = Vec::new();
1038                for edit in edits {
1039                    if let Some(last_range) = ranges.last_mut() {
1040                        if edit.range.start <= last_range.end {
1041                            last_range.end = last_range.end.max(edit.range.end);
1042                            continue;
1043                        }
1044                    }
1045                    ranges.push(edit.range);
1046                }
1047
1048                this.buffers.borrow()[&buffer_id]
1049                    .buffer
1050                    .update(cx, |buffer, cx| {
1051                        buffer.autoindent_ranges(ranges, cx);
1052                    })
1053            }
1054
1055            cx.emit(Event::ExcerptsEdited {
1056                excerpt_ids: edited_excerpt_ids,
1057                buffer_ids,
1058            });
1059        }
1060    }
1061
1062    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1063    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1064    // Panics if the given position is invalid.
1065    pub fn insert_empty_line(
1066        &mut self,
1067        position: impl ToPoint,
1068        space_above: bool,
1069        space_below: bool,
1070        cx: &mut Context<Self>,
1071    ) -> Point {
1072        let multibuffer_point = position.to_point(&self.read(cx));
1073        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1074        self.start_transaction(cx);
1075        let empty_line_start = buffer.update(cx, |buffer, cx| {
1076            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1077        });
1078        self.end_transaction(cx);
1079        multibuffer_point + (empty_line_start - buffer_point)
1080    }
1081
1082    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1083        self.start_transaction_at(Instant::now(), cx)
1084    }
1085
1086    pub fn start_transaction_at(
1087        &mut self,
1088        now: Instant,
1089        cx: &mut Context<Self>,
1090    ) -> Option<TransactionId> {
1091        if let Some(buffer) = self.as_singleton() {
1092            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1093        }
1094
1095        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1096            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1097        }
1098        self.history.start_transaction(now)
1099    }
1100
1101    pub fn last_transaction_id(&self) -> Option<TransactionId> {
1102        let last_transaction = self.history.undo_stack.last()?;
1103        return Some(last_transaction.id);
1104    }
1105
1106    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1107        self.end_transaction_at(Instant::now(), cx)
1108    }
1109
1110    pub fn end_transaction_at(
1111        &mut self,
1112        now: Instant,
1113        cx: &mut Context<Self>,
1114    ) -> Option<TransactionId> {
1115        if let Some(buffer) = self.as_singleton() {
1116            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1117        }
1118
1119        let mut buffer_transactions = HashMap::default();
1120        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1121            if let Some(transaction_id) =
1122                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1123            {
1124                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1125            }
1126        }
1127
1128        if self.history.end_transaction(now, buffer_transactions) {
1129            let transaction_id = self.history.group().unwrap();
1130            Some(transaction_id)
1131        } else {
1132            None
1133        }
1134    }
1135
1136    pub fn edited_ranges_for_transaction<D>(
1137        &self,
1138        transaction_id: TransactionId,
1139        cx: &App,
1140    ) -> Vec<Range<D>>
1141    where
1142        D: TextDimension + Ord + Sub<D, Output = D>,
1143    {
1144        let Some(transaction) = self.history.transaction(transaction_id) else {
1145            return Vec::new();
1146        };
1147
1148        let mut ranges = Vec::new();
1149        let snapshot = self.read(cx);
1150        let buffers = self.buffers.borrow();
1151        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1152
1153        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1154            let Some(buffer_state) = buffers.get(buffer_id) else {
1155                continue;
1156            };
1157
1158            let buffer = buffer_state.buffer.read(cx);
1159            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1160                for excerpt_id in &buffer_state.excerpts {
1161                    cursor.seek(excerpt_id, Bias::Left, &());
1162                    if let Some(excerpt) = cursor.item() {
1163                        if excerpt.locator == *excerpt_id {
1164                            let excerpt_buffer_start =
1165                                excerpt.range.context.start.summary::<D>(buffer);
1166                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1167                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1168                            if excerpt_range.contains(&range.start)
1169                                && excerpt_range.contains(&range.end)
1170                            {
1171                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1172
1173                                let mut start = excerpt_start;
1174                                start.add_assign(&(range.start - excerpt_buffer_start));
1175                                let mut end = excerpt_start;
1176                                end.add_assign(&(range.end - excerpt_buffer_start));
1177
1178                                ranges.push(start..end);
1179                                break;
1180                            }
1181                        }
1182                    }
1183                }
1184            }
1185        }
1186
1187        ranges.sort_by_key(|range| range.start);
1188        ranges
1189    }
1190
1191    pub fn merge_transactions(
1192        &mut self,
1193        transaction: TransactionId,
1194        destination: TransactionId,
1195        cx: &mut Context<Self>,
1196    ) {
1197        if let Some(buffer) = self.as_singleton() {
1198            buffer.update(cx, |buffer, _| {
1199                buffer.merge_transactions(transaction, destination)
1200            });
1201        } else if let Some(transaction) = self.history.forget(transaction) {
1202            if let Some(destination) = self.history.transaction_mut(destination) {
1203                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1204                    if let Some(destination_buffer_transaction_id) =
1205                        destination.buffer_transactions.get(&buffer_id)
1206                    {
1207                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1208                            state.buffer.update(cx, |buffer, _| {
1209                                buffer.merge_transactions(
1210                                    buffer_transaction_id,
1211                                    *destination_buffer_transaction_id,
1212                                )
1213                            });
1214                        }
1215                    } else {
1216                        destination
1217                            .buffer_transactions
1218                            .insert(buffer_id, buffer_transaction_id);
1219                    }
1220                }
1221            }
1222        }
1223    }
1224
1225    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1226        self.history.finalize_last_transaction();
1227        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1228            buffer.update(cx, |buffer, _| {
1229                buffer.finalize_last_transaction();
1230            });
1231        }
1232    }
1233
1234    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1235    where
1236        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1237    {
1238        self.history
1239            .push_transaction(buffer_transactions, Instant::now(), cx);
1240        self.history.finalize_last_transaction();
1241    }
1242
1243    pub fn group_until_transaction(
1244        &mut self,
1245        transaction_id: TransactionId,
1246        cx: &mut Context<Self>,
1247    ) {
1248        if let Some(buffer) = self.as_singleton() {
1249            buffer.update(cx, |buffer, _| {
1250                buffer.group_until_transaction(transaction_id)
1251            });
1252        } else {
1253            self.history.group_until(transaction_id);
1254        }
1255    }
1256
1257    pub fn set_active_selections(
1258        &self,
1259        selections: &[Selection<Anchor>],
1260        line_mode: bool,
1261        cursor_shape: CursorShape,
1262        cx: &mut Context<Self>,
1263    ) {
1264        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1265            Default::default();
1266        let snapshot = self.read(cx);
1267        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1268        for selection in selections {
1269            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1270            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1271
1272            cursor.seek(&Some(start_locator), Bias::Left, &());
1273            while let Some(excerpt) = cursor.item() {
1274                if excerpt.locator > *end_locator {
1275                    break;
1276                }
1277
1278                let mut start = excerpt.range.context.start;
1279                let mut end = excerpt.range.context.end;
1280                if excerpt.id == selection.start.excerpt_id {
1281                    start = selection.start.text_anchor;
1282                }
1283                if excerpt.id == selection.end.excerpt_id {
1284                    end = selection.end.text_anchor;
1285                }
1286                selections_by_buffer
1287                    .entry(excerpt.buffer_id)
1288                    .or_default()
1289                    .push(Selection {
1290                        id: selection.id,
1291                        start,
1292                        end,
1293                        reversed: selection.reversed,
1294                        goal: selection.goal,
1295                    });
1296
1297                cursor.next(&());
1298            }
1299        }
1300
1301        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1302            if !selections_by_buffer.contains_key(buffer_id) {
1303                buffer_state
1304                    .buffer
1305                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1306            }
1307        }
1308
1309        for (buffer_id, mut selections) in selections_by_buffer {
1310            self.buffers.borrow()[&buffer_id]
1311                .buffer
1312                .update(cx, |buffer, cx| {
1313                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1314                    let mut selections = selections.into_iter().peekable();
1315                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1316                        let mut selection = selections.next()?;
1317                        while let Some(next_selection) = selections.peek() {
1318                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1319                                let next_selection = selections.next().unwrap();
1320                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1321                                    selection.end = next_selection.end;
1322                                }
1323                            } else {
1324                                break;
1325                            }
1326                        }
1327                        Some(selection)
1328                    }));
1329                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1330                });
1331        }
1332    }
1333
1334    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1335        for buffer in self.buffers.borrow().values() {
1336            buffer
1337                .buffer
1338                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1339        }
1340    }
1341
1342    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1343        let mut transaction_id = None;
1344        if let Some(buffer) = self.as_singleton() {
1345            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1346        } else {
1347            while let Some(transaction) = self.history.pop_undo() {
1348                let mut undone = false;
1349                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1350                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1351                        undone |= buffer.update(cx, |buffer, cx| {
1352                            let undo_to = *buffer_transaction_id;
1353                            if let Some(entry) = buffer.peek_undo_stack() {
1354                                *buffer_transaction_id = entry.transaction_id();
1355                            }
1356                            buffer.undo_to_transaction(undo_to, cx)
1357                        });
1358                    }
1359                }
1360
1361                if undone {
1362                    transaction_id = Some(transaction.id);
1363                    break;
1364                }
1365            }
1366        }
1367
1368        if let Some(transaction_id) = transaction_id {
1369            cx.emit(Event::TransactionUndone { transaction_id });
1370        }
1371
1372        transaction_id
1373    }
1374
1375    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1376        if let Some(buffer) = self.as_singleton() {
1377            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1378        }
1379
1380        while let Some(transaction) = self.history.pop_redo() {
1381            let mut redone = false;
1382            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1383                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1384                    redone |= buffer.update(cx, |buffer, cx| {
1385                        let redo_to = *buffer_transaction_id;
1386                        if let Some(entry) = buffer.peek_redo_stack() {
1387                            *buffer_transaction_id = entry.transaction_id();
1388                        }
1389                        buffer.redo_to_transaction(redo_to, cx)
1390                    });
1391                }
1392            }
1393
1394            if redone {
1395                return Some(transaction.id);
1396            }
1397        }
1398
1399        None
1400    }
1401
1402    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1403        if let Some(buffer) = self.as_singleton() {
1404            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1405        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1406            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1407                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1408                    buffer.update(cx, |buffer, cx| {
1409                        buffer.undo_transaction(*transaction_id, cx)
1410                    });
1411                }
1412            }
1413        }
1414    }
1415
1416    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1417        if let Some(buffer) = self.as_singleton() {
1418            buffer.update(cx, |buffer, _| {
1419                buffer.forget_transaction(transaction_id);
1420            });
1421        } else if let Some(transaction) = self.history.forget(transaction_id) {
1422            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1423                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1424                    state.buffer.update(cx, |buffer, _| {
1425                        buffer.forget_transaction(buffer_transaction_id);
1426                    });
1427                }
1428            }
1429        }
1430    }
1431
1432    pub fn push_excerpts<O>(
1433        &mut self,
1434        buffer: Entity<Buffer>,
1435        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1436        cx: &mut Context<Self>,
1437    ) -> Vec<ExcerptId>
1438    where
1439        O: text::ToOffset,
1440    {
1441        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1442    }
1443
1444    pub fn push_excerpts_with_context_lines<O>(
1445        &mut self,
1446        buffer: Entity<Buffer>,
1447        ranges: Vec<Range<O>>,
1448        context_line_count: u32,
1449        cx: &mut Context<Self>,
1450    ) -> Vec<Range<Anchor>>
1451    where
1452        O: text::ToPoint + text::ToOffset,
1453    {
1454        let buffer_id = buffer.read(cx).remote_id();
1455        let buffer_snapshot = buffer.read(cx).snapshot();
1456        let (excerpt_ranges, range_counts) =
1457            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1458
1459        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1460
1461        let mut anchor_ranges = Vec::new();
1462        let mut ranges = ranges.into_iter();
1463        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1464            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1465                let start = Anchor {
1466                    buffer_id: Some(buffer_id),
1467                    excerpt_id,
1468                    text_anchor: buffer_snapshot.anchor_after(range.start),
1469                    diff_base_anchor: None,
1470                };
1471                let end = Anchor {
1472                    buffer_id: Some(buffer_id),
1473                    excerpt_id,
1474                    text_anchor: buffer_snapshot.anchor_after(range.end),
1475                    diff_base_anchor: None,
1476                };
1477                start..end
1478            }))
1479        }
1480        anchor_ranges
1481    }
1482
1483    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1484        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1485        let snapshot = self.snapshot(cx);
1486        let excerpt = snapshot.excerpt(*excerpt_id)?;
1487        Some(Anchor::in_buffer(
1488            *excerpt_id,
1489            excerpt.buffer_id,
1490            excerpt.range.context.start,
1491        ))
1492    }
1493
1494    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1495        self.excerpts_by_path.keys()
1496    }
1497
1498    fn expand_excerpts_with_paths(
1499        &mut self,
1500        ids: impl IntoIterator<Item = ExcerptId>,
1501        line_count: u32,
1502        direction: ExpandExcerptDirection,
1503        cx: &mut Context<Self>,
1504    ) {
1505        let grouped = ids
1506            .into_iter()
1507            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1508            .into_iter()
1509            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1510            .collect::<Vec<_>>();
1511        let snapshot = self.snapshot(cx);
1512
1513        for (path, ids) in grouped.into_iter() {
1514            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1515                continue;
1516            };
1517
1518            let ids_to_expand = HashSet::from_iter(ids);
1519            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1520                let excerpt = snapshot.excerpt(*excerpt_id)?;
1521
1522                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1523                if ids_to_expand.contains(excerpt_id) {
1524                    match direction {
1525                        ExpandExcerptDirection::Up => {
1526                            context.start.row = context.start.row.saturating_sub(line_count);
1527                            context.start.column = 0;
1528                        }
1529                        ExpandExcerptDirection::Down => {
1530                            context.end.row =
1531                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1532                            context.end.column = excerpt.buffer.line_len(context.end.row);
1533                        }
1534                        ExpandExcerptDirection::UpAndDown => {
1535                            context.start.row = context.start.row.saturating_sub(line_count);
1536                            context.start.column = 0;
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                    }
1542                }
1543
1544                Some(ExcerptRange {
1545                    context,
1546                    primary: excerpt
1547                        .range
1548                        .primary
1549                        .as_ref()
1550                        .map(|range| range.to_point(&excerpt.buffer)),
1551                })
1552            });
1553            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1554            for range in expanded_ranges {
1555                if let Some(last_range) = merged_ranges.last_mut() {
1556                    if last_range.context.end >= range.context.start {
1557                        last_range.context.end = range.context.end;
1558                        continue;
1559                    }
1560                }
1561                merged_ranges.push(range)
1562            }
1563            let Some(excerpt_id) = excerpt_ids.first() else {
1564                continue;
1565            };
1566            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1567                continue;
1568            };
1569
1570            let Some(buffer) = self
1571                .buffers
1572                .borrow()
1573                .get(buffer_id)
1574                .map(|b| b.buffer.clone())
1575            else {
1576                continue;
1577            };
1578
1579            let buffer_snapshot = buffer.read(cx).snapshot();
1580            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1581        }
1582    }
1583
1584    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1585    pub fn set_excerpts_for_path(
1586        &mut self,
1587        path: PathKey,
1588        buffer: Entity<Buffer>,
1589        ranges: Vec<Range<Point>>,
1590        context_line_count: u32,
1591        cx: &mut Context<Self>,
1592    ) -> bool {
1593        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1594
1595        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1596        self.update_path_excerpts(path, buffer, &buffer_snapshot, new, cx)
1597    }
1598
1599    fn update_path_excerpts(
1600        &mut self,
1601        path: PathKey,
1602        buffer: Entity<Buffer>,
1603        buffer_snapshot: &BufferSnapshot,
1604        new: Vec<ExcerptRange<Point>>,
1605        cx: &mut Context<Self>,
1606    ) -> bool {
1607        let mut insert_after = self
1608            .excerpts_by_path
1609            .range(..path.clone())
1610            .next_back()
1611            .map(|(_, value)| *value.last().unwrap())
1612            .unwrap_or(ExcerptId::min());
1613
1614        let existing = self
1615            .excerpts_by_path
1616            .get(&path)
1617            .cloned()
1618            .unwrap_or_default();
1619
1620        let mut new_iter = new.into_iter().peekable();
1621        let mut existing_iter = existing.into_iter().peekable();
1622
1623        let mut new_excerpt_ids = Vec::new();
1624        let mut to_remove = Vec::new();
1625        let mut to_insert = Vec::new();
1626        let mut added_a_new_excerpt = false;
1627        let snapshot = self.snapshot(cx);
1628
1629        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1630        excerpts_cursor.next(&());
1631
1632        loop {
1633            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1634                (Some(new), Some(existing)) => (new, existing),
1635                (None, None) => break,
1636                (None, Some(_)) => {
1637                    to_remove.push(existing_iter.next().unwrap());
1638                    continue;
1639                }
1640                (Some(_), None) => {
1641                    added_a_new_excerpt = true;
1642                    to_insert.push(new_iter.next().unwrap());
1643                    continue;
1644                }
1645            };
1646            let locator = snapshot.excerpt_locator_for_id(*existing);
1647            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1648            let Some(existing_excerpt) = excerpts_cursor.item() else {
1649                to_remove.push(existing_iter.next().unwrap());
1650                to_insert.push(new_iter.next().unwrap());
1651                continue;
1652            };
1653            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1654                to_remove.push(existing_iter.next().unwrap());
1655                to_insert.push(new_iter.next().unwrap());
1656                continue;
1657            }
1658
1659            let existing_start = existing_excerpt
1660                .range
1661                .context
1662                .start
1663                .to_point(&buffer_snapshot);
1664            let existing_end = existing_excerpt
1665                .range
1666                .context
1667                .end
1668                .to_point(&buffer_snapshot);
1669
1670            if existing_end < new.context.start {
1671                to_remove.push(existing_iter.next().unwrap());
1672                continue;
1673            } else if existing_start > new.context.end {
1674                to_insert.push(new_iter.next().unwrap());
1675                continue;
1676            }
1677
1678            // maybe merge overlapping excerpts?
1679            // it's hard to distinguish between a manually expanded excerpt, and one that
1680            // got smaller because of a missing diff.
1681            if existing_start == new.context.start && existing_end == new.context.end {
1682                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1683                    insert_after,
1684                    buffer.clone(),
1685                    mem::take(&mut to_insert),
1686                    cx,
1687                ));
1688                insert_after = existing_iter.next().unwrap();
1689                new_excerpt_ids.push(insert_after);
1690                new_iter.next();
1691            } else {
1692                to_remove.push(existing_iter.next().unwrap());
1693                to_insert.push(new_iter.next().unwrap());
1694            }
1695        }
1696
1697        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1698            insert_after,
1699            buffer,
1700            to_insert,
1701            cx,
1702        ));
1703        self.remove_excerpts(to_remove, cx);
1704        if new_excerpt_ids.is_empty() {
1705            self.excerpts_by_path.remove(&path);
1706        } else {
1707            for excerpt_id in &new_excerpt_ids {
1708                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1709            }
1710            self.excerpts_by_path.insert(path, new_excerpt_ids);
1711        }
1712
1713        added_a_new_excerpt
1714    }
1715
1716    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1717        self.excerpts_by_path.keys().cloned()
1718    }
1719
1720    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1721        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1722            self.remove_excerpts(to_remove, cx)
1723        }
1724    }
1725
1726    pub fn push_multiple_excerpts_with_context_lines(
1727        &self,
1728        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1729        context_line_count: u32,
1730        cx: &mut Context<Self>,
1731    ) -> Task<Vec<Range<Anchor>>> {
1732        use futures::StreamExt;
1733
1734        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1735
1736        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1737
1738        for (buffer, ranges) in buffers_with_ranges {
1739            let (buffer_id, buffer_snapshot) =
1740                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1741
1742            buffer_ids.push(buffer_id);
1743
1744            cx.background_spawn({
1745                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1746
1747                async move {
1748                    let (excerpt_ranges, counts) =
1749                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1750                    excerpt_ranges_tx
1751                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1752                        .await
1753                        .ok();
1754                }
1755            })
1756            .detach()
1757        }
1758
1759        cx.spawn(async move |this, cx| {
1760            let mut results_by_buffer_id = HashMap::default();
1761            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1762                excerpt_ranges_rx.next().await
1763            {
1764                results_by_buffer_id
1765                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1766            }
1767
1768            let mut multi_buffer_ranges = Vec::default();
1769            'outer: for buffer_id in buffer_ids {
1770                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1771                    results_by_buffer_id.remove(&buffer_id)
1772                else {
1773                    continue;
1774                };
1775
1776                let mut ranges = ranges.into_iter();
1777                let mut range_counts = range_counts.into_iter();
1778                for excerpt_ranges in excerpt_ranges.chunks(100) {
1779                    let excerpt_ids = match this.update(cx, |this, cx| {
1780                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1781                    }) {
1782                        Ok(excerpt_ids) => excerpt_ids,
1783                        Err(_) => continue 'outer,
1784                    };
1785
1786                    for (excerpt_id, range_count) in
1787                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1788                    {
1789                        for range in ranges.by_ref().take(range_count) {
1790                            let start = Anchor {
1791                                buffer_id: Some(buffer_id),
1792                                excerpt_id,
1793                                text_anchor: range.start,
1794                                diff_base_anchor: None,
1795                            };
1796                            let end = Anchor {
1797                                buffer_id: Some(buffer_id),
1798                                excerpt_id,
1799                                text_anchor: range.end,
1800                                diff_base_anchor: None,
1801                            };
1802                            multi_buffer_ranges.push(start..end);
1803                        }
1804                    }
1805                }
1806            }
1807
1808            multi_buffer_ranges
1809        })
1810    }
1811
1812    pub fn insert_excerpts_after<O>(
1813        &mut self,
1814        prev_excerpt_id: ExcerptId,
1815        buffer: Entity<Buffer>,
1816        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1817        cx: &mut Context<Self>,
1818    ) -> Vec<ExcerptId>
1819    where
1820        O: text::ToOffset,
1821    {
1822        let mut ids = Vec::new();
1823        let mut next_excerpt_id =
1824            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1825                last_entry.id.0 + 1
1826            } else {
1827                1
1828            };
1829        self.insert_excerpts_with_ids_after(
1830            prev_excerpt_id,
1831            buffer,
1832            ranges.into_iter().map(|range| {
1833                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1834                ids.push(id);
1835                (id, range)
1836            }),
1837            cx,
1838        );
1839        ids
1840    }
1841
1842    pub fn insert_excerpts_with_ids_after<O>(
1843        &mut self,
1844        prev_excerpt_id: ExcerptId,
1845        buffer: Entity<Buffer>,
1846        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1847        cx: &mut Context<Self>,
1848    ) where
1849        O: text::ToOffset,
1850    {
1851        assert_eq!(self.history.transaction_depth, 0);
1852        let mut ranges = ranges.into_iter().peekable();
1853        if ranges.peek().is_none() {
1854            return Default::default();
1855        }
1856
1857        self.sync(cx);
1858
1859        let buffer_snapshot = buffer.read(cx).snapshot();
1860        let buffer_id = buffer_snapshot.remote_id();
1861
1862        let mut buffers = self.buffers.borrow_mut();
1863        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1864            self.buffer_changed_since_sync.replace(true);
1865            buffer.update(cx, |buffer, _| {
1866                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1867            });
1868            BufferState {
1869                last_version: buffer_snapshot.version().clone(),
1870                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1871                excerpts: Default::default(),
1872                _subscriptions: [
1873                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1874                    cx.subscribe(&buffer, Self::on_buffer_event),
1875                ],
1876                buffer: buffer.clone(),
1877            }
1878        });
1879
1880        let mut snapshot = self.snapshot.borrow_mut();
1881
1882        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1883        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1884        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1885        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1886        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1887
1888        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1889        new_excerpts.update_last(
1890            |excerpt| {
1891                excerpt.has_trailing_newline = true;
1892            },
1893            &(),
1894        );
1895
1896        let next_locator = if let Some(excerpt) = cursor.item() {
1897            excerpt.locator.clone()
1898        } else {
1899            Locator::max()
1900        };
1901
1902        let mut excerpts = Vec::new();
1903        while let Some((id, range)) = ranges.next() {
1904            let locator = Locator::between(&prev_locator, &next_locator);
1905            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1906                buffer_state.excerpts.insert(ix, locator.clone());
1907            }
1908            let range = ExcerptRange {
1909                context: buffer_snapshot.anchor_before(&range.context.start)
1910                    ..buffer_snapshot.anchor_after(&range.context.end),
1911                primary: range.primary.map(|primary| {
1912                    buffer_snapshot.anchor_before(&primary.start)
1913                        ..buffer_snapshot.anchor_after(&primary.end)
1914                }),
1915            };
1916            excerpts.push((id, range.clone()));
1917            let excerpt = Excerpt::new(
1918                id,
1919                locator.clone(),
1920                buffer_id,
1921                buffer_snapshot.clone(),
1922                range,
1923                ranges.peek().is_some() || cursor.item().is_some(),
1924            );
1925            new_excerpts.push(excerpt, &());
1926            prev_locator = locator.clone();
1927
1928            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1929                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1930            }
1931            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1932        }
1933
1934        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1935
1936        let suffix = cursor.suffix(&());
1937        let changed_trailing_excerpt = suffix.is_empty();
1938        new_excerpts.append(suffix, &());
1939        drop(cursor);
1940        snapshot.excerpts = new_excerpts;
1941        snapshot.excerpt_ids = new_excerpt_ids;
1942        if changed_trailing_excerpt {
1943            snapshot.trailing_excerpt_update_count += 1;
1944        }
1945
1946        self.sync_diff_transforms(
1947            &mut snapshot,
1948            vec![Edit {
1949                old: edit_start..edit_start,
1950                new: edit_start..edit_end,
1951            }],
1952            DiffChangeKind::BufferEdited,
1953        );
1954        cx.emit(Event::Edited {
1955            singleton_buffer_edited: false,
1956            edited_buffer: None,
1957        });
1958        cx.emit(Event::ExcerptsAdded {
1959            buffer,
1960            predecessor: prev_excerpt_id,
1961            excerpts,
1962        });
1963        cx.notify();
1964    }
1965
1966    pub fn clear(&mut self, cx: &mut Context<Self>) {
1967        self.sync(cx);
1968        let ids = self.excerpt_ids();
1969        self.buffers.borrow_mut().clear();
1970        let mut snapshot = self.snapshot.borrow_mut();
1971        let start = ExcerptOffset::new(0);
1972        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1973        snapshot.excerpts = Default::default();
1974        snapshot.trailing_excerpt_update_count += 1;
1975        snapshot.is_dirty = false;
1976        snapshot.has_deleted_file = false;
1977        snapshot.has_conflict = false;
1978
1979        self.sync_diff_transforms(
1980            &mut snapshot,
1981            vec![Edit {
1982                old: start..prev_len,
1983                new: start..start,
1984            }],
1985            DiffChangeKind::BufferEdited,
1986        );
1987        cx.emit(Event::Edited {
1988            singleton_buffer_edited: false,
1989            edited_buffer: None,
1990        });
1991        cx.emit(Event::ExcerptsRemoved { ids });
1992        cx.notify();
1993    }
1994
1995    pub fn excerpts_for_buffer(
1996        &self,
1997        buffer_id: BufferId,
1998        cx: &App,
1999    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2000        let mut excerpts = Vec::new();
2001        let snapshot = self.read(cx);
2002        let buffers = self.buffers.borrow();
2003        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2004        for locator in buffers
2005            .get(&buffer_id)
2006            .map(|state| &state.excerpts)
2007            .into_iter()
2008            .flatten()
2009        {
2010            cursor.seek_forward(&Some(locator), Bias::Left, &());
2011            if let Some(excerpt) = cursor.item() {
2012                if excerpt.locator == *locator {
2013                    excerpts.push((excerpt.id, excerpt.range.clone()));
2014                }
2015            }
2016        }
2017
2018        excerpts
2019    }
2020
2021    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2022        let snapshot = self.read(cx);
2023        let buffers = self.buffers.borrow();
2024        let mut excerpts = snapshot
2025            .excerpts
2026            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
2027        let mut diff_transforms = snapshot
2028            .diff_transforms
2029            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
2030        diff_transforms.next(&());
2031        let locators = buffers
2032            .get(&buffer_id)
2033            .into_iter()
2034            .flat_map(|state| &state.excerpts);
2035        let mut result = Vec::new();
2036        for locator in locators {
2037            excerpts.seek_forward(&Some(locator), Bias::Left, &());
2038            if let Some(excerpt) = excerpts.item() {
2039                if excerpt.locator == *locator {
2040                    let excerpt_start = excerpts.start().1.clone();
2041                    let excerpt_end =
2042                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2043
2044                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
2045                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
2046                    let start = diff_transforms.start().1 .0 + overshoot;
2047
2048                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
2049                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
2050                    let end = diff_transforms.start().1 .0 + overshoot;
2051
2052                    result.push(start..end)
2053                }
2054            }
2055        }
2056        result
2057    }
2058
2059    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2060        self.snapshot
2061            .borrow()
2062            .excerpts
2063            .iter()
2064            .map(|entry| entry.buffer_id)
2065            .collect()
2066    }
2067
2068    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2069        self.snapshot
2070            .borrow()
2071            .excerpts
2072            .iter()
2073            .map(|entry| entry.id)
2074            .collect()
2075    }
2076
2077    pub fn excerpt_containing(
2078        &self,
2079        position: impl ToOffset,
2080        cx: &App,
2081    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2082        let snapshot = self.read(cx);
2083        let offset = position.to_offset(&snapshot);
2084
2085        let mut cursor = snapshot.cursor::<usize>();
2086        cursor.seek(&offset);
2087        cursor
2088            .excerpt()
2089            .or_else(|| snapshot.excerpts.last())
2090            .map(|excerpt| {
2091                (
2092                    excerpt.id,
2093                    self.buffers
2094                        .borrow()
2095                        .get(&excerpt.buffer_id)
2096                        .unwrap()
2097                        .buffer
2098                        .clone(),
2099                    excerpt.range.context.clone(),
2100                )
2101            })
2102    }
2103
2104    // If point is at the end of the buffer, the last excerpt is returned
2105    pub fn point_to_buffer_offset<T: ToOffset>(
2106        &self,
2107        point: T,
2108        cx: &App,
2109    ) -> Option<(Entity<Buffer>, usize)> {
2110        let snapshot = self.read(cx);
2111        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2112        Some((
2113            self.buffers
2114                .borrow()
2115                .get(&buffer.remote_id())?
2116                .buffer
2117                .clone(),
2118            offset,
2119        ))
2120    }
2121
2122    // If point is at the end of the buffer, the last excerpt is returned
2123    pub fn point_to_buffer_point<T: ToPoint>(
2124        &self,
2125        point: T,
2126        cx: &App,
2127    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2128        let snapshot = self.read(cx);
2129        let (buffer, point, is_main_buffer) =
2130            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2131        Some((
2132            self.buffers
2133                .borrow()
2134                .get(&buffer.remote_id())?
2135                .buffer
2136                .clone(),
2137            point,
2138            is_main_buffer,
2139        ))
2140    }
2141
2142    pub fn buffer_point_to_anchor(
2143        &self,
2144        buffer: &Entity<Buffer>,
2145        point: Point,
2146        cx: &App,
2147    ) -> Option<Anchor> {
2148        let mut found = None;
2149        let snapshot = buffer.read(cx).snapshot();
2150        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2151            let start = range.context.start.to_point(&snapshot);
2152            let end = range.context.end.to_point(&snapshot);
2153            if start <= point && point < end {
2154                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2155                break;
2156            }
2157            if point < start {
2158                found = Some((start, excerpt_id));
2159            }
2160            if point > end {
2161                found = Some((end, excerpt_id));
2162            }
2163        }
2164
2165        found.map(|(point, excerpt_id)| {
2166            let text_anchor = snapshot.anchor_after(point);
2167            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2168        })
2169    }
2170
2171    pub fn remove_excerpts(
2172        &mut self,
2173        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2174        cx: &mut Context<Self>,
2175    ) {
2176        self.sync(cx);
2177        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2178        if ids.is_empty() {
2179            return;
2180        }
2181
2182        let mut buffers = self.buffers.borrow_mut();
2183        let mut snapshot = self.snapshot.borrow_mut();
2184        let mut new_excerpts = SumTree::default();
2185        let mut cursor = snapshot
2186            .excerpts
2187            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2188        let mut edits = Vec::new();
2189        let mut excerpt_ids = ids.iter().copied().peekable();
2190        let mut removed_buffer_ids = Vec::new();
2191
2192        while let Some(excerpt_id) = excerpt_ids.next() {
2193            self.paths_by_excerpt.remove(&excerpt_id);
2194            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2195            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2196            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2197
2198            if let Some(mut excerpt) = cursor.item() {
2199                if excerpt.id != excerpt_id {
2200                    continue;
2201                }
2202                let mut old_start = cursor.start().1;
2203
2204                // Skip over the removed excerpt.
2205                'remove_excerpts: loop {
2206                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2207                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2208                        if buffer_state.excerpts.is_empty() {
2209                            log::debug!(
2210                                "removing buffer and diff for buffer {}",
2211                                excerpt.buffer_id
2212                            );
2213                            buffers.remove(&excerpt.buffer_id);
2214                            removed_buffer_ids.push(excerpt.buffer_id);
2215                        }
2216                    }
2217                    cursor.next(&());
2218
2219                    // Skip over any subsequent excerpts that are also removed.
2220                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2221                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2222                        if let Some(next_excerpt) = cursor.item() {
2223                            if next_excerpt.locator == *next_locator {
2224                                excerpt_ids.next();
2225                                excerpt = next_excerpt;
2226                                continue 'remove_excerpts;
2227                            }
2228                        }
2229                    }
2230
2231                    break;
2232                }
2233
2234                // When removing the last excerpt, remove the trailing newline from
2235                // the previous excerpt.
2236                if cursor.item().is_none() && old_start.value > 0 {
2237                    old_start.value -= 1;
2238                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2239                }
2240
2241                // Push an edit for the removal of this run of excerpts.
2242                let old_end = cursor.start().1;
2243                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2244                edits.push(Edit {
2245                    old: old_start..old_end,
2246                    new: new_start..new_start,
2247                });
2248            }
2249        }
2250        let suffix = cursor.suffix(&());
2251        let changed_trailing_excerpt = suffix.is_empty();
2252        new_excerpts.append(suffix, &());
2253        drop(cursor);
2254        snapshot.excerpts = new_excerpts;
2255        for buffer_id in removed_buffer_ids {
2256            self.diffs.remove(&buffer_id);
2257            snapshot.diffs.remove(&buffer_id);
2258        }
2259
2260        if changed_trailing_excerpt {
2261            snapshot.trailing_excerpt_update_count += 1;
2262        }
2263
2264        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2265        self.buffer_changed_since_sync.replace(true);
2266        cx.emit(Event::Edited {
2267            singleton_buffer_edited: false,
2268            edited_buffer: None,
2269        });
2270        cx.emit(Event::ExcerptsRemoved { ids });
2271        cx.notify();
2272    }
2273
2274    pub fn wait_for_anchors<'a>(
2275        &self,
2276        anchors: impl 'a + Iterator<Item = Anchor>,
2277        cx: &mut Context<Self>,
2278    ) -> impl 'static + Future<Output = Result<()>> {
2279        let borrow = self.buffers.borrow();
2280        let mut error = None;
2281        let mut futures = Vec::new();
2282        for anchor in anchors {
2283            if let Some(buffer_id) = anchor.buffer_id {
2284                if let Some(buffer) = borrow.get(&buffer_id) {
2285                    buffer.buffer.update(cx, |buffer, _| {
2286                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2287                    });
2288                } else {
2289                    error = Some(anyhow!(
2290                        "buffer {buffer_id} is not part of this multi-buffer"
2291                    ));
2292                    break;
2293                }
2294            }
2295        }
2296        async move {
2297            if let Some(error) = error {
2298                Err(error)?;
2299            }
2300            for future in futures {
2301                future.await?;
2302            }
2303            Ok(())
2304        }
2305    }
2306
2307    pub fn text_anchor_for_position<T: ToOffset>(
2308        &self,
2309        position: T,
2310        cx: &App,
2311    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2312        let snapshot = self.read(cx);
2313        let anchor = snapshot.anchor_before(position);
2314        let buffer = self
2315            .buffers
2316            .borrow()
2317            .get(&anchor.buffer_id?)?
2318            .buffer
2319            .clone();
2320        Some((buffer, anchor.text_anchor))
2321    }
2322
2323    fn on_buffer_event(
2324        &mut self,
2325        buffer: Entity<Buffer>,
2326        event: &language::BufferEvent,
2327        cx: &mut Context<Self>,
2328    ) {
2329        cx.emit(match event {
2330            language::BufferEvent::Edited => Event::Edited {
2331                singleton_buffer_edited: true,
2332                edited_buffer: Some(buffer.clone()),
2333            },
2334            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2335            language::BufferEvent::Saved => Event::Saved,
2336            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2337            language::BufferEvent::Reloaded => Event::Reloaded,
2338            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2339            language::BufferEvent::LanguageChanged => {
2340                Event::LanguageChanged(buffer.read(cx).remote_id())
2341            }
2342            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2343            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2344            language::BufferEvent::Closed => Event::Closed,
2345            language::BufferEvent::Discarded => Event::Discarded,
2346            language::BufferEvent::CapabilityChanged => {
2347                self.capability = buffer.read(cx).capability();
2348                Event::CapabilityChanged
2349            }
2350            language::BufferEvent::Operation { .. } => return,
2351        });
2352    }
2353
2354    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2355        self.sync(cx);
2356        let mut snapshot = self.snapshot.borrow_mut();
2357        let diff = diff.read(cx);
2358        let buffer_id = diff.buffer_id;
2359        let diff = diff.snapshot(cx);
2360        snapshot.diffs.insert(buffer_id, diff);
2361    }
2362
2363    fn buffer_diff_changed(
2364        &mut self,
2365        diff: Entity<BufferDiff>,
2366        range: Range<text::Anchor>,
2367        cx: &mut Context<Self>,
2368    ) {
2369        self.sync(cx);
2370        self.buffer_changed_since_sync.replace(true);
2371
2372        let diff = diff.read(cx);
2373        let buffer_id = diff.buffer_id;
2374        let buffers = self.buffers.borrow();
2375        let Some(buffer_state) = buffers.get(&buffer_id) else {
2376            return;
2377        };
2378
2379        let buffer = buffer_state.buffer.read(cx);
2380        let diff_change_range = range.to_offset(buffer);
2381
2382        let new_diff = diff.snapshot(cx);
2383        let mut snapshot = self.snapshot.borrow_mut();
2384        let base_text_changed = snapshot
2385            .diffs
2386            .get(&buffer_id)
2387            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2388
2389        snapshot.diffs.insert(buffer_id, new_diff);
2390
2391        let mut excerpt_edits = Vec::new();
2392        for locator in &buffer_state.excerpts {
2393            let mut cursor = snapshot
2394                .excerpts
2395                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2396            cursor.seek_forward(&Some(locator), Bias::Left, &());
2397            if let Some(excerpt) = cursor.item() {
2398                if excerpt.locator == *locator {
2399                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2400                    if diff_change_range.end < excerpt_buffer_range.start
2401                        || diff_change_range.start > excerpt_buffer_range.end
2402                    {
2403                        continue;
2404                    }
2405                    let excerpt_start = cursor.start().1;
2406                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2407                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2408                        diff_change_range
2409                            .start
2410                            .saturating_sub(excerpt_buffer_range.start),
2411                    );
2412                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2413                        diff_change_range
2414                            .end
2415                            .saturating_sub(excerpt_buffer_range.start),
2416                    );
2417                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2418                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2419                    excerpt_edits.push(Edit {
2420                        old: edit_start..edit_end,
2421                        new: edit_start..edit_end,
2422                    });
2423                }
2424            }
2425        }
2426
2427        self.sync_diff_transforms(
2428            &mut snapshot,
2429            excerpt_edits,
2430            DiffChangeKind::DiffUpdated {
2431                base_changed: base_text_changed,
2432            },
2433        );
2434        cx.emit(Event::Edited {
2435            singleton_buffer_edited: false,
2436            edited_buffer: None,
2437        });
2438    }
2439
2440    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2441        self.buffers
2442            .borrow()
2443            .values()
2444            .map(|state| state.buffer.clone())
2445            .collect()
2446    }
2447
2448    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2449        self.buffers
2450            .borrow()
2451            .get(&buffer_id)
2452            .map(|state| state.buffer.clone())
2453    }
2454
2455    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2456        self.point_to_buffer_offset(point, cx)
2457            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2458    }
2459
2460    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2461        let buffer_id = self
2462            .snapshot
2463            .borrow()
2464            .excerpts
2465            .first()
2466            .map(|excerpt| excerpt.buffer.remote_id());
2467        buffer_id
2468            .and_then(|buffer_id| self.buffer(buffer_id))
2469            .map(|buffer| {
2470                let buffer = buffer.read(cx);
2471                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2472            })
2473            .unwrap_or_else(move || self.language_settings_at(0, cx))
2474    }
2475
2476    pub fn language_settings_at<'a, T: ToOffset>(
2477        &'a self,
2478        point: T,
2479        cx: &'a App,
2480    ) -> Cow<'a, LanguageSettings> {
2481        let mut language = None;
2482        let mut file = None;
2483        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2484            let buffer = buffer.read(cx);
2485            language = buffer.language_at(offset);
2486            file = buffer.file();
2487        }
2488        language_settings(language.map(|l| l.name()), file, cx)
2489    }
2490
2491    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2492        self.buffers
2493            .borrow()
2494            .values()
2495            .for_each(|state| f(&state.buffer))
2496    }
2497
2498    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2499        if let Some(title) = self.title.as_ref() {
2500            return title.into();
2501        }
2502
2503        if let Some(buffer) = self.as_singleton() {
2504            if let Some(file) = buffer.read(cx).file() {
2505                return file.file_name(cx).to_string_lossy();
2506            }
2507        }
2508
2509        "untitled".into()
2510    }
2511
2512    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2513        self.title = Some(title);
2514        cx.notify();
2515    }
2516
2517    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2518    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2519        for buffer_state in self.buffers.borrow().values() {
2520            buffer_state
2521                .buffer
2522                .update(cx, |buffer, _cx| buffer.refresh_preview());
2523        }
2524    }
2525
2526    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2527    pub fn preserve_preview(&self, cx: &App) -> bool {
2528        self.buffers
2529            .borrow()
2530            .values()
2531            .all(|state| state.buffer.read(cx).preserve_preview())
2532    }
2533
2534    #[cfg(any(test, feature = "test-support"))]
2535    pub fn is_parsing(&self, cx: &App) -> bool {
2536        self.as_singleton().unwrap().read(cx).is_parsing()
2537    }
2538
2539    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2540        let buffer_id = diff.read(cx).buffer_id;
2541        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2542        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2543    }
2544
2545    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2546        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2547    }
2548
2549    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2550        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2551    }
2552
2553    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2554        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2555    }
2556
2557    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2558        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2559        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2560    }
2561
2562    pub fn all_diff_hunks_expanded(&self) -> bool {
2563        self.snapshot.borrow().all_diff_hunks_expanded
2564    }
2565
2566    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2567        self.read(cx)
2568            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2569            .nth(1)
2570            .is_some()
2571    }
2572
2573    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2574        let snapshot = self.read(cx);
2575        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2576        let offset_range = range.to_offset(&snapshot);
2577        cursor.seek(&offset_range.start, Bias::Left, &());
2578        while let Some(item) = cursor.item() {
2579            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2580                break;
2581            }
2582            if item.hunk_info().is_some() {
2583                return true;
2584            }
2585            cursor.next(&());
2586        }
2587        false
2588    }
2589
2590    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2591        let snapshot = self.read(cx);
2592        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2593        for range in ranges {
2594            let range = range.to_point(&snapshot);
2595            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2596            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2597            let start = start.saturating_sub(1);
2598            let end = snapshot.len().min(end + 1);
2599            cursor.seek(&start, Bias::Right, &());
2600            while let Some(item) = cursor.item() {
2601                if *cursor.start() >= end {
2602                    break;
2603                }
2604                if item.hunk_info().is_some() {
2605                    return true;
2606                }
2607                cursor.next(&());
2608            }
2609        }
2610        false
2611    }
2612
2613    pub fn expand_or_collapse_diff_hunks_inner(
2614        &mut self,
2615        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2616        expand: bool,
2617        cx: &mut Context<Self>,
2618    ) {
2619        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2620            return;
2621        }
2622        self.sync(cx);
2623        let mut snapshot = self.snapshot.borrow_mut();
2624        let mut excerpt_edits = Vec::new();
2625        let mut last_hunk_row = None;
2626        for (range, end_excerpt_id) in ranges {
2627            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2628                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2629                    continue;
2630                }
2631                if last_hunk_row.map_or(false, |row| row >= diff_hunk.row_range.start) {
2632                    continue;
2633                }
2634                let start = Anchor::in_buffer(
2635                    diff_hunk.excerpt_id,
2636                    diff_hunk.buffer_id,
2637                    diff_hunk.buffer_range.start,
2638                );
2639                let end = Anchor::in_buffer(
2640                    diff_hunk.excerpt_id,
2641                    diff_hunk.buffer_id,
2642                    diff_hunk.buffer_range.end,
2643                );
2644                let start = snapshot.excerpt_offset_for_anchor(&start);
2645                let end = snapshot.excerpt_offset_for_anchor(&end);
2646                last_hunk_row = Some(diff_hunk.row_range.start);
2647                excerpt_edits.push(text::Edit {
2648                    old: start..end,
2649                    new: start..end,
2650                });
2651            }
2652        }
2653
2654        self.sync_diff_transforms(
2655            &mut snapshot,
2656            excerpt_edits,
2657            DiffChangeKind::ExpandOrCollapseHunks { expand },
2658        );
2659        cx.emit(Event::DiffHunksToggled);
2660        cx.emit(Event::Edited {
2661            singleton_buffer_edited: false,
2662            edited_buffer: None,
2663        });
2664    }
2665
2666    pub fn expand_or_collapse_diff_hunks(
2667        &mut self,
2668        ranges: Vec<Range<Anchor>>,
2669        expand: bool,
2670        cx: &mut Context<Self>,
2671    ) {
2672        let snapshot = self.snapshot.borrow().clone();
2673        let ranges = ranges.iter().map(move |range| {
2674            let end_excerpt_id = range.end.excerpt_id;
2675            let range = range.to_point(&snapshot);
2676            let mut peek_end = range.end;
2677            if range.end.row < snapshot.max_row().0 {
2678                peek_end = Point::new(range.end.row + 1, 0);
2679            };
2680            (range.start..peek_end, end_excerpt_id)
2681        });
2682        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2683    }
2684
2685    pub fn resize_excerpt(
2686        &mut self,
2687        id: ExcerptId,
2688        range: Range<text::Anchor>,
2689        cx: &mut Context<Self>,
2690    ) {
2691        self.sync(cx);
2692
2693        let mut snapshot = self.snapshot.borrow_mut();
2694        let locator = snapshot.excerpt_locator_for_id(id);
2695        let mut new_excerpts = SumTree::default();
2696        let mut cursor = snapshot
2697            .excerpts
2698            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2699        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2700
2701        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2702        new_excerpts.append(prefix, &());
2703
2704        let mut excerpt = cursor.item().unwrap().clone();
2705        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2706
2707        excerpt.range.context.start = range.start;
2708        excerpt.range.context.end = range.end;
2709        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2710
2711        excerpt.text_summary = excerpt
2712            .buffer
2713            .text_summary_for_range(excerpt.range.context.clone());
2714
2715        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2716        let old_start_offset = cursor.start().1;
2717        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2718        let edit = Edit {
2719            old: old_start_offset..old_start_offset + old_text_len,
2720            new: new_start_offset..new_start_offset + new_text_len,
2721        };
2722
2723        if let Some(last_edit) = edits.last_mut() {
2724            if last_edit.old.end == edit.old.start {
2725                last_edit.old.end = edit.old.end;
2726                last_edit.new.end = edit.new.end;
2727            } else {
2728                edits.push(edit);
2729            }
2730        } else {
2731            edits.push(edit);
2732        }
2733
2734        new_excerpts.push(excerpt, &());
2735
2736        cursor.next(&());
2737
2738        new_excerpts.append(cursor.suffix(&()), &());
2739
2740        drop(cursor);
2741        snapshot.excerpts = new_excerpts;
2742
2743        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2744        cx.emit(Event::Edited {
2745            singleton_buffer_edited: false,
2746            edited_buffer: None,
2747        });
2748        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2749        cx.notify();
2750    }
2751
2752    pub fn expand_excerpts(
2753        &mut self,
2754        ids: impl IntoIterator<Item = ExcerptId>,
2755        line_count: u32,
2756        direction: ExpandExcerptDirection,
2757        cx: &mut Context<Self>,
2758    ) {
2759        if line_count == 0 {
2760            return;
2761        }
2762        self.sync(cx);
2763        if !self.excerpts_by_path.is_empty() {
2764            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2765            return;
2766        }
2767        let mut snapshot = self.snapshot.borrow_mut();
2768
2769        let ids = ids.into_iter().collect::<Vec<_>>();
2770        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2771        let mut new_excerpts = SumTree::default();
2772        let mut cursor = snapshot
2773            .excerpts
2774            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2775        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2776
2777        for locator in &locators {
2778            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2779            new_excerpts.append(prefix, &());
2780
2781            let mut excerpt = cursor.item().unwrap().clone();
2782            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2783
2784            let up_line_count = if direction.should_expand_up() {
2785                line_count
2786            } else {
2787                0
2788            };
2789
2790            let start_row = excerpt
2791                .range
2792                .context
2793                .start
2794                .to_point(&excerpt.buffer)
2795                .row
2796                .saturating_sub(up_line_count);
2797            let start_point = Point::new(start_row, 0);
2798            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2799
2800            let down_line_count = if direction.should_expand_down() {
2801                line_count
2802            } else {
2803                0
2804            };
2805
2806            let mut end_point = excerpt.buffer.clip_point(
2807                excerpt.range.context.end.to_point(&excerpt.buffer)
2808                    + Point::new(down_line_count, 0),
2809                Bias::Left,
2810            );
2811            end_point.column = excerpt.buffer.line_len(end_point.row);
2812            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2813            excerpt.max_buffer_row = end_point.row;
2814
2815            excerpt.text_summary = excerpt
2816                .buffer
2817                .text_summary_for_range(excerpt.range.context.clone());
2818
2819            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2820            let old_start_offset = cursor.start().1;
2821            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2822            let edit = Edit {
2823                old: old_start_offset..old_start_offset + old_text_len,
2824                new: new_start_offset..new_start_offset + new_text_len,
2825            };
2826
2827            if let Some(last_edit) = edits.last_mut() {
2828                if last_edit.old.end == edit.old.start {
2829                    last_edit.old.end = edit.old.end;
2830                    last_edit.new.end = edit.new.end;
2831                } else {
2832                    edits.push(edit);
2833                }
2834            } else {
2835                edits.push(edit);
2836            }
2837
2838            new_excerpts.push(excerpt, &());
2839
2840            cursor.next(&());
2841        }
2842
2843        new_excerpts.append(cursor.suffix(&()), &());
2844
2845        drop(cursor);
2846        snapshot.excerpts = new_excerpts;
2847
2848        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2849        cx.emit(Event::Edited {
2850            singleton_buffer_edited: false,
2851            edited_buffer: None,
2852        });
2853        cx.emit(Event::ExcerptsExpanded { ids });
2854        cx.notify();
2855    }
2856
2857    fn sync(&self, cx: &App) {
2858        let changed = self.buffer_changed_since_sync.replace(false);
2859        if !changed {
2860            return;
2861        }
2862
2863        let mut snapshot = self.snapshot.borrow_mut();
2864        let mut excerpts_to_edit = Vec::new();
2865        let mut non_text_state_updated = false;
2866        let mut is_dirty = false;
2867        let mut has_deleted_file = false;
2868        let mut has_conflict = false;
2869        let mut edited = false;
2870        let mut buffers = self.buffers.borrow_mut();
2871        for buffer_state in buffers.values_mut() {
2872            let buffer = buffer_state.buffer.read(cx);
2873            let version = buffer.version();
2874            let non_text_state_update_count = buffer.non_text_state_update_count();
2875
2876            let buffer_edited = version.changed_since(&buffer_state.last_version);
2877            let buffer_non_text_state_updated =
2878                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2879            if buffer_edited || buffer_non_text_state_updated {
2880                buffer_state.last_version = version;
2881                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2882                excerpts_to_edit.extend(
2883                    buffer_state
2884                        .excerpts
2885                        .iter()
2886                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2887                );
2888            }
2889
2890            edited |= buffer_edited;
2891            non_text_state_updated |= buffer_non_text_state_updated;
2892            is_dirty |= buffer.is_dirty();
2893            has_deleted_file |= buffer
2894                .file()
2895                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2896            has_conflict |= buffer.has_conflict();
2897        }
2898        if edited {
2899            snapshot.edit_count += 1;
2900        }
2901        if non_text_state_updated {
2902            snapshot.non_text_state_update_count += 1;
2903        }
2904        snapshot.is_dirty = is_dirty;
2905        snapshot.has_deleted_file = has_deleted_file;
2906        snapshot.has_conflict = has_conflict;
2907
2908        for (id, diff) in self.diffs.iter() {
2909            if snapshot.diffs.get(&id).is_none() {
2910                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2911            }
2912        }
2913
2914        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2915
2916        let mut edits = Vec::new();
2917        let mut new_excerpts = SumTree::default();
2918        let mut cursor = snapshot
2919            .excerpts
2920            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2921
2922        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2923            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2924            let old_excerpt = cursor.item().unwrap();
2925            let buffer = buffer.read(cx);
2926            let buffer_id = buffer.remote_id();
2927
2928            let mut new_excerpt;
2929            if buffer_edited {
2930                edits.extend(
2931                    buffer
2932                        .edits_since_in_range::<usize>(
2933                            old_excerpt.buffer.version(),
2934                            old_excerpt.range.context.clone(),
2935                        )
2936                        .map(|edit| {
2937                            let excerpt_old_start = cursor.start().1;
2938                            let excerpt_new_start =
2939                                ExcerptOffset::new(new_excerpts.summary().text.len);
2940                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2941                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2942                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2943                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2944                            Edit {
2945                                old: old_start..old_end,
2946                                new: new_start..new_end,
2947                            }
2948                        }),
2949                );
2950
2951                new_excerpt = Excerpt::new(
2952                    old_excerpt.id,
2953                    locator.clone(),
2954                    buffer_id,
2955                    buffer.snapshot(),
2956                    old_excerpt.range.clone(),
2957                    old_excerpt.has_trailing_newline,
2958                );
2959            } else {
2960                new_excerpt = old_excerpt.clone();
2961                new_excerpt.buffer = buffer.snapshot();
2962            }
2963
2964            new_excerpts.push(new_excerpt, &());
2965            cursor.next(&());
2966        }
2967        new_excerpts.append(cursor.suffix(&()), &());
2968
2969        drop(cursor);
2970        snapshot.excerpts = new_excerpts;
2971
2972        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2973    }
2974
2975    fn sync_diff_transforms(
2976        &self,
2977        snapshot: &mut MultiBufferSnapshot,
2978        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2979        change_kind: DiffChangeKind,
2980    ) {
2981        if excerpt_edits.is_empty() {
2982            return;
2983        }
2984
2985        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2986        let mut old_diff_transforms = snapshot
2987            .diff_transforms
2988            .cursor::<(ExcerptOffset, usize)>(&());
2989        let mut new_diff_transforms = SumTree::default();
2990        let mut old_expanded_hunks = HashSet::default();
2991        let mut output_edits = Vec::new();
2992        let mut output_delta = 0_isize;
2993        let mut at_transform_boundary = true;
2994        let mut end_of_current_insert = None;
2995
2996        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2997        while let Some(edit) = excerpt_edits.next() {
2998            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2999            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3000                excerpts.prev(&());
3001            }
3002
3003            // Keep any transforms that are before the edit.
3004            if at_transform_boundary {
3005                at_transform_boundary = false;
3006                let transforms_before_edit =
3007                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3008                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3009                if let Some(transform) = old_diff_transforms.item() {
3010                    if old_diff_transforms.end(&()).0 == edit.old.start
3011                        && old_diff_transforms.start().0 < edit.old.start
3012                    {
3013                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3014                        old_diff_transforms.next(&());
3015                    }
3016                }
3017            }
3018
3019            // Compute the start of the edit in output coordinates.
3020            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3021            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3022            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3023
3024            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3025                &edit,
3026                &mut excerpts,
3027                &mut old_diff_transforms,
3028                &mut new_diff_transforms,
3029                &mut end_of_current_insert,
3030                &mut old_expanded_hunks,
3031                &snapshot,
3032                change_kind,
3033            );
3034
3035            // Compute the end of the edit in output coordinates.
3036            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3037            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3038            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3039            let edit_new_end =
3040                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3041            let output_edit = Edit {
3042                old: edit_old_start..edit_old_end,
3043                new: edit_new_start..edit_new_end,
3044            };
3045
3046            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3047            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3048            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3049                output_edits.push(output_edit);
3050            }
3051
3052            // If this is the last edit that intersects the current diff transform,
3053            // then recreate the content up to the end of this transform, to prepare
3054            // for reusing additional slices of the old transforms.
3055            if excerpt_edits.peek().map_or(true, |next_edit| {
3056                next_edit.old.start >= old_diff_transforms.end(&()).0
3057            }) {
3058                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3059                    && match old_diff_transforms.item() {
3060                        Some(DiffTransform::BufferContent {
3061                            inserted_hunk_info: Some(hunk),
3062                            ..
3063                        }) => excerpts.item().is_some_and(|excerpt| {
3064                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3065                        }),
3066                        _ => true,
3067                    };
3068
3069                let mut excerpt_offset = edit.new.end;
3070                if !keep_next_old_transform {
3071                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3072                    old_diff_transforms.next(&());
3073                }
3074
3075                old_expanded_hunks.clear();
3076                self.push_buffer_content_transform(
3077                    &snapshot,
3078                    &mut new_diff_transforms,
3079                    excerpt_offset,
3080                    end_of_current_insert,
3081                );
3082                at_transform_boundary = true;
3083            }
3084        }
3085
3086        // Keep any transforms that are after the last edit.
3087        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3088
3089        // Ensure there's always at least one buffer content transform.
3090        if new_diff_transforms.is_empty() {
3091            new_diff_transforms.push(
3092                DiffTransform::BufferContent {
3093                    summary: Default::default(),
3094                    inserted_hunk_info: None,
3095                },
3096                &(),
3097            );
3098        }
3099
3100        self.subscriptions.publish(output_edits);
3101        drop(old_diff_transforms);
3102        drop(excerpts);
3103        snapshot.diff_transforms = new_diff_transforms;
3104        snapshot.edit_count += 1;
3105
3106        #[cfg(any(test, feature = "test-support"))]
3107        snapshot.check_invariants();
3108    }
3109
3110    fn recompute_diff_transforms_for_edit(
3111        &self,
3112        edit: &Edit<TypedOffset<Excerpt>>,
3113        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3114        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3115        new_diff_transforms: &mut SumTree<DiffTransform>,
3116        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3117        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3118        snapshot: &MultiBufferSnapshot,
3119        change_kind: DiffChangeKind,
3120    ) -> bool {
3121        log::trace!(
3122            "recomputing diff transform for edit {:?} => {:?}",
3123            edit.old.start.value..edit.old.end.value,
3124            edit.new.start.value..edit.new.end.value
3125        );
3126
3127        // Record which hunks were previously expanded.
3128        while let Some(item) = old_diff_transforms.item() {
3129            if let Some(hunk_info) = item.hunk_info() {
3130                log::trace!(
3131                    "previously expanded hunk at {}",
3132                    old_diff_transforms.start().0
3133                );
3134                old_expanded_hunks.insert(hunk_info);
3135            }
3136            if old_diff_transforms.end(&()).0 > edit.old.end {
3137                break;
3138            }
3139            old_diff_transforms.next(&());
3140        }
3141
3142        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3143        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3144        if old_expanded_hunks.is_empty()
3145            && change_kind == DiffChangeKind::BufferEdited
3146            && !all_diff_hunks_expanded
3147        {
3148            return false;
3149        }
3150
3151        // Visit each excerpt that intersects the edit.
3152        let mut did_expand_hunks = false;
3153        while let Some(excerpt) = excerpts.item() {
3154            // Recompute the expanded hunks in the portion of the excerpt that
3155            // intersects the edit.
3156            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3157                let buffer = &excerpt.buffer;
3158                let excerpt_start = *excerpts.start();
3159                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3160                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3161                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3162                let edit_buffer_start =
3163                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3164                let edit_buffer_end =
3165                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3166                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3167                let edit_anchor_range =
3168                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3169
3170                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3171                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3172                        continue;
3173                    }
3174
3175                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3176                    if hunk_buffer_range.start < excerpt_buffer_start {
3177                        log::trace!("skipping hunk that starts before excerpt");
3178                        continue;
3179                    }
3180
3181                    let hunk_info = DiffTransformHunkInfo {
3182                        excerpt_id: excerpt.id,
3183                        hunk_start_anchor: hunk.buffer_range.start,
3184                        hunk_secondary_status: hunk.secondary_status,
3185                    };
3186
3187                    let hunk_excerpt_start = excerpt_start
3188                        + ExcerptOffset::new(
3189                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3190                        );
3191                    let hunk_excerpt_end = excerpt_end.min(
3192                        excerpt_start
3193                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3194                    );
3195
3196                    self.push_buffer_content_transform(
3197                        snapshot,
3198                        new_diff_transforms,
3199                        hunk_excerpt_start,
3200                        *end_of_current_insert,
3201                    );
3202
3203                    // For every existing hunk, determine if it was previously expanded
3204                    // and if it should currently be expanded.
3205                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3206                    let should_expand_hunk = match &change_kind {
3207                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3208                            was_previously_expanded || all_diff_hunks_expanded
3209                        }
3210                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3211                            let intersects = hunk_buffer_range.is_empty()
3212                                || hunk_buffer_range.end > edit_buffer_start;
3213                            if *expand {
3214                                intersects || was_previously_expanded || all_diff_hunks_expanded
3215                            } else {
3216                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3217                            }
3218                        }
3219                        _ => was_previously_expanded || all_diff_hunks_expanded,
3220                    };
3221
3222                    if should_expand_hunk {
3223                        did_expand_hunks = true;
3224                        log::trace!(
3225                            "expanding hunk {:?}, excerpt:{:?}",
3226                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3227                            excerpt.id
3228                        );
3229
3230                        if !hunk.diff_base_byte_range.is_empty()
3231                            && hunk_buffer_range.start >= edit_buffer_start
3232                            && hunk_buffer_range.start <= excerpt_buffer_end
3233                        {
3234                            let base_text = diff.base_text();
3235                            let mut text_cursor =
3236                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3237                            let mut base_text_summary =
3238                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3239
3240                            let mut has_trailing_newline = false;
3241                            if base_text_summary.last_line_chars > 0 {
3242                                base_text_summary += TextSummary::newline();
3243                                has_trailing_newline = true;
3244                            }
3245
3246                            new_diff_transforms.push(
3247                                DiffTransform::DeletedHunk {
3248                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3249                                    summary: base_text_summary,
3250                                    buffer_id: excerpt.buffer_id,
3251                                    hunk_info,
3252                                    has_trailing_newline,
3253                                },
3254                                &(),
3255                            );
3256                        }
3257
3258                        if !hunk_buffer_range.is_empty() {
3259                            *end_of_current_insert =
3260                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3261                        }
3262                    }
3263                }
3264            }
3265
3266            if excerpts.end(&()) <= edit.new.end {
3267                excerpts.next(&());
3268            } else {
3269                break;
3270            }
3271        }
3272
3273        did_expand_hunks || !old_expanded_hunks.is_empty()
3274    }
3275
3276    fn append_diff_transforms(
3277        &self,
3278        new_transforms: &mut SumTree<DiffTransform>,
3279        subtree: SumTree<DiffTransform>,
3280    ) {
3281        if let Some(DiffTransform::BufferContent {
3282            inserted_hunk_info,
3283            summary,
3284        }) = subtree.first()
3285        {
3286            if self.extend_last_buffer_content_transform(
3287                new_transforms,
3288                *inserted_hunk_info,
3289                *summary,
3290            ) {
3291                let mut cursor = subtree.cursor::<()>(&());
3292                cursor.next(&());
3293                cursor.next(&());
3294                new_transforms.append(cursor.suffix(&()), &());
3295                return;
3296            }
3297        }
3298        new_transforms.append(subtree, &());
3299    }
3300
3301    fn push_diff_transform(
3302        &self,
3303        new_transforms: &mut SumTree<DiffTransform>,
3304        transform: DiffTransform,
3305    ) {
3306        if let DiffTransform::BufferContent {
3307            inserted_hunk_info: inserted_hunk_anchor,
3308            summary,
3309        } = transform
3310        {
3311            if self.extend_last_buffer_content_transform(
3312                new_transforms,
3313                inserted_hunk_anchor,
3314                summary,
3315            ) {
3316                return;
3317            }
3318        }
3319        new_transforms.push(transform, &());
3320    }
3321
3322    fn push_buffer_content_transform(
3323        &self,
3324        old_snapshot: &MultiBufferSnapshot,
3325        new_transforms: &mut SumTree<DiffTransform>,
3326        end_offset: ExcerptOffset,
3327        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3328    ) {
3329        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3330            (end_offset.min(insertion_end_offset), Some(hunk_info))
3331        });
3332        let unchanged_region = [(end_offset, None)];
3333
3334        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3335        {
3336            let start_offset = new_transforms.summary().excerpt_len();
3337            if end_offset <= start_offset {
3338                continue;
3339            }
3340            let summary_to_add = old_snapshot
3341                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3342
3343            if !self.extend_last_buffer_content_transform(
3344                new_transforms,
3345                inserted_hunk_info,
3346                summary_to_add,
3347            ) {
3348                new_transforms.push(
3349                    DiffTransform::BufferContent {
3350                        summary: summary_to_add,
3351                        inserted_hunk_info,
3352                    },
3353                    &(),
3354                )
3355            }
3356        }
3357    }
3358
3359    fn extend_last_buffer_content_transform(
3360        &self,
3361        new_transforms: &mut SumTree<DiffTransform>,
3362        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3363        summary_to_add: TextSummary,
3364    ) -> bool {
3365        let mut did_extend = false;
3366        new_transforms.update_last(
3367            |last_transform| {
3368                if let DiffTransform::BufferContent {
3369                    summary,
3370                    inserted_hunk_info: inserted_hunk_anchor,
3371                } = last_transform
3372                {
3373                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3374                        *summary += summary_to_add;
3375                        did_extend = true;
3376                    }
3377                }
3378            },
3379            &(),
3380        );
3381        did_extend
3382    }
3383}
3384
3385#[cfg(any(test, feature = "test-support"))]
3386impl MultiBuffer {
3387    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3388        let buffer = cx.new(|cx| Buffer::local(text, cx));
3389        cx.new(|cx| Self::singleton(buffer, cx))
3390    }
3391
3392    pub fn build_multi<const COUNT: usize>(
3393        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3394        cx: &mut gpui::App,
3395    ) -> Entity<Self> {
3396        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3397        for (text, ranges) in excerpts {
3398            let buffer = cx.new(|cx| Buffer::local(text, cx));
3399            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3400                context: range,
3401                primary: None,
3402            });
3403            multi.update(cx, |multi, cx| {
3404                multi.push_excerpts(buffer, excerpt_ranges, cx)
3405            });
3406        }
3407
3408        multi
3409    }
3410
3411    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3412        cx.new(|cx| Self::singleton(buffer, cx))
3413    }
3414
3415    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3416        cx.new(|cx| {
3417            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3418            let mutation_count = rng.gen_range(1..=5);
3419            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3420            multibuffer
3421        })
3422    }
3423
3424    pub fn randomly_edit(
3425        &mut self,
3426        rng: &mut impl rand::Rng,
3427        edit_count: usize,
3428        cx: &mut Context<Self>,
3429    ) {
3430        use util::RandomCharIter;
3431
3432        let snapshot = self.read(cx);
3433        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3434        let mut last_end = None;
3435        for _ in 0..edit_count {
3436            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3437                break;
3438            }
3439
3440            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3441            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3442            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3443            last_end = Some(end);
3444
3445            let mut range = start..end;
3446            if rng.gen_bool(0.2) {
3447                mem::swap(&mut range.start, &mut range.end);
3448            }
3449
3450            let new_text_len = rng.gen_range(0..10);
3451            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3452
3453            edits.push((range, new_text.into()));
3454        }
3455        log::info!("mutating multi-buffer with {:?}", edits);
3456        drop(snapshot);
3457
3458        self.edit(edits, None, cx);
3459    }
3460
3461    pub fn randomly_edit_excerpts(
3462        &mut self,
3463        rng: &mut impl rand::Rng,
3464        mutation_count: usize,
3465        cx: &mut Context<Self>,
3466    ) {
3467        use rand::prelude::*;
3468        use std::env;
3469        use util::RandomCharIter;
3470
3471        let max_excerpts = env::var("MAX_EXCERPTS")
3472            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3473            .unwrap_or(5);
3474
3475        let mut buffers = Vec::new();
3476        for _ in 0..mutation_count {
3477            if rng.gen_bool(0.05) {
3478                log::info!("Clearing multi-buffer");
3479                self.clear(cx);
3480                continue;
3481            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3482                let ids = self.excerpt_ids();
3483                let mut excerpts = HashSet::default();
3484                for _ in 0..rng.gen_range(0..ids.len()) {
3485                    excerpts.extend(ids.choose(rng).copied());
3486                }
3487
3488                let line_count = rng.gen_range(0..5);
3489
3490                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3491
3492                self.expand_excerpts(
3493                    excerpts.iter().cloned(),
3494                    line_count,
3495                    ExpandExcerptDirection::UpAndDown,
3496                    cx,
3497                );
3498                continue;
3499            }
3500
3501            let excerpt_ids = self.excerpt_ids();
3502            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3503                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3504                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3505                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3506                    let buffer = buffers.last().unwrap().read(cx);
3507                    log::info!(
3508                        "Creating new buffer {} with text: {:?}",
3509                        buffer.remote_id(),
3510                        buffer.text()
3511                    );
3512                    buffers.last().unwrap().clone()
3513                } else {
3514                    self.buffers
3515                        .borrow()
3516                        .values()
3517                        .choose(rng)
3518                        .unwrap()
3519                        .buffer
3520                        .clone()
3521                };
3522
3523                let buffer = buffer_handle.read(cx);
3524                let buffer_text = buffer.text();
3525                let ranges = (0..rng.gen_range(0..5))
3526                    .map(|_| {
3527                        let end_ix =
3528                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3529                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3530                        ExcerptRange {
3531                            context: start_ix..end_ix,
3532                            primary: None,
3533                        }
3534                    })
3535                    .collect::<Vec<_>>();
3536                log::info!(
3537                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3538                    buffer_handle.read(cx).remote_id(),
3539                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3540                    ranges
3541                        .iter()
3542                        .map(|r| &buffer_text[r.context.clone()])
3543                        .collect::<Vec<_>>()
3544                );
3545
3546                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3547                log::info!("Inserted with ids: {:?}", excerpt_id);
3548            } else {
3549                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3550                let mut excerpts_to_remove = excerpt_ids
3551                    .choose_multiple(rng, remove_count)
3552                    .cloned()
3553                    .collect::<Vec<_>>();
3554                let snapshot = self.snapshot.borrow();
3555                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3556                drop(snapshot);
3557                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3558                self.remove_excerpts(excerpts_to_remove, cx);
3559            }
3560        }
3561    }
3562
3563    pub fn randomly_mutate(
3564        &mut self,
3565        rng: &mut impl rand::Rng,
3566        mutation_count: usize,
3567        cx: &mut Context<Self>,
3568    ) {
3569        use rand::prelude::*;
3570
3571        if rng.gen_bool(0.7) || self.singleton {
3572            let buffer = self
3573                .buffers
3574                .borrow()
3575                .values()
3576                .choose(rng)
3577                .map(|state| state.buffer.clone());
3578
3579            if let Some(buffer) = buffer {
3580                buffer.update(cx, |buffer, cx| {
3581                    if rng.gen() {
3582                        buffer.randomly_edit(rng, mutation_count, cx);
3583                    } else {
3584                        buffer.randomly_undo_redo(rng, cx);
3585                    }
3586                });
3587            } else {
3588                self.randomly_edit(rng, mutation_count, cx);
3589            }
3590        } else {
3591            self.randomly_edit_excerpts(rng, mutation_count, cx);
3592        }
3593
3594        self.check_invariants(cx);
3595    }
3596
3597    fn check_invariants(&self, cx: &App) {
3598        self.read(cx).check_invariants();
3599    }
3600}
3601
3602impl EventEmitter<Event> for MultiBuffer {}
3603
3604impl MultiBufferSnapshot {
3605    pub fn text(&self) -> String {
3606        self.chunks(0..self.len(), false)
3607            .map(|chunk| chunk.text)
3608            .collect()
3609    }
3610
3611    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3612        self.reversed_chunks_in_range(0..position.to_offset(self))
3613            .flat_map(|c| c.chars().rev())
3614    }
3615
3616    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3617        let mut cursor = self.cursor::<usize>();
3618        cursor.seek(&range.end);
3619        let current_chunks = cursor.region().as_ref().map(|region| {
3620            let start_overshoot = range.start.saturating_sub(region.range.start);
3621            let end_overshoot = range.end - region.range.start;
3622            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3623            let start = region.buffer_range.start + start_overshoot;
3624            region.buffer.reversed_chunks_in_range(start..end)
3625        });
3626        ReversedMultiBufferChunks {
3627            cursor,
3628            current_chunks,
3629            start: range.start,
3630            offset: range.end,
3631        }
3632    }
3633
3634    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3635        let offset = position.to_offset(self);
3636        self.text_for_range(offset..self.len())
3637            .flat_map(|chunk| chunk.chars())
3638    }
3639
3640    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3641        self.chunks(range, false).map(|chunk| chunk.text)
3642    }
3643
3644    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3645        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3646            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3647    }
3648
3649    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3650    where
3651        T: ToOffset,
3652    {
3653        let position = position.to_offset(self);
3654        position == self.clip_offset(position, Bias::Left)
3655            && self
3656                .bytes_in_range(position..self.len())
3657                .flatten()
3658                .copied()
3659                .take(needle.len())
3660                .eq(needle.bytes())
3661    }
3662
3663    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3664        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3665    }
3666
3667    pub fn diff_hunks_in_range<T: ToPoint>(
3668        &self,
3669        range: Range<T>,
3670    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3671        let query_range = range.start.to_point(self)..range.end.to_point(self);
3672        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3673            let diff = self.diffs.get(&buffer.remote_id())?;
3674            let buffer_start = buffer.anchor_before(buffer_range.start);
3675            let buffer_end = buffer.anchor_after(buffer_range.end);
3676            Some(
3677                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3678                    .filter_map(|hunk| {
3679                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3680                            return None;
3681                        }
3682                        Some((hunk.range.clone(), hunk))
3683                    }),
3684            )
3685        })
3686        .filter_map(move |(range, hunk, excerpt)| {
3687            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3688            {
3689                return None;
3690            }
3691            let end_row = if range.end.column == 0 {
3692                range.end.row
3693            } else {
3694                range.end.row + 1
3695            };
3696            Some(MultiBufferDiffHunk {
3697                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3698                buffer_id: excerpt.buffer_id,
3699                excerpt_id: excerpt.id,
3700                buffer_range: hunk.buffer_range.clone(),
3701                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3702                secondary_status: hunk.secondary_status,
3703            })
3704        })
3705    }
3706
3707    pub fn excerpt_ids_for_range<T: ToOffset>(
3708        &self,
3709        range: Range<T>,
3710    ) -> impl Iterator<Item = ExcerptId> + '_ {
3711        let range = range.start.to_offset(self)..range.end.to_offset(self);
3712        let mut cursor = self.cursor::<usize>();
3713        cursor.seek(&range.start);
3714        std::iter::from_fn(move || {
3715            let region = cursor.region()?;
3716            if region.range.start >= range.end {
3717                return None;
3718            }
3719            cursor.next_excerpt();
3720            Some(region.excerpt.id)
3721        })
3722    }
3723
3724    pub fn buffer_ids_for_range<T: ToOffset>(
3725        &self,
3726        range: Range<T>,
3727    ) -> impl Iterator<Item = BufferId> + '_ {
3728        let range = range.start.to_offset(self)..range.end.to_offset(self);
3729        let mut cursor = self.cursor::<usize>();
3730        cursor.seek(&range.start);
3731        std::iter::from_fn(move || {
3732            let region = cursor.region()?;
3733            if region.range.start > range.end
3734                || region.range.start == range.end && region.range.start > range.start
3735            {
3736                return None;
3737            }
3738            cursor.next_excerpt();
3739            Some(region.excerpt.buffer_id)
3740        })
3741    }
3742
3743    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3744        &self,
3745        ranges: impl Iterator<Item = Range<T>>,
3746    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3747        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3748    }
3749
3750    pub fn range_to_buffer_ranges<T: ToOffset>(
3751        &self,
3752        range: Range<T>,
3753    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3754        let start = range.start.to_offset(&self);
3755        let end = range.end.to_offset(&self);
3756
3757        let mut cursor = self.cursor::<usize>();
3758        cursor.seek(&start);
3759
3760        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3761        while let Some(region) = cursor.region() {
3762            if region.range.start > end {
3763                break;
3764            }
3765            if region.is_main_buffer {
3766                let start_overshoot = start.saturating_sub(region.range.start);
3767                let end_overshoot = end.saturating_sub(region.range.start);
3768                let start = region
3769                    .buffer_range
3770                    .end
3771                    .min(region.buffer_range.start + start_overshoot);
3772                let end = region
3773                    .buffer_range
3774                    .end
3775                    .min(region.buffer_range.start + end_overshoot);
3776                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3777                    *excerpt_id == region.excerpt.id && prev_range.end == start
3778                }) {
3779                    prev.1.end = end;
3780                } else {
3781                    result.push((region.buffer, start..end, region.excerpt.id));
3782                }
3783            }
3784            cursor.next();
3785        }
3786        result
3787    }
3788
3789    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3790        &self,
3791        range: Range<T>,
3792    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3793        let start = range.start.to_offset(&self);
3794        let end = range.end.to_offset(&self);
3795
3796        let mut cursor = self.cursor::<usize>();
3797        cursor.seek(&start);
3798
3799        std::iter::from_fn(move || {
3800            let region = cursor.region()?;
3801            if region.range.start > end {
3802                return None;
3803            }
3804            let start_overshoot = start.saturating_sub(region.range.start);
3805            let end_overshoot = end.saturating_sub(region.range.start);
3806            let start = region
3807                .buffer_range
3808                .end
3809                .min(region.buffer_range.start + start_overshoot);
3810            let end = region
3811                .buffer_range
3812                .end
3813                .min(region.buffer_range.start + end_overshoot);
3814
3815            let region_excerpt_id = region.excerpt.id;
3816            let deleted_hunk_anchor = if region.is_main_buffer {
3817                None
3818            } else {
3819                Some(self.anchor_before(region.range.start))
3820            };
3821            let result = (
3822                region.buffer,
3823                start..end,
3824                region_excerpt_id,
3825                deleted_hunk_anchor,
3826            );
3827            cursor.next();
3828            Some(result)
3829        })
3830    }
3831
3832    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3833    /// coordinates.
3834    ///
3835    /// The given callback will be called for every excerpt intersecting the given range. It will
3836    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3837    /// The callback should return an iterator of metadata items from that buffer, each paired
3838    /// with a buffer range.
3839    ///
3840    /// The returned iterator yields each of these metadata items, paired with its range in
3841    /// multi-buffer coordinates.
3842    fn lift_buffer_metadata<'a, D, M, I>(
3843        &'a self,
3844        query_range: Range<D>,
3845        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3846    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3847    where
3848        I: Iterator<Item = (Range<D>, M)> + 'a,
3849        D: TextDimension + Ord + Sub<D, Output = D>,
3850    {
3851        let max_position = D::from_text_summary(&self.text_summary());
3852        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3853        let mut cursor = self.cursor::<D>();
3854
3855        // Find the excerpt and buffer offset where the given range ends.
3856        cursor.seek(&query_range.end);
3857        let mut range_end = None;
3858        while let Some(region) = cursor.region() {
3859            if region.is_main_buffer {
3860                let mut buffer_end = region.buffer_range.start;
3861                let overshoot = if query_range.end > region.range.start {
3862                    query_range.end - region.range.start
3863                } else {
3864                    D::default()
3865                };
3866                buffer_end.add_assign(&overshoot);
3867                range_end = Some((region.excerpt.id, buffer_end));
3868                break;
3869            }
3870            cursor.next();
3871        }
3872
3873        cursor.seek(&query_range.start);
3874
3875        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3876            if region.range.start > D::zero(&()) {
3877                cursor.prev()
3878            }
3879        }
3880
3881        iter::from_fn(move || loop {
3882            let excerpt = cursor.excerpt()?;
3883
3884            // If we have already retrieved metadata for this excerpt, continue to use it.
3885            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3886                .as_mut()
3887                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3888            {
3889                Some(metadata)
3890            }
3891            // Otherwise, compute the intersection of the input range with the excerpt's range,
3892            // and retrieve the metadata for the resulting range.
3893            else {
3894                let region = cursor.region()?;
3895                let mut buffer_start;
3896                if region.is_main_buffer {
3897                    buffer_start = region.buffer_range.start;
3898                    if query_range.start > region.range.start {
3899                        let overshoot = query_range.start - region.range.start;
3900                        buffer_start.add_assign(&overshoot);
3901                    }
3902                    buffer_start = buffer_start.min(region.buffer_range.end);
3903                } else {
3904                    buffer_start = cursor.main_buffer_position()?;
3905                };
3906                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3907                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3908                    if excerpt.id == end_excerpt_id {
3909                        buffer_end = buffer_end.min(end_buffer_offset);
3910                    }
3911                }
3912
3913                if let Some(iterator) =
3914                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3915                {
3916                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3917                } else {
3918                    None
3919                }
3920            };
3921
3922            // Visit each metadata item.
3923            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3924            {
3925                // Find the multibuffer regions that contain the start and end of
3926                // the metadata item's range.
3927                if metadata_buffer_range.start > D::default() {
3928                    while let Some(region) = cursor.region() {
3929                        if region.is_main_buffer
3930                            && (region.buffer_range.end >= metadata_buffer_range.start
3931                                || cursor.is_at_end_of_excerpt())
3932                        {
3933                            break;
3934                        }
3935                        cursor.next();
3936                    }
3937                }
3938                let start_region = cursor.region()?;
3939                while let Some(region) = cursor.region() {
3940                    if region.is_main_buffer
3941                        && (region.buffer_range.end > metadata_buffer_range.end
3942                            || cursor.is_at_end_of_excerpt())
3943                    {
3944                        break;
3945                    }
3946                    cursor.next();
3947                }
3948                let end_region = cursor.region();
3949
3950                // Convert the metadata item's range into multibuffer coordinates.
3951                let mut start_position = start_region.range.start;
3952                let region_buffer_start = start_region.buffer_range.start;
3953                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3954                {
3955                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3956                    start_position = start_position.min(start_region.range.end);
3957                }
3958
3959                let mut end_position = max_position;
3960                if let Some(end_region) = &end_region {
3961                    end_position = end_region.range.start;
3962                    debug_assert!(end_region.is_main_buffer);
3963                    let region_buffer_start = end_region.buffer_range.start;
3964                    if metadata_buffer_range.end > region_buffer_start {
3965                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3966                    }
3967                    end_position = end_position.min(end_region.range.end);
3968                }
3969
3970                if start_position <= query_range.end && end_position >= query_range.start {
3971                    return Some((start_position..end_position, metadata, excerpt));
3972                }
3973            }
3974            // When there are no more metadata items for this excerpt, move to the next excerpt.
3975            else {
3976                current_excerpt_metadata.take();
3977                if let Some((end_excerpt_id, _)) = range_end {
3978                    if excerpt.id == end_excerpt_id {
3979                        return None;
3980                    }
3981                }
3982                cursor.next_excerpt();
3983            }
3984        })
3985    }
3986
3987    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3988        let offset = position.to_offset(self);
3989
3990        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3991        cursor.seek(&DimensionPair {
3992            key: offset,
3993            value: None,
3994        });
3995        cursor.seek_to_start_of_current_excerpt();
3996        let excerpt = cursor.excerpt()?;
3997
3998        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3999        let current_position = self
4000            .anchor_before(offset)
4001            .text_anchor
4002            .to_offset(&excerpt.buffer);
4003        let excerpt_end = excerpt
4004            .buffer
4005            .anchor_before(excerpt_end.min(current_position));
4006
4007        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4008            for hunk in diff.hunks_intersecting_range_rev(
4009                excerpt.range.context.start..excerpt_end,
4010                &excerpt.buffer,
4011            ) {
4012                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4013                if hunk_end >= current_position {
4014                    continue;
4015                }
4016                let start =
4017                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4018                        .to_point(&self);
4019                return Some(MultiBufferRow(start.row));
4020            }
4021        }
4022
4023        loop {
4024            cursor.prev_excerpt();
4025            let excerpt = cursor.excerpt()?;
4026
4027            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4028                continue;
4029            };
4030            let mut hunks =
4031                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4032            let Some(hunk) = hunks.next() else {
4033                continue;
4034            };
4035            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4036                .to_point(&self);
4037            return Some(MultiBufferRow(start.row));
4038        }
4039    }
4040
4041    pub fn has_diff_hunks(&self) -> bool {
4042        self.diffs.values().any(|diff| !diff.is_empty())
4043    }
4044
4045    pub fn surrounding_word<T: ToOffset>(
4046        &self,
4047        start: T,
4048        for_completion: bool,
4049    ) -> (Range<usize>, Option<CharKind>) {
4050        let mut start = start.to_offset(self);
4051        let mut end = start;
4052        let mut next_chars = self.chars_at(start).peekable();
4053        let mut prev_chars = self.reversed_chars_at(start).peekable();
4054
4055        let classifier = self
4056            .char_classifier_at(start)
4057            .for_completion(for_completion);
4058
4059        let word_kind = cmp::max(
4060            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4061            next_chars.peek().copied().map(|c| classifier.kind(c)),
4062        );
4063
4064        for ch in prev_chars {
4065            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4066                start -= ch.len_utf8();
4067            } else {
4068                break;
4069            }
4070        }
4071
4072        for ch in next_chars {
4073            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4074                end += ch.len_utf8();
4075            } else {
4076                break;
4077            }
4078        }
4079
4080        (start..end, word_kind)
4081    }
4082
4083    pub fn is_singleton(&self) -> bool {
4084        self.singleton
4085    }
4086
4087    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4088        if self.singleton {
4089            self.excerpts
4090                .iter()
4091                .next()
4092                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4093        } else {
4094            None
4095        }
4096    }
4097
4098    pub fn len(&self) -> usize {
4099        self.diff_transforms.summary().output.len
4100    }
4101
4102    pub fn is_empty(&self) -> bool {
4103        self.excerpts.summary().text.len == 0
4104    }
4105
4106    pub fn widest_line_number(&self) -> u32 {
4107        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4108        self.excerpts.summary().widest_line_number + 1
4109    }
4110
4111    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
4112        let range = range.start.to_offset(self)..range.end.to_offset(self);
4113        let mut excerpts = self.cursor::<usize>();
4114        excerpts.seek(&range.start);
4115
4116        let mut chunk;
4117        let mut has_trailing_newline;
4118        let excerpt_bytes;
4119        if let Some(region) = excerpts.region() {
4120            let mut bytes = region.buffer.bytes_in_range(
4121                region.buffer_range.start + range.start - region.range.start
4122                    ..(region.buffer_range.start + range.end - region.range.start)
4123                        .min(region.buffer_range.end),
4124            );
4125            chunk = bytes.next().unwrap_or(&[][..]);
4126            excerpt_bytes = Some(bytes);
4127            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4128            if chunk.is_empty() && has_trailing_newline {
4129                chunk = b"\n";
4130                has_trailing_newline = false;
4131            }
4132        } else {
4133            chunk = &[][..];
4134            excerpt_bytes = None;
4135            has_trailing_newline = false;
4136        };
4137
4138        MultiBufferBytes {
4139            range,
4140            cursor: excerpts,
4141            excerpt_bytes,
4142            has_trailing_newline,
4143            chunk,
4144        }
4145    }
4146
4147    pub fn reversed_bytes_in_range<T: ToOffset>(
4148        &self,
4149        range: Range<T>,
4150    ) -> ReversedMultiBufferBytes {
4151        let range = range.start.to_offset(self)..range.end.to_offset(self);
4152        let mut chunks = self.reversed_chunks_in_range(range.clone());
4153        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4154        ReversedMultiBufferBytes {
4155            range,
4156            chunks,
4157            chunk,
4158        }
4159    }
4160
4161    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4162        let mut cursor = self.cursor::<Point>();
4163        cursor.seek(&Point::new(start_row.0, 0));
4164        let mut result = MultiBufferRows {
4165            point: Point::new(0, 0),
4166            is_empty: self.excerpts.is_empty(),
4167            is_singleton: self.is_singleton(),
4168            cursor,
4169        };
4170        result.seek(start_row);
4171        result
4172    }
4173
4174    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4175        let mut chunks = MultiBufferChunks {
4176            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4177            range: 0..0,
4178            excerpts: self.excerpts.cursor(&()),
4179            diff_transforms: self.diff_transforms.cursor(&()),
4180            diffs: &self.diffs,
4181            diff_base_chunks: None,
4182            excerpt_chunks: None,
4183            buffer_chunk: None,
4184            language_aware,
4185        };
4186        let range = range.start.to_offset(self)..range.end.to_offset(self);
4187        chunks.seek(range);
4188        chunks
4189    }
4190
4191    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4192        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4193    }
4194
4195    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4196        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4197    }
4198
4199    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4200        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4201    }
4202
4203    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4204        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4205            buffer.clip_point_utf16(Unclipped(point), bias)
4206        })
4207    }
4208
4209    pub fn offset_to_point(&self, offset: usize) -> Point {
4210        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4211    }
4212
4213    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4214        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4215    }
4216
4217    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4218        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4219    }
4220
4221    pub fn point_to_offset(&self, point: Point) -> usize {
4222        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4223    }
4224
4225    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4226        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4227    }
4228
4229    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4230        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4231    }
4232
4233    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4234        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4235    }
4236
4237    fn clip_dimension<D>(
4238        &self,
4239        position: D,
4240        bias: Bias,
4241        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4242    ) -> D
4243    where
4244        D: TextDimension + Ord + Sub<D, Output = D>,
4245    {
4246        let mut cursor = self.cursor();
4247        cursor.seek(&position);
4248        if let Some(region) = cursor.region() {
4249            if position >= region.range.end {
4250                return region.range.end;
4251            }
4252            let overshoot = position - region.range.start;
4253            let mut buffer_position = region.buffer_range.start;
4254            buffer_position.add_assign(&overshoot);
4255            let clipped_buffer_position =
4256                clip_buffer_position(&region.buffer, buffer_position, bias);
4257            let mut position = region.range.start;
4258            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4259            position
4260        } else {
4261            D::from_text_summary(&self.text_summary())
4262        }
4263    }
4264
4265    fn convert_dimension<D1, D2>(
4266        &self,
4267        key: D1,
4268        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4269    ) -> D2
4270    where
4271        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4272        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4273    {
4274        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4275        cursor.seek(&DimensionPair { key, value: None });
4276        if let Some(region) = cursor.region() {
4277            if key >= region.range.end.key {
4278                return region.range.end.value.unwrap();
4279            }
4280            let start_key = region.range.start.key;
4281            let start_value = region.range.start.value.unwrap();
4282            let buffer_start_key = region.buffer_range.start.key;
4283            let buffer_start_value = region.buffer_range.start.value.unwrap();
4284            let mut buffer_key = buffer_start_key;
4285            buffer_key.add_assign(&(key - start_key));
4286            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4287            let mut result = start_value;
4288            result.add_assign(&(buffer_value - buffer_start_value));
4289            result
4290        } else {
4291            D2::from_text_summary(&self.text_summary())
4292        }
4293    }
4294
4295    pub fn point_to_buffer_offset<T: ToOffset>(
4296        &self,
4297        point: T,
4298    ) -> Option<(&BufferSnapshot, usize)> {
4299        let offset = point.to_offset(self);
4300        let mut cursor = self.cursor::<usize>();
4301        cursor.seek(&offset);
4302        let region = cursor.region()?;
4303        let overshoot = offset - region.range.start;
4304        let buffer_offset = region.buffer_range.start + overshoot;
4305        if buffer_offset == region.buffer.len() + 1
4306            && region.has_trailing_newline
4307            && !region.is_main_buffer
4308        {
4309            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4310        } else if buffer_offset > region.buffer.len() {
4311            return None;
4312        }
4313        Some((region.buffer, buffer_offset))
4314    }
4315
4316    pub fn point_to_buffer_point(
4317        &self,
4318        point: Point,
4319    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4320        let mut cursor = self.cursor::<Point>();
4321        cursor.seek(&point);
4322        let region = cursor.region()?;
4323        let overshoot = point - region.range.start;
4324        let buffer_point = region.buffer_range.start + overshoot;
4325        let excerpt = cursor.excerpt()?;
4326        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4327            && region.has_trailing_newline
4328            && !region.is_main_buffer
4329        {
4330            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4331        } else if buffer_point > region.buffer.max_point() {
4332            return None;
4333        }
4334        Some((region.buffer, buffer_point, excerpt.id))
4335    }
4336
4337    pub fn suggested_indents(
4338        &self,
4339        rows: impl IntoIterator<Item = u32>,
4340        cx: &App,
4341    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4342        let mut result = BTreeMap::new();
4343
4344        let mut rows_for_excerpt = Vec::new();
4345        let mut cursor = self.cursor::<Point>();
4346        let mut rows = rows.into_iter().peekable();
4347        let mut prev_row = u32::MAX;
4348        let mut prev_language_indent_size = IndentSize::default();
4349
4350        while let Some(row) = rows.next() {
4351            cursor.seek(&Point::new(row, 0));
4352            let Some(region) = cursor.region() else {
4353                continue;
4354            };
4355
4356            // Retrieve the language and indent size once for each disjoint region being indented.
4357            let single_indent_size = if row.saturating_sub(1) == prev_row {
4358                prev_language_indent_size
4359            } else {
4360                region
4361                    .buffer
4362                    .language_indent_size_at(Point::new(row, 0), cx)
4363            };
4364            prev_language_indent_size = single_indent_size;
4365            prev_row = row;
4366
4367            let start_buffer_row = region.buffer_range.start.row;
4368            let start_multibuffer_row = region.range.start.row;
4369            let end_multibuffer_row = region.range.end.row;
4370
4371            rows_for_excerpt.push(row);
4372            while let Some(next_row) = rows.peek().copied() {
4373                if end_multibuffer_row > next_row {
4374                    rows_for_excerpt.push(next_row);
4375                    rows.next();
4376                } else {
4377                    break;
4378                }
4379            }
4380
4381            let buffer_rows = rows_for_excerpt
4382                .drain(..)
4383                .map(|row| start_buffer_row + row - start_multibuffer_row);
4384            let buffer_indents = region
4385                .buffer
4386                .suggested_indents(buffer_rows, single_indent_size);
4387            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4388                (
4389                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4390                    indent,
4391                )
4392            });
4393            result.extend(multibuffer_indents);
4394        }
4395
4396        result
4397    }
4398
4399    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4400        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4401            let mut size = buffer.indent_size_for_line(range.start.row);
4402            size.len = size
4403                .len
4404                .min(range.end.column)
4405                .saturating_sub(range.start.column);
4406            size
4407        } else {
4408            IndentSize::spaces(0)
4409        }
4410    }
4411
4412    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4413        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4414            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4415        } else {
4416            LineIndent::spaces(0)
4417        }
4418    }
4419
4420    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4421        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4422
4423        if self.language_settings(cx).extend_comment_on_newline {
4424            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4425                let delimiters = language_scope.line_comment_prefixes();
4426                for delimiter in delimiters {
4427                    if *self
4428                        .chars_at(Point::new(row.0, indent.len() as u32))
4429                        .take(delimiter.chars().count())
4430                        .collect::<String>()
4431                        .as_str()
4432                        == **delimiter
4433                    {
4434                        indent.push_str(&delimiter);
4435                        break;
4436                    }
4437                }
4438            }
4439        }
4440
4441        indent
4442    }
4443
4444    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4445    where
4446        T: ToOffset,
4447    {
4448        for char in self.reversed_chars_at(position) {
4449            if !char.is_whitespace() {
4450                return false;
4451            }
4452            if char == '\n' {
4453                return true;
4454            }
4455        }
4456        return true;
4457    }
4458
4459    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4460        while row.0 > 0 {
4461            row.0 -= 1;
4462            if !self.is_line_blank(row) {
4463                return Some(row);
4464            }
4465        }
4466        None
4467    }
4468
4469    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4470        if let Some((_, range)) = self.buffer_line_for_row(row) {
4471            range.end.column - range.start.column
4472        } else {
4473            0
4474        }
4475    }
4476
4477    pub fn buffer_line_for_row(
4478        &self,
4479        row: MultiBufferRow,
4480    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4481        let mut cursor = self.cursor::<Point>();
4482        let point = Point::new(row.0, 0);
4483        cursor.seek(&point);
4484        let region = cursor.region()?;
4485        let overshoot = point.min(region.range.end) - region.range.start;
4486        let buffer_point = region.buffer_range.start + overshoot;
4487        if buffer_point.row > region.buffer_range.end.row {
4488            return None;
4489        }
4490        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4491        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4492            .min(region.buffer_range.end);
4493        Some((region.buffer, line_start..line_end))
4494    }
4495
4496    pub fn max_point(&self) -> Point {
4497        self.text_summary().lines
4498    }
4499
4500    pub fn max_row(&self) -> MultiBufferRow {
4501        MultiBufferRow(self.text_summary().lines.row)
4502    }
4503
4504    pub fn text_summary(&self) -> TextSummary {
4505        self.diff_transforms.summary().output
4506    }
4507
4508    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4509    where
4510        D: TextDimension,
4511        O: ToOffset,
4512    {
4513        let range = range.start.to_offset(self)..range.end.to_offset(self);
4514        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4515        cursor.seek(&range.start, Bias::Right, &());
4516
4517        let Some(first_transform) = cursor.item() else {
4518            return D::from_text_summary(&TextSummary::default());
4519        };
4520
4521        let diff_transform_start = cursor.start().0;
4522        let diff_transform_end = cursor.end(&()).0;
4523        let diff_start = range.start;
4524        let start_overshoot = diff_start - diff_transform_start;
4525        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4526
4527        let mut result = match first_transform {
4528            DiffTransform::BufferContent { .. } => {
4529                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4530                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4531                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4532            }
4533            DiffTransform::DeletedHunk {
4534                buffer_id,
4535                base_text_byte_range,
4536                has_trailing_newline,
4537                ..
4538            } => {
4539                let buffer_start = base_text_byte_range.start + start_overshoot;
4540                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4541                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4542                    panic!("{:?} is in non-existent deleted hunk", range.start)
4543                };
4544
4545                let include_trailing_newline =
4546                    *has_trailing_newline && range.end >= diff_transform_end;
4547                if include_trailing_newline {
4548                    buffer_end -= 1;
4549                }
4550
4551                let mut summary =
4552                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4553
4554                if include_trailing_newline {
4555                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4556                }
4557
4558                summary
4559            }
4560        };
4561        if range.end < diff_transform_end {
4562            return result;
4563        }
4564
4565        cursor.next(&());
4566        result.add_assign(&D::from_text_summary(&cursor.summary(
4567            &range.end,
4568            Bias::Right,
4569            &(),
4570        )));
4571
4572        let Some(last_transform) = cursor.item() else {
4573            return result;
4574        };
4575
4576        let overshoot = range.end - cursor.start().0;
4577        let suffix = match last_transform {
4578            DiffTransform::BufferContent { .. } => {
4579                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4580                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4581            }
4582            DiffTransform::DeletedHunk {
4583                base_text_byte_range,
4584                buffer_id,
4585                has_trailing_newline,
4586                ..
4587            } => {
4588                let buffer_end = base_text_byte_range.start + overshoot;
4589                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4590                    panic!("{:?} is in non-existent deleted hunk", range.end)
4591                };
4592
4593                let mut suffix = base_text
4594                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4595                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4596                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4597                }
4598                suffix
4599            }
4600        };
4601
4602        result.add_assign(&suffix);
4603        result
4604    }
4605
4606    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4607    where
4608        D: TextDimension,
4609    {
4610        // let mut range = range.start..range.end;
4611        let mut summary = D::zero(&());
4612        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4613        cursor.seek(&range.start, Bias::Right, &());
4614        if let Some(excerpt) = cursor.item() {
4615            let mut end_before_newline = cursor.end(&());
4616            if excerpt.has_trailing_newline {
4617                end_before_newline -= ExcerptOffset::new(1);
4618            }
4619
4620            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4621            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4622            let end_in_excerpt =
4623                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4624            summary.add_assign(
4625                &excerpt
4626                    .buffer
4627                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4628            );
4629
4630            if range.end > end_before_newline {
4631                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4632            }
4633
4634            cursor.next(&());
4635        }
4636
4637        if range.end > *cursor.start() {
4638            summary.add_assign(
4639                &cursor
4640                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4641                    .0,
4642            );
4643            if let Some(excerpt) = cursor.item() {
4644                range.end = cmp::max(*cursor.start(), range.end);
4645
4646                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4647                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4648                summary.add_assign(
4649                    &excerpt
4650                        .buffer
4651                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4652                );
4653            }
4654        }
4655
4656        summary
4657    }
4658
4659    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4660    where
4661        D: TextDimension + Ord + Sub<D, Output = D>,
4662    {
4663        self.summaries_for_anchors([anchor])[0]
4664    }
4665
4666    fn resolve_summary_for_anchor<D>(
4667        &self,
4668        anchor: &Anchor,
4669        excerpt_position: D,
4670        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4671    ) -> D
4672    where
4673        D: TextDimension + Ord + Sub<D, Output = D>,
4674    {
4675        loop {
4676            let transform_end_position = diff_transforms.end(&()).0 .0;
4677            let at_transform_end =
4678                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4679            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4680                diff_transforms.next(&());
4681                continue;
4682            }
4683
4684            let mut position = diff_transforms.start().1 .0;
4685            match diff_transforms.item() {
4686                Some(DiffTransform::DeletedHunk {
4687                    buffer_id,
4688                    base_text_byte_range,
4689                    ..
4690                }) => {
4691                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4692                        if let Some(base_text) =
4693                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4694                        {
4695                            if base_text.can_resolve(&diff_base_anchor) {
4696                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4697                                if base_text_offset >= base_text_byte_range.start
4698                                    && base_text_offset <= base_text_byte_range.end
4699                                {
4700                                    let position_in_hunk = base_text
4701                                        .text_summary_for_range::<D, _>(
4702                                            base_text_byte_range.start..base_text_offset,
4703                                        );
4704                                    position.add_assign(&position_in_hunk);
4705                                } else if at_transform_end {
4706                                    diff_transforms.next(&());
4707                                    continue;
4708                                }
4709                            }
4710                        }
4711                    }
4712                }
4713                _ => {
4714                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4715                        diff_transforms.next(&());
4716                        continue;
4717                    }
4718                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4719                    position.add_assign(&overshoot);
4720                }
4721            }
4722
4723            return position;
4724        }
4725    }
4726
4727    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4728        let mut cursor = self
4729            .excerpts
4730            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4731        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4732
4733        cursor.seek(&Some(locator), Bias::Left, &());
4734        if cursor.item().is_none() {
4735            cursor.next(&());
4736        }
4737
4738        let mut position = cursor.start().1;
4739        if let Some(excerpt) = cursor.item() {
4740            if excerpt.id == anchor.excerpt_id {
4741                let excerpt_buffer_start = excerpt
4742                    .buffer
4743                    .offset_for_anchor(&excerpt.range.context.start);
4744                let excerpt_buffer_end =
4745                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4746                let buffer_position = cmp::min(
4747                    excerpt_buffer_end,
4748                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4749                );
4750                if buffer_position > excerpt_buffer_start {
4751                    position.value += buffer_position - excerpt_buffer_start;
4752                }
4753            }
4754        }
4755        position
4756    }
4757
4758    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4759    where
4760        D: TextDimension + Ord + Sub<D, Output = D>,
4761        I: 'a + IntoIterator<Item = &'a Anchor>,
4762    {
4763        let mut anchors = anchors.into_iter().peekable();
4764        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4765        let mut diff_transforms_cursor = self
4766            .diff_transforms
4767            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4768        diff_transforms_cursor.next(&());
4769
4770        let mut summaries = Vec::new();
4771        while let Some(anchor) = anchors.peek() {
4772            let excerpt_id = anchor.excerpt_id;
4773            let excerpt_anchors = iter::from_fn(|| {
4774                let anchor = anchors.peek()?;
4775                if anchor.excerpt_id == excerpt_id {
4776                    Some(anchors.next().unwrap())
4777                } else {
4778                    None
4779                }
4780            });
4781
4782            let locator = self.excerpt_locator_for_id(excerpt_id);
4783            cursor.seek_forward(locator, Bias::Left, &());
4784            if cursor.item().is_none() {
4785                cursor.next(&());
4786            }
4787
4788            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4789            if let Some(excerpt) = cursor.item() {
4790                if excerpt.id != excerpt_id {
4791                    let position = self.resolve_summary_for_anchor(
4792                        &Anchor::min(),
4793                        excerpt_start_position,
4794                        &mut diff_transforms_cursor,
4795                    );
4796                    summaries.extend(excerpt_anchors.map(|_| position));
4797                    continue;
4798                }
4799                let excerpt_buffer_start =
4800                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4801                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4802                for (buffer_summary, anchor) in excerpt
4803                    .buffer
4804                    .summaries_for_anchors_with_payload::<D, _, _>(
4805                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4806                    )
4807                {
4808                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4809                    let mut position = excerpt_start_position;
4810                    if summary > excerpt_buffer_start {
4811                        position.add_assign(&(summary - excerpt_buffer_start));
4812                    }
4813
4814                    if position > diff_transforms_cursor.start().0 .0 {
4815                        diff_transforms_cursor.seek_forward(
4816                            &ExcerptDimension(position),
4817                            Bias::Left,
4818                            &(),
4819                        );
4820                    }
4821
4822                    summaries.push(self.resolve_summary_for_anchor(
4823                        anchor,
4824                        position,
4825                        &mut diff_transforms_cursor,
4826                    ));
4827                }
4828            } else {
4829                diff_transforms_cursor.seek_forward(
4830                    &ExcerptDimension(excerpt_start_position),
4831                    Bias::Left,
4832                    &(),
4833                );
4834                let position = self.resolve_summary_for_anchor(
4835                    &Anchor::max(),
4836                    excerpt_start_position,
4837                    &mut diff_transforms_cursor,
4838                );
4839                summaries.extend(excerpt_anchors.map(|_| position));
4840            }
4841        }
4842
4843        summaries
4844    }
4845
4846    pub fn dimensions_from_points<'a, D>(
4847        &'a self,
4848        points: impl 'a + IntoIterator<Item = Point>,
4849    ) -> impl 'a + Iterator<Item = D>
4850    where
4851        D: TextDimension + Sub<D, Output = D>,
4852    {
4853        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4854        cursor.seek(&DimensionPair {
4855            key: Point::default(),
4856            value: None,
4857        });
4858        let mut points = points.into_iter();
4859        iter::from_fn(move || {
4860            let point = points.next()?;
4861
4862            cursor.seek_forward(&DimensionPair {
4863                key: point,
4864                value: None,
4865            });
4866
4867            if let Some(region) = cursor.region() {
4868                let overshoot = point - region.range.start.key;
4869                let buffer_point = region.buffer_range.start.key + overshoot;
4870                let mut position = region.range.start.value.unwrap();
4871                position.add_assign(
4872                    &region
4873                        .buffer
4874                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4875                );
4876                if point == region.range.end.key && region.has_trailing_newline {
4877                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4878                }
4879                return Some(position);
4880            } else {
4881                return Some(D::from_text_summary(&self.text_summary()));
4882            }
4883        })
4884    }
4885
4886    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4887    where
4888        I: 'a + IntoIterator<Item = &'a Anchor>,
4889    {
4890        let mut anchors = anchors.into_iter().enumerate().peekable();
4891        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4892        cursor.next(&());
4893
4894        let mut result = Vec::new();
4895
4896        while let Some((_, anchor)) = anchors.peek() {
4897            let old_excerpt_id = anchor.excerpt_id;
4898
4899            // Find the location where this anchor's excerpt should be.
4900            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4901            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4902
4903            if cursor.item().is_none() {
4904                cursor.next(&());
4905            }
4906
4907            let next_excerpt = cursor.item();
4908            let prev_excerpt = cursor.prev_item();
4909
4910            // Process all of the anchors for this excerpt.
4911            while let Some((_, anchor)) = anchors.peek() {
4912                if anchor.excerpt_id != old_excerpt_id {
4913                    break;
4914                }
4915                let (anchor_ix, anchor) = anchors.next().unwrap();
4916                let mut anchor = *anchor;
4917
4918                // Leave min and max anchors unchanged if invalid or
4919                // if the old excerpt still exists at this location
4920                let mut kept_position = next_excerpt
4921                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4922                    || old_excerpt_id == ExcerptId::max()
4923                    || old_excerpt_id == ExcerptId::min();
4924
4925                // If the old excerpt no longer exists at this location, then attempt to
4926                // find an equivalent position for this anchor in an adjacent excerpt.
4927                if !kept_position {
4928                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4929                        if excerpt.contains(&anchor) {
4930                            anchor.excerpt_id = excerpt.id;
4931                            kept_position = true;
4932                            break;
4933                        }
4934                    }
4935                }
4936
4937                // If there's no adjacent excerpt that contains the anchor's position,
4938                // then report that the anchor has lost its position.
4939                if !kept_position {
4940                    anchor = if let Some(excerpt) = next_excerpt {
4941                        let mut text_anchor = excerpt
4942                            .range
4943                            .context
4944                            .start
4945                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4946                        if text_anchor
4947                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4948                            .is_gt()
4949                        {
4950                            text_anchor = excerpt.range.context.end;
4951                        }
4952                        Anchor {
4953                            buffer_id: Some(excerpt.buffer_id),
4954                            excerpt_id: excerpt.id,
4955                            text_anchor,
4956                            diff_base_anchor: None,
4957                        }
4958                    } else if let Some(excerpt) = prev_excerpt {
4959                        let mut text_anchor = excerpt
4960                            .range
4961                            .context
4962                            .end
4963                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4964                        if text_anchor
4965                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4966                            .is_lt()
4967                        {
4968                            text_anchor = excerpt.range.context.start;
4969                        }
4970                        Anchor {
4971                            buffer_id: Some(excerpt.buffer_id),
4972                            excerpt_id: excerpt.id,
4973                            text_anchor,
4974                            diff_base_anchor: None,
4975                        }
4976                    } else if anchor.text_anchor.bias == Bias::Left {
4977                        Anchor::min()
4978                    } else {
4979                        Anchor::max()
4980                    };
4981                }
4982
4983                result.push((anchor_ix, anchor, kept_position));
4984            }
4985        }
4986        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4987        result
4988    }
4989
4990    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4991        self.anchor_at(position, Bias::Left)
4992    }
4993
4994    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4995        self.anchor_at(position, Bias::Right)
4996    }
4997
4998    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4999        let offset = position.to_offset(self);
5000
5001        // Find the given position in the diff transforms. Determine the corresponding
5002        // offset in the excerpts, and whether the position is within a deleted hunk.
5003        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
5004        diff_transforms.seek(&offset, Bias::Right, &());
5005
5006        if offset == diff_transforms.start().0 && bias == Bias::Left {
5007            if let Some(prev_item) = diff_transforms.prev_item() {
5008                match prev_item {
5009                    DiffTransform::DeletedHunk { .. } => {
5010                        diff_transforms.prev(&());
5011                    }
5012                    _ => {}
5013                }
5014            }
5015        }
5016        let offset_in_transform = offset - diff_transforms.start().0;
5017        let mut excerpt_offset = diff_transforms.start().1;
5018        let mut diff_base_anchor = None;
5019        if let Some(DiffTransform::DeletedHunk {
5020            buffer_id,
5021            base_text_byte_range,
5022            has_trailing_newline,
5023            ..
5024        }) = diff_transforms.item()
5025        {
5026            let diff = self.diffs.get(buffer_id).expect("missing diff");
5027            if offset_in_transform > base_text_byte_range.len() {
5028                debug_assert!(*has_trailing_newline);
5029                bias = Bias::Right;
5030            } else {
5031                diff_base_anchor = Some(
5032                    diff.base_text()
5033                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5034                );
5035                bias = Bias::Left;
5036            }
5037        } else {
5038            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5039        };
5040
5041        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5042            return Anchor {
5043                buffer_id: Some(buffer_id),
5044                excerpt_id: *excerpt_id,
5045                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5046                diff_base_anchor,
5047            };
5048        }
5049
5050        let mut excerpts = self
5051            .excerpts
5052            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5053        excerpts.seek(&excerpt_offset, Bias::Right, &());
5054        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5055            excerpts.prev(&());
5056        }
5057        if let Some(excerpt) = excerpts.item() {
5058            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5059            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5060                overshoot -= 1;
5061                bias = Bias::Right;
5062            }
5063
5064            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5065            let text_anchor =
5066                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5067            Anchor {
5068                buffer_id: Some(excerpt.buffer_id),
5069                excerpt_id: excerpt.id,
5070                text_anchor,
5071                diff_base_anchor,
5072            }
5073        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5074            Anchor::min()
5075        } else {
5076            Anchor::max()
5077        }
5078    }
5079
5080    /// Returns an anchor for the given excerpt and text anchor,
5081    /// returns None if the excerpt_id is no longer valid.
5082    pub fn anchor_in_excerpt(
5083        &self,
5084        excerpt_id: ExcerptId,
5085        text_anchor: text::Anchor,
5086    ) -> Option<Anchor> {
5087        let locator = self.excerpt_locator_for_id(excerpt_id);
5088        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5089        cursor.seek(locator, Bias::Left, &());
5090        if let Some(excerpt) = cursor.item() {
5091            if excerpt.id == excerpt_id {
5092                let text_anchor = excerpt.clip_anchor(text_anchor);
5093                drop(cursor);
5094                return Some(Anchor {
5095                    buffer_id: Some(excerpt.buffer_id),
5096                    excerpt_id,
5097                    text_anchor,
5098                    diff_base_anchor: None,
5099                });
5100            }
5101        }
5102        None
5103    }
5104
5105    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5106        Some(self.excerpt(excerpt_id)?.range.context.clone())
5107    }
5108
5109    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5110        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5111            true
5112        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5113            excerpt.buffer.can_resolve(&anchor.text_anchor)
5114        } else {
5115            false
5116        }
5117    }
5118
5119    pub fn excerpts(
5120        &self,
5121    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5122        self.excerpts
5123            .iter()
5124            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5125    }
5126
5127    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
5128        let excerpts = self.excerpts.cursor(&());
5129        let diff_transforms = self.diff_transforms.cursor(&());
5130        MultiBufferCursor {
5131            excerpts,
5132            diff_transforms,
5133            diffs: &self.diffs,
5134            cached_region: None,
5135        }
5136    }
5137
5138    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5139        let start_locator = self.excerpt_locator_for_id(id);
5140        let mut excerpts = self
5141            .excerpts
5142            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5143        excerpts.seek(&Some(start_locator), Bias::Left, &());
5144        excerpts.prev(&());
5145
5146        let mut diff_transforms = self
5147            .diff_transforms
5148            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5149        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5150        if diff_transforms.end(&()).1 < excerpts.start().1 {
5151            diff_transforms.next(&());
5152        }
5153
5154        let excerpt = excerpts.item()?;
5155        Some(MultiBufferExcerpt {
5156            excerpt,
5157            offset: diff_transforms.start().0 .0,
5158            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5159            excerpt_offset: excerpts.start().1.clone(),
5160            diff_transforms,
5161        })
5162    }
5163
5164    pub fn excerpt_boundaries_in_range<R, T>(
5165        &self,
5166        range: R,
5167    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5168    where
5169        R: RangeBounds<T>,
5170        T: ToOffset,
5171    {
5172        let start_offset;
5173        let start = match range.start_bound() {
5174            Bound::Included(start) => {
5175                start_offset = start.to_offset(self);
5176                Bound::Included(start_offset)
5177            }
5178            Bound::Excluded(_) => {
5179                panic!("not supported")
5180            }
5181            Bound::Unbounded => {
5182                start_offset = 0;
5183                Bound::Unbounded
5184            }
5185        };
5186        let end = match range.end_bound() {
5187            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5188            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5189            Bound::Unbounded => Bound::Unbounded,
5190        };
5191        let bounds = (start, end);
5192
5193        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5194        cursor.seek(&DimensionPair {
5195            key: start_offset,
5196            value: None,
5197        });
5198
5199        if cursor
5200            .region()
5201            .is_some_and(|region| bounds.contains(&region.range.start.key))
5202        {
5203            cursor.prev_excerpt();
5204        } else {
5205            cursor.seek_to_start_of_current_excerpt();
5206        }
5207        let mut prev_region = cursor.region();
5208
5209        cursor.next_excerpt();
5210
5211        iter::from_fn(move || loop {
5212            if self.singleton {
5213                return None;
5214            }
5215
5216            let next_region = cursor.region()?;
5217            cursor.next_excerpt();
5218            if !bounds.contains(&next_region.range.start.key) {
5219                prev_region = Some(next_region);
5220                continue;
5221            }
5222
5223            let next_region_start = next_region.range.start.value.unwrap();
5224            let next_region_end = if let Some(region) = cursor.region() {
5225                region.range.start.value.unwrap()
5226            } else {
5227                self.max_point()
5228            };
5229
5230            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5231                id: region.excerpt.id,
5232                buffer: region.excerpt.buffer.clone(),
5233                buffer_id: region.excerpt.buffer_id,
5234                range: region.excerpt.range.clone(),
5235                end_row: MultiBufferRow(next_region_start.row),
5236            });
5237
5238            let next = ExcerptInfo {
5239                id: next_region.excerpt.id,
5240                buffer: next_region.excerpt.buffer.clone(),
5241                buffer_id: next_region.excerpt.buffer_id,
5242                range: next_region.excerpt.range.clone(),
5243                end_row: if next_region.excerpt.has_trailing_newline {
5244                    MultiBufferRow(next_region_end.row - 1)
5245                } else {
5246                    MultiBufferRow(next_region_end.row)
5247                },
5248            };
5249
5250            let row = MultiBufferRow(next_region_start.row);
5251
5252            prev_region = Some(next_region);
5253
5254            return Some(ExcerptBoundary { row, prev, next });
5255        })
5256    }
5257
5258    pub fn edit_count(&self) -> usize {
5259        self.edit_count
5260    }
5261
5262    pub fn non_text_state_update_count(&self) -> usize {
5263        self.non_text_state_update_count
5264    }
5265
5266    /// Returns the smallest enclosing bracket ranges containing the given range or
5267    /// None if no brackets contain range or the range is not contained in a single
5268    /// excerpt
5269    ///
5270    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5271    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5272        &self,
5273        range: Range<T>,
5274        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5275    ) -> Option<(Range<usize>, Range<usize>)> {
5276        let range = range.start.to_offset(self)..range.end.to_offset(self);
5277        let mut excerpt = self.excerpt_containing(range.clone())?;
5278        let buffer = excerpt.buffer();
5279        let excerpt_buffer_range = excerpt.buffer_range();
5280
5281        // Filter to ranges contained in the excerpt
5282        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5283            excerpt_buffer_range.contains(&open.start)
5284                && excerpt_buffer_range.contains(&close.end)
5285                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5286        };
5287
5288        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5289            excerpt.map_range_to_buffer(range),
5290            Some(&range_filter),
5291        )?;
5292
5293        Some((
5294            excerpt.map_range_from_buffer(open),
5295            excerpt.map_range_from_buffer(close),
5296        ))
5297    }
5298
5299    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5300    /// not contained in a single excerpt
5301    pub fn enclosing_bracket_ranges<T: ToOffset>(
5302        &self,
5303        range: Range<T>,
5304    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5305        let range = range.start.to_offset(self)..range.end.to_offset(self);
5306        let mut excerpt = self.excerpt_containing(range.clone())?;
5307
5308        Some(
5309            excerpt
5310                .buffer()
5311                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5312                .filter_map(move |pair| {
5313                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5314                        Some((
5315                            excerpt.map_range_from_buffer(pair.open_range),
5316                            excerpt.map_range_from_buffer(pair.close_range),
5317                        ))
5318                    } else {
5319                        None
5320                    }
5321                }),
5322        )
5323    }
5324
5325    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5326    /// not contained in a single excerpt
5327    pub fn text_object_ranges<T: ToOffset>(
5328        &self,
5329        range: Range<T>,
5330        options: TreeSitterOptions,
5331    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5332        let range = range.start.to_offset(self)..range.end.to_offset(self);
5333        self.excerpt_containing(range.clone())
5334            .map(|mut excerpt| {
5335                excerpt
5336                    .buffer()
5337                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5338                    .filter_map(move |(range, text_object)| {
5339                        if excerpt.contains_buffer_range(range.clone()) {
5340                            Some((excerpt.map_range_from_buffer(range), text_object))
5341                        } else {
5342                            None
5343                        }
5344                    })
5345            })
5346            .into_iter()
5347            .flatten()
5348    }
5349
5350    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5351    /// not contained in a single excerpt
5352    pub fn bracket_ranges<T: ToOffset>(
5353        &self,
5354        range: Range<T>,
5355    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5356        let range = range.start.to_offset(self)..range.end.to_offset(self);
5357        let mut excerpt = self.excerpt_containing(range.clone())?;
5358
5359        Some(
5360            excerpt
5361                .buffer()
5362                .bracket_ranges(excerpt.map_range_to_buffer(range))
5363                .filter_map(move |pair| {
5364                    let buffer_range = pair.open_range.start..pair.close_range.end;
5365                    if excerpt.contains_buffer_range(buffer_range) {
5366                        Some((
5367                            excerpt.map_range_from_buffer(pair.open_range),
5368                            excerpt.map_range_from_buffer(pair.close_range),
5369                        ))
5370                    } else {
5371                        None
5372                    }
5373                }),
5374        )
5375    }
5376
5377    pub fn redacted_ranges<'a, T: ToOffset>(
5378        &'a self,
5379        range: Range<T>,
5380        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5381    ) -> impl Iterator<Item = Range<usize>> + 'a {
5382        let range = range.start.to_offset(self)..range.end.to_offset(self);
5383        self.lift_buffer_metadata(range, move |buffer, range| {
5384            if redaction_enabled(buffer.file()) {
5385                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5386            } else {
5387                None
5388            }
5389        })
5390        .map(|(range, _, _)| range)
5391    }
5392
5393    pub fn runnable_ranges(
5394        &self,
5395        range: Range<Anchor>,
5396    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5397        let range = range.start.to_offset(self)..range.end.to_offset(self);
5398        self.lift_buffer_metadata(range, move |buffer, range| {
5399            Some(
5400                buffer
5401                    .runnable_ranges(range.clone())
5402                    .filter(move |runnable| {
5403                        runnable.run_range.start >= range.start
5404                            && runnable.run_range.end < range.end
5405                    })
5406                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5407            )
5408        })
5409        .map(|(run_range, runnable, _)| language::RunnableRange {
5410            run_range,
5411            ..runnable
5412        })
5413    }
5414
5415    pub fn line_indents(
5416        &self,
5417        start_row: MultiBufferRow,
5418        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5419    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5420        let max_point = self.max_point();
5421        let mut cursor = self.cursor::<Point>();
5422        cursor.seek(&Point::new(start_row.0, 0));
5423        iter::from_fn(move || {
5424            let mut region = cursor.region()?;
5425            while !buffer_filter(&region.excerpt.buffer) {
5426                cursor.next();
5427                region = cursor.region()?;
5428            }
5429            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5430            let buffer_start_row =
5431                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5432
5433            let buffer_end_row = if region.is_main_buffer
5434                && (region.has_trailing_newline || region.range.end == max_point)
5435            {
5436                region.buffer_range.end.row
5437            } else {
5438                region.buffer_range.end.row.saturating_sub(1)
5439            };
5440
5441            let line_indents = region
5442                .buffer
5443                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5444            cursor.next();
5445            return Some(line_indents.map(move |(buffer_row, indent)| {
5446                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5447                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5448            }));
5449        })
5450        .flatten()
5451    }
5452
5453    pub fn reversed_line_indents(
5454        &self,
5455        end_row: MultiBufferRow,
5456        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5457    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5458        let max_point = self.max_point();
5459        let mut cursor = self.cursor::<Point>();
5460        cursor.seek(&Point::new(end_row.0, 0));
5461        iter::from_fn(move || {
5462            let mut region = cursor.region()?;
5463            while !buffer_filter(&region.excerpt.buffer) {
5464                cursor.prev();
5465                region = cursor.region()?;
5466            }
5467
5468            let buffer_start_row = region.buffer_range.start.row;
5469            let buffer_end_row = if region.is_main_buffer
5470                && (region.has_trailing_newline || region.range.end == max_point)
5471            {
5472                region.buffer_range.end.row + 1
5473            } else {
5474                region.buffer_range.end.row
5475            };
5476
5477            let overshoot = end_row.0 - region.range.start.row;
5478            let buffer_end_row =
5479                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5480
5481            let line_indents = region
5482                .buffer
5483                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5484            cursor.prev();
5485            return Some(line_indents.map(move |(buffer_row, indent)| {
5486                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5487                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5488            }));
5489        })
5490        .flatten()
5491    }
5492
5493    pub async fn enclosing_indent(
5494        &self,
5495        mut target_row: MultiBufferRow,
5496    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5497        let max_row = MultiBufferRow(self.max_point().row);
5498        if target_row >= max_row {
5499            return None;
5500        }
5501
5502        let mut target_indent = self.line_indent_for_row(target_row);
5503
5504        // If the current row is at the start of an indented block, we want to return this
5505        // block as the enclosing indent.
5506        if !target_indent.is_line_empty() && target_row < max_row {
5507            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5508            if !next_line_indent.is_line_empty()
5509                && target_indent.raw_len() < next_line_indent.raw_len()
5510            {
5511                target_indent = next_line_indent;
5512                target_row.0 += 1;
5513            }
5514        }
5515
5516        const SEARCH_ROW_LIMIT: u32 = 25000;
5517        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5518        const YIELD_INTERVAL: u32 = 100;
5519
5520        let mut accessed_row_counter = 0;
5521
5522        // If there is a blank line at the current row, search for the next non indented lines
5523        if target_indent.is_line_empty() {
5524            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5525            let end =
5526                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5527
5528            let mut non_empty_line_above = None;
5529            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5530                if row < start {
5531                    break;
5532                }
5533                accessed_row_counter += 1;
5534                if accessed_row_counter == YIELD_INTERVAL {
5535                    accessed_row_counter = 0;
5536                    yield_now().await;
5537                }
5538                if !indent.is_line_empty() {
5539                    non_empty_line_above = Some((row, indent));
5540                    break;
5541                }
5542            }
5543
5544            let mut non_empty_line_below = None;
5545            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5546                if row > end {
5547                    break;
5548                }
5549                accessed_row_counter += 1;
5550                if accessed_row_counter == YIELD_INTERVAL {
5551                    accessed_row_counter = 0;
5552                    yield_now().await;
5553                }
5554                if !indent.is_line_empty() {
5555                    non_empty_line_below = Some((row, indent));
5556                    break;
5557                }
5558            }
5559
5560            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5561                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5562                    if above_indent.raw_len() >= below_indent.raw_len() {
5563                        (above_row, above_indent)
5564                    } else {
5565                        (below_row, below_indent)
5566                    }
5567                }
5568                (Some(above), None) => above,
5569                (None, Some(below)) => below,
5570                _ => return None,
5571            };
5572
5573            target_indent = indent;
5574            target_row = row;
5575        }
5576
5577        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5578        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5579
5580        let mut start_indent = None;
5581        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5582            if row < start {
5583                break;
5584            }
5585            accessed_row_counter += 1;
5586            if accessed_row_counter == YIELD_INTERVAL {
5587                accessed_row_counter = 0;
5588                yield_now().await;
5589            }
5590            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5591                start_indent = Some((row, indent));
5592                break;
5593            }
5594        }
5595        let (start_row, start_indent_size) = start_indent?;
5596
5597        let mut end_indent = (end, None);
5598        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5599            if row > end {
5600                break;
5601            }
5602            accessed_row_counter += 1;
5603            if accessed_row_counter == YIELD_INTERVAL {
5604                accessed_row_counter = 0;
5605                yield_now().await;
5606            }
5607            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5608                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5609                break;
5610            }
5611        }
5612        let (end_row, end_indent_size) = end_indent;
5613
5614        let indent = if let Some(end_indent_size) = end_indent_size {
5615            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5616                start_indent_size
5617            } else {
5618                end_indent_size
5619            }
5620        } else {
5621            start_indent_size
5622        };
5623
5624        Some((start_row..end_row, indent))
5625    }
5626
5627    pub fn indent_guides_in_range<T: ToPoint>(
5628        &self,
5629        range: Range<T>,
5630        ignore_disabled_for_language: bool,
5631        cx: &App,
5632    ) -> impl Iterator<Item = IndentGuide> {
5633        let range = range.start.to_point(self)..range.end.to_point(self);
5634        let start_row = MultiBufferRow(range.start.row);
5635        let end_row = MultiBufferRow(range.end.row);
5636
5637        let mut row_indents = self.line_indents(start_row, |buffer| {
5638            let settings =
5639                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5640            settings.indent_guides.enabled || ignore_disabled_for_language
5641        });
5642
5643        let mut result = Vec::new();
5644        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5645
5646        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5647            if first_row > end_row {
5648                break;
5649            }
5650            let current_depth = indent_stack.len() as u32;
5651
5652            let settings =
5653                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5654            let tab_size = settings.tab_size.get() as u32;
5655
5656            // When encountering empty, continue until found useful line indent
5657            // then add to the indent stack with the depth found
5658            let mut found_indent = false;
5659            let mut last_row = first_row;
5660            if line_indent.is_line_empty() {
5661                while !found_indent {
5662                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5663                        break;
5664                    };
5665                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5666                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5667                        break;
5668                    }
5669
5670                    if new_line_indent.is_line_empty() {
5671                        continue;
5672                    }
5673                    last_row = target_row.min(end_row);
5674                    line_indent = new_line_indent;
5675                    found_indent = true;
5676                    break;
5677                }
5678            } else {
5679                found_indent = true
5680            }
5681
5682            let depth = if found_indent {
5683                line_indent.len(tab_size) / tab_size
5684                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5685            } else {
5686                current_depth
5687            };
5688
5689            match depth.cmp(&current_depth) {
5690                cmp::Ordering::Less => {
5691                    for _ in 0..(current_depth - depth) {
5692                        let mut indent = indent_stack.pop().unwrap();
5693                        if last_row != first_row {
5694                            // In this case, we landed on an empty row, had to seek forward,
5695                            // and discovered that the indent we where on is ending.
5696                            // This means that the last display row must
5697                            // be on line that ends this indent range, so we
5698                            // should display the range up to the first non-empty line
5699                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5700                        }
5701
5702                        result.push(indent)
5703                    }
5704                }
5705                cmp::Ordering::Greater => {
5706                    for next_depth in current_depth..depth {
5707                        indent_stack.push(IndentGuide {
5708                            buffer_id: buffer.remote_id(),
5709                            start_row: first_row,
5710                            end_row: last_row,
5711                            depth: next_depth,
5712                            tab_size,
5713                            settings: settings.indent_guides,
5714                        });
5715                    }
5716                }
5717                _ => {}
5718            }
5719
5720            for indent in indent_stack.iter_mut() {
5721                indent.end_row = last_row;
5722            }
5723        }
5724
5725        result.extend(indent_stack);
5726        result.into_iter()
5727    }
5728
5729    pub fn trailing_excerpt_update_count(&self) -> usize {
5730        self.trailing_excerpt_update_count
5731    }
5732
5733    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5734        self.point_to_buffer_offset(point)
5735            .and_then(|(buffer, _)| buffer.file())
5736    }
5737
5738    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5739        self.point_to_buffer_offset(point)
5740            .and_then(|(buffer, offset)| buffer.language_at(offset))
5741    }
5742
5743    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5744        self.excerpts
5745            .first()
5746            .map(|excerpt| &excerpt.buffer)
5747            .map(|buffer| {
5748                language_settings(
5749                    buffer.language().map(|language| language.name()),
5750                    buffer.file(),
5751                    cx,
5752                )
5753            })
5754            .unwrap_or_else(move || self.language_settings_at(0, cx))
5755    }
5756
5757    pub fn language_settings_at<'a, T: ToOffset>(
5758        &'a self,
5759        point: T,
5760        cx: &'a App,
5761    ) -> Cow<'a, LanguageSettings> {
5762        let mut language = None;
5763        let mut file = None;
5764        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5765            language = buffer.language_at(offset);
5766            file = buffer.file();
5767        }
5768        language_settings(language.map(|l| l.name()), file, cx)
5769    }
5770
5771    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5772        self.point_to_buffer_offset(point)
5773            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5774    }
5775
5776    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5777        self.point_to_buffer_offset(point)
5778            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5779            .unwrap_or_default()
5780    }
5781
5782    pub fn language_indent_size_at<T: ToOffset>(
5783        &self,
5784        position: T,
5785        cx: &App,
5786    ) -> Option<IndentSize> {
5787        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5788        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5789    }
5790
5791    pub fn is_dirty(&self) -> bool {
5792        self.is_dirty
5793    }
5794
5795    pub fn has_deleted_file(&self) -> bool {
5796        self.has_deleted_file
5797    }
5798
5799    pub fn has_conflict(&self) -> bool {
5800        self.has_conflict
5801    }
5802
5803    pub fn has_diagnostics(&self) -> bool {
5804        self.excerpts
5805            .iter()
5806            .any(|excerpt| excerpt.buffer.has_diagnostics())
5807    }
5808
5809    pub fn diagnostic_group(
5810        &self,
5811        buffer_id: BufferId,
5812        group_id: usize,
5813    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5814        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5815            if buffer.remote_id() != buffer_id {
5816                return None;
5817            };
5818            Some(
5819                buffer
5820                    .diagnostic_group(group_id)
5821                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5822            )
5823        })
5824        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5825    }
5826
5827    pub fn diagnostics_in_range<'a, T>(
5828        &'a self,
5829        range: Range<T>,
5830    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5831    where
5832        T: 'a
5833            + text::ToOffset
5834            + text::FromAnchor
5835            + TextDimension
5836            + Ord
5837            + Sub<T, Output = T>
5838            + fmt::Debug,
5839    {
5840        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5841            Some(
5842                buffer
5843                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5844                    .map(|entry| (entry.range, entry.diagnostic)),
5845            )
5846        })
5847        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5848    }
5849
5850    pub fn syntax_ancestor<T: ToOffset>(
5851        &self,
5852        range: Range<T>,
5853    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5854        let range = range.start.to_offset(self)..range.end.to_offset(self);
5855        let mut excerpt = self.excerpt_containing(range.clone())?;
5856        let node = excerpt
5857            .buffer()
5858            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5859        let node_range = node.byte_range();
5860        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5861            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5862        } else {
5863            MultiOrSingleBufferOffsetRange::Single(node_range)
5864        };
5865        Some((node, range))
5866    }
5867
5868    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5869        let (excerpt_id, _, buffer) = self.as_singleton()?;
5870        let outline = buffer.outline(theme)?;
5871        Some(Outline::new(
5872            outline
5873                .items
5874                .into_iter()
5875                .flat_map(|item| {
5876                    Some(OutlineItem {
5877                        depth: item.depth,
5878                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5879                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5880                        text: item.text,
5881                        highlight_ranges: item.highlight_ranges,
5882                        name_ranges: item.name_ranges,
5883                        body_range: item.body_range.and_then(|body_range| {
5884                            Some(
5885                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5886                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5887                            )
5888                        }),
5889                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5890                            Some(
5891                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5892                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5893                            )
5894                        }),
5895                    })
5896                })
5897                .collect(),
5898        ))
5899    }
5900
5901    pub fn symbols_containing<T: ToOffset>(
5902        &self,
5903        offset: T,
5904        theme: Option<&SyntaxTheme>,
5905    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5906        let anchor = self.anchor_before(offset);
5907        let excerpt_id = anchor.excerpt_id;
5908        let excerpt = self.excerpt(excerpt_id)?;
5909        Some((
5910            excerpt.buffer_id,
5911            excerpt
5912                .buffer
5913                .symbols_containing(anchor.text_anchor, theme)
5914                .into_iter()
5915                .flatten()
5916                .flat_map(|item| {
5917                    Some(OutlineItem {
5918                        depth: item.depth,
5919                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5920                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5921                        text: item.text,
5922                        highlight_ranges: item.highlight_ranges,
5923                        name_ranges: item.name_ranges,
5924                        body_range: item.body_range.and_then(|body_range| {
5925                            Some(
5926                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5927                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5928                            )
5929                        }),
5930                        annotation_range: item.annotation_range.and_then(|body_range| {
5931                            Some(
5932                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5933                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5934                            )
5935                        }),
5936                    })
5937                })
5938                .collect(),
5939        ))
5940    }
5941
5942    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5943        if id == ExcerptId::min() {
5944            Locator::min_ref()
5945        } else if id == ExcerptId::max() {
5946            Locator::max_ref()
5947        } else {
5948            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5949            cursor.seek(&id, Bias::Left, &());
5950            if let Some(entry) = cursor.item() {
5951                if entry.id == id {
5952                    return &entry.locator;
5953                }
5954            }
5955            panic!("invalid excerpt id {:?}", id)
5956        }
5957    }
5958
5959    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5960    fn excerpt_locators_for_ids(
5961        &self,
5962        ids: impl IntoIterator<Item = ExcerptId>,
5963    ) -> SmallVec<[Locator; 1]> {
5964        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5965        sorted_ids.sort_unstable();
5966        let mut locators = SmallVec::new();
5967
5968        while sorted_ids.last() == Some(&ExcerptId::max()) {
5969            sorted_ids.pop();
5970            if let Some(mapping) = self.excerpt_ids.last() {
5971                locators.push(mapping.locator.clone());
5972            }
5973        }
5974
5975        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5976        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5977            sorted_ids.next();
5978            if let Some(mapping) = self.excerpt_ids.first() {
5979                locators.push(mapping.locator.clone());
5980            }
5981        }
5982
5983        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5984        for id in sorted_ids {
5985            if cursor.seek_forward(&id, Bias::Left, &()) {
5986                locators.push(cursor.item().unwrap().locator.clone());
5987            } else {
5988                panic!("invalid excerpt id {:?}", id);
5989            }
5990        }
5991
5992        locators.sort_unstable();
5993        locators
5994    }
5995
5996    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5997        Some(self.excerpt(excerpt_id)?.buffer_id)
5998    }
5999
6000    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6001        Some(&self.excerpt(excerpt_id)?.buffer)
6002    }
6003
6004    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6005        let mut cursor = self
6006            .excerpts
6007            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6008        let locator = self.excerpt_locator_for_id(excerpt_id);
6009        if cursor.seek(&Some(locator), Bias::Left, &()) {
6010            let start = cursor.start().1.clone();
6011            let end = cursor.end(&()).1;
6012            let mut diff_transforms = self
6013                .diff_transforms
6014                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6015            diff_transforms.seek(&start, Bias::Left, &());
6016            let overshoot = start.0 - diff_transforms.start().0 .0;
6017            let start = diff_transforms.start().1 .0 + overshoot;
6018            diff_transforms.seek(&end, Bias::Right, &());
6019            let overshoot = end.0 - diff_transforms.start().0 .0;
6020            let end = diff_transforms.start().1 .0 + overshoot;
6021            Some(start..end)
6022        } else {
6023            None
6024        }
6025    }
6026
6027    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6028        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6029        let locator = self.excerpt_locator_for_id(excerpt_id);
6030        if cursor.seek(&Some(locator), Bias::Left, &()) {
6031            if let Some(excerpt) = cursor.item() {
6032                return Some(excerpt.range.context.clone());
6033            }
6034        }
6035        None
6036    }
6037
6038    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6039        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6040        let locator = self.excerpt_locator_for_id(excerpt_id);
6041        cursor.seek(&Some(locator), Bias::Left, &());
6042        if let Some(excerpt) = cursor.item() {
6043            if excerpt.id == excerpt_id {
6044                return Some(excerpt);
6045            }
6046        }
6047        None
6048    }
6049
6050    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6051    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
6052        let range = range.start.to_offset(self)..range.end.to_offset(self);
6053        let mut cursor = self.cursor::<usize>();
6054        cursor.seek(&range.start);
6055
6056        let start_excerpt = cursor.excerpt()?;
6057        if range.end != range.start {
6058            cursor.seek_forward(&range.end);
6059            if cursor.excerpt()?.id != start_excerpt.id {
6060                return None;
6061            }
6062        }
6063
6064        cursor.seek_to_start_of_current_excerpt();
6065        let region = cursor.region()?;
6066        let offset = region.range.start;
6067        let buffer_offset = region.buffer_range.start;
6068        let excerpt_offset = cursor.excerpts.start().clone();
6069        Some(MultiBufferExcerpt {
6070            diff_transforms: cursor.diff_transforms,
6071            excerpt: start_excerpt,
6072            offset,
6073            buffer_offset,
6074            excerpt_offset,
6075        })
6076    }
6077
6078    pub fn selections_in_range<'a>(
6079        &'a self,
6080        range: &'a Range<Anchor>,
6081        include_local: bool,
6082    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6083        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6084        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6085        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6086        cursor.seek(start_locator, Bias::Left, &());
6087        cursor
6088            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6089            .flat_map(move |excerpt| {
6090                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6091                if excerpt.id == range.start.excerpt_id {
6092                    query_range.start = range.start.text_anchor;
6093                }
6094                if excerpt.id == range.end.excerpt_id {
6095                    query_range.end = range.end.text_anchor;
6096                }
6097
6098                excerpt
6099                    .buffer
6100                    .selections_in_range(query_range, include_local)
6101                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6102                        selections.map(move |selection| {
6103                            let mut start = Anchor {
6104                                buffer_id: Some(excerpt.buffer_id),
6105                                excerpt_id: excerpt.id,
6106                                text_anchor: selection.start,
6107                                diff_base_anchor: None,
6108                            };
6109                            let mut end = Anchor {
6110                                buffer_id: Some(excerpt.buffer_id),
6111                                excerpt_id: excerpt.id,
6112                                text_anchor: selection.end,
6113                                diff_base_anchor: None,
6114                            };
6115                            if range.start.cmp(&start, self).is_gt() {
6116                                start = range.start;
6117                            }
6118                            if range.end.cmp(&end, self).is_lt() {
6119                                end = range.end;
6120                            }
6121
6122                            (
6123                                replica_id,
6124                                line_mode,
6125                                cursor_shape,
6126                                Selection {
6127                                    id: selection.id,
6128                                    start,
6129                                    end,
6130                                    reversed: selection.reversed,
6131                                    goal: selection.goal,
6132                                },
6133                            )
6134                        })
6135                    })
6136            })
6137    }
6138
6139    pub fn show_headers(&self) -> bool {
6140        self.show_headers
6141    }
6142
6143    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6144        self.diffs.get(&buffer_id)
6145    }
6146}
6147
6148#[cfg(any(test, feature = "test-support"))]
6149impl MultiBufferSnapshot {
6150    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6151        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6152        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6153        start..end
6154    }
6155
6156    #[cfg(any(test, feature = "test-support"))]
6157    fn check_invariants(&self) {
6158        let excerpts = self.excerpts.items(&());
6159        let excerpt_ids = self.excerpt_ids.items(&());
6160
6161        for (ix, excerpt) in excerpts.iter().enumerate() {
6162            if ix == 0 {
6163                if excerpt.locator <= Locator::min() {
6164                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6165                }
6166            } else if excerpt.locator <= excerpts[ix - 1].locator {
6167                panic!("excerpts are out-of-order: {:?}", excerpts);
6168            }
6169        }
6170
6171        for (ix, entry) in excerpt_ids.iter().enumerate() {
6172            if ix == 0 {
6173                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6174                    panic!("invalid first excerpt id {:?}", entry.id);
6175                }
6176            } else if entry.id <= excerpt_ids[ix - 1].id {
6177                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6178            }
6179        }
6180
6181        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6182            panic!(
6183                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6184                self.excerpts.summary().text.len,
6185                self.diff_transforms.summary().input,
6186                self.diff_transforms.items(&()),
6187            );
6188        }
6189
6190        let mut prev_transform: Option<&DiffTransform> = None;
6191        for item in self.diff_transforms.iter() {
6192            if let DiffTransform::BufferContent {
6193                summary,
6194                inserted_hunk_info,
6195            } = item
6196            {
6197                if let Some(DiffTransform::BufferContent {
6198                    inserted_hunk_info: prev_inserted_hunk_info,
6199                    ..
6200                }) = prev_transform
6201                {
6202                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6203                        panic!(
6204                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6205                            self.diff_transforms.items(&()));
6206                    }
6207                }
6208                if summary.len == 0 && !self.is_empty() {
6209                    panic!("empty buffer content transform");
6210                }
6211            }
6212            prev_transform = Some(item);
6213        }
6214    }
6215}
6216
6217impl<'a, D> MultiBufferCursor<'a, D>
6218where
6219    D: TextDimension + Ord + Sub<D, Output = D>,
6220{
6221    fn seek(&mut self, position: &D) {
6222        self.cached_region.take();
6223        self.diff_transforms
6224            .seek(&OutputDimension(*position), Bias::Right, &());
6225        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6226            self.diff_transforms.prev(&());
6227        }
6228
6229        let mut excerpt_position = self.diff_transforms.start().1 .0;
6230        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6231            let overshoot = *position - self.diff_transforms.start().0 .0;
6232            excerpt_position.add_assign(&overshoot);
6233        }
6234
6235        self.excerpts
6236            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6237        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6238            self.excerpts.prev(&());
6239        }
6240    }
6241
6242    fn seek_forward(&mut self, position: &D) {
6243        self.cached_region.take();
6244        self.diff_transforms
6245            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6246        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6247            self.diff_transforms.prev(&());
6248        }
6249
6250        let overshoot = *position - self.diff_transforms.start().0 .0;
6251        let mut excerpt_position = self.diff_transforms.start().1 .0;
6252        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6253            excerpt_position.add_assign(&overshoot);
6254        }
6255
6256        self.excerpts
6257            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6258        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6259            self.excerpts.prev(&());
6260        }
6261    }
6262
6263    fn next_excerpt(&mut self) {
6264        self.excerpts.next(&());
6265        self.seek_to_start_of_current_excerpt();
6266    }
6267
6268    fn prev_excerpt(&mut self) {
6269        self.excerpts.prev(&());
6270        self.seek_to_start_of_current_excerpt();
6271    }
6272
6273    fn seek_to_start_of_current_excerpt(&mut self) {
6274        self.cached_region.take();
6275        self.diff_transforms
6276            .seek(self.excerpts.start(), Bias::Left, &());
6277        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6278            && self.diff_transforms.start().1 < *self.excerpts.start()
6279            && self.diff_transforms.next_item().is_some()
6280        {
6281            self.diff_transforms.next(&());
6282        }
6283    }
6284
6285    fn next(&mut self) {
6286        self.cached_region.take();
6287        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6288            cmp::Ordering::Less => self.diff_transforms.next(&()),
6289            cmp::Ordering::Greater => self.excerpts.next(&()),
6290            cmp::Ordering::Equal => {
6291                self.diff_transforms.next(&());
6292                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6293                    || self.diff_transforms.item().is_none()
6294                {
6295                    self.excerpts.next(&());
6296                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6297                    self.diff_transforms.item()
6298                {
6299                    if self
6300                        .excerpts
6301                        .item()
6302                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6303                    {
6304                        self.excerpts.next(&());
6305                    }
6306                }
6307            }
6308        }
6309    }
6310
6311    fn prev(&mut self) {
6312        self.cached_region.take();
6313        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6314            cmp::Ordering::Less => self.excerpts.prev(&()),
6315            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6316            cmp::Ordering::Equal => {
6317                self.diff_transforms.prev(&());
6318                if self.diff_transforms.start().1 < *self.excerpts.start()
6319                    || self.diff_transforms.item().is_none()
6320                {
6321                    self.excerpts.prev(&());
6322                }
6323            }
6324        }
6325    }
6326
6327    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6328        if self.cached_region.is_none() {
6329            self.cached_region = self.build_region();
6330        }
6331        self.cached_region.clone()
6332    }
6333
6334    fn is_at_start_of_excerpt(&mut self) -> bool {
6335        if self.diff_transforms.start().1 > *self.excerpts.start() {
6336            return false;
6337        } else if self.diff_transforms.start().1 < *self.excerpts.start() {
6338            return true;
6339        }
6340
6341        self.diff_transforms.prev(&());
6342        let prev_transform = self.diff_transforms.item();
6343        self.diff_transforms.next(&());
6344
6345        prev_transform.map_or(true, |next_transform| {
6346            matches!(next_transform, DiffTransform::BufferContent { .. })
6347        })
6348    }
6349
6350    fn is_at_end_of_excerpt(&mut self) -> bool {
6351        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6352            return false;
6353        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6354            || self.diff_transforms.item().is_none()
6355        {
6356            return true;
6357        }
6358
6359        let next_transform = self.diff_transforms.next_item();
6360        next_transform.map_or(true, |next_transform| match next_transform {
6361            DiffTransform::BufferContent { .. } => true,
6362            DiffTransform::DeletedHunk { hunk_info, .. } => self
6363                .excerpts
6364                .item()
6365                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6366        })
6367    }
6368
6369    fn main_buffer_position(&self) -> Option<D> {
6370        let excerpt = self.excerpts.item()?;
6371        let buffer = &excerpt.buffer;
6372        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6373        let mut buffer_start = buffer_context_start;
6374        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6375        buffer_start.add_assign(&overshoot);
6376        Some(buffer_start)
6377    }
6378
6379    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6380        let excerpt = self.excerpts.item()?;
6381        match self.diff_transforms.item()? {
6382            DiffTransform::DeletedHunk {
6383                buffer_id,
6384                base_text_byte_range,
6385                has_trailing_newline,
6386                hunk_info,
6387                ..
6388            } => {
6389                let diff = self.diffs.get(&buffer_id)?;
6390                let buffer = diff.base_text();
6391                let mut rope_cursor = buffer.as_rope().cursor(0);
6392                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6393                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6394                let mut buffer_end = buffer_start;
6395                buffer_end.add_assign(&buffer_range_len);
6396                let start = self.diff_transforms.start().0 .0;
6397                let end = self.diff_transforms.end(&()).0 .0;
6398                return Some(MultiBufferRegion {
6399                    buffer,
6400                    excerpt,
6401                    has_trailing_newline: *has_trailing_newline,
6402                    is_main_buffer: false,
6403                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6404                        hunk_info.hunk_secondary_status,
6405                    )),
6406                    buffer_range: buffer_start..buffer_end,
6407                    range: start..end,
6408                });
6409            }
6410            DiffTransform::BufferContent {
6411                inserted_hunk_info, ..
6412            } => {
6413                let buffer = &excerpt.buffer;
6414                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6415
6416                let mut start = self.diff_transforms.start().0 .0;
6417                let mut buffer_start = buffer_context_start;
6418                if self.diff_transforms.start().1 < *self.excerpts.start() {
6419                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6420                    start.add_assign(&overshoot);
6421                } else {
6422                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6423                    buffer_start.add_assign(&overshoot);
6424                }
6425
6426                let mut end;
6427                let mut buffer_end;
6428                let has_trailing_newline;
6429                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6430                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6431                    end = self.diff_transforms.end(&()).0 .0;
6432                    buffer_end = buffer_context_start;
6433                    buffer_end.add_assign(&overshoot);
6434                    has_trailing_newline = false;
6435                } else {
6436                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6437                    end = self.diff_transforms.start().0 .0;
6438                    end.add_assign(&overshoot);
6439                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6440                    has_trailing_newline = excerpt.has_trailing_newline;
6441                };
6442
6443                Some(MultiBufferRegion {
6444                    buffer,
6445                    excerpt,
6446                    has_trailing_newline,
6447                    is_main_buffer: true,
6448                    diff_hunk_status: inserted_hunk_info
6449                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6450                    buffer_range: buffer_start..buffer_end,
6451                    range: start..end,
6452                })
6453            }
6454        }
6455    }
6456
6457    fn excerpt(&self) -> Option<&'a Excerpt> {
6458        self.excerpts.item()
6459    }
6460}
6461
6462impl History {
6463    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6464        self.transaction_depth += 1;
6465        if self.transaction_depth == 1 {
6466            let id = self.next_transaction_id.tick();
6467            self.undo_stack.push(Transaction {
6468                id,
6469                buffer_transactions: Default::default(),
6470                first_edit_at: now,
6471                last_edit_at: now,
6472                suppress_grouping: false,
6473            });
6474            Some(id)
6475        } else {
6476            None
6477        }
6478    }
6479
6480    fn end_transaction(
6481        &mut self,
6482        now: Instant,
6483        buffer_transactions: HashMap<BufferId, TransactionId>,
6484    ) -> bool {
6485        assert_ne!(self.transaction_depth, 0);
6486        self.transaction_depth -= 1;
6487        if self.transaction_depth == 0 {
6488            if buffer_transactions.is_empty() {
6489                self.undo_stack.pop();
6490                false
6491            } else {
6492                self.redo_stack.clear();
6493                let transaction = self.undo_stack.last_mut().unwrap();
6494                transaction.last_edit_at = now;
6495                for (buffer_id, transaction_id) in buffer_transactions {
6496                    transaction
6497                        .buffer_transactions
6498                        .entry(buffer_id)
6499                        .or_insert(transaction_id);
6500                }
6501                true
6502            }
6503        } else {
6504            false
6505        }
6506    }
6507
6508    fn push_transaction<'a, T>(
6509        &mut self,
6510        buffer_transactions: T,
6511        now: Instant,
6512        cx: &Context<MultiBuffer>,
6513    ) where
6514        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6515    {
6516        assert_eq!(self.transaction_depth, 0);
6517        let transaction = Transaction {
6518            id: self.next_transaction_id.tick(),
6519            buffer_transactions: buffer_transactions
6520                .into_iter()
6521                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6522                .collect(),
6523            first_edit_at: now,
6524            last_edit_at: now,
6525            suppress_grouping: false,
6526        };
6527        if !transaction.buffer_transactions.is_empty() {
6528            self.undo_stack.push(transaction);
6529            self.redo_stack.clear();
6530        }
6531    }
6532
6533    fn finalize_last_transaction(&mut self) {
6534        if let Some(transaction) = self.undo_stack.last_mut() {
6535            transaction.suppress_grouping = true;
6536        }
6537    }
6538
6539    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6540        if let Some(ix) = self
6541            .undo_stack
6542            .iter()
6543            .rposition(|transaction| transaction.id == transaction_id)
6544        {
6545            Some(self.undo_stack.remove(ix))
6546        } else if let Some(ix) = self
6547            .redo_stack
6548            .iter()
6549            .rposition(|transaction| transaction.id == transaction_id)
6550        {
6551            Some(self.redo_stack.remove(ix))
6552        } else {
6553            None
6554        }
6555    }
6556
6557    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6558        self.undo_stack
6559            .iter()
6560            .find(|transaction| transaction.id == transaction_id)
6561            .or_else(|| {
6562                self.redo_stack
6563                    .iter()
6564                    .find(|transaction| transaction.id == transaction_id)
6565            })
6566    }
6567
6568    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6569        self.undo_stack
6570            .iter_mut()
6571            .find(|transaction| transaction.id == transaction_id)
6572            .or_else(|| {
6573                self.redo_stack
6574                    .iter_mut()
6575                    .find(|transaction| transaction.id == transaction_id)
6576            })
6577    }
6578
6579    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6580        assert_eq!(self.transaction_depth, 0);
6581        if let Some(transaction) = self.undo_stack.pop() {
6582            self.redo_stack.push(transaction);
6583            self.redo_stack.last_mut()
6584        } else {
6585            None
6586        }
6587    }
6588
6589    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6590        assert_eq!(self.transaction_depth, 0);
6591        if let Some(transaction) = self.redo_stack.pop() {
6592            self.undo_stack.push(transaction);
6593            self.undo_stack.last_mut()
6594        } else {
6595            None
6596        }
6597    }
6598
6599    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6600        let ix = self
6601            .undo_stack
6602            .iter()
6603            .rposition(|transaction| transaction.id == transaction_id)?;
6604        let transaction = self.undo_stack.remove(ix);
6605        self.redo_stack.push(transaction);
6606        self.redo_stack.last()
6607    }
6608
6609    fn group(&mut self) -> Option<TransactionId> {
6610        let mut count = 0;
6611        let mut transactions = self.undo_stack.iter();
6612        if let Some(mut transaction) = transactions.next_back() {
6613            while let Some(prev_transaction) = transactions.next_back() {
6614                if !prev_transaction.suppress_grouping
6615                    && transaction.first_edit_at - prev_transaction.last_edit_at
6616                        <= self.group_interval
6617                {
6618                    transaction = prev_transaction;
6619                    count += 1;
6620                } else {
6621                    break;
6622                }
6623            }
6624        }
6625        self.group_trailing(count)
6626    }
6627
6628    fn group_until(&mut self, transaction_id: TransactionId) {
6629        let mut count = 0;
6630        for transaction in self.undo_stack.iter().rev() {
6631            if transaction.id == transaction_id {
6632                self.group_trailing(count);
6633                break;
6634            } else if transaction.suppress_grouping {
6635                break;
6636            } else {
6637                count += 1;
6638            }
6639        }
6640    }
6641
6642    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6643        let new_len = self.undo_stack.len() - n;
6644        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6645        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6646            if let Some(transaction) = transactions_to_merge.last() {
6647                last_transaction.last_edit_at = transaction.last_edit_at;
6648            }
6649            for to_merge in transactions_to_merge {
6650                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6651                    last_transaction
6652                        .buffer_transactions
6653                        .entry(*buffer_id)
6654                        .or_insert(*transaction_id);
6655                }
6656            }
6657        }
6658
6659        self.undo_stack.truncate(new_len);
6660        self.undo_stack.last().map(|t| t.id)
6661    }
6662}
6663
6664impl Excerpt {
6665    fn new(
6666        id: ExcerptId,
6667        locator: Locator,
6668        buffer_id: BufferId,
6669        buffer: BufferSnapshot,
6670        range: ExcerptRange<text::Anchor>,
6671        has_trailing_newline: bool,
6672    ) -> Self {
6673        Excerpt {
6674            id,
6675            locator,
6676            max_buffer_row: range.context.end.to_point(&buffer).row,
6677            text_summary: buffer
6678                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6679            buffer_id,
6680            buffer,
6681            range,
6682            has_trailing_newline,
6683        }
6684    }
6685
6686    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6687        let content_start = self.range.context.start.to_offset(&self.buffer);
6688        let chunks_start = content_start + range.start;
6689        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6690
6691        let footer_height = if self.has_trailing_newline
6692            && range.start <= self.text_summary.len
6693            && range.end > self.text_summary.len
6694        {
6695            1
6696        } else {
6697            0
6698        };
6699
6700        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6701
6702        ExcerptChunks {
6703            excerpt_id: self.id,
6704            content_chunks,
6705            footer_height,
6706        }
6707    }
6708
6709    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6710        let content_start = self.range.context.start.to_offset(&self.buffer);
6711        let chunks_start = content_start + range.start;
6712        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6713        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6714        excerpt_chunks.footer_height = if self.has_trailing_newline
6715            && range.start <= self.text_summary.len
6716            && range.end > self.text_summary.len
6717        {
6718            1
6719        } else {
6720            0
6721        };
6722    }
6723
6724    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6725        if text_anchor
6726            .cmp(&self.range.context.start, &self.buffer)
6727            .is_lt()
6728        {
6729            self.range.context.start
6730        } else if text_anchor
6731            .cmp(&self.range.context.end, &self.buffer)
6732            .is_gt()
6733        {
6734            self.range.context.end
6735        } else {
6736            text_anchor
6737        }
6738    }
6739
6740    fn contains(&self, anchor: &Anchor) -> bool {
6741        Some(self.buffer_id) == anchor.buffer_id
6742            && self
6743                .range
6744                .context
6745                .start
6746                .cmp(&anchor.text_anchor, &self.buffer)
6747                .is_le()
6748            && self
6749                .range
6750                .context
6751                .end
6752                .cmp(&anchor.text_anchor, &self.buffer)
6753                .is_ge()
6754    }
6755
6756    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6757    fn buffer_start_offset(&self) -> usize {
6758        self.range.context.start.to_offset(&self.buffer)
6759    }
6760
6761    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6762    fn buffer_end_offset(&self) -> usize {
6763        self.buffer_start_offset() + self.text_summary.len
6764    }
6765}
6766
6767impl<'a> MultiBufferExcerpt<'a> {
6768    pub fn id(&self) -> ExcerptId {
6769        self.excerpt.id
6770    }
6771
6772    pub fn buffer_id(&self) -> BufferId {
6773        self.excerpt.buffer_id
6774    }
6775
6776    pub fn start_anchor(&self) -> Anchor {
6777        Anchor {
6778            buffer_id: Some(self.excerpt.buffer_id),
6779            excerpt_id: self.excerpt.id,
6780            text_anchor: self.excerpt.range.context.start,
6781            diff_base_anchor: None,
6782        }
6783    }
6784
6785    pub fn end_anchor(&self) -> Anchor {
6786        Anchor {
6787            buffer_id: Some(self.excerpt.buffer_id),
6788            excerpt_id: self.excerpt.id,
6789            text_anchor: self.excerpt.range.context.end,
6790            diff_base_anchor: None,
6791        }
6792    }
6793
6794    pub fn buffer(&self) -> &'a BufferSnapshot {
6795        &self.excerpt.buffer
6796    }
6797
6798    pub fn buffer_range(&self) -> Range<usize> {
6799        self.buffer_offset
6800            ..self
6801                .excerpt
6802                .range
6803                .context
6804                .end
6805                .to_offset(&self.excerpt.buffer.text)
6806    }
6807
6808    pub fn start_offset(&self) -> usize {
6809        self.offset
6810    }
6811
6812    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6813    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6814        self.map_range_to_buffer(offset..offset).start
6815    }
6816
6817    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6818    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6819        self.diff_transforms
6820            .seek(&OutputDimension(range.start), Bias::Right, &());
6821        let start = self.map_offset_to_buffer_internal(range.start);
6822        let end = if range.end > range.start {
6823            self.diff_transforms
6824                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6825            self.map_offset_to_buffer_internal(range.end)
6826        } else {
6827            start
6828        };
6829        start..end
6830    }
6831
6832    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6833        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6834        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6835            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6836        };
6837        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6838        self.buffer_offset + offset_in_excerpt
6839    }
6840
6841    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6842    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6843        self.map_range_from_buffer(buffer_offset..buffer_offset)
6844            .start
6845    }
6846
6847    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6848    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6849        if buffer_range.start < self.buffer_offset {
6850            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6851            return buffer_range;
6852        }
6853        let overshoot = buffer_range.start - self.buffer_offset;
6854        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6855        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6856        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6857            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6858            return buffer_range;
6859        }
6860        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6861        let start = self.diff_transforms.start().0 .0 + overshoot;
6862
6863        let end = if buffer_range.end > buffer_range.start {
6864            let overshoot = buffer_range.end - self.buffer_offset;
6865            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6866            self.diff_transforms
6867                .seek_forward(&excerpt_offset, Bias::Right, &());
6868            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6869            self.diff_transforms.start().0 .0 + overshoot
6870        } else {
6871            start
6872        };
6873
6874        start..end
6875    }
6876
6877    /// Returns true if the entirety of the given range is in the buffer's excerpt
6878    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6879        range.start >= self.excerpt.buffer_start_offset()
6880            && range.end <= self.excerpt.buffer_end_offset()
6881    }
6882
6883    pub fn max_buffer_row(&self) -> u32 {
6884        self.excerpt.max_buffer_row
6885    }
6886}
6887
6888impl ExcerptId {
6889    pub fn min() -> Self {
6890        Self(0)
6891    }
6892
6893    pub fn max() -> Self {
6894        Self(usize::MAX)
6895    }
6896
6897    pub fn to_proto(&self) -> u64 {
6898        self.0 as _
6899    }
6900
6901    pub fn from_proto(proto: u64) -> Self {
6902        Self(proto as _)
6903    }
6904
6905    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6906        let a = snapshot.excerpt_locator_for_id(*self);
6907        let b = snapshot.excerpt_locator_for_id(*other);
6908        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6909    }
6910}
6911
6912impl From<ExcerptId> for usize {
6913    fn from(val: ExcerptId) -> Self {
6914        val.0
6915    }
6916}
6917
6918impl fmt::Debug for Excerpt {
6919    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6920        f.debug_struct("Excerpt")
6921            .field("id", &self.id)
6922            .field("locator", &self.locator)
6923            .field("buffer_id", &self.buffer_id)
6924            .field("range", &self.range)
6925            .field("text_summary", &self.text_summary)
6926            .field("has_trailing_newline", &self.has_trailing_newline)
6927            .finish()
6928    }
6929}
6930
6931impl sum_tree::Item for Excerpt {
6932    type Summary = ExcerptSummary;
6933
6934    fn summary(&self, _cx: &()) -> Self::Summary {
6935        let mut text = self.text_summary;
6936        if self.has_trailing_newline {
6937            text += TextSummary::from("\n");
6938        }
6939        ExcerptSummary {
6940            excerpt_id: self.id,
6941            excerpt_locator: self.locator.clone(),
6942            widest_line_number: self.max_buffer_row,
6943            text,
6944        }
6945    }
6946}
6947
6948impl sum_tree::Item for ExcerptIdMapping {
6949    type Summary = ExcerptId;
6950
6951    fn summary(&self, _cx: &()) -> Self::Summary {
6952        self.id
6953    }
6954}
6955
6956impl sum_tree::KeyedItem for ExcerptIdMapping {
6957    type Key = ExcerptId;
6958
6959    fn key(&self) -> Self::Key {
6960        self.id
6961    }
6962}
6963
6964impl DiffTransform {
6965    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6966        match self {
6967            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6968            DiffTransform::BufferContent {
6969                inserted_hunk_info, ..
6970            } => *inserted_hunk_info,
6971        }
6972    }
6973}
6974
6975impl sum_tree::Item for DiffTransform {
6976    type Summary = DiffTransformSummary;
6977
6978    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6979        match self {
6980            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6981                input: *summary,
6982                output: *summary,
6983            },
6984            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6985                input: TextSummary::default(),
6986                output: *summary,
6987            },
6988        }
6989    }
6990}
6991
6992impl DiffTransformSummary {
6993    fn excerpt_len(&self) -> ExcerptOffset {
6994        ExcerptOffset::new(self.input.len)
6995    }
6996}
6997
6998impl sum_tree::Summary for DiffTransformSummary {
6999    type Context = ();
7000
7001    fn zero(_: &Self::Context) -> Self {
7002        DiffTransformSummary {
7003            input: TextSummary::default(),
7004            output: TextSummary::default(),
7005        }
7006    }
7007
7008    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7009        self.input += &summary.input;
7010        self.output += &summary.output;
7011    }
7012}
7013
7014impl sum_tree::Summary for ExcerptId {
7015    type Context = ();
7016
7017    fn zero(_cx: &()) -> Self {
7018        Default::default()
7019    }
7020
7021    fn add_summary(&mut self, other: &Self, _: &()) {
7022        *self = *other;
7023    }
7024}
7025
7026impl sum_tree::Summary for ExcerptSummary {
7027    type Context = ();
7028
7029    fn zero(_cx: &()) -> Self {
7030        Default::default()
7031    }
7032
7033    fn add_summary(&mut self, summary: &Self, _: &()) {
7034        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7035        self.excerpt_locator = summary.excerpt_locator.clone();
7036        self.text.add_summary(&summary.text, &());
7037        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7038    }
7039}
7040
7041impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7042    fn zero(_cx: &()) -> Self {
7043        Default::default()
7044    }
7045
7046    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7047        self.value += summary.text.len;
7048    }
7049}
7050
7051impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7052    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7053        Ord::cmp(&self.value, &cursor_location.text.len)
7054    }
7055}
7056
7057impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7058    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7059        Ord::cmp(&Some(self), cursor_location)
7060    }
7061}
7062
7063impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7064    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7065        Ord::cmp(self, &cursor_location.excerpt_locator)
7066    }
7067}
7068
7069impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7070    fn zero(_cx: &()) -> Self {
7071        Default::default()
7072    }
7073
7074    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7075        self.value += summary.text.lines;
7076    }
7077}
7078
7079impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7080    for ExcerptDimension<D>
7081{
7082    fn zero(_: &()) -> Self {
7083        ExcerptDimension(D::default())
7084    }
7085
7086    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7087        self.0.add_assign(&D::from_text_summary(&summary.text))
7088    }
7089}
7090
7091impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7092    fn zero(_cx: &()) -> Self {
7093        Default::default()
7094    }
7095
7096    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7097        *self = Some(&summary.excerpt_locator);
7098    }
7099}
7100
7101impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7102    fn zero(_cx: &()) -> Self {
7103        Default::default()
7104    }
7105
7106    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7107        *self = Some(summary.excerpt_id);
7108    }
7109}
7110
7111#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7112struct ExcerptDimension<T>(T);
7113
7114#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7115struct OutputDimension<T>(T);
7116
7117impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7118    fn zero(_: &()) -> Self {
7119        ExcerptOffset::new(0)
7120    }
7121
7122    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7123        self.value += summary.input.len;
7124    }
7125}
7126
7127impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7128    fn zero(_: &()) -> Self {
7129        ExcerptPoint::new(0, 0)
7130    }
7131
7132    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7133        self.value += summary.input.lines;
7134    }
7135}
7136
7137impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7138    for ExcerptDimension<D>
7139{
7140    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7141        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7142    }
7143}
7144
7145impl<D: TextDimension + Ord>
7146    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7147    for ExcerptDimension<D>
7148{
7149    fn cmp(
7150        &self,
7151        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7152        _: &(),
7153    ) -> cmp::Ordering {
7154        Ord::cmp(&self.0, &cursor_location.1 .0)
7155    }
7156}
7157
7158impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7159    fn zero(_: &()) -> Self {
7160        ExcerptDimension(D::default())
7161    }
7162
7163    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7164        self.0.add_assign(&D::from_text_summary(&summary.input))
7165    }
7166}
7167
7168impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7169    fn zero(_: &()) -> Self {
7170        OutputDimension(D::default())
7171    }
7172
7173    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7174        self.0.add_assign(&D::from_text_summary(&summary.output))
7175    }
7176}
7177
7178impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7179    fn zero(_: &()) -> Self {
7180        TextSummary::default()
7181    }
7182
7183    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7184        *self += summary.output
7185    }
7186}
7187
7188impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7189    fn zero(_: &()) -> Self {
7190        0
7191    }
7192
7193    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7194        *self += summary.output.len
7195    }
7196}
7197
7198impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7199    fn zero(_: &()) -> Self {
7200        Point::new(0, 0)
7201    }
7202
7203    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7204        *self += summary.output.lines
7205    }
7206}
7207
7208impl MultiBufferRows<'_> {
7209    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7210        self.point = Point::new(row, 0);
7211        self.cursor.seek(&self.point);
7212    }
7213}
7214
7215impl Iterator for MultiBufferRows<'_> {
7216    type Item = RowInfo;
7217
7218    fn next(&mut self) -> Option<Self::Item> {
7219        if self.is_empty && self.point.row == 0 {
7220            self.point += Point::new(1, 0);
7221            return Some(RowInfo {
7222                buffer_id: None,
7223                buffer_row: Some(0),
7224                multibuffer_row: Some(MultiBufferRow(0)),
7225                diff_status: None,
7226                expand_info: None,
7227            });
7228        }
7229
7230        let mut region = self.cursor.region()?;
7231        while self.point >= region.range.end {
7232            self.cursor.next();
7233            if let Some(next_region) = self.cursor.region() {
7234                region = next_region;
7235            } else {
7236                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7237                    let multibuffer_row = MultiBufferRow(self.point.row);
7238                    let last_excerpt = self
7239                        .cursor
7240                        .excerpts
7241                        .item()
7242                        .or(self.cursor.excerpts.prev_item())?;
7243                    let last_row = last_excerpt
7244                        .range
7245                        .context
7246                        .end
7247                        .to_point(&last_excerpt.buffer)
7248                        .row;
7249
7250                    let first_row = last_excerpt
7251                        .range
7252                        .context
7253                        .start
7254                        .to_point(&last_excerpt.buffer)
7255                        .row;
7256
7257                    let expand_info = if self.is_singleton {
7258                        None
7259                    } else {
7260                        let needs_expand_up = first_row == last_row
7261                            && last_row > 0
7262                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7263                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7264
7265                        if needs_expand_up && needs_expand_down {
7266                            Some(ExpandExcerptDirection::UpAndDown)
7267                        } else if needs_expand_up {
7268                            Some(ExpandExcerptDirection::Up)
7269                        } else if needs_expand_down {
7270                            Some(ExpandExcerptDirection::Down)
7271                        } else {
7272                            None
7273                        }
7274                        .map(|direction| ExpandInfo {
7275                            direction,
7276                            excerpt_id: last_excerpt.id,
7277                        })
7278                    };
7279                    self.point += Point::new(1, 0);
7280                    return Some(RowInfo {
7281                        buffer_id: Some(last_excerpt.buffer_id),
7282                        buffer_row: Some(last_row),
7283                        multibuffer_row: Some(multibuffer_row),
7284                        diff_status: None,
7285                        expand_info,
7286                    });
7287                } else {
7288                    return None;
7289                }
7290            };
7291        }
7292
7293        let overshoot = self.point - region.range.start;
7294        let buffer_point = region.buffer_range.start + overshoot;
7295        let expand_info = if self.is_singleton {
7296            None
7297        } else {
7298            let needs_expand_up = self.point.row == region.range.start.row
7299                && self.cursor.is_at_start_of_excerpt()
7300                && buffer_point.row > 0;
7301            let needs_expand_down = (region.excerpt.has_trailing_newline
7302                && self.point.row + 1 == region.range.end.row
7303                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7304                && self.cursor.is_at_end_of_excerpt()
7305                && buffer_point.row < region.buffer.max_point().row;
7306
7307            if needs_expand_up && needs_expand_down {
7308                Some(ExpandExcerptDirection::UpAndDown)
7309            } else if needs_expand_up {
7310                Some(ExpandExcerptDirection::Up)
7311            } else if needs_expand_down {
7312                Some(ExpandExcerptDirection::Down)
7313            } else {
7314                None
7315            }
7316            .map(|direction| ExpandInfo {
7317                direction,
7318                excerpt_id: region.excerpt.id,
7319            })
7320        };
7321
7322        let result = Some(RowInfo {
7323            buffer_id: Some(region.buffer.remote_id()),
7324            buffer_row: Some(buffer_point.row),
7325            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7326            diff_status: region
7327                .diff_hunk_status
7328                .filter(|_| self.point < region.range.end),
7329            expand_info,
7330        });
7331        self.point += Point::new(1, 0);
7332        result
7333    }
7334}
7335
7336impl<'a> MultiBufferChunks<'a> {
7337    pub fn offset(&self) -> usize {
7338        self.range.start
7339    }
7340
7341    pub fn seek(&mut self, range: Range<usize>) {
7342        self.diff_transforms.seek(&range.end, Bias::Right, &());
7343        let mut excerpt_end = self.diff_transforms.start().1;
7344        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7345            let overshoot = range.end - self.diff_transforms.start().0;
7346            excerpt_end.value += overshoot;
7347        }
7348
7349        self.diff_transforms.seek(&range.start, Bias::Right, &());
7350        let mut excerpt_start = self.diff_transforms.start().1;
7351        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7352            let overshoot = range.start - self.diff_transforms.start().0;
7353            excerpt_start.value += overshoot;
7354        }
7355
7356        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7357        self.buffer_chunk.take();
7358        self.range = range;
7359    }
7360
7361    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7362        self.excerpt_offset_range = new_range.clone();
7363        self.excerpts.seek(&new_range.start, Bias::Right, &());
7364        if let Some(excerpt) = self.excerpts.item() {
7365            let excerpt_start = *self.excerpts.start();
7366            if let Some(excerpt_chunks) = self
7367                .excerpt_chunks
7368                .as_mut()
7369                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7370            {
7371                excerpt.seek_chunks(
7372                    excerpt_chunks,
7373                    (self.excerpt_offset_range.start - excerpt_start).value
7374                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7375                );
7376            } else {
7377                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7378                    (self.excerpt_offset_range.start - excerpt_start).value
7379                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7380                    self.language_aware,
7381                ));
7382            }
7383        } else {
7384            self.excerpt_chunks = None;
7385        }
7386    }
7387
7388    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7389        loop {
7390            if self.excerpt_offset_range.is_empty() {
7391                return None;
7392            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7393                self.excerpt_offset_range.start.value += chunk.text.len();
7394                return Some(chunk);
7395            } else {
7396                self.excerpts.next(&());
7397                let excerpt = self.excerpts.item()?;
7398                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7399                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7400                    self.language_aware,
7401                ));
7402            }
7403        }
7404    }
7405}
7406
7407impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7408    type Item = &'a str;
7409
7410    fn next(&mut self) -> Option<Self::Item> {
7411        let mut region = self.cursor.region()?;
7412        if self.offset == region.range.start {
7413            self.cursor.prev();
7414            region = self.cursor.region()?;
7415            let start_overshoot = self.start.saturating_sub(region.range.start);
7416            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7417                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7418            ));
7419        }
7420
7421        if self.offset == region.range.end && region.has_trailing_newline {
7422            self.offset -= 1;
7423            Some("\n")
7424        } else {
7425            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7426            self.offset -= chunk.len();
7427            Some(chunk)
7428        }
7429    }
7430}
7431
7432impl<'a> Iterator for MultiBufferChunks<'a> {
7433    type Item = Chunk<'a>;
7434
7435    fn next(&mut self) -> Option<Chunk<'a>> {
7436        if self.range.start >= self.range.end {
7437            return None;
7438        }
7439        if self.range.start == self.diff_transforms.end(&()).0 {
7440            self.diff_transforms.next(&());
7441        }
7442
7443        let diff_transform_start = self.diff_transforms.start().0;
7444        let diff_transform_end = self.diff_transforms.end(&()).0;
7445        debug_assert!(self.range.start < diff_transform_end);
7446
7447        let diff_transform = self.diff_transforms.item()?;
7448        match diff_transform {
7449            DiffTransform::BufferContent { .. } => {
7450                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7451                    chunk
7452                } else {
7453                    let chunk = self.next_excerpt_chunk().unwrap();
7454                    self.buffer_chunk.insert(chunk)
7455                };
7456
7457                let chunk_end = self.range.start + chunk.text.len();
7458                let diff_transform_end = diff_transform_end.min(self.range.end);
7459
7460                if diff_transform_end < chunk_end {
7461                    let (before, after) =
7462                        chunk.text.split_at(diff_transform_end - self.range.start);
7463                    self.range.start = diff_transform_end;
7464                    chunk.text = after;
7465                    Some(Chunk {
7466                        text: before,
7467                        ..chunk.clone()
7468                    })
7469                } else {
7470                    self.range.start = chunk_end;
7471                    self.buffer_chunk.take()
7472                }
7473            }
7474            DiffTransform::DeletedHunk {
7475                buffer_id,
7476                base_text_byte_range,
7477                has_trailing_newline,
7478                ..
7479            } => {
7480                let base_text_start =
7481                    base_text_byte_range.start + self.range.start - diff_transform_start;
7482                let base_text_end =
7483                    base_text_byte_range.start + self.range.end - diff_transform_start;
7484                let base_text_end = base_text_end.min(base_text_byte_range.end);
7485
7486                let mut chunks = if let Some((_, mut chunks)) = self
7487                    .diff_base_chunks
7488                    .take()
7489                    .filter(|(id, _)| id == buffer_id)
7490                {
7491                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7492                    {
7493                        chunks.seek(base_text_start..base_text_end);
7494                    }
7495                    chunks
7496                } else {
7497                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7498                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7499                };
7500
7501                let chunk = if let Some(chunk) = chunks.next() {
7502                    self.range.start += chunk.text.len();
7503                    self.diff_base_chunks = Some((*buffer_id, chunks));
7504                    chunk
7505                } else {
7506                    debug_assert!(has_trailing_newline);
7507                    self.range.start += "\n".len();
7508                    Chunk {
7509                        text: "\n",
7510                        ..Default::default()
7511                    }
7512                };
7513                Some(chunk)
7514            }
7515        }
7516    }
7517}
7518
7519impl MultiBufferBytes<'_> {
7520    fn consume(&mut self, len: usize) {
7521        self.range.start += len;
7522        self.chunk = &self.chunk[len..];
7523
7524        if !self.range.is_empty() && self.chunk.is_empty() {
7525            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7526                self.chunk = chunk;
7527            } else if self.has_trailing_newline {
7528                self.has_trailing_newline = false;
7529                self.chunk = b"\n";
7530            } else {
7531                self.cursor.next();
7532                if let Some(region) = self.cursor.region() {
7533                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7534                        region.buffer_range.start
7535                            ..(region.buffer_range.start + self.range.end - region.range.start)
7536                                .min(region.buffer_range.end),
7537                    );
7538                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7539                    self.excerpt_bytes = Some(excerpt_bytes);
7540                    self.has_trailing_newline =
7541                        region.has_trailing_newline && self.range.end >= region.range.end;
7542                    if self.chunk.is_empty() && self.has_trailing_newline {
7543                        self.has_trailing_newline = false;
7544                        self.chunk = b"\n";
7545                    }
7546                }
7547            }
7548        }
7549    }
7550}
7551
7552impl<'a> Iterator for MultiBufferBytes<'a> {
7553    type Item = &'a [u8];
7554
7555    fn next(&mut self) -> Option<Self::Item> {
7556        let chunk = self.chunk;
7557        if chunk.is_empty() {
7558            None
7559        } else {
7560            self.consume(chunk.len());
7561            Some(chunk)
7562        }
7563    }
7564}
7565
7566impl io::Read for MultiBufferBytes<'_> {
7567    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7568        let len = cmp::min(buf.len(), self.chunk.len());
7569        buf[..len].copy_from_slice(&self.chunk[..len]);
7570        if len > 0 {
7571            self.consume(len);
7572        }
7573        Ok(len)
7574    }
7575}
7576
7577impl io::Read for ReversedMultiBufferBytes<'_> {
7578    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7579        let len = cmp::min(buf.len(), self.chunk.len());
7580        buf[..len].copy_from_slice(&self.chunk[..len]);
7581        buf[..len].reverse();
7582        if len > 0 {
7583            self.range.end -= len;
7584            self.chunk = &self.chunk[..self.chunk.len() - len];
7585            if !self.range.is_empty() && self.chunk.is_empty() {
7586                if let Some(chunk) = self.chunks.next() {
7587                    self.chunk = chunk.as_bytes();
7588                }
7589            }
7590        }
7591        Ok(len)
7592    }
7593}
7594
7595impl<'a> Iterator for ExcerptChunks<'a> {
7596    type Item = Chunk<'a>;
7597
7598    fn next(&mut self) -> Option<Self::Item> {
7599        if let Some(chunk) = self.content_chunks.next() {
7600            return Some(chunk);
7601        }
7602
7603        if self.footer_height > 0 {
7604            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7605            self.footer_height = 0;
7606            return Some(Chunk {
7607                text,
7608                ..Default::default()
7609            });
7610        }
7611
7612        None
7613    }
7614}
7615
7616impl ToOffset for Point {
7617    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7618        snapshot.point_to_offset(*self)
7619    }
7620}
7621
7622impl ToOffset for usize {
7623    #[track_caller]
7624    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7625        assert!(*self <= snapshot.len(), "offset is out of range");
7626        *self
7627    }
7628}
7629
7630impl ToOffset for OffsetUtf16 {
7631    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7632        snapshot.offset_utf16_to_offset(*self)
7633    }
7634}
7635
7636impl ToOffset for PointUtf16 {
7637    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7638        snapshot.point_utf16_to_offset(*self)
7639    }
7640}
7641
7642impl ToOffsetUtf16 for OffsetUtf16 {
7643    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7644        *self
7645    }
7646}
7647
7648impl ToOffsetUtf16 for usize {
7649    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7650        snapshot.offset_to_offset_utf16(*self)
7651    }
7652}
7653
7654impl ToPoint for usize {
7655    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7656        snapshot.offset_to_point(*self)
7657    }
7658}
7659
7660impl ToPoint for Point {
7661    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7662        *self
7663    }
7664}
7665
7666impl ToPointUtf16 for usize {
7667    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7668        snapshot.offset_to_point_utf16(*self)
7669    }
7670}
7671
7672impl ToPointUtf16 for Point {
7673    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7674        snapshot.point_to_point_utf16(*self)
7675    }
7676}
7677
7678impl ToPointUtf16 for PointUtf16 {
7679    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7680        *self
7681    }
7682}
7683
7684impl From<ExcerptId> for EntityId {
7685    fn from(id: ExcerptId) -> Self {
7686        EntityId::from(id.0 as u64)
7687    }
7688}
7689
7690pub fn build_excerpt_ranges<T>(
7691    buffer: &BufferSnapshot,
7692    ranges: &[Range<T>],
7693    context_line_count: u32,
7694) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7695where
7696    T: text::ToPoint,
7697{
7698    let max_point = buffer.max_point();
7699    let mut range_counts = Vec::new();
7700    let mut excerpt_ranges = Vec::new();
7701    let mut range_iter = ranges
7702        .iter()
7703        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7704        .peekable();
7705    while let Some(range) = range_iter.next() {
7706        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7707        let row = (range.end.row + context_line_count).min(max_point.row);
7708        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7709
7710        let mut ranges_in_excerpt = 1;
7711
7712        while let Some(next_range) = range_iter.peek() {
7713            if next_range.start.row <= excerpt_end.row + context_line_count {
7714                let row = (next_range.end.row + context_line_count).min(max_point.row);
7715                excerpt_end = Point::new(row, buffer.line_len(row));
7716
7717                ranges_in_excerpt += 1;
7718                range_iter.next();
7719            } else {
7720                break;
7721            }
7722        }
7723
7724        excerpt_ranges.push(ExcerptRange {
7725            context: excerpt_start..excerpt_end,
7726            primary: Some(range),
7727        });
7728        range_counts.push(ranges_in_excerpt);
7729    }
7730
7731    (excerpt_ranges, range_counts)
7732}