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: Option<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.as_ref()) {
 357            (None, _) => true,
 358            (Some(_), None) => false,
 359            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 360        }
 361    }
 362}
 363
 364#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 365pub struct ExpandInfo {
 366    pub direction: ExpandExcerptDirection,
 367    pub excerpt_id: ExcerptId,
 368}
 369
 370#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 371pub struct RowInfo {
 372    pub buffer_id: Option<BufferId>,
 373    pub buffer_row: Option<u32>,
 374    pub multibuffer_row: Option<MultiBufferRow>,
 375    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 376    pub expand_info: Option<ExpandInfo>,
 377}
 378
 379/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 380#[derive(Clone)]
 381struct Excerpt {
 382    /// The unique identifier for this excerpt
 383    id: ExcerptId,
 384    /// The location of the excerpt in the [`MultiBuffer`]
 385    locator: Locator,
 386    /// The buffer being excerpted
 387    buffer_id: BufferId,
 388    /// A snapshot of the buffer being excerpted
 389    buffer: BufferSnapshot,
 390    /// The range of the buffer to be shown in the excerpt
 391    range: ExcerptRange<text::Anchor>,
 392    /// The last row in the excerpted slice of the buffer
 393    max_buffer_row: BufferRow,
 394    /// A summary of the text in the excerpt
 395    text_summary: TextSummary,
 396    has_trailing_newline: bool,
 397}
 398
 399/// A public view into an `Excerpt` in a [`MultiBuffer`].
 400///
 401/// Contains methods for getting the [`Buffer`] of the excerpt,
 402/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 403#[derive(Clone)]
 404pub struct MultiBufferExcerpt<'a> {
 405    excerpt: &'a Excerpt,
 406    diff_transforms:
 407        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 408    offset: usize,
 409    excerpt_offset: ExcerptDimension<usize>,
 410    buffer_offset: usize,
 411}
 412
 413#[derive(Clone, Debug)]
 414struct ExcerptIdMapping {
 415    id: ExcerptId,
 416    locator: Locator,
 417}
 418
 419/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 420/// These ranges are relative to the buffer itself
 421#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 422pub struct ExcerptRange<T> {
 423    /// The full range of text to be shown in the excerpt.
 424    pub context: Range<T>,
 425    /// The primary range of text to be highlighted in the excerpt.
 426    /// In a multi-buffer search, this would be the text that matched the search
 427    pub primary: Option<Range<T>>,
 428}
 429
 430#[derive(Clone, Debug, Default)]
 431pub struct ExcerptSummary {
 432    excerpt_id: ExcerptId,
 433    /// The location of the last [`Excerpt`] being summarized
 434    excerpt_locator: Locator,
 435    widest_line_number: u32,
 436    text: TextSummary,
 437}
 438
 439#[derive(Debug, Clone)]
 440pub struct DiffTransformSummary {
 441    input: TextSummary,
 442    output: TextSummary,
 443}
 444
 445#[derive(Clone)]
 446pub struct MultiBufferRows<'a> {
 447    point: Point,
 448    is_empty: bool,
 449    is_singleton: bool,
 450    cursor: MultiBufferCursor<'a, Point>,
 451}
 452
 453pub struct MultiBufferChunks<'a> {
 454    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 455    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 456    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 457    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 458    buffer_chunk: Option<Chunk<'a>>,
 459    range: Range<usize>,
 460    excerpt_offset_range: Range<ExcerptOffset>,
 461    excerpt_chunks: Option<ExcerptChunks<'a>>,
 462    language_aware: bool,
 463}
 464
 465pub struct ReversedMultiBufferChunks<'a> {
 466    cursor: MultiBufferCursor<'a, usize>,
 467    current_chunks: Option<rope::Chunks<'a>>,
 468    start: usize,
 469    offset: usize,
 470}
 471
 472pub struct MultiBufferBytes<'a> {
 473    range: Range<usize>,
 474    cursor: MultiBufferCursor<'a, usize>,
 475    excerpt_bytes: Option<text::Bytes<'a>>,
 476    has_trailing_newline: bool,
 477    chunk: &'a [u8],
 478}
 479
 480pub struct ReversedMultiBufferBytes<'a> {
 481    range: Range<usize>,
 482    chunks: ReversedMultiBufferChunks<'a>,
 483    chunk: &'a [u8],
 484}
 485
 486#[derive(Clone)]
 487struct MultiBufferCursor<'a, D: TextDimension> {
 488    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 489    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 490    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 491    cached_region: Option<MultiBufferRegion<'a, D>>,
 492}
 493
 494#[derive(Clone)]
 495struct MultiBufferRegion<'a, D: TextDimension> {
 496    buffer: &'a BufferSnapshot,
 497    is_main_buffer: bool,
 498    diff_hunk_status: Option<DiffHunkStatus>,
 499    excerpt: &'a Excerpt,
 500    buffer_range: Range<D>,
 501    range: Range<D>,
 502    has_trailing_newline: bool,
 503}
 504
 505struct ExcerptChunks<'a> {
 506    excerpt_id: ExcerptId,
 507    content_chunks: BufferChunks<'a>,
 508    footer_height: usize,
 509}
 510
 511#[derive(Debug)]
 512struct BufferEdit {
 513    range: Range<usize>,
 514    new_text: Arc<str>,
 515    is_insertion: bool,
 516    original_indent_column: Option<u32>,
 517    excerpt_id: ExcerptId,
 518}
 519
 520#[derive(Clone, Copy, Debug, PartialEq)]
 521enum DiffChangeKind {
 522    BufferEdited,
 523    DiffUpdated { base_changed: bool },
 524    ExpandOrCollapseHunks { expand: bool },
 525}
 526
 527#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 528pub enum ExpandExcerptDirection {
 529    Up,
 530    Down,
 531    UpAndDown,
 532}
 533
 534impl ExpandExcerptDirection {
 535    pub fn should_expand_up(&self) -> bool {
 536        match self {
 537            ExpandExcerptDirection::Up => true,
 538            ExpandExcerptDirection::Down => false,
 539            ExpandExcerptDirection::UpAndDown => true,
 540        }
 541    }
 542
 543    pub fn should_expand_down(&self) -> bool {
 544        match self {
 545            ExpandExcerptDirection::Up => false,
 546            ExpandExcerptDirection::Down => true,
 547            ExpandExcerptDirection::UpAndDown => true,
 548        }
 549    }
 550}
 551
 552#[derive(Clone, Debug, PartialEq)]
 553pub struct IndentGuide {
 554    pub buffer_id: BufferId,
 555    pub start_row: MultiBufferRow,
 556    pub end_row: MultiBufferRow,
 557    pub depth: u32,
 558    pub tab_size: u32,
 559    pub settings: IndentGuideSettings,
 560}
 561
 562impl IndentGuide {
 563    pub fn indent_level(&self) -> u32 {
 564        self.depth * self.tab_size
 565    }
 566}
 567
 568impl MultiBuffer {
 569    pub fn new(capability: Capability) -> Self {
 570        Self {
 571            snapshot: RefCell::new(MultiBufferSnapshot {
 572                show_headers: true,
 573                ..MultiBufferSnapshot::default()
 574            }),
 575            buffers: RefCell::default(),
 576            diffs: HashMap::default(),
 577            subscriptions: Topic::default(),
 578            singleton: false,
 579            capability,
 580            title: None,
 581            excerpts_by_path: Default::default(),
 582            paths_by_excerpt: Default::default(),
 583            buffer_changed_since_sync: Default::default(),
 584            history: History {
 585                next_transaction_id: clock::Lamport::default(),
 586                undo_stack: Vec::new(),
 587                redo_stack: Vec::new(),
 588                transaction_depth: 0,
 589                group_interval: Duration::from_millis(300),
 590            },
 591        }
 592    }
 593
 594    pub fn without_headers(capability: Capability) -> Self {
 595        Self {
 596            snapshot: Default::default(),
 597            buffers: Default::default(),
 598            excerpts_by_path: Default::default(),
 599            paths_by_excerpt: Default::default(),
 600            diffs: HashMap::default(),
 601            subscriptions: Default::default(),
 602            singleton: false,
 603            capability,
 604            buffer_changed_since_sync: Default::default(),
 605            history: History {
 606                next_transaction_id: Default::default(),
 607                undo_stack: Default::default(),
 608                redo_stack: Default::default(),
 609                transaction_depth: 0,
 610                group_interval: Duration::from_millis(300),
 611            },
 612            title: Default::default(),
 613        }
 614    }
 615
 616    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 617        let mut buffers = HashMap::default();
 618        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 619        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 620            buffer_state.buffer.update(new_cx, |buffer, _| {
 621                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 622            });
 623            buffers.insert(
 624                *buffer_id,
 625                BufferState {
 626                    buffer: buffer_state.buffer.clone(),
 627                    last_version: buffer_state.last_version.clone(),
 628                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 629                    excerpts: buffer_state.excerpts.clone(),
 630                    _subscriptions: [
 631                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 632                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 633                    ],
 634                },
 635            );
 636        }
 637        let mut diff_bases = HashMap::default();
 638        for (buffer_id, diff) in self.diffs.iter() {
 639            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 640        }
 641        Self {
 642            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 643            buffers: RefCell::new(buffers),
 644            excerpts_by_path: Default::default(),
 645            paths_by_excerpt: Default::default(),
 646            diffs: diff_bases,
 647            subscriptions: Default::default(),
 648            singleton: self.singleton,
 649            capability: self.capability,
 650            history: self.history.clone(),
 651            title: self.title.clone(),
 652            buffer_changed_since_sync,
 653        }
 654    }
 655
 656    pub fn with_title(mut self, title: String) -> Self {
 657        self.title = Some(title);
 658        self
 659    }
 660
 661    pub fn read_only(&self) -> bool {
 662        self.capability == Capability::ReadOnly
 663    }
 664
 665    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 666        let mut this = Self::new(buffer.read(cx).capability());
 667        this.singleton = true;
 668        this.push_excerpts(
 669            buffer,
 670            [ExcerptRange {
 671                context: text::Anchor::MIN..text::Anchor::MAX,
 672                primary: None,
 673            }],
 674            cx,
 675        );
 676        this.snapshot.borrow_mut().singleton = true;
 677        this
 678    }
 679
 680    /// Returns an up-to-date snapshot of the MultiBuffer.
 681    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 682        self.sync(cx);
 683        self.snapshot.borrow().clone()
 684    }
 685
 686    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 687        self.sync(cx);
 688        self.snapshot.borrow()
 689    }
 690
 691    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 692        if self.singleton {
 693            return Some(
 694                self.buffers
 695                    .borrow()
 696                    .values()
 697                    .next()
 698                    .unwrap()
 699                    .buffer
 700                    .clone(),
 701            );
 702        } else {
 703            None
 704        }
 705    }
 706
 707    pub fn is_singleton(&self) -> bool {
 708        self.singleton
 709    }
 710
 711    pub fn subscribe(&mut self) -> Subscription {
 712        self.subscriptions.subscribe()
 713    }
 714
 715    pub fn is_dirty(&self, cx: &App) -> bool {
 716        self.read(cx).is_dirty()
 717    }
 718
 719    pub fn has_deleted_file(&self, cx: &App) -> bool {
 720        self.read(cx).has_deleted_file()
 721    }
 722
 723    pub fn has_conflict(&self, cx: &App) -> bool {
 724        self.read(cx).has_conflict()
 725    }
 726
 727    // The `is_empty` signature doesn't match what clippy expects
 728    #[allow(clippy::len_without_is_empty)]
 729    pub fn len(&self, cx: &App) -> usize {
 730        self.read(cx).len()
 731    }
 732
 733    pub fn is_empty(&self) -> bool {
 734        self.buffers.borrow().is_empty()
 735    }
 736
 737    pub fn symbols_containing<T: ToOffset>(
 738        &self,
 739        offset: T,
 740        theme: Option<&SyntaxTheme>,
 741        cx: &App,
 742    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 743        self.read(cx).symbols_containing(offset, theme)
 744    }
 745
 746    pub fn edit<I, S, T>(
 747        &self,
 748        edits: I,
 749        autoindent_mode: Option<AutoindentMode>,
 750        cx: &mut Context<Self>,
 751    ) where
 752        I: IntoIterator<Item = (Range<S>, T)>,
 753        S: ToOffset,
 754        T: Into<Arc<str>>,
 755    {
 756        let snapshot = self.read(cx);
 757        let edits = edits
 758            .into_iter()
 759            .map(|(range, new_text)| {
 760                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 761                if range.start > range.end {
 762                    mem::swap(&mut range.start, &mut range.end);
 763                }
 764                (range, new_text.into())
 765            })
 766            .collect::<Vec<_>>();
 767
 768        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 769
 770        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 771        fn edit_internal(
 772            this: &MultiBuffer,
 773            snapshot: Ref<MultiBufferSnapshot>,
 774            edits: Vec<(Range<usize>, Arc<str>)>,
 775            mut autoindent_mode: Option<AutoindentMode>,
 776            cx: &mut Context<MultiBuffer>,
 777        ) {
 778            if this.read_only() || this.buffers.borrow().is_empty() {
 779                return;
 780            }
 781
 782            let original_indent_columns = match &mut autoindent_mode {
 783                Some(AutoindentMode::Block {
 784                    original_indent_columns,
 785                }) => mem::take(original_indent_columns),
 786                _ => Default::default(),
 787            };
 788
 789            let (buffer_edits, edited_excerpt_ids) =
 790                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 791            drop(snapshot);
 792
 793            let mut buffer_ids = Vec::new();
 794            for (buffer_id, mut edits) in buffer_edits {
 795                buffer_ids.push(buffer_id);
 796                edits.sort_by_key(|edit| edit.range.start);
 797                this.buffers.borrow()[&buffer_id]
 798                    .buffer
 799                    .update(cx, |buffer, cx| {
 800                        let mut edits = edits.into_iter().peekable();
 801                        let mut insertions = Vec::new();
 802                        let mut original_indent_columns = Vec::new();
 803                        let mut deletions = Vec::new();
 804                        let empty_str: Arc<str> = Arc::default();
 805                        while let Some(BufferEdit {
 806                            mut range,
 807                            mut new_text,
 808                            mut is_insertion,
 809                            original_indent_column,
 810                            excerpt_id,
 811                        }) = edits.next()
 812                        {
 813                            while let Some(BufferEdit {
 814                                range: next_range,
 815                                is_insertion: next_is_insertion,
 816                                new_text: next_new_text,
 817                                excerpt_id: next_excerpt_id,
 818                                ..
 819                            }) = edits.peek()
 820                            {
 821                                if range.end >= next_range.start {
 822                                    range.end = cmp::max(next_range.end, range.end);
 823                                    is_insertion |= *next_is_insertion;
 824                                    if excerpt_id == *next_excerpt_id {
 825                                        new_text = format!("{new_text}{next_new_text}").into();
 826                                    }
 827                                    edits.next();
 828                                } else {
 829                                    break;
 830                                }
 831                            }
 832
 833                            if is_insertion {
 834                                original_indent_columns.push(original_indent_column);
 835                                insertions.push((
 836                                    buffer.anchor_before(range.start)
 837                                        ..buffer.anchor_before(range.end),
 838                                    new_text.clone(),
 839                                ));
 840                            } else if !range.is_empty() {
 841                                deletions.push((
 842                                    buffer.anchor_before(range.start)
 843                                        ..buffer.anchor_before(range.end),
 844                                    empty_str.clone(),
 845                                ));
 846                            }
 847                        }
 848
 849                        let deletion_autoindent_mode =
 850                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 851                                Some(AutoindentMode::Block {
 852                                    original_indent_columns: Default::default(),
 853                                })
 854                            } else {
 855                                autoindent_mode.clone()
 856                            };
 857                        let insertion_autoindent_mode =
 858                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 859                                Some(AutoindentMode::Block {
 860                                    original_indent_columns,
 861                                })
 862                            } else {
 863                                autoindent_mode.clone()
 864                            };
 865
 866                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 867                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 868                    })
 869            }
 870
 871            cx.emit(Event::ExcerptsEdited {
 872                excerpt_ids: edited_excerpt_ids,
 873                buffer_ids,
 874            });
 875        }
 876    }
 877
 878    fn convert_edits_to_buffer_edits(
 879        &self,
 880        edits: Vec<(Range<usize>, Arc<str>)>,
 881        snapshot: &MultiBufferSnapshot,
 882        original_indent_columns: &[Option<u32>],
 883    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 884        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 885        let mut edited_excerpt_ids = Vec::new();
 886        let mut cursor = snapshot.cursor::<usize>();
 887        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 888            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 889
 890            cursor.seek(&range.start);
 891            let mut start_region = cursor.region().expect("start offset out of bounds");
 892            if !start_region.is_main_buffer {
 893                cursor.next();
 894                if let Some(region) = cursor.region() {
 895                    start_region = region;
 896                } else {
 897                    continue;
 898                }
 899            }
 900
 901            if range.end < start_region.range.start {
 902                continue;
 903            }
 904
 905            if range.end > start_region.range.end {
 906                cursor.seek_forward(&range.end);
 907            }
 908            let mut end_region = cursor.region().expect("end offset out of bounds");
 909            if !end_region.is_main_buffer {
 910                cursor.prev();
 911                if let Some(region) = cursor.region() {
 912                    end_region = region;
 913                } else {
 914                    continue;
 915                }
 916            }
 917
 918            if range.start > end_region.range.end {
 919                continue;
 920            }
 921
 922            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 923            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 924            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 925                .min(start_region.buffer_range.end);
 926            let buffer_end =
 927                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 928
 929            if start_region.excerpt.id == end_region.excerpt.id {
 930                if start_region.is_main_buffer {
 931                    edited_excerpt_ids.push(start_region.excerpt.id);
 932                    buffer_edits
 933                        .entry(start_region.buffer.remote_id())
 934                        .or_default()
 935                        .push(BufferEdit {
 936                            range: buffer_start..buffer_end,
 937                            new_text,
 938                            is_insertion: true,
 939                            original_indent_column,
 940                            excerpt_id: start_region.excerpt.id,
 941                        });
 942                }
 943            } else {
 944                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 945                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 946                if start_region.is_main_buffer {
 947                    edited_excerpt_ids.push(start_region.excerpt.id);
 948                    buffer_edits
 949                        .entry(start_region.buffer.remote_id())
 950                        .or_default()
 951                        .push(BufferEdit {
 952                            range: start_excerpt_range,
 953                            new_text: new_text.clone(),
 954                            is_insertion: true,
 955                            original_indent_column,
 956                            excerpt_id: start_region.excerpt.id,
 957                        });
 958                }
 959                if end_region.is_main_buffer {
 960                    edited_excerpt_ids.push(end_region.excerpt.id);
 961                    buffer_edits
 962                        .entry(end_region.buffer.remote_id())
 963                        .or_default()
 964                        .push(BufferEdit {
 965                            range: end_excerpt_range,
 966                            new_text: new_text.clone(),
 967                            is_insertion: false,
 968                            original_indent_column,
 969                            excerpt_id: end_region.excerpt.id,
 970                        });
 971                }
 972
 973                cursor.seek(&range.start);
 974                cursor.next_excerpt();
 975                while let Some(region) = cursor.region() {
 976                    if region.excerpt.id == end_region.excerpt.id {
 977                        break;
 978                    }
 979                    if region.is_main_buffer {
 980                        edited_excerpt_ids.push(region.excerpt.id);
 981                        buffer_edits
 982                            .entry(region.buffer.remote_id())
 983                            .or_default()
 984                            .push(BufferEdit {
 985                                range: region.buffer_range,
 986                                new_text: new_text.clone(),
 987                                is_insertion: false,
 988                                original_indent_column,
 989                                excerpt_id: region.excerpt.id,
 990                            });
 991                    }
 992                    cursor.next_excerpt();
 993                }
 994            }
 995        }
 996        (buffer_edits, edited_excerpt_ids)
 997    }
 998
 999    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1000    where
1001        I: IntoIterator<Item = Range<S>>,
1002        S: ToOffset,
1003    {
1004        let snapshot = self.read(cx);
1005        let empty = Arc::<str>::from("");
1006        let edits = ranges
1007            .into_iter()
1008            .map(|range| {
1009                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1010                if range.start > range.end {
1011                    mem::swap(&mut range.start, &mut range.end);
1012                }
1013                (range, empty.clone())
1014            })
1015            .collect::<Vec<_>>();
1016
1017        return autoindent_ranges_internal(self, snapshot, edits, cx);
1018
1019        fn autoindent_ranges_internal(
1020            this: &MultiBuffer,
1021            snapshot: Ref<MultiBufferSnapshot>,
1022            edits: Vec<(Range<usize>, Arc<str>)>,
1023            cx: &mut Context<MultiBuffer>,
1024        ) {
1025            if this.read_only() || this.buffers.borrow().is_empty() {
1026                return;
1027            }
1028
1029            let (buffer_edits, edited_excerpt_ids) =
1030                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1031            drop(snapshot);
1032
1033            let mut buffer_ids = Vec::new();
1034            for (buffer_id, mut edits) in buffer_edits {
1035                buffer_ids.push(buffer_id);
1036                edits.sort_unstable_by_key(|edit| edit.range.start);
1037
1038                let mut ranges: Vec<Range<usize>> = Vec::new();
1039                for edit in edits {
1040                    if let Some(last_range) = ranges.last_mut() {
1041                        if edit.range.start <= last_range.end {
1042                            last_range.end = last_range.end.max(edit.range.end);
1043                            continue;
1044                        }
1045                    }
1046                    ranges.push(edit.range);
1047                }
1048
1049                this.buffers.borrow()[&buffer_id]
1050                    .buffer
1051                    .update(cx, |buffer, cx| {
1052                        buffer.autoindent_ranges(ranges, cx);
1053                    })
1054            }
1055
1056            cx.emit(Event::ExcerptsEdited {
1057                excerpt_ids: edited_excerpt_ids,
1058                buffer_ids,
1059            });
1060        }
1061    }
1062
1063    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1064    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1065    // Panics if the given position is invalid.
1066    pub fn insert_empty_line(
1067        &mut self,
1068        position: impl ToPoint,
1069        space_above: bool,
1070        space_below: bool,
1071        cx: &mut Context<Self>,
1072    ) -> Point {
1073        let multibuffer_point = position.to_point(&self.read(cx));
1074        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1075        self.start_transaction(cx);
1076        let empty_line_start = buffer.update(cx, |buffer, cx| {
1077            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1078        });
1079        self.end_transaction(cx);
1080        multibuffer_point + (empty_line_start - buffer_point)
1081    }
1082
1083    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1084        self.start_transaction_at(Instant::now(), cx)
1085    }
1086
1087    pub fn start_transaction_at(
1088        &mut self,
1089        now: Instant,
1090        cx: &mut Context<Self>,
1091    ) -> Option<TransactionId> {
1092        if let Some(buffer) = self.as_singleton() {
1093            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1094        }
1095
1096        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1097            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1098        }
1099        self.history.start_transaction(now)
1100    }
1101
1102    pub fn last_transaction_id(&self) -> Option<TransactionId> {
1103        let last_transaction = self.history.undo_stack.last()?;
1104        return Some(last_transaction.id);
1105    }
1106
1107    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1108        self.end_transaction_at(Instant::now(), cx)
1109    }
1110
1111    pub fn end_transaction_at(
1112        &mut self,
1113        now: Instant,
1114        cx: &mut Context<Self>,
1115    ) -> Option<TransactionId> {
1116        if let Some(buffer) = self.as_singleton() {
1117            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1118        }
1119
1120        let mut buffer_transactions = HashMap::default();
1121        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1122            if let Some(transaction_id) =
1123                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1124            {
1125                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1126            }
1127        }
1128
1129        if self.history.end_transaction(now, buffer_transactions) {
1130            let transaction_id = self.history.group().unwrap();
1131            Some(transaction_id)
1132        } else {
1133            None
1134        }
1135    }
1136
1137    pub fn edited_ranges_for_transaction<D>(
1138        &self,
1139        transaction_id: TransactionId,
1140        cx: &App,
1141    ) -> Vec<Range<D>>
1142    where
1143        D: TextDimension + Ord + Sub<D, Output = D>,
1144    {
1145        let Some(transaction) = self.history.transaction(transaction_id) else {
1146            return Vec::new();
1147        };
1148
1149        let mut ranges = Vec::new();
1150        let snapshot = self.read(cx);
1151        let buffers = self.buffers.borrow();
1152        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1153
1154        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1155            let Some(buffer_state) = buffers.get(buffer_id) else {
1156                continue;
1157            };
1158
1159            let buffer = buffer_state.buffer.read(cx);
1160            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1161                for excerpt_id in &buffer_state.excerpts {
1162                    cursor.seek(excerpt_id, Bias::Left, &());
1163                    if let Some(excerpt) = cursor.item() {
1164                        if excerpt.locator == *excerpt_id {
1165                            let excerpt_buffer_start =
1166                                excerpt.range.context.start.summary::<D>(buffer);
1167                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1168                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1169                            if excerpt_range.contains(&range.start)
1170                                && excerpt_range.contains(&range.end)
1171                            {
1172                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1173
1174                                let mut start = excerpt_start;
1175                                start.add_assign(&(range.start - excerpt_buffer_start));
1176                                let mut end = excerpt_start;
1177                                end.add_assign(&(range.end - excerpt_buffer_start));
1178
1179                                ranges.push(start..end);
1180                                break;
1181                            }
1182                        }
1183                    }
1184                }
1185            }
1186        }
1187
1188        ranges.sort_by_key(|range| range.start);
1189        ranges
1190    }
1191
1192    pub fn merge_transactions(
1193        &mut self,
1194        transaction: TransactionId,
1195        destination: TransactionId,
1196        cx: &mut Context<Self>,
1197    ) {
1198        if let Some(buffer) = self.as_singleton() {
1199            buffer.update(cx, |buffer, _| {
1200                buffer.merge_transactions(transaction, destination)
1201            });
1202        } else if let Some(transaction) = self.history.forget(transaction) {
1203            if let Some(destination) = self.history.transaction_mut(destination) {
1204                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1205                    if let Some(destination_buffer_transaction_id) =
1206                        destination.buffer_transactions.get(&buffer_id)
1207                    {
1208                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1209                            state.buffer.update(cx, |buffer, _| {
1210                                buffer.merge_transactions(
1211                                    buffer_transaction_id,
1212                                    *destination_buffer_transaction_id,
1213                                )
1214                            });
1215                        }
1216                    } else {
1217                        destination
1218                            .buffer_transactions
1219                            .insert(buffer_id, buffer_transaction_id);
1220                    }
1221                }
1222            }
1223        }
1224    }
1225
1226    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1227        self.history.finalize_last_transaction();
1228        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1229            buffer.update(cx, |buffer, _| {
1230                buffer.finalize_last_transaction();
1231            });
1232        }
1233    }
1234
1235    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1236    where
1237        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1238    {
1239        self.history
1240            .push_transaction(buffer_transactions, Instant::now(), cx);
1241        self.history.finalize_last_transaction();
1242    }
1243
1244    pub fn group_until_transaction(
1245        &mut self,
1246        transaction_id: TransactionId,
1247        cx: &mut Context<Self>,
1248    ) {
1249        if let Some(buffer) = self.as_singleton() {
1250            buffer.update(cx, |buffer, _| {
1251                buffer.group_until_transaction(transaction_id)
1252            });
1253        } else {
1254            self.history.group_until(transaction_id);
1255        }
1256    }
1257
1258    pub fn set_active_selections(
1259        &self,
1260        selections: &[Selection<Anchor>],
1261        line_mode: bool,
1262        cursor_shape: CursorShape,
1263        cx: &mut Context<Self>,
1264    ) {
1265        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1266            Default::default();
1267        let snapshot = self.read(cx);
1268        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1269        for selection in selections {
1270            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1271            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1272
1273            cursor.seek(&Some(start_locator), Bias::Left, &());
1274            while let Some(excerpt) = cursor.item() {
1275                if excerpt.locator > *end_locator {
1276                    break;
1277                }
1278
1279                let mut start = excerpt.range.context.start;
1280                let mut end = excerpt.range.context.end;
1281                if excerpt.id == selection.start.excerpt_id {
1282                    start = selection.start.text_anchor;
1283                }
1284                if excerpt.id == selection.end.excerpt_id {
1285                    end = selection.end.text_anchor;
1286                }
1287                selections_by_buffer
1288                    .entry(excerpt.buffer_id)
1289                    .or_default()
1290                    .push(Selection {
1291                        id: selection.id,
1292                        start,
1293                        end,
1294                        reversed: selection.reversed,
1295                        goal: selection.goal,
1296                    });
1297
1298                cursor.next(&());
1299            }
1300        }
1301
1302        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1303            if !selections_by_buffer.contains_key(buffer_id) {
1304                buffer_state
1305                    .buffer
1306                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1307            }
1308        }
1309
1310        for (buffer_id, mut selections) in selections_by_buffer {
1311            self.buffers.borrow()[&buffer_id]
1312                .buffer
1313                .update(cx, |buffer, cx| {
1314                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1315                    let mut selections = selections.into_iter().peekable();
1316                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1317                        let mut selection = selections.next()?;
1318                        while let Some(next_selection) = selections.peek() {
1319                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1320                                let next_selection = selections.next().unwrap();
1321                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1322                                    selection.end = next_selection.end;
1323                                }
1324                            } else {
1325                                break;
1326                            }
1327                        }
1328                        Some(selection)
1329                    }));
1330                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1331                });
1332        }
1333    }
1334
1335    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1336        for buffer in self.buffers.borrow().values() {
1337            buffer
1338                .buffer
1339                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1340        }
1341    }
1342
1343    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1344        let mut transaction_id = None;
1345        if let Some(buffer) = self.as_singleton() {
1346            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1347        } else {
1348            while let Some(transaction) = self.history.pop_undo() {
1349                let mut undone = false;
1350                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1351                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1352                        undone |= buffer.update(cx, |buffer, cx| {
1353                            let undo_to = *buffer_transaction_id;
1354                            if let Some(entry) = buffer.peek_undo_stack() {
1355                                *buffer_transaction_id = entry.transaction_id();
1356                            }
1357                            buffer.undo_to_transaction(undo_to, cx)
1358                        });
1359                    }
1360                }
1361
1362                if undone {
1363                    transaction_id = Some(transaction.id);
1364                    break;
1365                }
1366            }
1367        }
1368
1369        if let Some(transaction_id) = transaction_id {
1370            cx.emit(Event::TransactionUndone { transaction_id });
1371        }
1372
1373        transaction_id
1374    }
1375
1376    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1377        if let Some(buffer) = self.as_singleton() {
1378            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1379        }
1380
1381        while let Some(transaction) = self.history.pop_redo() {
1382            let mut redone = false;
1383            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1384                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1385                    redone |= buffer.update(cx, |buffer, cx| {
1386                        let redo_to = *buffer_transaction_id;
1387                        if let Some(entry) = buffer.peek_redo_stack() {
1388                            *buffer_transaction_id = entry.transaction_id();
1389                        }
1390                        buffer.redo_to_transaction(redo_to, cx)
1391                    });
1392                }
1393            }
1394
1395            if redone {
1396                return Some(transaction.id);
1397            }
1398        }
1399
1400        None
1401    }
1402
1403    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1404        if let Some(buffer) = self.as_singleton() {
1405            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1406        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1407            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1408                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1409                    buffer.update(cx, |buffer, cx| {
1410                        buffer.undo_transaction(*transaction_id, cx)
1411                    });
1412                }
1413            }
1414        }
1415    }
1416
1417    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1418        if let Some(buffer) = self.as_singleton() {
1419            buffer.update(cx, |buffer, _| {
1420                buffer.forget_transaction(transaction_id);
1421            });
1422        } else if let Some(transaction) = self.history.forget(transaction_id) {
1423            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1424                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1425                    state.buffer.update(cx, |buffer, _| {
1426                        buffer.forget_transaction(buffer_transaction_id);
1427                    });
1428                }
1429            }
1430        }
1431    }
1432
1433    pub fn push_excerpts<O>(
1434        &mut self,
1435        buffer: Entity<Buffer>,
1436        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1437        cx: &mut Context<Self>,
1438    ) -> Vec<ExcerptId>
1439    where
1440        O: text::ToOffset,
1441    {
1442        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1443    }
1444
1445    pub fn push_excerpts_with_context_lines<O>(
1446        &mut self,
1447        buffer: Entity<Buffer>,
1448        ranges: Vec<Range<O>>,
1449        context_line_count: u32,
1450        cx: &mut Context<Self>,
1451    ) -> Vec<Range<Anchor>>
1452    where
1453        O: text::ToPoint + text::ToOffset,
1454    {
1455        let buffer_id = buffer.read(cx).remote_id();
1456        let buffer_snapshot = buffer.read(cx).snapshot();
1457        let (excerpt_ranges, range_counts) =
1458            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1459
1460        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1461
1462        let mut anchor_ranges = Vec::new();
1463        let mut ranges = ranges.into_iter();
1464        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1465            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1466                let start = Anchor {
1467                    buffer_id: Some(buffer_id),
1468                    excerpt_id,
1469                    text_anchor: buffer_snapshot.anchor_after(range.start),
1470                    diff_base_anchor: None,
1471                };
1472                let end = Anchor {
1473                    buffer_id: Some(buffer_id),
1474                    excerpt_id,
1475                    text_anchor: buffer_snapshot.anchor_after(range.end),
1476                    diff_base_anchor: None,
1477                };
1478                start..end
1479            }))
1480        }
1481        anchor_ranges
1482    }
1483
1484    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1485        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1486        let snapshot = self.snapshot(cx);
1487        let excerpt = snapshot.excerpt(*excerpt_id)?;
1488        Some(Anchor::in_buffer(
1489            *excerpt_id,
1490            excerpt.buffer_id,
1491            excerpt.range.context.start,
1492        ))
1493    }
1494
1495    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1496        self.excerpts_by_path.keys()
1497    }
1498
1499    fn expand_excerpts_with_paths(
1500        &mut self,
1501        ids: impl IntoIterator<Item = ExcerptId>,
1502        line_count: u32,
1503        direction: ExpandExcerptDirection,
1504        cx: &mut Context<Self>,
1505    ) {
1506        let grouped = ids
1507            .into_iter()
1508            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1509            .into_iter()
1510            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1511            .collect::<Vec<_>>();
1512        let snapshot = self.snapshot(cx);
1513
1514        for (path, ids) in grouped.into_iter() {
1515            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1516                continue;
1517            };
1518
1519            let ids_to_expand = HashSet::from_iter(ids);
1520            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1521                let excerpt = snapshot.excerpt(*excerpt_id)?;
1522
1523                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1524                if ids_to_expand.contains(excerpt_id) {
1525                    match direction {
1526                        ExpandExcerptDirection::Up => {
1527                            context.start.row = context.start.row.saturating_sub(line_count);
1528                            context.start.column = 0;
1529                        }
1530                        ExpandExcerptDirection::Down => {
1531                            context.end.row =
1532                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1533                            context.end.column = excerpt.buffer.line_len(context.end.row);
1534                        }
1535                        ExpandExcerptDirection::UpAndDown => {
1536                            context.start.row = context.start.row.saturating_sub(line_count);
1537                            context.start.column = 0;
1538                            context.end.row =
1539                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1540                            context.end.column = excerpt.buffer.line_len(context.end.row);
1541                        }
1542                    }
1543                }
1544
1545                Some(ExcerptRange {
1546                    context,
1547                    primary: excerpt
1548                        .range
1549                        .primary
1550                        .as_ref()
1551                        .map(|range| range.to_point(&excerpt.buffer)),
1552                })
1553            });
1554            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1555            for range in expanded_ranges {
1556                if let Some(last_range) = merged_ranges.last_mut() {
1557                    if last_range.context.end >= range.context.start {
1558                        last_range.context.end = range.context.end;
1559                        continue;
1560                    }
1561                }
1562                merged_ranges.push(range)
1563            }
1564            let Some(excerpt_id) = excerpt_ids.first() else {
1565                continue;
1566            };
1567            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1568                continue;
1569            };
1570
1571            let Some(buffer) = self
1572                .buffers
1573                .borrow()
1574                .get(buffer_id)
1575                .map(|b| b.buffer.clone())
1576            else {
1577                continue;
1578            };
1579
1580            let buffer_snapshot = buffer.read(cx).snapshot();
1581            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1582        }
1583    }
1584
1585    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1586    pub fn set_excerpts_for_path(
1587        &mut self,
1588        path: PathKey,
1589        buffer: Entity<Buffer>,
1590        ranges: Vec<Range<Point>>,
1591        context_line_count: u32,
1592        cx: &mut Context<Self>,
1593    ) -> bool {
1594        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1595
1596        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1597        self.update_path_excerpts(path, buffer, &buffer_snapshot, new, cx)
1598    }
1599
1600    fn update_path_excerpts(
1601        &mut self,
1602        path: PathKey,
1603        buffer: Entity<Buffer>,
1604        buffer_snapshot: &BufferSnapshot,
1605        new: Vec<ExcerptRange<Point>>,
1606        cx: &mut Context<Self>,
1607    ) -> bool {
1608        let mut insert_after = self
1609            .excerpts_by_path
1610            .range(..path.clone())
1611            .next_back()
1612            .map(|(_, value)| *value.last().unwrap())
1613            .unwrap_or(ExcerptId::min());
1614
1615        let existing = self
1616            .excerpts_by_path
1617            .get(&path)
1618            .cloned()
1619            .unwrap_or_default();
1620
1621        let mut new_iter = new.into_iter().peekable();
1622        let mut existing_iter = existing.into_iter().peekable();
1623
1624        let mut new_excerpt_ids = Vec::new();
1625        let mut to_remove = Vec::new();
1626        let mut to_insert = Vec::new();
1627        let mut added_a_new_excerpt = false;
1628        let snapshot = self.snapshot(cx);
1629
1630        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1631        excerpts_cursor.next(&());
1632
1633        loop {
1634            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1635                (Some(new), Some(existing)) => (new, existing),
1636                (None, None) => break,
1637                (None, Some(_)) => {
1638                    to_remove.push(existing_iter.next().unwrap());
1639                    continue;
1640                }
1641                (Some(_), None) => {
1642                    added_a_new_excerpt = true;
1643                    to_insert.push(new_iter.next().unwrap());
1644                    continue;
1645                }
1646            };
1647            let locator = snapshot.excerpt_locator_for_id(*existing);
1648            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1649            let existing_excerpt = excerpts_cursor.item().unwrap();
1650            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1651                to_remove.push(existing_iter.next().unwrap());
1652                to_insert.push(new_iter.next().unwrap());
1653                continue;
1654            }
1655
1656            let existing_start = existing_excerpt
1657                .range
1658                .context
1659                .start
1660                .to_point(&buffer_snapshot);
1661            let existing_end = existing_excerpt
1662                .range
1663                .context
1664                .end
1665                .to_point(&buffer_snapshot);
1666
1667            if existing_end < new.context.start {
1668                to_remove.push(existing_iter.next().unwrap());
1669                continue;
1670            } else if existing_start > new.context.end {
1671                to_insert.push(new_iter.next().unwrap());
1672                continue;
1673            }
1674
1675            // maybe merge overlapping excerpts?
1676            // it's hard to distinguish between a manually expanded excerpt, and one that
1677            // got smaller because of a missing diff.
1678            if existing_start == new.context.start && existing_end == new.context.end {
1679                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1680                    insert_after,
1681                    buffer.clone(),
1682                    mem::take(&mut to_insert),
1683                    cx,
1684                ));
1685                insert_after = existing_iter.next().unwrap();
1686                new_excerpt_ids.push(insert_after);
1687                new_iter.next();
1688            } else {
1689                to_remove.push(existing_iter.next().unwrap());
1690                to_insert.push(new_iter.next().unwrap());
1691            }
1692        }
1693
1694        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1695            insert_after,
1696            buffer,
1697            to_insert,
1698            cx,
1699        ));
1700        self.remove_excerpts(to_remove, cx);
1701        if new_excerpt_ids.is_empty() {
1702            self.excerpts_by_path.remove(&path);
1703        } else {
1704            for excerpt_id in &new_excerpt_ids {
1705                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1706            }
1707            self.excerpts_by_path.insert(path, new_excerpt_ids);
1708        }
1709
1710        added_a_new_excerpt
1711    }
1712
1713    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1714        self.excerpts_by_path.keys().cloned()
1715    }
1716
1717    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1718        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1719            self.remove_excerpts(to_remove, cx)
1720        }
1721    }
1722
1723    pub fn push_multiple_excerpts_with_context_lines(
1724        &self,
1725        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1726        context_line_count: u32,
1727        cx: &mut Context<Self>,
1728    ) -> Task<Vec<Range<Anchor>>> {
1729        use futures::StreamExt;
1730
1731        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1732
1733        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1734
1735        for (buffer, ranges) in buffers_with_ranges {
1736            let (buffer_id, buffer_snapshot) =
1737                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1738
1739            buffer_ids.push(buffer_id);
1740
1741            cx.background_spawn({
1742                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1743
1744                async move {
1745                    let (excerpt_ranges, counts) =
1746                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1747                    excerpt_ranges_tx
1748                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1749                        .await
1750                        .ok();
1751                }
1752            })
1753            .detach()
1754        }
1755
1756        cx.spawn(move |this, mut cx| async move {
1757            let mut results_by_buffer_id = HashMap::default();
1758            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1759                excerpt_ranges_rx.next().await
1760            {
1761                results_by_buffer_id
1762                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1763            }
1764
1765            let mut multi_buffer_ranges = Vec::default();
1766            'outer: for buffer_id in buffer_ids {
1767                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1768                    results_by_buffer_id.remove(&buffer_id)
1769                else {
1770                    continue;
1771                };
1772
1773                let mut ranges = ranges.into_iter();
1774                let mut range_counts = range_counts.into_iter();
1775                for excerpt_ranges in excerpt_ranges.chunks(100) {
1776                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1777                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1778                    }) {
1779                        Ok(excerpt_ids) => excerpt_ids,
1780                        Err(_) => continue 'outer,
1781                    };
1782
1783                    for (excerpt_id, range_count) in
1784                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1785                    {
1786                        for range in ranges.by_ref().take(range_count) {
1787                            let start = Anchor {
1788                                buffer_id: Some(buffer_id),
1789                                excerpt_id,
1790                                text_anchor: range.start,
1791                                diff_base_anchor: None,
1792                            };
1793                            let end = Anchor {
1794                                buffer_id: Some(buffer_id),
1795                                excerpt_id,
1796                                text_anchor: range.end,
1797                                diff_base_anchor: None,
1798                            };
1799                            multi_buffer_ranges.push(start..end);
1800                        }
1801                    }
1802                }
1803            }
1804
1805            multi_buffer_ranges
1806        })
1807    }
1808
1809    pub fn insert_excerpts_after<O>(
1810        &mut self,
1811        prev_excerpt_id: ExcerptId,
1812        buffer: Entity<Buffer>,
1813        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1814        cx: &mut Context<Self>,
1815    ) -> Vec<ExcerptId>
1816    where
1817        O: text::ToOffset,
1818    {
1819        let mut ids = Vec::new();
1820        let mut next_excerpt_id =
1821            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1822                last_entry.id.0 + 1
1823            } else {
1824                1
1825            };
1826        self.insert_excerpts_with_ids_after(
1827            prev_excerpt_id,
1828            buffer,
1829            ranges.into_iter().map(|range| {
1830                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1831                ids.push(id);
1832                (id, range)
1833            }),
1834            cx,
1835        );
1836        ids
1837    }
1838
1839    pub fn insert_excerpts_with_ids_after<O>(
1840        &mut self,
1841        prev_excerpt_id: ExcerptId,
1842        buffer: Entity<Buffer>,
1843        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1844        cx: &mut Context<Self>,
1845    ) where
1846        O: text::ToOffset,
1847    {
1848        assert_eq!(self.history.transaction_depth, 0);
1849        let mut ranges = ranges.into_iter().peekable();
1850        if ranges.peek().is_none() {
1851            return Default::default();
1852        }
1853
1854        self.sync(cx);
1855
1856        let buffer_snapshot = buffer.read(cx).snapshot();
1857        let buffer_id = buffer_snapshot.remote_id();
1858
1859        let mut buffers = self.buffers.borrow_mut();
1860        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1861            self.buffer_changed_since_sync.replace(true);
1862            buffer.update(cx, |buffer, _| {
1863                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1864            });
1865            BufferState {
1866                last_version: buffer_snapshot.version().clone(),
1867                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1868                excerpts: Default::default(),
1869                _subscriptions: [
1870                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1871                    cx.subscribe(&buffer, Self::on_buffer_event),
1872                ],
1873                buffer: buffer.clone(),
1874            }
1875        });
1876
1877        let mut snapshot = self.snapshot.borrow_mut();
1878
1879        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1880        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1881        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1882        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1883        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1884
1885        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1886        new_excerpts.update_last(
1887            |excerpt| {
1888                excerpt.has_trailing_newline = true;
1889            },
1890            &(),
1891        );
1892
1893        let next_locator = if let Some(excerpt) = cursor.item() {
1894            excerpt.locator.clone()
1895        } else {
1896            Locator::max()
1897        };
1898
1899        let mut excerpts = Vec::new();
1900        while let Some((id, range)) = ranges.next() {
1901            let locator = Locator::between(&prev_locator, &next_locator);
1902            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1903                buffer_state.excerpts.insert(ix, locator.clone());
1904            }
1905            let range = ExcerptRange {
1906                context: buffer_snapshot.anchor_before(&range.context.start)
1907                    ..buffer_snapshot.anchor_after(&range.context.end),
1908                primary: range.primary.map(|primary| {
1909                    buffer_snapshot.anchor_before(&primary.start)
1910                        ..buffer_snapshot.anchor_after(&primary.end)
1911                }),
1912            };
1913            excerpts.push((id, range.clone()));
1914            let excerpt = Excerpt::new(
1915                id,
1916                locator.clone(),
1917                buffer_id,
1918                buffer_snapshot.clone(),
1919                range,
1920                ranges.peek().is_some() || cursor.item().is_some(),
1921            );
1922            new_excerpts.push(excerpt, &());
1923            prev_locator = locator.clone();
1924
1925            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1926                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1927            }
1928            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1929        }
1930
1931        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1932
1933        let suffix = cursor.suffix(&());
1934        let changed_trailing_excerpt = suffix.is_empty();
1935        new_excerpts.append(suffix, &());
1936        drop(cursor);
1937        snapshot.excerpts = new_excerpts;
1938        snapshot.excerpt_ids = new_excerpt_ids;
1939        if changed_trailing_excerpt {
1940            snapshot.trailing_excerpt_update_count += 1;
1941        }
1942
1943        self.sync_diff_transforms(
1944            &mut snapshot,
1945            vec![Edit {
1946                old: edit_start..edit_start,
1947                new: edit_start..edit_end,
1948            }],
1949            DiffChangeKind::BufferEdited,
1950        );
1951        cx.emit(Event::Edited {
1952            singleton_buffer_edited: false,
1953            edited_buffer: None,
1954        });
1955        cx.emit(Event::ExcerptsAdded {
1956            buffer,
1957            predecessor: prev_excerpt_id,
1958            excerpts,
1959        });
1960        cx.notify();
1961    }
1962
1963    pub fn clear(&mut self, cx: &mut Context<Self>) {
1964        self.sync(cx);
1965        let ids = self.excerpt_ids();
1966        self.buffers.borrow_mut().clear();
1967        let mut snapshot = self.snapshot.borrow_mut();
1968        let start = ExcerptOffset::new(0);
1969        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1970        snapshot.excerpts = Default::default();
1971        snapshot.trailing_excerpt_update_count += 1;
1972        snapshot.is_dirty = false;
1973        snapshot.has_deleted_file = false;
1974        snapshot.has_conflict = false;
1975
1976        self.sync_diff_transforms(
1977            &mut snapshot,
1978            vec![Edit {
1979                old: start..prev_len,
1980                new: start..start,
1981            }],
1982            DiffChangeKind::BufferEdited,
1983        );
1984        cx.emit(Event::Edited {
1985            singleton_buffer_edited: false,
1986            edited_buffer: None,
1987        });
1988        cx.emit(Event::ExcerptsRemoved { ids });
1989        cx.notify();
1990    }
1991
1992    pub fn excerpts_for_buffer(
1993        &self,
1994        buffer_id: BufferId,
1995        cx: &App,
1996    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1997        let mut excerpts = Vec::new();
1998        let snapshot = self.read(cx);
1999        let buffers = self.buffers.borrow();
2000        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2001        for locator in buffers
2002            .get(&buffer_id)
2003            .map(|state| &state.excerpts)
2004            .into_iter()
2005            .flatten()
2006        {
2007            cursor.seek_forward(&Some(locator), Bias::Left, &());
2008            if let Some(excerpt) = cursor.item() {
2009                if excerpt.locator == *locator {
2010                    excerpts.push((excerpt.id, excerpt.range.clone()));
2011                }
2012            }
2013        }
2014
2015        excerpts
2016    }
2017
2018    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2019        let snapshot = self.read(cx);
2020        let buffers = self.buffers.borrow();
2021        let mut excerpts = snapshot
2022            .excerpts
2023            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
2024        let mut diff_transforms = snapshot
2025            .diff_transforms
2026            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
2027        diff_transforms.next(&());
2028        let locators = buffers
2029            .get(&buffer_id)
2030            .into_iter()
2031            .flat_map(|state| &state.excerpts);
2032        let mut result = Vec::new();
2033        for locator in locators {
2034            excerpts.seek_forward(&Some(locator), Bias::Left, &());
2035            if let Some(excerpt) = excerpts.item() {
2036                if excerpt.locator == *locator {
2037                    let excerpt_start = excerpts.start().1.clone();
2038                    let excerpt_end =
2039                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2040
2041                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
2042                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
2043                    let start = diff_transforms.start().1 .0 + overshoot;
2044
2045                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
2046                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
2047                    let end = diff_transforms.start().1 .0 + overshoot;
2048
2049                    result.push(start..end)
2050                }
2051            }
2052        }
2053        result
2054    }
2055
2056    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2057        self.snapshot
2058            .borrow()
2059            .excerpts
2060            .iter()
2061            .map(|entry| entry.buffer_id)
2062            .collect()
2063    }
2064
2065    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2066        self.snapshot
2067            .borrow()
2068            .excerpts
2069            .iter()
2070            .map(|entry| entry.id)
2071            .collect()
2072    }
2073
2074    pub fn excerpt_containing(
2075        &self,
2076        position: impl ToOffset,
2077        cx: &App,
2078    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2079        let snapshot = self.read(cx);
2080        let offset = position.to_offset(&snapshot);
2081
2082        let mut cursor = snapshot.cursor::<usize>();
2083        cursor.seek(&offset);
2084        cursor
2085            .excerpt()
2086            .or_else(|| snapshot.excerpts.last())
2087            .map(|excerpt| {
2088                (
2089                    excerpt.id,
2090                    self.buffers
2091                        .borrow()
2092                        .get(&excerpt.buffer_id)
2093                        .unwrap()
2094                        .buffer
2095                        .clone(),
2096                    excerpt.range.context.clone(),
2097                )
2098            })
2099    }
2100
2101    // If point is at the end of the buffer, the last excerpt is returned
2102    pub fn point_to_buffer_offset<T: ToOffset>(
2103        &self,
2104        point: T,
2105        cx: &App,
2106    ) -> Option<(Entity<Buffer>, usize)> {
2107        let snapshot = self.read(cx);
2108        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2109        Some((
2110            self.buffers
2111                .borrow()
2112                .get(&buffer.remote_id())?
2113                .buffer
2114                .clone(),
2115            offset,
2116        ))
2117    }
2118
2119    // If point is at the end of the buffer, the last excerpt is returned
2120    pub fn point_to_buffer_point<T: ToPoint>(
2121        &self,
2122        point: T,
2123        cx: &App,
2124    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2125        let snapshot = self.read(cx);
2126        let (buffer, point, is_main_buffer) =
2127            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2128        Some((
2129            self.buffers
2130                .borrow()
2131                .get(&buffer.remote_id())?
2132                .buffer
2133                .clone(),
2134            point,
2135            is_main_buffer,
2136        ))
2137    }
2138
2139    pub fn buffer_point_to_anchor(
2140        &self,
2141        buffer: &Entity<Buffer>,
2142        point: Point,
2143        cx: &App,
2144    ) -> Option<Anchor> {
2145        let mut found = None;
2146        let snapshot = buffer.read(cx).snapshot();
2147        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2148            let start = range.context.start.to_point(&snapshot);
2149            let end = range.context.end.to_point(&snapshot);
2150            if start <= point && point < end {
2151                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2152                break;
2153            }
2154            if point < start {
2155                found = Some((start, excerpt_id));
2156            }
2157            if point > end {
2158                found = Some((end, excerpt_id));
2159            }
2160        }
2161
2162        found.map(|(point, excerpt_id)| {
2163            let text_anchor = snapshot.anchor_after(point);
2164            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2165        })
2166    }
2167
2168    pub fn remove_excerpts(
2169        &mut self,
2170        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2171        cx: &mut Context<Self>,
2172    ) {
2173        self.sync(cx);
2174        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2175        if ids.is_empty() {
2176            return;
2177        }
2178
2179        let mut buffers = self.buffers.borrow_mut();
2180        let mut snapshot = self.snapshot.borrow_mut();
2181        let mut new_excerpts = SumTree::default();
2182        let mut cursor = snapshot
2183            .excerpts
2184            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2185        let mut edits = Vec::new();
2186        let mut excerpt_ids = ids.iter().copied().peekable();
2187        let mut removed_buffer_ids = Vec::new();
2188
2189        while let Some(excerpt_id) = excerpt_ids.next() {
2190            self.paths_by_excerpt.remove(&excerpt_id);
2191            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2192            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2193            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2194
2195            if let Some(mut excerpt) = cursor.item() {
2196                if excerpt.id != excerpt_id {
2197                    continue;
2198                }
2199                let mut old_start = cursor.start().1;
2200
2201                // Skip over the removed excerpt.
2202                'remove_excerpts: loop {
2203                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2204                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2205                        if buffer_state.excerpts.is_empty() {
2206                            log::debug!(
2207                                "removing buffer and diff for buffer {}",
2208                                excerpt.buffer_id
2209                            );
2210                            buffers.remove(&excerpt.buffer_id);
2211                            removed_buffer_ids.push(excerpt.buffer_id);
2212                        }
2213                    }
2214                    cursor.next(&());
2215
2216                    // Skip over any subsequent excerpts that are also removed.
2217                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2218                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2219                        if let Some(next_excerpt) = cursor.item() {
2220                            if next_excerpt.locator == *next_locator {
2221                                excerpt_ids.next();
2222                                excerpt = next_excerpt;
2223                                continue 'remove_excerpts;
2224                            }
2225                        }
2226                    }
2227
2228                    break;
2229                }
2230
2231                // When removing the last excerpt, remove the trailing newline from
2232                // the previous excerpt.
2233                if cursor.item().is_none() && old_start.value > 0 {
2234                    old_start.value -= 1;
2235                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2236                }
2237
2238                // Push an edit for the removal of this run of excerpts.
2239                let old_end = cursor.start().1;
2240                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2241                edits.push(Edit {
2242                    old: old_start..old_end,
2243                    new: new_start..new_start,
2244                });
2245            }
2246        }
2247        let suffix = cursor.suffix(&());
2248        let changed_trailing_excerpt = suffix.is_empty();
2249        new_excerpts.append(suffix, &());
2250        drop(cursor);
2251        snapshot.excerpts = new_excerpts;
2252        for buffer_id in removed_buffer_ids {
2253            self.diffs.remove(&buffer_id);
2254            snapshot.diffs.remove(&buffer_id);
2255        }
2256
2257        if changed_trailing_excerpt {
2258            snapshot.trailing_excerpt_update_count += 1;
2259        }
2260
2261        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2262        self.buffer_changed_since_sync.replace(true);
2263        cx.emit(Event::Edited {
2264            singleton_buffer_edited: false,
2265            edited_buffer: None,
2266        });
2267        cx.emit(Event::ExcerptsRemoved { ids });
2268        cx.notify();
2269    }
2270
2271    pub fn wait_for_anchors<'a>(
2272        &self,
2273        anchors: impl 'a + Iterator<Item = Anchor>,
2274        cx: &mut Context<Self>,
2275    ) -> impl 'static + Future<Output = Result<()>> {
2276        let borrow = self.buffers.borrow();
2277        let mut error = None;
2278        let mut futures = Vec::new();
2279        for anchor in anchors {
2280            if let Some(buffer_id) = anchor.buffer_id {
2281                if let Some(buffer) = borrow.get(&buffer_id) {
2282                    buffer.buffer.update(cx, |buffer, _| {
2283                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2284                    });
2285                } else {
2286                    error = Some(anyhow!(
2287                        "buffer {buffer_id} is not part of this multi-buffer"
2288                    ));
2289                    break;
2290                }
2291            }
2292        }
2293        async move {
2294            if let Some(error) = error {
2295                Err(error)?;
2296            }
2297            for future in futures {
2298                future.await?;
2299            }
2300            Ok(())
2301        }
2302    }
2303
2304    pub fn text_anchor_for_position<T: ToOffset>(
2305        &self,
2306        position: T,
2307        cx: &App,
2308    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2309        let snapshot = self.read(cx);
2310        let anchor = snapshot.anchor_before(position);
2311        let buffer = self
2312            .buffers
2313            .borrow()
2314            .get(&anchor.buffer_id?)?
2315            .buffer
2316            .clone();
2317        Some((buffer, anchor.text_anchor))
2318    }
2319
2320    fn on_buffer_event(
2321        &mut self,
2322        buffer: Entity<Buffer>,
2323        event: &language::BufferEvent,
2324        cx: &mut Context<Self>,
2325    ) {
2326        cx.emit(match event {
2327            language::BufferEvent::Edited => Event::Edited {
2328                singleton_buffer_edited: true,
2329                edited_buffer: Some(buffer.clone()),
2330            },
2331            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2332            language::BufferEvent::Saved => Event::Saved,
2333            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2334            language::BufferEvent::Reloaded => Event::Reloaded,
2335            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2336            language::BufferEvent::LanguageChanged => {
2337                Event::LanguageChanged(buffer.read(cx).remote_id())
2338            }
2339            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2340            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2341            language::BufferEvent::Closed => Event::Closed,
2342            language::BufferEvent::Discarded => Event::Discarded,
2343            language::BufferEvent::CapabilityChanged => {
2344                self.capability = buffer.read(cx).capability();
2345                Event::CapabilityChanged
2346            }
2347            language::BufferEvent::Operation { .. } => return,
2348        });
2349    }
2350
2351    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2352        self.sync(cx);
2353        let mut snapshot = self.snapshot.borrow_mut();
2354        let diff = diff.read(cx);
2355        let buffer_id = diff.buffer_id;
2356        let diff = diff.snapshot(cx);
2357        snapshot.diffs.insert(buffer_id, diff);
2358    }
2359
2360    fn buffer_diff_changed(
2361        &mut self,
2362        diff: Entity<BufferDiff>,
2363        range: Range<text::Anchor>,
2364        cx: &mut Context<Self>,
2365    ) {
2366        self.sync(cx);
2367        self.buffer_changed_since_sync.replace(true);
2368
2369        let diff = diff.read(cx);
2370        let buffer_id = diff.buffer_id;
2371        let buffers = self.buffers.borrow();
2372        let Some(buffer_state) = buffers.get(&buffer_id) else {
2373            return;
2374        };
2375
2376        let buffer = buffer_state.buffer.read(cx);
2377        let diff_change_range = range.to_offset(buffer);
2378
2379        let new_diff = diff.snapshot(cx);
2380        let mut snapshot = self.snapshot.borrow_mut();
2381        let base_text_changed = snapshot
2382            .diffs
2383            .get(&buffer_id)
2384            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2385
2386        snapshot.diffs.insert(buffer_id, new_diff);
2387
2388        let mut excerpt_edits = Vec::new();
2389        for locator in &buffer_state.excerpts {
2390            let mut cursor = snapshot
2391                .excerpts
2392                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2393            cursor.seek_forward(&Some(locator), Bias::Left, &());
2394            if let Some(excerpt) = cursor.item() {
2395                if excerpt.locator == *locator {
2396                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2397                    if diff_change_range.end < excerpt_buffer_range.start
2398                        || diff_change_range.start > excerpt_buffer_range.end
2399                    {
2400                        continue;
2401                    }
2402                    let excerpt_start = cursor.start().1;
2403                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2404                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2405                        diff_change_range
2406                            .start
2407                            .saturating_sub(excerpt_buffer_range.start),
2408                    );
2409                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2410                        diff_change_range
2411                            .end
2412                            .saturating_sub(excerpt_buffer_range.start),
2413                    );
2414                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2415                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2416                    excerpt_edits.push(Edit {
2417                        old: edit_start..edit_end,
2418                        new: edit_start..edit_end,
2419                    });
2420                }
2421            }
2422        }
2423
2424        self.sync_diff_transforms(
2425            &mut snapshot,
2426            excerpt_edits,
2427            DiffChangeKind::DiffUpdated {
2428                base_changed: base_text_changed,
2429            },
2430        );
2431        cx.emit(Event::Edited {
2432            singleton_buffer_edited: false,
2433            edited_buffer: None,
2434        });
2435    }
2436
2437    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2438        self.buffers
2439            .borrow()
2440            .values()
2441            .map(|state| state.buffer.clone())
2442            .collect()
2443    }
2444
2445    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2446        self.buffers
2447            .borrow()
2448            .get(&buffer_id)
2449            .map(|state| state.buffer.clone())
2450    }
2451
2452    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2453        self.point_to_buffer_offset(point, cx)
2454            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2455    }
2456
2457    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2458        let buffer_id = self
2459            .snapshot
2460            .borrow()
2461            .excerpts
2462            .first()
2463            .map(|excerpt| excerpt.buffer.remote_id());
2464        buffer_id
2465            .and_then(|buffer_id| self.buffer(buffer_id))
2466            .map(|buffer| {
2467                let buffer = buffer.read(cx);
2468                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2469            })
2470            .unwrap_or_else(move || self.language_settings_at(0, cx))
2471    }
2472
2473    pub fn language_settings_at<'a, T: ToOffset>(
2474        &'a self,
2475        point: T,
2476        cx: &'a App,
2477    ) -> Cow<'a, LanguageSettings> {
2478        let mut language = None;
2479        let mut file = None;
2480        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2481            let buffer = buffer.read(cx);
2482            language = buffer.language_at(offset);
2483            file = buffer.file();
2484        }
2485        language_settings(language.map(|l| l.name()), file, cx)
2486    }
2487
2488    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2489        self.buffers
2490            .borrow()
2491            .values()
2492            .for_each(|state| f(&state.buffer))
2493    }
2494
2495    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2496        if let Some(title) = self.title.as_ref() {
2497            return title.into();
2498        }
2499
2500        if let Some(buffer) = self.as_singleton() {
2501            if let Some(file) = buffer.read(cx).file() {
2502                return file.file_name(cx).to_string_lossy();
2503            }
2504        }
2505
2506        "untitled".into()
2507    }
2508
2509    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2510        self.title = Some(title);
2511        cx.notify();
2512    }
2513
2514    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2515    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2516        for buffer_state in self.buffers.borrow().values() {
2517            buffer_state
2518                .buffer
2519                .update(cx, |buffer, _cx| buffer.refresh_preview());
2520        }
2521    }
2522
2523    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2524    pub fn preserve_preview(&self, cx: &App) -> bool {
2525        self.buffers
2526            .borrow()
2527            .values()
2528            .all(|state| state.buffer.read(cx).preserve_preview())
2529    }
2530
2531    #[cfg(any(test, feature = "test-support"))]
2532    pub fn is_parsing(&self, cx: &App) -> bool {
2533        self.as_singleton().unwrap().read(cx).is_parsing()
2534    }
2535
2536    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2537        let buffer_id = diff.read(cx).buffer_id;
2538        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2539        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2540    }
2541
2542    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2543        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2544    }
2545
2546    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2547        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2548    }
2549
2550    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2551        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2552    }
2553
2554    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2555        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2556        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2557    }
2558
2559    pub fn all_diff_hunks_expanded(&self) -> bool {
2560        self.snapshot.borrow().all_diff_hunks_expanded
2561    }
2562
2563    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2564        self.read(cx)
2565            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2566            .nth(1)
2567            .is_some()
2568    }
2569
2570    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2571        let snapshot = self.read(cx);
2572        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2573        let offset_range = range.to_offset(&snapshot);
2574        cursor.seek(&offset_range.start, Bias::Left, &());
2575        while let Some(item) = cursor.item() {
2576            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2577                break;
2578            }
2579            if item.hunk_info().is_some() {
2580                return true;
2581            }
2582            cursor.next(&());
2583        }
2584        false
2585    }
2586
2587    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2588        let snapshot = self.read(cx);
2589        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2590        for range in ranges {
2591            let range = range.to_point(&snapshot);
2592            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2593            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2594            let start = start.saturating_sub(1);
2595            let end = snapshot.len().min(end + 1);
2596            cursor.seek(&start, Bias::Right, &());
2597            while let Some(item) = cursor.item() {
2598                if *cursor.start() >= end {
2599                    break;
2600                }
2601                if item.hunk_info().is_some() {
2602                    return true;
2603                }
2604                cursor.next(&());
2605            }
2606        }
2607        false
2608    }
2609
2610    pub fn expand_or_collapse_diff_hunks_inner(
2611        &mut self,
2612        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2613        expand: bool,
2614        cx: &mut Context<Self>,
2615    ) {
2616        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2617            return;
2618        }
2619        self.sync(cx);
2620        let mut snapshot = self.snapshot.borrow_mut();
2621        let mut excerpt_edits = Vec::new();
2622        for (range, end_excerpt_id) in ranges {
2623            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2624                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2625                    continue;
2626                }
2627                let start = Anchor::in_buffer(
2628                    diff_hunk.excerpt_id,
2629                    diff_hunk.buffer_id,
2630                    diff_hunk.buffer_range.start,
2631                );
2632                let end = Anchor::in_buffer(
2633                    diff_hunk.excerpt_id,
2634                    diff_hunk.buffer_id,
2635                    diff_hunk.buffer_range.end,
2636                );
2637                let start = snapshot.excerpt_offset_for_anchor(&start);
2638                let end = snapshot.excerpt_offset_for_anchor(&end);
2639                excerpt_edits.push(text::Edit {
2640                    old: start..end,
2641                    new: start..end,
2642                });
2643            }
2644        }
2645
2646        self.sync_diff_transforms(
2647            &mut snapshot,
2648            excerpt_edits,
2649            DiffChangeKind::ExpandOrCollapseHunks { expand },
2650        );
2651        cx.emit(Event::DiffHunksToggled);
2652        cx.emit(Event::Edited {
2653            singleton_buffer_edited: false,
2654            edited_buffer: None,
2655        });
2656    }
2657
2658    pub fn expand_or_collapse_diff_hunks(
2659        &mut self,
2660        ranges: Vec<Range<Anchor>>,
2661        expand: bool,
2662        cx: &mut Context<Self>,
2663    ) {
2664        let snapshot = self.snapshot.borrow().clone();
2665        let ranges = ranges.iter().map(move |range| {
2666            let end_excerpt_id = range.end.excerpt_id;
2667            let range = range.to_point(&snapshot);
2668            let mut peek_end = range.end;
2669            if range.end.row < snapshot.max_row().0 {
2670                peek_end = Point::new(range.end.row + 1, 0);
2671            };
2672            (range.start..peek_end, end_excerpt_id)
2673        });
2674        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2675    }
2676
2677    pub fn resize_excerpt(
2678        &mut self,
2679        id: ExcerptId,
2680        range: Range<text::Anchor>,
2681        cx: &mut Context<Self>,
2682    ) {
2683        self.sync(cx);
2684
2685        let mut snapshot = self.snapshot.borrow_mut();
2686        let locator = snapshot.excerpt_locator_for_id(id);
2687        let mut new_excerpts = SumTree::default();
2688        let mut cursor = snapshot
2689            .excerpts
2690            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2691        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2692
2693        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2694        new_excerpts.append(prefix, &());
2695
2696        let mut excerpt = cursor.item().unwrap().clone();
2697        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2698
2699        excerpt.range.context.start = range.start;
2700        excerpt.range.context.end = range.end;
2701        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2702
2703        excerpt.text_summary = excerpt
2704            .buffer
2705            .text_summary_for_range(excerpt.range.context.clone());
2706
2707        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2708        let old_start_offset = cursor.start().1;
2709        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2710        let edit = Edit {
2711            old: old_start_offset..old_start_offset + old_text_len,
2712            new: new_start_offset..new_start_offset + new_text_len,
2713        };
2714
2715        if let Some(last_edit) = edits.last_mut() {
2716            if last_edit.old.end == edit.old.start {
2717                last_edit.old.end = edit.old.end;
2718                last_edit.new.end = edit.new.end;
2719            } else {
2720                edits.push(edit);
2721            }
2722        } else {
2723            edits.push(edit);
2724        }
2725
2726        new_excerpts.push(excerpt, &());
2727
2728        cursor.next(&());
2729
2730        new_excerpts.append(cursor.suffix(&()), &());
2731
2732        drop(cursor);
2733        snapshot.excerpts = new_excerpts;
2734
2735        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2736        cx.emit(Event::Edited {
2737            singleton_buffer_edited: false,
2738            edited_buffer: None,
2739        });
2740        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2741        cx.notify();
2742    }
2743
2744    pub fn expand_excerpts(
2745        &mut self,
2746        ids: impl IntoIterator<Item = ExcerptId>,
2747        line_count: u32,
2748        direction: ExpandExcerptDirection,
2749        cx: &mut Context<Self>,
2750    ) {
2751        if line_count == 0 {
2752            return;
2753        }
2754        self.sync(cx);
2755        if !self.excerpts_by_path.is_empty() {
2756            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2757            return;
2758        }
2759        let mut snapshot = self.snapshot.borrow_mut();
2760
2761        let ids = ids.into_iter().collect::<Vec<_>>();
2762        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2763        let mut new_excerpts = SumTree::default();
2764        let mut cursor = snapshot
2765            .excerpts
2766            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2767        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2768
2769        for locator in &locators {
2770            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2771            new_excerpts.append(prefix, &());
2772
2773            let mut excerpt = cursor.item().unwrap().clone();
2774            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2775
2776            let up_line_count = if direction.should_expand_up() {
2777                line_count
2778            } else {
2779                0
2780            };
2781
2782            let start_row = excerpt
2783                .range
2784                .context
2785                .start
2786                .to_point(&excerpt.buffer)
2787                .row
2788                .saturating_sub(up_line_count);
2789            let start_point = Point::new(start_row, 0);
2790            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2791
2792            let down_line_count = if direction.should_expand_down() {
2793                line_count
2794            } else {
2795                0
2796            };
2797
2798            let mut end_point = excerpt.buffer.clip_point(
2799                excerpt.range.context.end.to_point(&excerpt.buffer)
2800                    + Point::new(down_line_count, 0),
2801                Bias::Left,
2802            );
2803            end_point.column = excerpt.buffer.line_len(end_point.row);
2804            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2805            excerpt.max_buffer_row = end_point.row;
2806
2807            excerpt.text_summary = excerpt
2808                .buffer
2809                .text_summary_for_range(excerpt.range.context.clone());
2810
2811            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2812            let old_start_offset = cursor.start().1;
2813            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2814            let edit = Edit {
2815                old: old_start_offset..old_start_offset + old_text_len,
2816                new: new_start_offset..new_start_offset + new_text_len,
2817            };
2818
2819            if let Some(last_edit) = edits.last_mut() {
2820                if last_edit.old.end == edit.old.start {
2821                    last_edit.old.end = edit.old.end;
2822                    last_edit.new.end = edit.new.end;
2823                } else {
2824                    edits.push(edit);
2825                }
2826            } else {
2827                edits.push(edit);
2828            }
2829
2830            new_excerpts.push(excerpt, &());
2831
2832            cursor.next(&());
2833        }
2834
2835        new_excerpts.append(cursor.suffix(&()), &());
2836
2837        drop(cursor);
2838        snapshot.excerpts = new_excerpts;
2839
2840        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2841        cx.emit(Event::Edited {
2842            singleton_buffer_edited: false,
2843            edited_buffer: None,
2844        });
2845        cx.emit(Event::ExcerptsExpanded { ids });
2846        cx.notify();
2847    }
2848
2849    fn sync(&self, cx: &App) {
2850        let changed = self.buffer_changed_since_sync.replace(false);
2851        if !changed {
2852            return;
2853        }
2854
2855        let mut snapshot = self.snapshot.borrow_mut();
2856        let mut excerpts_to_edit = Vec::new();
2857        let mut non_text_state_updated = false;
2858        let mut is_dirty = false;
2859        let mut has_deleted_file = false;
2860        let mut has_conflict = false;
2861        let mut edited = false;
2862        let mut buffers = self.buffers.borrow_mut();
2863        for buffer_state in buffers.values_mut() {
2864            let buffer = buffer_state.buffer.read(cx);
2865            let version = buffer.version();
2866            let non_text_state_update_count = buffer.non_text_state_update_count();
2867
2868            let buffer_edited = version.changed_since(&buffer_state.last_version);
2869            let buffer_non_text_state_updated =
2870                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2871            if buffer_edited || buffer_non_text_state_updated {
2872                buffer_state.last_version = version;
2873                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2874                excerpts_to_edit.extend(
2875                    buffer_state
2876                        .excerpts
2877                        .iter()
2878                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2879                );
2880            }
2881
2882            edited |= buffer_edited;
2883            non_text_state_updated |= buffer_non_text_state_updated;
2884            is_dirty |= buffer.is_dirty();
2885            has_deleted_file |= buffer
2886                .file()
2887                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2888            has_conflict |= buffer.has_conflict();
2889        }
2890        if edited {
2891            snapshot.edit_count += 1;
2892        }
2893        if non_text_state_updated {
2894            snapshot.non_text_state_update_count += 1;
2895        }
2896        snapshot.is_dirty = is_dirty;
2897        snapshot.has_deleted_file = has_deleted_file;
2898        snapshot.has_conflict = has_conflict;
2899
2900        for (id, diff) in self.diffs.iter() {
2901            if snapshot.diffs.get(&id).is_none() {
2902                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2903            }
2904        }
2905
2906        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2907
2908        let mut edits = Vec::new();
2909        let mut new_excerpts = SumTree::default();
2910        let mut cursor = snapshot
2911            .excerpts
2912            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2913
2914        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2915            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2916            let old_excerpt = cursor.item().unwrap();
2917            let buffer = buffer.read(cx);
2918            let buffer_id = buffer.remote_id();
2919
2920            let mut new_excerpt;
2921            if buffer_edited {
2922                edits.extend(
2923                    buffer
2924                        .edits_since_in_range::<usize>(
2925                            old_excerpt.buffer.version(),
2926                            old_excerpt.range.context.clone(),
2927                        )
2928                        .map(|edit| {
2929                            let excerpt_old_start = cursor.start().1;
2930                            let excerpt_new_start =
2931                                ExcerptOffset::new(new_excerpts.summary().text.len);
2932                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2933                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2934                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2935                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2936                            Edit {
2937                                old: old_start..old_end,
2938                                new: new_start..new_end,
2939                            }
2940                        }),
2941                );
2942
2943                new_excerpt = Excerpt::new(
2944                    old_excerpt.id,
2945                    locator.clone(),
2946                    buffer_id,
2947                    buffer.snapshot(),
2948                    old_excerpt.range.clone(),
2949                    old_excerpt.has_trailing_newline,
2950                );
2951            } else {
2952                new_excerpt = old_excerpt.clone();
2953                new_excerpt.buffer = buffer.snapshot();
2954            }
2955
2956            new_excerpts.push(new_excerpt, &());
2957            cursor.next(&());
2958        }
2959        new_excerpts.append(cursor.suffix(&()), &());
2960
2961        drop(cursor);
2962        snapshot.excerpts = new_excerpts;
2963
2964        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2965    }
2966
2967    fn sync_diff_transforms(
2968        &self,
2969        snapshot: &mut MultiBufferSnapshot,
2970        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2971        change_kind: DiffChangeKind,
2972    ) {
2973        if excerpt_edits.is_empty() {
2974            return;
2975        }
2976
2977        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2978        let mut old_diff_transforms = snapshot
2979            .diff_transforms
2980            .cursor::<(ExcerptOffset, usize)>(&());
2981        let mut new_diff_transforms = SumTree::default();
2982        let mut old_expanded_hunks = HashSet::default();
2983        let mut output_edits = Vec::new();
2984        let mut output_delta = 0_isize;
2985        let mut at_transform_boundary = true;
2986        let mut end_of_current_insert = None;
2987
2988        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2989        while let Some(edit) = excerpt_edits.next() {
2990            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2991            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2992                excerpts.prev(&());
2993            }
2994
2995            // Keep any transforms that are before the edit.
2996            if at_transform_boundary {
2997                at_transform_boundary = false;
2998                let transforms_before_edit =
2999                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3000                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3001                if let Some(transform) = old_diff_transforms.item() {
3002                    if old_diff_transforms.end(&()).0 == edit.old.start
3003                        && old_diff_transforms.start().0 < edit.old.start
3004                    {
3005                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3006                        old_diff_transforms.next(&());
3007                    }
3008                }
3009            }
3010
3011            // Compute the start of the edit in output coordinates.
3012            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3013            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3014            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3015
3016            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3017                &edit,
3018                &mut excerpts,
3019                &mut old_diff_transforms,
3020                &mut new_diff_transforms,
3021                &mut end_of_current_insert,
3022                &mut old_expanded_hunks,
3023                &snapshot,
3024                change_kind,
3025            );
3026
3027            // Compute the end of the edit in output coordinates.
3028            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3029            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3030            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3031            let edit_new_end =
3032                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3033            let output_edit = Edit {
3034                old: edit_old_start..edit_old_end,
3035                new: edit_new_start..edit_new_end,
3036            };
3037
3038            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3039            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3040            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3041                output_edits.push(output_edit);
3042            }
3043
3044            // If this is the last edit that intersects the current diff transform,
3045            // then recreate the content up to the end of this transform, to prepare
3046            // for reusing additional slices of the old transforms.
3047            if excerpt_edits.peek().map_or(true, |next_edit| {
3048                next_edit.old.start >= old_diff_transforms.end(&()).0
3049            }) {
3050                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3051                    && match old_diff_transforms.item() {
3052                        Some(DiffTransform::BufferContent {
3053                            inserted_hunk_info: Some(hunk),
3054                            ..
3055                        }) => excerpts.item().is_some_and(|excerpt| {
3056                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3057                        }),
3058                        _ => true,
3059                    };
3060
3061                let mut excerpt_offset = edit.new.end;
3062                if !keep_next_old_transform {
3063                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3064                    old_diff_transforms.next(&());
3065                }
3066
3067                old_expanded_hunks.clear();
3068                self.push_buffer_content_transform(
3069                    &snapshot,
3070                    &mut new_diff_transforms,
3071                    excerpt_offset,
3072                    end_of_current_insert,
3073                );
3074                at_transform_boundary = true;
3075            }
3076        }
3077
3078        // Keep any transforms that are after the last edit.
3079        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3080
3081        // Ensure there's always at least one buffer content transform.
3082        if new_diff_transforms.is_empty() {
3083            new_diff_transforms.push(
3084                DiffTransform::BufferContent {
3085                    summary: Default::default(),
3086                    inserted_hunk_info: None,
3087                },
3088                &(),
3089            );
3090        }
3091
3092        self.subscriptions.publish(output_edits);
3093        drop(old_diff_transforms);
3094        drop(excerpts);
3095        snapshot.diff_transforms = new_diff_transforms;
3096        snapshot.edit_count += 1;
3097
3098        #[cfg(any(test, feature = "test-support"))]
3099        snapshot.check_invariants();
3100    }
3101
3102    fn recompute_diff_transforms_for_edit(
3103        &self,
3104        edit: &Edit<TypedOffset<Excerpt>>,
3105        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3106        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3107        new_diff_transforms: &mut SumTree<DiffTransform>,
3108        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3109        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3110        snapshot: &MultiBufferSnapshot,
3111        change_kind: DiffChangeKind,
3112    ) -> bool {
3113        log::trace!(
3114            "recomputing diff transform for edit {:?} => {:?}",
3115            edit.old.start.value..edit.old.end.value,
3116            edit.new.start.value..edit.new.end.value
3117        );
3118
3119        // Record which hunks were previously expanded.
3120        while let Some(item) = old_diff_transforms.item() {
3121            if let Some(hunk_info) = item.hunk_info() {
3122                log::trace!(
3123                    "previously expanded hunk at {}",
3124                    old_diff_transforms.start().0
3125                );
3126                old_expanded_hunks.insert(hunk_info);
3127            }
3128            if old_diff_transforms.end(&()).0 > edit.old.end {
3129                break;
3130            }
3131            old_diff_transforms.next(&());
3132        }
3133
3134        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3135        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3136        if old_expanded_hunks.is_empty()
3137            && change_kind == DiffChangeKind::BufferEdited
3138            && !all_diff_hunks_expanded
3139        {
3140            return false;
3141        }
3142
3143        // Visit each excerpt that intersects the edit.
3144        let mut did_expand_hunks = false;
3145        while let Some(excerpt) = excerpts.item() {
3146            // Recompute the expanded hunks in the portion of the excerpt that
3147            // intersects the edit.
3148            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3149                let buffer = &excerpt.buffer;
3150                let excerpt_start = *excerpts.start();
3151                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3152                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3153                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3154                let edit_buffer_start =
3155                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3156                let edit_buffer_end =
3157                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3158                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3159                let edit_anchor_range =
3160                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3161
3162                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3163                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3164                        continue;
3165                    }
3166
3167                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3168                    if hunk_buffer_range.start < excerpt_buffer_start {
3169                        log::trace!("skipping hunk that starts before excerpt");
3170                        continue;
3171                    }
3172
3173                    let hunk_info = DiffTransformHunkInfo {
3174                        excerpt_id: excerpt.id,
3175                        hunk_start_anchor: hunk.buffer_range.start,
3176                        hunk_secondary_status: hunk.secondary_status,
3177                    };
3178
3179                    let hunk_excerpt_start = excerpt_start
3180                        + ExcerptOffset::new(
3181                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3182                        );
3183                    let hunk_excerpt_end = excerpt_end.min(
3184                        excerpt_start
3185                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3186                    );
3187
3188                    self.push_buffer_content_transform(
3189                        snapshot,
3190                        new_diff_transforms,
3191                        hunk_excerpt_start,
3192                        *end_of_current_insert,
3193                    );
3194
3195                    // For every existing hunk, determine if it was previously expanded
3196                    // and if it should currently be expanded.
3197                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3198                    let should_expand_hunk = match &change_kind {
3199                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3200                            was_previously_expanded || all_diff_hunks_expanded
3201                        }
3202                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3203                            let intersects = hunk_buffer_range.is_empty()
3204                                || hunk_buffer_range.end > edit_buffer_start;
3205                            if *expand {
3206                                intersects || was_previously_expanded || all_diff_hunks_expanded
3207                            } else {
3208                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3209                            }
3210                        }
3211                        _ => was_previously_expanded || all_diff_hunks_expanded,
3212                    };
3213
3214                    if should_expand_hunk {
3215                        did_expand_hunks = true;
3216                        log::trace!(
3217                            "expanding hunk {:?}, excerpt:{:?}",
3218                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3219                            excerpt.id
3220                        );
3221
3222                        if !hunk.diff_base_byte_range.is_empty()
3223                            && hunk_buffer_range.start >= edit_buffer_start
3224                            && hunk_buffer_range.start <= excerpt_buffer_end
3225                        {
3226                            let base_text = diff.base_text();
3227                            let mut text_cursor =
3228                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3229                            let mut base_text_summary =
3230                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3231
3232                            let mut has_trailing_newline = false;
3233                            if base_text_summary.last_line_chars > 0 {
3234                                base_text_summary += TextSummary::newline();
3235                                has_trailing_newline = true;
3236                            }
3237
3238                            new_diff_transforms.push(
3239                                DiffTransform::DeletedHunk {
3240                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3241                                    summary: base_text_summary,
3242                                    buffer_id: excerpt.buffer_id,
3243                                    hunk_info,
3244                                    has_trailing_newline,
3245                                },
3246                                &(),
3247                            );
3248                        }
3249
3250                        if !hunk_buffer_range.is_empty() {
3251                            *end_of_current_insert =
3252                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3253                        }
3254                    }
3255                }
3256            }
3257
3258            if excerpts.end(&()) <= edit.new.end {
3259                excerpts.next(&());
3260            } else {
3261                break;
3262            }
3263        }
3264
3265        did_expand_hunks || !old_expanded_hunks.is_empty()
3266    }
3267
3268    fn append_diff_transforms(
3269        &self,
3270        new_transforms: &mut SumTree<DiffTransform>,
3271        subtree: SumTree<DiffTransform>,
3272    ) {
3273        if let Some(DiffTransform::BufferContent {
3274            inserted_hunk_info,
3275            summary,
3276        }) = subtree.first()
3277        {
3278            if self.extend_last_buffer_content_transform(
3279                new_transforms,
3280                *inserted_hunk_info,
3281                *summary,
3282            ) {
3283                let mut cursor = subtree.cursor::<()>(&());
3284                cursor.next(&());
3285                cursor.next(&());
3286                new_transforms.append(cursor.suffix(&()), &());
3287                return;
3288            }
3289        }
3290        new_transforms.append(subtree, &());
3291    }
3292
3293    fn push_diff_transform(
3294        &self,
3295        new_transforms: &mut SumTree<DiffTransform>,
3296        transform: DiffTransform,
3297    ) {
3298        if let DiffTransform::BufferContent {
3299            inserted_hunk_info: inserted_hunk_anchor,
3300            summary,
3301        } = transform
3302        {
3303            if self.extend_last_buffer_content_transform(
3304                new_transforms,
3305                inserted_hunk_anchor,
3306                summary,
3307            ) {
3308                return;
3309            }
3310        }
3311        new_transforms.push(transform, &());
3312    }
3313
3314    fn push_buffer_content_transform(
3315        &self,
3316        old_snapshot: &MultiBufferSnapshot,
3317        new_transforms: &mut SumTree<DiffTransform>,
3318        end_offset: ExcerptOffset,
3319        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3320    ) {
3321        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3322            (end_offset.min(insertion_end_offset), Some(hunk_info))
3323        });
3324        let unchanged_region = [(end_offset, None)];
3325
3326        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3327        {
3328            let start_offset = new_transforms.summary().excerpt_len();
3329            if end_offset <= start_offset {
3330                continue;
3331            }
3332            let summary_to_add = old_snapshot
3333                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3334
3335            if !self.extend_last_buffer_content_transform(
3336                new_transforms,
3337                inserted_hunk_info,
3338                summary_to_add,
3339            ) {
3340                new_transforms.push(
3341                    DiffTransform::BufferContent {
3342                        summary: summary_to_add,
3343                        inserted_hunk_info,
3344                    },
3345                    &(),
3346                )
3347            }
3348        }
3349    }
3350
3351    fn extend_last_buffer_content_transform(
3352        &self,
3353        new_transforms: &mut SumTree<DiffTransform>,
3354        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3355        summary_to_add: TextSummary,
3356    ) -> bool {
3357        let mut did_extend = false;
3358        new_transforms.update_last(
3359            |last_transform| {
3360                if let DiffTransform::BufferContent {
3361                    summary,
3362                    inserted_hunk_info: inserted_hunk_anchor,
3363                } = last_transform
3364                {
3365                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3366                        *summary += summary_to_add;
3367                        did_extend = true;
3368                    }
3369                }
3370            },
3371            &(),
3372        );
3373        did_extend
3374    }
3375}
3376
3377#[cfg(any(test, feature = "test-support"))]
3378impl MultiBuffer {
3379    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3380        let buffer = cx.new(|cx| Buffer::local(text, cx));
3381        cx.new(|cx| Self::singleton(buffer, cx))
3382    }
3383
3384    pub fn build_multi<const COUNT: usize>(
3385        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3386        cx: &mut gpui::App,
3387    ) -> Entity<Self> {
3388        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3389        for (text, ranges) in excerpts {
3390            let buffer = cx.new(|cx| Buffer::local(text, cx));
3391            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3392                context: range,
3393                primary: None,
3394            });
3395            multi.update(cx, |multi, cx| {
3396                multi.push_excerpts(buffer, excerpt_ranges, cx)
3397            });
3398        }
3399
3400        multi
3401    }
3402
3403    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3404        cx.new(|cx| Self::singleton(buffer, cx))
3405    }
3406
3407    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3408        cx.new(|cx| {
3409            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3410            let mutation_count = rng.gen_range(1..=5);
3411            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3412            multibuffer
3413        })
3414    }
3415
3416    pub fn randomly_edit(
3417        &mut self,
3418        rng: &mut impl rand::Rng,
3419        edit_count: usize,
3420        cx: &mut Context<Self>,
3421    ) {
3422        use util::RandomCharIter;
3423
3424        let snapshot = self.read(cx);
3425        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3426        let mut last_end = None;
3427        for _ in 0..edit_count {
3428            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3429                break;
3430            }
3431
3432            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3433            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3434            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3435            last_end = Some(end);
3436
3437            let mut range = start..end;
3438            if rng.gen_bool(0.2) {
3439                mem::swap(&mut range.start, &mut range.end);
3440            }
3441
3442            let new_text_len = rng.gen_range(0..10);
3443            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3444
3445            edits.push((range, new_text.into()));
3446        }
3447        log::info!("mutating multi-buffer with {:?}", edits);
3448        drop(snapshot);
3449
3450        self.edit(edits, None, cx);
3451    }
3452
3453    pub fn randomly_edit_excerpts(
3454        &mut self,
3455        rng: &mut impl rand::Rng,
3456        mutation_count: usize,
3457        cx: &mut Context<Self>,
3458    ) {
3459        use rand::prelude::*;
3460        use std::env;
3461        use util::RandomCharIter;
3462
3463        let max_excerpts = env::var("MAX_EXCERPTS")
3464            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3465            .unwrap_or(5);
3466
3467        let mut buffers = Vec::new();
3468        for _ in 0..mutation_count {
3469            if rng.gen_bool(0.05) {
3470                log::info!("Clearing multi-buffer");
3471                self.clear(cx);
3472                continue;
3473            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3474                let ids = self.excerpt_ids();
3475                let mut excerpts = HashSet::default();
3476                for _ in 0..rng.gen_range(0..ids.len()) {
3477                    excerpts.extend(ids.choose(rng).copied());
3478                }
3479
3480                let line_count = rng.gen_range(0..5);
3481
3482                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3483
3484                self.expand_excerpts(
3485                    excerpts.iter().cloned(),
3486                    line_count,
3487                    ExpandExcerptDirection::UpAndDown,
3488                    cx,
3489                );
3490                continue;
3491            }
3492
3493            let excerpt_ids = self.excerpt_ids();
3494            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3495                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3496                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3497                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3498                    let buffer = buffers.last().unwrap().read(cx);
3499                    log::info!(
3500                        "Creating new buffer {} with text: {:?}",
3501                        buffer.remote_id(),
3502                        buffer.text()
3503                    );
3504                    buffers.last().unwrap().clone()
3505                } else {
3506                    self.buffers
3507                        .borrow()
3508                        .values()
3509                        .choose(rng)
3510                        .unwrap()
3511                        .buffer
3512                        .clone()
3513                };
3514
3515                let buffer = buffer_handle.read(cx);
3516                let buffer_text = buffer.text();
3517                let ranges = (0..rng.gen_range(0..5))
3518                    .map(|_| {
3519                        let end_ix =
3520                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3521                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3522                        ExcerptRange {
3523                            context: start_ix..end_ix,
3524                            primary: None,
3525                        }
3526                    })
3527                    .collect::<Vec<_>>();
3528                log::info!(
3529                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3530                    buffer_handle.read(cx).remote_id(),
3531                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3532                    ranges
3533                        .iter()
3534                        .map(|r| &buffer_text[r.context.clone()])
3535                        .collect::<Vec<_>>()
3536                );
3537
3538                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3539                log::info!("Inserted with ids: {:?}", excerpt_id);
3540            } else {
3541                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3542                let mut excerpts_to_remove = excerpt_ids
3543                    .choose_multiple(rng, remove_count)
3544                    .cloned()
3545                    .collect::<Vec<_>>();
3546                let snapshot = self.snapshot.borrow();
3547                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3548                drop(snapshot);
3549                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3550                self.remove_excerpts(excerpts_to_remove, cx);
3551            }
3552        }
3553    }
3554
3555    pub fn randomly_mutate(
3556        &mut self,
3557        rng: &mut impl rand::Rng,
3558        mutation_count: usize,
3559        cx: &mut Context<Self>,
3560    ) {
3561        use rand::prelude::*;
3562
3563        if rng.gen_bool(0.7) || self.singleton {
3564            let buffer = self
3565                .buffers
3566                .borrow()
3567                .values()
3568                .choose(rng)
3569                .map(|state| state.buffer.clone());
3570
3571            if let Some(buffer) = buffer {
3572                buffer.update(cx, |buffer, cx| {
3573                    if rng.gen() {
3574                        buffer.randomly_edit(rng, mutation_count, cx);
3575                    } else {
3576                        buffer.randomly_undo_redo(rng, cx);
3577                    }
3578                });
3579            } else {
3580                self.randomly_edit(rng, mutation_count, cx);
3581            }
3582        } else {
3583            self.randomly_edit_excerpts(rng, mutation_count, cx);
3584        }
3585
3586        self.check_invariants(cx);
3587    }
3588
3589    fn check_invariants(&self, cx: &App) {
3590        self.read(cx).check_invariants();
3591    }
3592}
3593
3594impl EventEmitter<Event> for MultiBuffer {}
3595
3596impl MultiBufferSnapshot {
3597    pub fn text(&self) -> String {
3598        self.chunks(0..self.len(), false)
3599            .map(|chunk| chunk.text)
3600            .collect()
3601    }
3602
3603    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3604        self.reversed_chunks_in_range(0..position.to_offset(self))
3605            .flat_map(|c| c.chars().rev())
3606    }
3607
3608    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3609        let mut cursor = self.cursor::<usize>();
3610        cursor.seek(&range.end);
3611        let current_chunks = cursor.region().as_ref().map(|region| {
3612            let start_overshoot = range.start.saturating_sub(region.range.start);
3613            let end_overshoot = range.end - region.range.start;
3614            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3615            let start = region.buffer_range.start + start_overshoot;
3616            region.buffer.reversed_chunks_in_range(start..end)
3617        });
3618        ReversedMultiBufferChunks {
3619            cursor,
3620            current_chunks,
3621            start: range.start,
3622            offset: range.end,
3623        }
3624    }
3625
3626    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3627        let offset = position.to_offset(self);
3628        self.text_for_range(offset..self.len())
3629            .flat_map(|chunk| chunk.chars())
3630    }
3631
3632    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3633        self.chunks(range, false).map(|chunk| chunk.text)
3634    }
3635
3636    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3637        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3638            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3639    }
3640
3641    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3642    where
3643        T: ToOffset,
3644    {
3645        let position = position.to_offset(self);
3646        position == self.clip_offset(position, Bias::Left)
3647            && self
3648                .bytes_in_range(position..self.len())
3649                .flatten()
3650                .copied()
3651                .take(needle.len())
3652                .eq(needle.bytes())
3653    }
3654
3655    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3656        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3657    }
3658
3659    pub fn diff_hunks_in_range<T: ToPoint>(
3660        &self,
3661        range: Range<T>,
3662    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3663        let query_range = range.start.to_point(self)..range.end.to_point(self);
3664        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3665            let diff = self.diffs.get(&buffer.remote_id())?;
3666            let buffer_start = buffer.anchor_before(buffer_range.start);
3667            let buffer_end = buffer.anchor_after(buffer_range.end);
3668            Some(
3669                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3670                    .filter_map(|hunk| {
3671                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3672                            return None;
3673                        }
3674                        Some((hunk.range.clone(), hunk))
3675                    }),
3676            )
3677        })
3678        .filter_map(move |(range, hunk, excerpt)| {
3679            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3680            {
3681                return None;
3682            }
3683            let end_row = if range.end.column == 0 {
3684                range.end.row
3685            } else {
3686                range.end.row + 1
3687            };
3688            Some(MultiBufferDiffHunk {
3689                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3690                buffer_id: excerpt.buffer_id,
3691                excerpt_id: excerpt.id,
3692                buffer_range: hunk.buffer_range.clone(),
3693                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3694                secondary_status: hunk.secondary_status,
3695            })
3696        })
3697    }
3698
3699    pub fn excerpt_ids_for_range<T: ToOffset>(
3700        &self,
3701        range: Range<T>,
3702    ) -> impl Iterator<Item = ExcerptId> + '_ {
3703        let range = range.start.to_offset(self)..range.end.to_offset(self);
3704        let mut cursor = self.cursor::<usize>();
3705        cursor.seek(&range.start);
3706        std::iter::from_fn(move || {
3707            let region = cursor.region()?;
3708            if region.range.start >= range.end {
3709                return None;
3710            }
3711            cursor.next_excerpt();
3712            Some(region.excerpt.id)
3713        })
3714    }
3715
3716    pub fn buffer_ids_for_range<T: ToOffset>(
3717        &self,
3718        range: Range<T>,
3719    ) -> impl Iterator<Item = BufferId> + '_ {
3720        let range = range.start.to_offset(self)..range.end.to_offset(self);
3721        let mut cursor = self.cursor::<usize>();
3722        cursor.seek(&range.start);
3723        std::iter::from_fn(move || {
3724            let region = cursor.region()?;
3725            if region.range.start > range.end
3726                || region.range.start == range.end && region.range.start > range.start
3727            {
3728                return None;
3729            }
3730            cursor.next_excerpt();
3731            Some(region.excerpt.buffer_id)
3732        })
3733    }
3734
3735    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3736        &self,
3737        ranges: impl Iterator<Item = Range<T>>,
3738    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3739        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3740    }
3741
3742    pub fn range_to_buffer_ranges<T: ToOffset>(
3743        &self,
3744        range: Range<T>,
3745    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3746        let start = range.start.to_offset(&self);
3747        let end = range.end.to_offset(&self);
3748
3749        let mut cursor = self.cursor::<usize>();
3750        cursor.seek(&start);
3751
3752        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3753        while let Some(region) = cursor.region() {
3754            if region.range.start > end {
3755                break;
3756            }
3757            if region.is_main_buffer {
3758                let start_overshoot = start.saturating_sub(region.range.start);
3759                let end_overshoot = end.saturating_sub(region.range.start);
3760                let start = region
3761                    .buffer_range
3762                    .end
3763                    .min(region.buffer_range.start + start_overshoot);
3764                let end = region
3765                    .buffer_range
3766                    .end
3767                    .min(region.buffer_range.start + end_overshoot);
3768                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3769                    *excerpt_id == region.excerpt.id && prev_range.end == start
3770                }) {
3771                    prev.1.end = end;
3772                } else {
3773                    result.push((region.buffer, start..end, region.excerpt.id));
3774                }
3775            }
3776            cursor.next();
3777        }
3778        result
3779    }
3780
3781    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3782        &self,
3783        range: Range<T>,
3784    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3785        let start = range.start.to_offset(&self);
3786        let end = range.end.to_offset(&self);
3787
3788        let mut cursor = self.cursor::<usize>();
3789        cursor.seek(&start);
3790
3791        std::iter::from_fn(move || {
3792            let region = cursor.region()?;
3793            if region.range.start > end {
3794                return None;
3795            }
3796            let start_overshoot = start.saturating_sub(region.range.start);
3797            let end_overshoot = end.saturating_sub(region.range.start);
3798            let start = region
3799                .buffer_range
3800                .end
3801                .min(region.buffer_range.start + start_overshoot);
3802            let end = region
3803                .buffer_range
3804                .end
3805                .min(region.buffer_range.start + end_overshoot);
3806
3807            let region_excerpt_id = region.excerpt.id;
3808            let deleted_hunk_anchor = if region.is_main_buffer {
3809                None
3810            } else {
3811                Some(self.anchor_before(region.range.start))
3812            };
3813            let result = (
3814                region.buffer,
3815                start..end,
3816                region_excerpt_id,
3817                deleted_hunk_anchor,
3818            );
3819            cursor.next();
3820            Some(result)
3821        })
3822    }
3823
3824    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3825    /// coordinates.
3826    ///
3827    /// The given callback will be called for every excerpt intersecting the given range. It will
3828    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3829    /// The callback should return an iterator of metadata items from that buffer, each paired
3830    /// with a buffer range.
3831    ///
3832    /// The returned iterator yields each of these metadata items, paired with its range in
3833    /// multi-buffer coordinates.
3834    fn lift_buffer_metadata<'a, D, M, I>(
3835        &'a self,
3836        query_range: Range<D>,
3837        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3838    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3839    where
3840        I: Iterator<Item = (Range<D>, M)> + 'a,
3841        D: TextDimension + Ord + Sub<D, Output = D>,
3842    {
3843        let max_position = D::from_text_summary(&self.text_summary());
3844        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3845        let mut cursor = self.cursor::<D>();
3846
3847        // Find the excerpt and buffer offset where the given range ends.
3848        cursor.seek(&query_range.end);
3849        let mut range_end = None;
3850        while let Some(region) = cursor.region() {
3851            if region.is_main_buffer {
3852                let mut buffer_end = region.buffer_range.start;
3853                let overshoot = if query_range.end > region.range.start {
3854                    query_range.end - region.range.start
3855                } else {
3856                    D::default()
3857                };
3858                buffer_end.add_assign(&overshoot);
3859                range_end = Some((region.excerpt.id, buffer_end));
3860                break;
3861            }
3862            cursor.next();
3863        }
3864
3865        cursor.seek(&query_range.start);
3866
3867        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3868            if region.range.start > D::zero(&()) {
3869                cursor.prev()
3870            }
3871        }
3872
3873        iter::from_fn(move || loop {
3874            let excerpt = cursor.excerpt()?;
3875
3876            // If we have already retrieved metadata for this excerpt, continue to use it.
3877            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3878                .as_mut()
3879                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3880            {
3881                Some(metadata)
3882            }
3883            // Otherwise, compute the intersection of the input range with the excerpt's range,
3884            // and retrieve the metadata for the resulting range.
3885            else {
3886                let region = cursor.region()?;
3887                let mut buffer_start;
3888                if region.is_main_buffer {
3889                    buffer_start = region.buffer_range.start;
3890                    if query_range.start > region.range.start {
3891                        let overshoot = query_range.start - region.range.start;
3892                        buffer_start.add_assign(&overshoot);
3893                    }
3894                    buffer_start = buffer_start.min(region.buffer_range.end);
3895                } else {
3896                    buffer_start = cursor.main_buffer_position()?;
3897                };
3898                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3899                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3900                    if excerpt.id == end_excerpt_id {
3901                        buffer_end = buffer_end.min(end_buffer_offset);
3902                    }
3903                }
3904
3905                if let Some(iterator) =
3906                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3907                {
3908                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3909                } else {
3910                    None
3911                }
3912            };
3913
3914            // Visit each metadata item.
3915            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3916            {
3917                // Find the multibuffer regions that contain the start and end of
3918                // the metadata item's range.
3919                if metadata_buffer_range.start > D::default() {
3920                    while let Some(region) = cursor.region() {
3921                        if region.is_main_buffer
3922                            && (region.buffer_range.end >= metadata_buffer_range.start
3923                                || cursor.is_at_end_of_excerpt())
3924                        {
3925                            break;
3926                        }
3927                        cursor.next();
3928                    }
3929                }
3930                let start_region = cursor.region()?;
3931                while let Some(region) = cursor.region() {
3932                    if region.is_main_buffer
3933                        && (region.buffer_range.end > metadata_buffer_range.end
3934                            || cursor.is_at_end_of_excerpt())
3935                    {
3936                        break;
3937                    }
3938                    cursor.next();
3939                }
3940                let end_region = cursor.region();
3941
3942                // Convert the metadata item's range into multibuffer coordinates.
3943                let mut start_position = start_region.range.start;
3944                let region_buffer_start = start_region.buffer_range.start;
3945                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3946                {
3947                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3948                    start_position = start_position.min(start_region.range.end);
3949                }
3950
3951                let mut end_position = max_position;
3952                if let Some(end_region) = &end_region {
3953                    end_position = end_region.range.start;
3954                    debug_assert!(end_region.is_main_buffer);
3955                    let region_buffer_start = end_region.buffer_range.start;
3956                    if metadata_buffer_range.end > region_buffer_start {
3957                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3958                    }
3959                    end_position = end_position.min(end_region.range.end);
3960                }
3961
3962                if start_position <= query_range.end && end_position >= query_range.start {
3963                    return Some((start_position..end_position, metadata, excerpt));
3964                }
3965            }
3966            // When there are no more metadata items for this excerpt, move to the next excerpt.
3967            else {
3968                current_excerpt_metadata.take();
3969                if let Some((end_excerpt_id, _)) = range_end {
3970                    if excerpt.id == end_excerpt_id {
3971                        return None;
3972                    }
3973                }
3974                cursor.next_excerpt();
3975            }
3976        })
3977    }
3978
3979    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3980        let offset = position.to_offset(self);
3981
3982        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3983        cursor.seek(&DimensionPair {
3984            key: offset,
3985            value: None,
3986        });
3987        cursor.seek_to_start_of_current_excerpt();
3988        let excerpt = cursor.excerpt()?;
3989
3990        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3991        let current_position = self
3992            .anchor_before(offset)
3993            .text_anchor
3994            .to_offset(&excerpt.buffer);
3995        let excerpt_end = excerpt
3996            .buffer
3997            .anchor_before(excerpt_end.min(current_position));
3998
3999        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4000            for hunk in diff.hunks_intersecting_range_rev(
4001                excerpt.range.context.start..excerpt_end,
4002                &excerpt.buffer,
4003            ) {
4004                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4005                if hunk_end >= current_position {
4006                    continue;
4007                }
4008                let start =
4009                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4010                        .to_point(&self);
4011                return Some(MultiBufferRow(start.row));
4012            }
4013        }
4014
4015        loop {
4016            cursor.prev_excerpt();
4017            let excerpt = cursor.excerpt()?;
4018
4019            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4020                continue;
4021            };
4022            let mut hunks =
4023                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4024            let Some(hunk) = hunks.next() else {
4025                continue;
4026            };
4027            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4028                .to_point(&self);
4029            return Some(MultiBufferRow(start.row));
4030        }
4031    }
4032
4033    pub fn has_diff_hunks(&self) -> bool {
4034        self.diffs.values().any(|diff| !diff.is_empty())
4035    }
4036
4037    pub fn surrounding_word<T: ToOffset>(
4038        &self,
4039        start: T,
4040        for_completion: bool,
4041    ) -> (Range<usize>, Option<CharKind>) {
4042        let mut start = start.to_offset(self);
4043        let mut end = start;
4044        let mut next_chars = self.chars_at(start).peekable();
4045        let mut prev_chars = self.reversed_chars_at(start).peekable();
4046
4047        let classifier = self
4048            .char_classifier_at(start)
4049            .for_completion(for_completion);
4050
4051        let word_kind = cmp::max(
4052            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4053            next_chars.peek().copied().map(|c| classifier.kind(c)),
4054        );
4055
4056        for ch in prev_chars {
4057            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4058                start -= ch.len_utf8();
4059            } else {
4060                break;
4061            }
4062        }
4063
4064        for ch in next_chars {
4065            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4066                end += ch.len_utf8();
4067            } else {
4068                break;
4069            }
4070        }
4071
4072        (start..end, word_kind)
4073    }
4074
4075    pub fn is_singleton(&self) -> bool {
4076        self.singleton
4077    }
4078
4079    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4080        if self.singleton {
4081            self.excerpts
4082                .iter()
4083                .next()
4084                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4085        } else {
4086            None
4087        }
4088    }
4089
4090    pub fn len(&self) -> usize {
4091        self.diff_transforms.summary().output.len
4092    }
4093
4094    pub fn is_empty(&self) -> bool {
4095        self.excerpts.summary().text.len == 0
4096    }
4097
4098    pub fn widest_line_number(&self) -> u32 {
4099        self.excerpts.summary().widest_line_number + 1
4100    }
4101
4102    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
4103        let range = range.start.to_offset(self)..range.end.to_offset(self);
4104        let mut excerpts = self.cursor::<usize>();
4105        excerpts.seek(&range.start);
4106
4107        let mut chunk;
4108        let mut has_trailing_newline;
4109        let excerpt_bytes;
4110        if let Some(region) = excerpts.region() {
4111            let mut bytes = region.buffer.bytes_in_range(
4112                region.buffer_range.start + range.start - region.range.start
4113                    ..(region.buffer_range.start + range.end - region.range.start)
4114                        .min(region.buffer_range.end),
4115            );
4116            chunk = bytes.next().unwrap_or(&[][..]);
4117            excerpt_bytes = Some(bytes);
4118            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4119            if chunk.is_empty() && has_trailing_newline {
4120                chunk = b"\n";
4121                has_trailing_newline = false;
4122            }
4123        } else {
4124            chunk = &[][..];
4125            excerpt_bytes = None;
4126            has_trailing_newline = false;
4127        };
4128
4129        MultiBufferBytes {
4130            range,
4131            cursor: excerpts,
4132            excerpt_bytes,
4133            has_trailing_newline,
4134            chunk,
4135        }
4136    }
4137
4138    pub fn reversed_bytes_in_range<T: ToOffset>(
4139        &self,
4140        range: Range<T>,
4141    ) -> ReversedMultiBufferBytes {
4142        let range = range.start.to_offset(self)..range.end.to_offset(self);
4143        let mut chunks = self.reversed_chunks_in_range(range.clone());
4144        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4145        ReversedMultiBufferBytes {
4146            range,
4147            chunks,
4148            chunk,
4149        }
4150    }
4151
4152    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4153        let mut cursor = self.cursor::<Point>();
4154        cursor.seek(&Point::new(start_row.0, 0));
4155        let mut result = MultiBufferRows {
4156            point: Point::new(0, 0),
4157            is_empty: self.excerpts.is_empty(),
4158            is_singleton: self.is_singleton(),
4159            cursor,
4160        };
4161        result.seek(start_row);
4162        result
4163    }
4164
4165    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4166        let mut chunks = MultiBufferChunks {
4167            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4168            range: 0..0,
4169            excerpts: self.excerpts.cursor(&()),
4170            diff_transforms: self.diff_transforms.cursor(&()),
4171            diffs: &self.diffs,
4172            diff_base_chunks: None,
4173            excerpt_chunks: None,
4174            buffer_chunk: None,
4175            language_aware,
4176        };
4177        let range = range.start.to_offset(self)..range.end.to_offset(self);
4178        chunks.seek(range);
4179        chunks
4180    }
4181
4182    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4183        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4184    }
4185
4186    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4187        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4188    }
4189
4190    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4191        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4192    }
4193
4194    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4195        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4196            buffer.clip_point_utf16(Unclipped(point), bias)
4197        })
4198    }
4199
4200    pub fn offset_to_point(&self, offset: usize) -> Point {
4201        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4202    }
4203
4204    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4205        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4206    }
4207
4208    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4209        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4210    }
4211
4212    pub fn point_to_offset(&self, point: Point) -> usize {
4213        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4214    }
4215
4216    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4217        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4218    }
4219
4220    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4221        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4222    }
4223
4224    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4225        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4226    }
4227
4228    fn clip_dimension<D>(
4229        &self,
4230        position: D,
4231        bias: Bias,
4232        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4233    ) -> D
4234    where
4235        D: TextDimension + Ord + Sub<D, Output = D>,
4236    {
4237        let mut cursor = self.cursor();
4238        cursor.seek(&position);
4239        if let Some(region) = cursor.region() {
4240            if position >= region.range.end {
4241                return region.range.end;
4242            }
4243            let overshoot = position - region.range.start;
4244            let mut buffer_position = region.buffer_range.start;
4245            buffer_position.add_assign(&overshoot);
4246            let clipped_buffer_position =
4247                clip_buffer_position(&region.buffer, buffer_position, bias);
4248            let mut position = region.range.start;
4249            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4250            position
4251        } else {
4252            D::from_text_summary(&self.text_summary())
4253        }
4254    }
4255
4256    fn convert_dimension<D1, D2>(
4257        &self,
4258        key: D1,
4259        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4260    ) -> D2
4261    where
4262        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4263        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4264    {
4265        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4266        cursor.seek(&DimensionPair { key, value: None });
4267        if let Some(region) = cursor.region() {
4268            if key >= region.range.end.key {
4269                return region.range.end.value.unwrap();
4270            }
4271            let start_key = region.range.start.key;
4272            let start_value = region.range.start.value.unwrap();
4273            let buffer_start_key = region.buffer_range.start.key;
4274            let buffer_start_value = region.buffer_range.start.value.unwrap();
4275            let mut buffer_key = buffer_start_key;
4276            buffer_key.add_assign(&(key - start_key));
4277            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4278            let mut result = start_value;
4279            result.add_assign(&(buffer_value - buffer_start_value));
4280            result
4281        } else {
4282            D2::from_text_summary(&self.text_summary())
4283        }
4284    }
4285
4286    pub fn point_to_buffer_offset<T: ToOffset>(
4287        &self,
4288        point: T,
4289    ) -> Option<(&BufferSnapshot, usize)> {
4290        let offset = point.to_offset(self);
4291        let mut cursor = self.cursor::<usize>();
4292        cursor.seek(&offset);
4293        let region = cursor.region()?;
4294        let overshoot = offset - region.range.start;
4295        let buffer_offset = region.buffer_range.start + overshoot;
4296        if buffer_offset == region.buffer.len() + 1
4297            && region.has_trailing_newline
4298            && !region.is_main_buffer
4299        {
4300            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4301        } else if buffer_offset > region.buffer.len() {
4302            return None;
4303        }
4304        Some((region.buffer, buffer_offset))
4305    }
4306
4307    pub fn point_to_buffer_point(
4308        &self,
4309        point: Point,
4310    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4311        let mut cursor = self.cursor::<Point>();
4312        cursor.seek(&point);
4313        let region = cursor.region()?;
4314        let overshoot = point - region.range.start;
4315        let buffer_point = region.buffer_range.start + overshoot;
4316        let excerpt = cursor.excerpt()?;
4317        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4318            && region.has_trailing_newline
4319            && !region.is_main_buffer
4320        {
4321            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4322        } else if buffer_point > region.buffer.max_point() {
4323            return None;
4324        }
4325        Some((region.buffer, buffer_point, excerpt.id))
4326    }
4327
4328    pub fn suggested_indents(
4329        &self,
4330        rows: impl IntoIterator<Item = u32>,
4331        cx: &App,
4332    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4333        let mut result = BTreeMap::new();
4334
4335        let mut rows_for_excerpt = Vec::new();
4336        let mut cursor = self.cursor::<Point>();
4337        let mut rows = rows.into_iter().peekable();
4338        let mut prev_row = u32::MAX;
4339        let mut prev_language_indent_size = IndentSize::default();
4340
4341        while let Some(row) = rows.next() {
4342            cursor.seek(&Point::new(row, 0));
4343            let Some(region) = cursor.region() else {
4344                continue;
4345            };
4346
4347            // Retrieve the language and indent size once for each disjoint region being indented.
4348            let single_indent_size = if row.saturating_sub(1) == prev_row {
4349                prev_language_indent_size
4350            } else {
4351                region
4352                    .buffer
4353                    .language_indent_size_at(Point::new(row, 0), cx)
4354            };
4355            prev_language_indent_size = single_indent_size;
4356            prev_row = row;
4357
4358            let start_buffer_row = region.buffer_range.start.row;
4359            let start_multibuffer_row = region.range.start.row;
4360            let end_multibuffer_row = region.range.end.row;
4361
4362            rows_for_excerpt.push(row);
4363            while let Some(next_row) = rows.peek().copied() {
4364                if end_multibuffer_row > next_row {
4365                    rows_for_excerpt.push(next_row);
4366                    rows.next();
4367                } else {
4368                    break;
4369                }
4370            }
4371
4372            let buffer_rows = rows_for_excerpt
4373                .drain(..)
4374                .map(|row| start_buffer_row + row - start_multibuffer_row);
4375            let buffer_indents = region
4376                .buffer
4377                .suggested_indents(buffer_rows, single_indent_size);
4378            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4379                (
4380                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4381                    indent,
4382                )
4383            });
4384            result.extend(multibuffer_indents);
4385        }
4386
4387        result
4388    }
4389
4390    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4391        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4392            let mut size = buffer.indent_size_for_line(range.start.row);
4393            size.len = size
4394                .len
4395                .min(range.end.column)
4396                .saturating_sub(range.start.column);
4397            size
4398        } else {
4399            IndentSize::spaces(0)
4400        }
4401    }
4402
4403    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4404        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4405            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4406        } else {
4407            LineIndent::spaces(0)
4408        }
4409    }
4410
4411    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4412        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4413
4414        if self.language_settings(cx).extend_comment_on_newline {
4415            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4416                let delimiters = language_scope.line_comment_prefixes();
4417                for delimiter in delimiters {
4418                    if *self
4419                        .chars_at(Point::new(row.0, indent.len() as u32))
4420                        .take(delimiter.chars().count())
4421                        .collect::<String>()
4422                        .as_str()
4423                        == **delimiter
4424                    {
4425                        indent.push_str(&delimiter);
4426                        break;
4427                    }
4428                }
4429            }
4430        }
4431
4432        indent
4433    }
4434
4435    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4436    where
4437        T: ToOffset,
4438    {
4439        for char in self.reversed_chars_at(position) {
4440            if !char.is_whitespace() {
4441                return false;
4442            }
4443            if char == '\n' {
4444                return true;
4445            }
4446        }
4447        return true;
4448    }
4449
4450    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4451        while row.0 > 0 {
4452            row.0 -= 1;
4453            if !self.is_line_blank(row) {
4454                return Some(row);
4455            }
4456        }
4457        None
4458    }
4459
4460    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4461        if let Some((_, range)) = self.buffer_line_for_row(row) {
4462            range.end.column - range.start.column
4463        } else {
4464            0
4465        }
4466    }
4467
4468    pub fn buffer_line_for_row(
4469        &self,
4470        row: MultiBufferRow,
4471    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4472        let mut cursor = self.cursor::<Point>();
4473        let point = Point::new(row.0, 0);
4474        cursor.seek(&point);
4475        let region = cursor.region()?;
4476        let overshoot = point.min(region.range.end) - region.range.start;
4477        let buffer_point = region.buffer_range.start + overshoot;
4478        if buffer_point.row > region.buffer_range.end.row {
4479            return None;
4480        }
4481        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4482        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4483            .min(region.buffer_range.end);
4484        Some((region.buffer, line_start..line_end))
4485    }
4486
4487    pub fn max_point(&self) -> Point {
4488        self.text_summary().lines
4489    }
4490
4491    pub fn max_row(&self) -> MultiBufferRow {
4492        MultiBufferRow(self.text_summary().lines.row)
4493    }
4494
4495    pub fn text_summary(&self) -> TextSummary {
4496        self.diff_transforms.summary().output
4497    }
4498
4499    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4500    where
4501        D: TextDimension,
4502        O: ToOffset,
4503    {
4504        let range = range.start.to_offset(self)..range.end.to_offset(self);
4505        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4506        cursor.seek(&range.start, Bias::Right, &());
4507
4508        let Some(first_transform) = cursor.item() else {
4509            return D::from_text_summary(&TextSummary::default());
4510        };
4511
4512        let diff_transform_start = cursor.start().0;
4513        let diff_transform_end = cursor.end(&()).0;
4514        let diff_start = range.start;
4515        let start_overshoot = diff_start - diff_transform_start;
4516        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4517
4518        let mut result = match first_transform {
4519            DiffTransform::BufferContent { .. } => {
4520                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4521                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4522                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4523            }
4524            DiffTransform::DeletedHunk {
4525                buffer_id,
4526                base_text_byte_range,
4527                has_trailing_newline,
4528                ..
4529            } => {
4530                let buffer_start = base_text_byte_range.start + start_overshoot;
4531                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4532                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4533                    panic!("{:?} is in non-existent deleted hunk", range.start)
4534                };
4535
4536                let include_trailing_newline =
4537                    *has_trailing_newline && range.end >= diff_transform_end;
4538                if include_trailing_newline {
4539                    buffer_end -= 1;
4540                }
4541
4542                let mut summary =
4543                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4544
4545                if include_trailing_newline {
4546                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4547                }
4548
4549                summary
4550            }
4551        };
4552        if range.end < diff_transform_end {
4553            return result;
4554        }
4555
4556        cursor.next(&());
4557        result.add_assign(&D::from_text_summary(&cursor.summary(
4558            &range.end,
4559            Bias::Right,
4560            &(),
4561        )));
4562
4563        let Some(last_transform) = cursor.item() else {
4564            return result;
4565        };
4566
4567        let overshoot = range.end - cursor.start().0;
4568        let suffix = match last_transform {
4569            DiffTransform::BufferContent { .. } => {
4570                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4571                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4572            }
4573            DiffTransform::DeletedHunk {
4574                base_text_byte_range,
4575                buffer_id,
4576                has_trailing_newline,
4577                ..
4578            } => {
4579                let buffer_end = base_text_byte_range.start + overshoot;
4580                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4581                    panic!("{:?} is in non-existent deleted hunk", range.end)
4582                };
4583
4584                let mut suffix = base_text
4585                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4586                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4587                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4588                }
4589                suffix
4590            }
4591        };
4592
4593        result.add_assign(&suffix);
4594        result
4595    }
4596
4597    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4598    where
4599        D: TextDimension,
4600    {
4601        // let mut range = range.start..range.end;
4602        let mut summary = D::zero(&());
4603        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4604        cursor.seek(&range.start, Bias::Right, &());
4605        if let Some(excerpt) = cursor.item() {
4606            let mut end_before_newline = cursor.end(&());
4607            if excerpt.has_trailing_newline {
4608                end_before_newline -= ExcerptOffset::new(1);
4609            }
4610
4611            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4612            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4613            let end_in_excerpt =
4614                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4615            summary.add_assign(
4616                &excerpt
4617                    .buffer
4618                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4619            );
4620
4621            if range.end > end_before_newline {
4622                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4623            }
4624
4625            cursor.next(&());
4626        }
4627
4628        if range.end > *cursor.start() {
4629            summary.add_assign(
4630                &cursor
4631                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4632                    .0,
4633            );
4634            if let Some(excerpt) = cursor.item() {
4635                range.end = cmp::max(*cursor.start(), range.end);
4636
4637                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4638                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4639                summary.add_assign(
4640                    &excerpt
4641                        .buffer
4642                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4643                );
4644            }
4645        }
4646
4647        summary
4648    }
4649
4650    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4651    where
4652        D: TextDimension + Ord + Sub<D, Output = D>,
4653    {
4654        self.summaries_for_anchors([anchor])[0]
4655    }
4656
4657    fn resolve_summary_for_anchor<D>(
4658        &self,
4659        anchor: &Anchor,
4660        excerpt_position: D,
4661        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4662    ) -> D
4663    where
4664        D: TextDimension + Ord + Sub<D, Output = D>,
4665    {
4666        loop {
4667            let transform_end_position = diff_transforms.end(&()).0 .0;
4668            let at_transform_end =
4669                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4670            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4671                diff_transforms.next(&());
4672                continue;
4673            }
4674
4675            let mut position = diff_transforms.start().1 .0;
4676            match diff_transforms.item() {
4677                Some(DiffTransform::DeletedHunk {
4678                    buffer_id,
4679                    base_text_byte_range,
4680                    ..
4681                }) => {
4682                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4683                        if let Some(base_text) =
4684                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4685                        {
4686                            if base_text.can_resolve(&diff_base_anchor) {
4687                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4688                                if base_text_offset >= base_text_byte_range.start
4689                                    && base_text_offset <= base_text_byte_range.end
4690                                {
4691                                    let position_in_hunk = base_text
4692                                        .text_summary_for_range::<D, _>(
4693                                            base_text_byte_range.start..base_text_offset,
4694                                        );
4695                                    position.add_assign(&position_in_hunk);
4696                                } else if at_transform_end {
4697                                    diff_transforms.next(&());
4698                                    continue;
4699                                }
4700                            }
4701                        }
4702                    }
4703                }
4704                _ => {
4705                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4706                        diff_transforms.next(&());
4707                        continue;
4708                    }
4709                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4710                    position.add_assign(&overshoot);
4711                }
4712            }
4713
4714            return position;
4715        }
4716    }
4717
4718    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4719        let mut cursor = self
4720            .excerpts
4721            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4722        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4723
4724        cursor.seek(&Some(locator), Bias::Left, &());
4725        if cursor.item().is_none() {
4726            cursor.next(&());
4727        }
4728
4729        let mut position = cursor.start().1;
4730        if let Some(excerpt) = cursor.item() {
4731            if excerpt.id == anchor.excerpt_id {
4732                let excerpt_buffer_start = excerpt
4733                    .buffer
4734                    .offset_for_anchor(&excerpt.range.context.start);
4735                let excerpt_buffer_end =
4736                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4737                let buffer_position = cmp::min(
4738                    excerpt_buffer_end,
4739                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4740                );
4741                if buffer_position > excerpt_buffer_start {
4742                    position.value += buffer_position - excerpt_buffer_start;
4743                }
4744            }
4745        }
4746        position
4747    }
4748
4749    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4750    where
4751        D: TextDimension + Ord + Sub<D, Output = D>,
4752        I: 'a + IntoIterator<Item = &'a Anchor>,
4753    {
4754        let mut anchors = anchors.into_iter().peekable();
4755        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4756        let mut diff_transforms_cursor = self
4757            .diff_transforms
4758            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4759        diff_transforms_cursor.next(&());
4760
4761        let mut summaries = Vec::new();
4762        while let Some(anchor) = anchors.peek() {
4763            let excerpt_id = anchor.excerpt_id;
4764            let excerpt_anchors = iter::from_fn(|| {
4765                let anchor = anchors.peek()?;
4766                if anchor.excerpt_id == excerpt_id {
4767                    Some(anchors.next().unwrap())
4768                } else {
4769                    None
4770                }
4771            });
4772
4773            let locator = self.excerpt_locator_for_id(excerpt_id);
4774            cursor.seek_forward(locator, Bias::Left, &());
4775            if cursor.item().is_none() {
4776                cursor.next(&());
4777            }
4778
4779            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4780            if let Some(excerpt) = cursor.item() {
4781                if excerpt.id != excerpt_id {
4782                    let position = self.resolve_summary_for_anchor(
4783                        &Anchor::min(),
4784                        excerpt_start_position,
4785                        &mut diff_transforms_cursor,
4786                    );
4787                    summaries.extend(excerpt_anchors.map(|_| position));
4788                    continue;
4789                }
4790                let excerpt_buffer_start =
4791                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4792                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4793                for (buffer_summary, anchor) in excerpt
4794                    .buffer
4795                    .summaries_for_anchors_with_payload::<D, _, _>(
4796                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4797                    )
4798                {
4799                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4800                    let mut position = excerpt_start_position;
4801                    if summary > excerpt_buffer_start {
4802                        position.add_assign(&(summary - excerpt_buffer_start));
4803                    }
4804
4805                    if position > diff_transforms_cursor.start().0 .0 {
4806                        diff_transforms_cursor.seek_forward(
4807                            &ExcerptDimension(position),
4808                            Bias::Left,
4809                            &(),
4810                        );
4811                    }
4812
4813                    summaries.push(self.resolve_summary_for_anchor(
4814                        anchor,
4815                        position,
4816                        &mut diff_transforms_cursor,
4817                    ));
4818                }
4819            } else {
4820                diff_transforms_cursor.seek_forward(
4821                    &ExcerptDimension(excerpt_start_position),
4822                    Bias::Left,
4823                    &(),
4824                );
4825                let position = self.resolve_summary_for_anchor(
4826                    &Anchor::max(),
4827                    excerpt_start_position,
4828                    &mut diff_transforms_cursor,
4829                );
4830                summaries.extend(excerpt_anchors.map(|_| position));
4831            }
4832        }
4833
4834        summaries
4835    }
4836
4837    pub fn dimensions_from_points<'a, D>(
4838        &'a self,
4839        points: impl 'a + IntoIterator<Item = Point>,
4840    ) -> impl 'a + Iterator<Item = D>
4841    where
4842        D: TextDimension + Sub<D, Output = D>,
4843    {
4844        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4845        cursor.seek(&DimensionPair {
4846            key: Point::default(),
4847            value: None,
4848        });
4849        let mut points = points.into_iter();
4850        iter::from_fn(move || {
4851            let point = points.next()?;
4852
4853            cursor.seek_forward(&DimensionPair {
4854                key: point,
4855                value: None,
4856            });
4857
4858            if let Some(region) = cursor.region() {
4859                let overshoot = point - region.range.start.key;
4860                let buffer_point = region.buffer_range.start.key + overshoot;
4861                let mut position = region.range.start.value.unwrap();
4862                position.add_assign(
4863                    &region
4864                        .buffer
4865                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4866                );
4867                if point == region.range.end.key && region.has_trailing_newline {
4868                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4869                }
4870                return Some(position);
4871            } else {
4872                return Some(D::from_text_summary(&self.text_summary()));
4873            }
4874        })
4875    }
4876
4877    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4878    where
4879        I: 'a + IntoIterator<Item = &'a Anchor>,
4880    {
4881        let mut anchors = anchors.into_iter().enumerate().peekable();
4882        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4883        cursor.next(&());
4884
4885        let mut result = Vec::new();
4886
4887        while let Some((_, anchor)) = anchors.peek() {
4888            let old_excerpt_id = anchor.excerpt_id;
4889
4890            // Find the location where this anchor's excerpt should be.
4891            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4892            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4893
4894            if cursor.item().is_none() {
4895                cursor.next(&());
4896            }
4897
4898            let next_excerpt = cursor.item();
4899            let prev_excerpt = cursor.prev_item();
4900
4901            // Process all of the anchors for this excerpt.
4902            while let Some((_, anchor)) = anchors.peek() {
4903                if anchor.excerpt_id != old_excerpt_id {
4904                    break;
4905                }
4906                let (anchor_ix, anchor) = anchors.next().unwrap();
4907                let mut anchor = *anchor;
4908
4909                // Leave min and max anchors unchanged if invalid or
4910                // if the old excerpt still exists at this location
4911                let mut kept_position = next_excerpt
4912                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4913                    || old_excerpt_id == ExcerptId::max()
4914                    || old_excerpt_id == ExcerptId::min();
4915
4916                // If the old excerpt no longer exists at this location, then attempt to
4917                // find an equivalent position for this anchor in an adjacent excerpt.
4918                if !kept_position {
4919                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4920                        if excerpt.contains(&anchor) {
4921                            anchor.excerpt_id = excerpt.id;
4922                            kept_position = true;
4923                            break;
4924                        }
4925                    }
4926                }
4927
4928                // If there's no adjacent excerpt that contains the anchor's position,
4929                // then report that the anchor has lost its position.
4930                if !kept_position {
4931                    anchor = if let Some(excerpt) = next_excerpt {
4932                        let mut text_anchor = excerpt
4933                            .range
4934                            .context
4935                            .start
4936                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4937                        if text_anchor
4938                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4939                            .is_gt()
4940                        {
4941                            text_anchor = excerpt.range.context.end;
4942                        }
4943                        Anchor {
4944                            buffer_id: Some(excerpt.buffer_id),
4945                            excerpt_id: excerpt.id,
4946                            text_anchor,
4947                            diff_base_anchor: None,
4948                        }
4949                    } else if let Some(excerpt) = prev_excerpt {
4950                        let mut text_anchor = excerpt
4951                            .range
4952                            .context
4953                            .end
4954                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4955                        if text_anchor
4956                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4957                            .is_lt()
4958                        {
4959                            text_anchor = excerpt.range.context.start;
4960                        }
4961                        Anchor {
4962                            buffer_id: Some(excerpt.buffer_id),
4963                            excerpt_id: excerpt.id,
4964                            text_anchor,
4965                            diff_base_anchor: None,
4966                        }
4967                    } else if anchor.text_anchor.bias == Bias::Left {
4968                        Anchor::min()
4969                    } else {
4970                        Anchor::max()
4971                    };
4972                }
4973
4974                result.push((anchor_ix, anchor, kept_position));
4975            }
4976        }
4977        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4978        result
4979    }
4980
4981    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4982        self.anchor_at(position, Bias::Left)
4983    }
4984
4985    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4986        self.anchor_at(position, Bias::Right)
4987    }
4988
4989    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4990        let offset = position.to_offset(self);
4991
4992        // Find the given position in the diff transforms. Determine the corresponding
4993        // offset in the excerpts, and whether the position is within a deleted hunk.
4994        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4995        diff_transforms.seek(&offset, Bias::Right, &());
4996
4997        if offset == diff_transforms.start().0 && bias == Bias::Left {
4998            if let Some(prev_item) = diff_transforms.prev_item() {
4999                match prev_item {
5000                    DiffTransform::DeletedHunk { .. } => {
5001                        diff_transforms.prev(&());
5002                    }
5003                    _ => {}
5004                }
5005            }
5006        }
5007        let offset_in_transform = offset - diff_transforms.start().0;
5008        let mut excerpt_offset = diff_transforms.start().1;
5009        let mut diff_base_anchor = None;
5010        if let Some(DiffTransform::DeletedHunk {
5011            buffer_id,
5012            base_text_byte_range,
5013            has_trailing_newline,
5014            ..
5015        }) = diff_transforms.item()
5016        {
5017            let diff = self.diffs.get(buffer_id).expect("missing diff");
5018            if offset_in_transform > base_text_byte_range.len() {
5019                debug_assert!(*has_trailing_newline);
5020                bias = Bias::Right;
5021            } else {
5022                diff_base_anchor = Some(
5023                    diff.base_text()
5024                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5025                );
5026                bias = Bias::Left;
5027            }
5028        } else {
5029            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5030        };
5031
5032        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5033            return Anchor {
5034                buffer_id: Some(buffer_id),
5035                excerpt_id: *excerpt_id,
5036                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5037                diff_base_anchor,
5038            };
5039        }
5040
5041        let mut excerpts = self
5042            .excerpts
5043            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5044        excerpts.seek(&excerpt_offset, Bias::Right, &());
5045        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5046            excerpts.prev(&());
5047        }
5048        if let Some(excerpt) = excerpts.item() {
5049            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5050            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5051                overshoot -= 1;
5052                bias = Bias::Right;
5053            }
5054
5055            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5056            let text_anchor =
5057                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5058            Anchor {
5059                buffer_id: Some(excerpt.buffer_id),
5060                excerpt_id: excerpt.id,
5061                text_anchor,
5062                diff_base_anchor,
5063            }
5064        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5065            Anchor::min()
5066        } else {
5067            Anchor::max()
5068        }
5069    }
5070
5071    /// Returns an anchor for the given excerpt and text anchor,
5072    /// returns None if the excerpt_id is no longer valid.
5073    pub fn anchor_in_excerpt(
5074        &self,
5075        excerpt_id: ExcerptId,
5076        text_anchor: text::Anchor,
5077    ) -> Option<Anchor> {
5078        let locator = self.excerpt_locator_for_id(excerpt_id);
5079        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5080        cursor.seek(locator, Bias::Left, &());
5081        if let Some(excerpt) = cursor.item() {
5082            if excerpt.id == excerpt_id {
5083                let text_anchor = excerpt.clip_anchor(text_anchor);
5084                drop(cursor);
5085                return Some(Anchor {
5086                    buffer_id: Some(excerpt.buffer_id),
5087                    excerpt_id,
5088                    text_anchor,
5089                    diff_base_anchor: None,
5090                });
5091            }
5092        }
5093        None
5094    }
5095
5096    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5097        Some(self.excerpt(excerpt_id)?.range.context.clone())
5098    }
5099
5100    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5101        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5102            true
5103        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5104            excerpt.buffer.can_resolve(&anchor.text_anchor)
5105        } else {
5106            false
5107        }
5108    }
5109
5110    pub fn excerpts(
5111        &self,
5112    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5113        self.excerpts
5114            .iter()
5115            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5116    }
5117
5118    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
5119        let excerpts = self.excerpts.cursor(&());
5120        let diff_transforms = self.diff_transforms.cursor(&());
5121        MultiBufferCursor {
5122            excerpts,
5123            diff_transforms,
5124            diffs: &self.diffs,
5125            cached_region: None,
5126        }
5127    }
5128
5129    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5130        let start_locator = self.excerpt_locator_for_id(id);
5131        let mut excerpts = self
5132            .excerpts
5133            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5134        excerpts.seek(&Some(start_locator), Bias::Left, &());
5135        excerpts.prev(&());
5136
5137        let mut diff_transforms = self
5138            .diff_transforms
5139            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5140        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5141        if diff_transforms.end(&()).1 < excerpts.start().1 {
5142            diff_transforms.next(&());
5143        }
5144
5145        let excerpt = excerpts.item()?;
5146        Some(MultiBufferExcerpt {
5147            excerpt,
5148            offset: diff_transforms.start().0 .0,
5149            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5150            excerpt_offset: excerpts.start().1.clone(),
5151            diff_transforms,
5152        })
5153    }
5154
5155    pub fn excerpt_boundaries_in_range<R, T>(
5156        &self,
5157        range: R,
5158    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5159    where
5160        R: RangeBounds<T>,
5161        T: ToOffset,
5162    {
5163        let start_offset;
5164        let start = match range.start_bound() {
5165            Bound::Included(start) => {
5166                start_offset = start.to_offset(self);
5167                Bound::Included(start_offset)
5168            }
5169            Bound::Excluded(_) => {
5170                panic!("not supported")
5171            }
5172            Bound::Unbounded => {
5173                start_offset = 0;
5174                Bound::Unbounded
5175            }
5176        };
5177        let end = match range.end_bound() {
5178            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5179            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5180            Bound::Unbounded => Bound::Unbounded,
5181        };
5182        let bounds = (start, end);
5183
5184        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5185        cursor.seek(&DimensionPair {
5186            key: start_offset,
5187            value: None,
5188        });
5189
5190        if cursor
5191            .region()
5192            .is_some_and(|region| bounds.contains(&region.range.start.key))
5193        {
5194            cursor.prev_excerpt();
5195        } else {
5196            cursor.seek_to_start_of_current_excerpt();
5197        }
5198        let mut prev_region = cursor.region();
5199
5200        cursor.next_excerpt();
5201
5202        let mut visited_end = false;
5203        iter::from_fn(move || loop {
5204            if self.singleton {
5205                return None;
5206            }
5207
5208            let next_region = cursor.region();
5209            cursor.next_excerpt();
5210
5211            let next_region_start = if let Some(region) = &next_region {
5212                if !bounds.contains(&region.range.start.key) {
5213                    prev_region = next_region;
5214                    continue;
5215                }
5216                region.range.start.value.unwrap()
5217            } else {
5218                if !bounds.contains(&self.len()) {
5219                    return None;
5220                }
5221                self.max_point()
5222            };
5223            let next_region_end = if let Some(region) = cursor.region() {
5224                region.range.start.value.unwrap()
5225            } else {
5226                self.max_point()
5227            };
5228
5229            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5230                id: region.excerpt.id,
5231                buffer: region.excerpt.buffer.clone(),
5232                buffer_id: region.excerpt.buffer_id,
5233                range: region.excerpt.range.clone(),
5234                end_row: MultiBufferRow(next_region_start.row),
5235            });
5236
5237            let next = next_region.as_ref().map(|region| ExcerptInfo {
5238                id: region.excerpt.id,
5239                buffer: region.excerpt.buffer.clone(),
5240                buffer_id: region.excerpt.buffer_id,
5241                range: region.excerpt.range.clone(),
5242                end_row: if region.excerpt.has_trailing_newline {
5243                    MultiBufferRow(next_region_end.row - 1)
5244                } else {
5245                    MultiBufferRow(next_region_end.row)
5246                },
5247            });
5248
5249            if next.is_none() {
5250                if visited_end {
5251                    return None;
5252                } else {
5253                    visited_end = true;
5254                }
5255            }
5256
5257            let row = MultiBufferRow(next_region_start.row);
5258
5259            prev_region = next_region;
5260
5261            return Some(ExcerptBoundary { row, prev, next });
5262        })
5263    }
5264
5265    pub fn edit_count(&self) -> usize {
5266        self.edit_count
5267    }
5268
5269    pub fn non_text_state_update_count(&self) -> usize {
5270        self.non_text_state_update_count
5271    }
5272
5273    /// Returns the smallest enclosing bracket ranges containing the given range or
5274    /// None if no brackets contain range or the range is not contained in a single
5275    /// excerpt
5276    ///
5277    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5278    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5279        &self,
5280        range: Range<T>,
5281        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5282    ) -> Option<(Range<usize>, Range<usize>)> {
5283        let range = range.start.to_offset(self)..range.end.to_offset(self);
5284        let mut excerpt = self.excerpt_containing(range.clone())?;
5285        let buffer = excerpt.buffer();
5286        let excerpt_buffer_range = excerpt.buffer_range();
5287
5288        // Filter to ranges contained in the excerpt
5289        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5290            excerpt_buffer_range.contains(&open.start)
5291                && excerpt_buffer_range.contains(&close.end)
5292                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5293        };
5294
5295        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5296            excerpt.map_range_to_buffer(range),
5297            Some(&range_filter),
5298        )?;
5299
5300        Some((
5301            excerpt.map_range_from_buffer(open),
5302            excerpt.map_range_from_buffer(close),
5303        ))
5304    }
5305
5306    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5307    /// not contained in a single excerpt
5308    pub fn enclosing_bracket_ranges<T: ToOffset>(
5309        &self,
5310        range: Range<T>,
5311    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5312        let range = range.start.to_offset(self)..range.end.to_offset(self);
5313        let mut excerpt = self.excerpt_containing(range.clone())?;
5314
5315        Some(
5316            excerpt
5317                .buffer()
5318                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5319                .filter_map(move |pair| {
5320                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5321                        Some((
5322                            excerpt.map_range_from_buffer(pair.open_range),
5323                            excerpt.map_range_from_buffer(pair.close_range),
5324                        ))
5325                    } else {
5326                        None
5327                    }
5328                }),
5329        )
5330    }
5331
5332    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5333    /// not contained in a single excerpt
5334    pub fn text_object_ranges<T: ToOffset>(
5335        &self,
5336        range: Range<T>,
5337        options: TreeSitterOptions,
5338    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5339        let range = range.start.to_offset(self)..range.end.to_offset(self);
5340        self.excerpt_containing(range.clone())
5341            .map(|mut excerpt| {
5342                excerpt
5343                    .buffer()
5344                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5345                    .filter_map(move |(range, text_object)| {
5346                        if excerpt.contains_buffer_range(range.clone()) {
5347                            Some((excerpt.map_range_from_buffer(range), text_object))
5348                        } else {
5349                            None
5350                        }
5351                    })
5352            })
5353            .into_iter()
5354            .flatten()
5355    }
5356
5357    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5358    /// not contained in a single excerpt
5359    pub fn bracket_ranges<T: ToOffset>(
5360        &self,
5361        range: Range<T>,
5362    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5363        let range = range.start.to_offset(self)..range.end.to_offset(self);
5364        let mut excerpt = self.excerpt_containing(range.clone())?;
5365
5366        Some(
5367            excerpt
5368                .buffer()
5369                .bracket_ranges(excerpt.map_range_to_buffer(range))
5370                .filter_map(move |pair| {
5371                    let buffer_range = pair.open_range.start..pair.close_range.end;
5372                    if excerpt.contains_buffer_range(buffer_range) {
5373                        Some((
5374                            excerpt.map_range_from_buffer(pair.open_range),
5375                            excerpt.map_range_from_buffer(pair.close_range),
5376                        ))
5377                    } else {
5378                        None
5379                    }
5380                }),
5381        )
5382    }
5383
5384    pub fn redacted_ranges<'a, T: ToOffset>(
5385        &'a self,
5386        range: Range<T>,
5387        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5388    ) -> impl Iterator<Item = Range<usize>> + 'a {
5389        let range = range.start.to_offset(self)..range.end.to_offset(self);
5390        self.lift_buffer_metadata(range, move |buffer, range| {
5391            if redaction_enabled(buffer.file()) {
5392                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5393            } else {
5394                None
5395            }
5396        })
5397        .map(|(range, _, _)| range)
5398    }
5399
5400    pub fn runnable_ranges(
5401        &self,
5402        range: Range<Anchor>,
5403    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5404        let range = range.start.to_offset(self)..range.end.to_offset(self);
5405        self.lift_buffer_metadata(range, move |buffer, range| {
5406            Some(
5407                buffer
5408                    .runnable_ranges(range.clone())
5409                    .filter(move |runnable| {
5410                        runnable.run_range.start >= range.start
5411                            && runnable.run_range.end < range.end
5412                    })
5413                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5414            )
5415        })
5416        .map(|(run_range, runnable, _)| language::RunnableRange {
5417            run_range,
5418            ..runnable
5419        })
5420    }
5421
5422    pub fn line_indents(
5423        &self,
5424        start_row: MultiBufferRow,
5425        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5426    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5427        let max_point = self.max_point();
5428        let mut cursor = self.cursor::<Point>();
5429        cursor.seek(&Point::new(start_row.0, 0));
5430        iter::from_fn(move || {
5431            let mut region = cursor.region()?;
5432            while !buffer_filter(&region.excerpt.buffer) {
5433                cursor.next();
5434                region = cursor.region()?;
5435            }
5436            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5437            let buffer_start_row =
5438                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5439
5440            let buffer_end_row = if region.is_main_buffer
5441                && (region.has_trailing_newline || region.range.end == max_point)
5442            {
5443                region.buffer_range.end.row
5444            } else {
5445                region.buffer_range.end.row.saturating_sub(1)
5446            };
5447
5448            let line_indents = region
5449                .buffer
5450                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5451            cursor.next();
5452            return Some(line_indents.map(move |(buffer_row, indent)| {
5453                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5454                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5455            }));
5456        })
5457        .flatten()
5458    }
5459
5460    pub fn reversed_line_indents(
5461        &self,
5462        end_row: MultiBufferRow,
5463        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5464    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5465        let max_point = self.max_point();
5466        let mut cursor = self.cursor::<Point>();
5467        cursor.seek(&Point::new(end_row.0, 0));
5468        iter::from_fn(move || {
5469            let mut region = cursor.region()?;
5470            while !buffer_filter(&region.excerpt.buffer) {
5471                cursor.prev();
5472                region = cursor.region()?;
5473            }
5474
5475            let buffer_start_row = region.buffer_range.start.row;
5476            let buffer_end_row = if region.is_main_buffer
5477                && (region.has_trailing_newline || region.range.end == max_point)
5478            {
5479                region.buffer_range.end.row + 1
5480            } else {
5481                region.buffer_range.end.row
5482            };
5483
5484            let overshoot = end_row.0 - region.range.start.row;
5485            let buffer_end_row =
5486                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5487
5488            let line_indents = region
5489                .buffer
5490                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5491            cursor.prev();
5492            return Some(line_indents.map(move |(buffer_row, indent)| {
5493                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5494                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5495            }));
5496        })
5497        .flatten()
5498    }
5499
5500    pub async fn enclosing_indent(
5501        &self,
5502        mut target_row: MultiBufferRow,
5503    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5504        let max_row = MultiBufferRow(self.max_point().row);
5505        if target_row >= max_row {
5506            return None;
5507        }
5508
5509        let mut target_indent = self.line_indent_for_row(target_row);
5510
5511        // If the current row is at the start of an indented block, we want to return this
5512        // block as the enclosing indent.
5513        if !target_indent.is_line_empty() && target_row < max_row {
5514            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5515            if !next_line_indent.is_line_empty()
5516                && target_indent.raw_len() < next_line_indent.raw_len()
5517            {
5518                target_indent = next_line_indent;
5519                target_row.0 += 1;
5520            }
5521        }
5522
5523        const SEARCH_ROW_LIMIT: u32 = 25000;
5524        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5525        const YIELD_INTERVAL: u32 = 100;
5526
5527        let mut accessed_row_counter = 0;
5528
5529        // If there is a blank line at the current row, search for the next non indented lines
5530        if target_indent.is_line_empty() {
5531            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5532            let end =
5533                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5534
5535            let mut non_empty_line_above = None;
5536            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5537                if row < start {
5538                    break;
5539                }
5540                accessed_row_counter += 1;
5541                if accessed_row_counter == YIELD_INTERVAL {
5542                    accessed_row_counter = 0;
5543                    yield_now().await;
5544                }
5545                if !indent.is_line_empty() {
5546                    non_empty_line_above = Some((row, indent));
5547                    break;
5548                }
5549            }
5550
5551            let mut non_empty_line_below = None;
5552            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5553                if row > end {
5554                    break;
5555                }
5556                accessed_row_counter += 1;
5557                if accessed_row_counter == YIELD_INTERVAL {
5558                    accessed_row_counter = 0;
5559                    yield_now().await;
5560                }
5561                if !indent.is_line_empty() {
5562                    non_empty_line_below = Some((row, indent));
5563                    break;
5564                }
5565            }
5566
5567            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5568                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5569                    if above_indent.raw_len() >= below_indent.raw_len() {
5570                        (above_row, above_indent)
5571                    } else {
5572                        (below_row, below_indent)
5573                    }
5574                }
5575                (Some(above), None) => above,
5576                (None, Some(below)) => below,
5577                _ => return None,
5578            };
5579
5580            target_indent = indent;
5581            target_row = row;
5582        }
5583
5584        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5585        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5586
5587        let mut start_indent = None;
5588        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5589            if row < start {
5590                break;
5591            }
5592            accessed_row_counter += 1;
5593            if accessed_row_counter == YIELD_INTERVAL {
5594                accessed_row_counter = 0;
5595                yield_now().await;
5596            }
5597            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5598                start_indent = Some((row, indent));
5599                break;
5600            }
5601        }
5602        let (start_row, start_indent_size) = start_indent?;
5603
5604        let mut end_indent = (end, None);
5605        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5606            if row > end {
5607                break;
5608            }
5609            accessed_row_counter += 1;
5610            if accessed_row_counter == YIELD_INTERVAL {
5611                accessed_row_counter = 0;
5612                yield_now().await;
5613            }
5614            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5615                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5616                break;
5617            }
5618        }
5619        let (end_row, end_indent_size) = end_indent;
5620
5621        let indent = if let Some(end_indent_size) = end_indent_size {
5622            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5623                start_indent_size
5624            } else {
5625                end_indent_size
5626            }
5627        } else {
5628            start_indent_size
5629        };
5630
5631        Some((start_row..end_row, indent))
5632    }
5633
5634    pub fn indent_guides_in_range<T: ToPoint>(
5635        &self,
5636        range: Range<T>,
5637        ignore_disabled_for_language: bool,
5638        cx: &App,
5639    ) -> impl Iterator<Item = IndentGuide> {
5640        let range = range.start.to_point(self)..range.end.to_point(self);
5641        let start_row = MultiBufferRow(range.start.row);
5642        let end_row = MultiBufferRow(range.end.row);
5643
5644        let mut row_indents = self.line_indents(start_row, |buffer| {
5645            let settings =
5646                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5647            settings.indent_guides.enabled || ignore_disabled_for_language
5648        });
5649
5650        let mut result = Vec::new();
5651        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5652
5653        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5654            if first_row > end_row {
5655                break;
5656            }
5657            let current_depth = indent_stack.len() as u32;
5658
5659            let settings =
5660                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5661            let tab_size = settings.tab_size.get() as u32;
5662
5663            // When encountering empty, continue until found useful line indent
5664            // then add to the indent stack with the depth found
5665            let mut found_indent = false;
5666            let mut last_row = first_row;
5667            if line_indent.is_line_empty() {
5668                while !found_indent {
5669                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5670                        break;
5671                    };
5672                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5673                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5674                        break;
5675                    }
5676
5677                    if new_line_indent.is_line_empty() {
5678                        continue;
5679                    }
5680                    last_row = target_row.min(end_row);
5681                    line_indent = new_line_indent;
5682                    found_indent = true;
5683                    break;
5684                }
5685            } else {
5686                found_indent = true
5687            }
5688
5689            let depth = if found_indent {
5690                line_indent.len(tab_size) / tab_size
5691                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5692            } else {
5693                current_depth
5694            };
5695
5696            match depth.cmp(&current_depth) {
5697                cmp::Ordering::Less => {
5698                    for _ in 0..(current_depth - depth) {
5699                        let mut indent = indent_stack.pop().unwrap();
5700                        if last_row != first_row {
5701                            // In this case, we landed on an empty row, had to seek forward,
5702                            // and discovered that the indent we where on is ending.
5703                            // This means that the last display row must
5704                            // be on line that ends this indent range, so we
5705                            // should display the range up to the first non-empty line
5706                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5707                        }
5708
5709                        result.push(indent)
5710                    }
5711                }
5712                cmp::Ordering::Greater => {
5713                    for next_depth in current_depth..depth {
5714                        indent_stack.push(IndentGuide {
5715                            buffer_id: buffer.remote_id(),
5716                            start_row: first_row,
5717                            end_row: last_row,
5718                            depth: next_depth,
5719                            tab_size,
5720                            settings: settings.indent_guides,
5721                        });
5722                    }
5723                }
5724                _ => {}
5725            }
5726
5727            for indent in indent_stack.iter_mut() {
5728                indent.end_row = last_row;
5729            }
5730        }
5731
5732        result.extend(indent_stack);
5733        result.into_iter()
5734    }
5735
5736    pub fn trailing_excerpt_update_count(&self) -> usize {
5737        self.trailing_excerpt_update_count
5738    }
5739
5740    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5741        self.point_to_buffer_offset(point)
5742            .and_then(|(buffer, _)| buffer.file())
5743    }
5744
5745    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5746        self.point_to_buffer_offset(point)
5747            .and_then(|(buffer, offset)| buffer.language_at(offset))
5748    }
5749
5750    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5751        self.excerpts
5752            .first()
5753            .map(|excerpt| &excerpt.buffer)
5754            .map(|buffer| {
5755                language_settings(
5756                    buffer.language().map(|language| language.name()),
5757                    buffer.file(),
5758                    cx,
5759                )
5760            })
5761            .unwrap_or_else(move || self.language_settings_at(0, cx))
5762    }
5763
5764    pub fn language_settings_at<'a, T: ToOffset>(
5765        &'a self,
5766        point: T,
5767        cx: &'a App,
5768    ) -> Cow<'a, LanguageSettings> {
5769        let mut language = None;
5770        let mut file = None;
5771        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5772            language = buffer.language_at(offset);
5773            file = buffer.file();
5774        }
5775        language_settings(language.map(|l| l.name()), file, cx)
5776    }
5777
5778    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5779        self.point_to_buffer_offset(point)
5780            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5781    }
5782
5783    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5784        self.point_to_buffer_offset(point)
5785            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5786            .unwrap_or_default()
5787    }
5788
5789    pub fn language_indent_size_at<T: ToOffset>(
5790        &self,
5791        position: T,
5792        cx: &App,
5793    ) -> Option<IndentSize> {
5794        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5795        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5796    }
5797
5798    pub fn is_dirty(&self) -> bool {
5799        self.is_dirty
5800    }
5801
5802    pub fn has_deleted_file(&self) -> bool {
5803        self.has_deleted_file
5804    }
5805
5806    pub fn has_conflict(&self) -> bool {
5807        self.has_conflict
5808    }
5809
5810    pub fn has_diagnostics(&self) -> bool {
5811        self.excerpts
5812            .iter()
5813            .any(|excerpt| excerpt.buffer.has_diagnostics())
5814    }
5815
5816    pub fn diagnostic_group(
5817        &self,
5818        buffer_id: BufferId,
5819        group_id: usize,
5820    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5821        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5822            if buffer.remote_id() != buffer_id {
5823                return None;
5824            };
5825            Some(
5826                buffer
5827                    .diagnostic_group(group_id)
5828                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5829            )
5830        })
5831        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5832    }
5833
5834    pub fn diagnostics_in_range<'a, T>(
5835        &'a self,
5836        range: Range<T>,
5837    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5838    where
5839        T: 'a
5840            + text::ToOffset
5841            + text::FromAnchor
5842            + TextDimension
5843            + Ord
5844            + Sub<T, Output = T>
5845            + fmt::Debug,
5846    {
5847        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5848            Some(
5849                buffer
5850                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5851                    .map(|entry| (entry.range, entry.diagnostic)),
5852            )
5853        })
5854        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5855    }
5856
5857    pub fn syntax_ancestor<T: ToOffset>(
5858        &self,
5859        range: Range<T>,
5860    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5861        let range = range.start.to_offset(self)..range.end.to_offset(self);
5862        let mut excerpt = self.excerpt_containing(range.clone())?;
5863        let node = excerpt
5864            .buffer()
5865            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5866        let node_range = node.byte_range();
5867        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5868            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5869        } else {
5870            MultiOrSingleBufferOffsetRange::Single(node_range)
5871        };
5872        Some((node, range))
5873    }
5874
5875    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5876        let (excerpt_id, _, buffer) = self.as_singleton()?;
5877        let outline = buffer.outline(theme)?;
5878        Some(Outline::new(
5879            outline
5880                .items
5881                .into_iter()
5882                .flat_map(|item| {
5883                    Some(OutlineItem {
5884                        depth: item.depth,
5885                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5886                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5887                        text: item.text,
5888                        highlight_ranges: item.highlight_ranges,
5889                        name_ranges: item.name_ranges,
5890                        body_range: item.body_range.and_then(|body_range| {
5891                            Some(
5892                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5893                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5894                            )
5895                        }),
5896                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5897                            Some(
5898                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5899                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5900                            )
5901                        }),
5902                    })
5903                })
5904                .collect(),
5905        ))
5906    }
5907
5908    pub fn symbols_containing<T: ToOffset>(
5909        &self,
5910        offset: T,
5911        theme: Option<&SyntaxTheme>,
5912    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5913        let anchor = self.anchor_before(offset);
5914        let excerpt_id = anchor.excerpt_id;
5915        let excerpt = self.excerpt(excerpt_id)?;
5916        Some((
5917            excerpt.buffer_id,
5918            excerpt
5919                .buffer
5920                .symbols_containing(anchor.text_anchor, theme)
5921                .into_iter()
5922                .flatten()
5923                .flat_map(|item| {
5924                    Some(OutlineItem {
5925                        depth: item.depth,
5926                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5927                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5928                        text: item.text,
5929                        highlight_ranges: item.highlight_ranges,
5930                        name_ranges: item.name_ranges,
5931                        body_range: item.body_range.and_then(|body_range| {
5932                            Some(
5933                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5934                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5935                            )
5936                        }),
5937                        annotation_range: item.annotation_range.and_then(|body_range| {
5938                            Some(
5939                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5940                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5941                            )
5942                        }),
5943                    })
5944                })
5945                .collect(),
5946        ))
5947    }
5948
5949    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5950        if id == ExcerptId::min() {
5951            Locator::min_ref()
5952        } else if id == ExcerptId::max() {
5953            Locator::max_ref()
5954        } else {
5955            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5956            cursor.seek(&id, Bias::Left, &());
5957            if let Some(entry) = cursor.item() {
5958                if entry.id == id {
5959                    return &entry.locator;
5960                }
5961            }
5962            panic!("invalid excerpt id {:?}", id)
5963        }
5964    }
5965
5966    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5967    fn excerpt_locators_for_ids(
5968        &self,
5969        ids: impl IntoIterator<Item = ExcerptId>,
5970    ) -> SmallVec<[Locator; 1]> {
5971        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5972        sorted_ids.sort_unstable();
5973        let mut locators = SmallVec::new();
5974
5975        while sorted_ids.last() == Some(&ExcerptId::max()) {
5976            sorted_ids.pop();
5977            if let Some(mapping) = self.excerpt_ids.last() {
5978                locators.push(mapping.locator.clone());
5979            }
5980        }
5981
5982        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5983        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5984            sorted_ids.next();
5985            if let Some(mapping) = self.excerpt_ids.first() {
5986                locators.push(mapping.locator.clone());
5987            }
5988        }
5989
5990        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5991        for id in sorted_ids {
5992            if cursor.seek_forward(&id, Bias::Left, &()) {
5993                locators.push(cursor.item().unwrap().locator.clone());
5994            } else {
5995                panic!("invalid excerpt id {:?}", id);
5996            }
5997        }
5998
5999        locators.sort_unstable();
6000        locators
6001    }
6002
6003    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6004        Some(self.excerpt(excerpt_id)?.buffer_id)
6005    }
6006
6007    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6008        Some(&self.excerpt(excerpt_id)?.buffer)
6009    }
6010
6011    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6012        let mut cursor = self
6013            .excerpts
6014            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6015        let locator = self.excerpt_locator_for_id(excerpt_id);
6016        if cursor.seek(&Some(locator), Bias::Left, &()) {
6017            let start = cursor.start().1.clone();
6018            let end = cursor.end(&()).1;
6019            let mut diff_transforms = self
6020                .diff_transforms
6021                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6022            diff_transforms.seek(&start, Bias::Left, &());
6023            let overshoot = start.0 - diff_transforms.start().0 .0;
6024            let start = diff_transforms.start().1 .0 + overshoot;
6025            diff_transforms.seek(&end, Bias::Right, &());
6026            let overshoot = end.0 - diff_transforms.start().0 .0;
6027            let end = diff_transforms.start().1 .0 + overshoot;
6028            Some(start..end)
6029        } else {
6030            None
6031        }
6032    }
6033
6034    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6035        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6036        let locator = self.excerpt_locator_for_id(excerpt_id);
6037        if cursor.seek(&Some(locator), Bias::Left, &()) {
6038            if let Some(excerpt) = cursor.item() {
6039                return Some(excerpt.range.context.clone());
6040            }
6041        }
6042        None
6043    }
6044
6045    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6046        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6047        let locator = self.excerpt_locator_for_id(excerpt_id);
6048        cursor.seek(&Some(locator), Bias::Left, &());
6049        if let Some(excerpt) = cursor.item() {
6050            if excerpt.id == excerpt_id {
6051                return Some(excerpt);
6052            }
6053        }
6054        None
6055    }
6056
6057    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6058    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
6059        let range = range.start.to_offset(self)..range.end.to_offset(self);
6060        let mut cursor = self.cursor::<usize>();
6061        cursor.seek(&range.start);
6062
6063        let start_excerpt = cursor.excerpt()?;
6064        if range.end != range.start {
6065            cursor.seek_forward(&range.end);
6066            if cursor.excerpt()?.id != start_excerpt.id {
6067                return None;
6068            }
6069        }
6070
6071        cursor.seek_to_start_of_current_excerpt();
6072        let region = cursor.region()?;
6073        let offset = region.range.start;
6074        let buffer_offset = region.buffer_range.start;
6075        let excerpt_offset = cursor.excerpts.start().clone();
6076        Some(MultiBufferExcerpt {
6077            diff_transforms: cursor.diff_transforms,
6078            excerpt: start_excerpt,
6079            offset,
6080            buffer_offset,
6081            excerpt_offset,
6082        })
6083    }
6084
6085    pub fn selections_in_range<'a>(
6086        &'a self,
6087        range: &'a Range<Anchor>,
6088        include_local: bool,
6089    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6090        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6091        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6092        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6093        cursor.seek(start_locator, Bias::Left, &());
6094        cursor
6095            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6096            .flat_map(move |excerpt| {
6097                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6098                if excerpt.id == range.start.excerpt_id {
6099                    query_range.start = range.start.text_anchor;
6100                }
6101                if excerpt.id == range.end.excerpt_id {
6102                    query_range.end = range.end.text_anchor;
6103                }
6104
6105                excerpt
6106                    .buffer
6107                    .selections_in_range(query_range, include_local)
6108                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6109                        selections.map(move |selection| {
6110                            let mut start = Anchor {
6111                                buffer_id: Some(excerpt.buffer_id),
6112                                excerpt_id: excerpt.id,
6113                                text_anchor: selection.start,
6114                                diff_base_anchor: None,
6115                            };
6116                            let mut end = Anchor {
6117                                buffer_id: Some(excerpt.buffer_id),
6118                                excerpt_id: excerpt.id,
6119                                text_anchor: selection.end,
6120                                diff_base_anchor: None,
6121                            };
6122                            if range.start.cmp(&start, self).is_gt() {
6123                                start = range.start;
6124                            }
6125                            if range.end.cmp(&end, self).is_lt() {
6126                                end = range.end;
6127                            }
6128
6129                            (
6130                                replica_id,
6131                                line_mode,
6132                                cursor_shape,
6133                                Selection {
6134                                    id: selection.id,
6135                                    start,
6136                                    end,
6137                                    reversed: selection.reversed,
6138                                    goal: selection.goal,
6139                                },
6140                            )
6141                        })
6142                    })
6143            })
6144    }
6145
6146    pub fn show_headers(&self) -> bool {
6147        self.show_headers
6148    }
6149
6150    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6151        self.diffs.get(&buffer_id)
6152    }
6153}
6154
6155#[cfg(any(test, feature = "test-support"))]
6156impl MultiBufferSnapshot {
6157    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6158        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6159        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6160        start..end
6161    }
6162
6163    #[cfg(any(test, feature = "test-support"))]
6164    fn check_invariants(&self) {
6165        let excerpts = self.excerpts.items(&());
6166        let excerpt_ids = self.excerpt_ids.items(&());
6167
6168        for (ix, excerpt) in excerpts.iter().enumerate() {
6169            if ix == 0 {
6170                if excerpt.locator <= Locator::min() {
6171                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6172                }
6173            } else if excerpt.locator <= excerpts[ix - 1].locator {
6174                panic!("excerpts are out-of-order: {:?}", excerpts);
6175            }
6176        }
6177
6178        for (ix, entry) in excerpt_ids.iter().enumerate() {
6179            if ix == 0 {
6180                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6181                    panic!("invalid first excerpt id {:?}", entry.id);
6182                }
6183            } else if entry.id <= excerpt_ids[ix - 1].id {
6184                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6185            }
6186        }
6187
6188        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6189            panic!(
6190                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6191                self.excerpts.summary().text.len,
6192                self.diff_transforms.summary().input,
6193                self.diff_transforms.items(&()),
6194            );
6195        }
6196
6197        let mut prev_transform: Option<&DiffTransform> = None;
6198        for item in self.diff_transforms.iter() {
6199            if let DiffTransform::BufferContent {
6200                summary,
6201                inserted_hunk_info,
6202            } = item
6203            {
6204                if let Some(DiffTransform::BufferContent {
6205                    inserted_hunk_info: prev_inserted_hunk_info,
6206                    ..
6207                }) = prev_transform
6208                {
6209                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6210                        panic!(
6211                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6212                            self.diff_transforms.items(&()));
6213                    }
6214                }
6215                if summary.len == 0 && !self.is_empty() {
6216                    panic!("empty buffer content transform");
6217                }
6218            }
6219            prev_transform = Some(item);
6220        }
6221    }
6222}
6223
6224impl<'a, D> MultiBufferCursor<'a, D>
6225where
6226    D: TextDimension + Ord + Sub<D, Output = D>,
6227{
6228    fn seek(&mut self, position: &D) {
6229        self.cached_region.take();
6230        self.diff_transforms
6231            .seek(&OutputDimension(*position), Bias::Right, &());
6232        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6233            self.diff_transforms.prev(&());
6234        }
6235
6236        let mut excerpt_position = self.diff_transforms.start().1 .0;
6237        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6238            let overshoot = *position - self.diff_transforms.start().0 .0;
6239            excerpt_position.add_assign(&overshoot);
6240        }
6241
6242        self.excerpts
6243            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6244        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6245            self.excerpts.prev(&());
6246        }
6247    }
6248
6249    fn seek_forward(&mut self, position: &D) {
6250        self.cached_region.take();
6251        self.diff_transforms
6252            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6253        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6254            self.diff_transforms.prev(&());
6255        }
6256
6257        let overshoot = *position - self.diff_transforms.start().0 .0;
6258        let mut excerpt_position = self.diff_transforms.start().1 .0;
6259        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6260            excerpt_position.add_assign(&overshoot);
6261        }
6262
6263        self.excerpts
6264            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6265        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6266            self.excerpts.prev(&());
6267        }
6268    }
6269
6270    fn next_excerpt(&mut self) {
6271        self.excerpts.next(&());
6272        self.seek_to_start_of_current_excerpt();
6273    }
6274
6275    fn prev_excerpt(&mut self) {
6276        self.excerpts.prev(&());
6277        self.seek_to_start_of_current_excerpt();
6278    }
6279
6280    fn seek_to_start_of_current_excerpt(&mut self) {
6281        self.cached_region.take();
6282        self.diff_transforms
6283            .seek(self.excerpts.start(), Bias::Left, &());
6284        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6285            && self.diff_transforms.start().1 < *self.excerpts.start()
6286            && self.diff_transforms.next_item().is_some()
6287        {
6288            self.diff_transforms.next(&());
6289        }
6290    }
6291
6292    fn next(&mut self) {
6293        self.cached_region.take();
6294        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6295            cmp::Ordering::Less => self.diff_transforms.next(&()),
6296            cmp::Ordering::Greater => self.excerpts.next(&()),
6297            cmp::Ordering::Equal => {
6298                self.diff_transforms.next(&());
6299                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6300                    || self.diff_transforms.item().is_none()
6301                {
6302                    self.excerpts.next(&());
6303                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6304                    self.diff_transforms.item()
6305                {
6306                    if self
6307                        .excerpts
6308                        .item()
6309                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6310                    {
6311                        self.excerpts.next(&());
6312                    }
6313                }
6314            }
6315        }
6316    }
6317
6318    fn prev(&mut self) {
6319        self.cached_region.take();
6320        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6321            cmp::Ordering::Less => self.excerpts.prev(&()),
6322            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6323            cmp::Ordering::Equal => {
6324                self.diff_transforms.prev(&());
6325                if self.diff_transforms.start().1 < *self.excerpts.start()
6326                    || self.diff_transforms.item().is_none()
6327                {
6328                    self.excerpts.prev(&());
6329                }
6330            }
6331        }
6332    }
6333
6334    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6335        if self.cached_region.is_none() {
6336            self.cached_region = self.build_region();
6337        }
6338        self.cached_region.clone()
6339    }
6340
6341    fn is_at_start_of_excerpt(&mut self) -> bool {
6342        if self.diff_transforms.start().1 > *self.excerpts.start() {
6343            return false;
6344        } else if self.diff_transforms.start().1 < *self.excerpts.start() {
6345            return true;
6346        }
6347
6348        self.diff_transforms.prev(&());
6349        let prev_transform = self.diff_transforms.item();
6350        self.diff_transforms.next(&());
6351
6352        prev_transform.map_or(true, |next_transform| {
6353            matches!(next_transform, DiffTransform::BufferContent { .. })
6354        })
6355    }
6356
6357    fn is_at_end_of_excerpt(&mut self) -> bool {
6358        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6359            return false;
6360        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6361            || self.diff_transforms.item().is_none()
6362        {
6363            return true;
6364        }
6365
6366        let next_transform = self.diff_transforms.next_item();
6367        next_transform.map_or(true, |next_transform| match next_transform {
6368            DiffTransform::BufferContent { .. } => true,
6369            DiffTransform::DeletedHunk { hunk_info, .. } => self
6370                .excerpts
6371                .item()
6372                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6373        })
6374    }
6375
6376    fn main_buffer_position(&self) -> Option<D> {
6377        let excerpt = self.excerpts.item()?;
6378        let buffer = &excerpt.buffer;
6379        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6380        let mut buffer_start = buffer_context_start;
6381        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6382        buffer_start.add_assign(&overshoot);
6383        Some(buffer_start)
6384    }
6385
6386    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6387        let excerpt = self.excerpts.item()?;
6388        match self.diff_transforms.item()? {
6389            DiffTransform::DeletedHunk {
6390                buffer_id,
6391                base_text_byte_range,
6392                has_trailing_newline,
6393                hunk_info,
6394                ..
6395            } => {
6396                let diff = self.diffs.get(&buffer_id)?;
6397                let buffer = diff.base_text();
6398                let mut rope_cursor = buffer.as_rope().cursor(0);
6399                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6400                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6401                let mut buffer_end = buffer_start;
6402                buffer_end.add_assign(&buffer_range_len);
6403                let start = self.diff_transforms.start().0 .0;
6404                let end = self.diff_transforms.end(&()).0 .0;
6405                return Some(MultiBufferRegion {
6406                    buffer,
6407                    excerpt,
6408                    has_trailing_newline: *has_trailing_newline,
6409                    is_main_buffer: false,
6410                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6411                        hunk_info.hunk_secondary_status,
6412                    )),
6413                    buffer_range: buffer_start..buffer_end,
6414                    range: start..end,
6415                });
6416            }
6417            DiffTransform::BufferContent {
6418                inserted_hunk_info, ..
6419            } => {
6420                let buffer = &excerpt.buffer;
6421                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6422
6423                let mut start = self.diff_transforms.start().0 .0;
6424                let mut buffer_start = buffer_context_start;
6425                if self.diff_transforms.start().1 < *self.excerpts.start() {
6426                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6427                    start.add_assign(&overshoot);
6428                } else {
6429                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6430                    buffer_start.add_assign(&overshoot);
6431                }
6432
6433                let mut end;
6434                let mut buffer_end;
6435                let has_trailing_newline;
6436                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6437                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6438                    end = self.diff_transforms.end(&()).0 .0;
6439                    buffer_end = buffer_context_start;
6440                    buffer_end.add_assign(&overshoot);
6441                    has_trailing_newline = false;
6442                } else {
6443                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6444                    end = self.diff_transforms.start().0 .0;
6445                    end.add_assign(&overshoot);
6446                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6447                    has_trailing_newline = excerpt.has_trailing_newline;
6448                };
6449
6450                Some(MultiBufferRegion {
6451                    buffer,
6452                    excerpt,
6453                    has_trailing_newline,
6454                    is_main_buffer: true,
6455                    diff_hunk_status: inserted_hunk_info
6456                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6457                    buffer_range: buffer_start..buffer_end,
6458                    range: start..end,
6459                })
6460            }
6461        }
6462    }
6463
6464    fn excerpt(&self) -> Option<&'a Excerpt> {
6465        self.excerpts.item()
6466    }
6467}
6468
6469impl History {
6470    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6471        self.transaction_depth += 1;
6472        if self.transaction_depth == 1 {
6473            let id = self.next_transaction_id.tick();
6474            self.undo_stack.push(Transaction {
6475                id,
6476                buffer_transactions: Default::default(),
6477                first_edit_at: now,
6478                last_edit_at: now,
6479                suppress_grouping: false,
6480            });
6481            Some(id)
6482        } else {
6483            None
6484        }
6485    }
6486
6487    fn end_transaction(
6488        &mut self,
6489        now: Instant,
6490        buffer_transactions: HashMap<BufferId, TransactionId>,
6491    ) -> bool {
6492        assert_ne!(self.transaction_depth, 0);
6493        self.transaction_depth -= 1;
6494        if self.transaction_depth == 0 {
6495            if buffer_transactions.is_empty() {
6496                self.undo_stack.pop();
6497                false
6498            } else {
6499                self.redo_stack.clear();
6500                let transaction = self.undo_stack.last_mut().unwrap();
6501                transaction.last_edit_at = now;
6502                for (buffer_id, transaction_id) in buffer_transactions {
6503                    transaction
6504                        .buffer_transactions
6505                        .entry(buffer_id)
6506                        .or_insert(transaction_id);
6507                }
6508                true
6509            }
6510        } else {
6511            false
6512        }
6513    }
6514
6515    fn push_transaction<'a, T>(
6516        &mut self,
6517        buffer_transactions: T,
6518        now: Instant,
6519        cx: &Context<MultiBuffer>,
6520    ) where
6521        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6522    {
6523        assert_eq!(self.transaction_depth, 0);
6524        let transaction = Transaction {
6525            id: self.next_transaction_id.tick(),
6526            buffer_transactions: buffer_transactions
6527                .into_iter()
6528                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6529                .collect(),
6530            first_edit_at: now,
6531            last_edit_at: now,
6532            suppress_grouping: false,
6533        };
6534        if !transaction.buffer_transactions.is_empty() {
6535            self.undo_stack.push(transaction);
6536            self.redo_stack.clear();
6537        }
6538    }
6539
6540    fn finalize_last_transaction(&mut self) {
6541        if let Some(transaction) = self.undo_stack.last_mut() {
6542            transaction.suppress_grouping = true;
6543        }
6544    }
6545
6546    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6547        if let Some(ix) = self
6548            .undo_stack
6549            .iter()
6550            .rposition(|transaction| transaction.id == transaction_id)
6551        {
6552            Some(self.undo_stack.remove(ix))
6553        } else if let Some(ix) = self
6554            .redo_stack
6555            .iter()
6556            .rposition(|transaction| transaction.id == transaction_id)
6557        {
6558            Some(self.redo_stack.remove(ix))
6559        } else {
6560            None
6561        }
6562    }
6563
6564    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6565        self.undo_stack
6566            .iter()
6567            .find(|transaction| transaction.id == transaction_id)
6568            .or_else(|| {
6569                self.redo_stack
6570                    .iter()
6571                    .find(|transaction| transaction.id == transaction_id)
6572            })
6573    }
6574
6575    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6576        self.undo_stack
6577            .iter_mut()
6578            .find(|transaction| transaction.id == transaction_id)
6579            .or_else(|| {
6580                self.redo_stack
6581                    .iter_mut()
6582                    .find(|transaction| transaction.id == transaction_id)
6583            })
6584    }
6585
6586    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6587        assert_eq!(self.transaction_depth, 0);
6588        if let Some(transaction) = self.undo_stack.pop() {
6589            self.redo_stack.push(transaction);
6590            self.redo_stack.last_mut()
6591        } else {
6592            None
6593        }
6594    }
6595
6596    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6597        assert_eq!(self.transaction_depth, 0);
6598        if let Some(transaction) = self.redo_stack.pop() {
6599            self.undo_stack.push(transaction);
6600            self.undo_stack.last_mut()
6601        } else {
6602            None
6603        }
6604    }
6605
6606    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6607        let ix = self
6608            .undo_stack
6609            .iter()
6610            .rposition(|transaction| transaction.id == transaction_id)?;
6611        let transaction = self.undo_stack.remove(ix);
6612        self.redo_stack.push(transaction);
6613        self.redo_stack.last()
6614    }
6615
6616    fn group(&mut self) -> Option<TransactionId> {
6617        let mut count = 0;
6618        let mut transactions = self.undo_stack.iter();
6619        if let Some(mut transaction) = transactions.next_back() {
6620            while let Some(prev_transaction) = transactions.next_back() {
6621                if !prev_transaction.suppress_grouping
6622                    && transaction.first_edit_at - prev_transaction.last_edit_at
6623                        <= self.group_interval
6624                {
6625                    transaction = prev_transaction;
6626                    count += 1;
6627                } else {
6628                    break;
6629                }
6630            }
6631        }
6632        self.group_trailing(count)
6633    }
6634
6635    fn group_until(&mut self, transaction_id: TransactionId) {
6636        let mut count = 0;
6637        for transaction in self.undo_stack.iter().rev() {
6638            if transaction.id == transaction_id {
6639                self.group_trailing(count);
6640                break;
6641            } else if transaction.suppress_grouping {
6642                break;
6643            } else {
6644                count += 1;
6645            }
6646        }
6647    }
6648
6649    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6650        let new_len = self.undo_stack.len() - n;
6651        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6652        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6653            if let Some(transaction) = transactions_to_merge.last() {
6654                last_transaction.last_edit_at = transaction.last_edit_at;
6655            }
6656            for to_merge in transactions_to_merge {
6657                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6658                    last_transaction
6659                        .buffer_transactions
6660                        .entry(*buffer_id)
6661                        .or_insert(*transaction_id);
6662                }
6663            }
6664        }
6665
6666        self.undo_stack.truncate(new_len);
6667        self.undo_stack.last().map(|t| t.id)
6668    }
6669}
6670
6671impl Excerpt {
6672    fn new(
6673        id: ExcerptId,
6674        locator: Locator,
6675        buffer_id: BufferId,
6676        buffer: BufferSnapshot,
6677        range: ExcerptRange<text::Anchor>,
6678        has_trailing_newline: bool,
6679    ) -> Self {
6680        Excerpt {
6681            id,
6682            locator,
6683            max_buffer_row: range.context.end.to_point(&buffer).row,
6684            text_summary: buffer
6685                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6686            buffer_id,
6687            buffer,
6688            range,
6689            has_trailing_newline,
6690        }
6691    }
6692
6693    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6694        let content_start = self.range.context.start.to_offset(&self.buffer);
6695        let chunks_start = content_start + range.start;
6696        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6697
6698        let footer_height = if self.has_trailing_newline
6699            && range.start <= self.text_summary.len
6700            && range.end > self.text_summary.len
6701        {
6702            1
6703        } else {
6704            0
6705        };
6706
6707        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6708
6709        ExcerptChunks {
6710            excerpt_id: self.id,
6711            content_chunks,
6712            footer_height,
6713        }
6714    }
6715
6716    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6717        let content_start = self.range.context.start.to_offset(&self.buffer);
6718        let chunks_start = content_start + range.start;
6719        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6720        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6721        excerpt_chunks.footer_height = if self.has_trailing_newline
6722            && range.start <= self.text_summary.len
6723            && range.end > self.text_summary.len
6724        {
6725            1
6726        } else {
6727            0
6728        };
6729    }
6730
6731    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6732        if text_anchor
6733            .cmp(&self.range.context.start, &self.buffer)
6734            .is_lt()
6735        {
6736            self.range.context.start
6737        } else if text_anchor
6738            .cmp(&self.range.context.end, &self.buffer)
6739            .is_gt()
6740        {
6741            self.range.context.end
6742        } else {
6743            text_anchor
6744        }
6745    }
6746
6747    fn contains(&self, anchor: &Anchor) -> bool {
6748        Some(self.buffer_id) == anchor.buffer_id
6749            && self
6750                .range
6751                .context
6752                .start
6753                .cmp(&anchor.text_anchor, &self.buffer)
6754                .is_le()
6755            && self
6756                .range
6757                .context
6758                .end
6759                .cmp(&anchor.text_anchor, &self.buffer)
6760                .is_ge()
6761    }
6762
6763    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6764    fn buffer_start_offset(&self) -> usize {
6765        self.range.context.start.to_offset(&self.buffer)
6766    }
6767
6768    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6769    fn buffer_end_offset(&self) -> usize {
6770        self.buffer_start_offset() + self.text_summary.len
6771    }
6772}
6773
6774impl<'a> MultiBufferExcerpt<'a> {
6775    pub fn id(&self) -> ExcerptId {
6776        self.excerpt.id
6777    }
6778
6779    pub fn buffer_id(&self) -> BufferId {
6780        self.excerpt.buffer_id
6781    }
6782
6783    pub fn start_anchor(&self) -> Anchor {
6784        Anchor {
6785            buffer_id: Some(self.excerpt.buffer_id),
6786            excerpt_id: self.excerpt.id,
6787            text_anchor: self.excerpt.range.context.start,
6788            diff_base_anchor: None,
6789        }
6790    }
6791
6792    pub fn end_anchor(&self) -> Anchor {
6793        Anchor {
6794            buffer_id: Some(self.excerpt.buffer_id),
6795            excerpt_id: self.excerpt.id,
6796            text_anchor: self.excerpt.range.context.end,
6797            diff_base_anchor: None,
6798        }
6799    }
6800
6801    pub fn buffer(&self) -> &'a BufferSnapshot {
6802        &self.excerpt.buffer
6803    }
6804
6805    pub fn buffer_range(&self) -> Range<usize> {
6806        self.buffer_offset
6807            ..self
6808                .excerpt
6809                .range
6810                .context
6811                .end
6812                .to_offset(&self.excerpt.buffer.text)
6813    }
6814
6815    pub fn start_offset(&self) -> usize {
6816        self.offset
6817    }
6818
6819    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6820    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6821        self.map_range_to_buffer(offset..offset).start
6822    }
6823
6824    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6825    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6826        self.diff_transforms
6827            .seek(&OutputDimension(range.start), Bias::Right, &());
6828        let start = self.map_offset_to_buffer_internal(range.start);
6829        let end = if range.end > range.start {
6830            self.diff_transforms
6831                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6832            self.map_offset_to_buffer_internal(range.end)
6833        } else {
6834            start
6835        };
6836        start..end
6837    }
6838
6839    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6840        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6841        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6842            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6843        };
6844        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6845        self.buffer_offset + offset_in_excerpt
6846    }
6847
6848    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6849    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6850        self.map_range_from_buffer(buffer_offset..buffer_offset)
6851            .start
6852    }
6853
6854    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6855    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6856        if buffer_range.start < self.buffer_offset {
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 = buffer_range.start - self.buffer_offset;
6861        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6862        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6863        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6864            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6865            return buffer_range;
6866        }
6867        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6868        let start = self.diff_transforms.start().0 .0 + overshoot;
6869
6870        let end = if buffer_range.end > buffer_range.start {
6871            let overshoot = buffer_range.end - self.buffer_offset;
6872            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6873            self.diff_transforms
6874                .seek_forward(&excerpt_offset, Bias::Right, &());
6875            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6876            self.diff_transforms.start().0 .0 + overshoot
6877        } else {
6878            start
6879        };
6880
6881        start..end
6882    }
6883
6884    /// Returns true if the entirety of the given range is in the buffer's excerpt
6885    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6886        range.start >= self.excerpt.buffer_start_offset()
6887            && range.end <= self.excerpt.buffer_end_offset()
6888    }
6889
6890    pub fn max_buffer_row(&self) -> u32 {
6891        self.excerpt.max_buffer_row
6892    }
6893}
6894
6895impl ExcerptId {
6896    pub fn min() -> Self {
6897        Self(0)
6898    }
6899
6900    pub fn max() -> Self {
6901        Self(usize::MAX)
6902    }
6903
6904    pub fn to_proto(&self) -> u64 {
6905        self.0 as _
6906    }
6907
6908    pub fn from_proto(proto: u64) -> Self {
6909        Self(proto as _)
6910    }
6911
6912    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6913        let a = snapshot.excerpt_locator_for_id(*self);
6914        let b = snapshot.excerpt_locator_for_id(*other);
6915        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6916    }
6917}
6918
6919impl From<ExcerptId> for usize {
6920    fn from(val: ExcerptId) -> Self {
6921        val.0
6922    }
6923}
6924
6925impl fmt::Debug for Excerpt {
6926    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6927        f.debug_struct("Excerpt")
6928            .field("id", &self.id)
6929            .field("locator", &self.locator)
6930            .field("buffer_id", &self.buffer_id)
6931            .field("range", &self.range)
6932            .field("text_summary", &self.text_summary)
6933            .field("has_trailing_newline", &self.has_trailing_newline)
6934            .finish()
6935    }
6936}
6937
6938impl sum_tree::Item for Excerpt {
6939    type Summary = ExcerptSummary;
6940
6941    fn summary(&self, _cx: &()) -> Self::Summary {
6942        let mut text = self.text_summary;
6943        if self.has_trailing_newline {
6944            text += TextSummary::from("\n");
6945        }
6946        ExcerptSummary {
6947            excerpt_id: self.id,
6948            excerpt_locator: self.locator.clone(),
6949            widest_line_number: self.max_buffer_row,
6950            text,
6951        }
6952    }
6953}
6954
6955impl sum_tree::Item for ExcerptIdMapping {
6956    type Summary = ExcerptId;
6957
6958    fn summary(&self, _cx: &()) -> Self::Summary {
6959        self.id
6960    }
6961}
6962
6963impl sum_tree::KeyedItem for ExcerptIdMapping {
6964    type Key = ExcerptId;
6965
6966    fn key(&self) -> Self::Key {
6967        self.id
6968    }
6969}
6970
6971impl DiffTransform {
6972    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6973        match self {
6974            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6975            DiffTransform::BufferContent {
6976                inserted_hunk_info, ..
6977            } => *inserted_hunk_info,
6978        }
6979    }
6980}
6981
6982impl sum_tree::Item for DiffTransform {
6983    type Summary = DiffTransformSummary;
6984
6985    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6986        match self {
6987            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6988                input: *summary,
6989                output: *summary,
6990            },
6991            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6992                input: TextSummary::default(),
6993                output: *summary,
6994            },
6995        }
6996    }
6997}
6998
6999impl DiffTransformSummary {
7000    fn excerpt_len(&self) -> ExcerptOffset {
7001        ExcerptOffset::new(self.input.len)
7002    }
7003}
7004
7005impl sum_tree::Summary for DiffTransformSummary {
7006    type Context = ();
7007
7008    fn zero(_: &Self::Context) -> Self {
7009        DiffTransformSummary {
7010            input: TextSummary::default(),
7011            output: TextSummary::default(),
7012        }
7013    }
7014
7015    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7016        self.input += &summary.input;
7017        self.output += &summary.output;
7018    }
7019}
7020
7021impl sum_tree::Summary for ExcerptId {
7022    type Context = ();
7023
7024    fn zero(_cx: &()) -> Self {
7025        Default::default()
7026    }
7027
7028    fn add_summary(&mut self, other: &Self, _: &()) {
7029        *self = *other;
7030    }
7031}
7032
7033impl sum_tree::Summary for ExcerptSummary {
7034    type Context = ();
7035
7036    fn zero(_cx: &()) -> Self {
7037        Default::default()
7038    }
7039
7040    fn add_summary(&mut self, summary: &Self, _: &()) {
7041        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7042        self.excerpt_locator = summary.excerpt_locator.clone();
7043        self.text.add_summary(&summary.text, &());
7044        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7045    }
7046}
7047
7048impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7049    fn zero(_cx: &()) -> Self {
7050        Default::default()
7051    }
7052
7053    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7054        self.value += summary.text.len;
7055    }
7056}
7057
7058impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7059    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7060        Ord::cmp(&self.value, &cursor_location.text.len)
7061    }
7062}
7063
7064impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7065    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7066        Ord::cmp(&Some(self), cursor_location)
7067    }
7068}
7069
7070impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7071    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7072        Ord::cmp(self, &cursor_location.excerpt_locator)
7073    }
7074}
7075
7076impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7077    fn zero(_cx: &()) -> Self {
7078        Default::default()
7079    }
7080
7081    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7082        self.value += summary.text.lines;
7083    }
7084}
7085
7086impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7087    for ExcerptDimension<D>
7088{
7089    fn zero(_: &()) -> Self {
7090        ExcerptDimension(D::default())
7091    }
7092
7093    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7094        self.0.add_assign(&D::from_text_summary(&summary.text))
7095    }
7096}
7097
7098impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7099    fn zero(_cx: &()) -> Self {
7100        Default::default()
7101    }
7102
7103    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7104        *self = Some(&summary.excerpt_locator);
7105    }
7106}
7107
7108impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7109    fn zero(_cx: &()) -> Self {
7110        Default::default()
7111    }
7112
7113    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7114        *self = Some(summary.excerpt_id);
7115    }
7116}
7117
7118#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7119struct ExcerptDimension<T>(T);
7120
7121#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7122struct OutputDimension<T>(T);
7123
7124impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7125    fn zero(_: &()) -> Self {
7126        ExcerptOffset::new(0)
7127    }
7128
7129    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7130        self.value += summary.input.len;
7131    }
7132}
7133
7134impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7135    fn zero(_: &()) -> Self {
7136        ExcerptPoint::new(0, 0)
7137    }
7138
7139    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7140        self.value += summary.input.lines;
7141    }
7142}
7143
7144impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7145    for ExcerptDimension<D>
7146{
7147    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7148        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7149    }
7150}
7151
7152impl<D: TextDimension + Ord>
7153    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7154    for ExcerptDimension<D>
7155{
7156    fn cmp(
7157        &self,
7158        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7159        _: &(),
7160    ) -> cmp::Ordering {
7161        Ord::cmp(&self.0, &cursor_location.1 .0)
7162    }
7163}
7164
7165impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7166    fn zero(_: &()) -> Self {
7167        ExcerptDimension(D::default())
7168    }
7169
7170    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7171        self.0.add_assign(&D::from_text_summary(&summary.input))
7172    }
7173}
7174
7175impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7176    fn zero(_: &()) -> Self {
7177        OutputDimension(D::default())
7178    }
7179
7180    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7181        self.0.add_assign(&D::from_text_summary(&summary.output))
7182    }
7183}
7184
7185impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7186    fn zero(_: &()) -> Self {
7187        TextSummary::default()
7188    }
7189
7190    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7191        *self += summary.output
7192    }
7193}
7194
7195impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7196    fn zero(_: &()) -> Self {
7197        0
7198    }
7199
7200    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7201        *self += summary.output.len
7202    }
7203}
7204
7205impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7206    fn zero(_: &()) -> Self {
7207        Point::new(0, 0)
7208    }
7209
7210    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7211        *self += summary.output.lines
7212    }
7213}
7214
7215impl MultiBufferRows<'_> {
7216    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7217        self.point = Point::new(row, 0);
7218        self.cursor.seek(&self.point);
7219    }
7220}
7221
7222impl Iterator for MultiBufferRows<'_> {
7223    type Item = RowInfo;
7224
7225    fn next(&mut self) -> Option<Self::Item> {
7226        if self.is_empty && self.point.row == 0 {
7227            self.point += Point::new(1, 0);
7228            return Some(RowInfo {
7229                buffer_id: None,
7230                buffer_row: Some(0),
7231                multibuffer_row: Some(MultiBufferRow(0)),
7232                diff_status: None,
7233                expand_info: None,
7234            });
7235        }
7236
7237        let mut region = self.cursor.region()?;
7238        while self.point >= region.range.end {
7239            self.cursor.next();
7240            if let Some(next_region) = self.cursor.region() {
7241                region = next_region;
7242            } else {
7243                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7244                    let multibuffer_row = MultiBufferRow(self.point.row);
7245                    let last_excerpt = self
7246                        .cursor
7247                        .excerpts
7248                        .item()
7249                        .or(self.cursor.excerpts.prev_item())?;
7250                    let last_row = last_excerpt
7251                        .range
7252                        .context
7253                        .end
7254                        .to_point(&last_excerpt.buffer)
7255                        .row;
7256
7257                    let first_row = last_excerpt
7258                        .range
7259                        .context
7260                        .start
7261                        .to_point(&last_excerpt.buffer)
7262                        .row;
7263
7264                    let expand_info = if self.is_singleton {
7265                        None
7266                    } else {
7267                        let needs_expand_up = first_row == last_row
7268                            && last_row > 0
7269                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7270                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7271
7272                        if needs_expand_up && needs_expand_down {
7273                            Some(ExpandExcerptDirection::UpAndDown)
7274                        } else if needs_expand_up {
7275                            Some(ExpandExcerptDirection::Up)
7276                        } else if needs_expand_down {
7277                            Some(ExpandExcerptDirection::Down)
7278                        } else {
7279                            None
7280                        }
7281                        .map(|direction| ExpandInfo {
7282                            direction,
7283                            excerpt_id: last_excerpt.id,
7284                        })
7285                    };
7286                    self.point += Point::new(1, 0);
7287                    return Some(RowInfo {
7288                        buffer_id: Some(last_excerpt.buffer_id),
7289                        buffer_row: Some(last_row),
7290                        multibuffer_row: Some(multibuffer_row),
7291                        diff_status: None,
7292                        expand_info,
7293                    });
7294                } else {
7295                    return None;
7296                }
7297            };
7298        }
7299
7300        let overshoot = self.point - region.range.start;
7301        let buffer_point = region.buffer_range.start + overshoot;
7302        let expand_info = if self.is_singleton {
7303            None
7304        } else {
7305            let needs_expand_up = self.point.row == region.range.start.row
7306                && self.cursor.is_at_start_of_excerpt()
7307                && buffer_point.row > 0;
7308            let needs_expand_down = (region.excerpt.has_trailing_newline
7309                && self.point.row + 1 == region.range.end.row
7310                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7311                && self.cursor.is_at_end_of_excerpt()
7312                && buffer_point.row < region.buffer.max_point().row;
7313
7314            if needs_expand_up && needs_expand_down {
7315                Some(ExpandExcerptDirection::UpAndDown)
7316            } else if needs_expand_up {
7317                Some(ExpandExcerptDirection::Up)
7318            } else if needs_expand_down {
7319                Some(ExpandExcerptDirection::Down)
7320            } else {
7321                None
7322            }
7323            .map(|direction| ExpandInfo {
7324                direction,
7325                excerpt_id: region.excerpt.id,
7326            })
7327        };
7328
7329        let result = Some(RowInfo {
7330            buffer_id: Some(region.buffer.remote_id()),
7331            buffer_row: Some(buffer_point.row),
7332            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7333            diff_status: region
7334                .diff_hunk_status
7335                .filter(|_| self.point < region.range.end),
7336            expand_info,
7337        });
7338        self.point += Point::new(1, 0);
7339        result
7340    }
7341}
7342
7343impl<'a> MultiBufferChunks<'a> {
7344    pub fn offset(&self) -> usize {
7345        self.range.start
7346    }
7347
7348    pub fn seek(&mut self, range: Range<usize>) {
7349        self.diff_transforms.seek(&range.end, Bias::Right, &());
7350        let mut excerpt_end = self.diff_transforms.start().1;
7351        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7352            let overshoot = range.end - self.diff_transforms.start().0;
7353            excerpt_end.value += overshoot;
7354        }
7355
7356        self.diff_transforms.seek(&range.start, Bias::Right, &());
7357        let mut excerpt_start = self.diff_transforms.start().1;
7358        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7359            let overshoot = range.start - self.diff_transforms.start().0;
7360            excerpt_start.value += overshoot;
7361        }
7362
7363        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7364        self.buffer_chunk.take();
7365        self.range = range;
7366    }
7367
7368    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7369        self.excerpt_offset_range = new_range.clone();
7370        self.excerpts.seek(&new_range.start, Bias::Right, &());
7371        if let Some(excerpt) = self.excerpts.item() {
7372            let excerpt_start = *self.excerpts.start();
7373            if let Some(excerpt_chunks) = self
7374                .excerpt_chunks
7375                .as_mut()
7376                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7377            {
7378                excerpt.seek_chunks(
7379                    excerpt_chunks,
7380                    (self.excerpt_offset_range.start - excerpt_start).value
7381                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7382                );
7383            } else {
7384                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7385                    (self.excerpt_offset_range.start - excerpt_start).value
7386                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7387                    self.language_aware,
7388                ));
7389            }
7390        } else {
7391            self.excerpt_chunks = None;
7392        }
7393    }
7394
7395    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7396        loop {
7397            if self.excerpt_offset_range.is_empty() {
7398                return None;
7399            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7400                self.excerpt_offset_range.start.value += chunk.text.len();
7401                return Some(chunk);
7402            } else {
7403                self.excerpts.next(&());
7404                let excerpt = self.excerpts.item()?;
7405                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7406                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7407                    self.language_aware,
7408                ));
7409            }
7410        }
7411    }
7412}
7413
7414impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7415    type Item = &'a str;
7416
7417    fn next(&mut self) -> Option<Self::Item> {
7418        let mut region = self.cursor.region()?;
7419        if self.offset == region.range.start {
7420            self.cursor.prev();
7421            region = self.cursor.region()?;
7422            let start_overshoot = self.start.saturating_sub(region.range.start);
7423            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7424                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7425            ));
7426        }
7427
7428        if self.offset == region.range.end && region.has_trailing_newline {
7429            self.offset -= 1;
7430            Some("\n")
7431        } else {
7432            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7433            self.offset -= chunk.len();
7434            Some(chunk)
7435        }
7436    }
7437}
7438
7439impl<'a> Iterator for MultiBufferChunks<'a> {
7440    type Item = Chunk<'a>;
7441
7442    fn next(&mut self) -> Option<Chunk<'a>> {
7443        if self.range.start >= self.range.end {
7444            return None;
7445        }
7446        if self.range.start == self.diff_transforms.end(&()).0 {
7447            self.diff_transforms.next(&());
7448        }
7449
7450        let diff_transform_start = self.diff_transforms.start().0;
7451        let diff_transform_end = self.diff_transforms.end(&()).0;
7452        debug_assert!(self.range.start < diff_transform_end);
7453
7454        let diff_transform = self.diff_transforms.item()?;
7455        match diff_transform {
7456            DiffTransform::BufferContent { .. } => {
7457                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7458                    chunk
7459                } else {
7460                    let chunk = self.next_excerpt_chunk().unwrap();
7461                    self.buffer_chunk.insert(chunk)
7462                };
7463
7464                let chunk_end = self.range.start + chunk.text.len();
7465                let diff_transform_end = diff_transform_end.min(self.range.end);
7466
7467                if diff_transform_end < chunk_end {
7468                    let (before, after) =
7469                        chunk.text.split_at(diff_transform_end - self.range.start);
7470                    self.range.start = diff_transform_end;
7471                    chunk.text = after;
7472                    Some(Chunk {
7473                        text: before,
7474                        ..chunk.clone()
7475                    })
7476                } else {
7477                    self.range.start = chunk_end;
7478                    self.buffer_chunk.take()
7479                }
7480            }
7481            DiffTransform::DeletedHunk {
7482                buffer_id,
7483                base_text_byte_range,
7484                has_trailing_newline,
7485                ..
7486            } => {
7487                let base_text_start =
7488                    base_text_byte_range.start + self.range.start - diff_transform_start;
7489                let base_text_end =
7490                    base_text_byte_range.start + self.range.end - diff_transform_start;
7491                let base_text_end = base_text_end.min(base_text_byte_range.end);
7492
7493                let mut chunks = if let Some((_, mut chunks)) = self
7494                    .diff_base_chunks
7495                    .take()
7496                    .filter(|(id, _)| id == buffer_id)
7497                {
7498                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7499                    {
7500                        chunks.seek(base_text_start..base_text_end);
7501                    }
7502                    chunks
7503                } else {
7504                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7505                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7506                };
7507
7508                let chunk = if let Some(chunk) = chunks.next() {
7509                    self.range.start += chunk.text.len();
7510                    self.diff_base_chunks = Some((*buffer_id, chunks));
7511                    chunk
7512                } else {
7513                    debug_assert!(has_trailing_newline);
7514                    self.range.start += "\n".len();
7515                    Chunk {
7516                        text: "\n",
7517                        ..Default::default()
7518                    }
7519                };
7520                Some(chunk)
7521            }
7522        }
7523    }
7524}
7525
7526impl MultiBufferBytes<'_> {
7527    fn consume(&mut self, len: usize) {
7528        self.range.start += len;
7529        self.chunk = &self.chunk[len..];
7530
7531        if !self.range.is_empty() && self.chunk.is_empty() {
7532            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7533                self.chunk = chunk;
7534            } else if self.has_trailing_newline {
7535                self.has_trailing_newline = false;
7536                self.chunk = b"\n";
7537            } else {
7538                self.cursor.next();
7539                if let Some(region) = self.cursor.region() {
7540                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7541                        region.buffer_range.start
7542                            ..(region.buffer_range.start + self.range.end - region.range.start)
7543                                .min(region.buffer_range.end),
7544                    );
7545                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7546                    self.excerpt_bytes = Some(excerpt_bytes);
7547                    self.has_trailing_newline =
7548                        region.has_trailing_newline && self.range.end >= region.range.end;
7549                    if self.chunk.is_empty() && self.has_trailing_newline {
7550                        self.has_trailing_newline = false;
7551                        self.chunk = b"\n";
7552                    }
7553                }
7554            }
7555        }
7556    }
7557}
7558
7559impl<'a> Iterator for MultiBufferBytes<'a> {
7560    type Item = &'a [u8];
7561
7562    fn next(&mut self) -> Option<Self::Item> {
7563        let chunk = self.chunk;
7564        if chunk.is_empty() {
7565            None
7566        } else {
7567            self.consume(chunk.len());
7568            Some(chunk)
7569        }
7570    }
7571}
7572
7573impl io::Read for MultiBufferBytes<'_> {
7574    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7575        let len = cmp::min(buf.len(), self.chunk.len());
7576        buf[..len].copy_from_slice(&self.chunk[..len]);
7577        if len > 0 {
7578            self.consume(len);
7579        }
7580        Ok(len)
7581    }
7582}
7583
7584impl io::Read for ReversedMultiBufferBytes<'_> {
7585    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7586        let len = cmp::min(buf.len(), self.chunk.len());
7587        buf[..len].copy_from_slice(&self.chunk[..len]);
7588        buf[..len].reverse();
7589        if len > 0 {
7590            self.range.end -= len;
7591            self.chunk = &self.chunk[..self.chunk.len() - len];
7592            if !self.range.is_empty() && self.chunk.is_empty() {
7593                if let Some(chunk) = self.chunks.next() {
7594                    self.chunk = chunk.as_bytes();
7595                }
7596            }
7597        }
7598        Ok(len)
7599    }
7600}
7601
7602impl<'a> Iterator for ExcerptChunks<'a> {
7603    type Item = Chunk<'a>;
7604
7605    fn next(&mut self) -> Option<Self::Item> {
7606        if let Some(chunk) = self.content_chunks.next() {
7607            return Some(chunk);
7608        }
7609
7610        if self.footer_height > 0 {
7611            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7612            self.footer_height = 0;
7613            return Some(Chunk {
7614                text,
7615                ..Default::default()
7616            });
7617        }
7618
7619        None
7620    }
7621}
7622
7623impl ToOffset for Point {
7624    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7625        snapshot.point_to_offset(*self)
7626    }
7627}
7628
7629impl ToOffset for usize {
7630    #[track_caller]
7631    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7632        assert!(*self <= snapshot.len(), "offset is out of range");
7633        *self
7634    }
7635}
7636
7637impl ToOffset for OffsetUtf16 {
7638    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7639        snapshot.offset_utf16_to_offset(*self)
7640    }
7641}
7642
7643impl ToOffset for PointUtf16 {
7644    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7645        snapshot.point_utf16_to_offset(*self)
7646    }
7647}
7648
7649impl ToOffsetUtf16 for OffsetUtf16 {
7650    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7651        *self
7652    }
7653}
7654
7655impl ToOffsetUtf16 for usize {
7656    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7657        snapshot.offset_to_offset_utf16(*self)
7658    }
7659}
7660
7661impl ToPoint for usize {
7662    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7663        snapshot.offset_to_point(*self)
7664    }
7665}
7666
7667impl ToPoint for Point {
7668    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7669        *self
7670    }
7671}
7672
7673impl ToPointUtf16 for usize {
7674    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7675        snapshot.offset_to_point_utf16(*self)
7676    }
7677}
7678
7679impl ToPointUtf16 for Point {
7680    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7681        snapshot.point_to_point_utf16(*self)
7682    }
7683}
7684
7685impl ToPointUtf16 for PointUtf16 {
7686    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7687        *self
7688    }
7689}
7690
7691impl From<ExcerptId> for EntityId {
7692    fn from(id: ExcerptId) -> Self {
7693        EntityId::from(id.0 as u64)
7694    }
7695}
7696
7697pub fn build_excerpt_ranges<T>(
7698    buffer: &BufferSnapshot,
7699    ranges: &[Range<T>],
7700    context_line_count: u32,
7701) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7702where
7703    T: text::ToPoint,
7704{
7705    let max_point = buffer.max_point();
7706    let mut range_counts = Vec::new();
7707    let mut excerpt_ranges = Vec::new();
7708    let mut range_iter = ranges
7709        .iter()
7710        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7711        .peekable();
7712    while let Some(range) = range_iter.next() {
7713        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7714        let row = (range.end.row + context_line_count).min(max_point.row);
7715        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7716
7717        let mut ranges_in_excerpt = 1;
7718
7719        while let Some(next_range) = range_iter.peek() {
7720            if next_range.start.row <= excerpt_end.row + context_line_count {
7721                let row = (next_range.end.row + context_line_count).min(max_point.row);
7722                excerpt_end = Point::new(row, buffer.line_len(row));
7723
7724                ranges_in_excerpt += 1;
7725                range_iter.next();
7726            } else {
7727                break;
7728            }
7729        }
7730
7731        excerpt_ranges.push(ExcerptRange {
7732            context: excerpt_start..excerpt_end,
7733            primary: Some(range),
7734        });
7735        range_counts.push(ranges_in_excerpt);
7736    }
7737
7738    (excerpt_ranges, range_counts)
7739}