multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  47use text::{
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50    BufferId, Edit, LineIndent, TextSummary,
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    diffs: HashMap<BufferId, DiffState>,
  72    all_diff_hunks_expanded: bool,
  73    subscriptions: Topic,
  74    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  75    singleton: bool,
  76    history: History,
  77    title: Option<String>,
  78    capability: Capability,
  79}
  80
  81#[derive(Clone, Debug, PartialEq, Eq)]
  82pub enum Event {
  83    ExcerptsAdded {
  84        buffer: Entity<Buffer>,
  85        predecessor: ExcerptId,
  86        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  87    },
  88    ExcerptsRemoved {
  89        ids: Vec<ExcerptId>,
  90    },
  91    ExcerptsExpanded {
  92        ids: Vec<ExcerptId>,
  93    },
  94    ExcerptsEdited {
  95        ids: Vec<ExcerptId>,
  96    },
  97    DiffHunksToggled,
  98    Edited {
  99        singleton_buffer_edited: bool,
 100        edited_buffer: Option<Entity<Buffer>>,
 101    },
 102    TransactionUndone {
 103        transaction_id: TransactionId,
 104    },
 105    Reloaded,
 106    ReloadNeeded,
 107
 108    LanguageChanged(BufferId),
 109    CapabilityChanged,
 110    Reparsed(BufferId),
 111    Saved,
 112    FileHandleChanged,
 113    Closed,
 114    Discarded,
 115    DirtyChanged,
 116    DiagnosticsUpdated,
 117}
 118
 119/// A diff hunk, representing a range of consequent lines in a multibuffer.
 120#[derive(Debug, Clone, PartialEq, Eq)]
 121pub struct MultiBufferDiffHunk {
 122    /// The row range in the multibuffer where this diff hunk appears.
 123    pub row_range: Range<MultiBufferRow>,
 124    /// The buffer ID that this hunk belongs to.
 125    pub buffer_id: BufferId,
 126    /// The range of the underlying buffer that this hunk corresponds to.
 127    pub buffer_range: Range<text::Anchor>,
 128    /// The excerpt that contains the diff hunk.
 129    pub excerpt_id: ExcerptId,
 130    /// The range within the buffer's diff base that this hunk corresponds to.
 131    pub diff_base_byte_range: Range<usize>,
 132    /// Whether or not this hunk also appears in the 'secondary diff'.
 133    pub secondary_status: DiffHunkSecondaryStatus,
 134    pub secondary_diff_base_byte_range: Option<Range<usize>>,
 135}
 136
 137impl MultiBufferDiffHunk {
 138    pub fn status(&self) -> DiffHunkStatus {
 139        let kind = if self.buffer_range.start == self.buffer_range.end {
 140            DiffHunkStatusKind::Deleted
 141        } else if self.diff_base_byte_range.is_empty() {
 142            DiffHunkStatusKind::Added
 143        } else {
 144            DiffHunkStatusKind::Modified
 145        };
 146        DiffHunkStatus {
 147            kind,
 148            secondary: self.secondary_status,
 149        }
 150    }
 151}
 152
 153#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 154pub struct PathKey {
 155    namespace: &'static str,
 156    path: Arc<Path>,
 157}
 158
 159impl PathKey {
 160    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 161        Self { namespace, path }
 162    }
 163}
 164
 165pub type MultiBufferPoint = Point;
 166type ExcerptOffset = TypedOffset<Excerpt>;
 167type ExcerptPoint = TypedPoint<Excerpt>;
 168
 169#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 170#[serde(transparent)]
 171pub struct MultiBufferRow(pub u32);
 172
 173impl MultiBufferRow {
 174    pub const MIN: Self = Self(0);
 175    pub const MAX: Self = Self(u32::MAX);
 176}
 177
 178impl std::ops::Add<usize> for MultiBufferRow {
 179    type Output = Self;
 180
 181    fn add(self, rhs: usize) -> Self::Output {
 182        MultiBufferRow(self.0 + rhs as u32)
 183    }
 184}
 185
 186#[derive(Clone)]
 187struct History {
 188    next_transaction_id: TransactionId,
 189    undo_stack: Vec<Transaction>,
 190    redo_stack: Vec<Transaction>,
 191    transaction_depth: usize,
 192    group_interval: Duration,
 193}
 194
 195#[derive(Clone)]
 196struct Transaction {
 197    id: TransactionId,
 198    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 199    first_edit_at: Instant,
 200    last_edit_at: Instant,
 201    suppress_grouping: bool,
 202}
 203
 204pub trait ToOffset: 'static + fmt::Debug {
 205    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 206}
 207
 208pub trait ToOffsetUtf16: 'static + fmt::Debug {
 209    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 210}
 211
 212pub trait ToPoint: 'static + fmt::Debug {
 213    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 214}
 215
 216pub trait ToPointUtf16: 'static + fmt::Debug {
 217    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 218}
 219
 220struct BufferState {
 221    buffer: Entity<Buffer>,
 222    last_version: clock::Global,
 223    last_non_text_state_update_count: usize,
 224    excerpts: Vec<Locator>,
 225    _subscriptions: [gpui::Subscription; 2],
 226}
 227
 228struct DiffState {
 229    diff: Entity<BufferDiff>,
 230    _subscription: gpui::Subscription,
 231}
 232
 233impl DiffState {
 234    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 235        DiffState {
 236            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 237                BufferDiffEvent::DiffChanged { changed_range } => {
 238                    let changed_range = if let Some(changed_range) = changed_range {
 239                        changed_range.clone()
 240                    } else if diff.read(cx).base_text().is_none() && this.all_diff_hunks_expanded {
 241                        text::Anchor::MIN..text::Anchor::MAX
 242                    } else {
 243                        return;
 244                    };
 245                    this.buffer_diff_changed(diff, changed_range, cx)
 246                }
 247                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 248            }),
 249            diff,
 250        }
 251    }
 252}
 253
 254/// The contents of a [`MultiBuffer`] at a single point in time.
 255#[derive(Clone, Default)]
 256pub struct MultiBufferSnapshot {
 257    singleton: bool,
 258    excerpts: SumTree<Excerpt>,
 259    excerpt_ids: SumTree<ExcerptIdMapping>,
 260    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 261    diff_transforms: SumTree<DiffTransform>,
 262    trailing_excerpt_update_count: usize,
 263    non_text_state_update_count: usize,
 264    edit_count: usize,
 265    is_dirty: bool,
 266    has_deleted_file: bool,
 267    has_conflict: bool,
 268    show_headers: bool,
 269}
 270
 271#[derive(Debug, Clone)]
 272enum DiffTransform {
 273    BufferContent {
 274        summary: TextSummary,
 275        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 276    },
 277    DeletedHunk {
 278        summary: TextSummary,
 279        buffer_id: BufferId,
 280        hunk_info: DiffTransformHunkInfo,
 281        base_text_byte_range: Range<usize>,
 282        has_trailing_newline: bool,
 283    },
 284}
 285
 286#[derive(Clone, Copy, Debug)]
 287struct DiffTransformHunkInfo {
 288    excerpt_id: ExcerptId,
 289    hunk_start_anchor: text::Anchor,
 290    hunk_secondary_status: DiffHunkSecondaryStatus,
 291}
 292
 293impl Eq for DiffTransformHunkInfo {}
 294
 295impl PartialEq for DiffTransformHunkInfo {
 296    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 297        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 298    }
 299}
 300
 301impl std::hash::Hash for DiffTransformHunkInfo {
 302    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 303        self.excerpt_id.hash(state);
 304        self.hunk_start_anchor.hash(state);
 305    }
 306}
 307
 308#[derive(Clone)]
 309pub struct ExcerptInfo {
 310    pub id: ExcerptId,
 311    pub buffer: BufferSnapshot,
 312    pub buffer_id: BufferId,
 313    pub range: ExcerptRange<text::Anchor>,
 314    pub end_row: MultiBufferRow,
 315}
 316
 317impl std::fmt::Debug for ExcerptInfo {
 318    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 319        f.debug_struct(type_name::<Self>())
 320            .field("id", &self.id)
 321            .field("buffer_id", &self.buffer_id)
 322            .field("path", &self.buffer.file().map(|f| f.path()))
 323            .field("range", &self.range)
 324            .finish()
 325    }
 326}
 327
 328/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 329#[derive(Debug)]
 330pub struct ExcerptBoundary {
 331    pub prev: Option<ExcerptInfo>,
 332    pub next: Option<ExcerptInfo>,
 333    /// The row in the `MultiBuffer` where the boundary is located
 334    pub row: MultiBufferRow,
 335}
 336
 337impl ExcerptBoundary {
 338    pub fn starts_new_buffer(&self) -> bool {
 339        match (self.prev.as_ref(), self.next.as_ref()) {
 340            (None, _) => true,
 341            (Some(_), None) => false,
 342            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 343        }
 344    }
 345}
 346
 347#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 348pub struct RowInfo {
 349    pub buffer_id: Option<BufferId>,
 350    pub buffer_row: Option<u32>,
 351    pub multibuffer_row: Option<MultiBufferRow>,
 352    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 353}
 354
 355/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 356#[derive(Clone)]
 357struct Excerpt {
 358    /// The unique identifier for this excerpt
 359    id: ExcerptId,
 360    /// The location of the excerpt in the [`MultiBuffer`]
 361    locator: Locator,
 362    /// The buffer being excerpted
 363    buffer_id: BufferId,
 364    /// A snapshot of the buffer being excerpted
 365    buffer: BufferSnapshot,
 366    /// The range of the buffer to be shown in the excerpt
 367    range: ExcerptRange<text::Anchor>,
 368    /// The last row in the excerpted slice of the buffer
 369    max_buffer_row: BufferRow,
 370    /// A summary of the text in the excerpt
 371    text_summary: TextSummary,
 372    has_trailing_newline: bool,
 373}
 374
 375/// A public view into an `Excerpt` in a [`MultiBuffer`].
 376///
 377/// Contains methods for getting the [`Buffer`] of the excerpt,
 378/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 379#[derive(Clone)]
 380pub struct MultiBufferExcerpt<'a> {
 381    excerpt: &'a Excerpt,
 382    diff_transforms:
 383        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 384    offset: usize,
 385    excerpt_offset: ExcerptDimension<usize>,
 386    buffer_offset: usize,
 387}
 388
 389#[derive(Clone, Debug)]
 390struct ExcerptIdMapping {
 391    id: ExcerptId,
 392    locator: Locator,
 393}
 394
 395/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 396/// These ranges are relative to the buffer itself
 397#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 398pub struct ExcerptRange<T> {
 399    /// The full range of text to be shown in the excerpt.
 400    pub context: Range<T>,
 401    /// The primary range of text to be highlighted in the excerpt.
 402    /// In a multi-buffer search, this would be the text that matched the search
 403    pub primary: Option<Range<T>>,
 404}
 405
 406#[derive(Clone, Debug, Default)]
 407pub struct ExcerptSummary {
 408    excerpt_id: ExcerptId,
 409    /// The location of the last [`Excerpt`] being summarized
 410    excerpt_locator: Locator,
 411    widest_line_number: u32,
 412    text: TextSummary,
 413}
 414
 415#[derive(Debug, Clone)]
 416pub struct DiffTransformSummary {
 417    input: TextSummary,
 418    output: TextSummary,
 419}
 420
 421#[derive(Clone)]
 422pub struct MultiBufferRows<'a> {
 423    point: Point,
 424    is_empty: bool,
 425    cursor: MultiBufferCursor<'a, Point>,
 426}
 427
 428pub struct MultiBufferChunks<'a> {
 429    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 430    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 431    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 432    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 433    buffer_chunk: Option<Chunk<'a>>,
 434    range: Range<usize>,
 435    excerpt_offset_range: Range<ExcerptOffset>,
 436    excerpt_chunks: Option<ExcerptChunks<'a>>,
 437    language_aware: bool,
 438}
 439
 440pub struct ReversedMultiBufferChunks<'a> {
 441    cursor: MultiBufferCursor<'a, usize>,
 442    current_chunks: Option<rope::Chunks<'a>>,
 443    start: usize,
 444    offset: usize,
 445}
 446
 447pub struct MultiBufferBytes<'a> {
 448    range: Range<usize>,
 449    cursor: MultiBufferCursor<'a, usize>,
 450    excerpt_bytes: Option<text::Bytes<'a>>,
 451    has_trailing_newline: bool,
 452    chunk: &'a [u8],
 453}
 454
 455pub struct ReversedMultiBufferBytes<'a> {
 456    range: Range<usize>,
 457    chunks: ReversedMultiBufferChunks<'a>,
 458    chunk: &'a [u8],
 459}
 460
 461#[derive(Clone)]
 462struct MultiBufferCursor<'a, D: TextDimension> {
 463    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 464    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 465    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 466    cached_region: Option<MultiBufferRegion<'a, D>>,
 467}
 468
 469#[derive(Clone)]
 470struct MultiBufferRegion<'a, D: TextDimension> {
 471    buffer: &'a BufferSnapshot,
 472    is_main_buffer: bool,
 473    diff_hunk_status: Option<DiffHunkStatus>,
 474    excerpt: &'a Excerpt,
 475    buffer_range: Range<D>,
 476    range: Range<D>,
 477    has_trailing_newline: bool,
 478}
 479
 480struct ExcerptChunks<'a> {
 481    excerpt_id: ExcerptId,
 482    content_chunks: BufferChunks<'a>,
 483    footer_height: usize,
 484}
 485
 486#[derive(Debug)]
 487struct BufferEdit {
 488    range: Range<usize>,
 489    new_text: Arc<str>,
 490    is_insertion: bool,
 491    original_start_column: u32,
 492    excerpt_id: ExcerptId,
 493}
 494
 495#[derive(Clone, Copy, Debug, PartialEq)]
 496enum DiffChangeKind {
 497    BufferEdited,
 498    DiffUpdated { base_changed: bool },
 499    ExpandOrCollapseHunks { expand: bool },
 500}
 501
 502#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 503pub enum ExpandExcerptDirection {
 504    Up,
 505    Down,
 506    UpAndDown,
 507}
 508
 509impl ExpandExcerptDirection {
 510    pub fn should_expand_up(&self) -> bool {
 511        match self {
 512            ExpandExcerptDirection::Up => true,
 513            ExpandExcerptDirection::Down => false,
 514            ExpandExcerptDirection::UpAndDown => true,
 515        }
 516    }
 517
 518    pub fn should_expand_down(&self) -> bool {
 519        match self {
 520            ExpandExcerptDirection::Up => false,
 521            ExpandExcerptDirection::Down => true,
 522            ExpandExcerptDirection::UpAndDown => true,
 523        }
 524    }
 525}
 526
 527#[derive(Clone, Debug, PartialEq)]
 528pub struct IndentGuide {
 529    pub buffer_id: BufferId,
 530    pub start_row: MultiBufferRow,
 531    pub end_row: MultiBufferRow,
 532    pub depth: u32,
 533    pub tab_size: u32,
 534    pub settings: IndentGuideSettings,
 535}
 536
 537impl IndentGuide {
 538    pub fn indent_level(&self) -> u32 {
 539        self.depth * self.tab_size
 540    }
 541}
 542
 543impl MultiBuffer {
 544    pub fn new(capability: Capability) -> Self {
 545        Self {
 546            snapshot: RefCell::new(MultiBufferSnapshot {
 547                show_headers: true,
 548                ..MultiBufferSnapshot::default()
 549            }),
 550            buffers: RefCell::default(),
 551            diffs: HashMap::default(),
 552            all_diff_hunks_expanded: false,
 553            subscriptions: Topic::default(),
 554            singleton: false,
 555            capability,
 556            title: None,
 557            buffers_by_path: Default::default(),
 558            history: History {
 559                next_transaction_id: clock::Lamport::default(),
 560                undo_stack: Vec::new(),
 561                redo_stack: Vec::new(),
 562                transaction_depth: 0,
 563                group_interval: Duration::from_millis(300),
 564            },
 565        }
 566    }
 567
 568    pub fn without_headers(capability: Capability) -> Self {
 569        Self {
 570            snapshot: Default::default(),
 571            buffers: Default::default(),
 572            buffers_by_path: Default::default(),
 573            diffs: HashMap::default(),
 574            all_diff_hunks_expanded: false,
 575            subscriptions: Default::default(),
 576            singleton: false,
 577            capability,
 578            history: History {
 579                next_transaction_id: Default::default(),
 580                undo_stack: Default::default(),
 581                redo_stack: Default::default(),
 582                transaction_depth: 0,
 583                group_interval: Duration::from_millis(300),
 584            },
 585            title: Default::default(),
 586        }
 587    }
 588
 589    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 590        let mut buffers = HashMap::default();
 591        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 592            buffers.insert(
 593                *buffer_id,
 594                BufferState {
 595                    buffer: buffer_state.buffer.clone(),
 596                    last_version: buffer_state.last_version.clone(),
 597                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 598                    excerpts: buffer_state.excerpts.clone(),
 599                    _subscriptions: [
 600                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 601                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 602                    ],
 603                },
 604            );
 605        }
 606        let mut diff_bases = HashMap::default();
 607        for (buffer_id, diff) in self.diffs.iter() {
 608            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 609        }
 610        Self {
 611            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 612            buffers: RefCell::new(buffers),
 613            buffers_by_path: Default::default(),
 614            diffs: diff_bases,
 615            all_diff_hunks_expanded: self.all_diff_hunks_expanded,
 616            subscriptions: Default::default(),
 617            singleton: self.singleton,
 618            capability: self.capability,
 619            history: self.history.clone(),
 620            title: self.title.clone(),
 621        }
 622    }
 623
 624    pub fn with_title(mut self, title: String) -> Self {
 625        self.title = Some(title);
 626        self
 627    }
 628
 629    pub fn read_only(&self) -> bool {
 630        self.capability == Capability::ReadOnly
 631    }
 632
 633    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 634        let mut this = Self::new(buffer.read(cx).capability());
 635        this.singleton = true;
 636        this.push_excerpts(
 637            buffer,
 638            [ExcerptRange {
 639                context: text::Anchor::MIN..text::Anchor::MAX,
 640                primary: None,
 641            }],
 642            cx,
 643        );
 644        this.snapshot.borrow_mut().singleton = true;
 645        this
 646    }
 647
 648    /// Returns an up-to-date snapshot of the MultiBuffer.
 649    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 650        self.sync(cx);
 651        self.snapshot.borrow().clone()
 652    }
 653
 654    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 655        self.sync(cx);
 656        self.snapshot.borrow()
 657    }
 658
 659    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 660        if self.singleton {
 661            return Some(
 662                self.buffers
 663                    .borrow()
 664                    .values()
 665                    .next()
 666                    .unwrap()
 667                    .buffer
 668                    .clone(),
 669            );
 670        } else {
 671            None
 672        }
 673    }
 674
 675    pub fn is_singleton(&self) -> bool {
 676        self.singleton
 677    }
 678
 679    pub fn subscribe(&mut self) -> Subscription {
 680        self.subscriptions.subscribe()
 681    }
 682
 683    pub fn is_dirty(&self, cx: &App) -> bool {
 684        self.read(cx).is_dirty()
 685    }
 686
 687    pub fn has_deleted_file(&self, cx: &App) -> bool {
 688        self.read(cx).has_deleted_file()
 689    }
 690
 691    pub fn has_conflict(&self, cx: &App) -> bool {
 692        self.read(cx).has_conflict()
 693    }
 694
 695    // The `is_empty` signature doesn't match what clippy expects
 696    #[allow(clippy::len_without_is_empty)]
 697    pub fn len(&self, cx: &App) -> usize {
 698        self.read(cx).len()
 699    }
 700
 701    pub fn is_empty(&self) -> bool {
 702        self.buffers.borrow().is_empty()
 703    }
 704
 705    pub fn symbols_containing<T: ToOffset>(
 706        &self,
 707        offset: T,
 708        theme: Option<&SyntaxTheme>,
 709        cx: &App,
 710    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 711        self.read(cx).symbols_containing(offset, theme)
 712    }
 713
 714    pub fn edit<I, S, T>(
 715        &self,
 716        edits: I,
 717        autoindent_mode: Option<AutoindentMode>,
 718        cx: &mut Context<Self>,
 719    ) where
 720        I: IntoIterator<Item = (Range<S>, T)>,
 721        S: ToOffset,
 722        T: Into<Arc<str>>,
 723    {
 724        let snapshot = self.read(cx);
 725        let edits = edits
 726            .into_iter()
 727            .map(|(range, new_text)| {
 728                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 729                if range.start > range.end {
 730                    mem::swap(&mut range.start, &mut range.end);
 731                }
 732                (range, new_text.into())
 733            })
 734            .collect::<Vec<_>>();
 735
 736        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 737
 738        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 739        fn edit_internal(
 740            this: &MultiBuffer,
 741            snapshot: Ref<MultiBufferSnapshot>,
 742            edits: Vec<(Range<usize>, Arc<str>)>,
 743            mut autoindent_mode: Option<AutoindentMode>,
 744            cx: &mut Context<MultiBuffer>,
 745        ) {
 746            if this.read_only() || this.buffers.borrow().is_empty() {
 747                return;
 748            }
 749
 750            let original_start_columns = match &mut autoindent_mode {
 751                Some(AutoindentMode::Block {
 752                    original_start_columns,
 753                }) => mem::take(original_start_columns),
 754                _ => Default::default(),
 755            };
 756
 757            let (buffer_edits, edited_excerpt_ids) =
 758                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_start_columns);
 759            drop(snapshot);
 760
 761            for (buffer_id, mut edits) in buffer_edits {
 762                edits.sort_by_key(|edit| edit.range.start);
 763                this.buffers.borrow()[&buffer_id]
 764                    .buffer
 765                    .update(cx, |buffer, cx| {
 766                        let mut edits = edits.into_iter().peekable();
 767                        let mut insertions = Vec::new();
 768                        let mut original_indent_columns = Vec::new();
 769                        let mut deletions = Vec::new();
 770                        let empty_str: Arc<str> = Arc::default();
 771                        while let Some(BufferEdit {
 772                            mut range,
 773                            mut new_text,
 774                            mut is_insertion,
 775                            original_start_column: original_indent_column,
 776                            excerpt_id,
 777                        }) = edits.next()
 778                        {
 779                            while let Some(BufferEdit {
 780                                range: next_range,
 781                                is_insertion: next_is_insertion,
 782                                new_text: next_new_text,
 783                                excerpt_id: next_excerpt_id,
 784                                ..
 785                            }) = edits.peek()
 786                            {
 787                                if range.end >= next_range.start {
 788                                    range.end = cmp::max(next_range.end, range.end);
 789                                    is_insertion |= *next_is_insertion;
 790                                    if excerpt_id == *next_excerpt_id {
 791                                        new_text = format!("{new_text}{next_new_text}").into();
 792                                    }
 793                                    edits.next();
 794                                } else {
 795                                    break;
 796                                }
 797                            }
 798
 799                            if is_insertion {
 800                                original_indent_columns.push(original_indent_column);
 801                                insertions.push((
 802                                    buffer.anchor_before(range.start)
 803                                        ..buffer.anchor_before(range.end),
 804                                    new_text.clone(),
 805                                ));
 806                            } else if !range.is_empty() {
 807                                deletions.push((
 808                                    buffer.anchor_before(range.start)
 809                                        ..buffer.anchor_before(range.end),
 810                                    empty_str.clone(),
 811                                ));
 812                            }
 813                        }
 814
 815                        let deletion_autoindent_mode =
 816                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 817                                Some(AutoindentMode::Block {
 818                                    original_start_columns: Default::default(),
 819                                })
 820                            } else {
 821                                autoindent_mode.clone()
 822                            };
 823                        let insertion_autoindent_mode =
 824                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 825                                Some(AutoindentMode::Block {
 826                                    original_start_columns: original_indent_columns,
 827                                })
 828                            } else {
 829                                autoindent_mode.clone()
 830                            };
 831
 832                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 833                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 834                    })
 835            }
 836
 837            cx.emit(Event::ExcerptsEdited {
 838                ids: edited_excerpt_ids,
 839            });
 840        }
 841    }
 842
 843    fn convert_edits_to_buffer_edits(
 844        &self,
 845        edits: Vec<(Range<usize>, Arc<str>)>,
 846        snapshot: &MultiBufferSnapshot,
 847        original_start_columns: &[u32],
 848    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 849        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 850        let mut edited_excerpt_ids = Vec::new();
 851        let mut cursor = snapshot.cursor::<usize>();
 852        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 853            let original_start_column = original_start_columns.get(ix).copied().unwrap_or(0);
 854
 855            cursor.seek(&range.start);
 856            let mut start_region = cursor.region().expect("start offset out of bounds");
 857            if !start_region.is_main_buffer {
 858                cursor.next();
 859                if let Some(region) = cursor.region() {
 860                    start_region = region;
 861                } else {
 862                    continue;
 863                }
 864            }
 865
 866            if range.end < start_region.range.start {
 867                continue;
 868            }
 869
 870            if range.end > start_region.range.end {
 871                cursor.seek_forward(&range.end);
 872            }
 873            let mut end_region = cursor.region().expect("end offset out of bounds");
 874            if !end_region.is_main_buffer {
 875                cursor.prev();
 876                if let Some(region) = cursor.region() {
 877                    end_region = region;
 878                } else {
 879                    continue;
 880                }
 881            }
 882
 883            if range.start > end_region.range.end {
 884                continue;
 885            }
 886
 887            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 888            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 889            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 890                .min(start_region.buffer_range.end);
 891            let buffer_end =
 892                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 893
 894            if start_region.excerpt.id == end_region.excerpt.id {
 895                if start_region.is_main_buffer {
 896                    edited_excerpt_ids.push(start_region.excerpt.id);
 897                    buffer_edits
 898                        .entry(start_region.buffer.remote_id())
 899                        .or_default()
 900                        .push(BufferEdit {
 901                            range: buffer_start..buffer_end,
 902                            new_text,
 903                            is_insertion: true,
 904                            original_start_column,
 905                            excerpt_id: start_region.excerpt.id,
 906                        });
 907                }
 908            } else {
 909                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 910                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 911                if start_region.is_main_buffer {
 912                    edited_excerpt_ids.push(start_region.excerpt.id);
 913                    buffer_edits
 914                        .entry(start_region.buffer.remote_id())
 915                        .or_default()
 916                        .push(BufferEdit {
 917                            range: start_excerpt_range,
 918                            new_text: new_text.clone(),
 919                            is_insertion: true,
 920                            original_start_column,
 921                            excerpt_id: start_region.excerpt.id,
 922                        });
 923                }
 924                if end_region.is_main_buffer {
 925                    edited_excerpt_ids.push(end_region.excerpt.id);
 926                    buffer_edits
 927                        .entry(end_region.buffer.remote_id())
 928                        .or_default()
 929                        .push(BufferEdit {
 930                            range: end_excerpt_range,
 931                            new_text: new_text.clone(),
 932                            is_insertion: false,
 933                            original_start_column,
 934                            excerpt_id: end_region.excerpt.id,
 935                        });
 936                }
 937
 938                cursor.seek(&range.start);
 939                cursor.next_excerpt();
 940                while let Some(region) = cursor.region() {
 941                    if region.excerpt.id == end_region.excerpt.id {
 942                        break;
 943                    }
 944                    if region.is_main_buffer {
 945                        edited_excerpt_ids.push(region.excerpt.id);
 946                        buffer_edits
 947                            .entry(region.buffer.remote_id())
 948                            .or_default()
 949                            .push(BufferEdit {
 950                                range: region.buffer_range,
 951                                new_text: new_text.clone(),
 952                                is_insertion: false,
 953                                original_start_column,
 954                                excerpt_id: region.excerpt.id,
 955                            });
 956                    }
 957                    cursor.next_excerpt();
 958                }
 959            }
 960        }
 961        (buffer_edits, edited_excerpt_ids)
 962    }
 963
 964    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 965    where
 966        I: IntoIterator<Item = Range<S>>,
 967        S: ToOffset,
 968    {
 969        let snapshot = self.read(cx);
 970        let empty = Arc::<str>::from("");
 971        let edits = ranges
 972            .into_iter()
 973            .map(|range| {
 974                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 975                if range.start > range.end {
 976                    mem::swap(&mut range.start, &mut range.end);
 977                }
 978                (range, empty.clone())
 979            })
 980            .collect::<Vec<_>>();
 981
 982        return autoindent_ranges_internal(self, snapshot, edits, cx);
 983
 984        fn autoindent_ranges_internal(
 985            this: &MultiBuffer,
 986            snapshot: Ref<MultiBufferSnapshot>,
 987            edits: Vec<(Range<usize>, Arc<str>)>,
 988            cx: &mut Context<MultiBuffer>,
 989        ) {
 990            if this.read_only() || this.buffers.borrow().is_empty() {
 991                return;
 992            }
 993
 994            let (buffer_edits, edited_excerpt_ids) =
 995                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
 996            drop(snapshot);
 997
 998            for (buffer_id, mut edits) in buffer_edits {
 999                edits.sort_unstable_by_key(|edit| edit.range.start);
1000
1001                let mut ranges: Vec<Range<usize>> = Vec::new();
1002                for edit in edits {
1003                    if let Some(last_range) = ranges.last_mut() {
1004                        if edit.range.start <= last_range.end {
1005                            last_range.end = last_range.end.max(edit.range.end);
1006                            continue;
1007                        }
1008                    }
1009                    ranges.push(edit.range);
1010                }
1011
1012                this.buffers.borrow()[&buffer_id]
1013                    .buffer
1014                    .update(cx, |buffer, cx| {
1015                        buffer.autoindent_ranges(ranges, cx);
1016                    })
1017            }
1018
1019            cx.emit(Event::ExcerptsEdited {
1020                ids: edited_excerpt_ids,
1021            });
1022        }
1023    }
1024
1025    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1026    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1027    // Panics if the given position is invalid.
1028    pub fn insert_empty_line(
1029        &mut self,
1030        position: impl ToPoint,
1031        space_above: bool,
1032        space_below: bool,
1033        cx: &mut Context<Self>,
1034    ) -> Point {
1035        let multibuffer_point = position.to_point(&self.read(cx));
1036        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1037        self.start_transaction(cx);
1038        let empty_line_start = buffer.update(cx, |buffer, cx| {
1039            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1040        });
1041        self.end_transaction(cx);
1042        multibuffer_point + (empty_line_start - buffer_point)
1043    }
1044
1045    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1046        self.start_transaction_at(Instant::now(), cx)
1047    }
1048
1049    pub fn start_transaction_at(
1050        &mut self,
1051        now: Instant,
1052        cx: &mut Context<Self>,
1053    ) -> Option<TransactionId> {
1054        if let Some(buffer) = self.as_singleton() {
1055            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1056        }
1057
1058        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1059            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1060        }
1061        self.history.start_transaction(now)
1062    }
1063
1064    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1065        self.end_transaction_at(Instant::now(), cx)
1066    }
1067
1068    pub fn end_transaction_at(
1069        &mut self,
1070        now: Instant,
1071        cx: &mut Context<Self>,
1072    ) -> Option<TransactionId> {
1073        if let Some(buffer) = self.as_singleton() {
1074            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1075        }
1076
1077        let mut buffer_transactions = HashMap::default();
1078        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1079            if let Some(transaction_id) =
1080                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1081            {
1082                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1083            }
1084        }
1085
1086        if self.history.end_transaction(now, buffer_transactions) {
1087            let transaction_id = self.history.group().unwrap();
1088            Some(transaction_id)
1089        } else {
1090            None
1091        }
1092    }
1093
1094    pub fn edited_ranges_for_transaction<D>(
1095        &self,
1096        transaction_id: TransactionId,
1097        cx: &App,
1098    ) -> Vec<Range<D>>
1099    where
1100        D: TextDimension + Ord + Sub<D, Output = D>,
1101    {
1102        let Some(transaction) = self.history.transaction(transaction_id) else {
1103            return Vec::new();
1104        };
1105
1106        let mut ranges = Vec::new();
1107        let snapshot = self.read(cx);
1108        let buffers = self.buffers.borrow();
1109        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1110
1111        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1112            let Some(buffer_state) = buffers.get(buffer_id) else {
1113                continue;
1114            };
1115
1116            let buffer = buffer_state.buffer.read(cx);
1117            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1118                for excerpt_id in &buffer_state.excerpts {
1119                    cursor.seek(excerpt_id, Bias::Left, &());
1120                    if let Some(excerpt) = cursor.item() {
1121                        if excerpt.locator == *excerpt_id {
1122                            let excerpt_buffer_start =
1123                                excerpt.range.context.start.summary::<D>(buffer);
1124                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1125                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1126                            if excerpt_range.contains(&range.start)
1127                                && excerpt_range.contains(&range.end)
1128                            {
1129                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1130
1131                                let mut start = excerpt_start;
1132                                start.add_assign(&(range.start - excerpt_buffer_start));
1133                                let mut end = excerpt_start;
1134                                end.add_assign(&(range.end - excerpt_buffer_start));
1135
1136                                ranges.push(start..end);
1137                                break;
1138                            }
1139                        }
1140                    }
1141                }
1142            }
1143        }
1144
1145        ranges.sort_by_key(|range| range.start);
1146        ranges
1147    }
1148
1149    pub fn merge_transactions(
1150        &mut self,
1151        transaction: TransactionId,
1152        destination: TransactionId,
1153        cx: &mut Context<Self>,
1154    ) {
1155        if let Some(buffer) = self.as_singleton() {
1156            buffer.update(cx, |buffer, _| {
1157                buffer.merge_transactions(transaction, destination)
1158            });
1159        } else if let Some(transaction) = self.history.forget(transaction) {
1160            if let Some(destination) = self.history.transaction_mut(destination) {
1161                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1162                    if let Some(destination_buffer_transaction_id) =
1163                        destination.buffer_transactions.get(&buffer_id)
1164                    {
1165                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1166                            state.buffer.update(cx, |buffer, _| {
1167                                buffer.merge_transactions(
1168                                    buffer_transaction_id,
1169                                    *destination_buffer_transaction_id,
1170                                )
1171                            });
1172                        }
1173                    } else {
1174                        destination
1175                            .buffer_transactions
1176                            .insert(buffer_id, buffer_transaction_id);
1177                    }
1178                }
1179            }
1180        }
1181    }
1182
1183    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1184        self.history.finalize_last_transaction();
1185        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1186            buffer.update(cx, |buffer, _| {
1187                buffer.finalize_last_transaction();
1188            });
1189        }
1190    }
1191
1192    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1193    where
1194        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1195    {
1196        self.history
1197            .push_transaction(buffer_transactions, Instant::now(), cx);
1198        self.history.finalize_last_transaction();
1199    }
1200
1201    pub fn group_until_transaction(
1202        &mut self,
1203        transaction_id: TransactionId,
1204        cx: &mut Context<Self>,
1205    ) {
1206        if let Some(buffer) = self.as_singleton() {
1207            buffer.update(cx, |buffer, _| {
1208                buffer.group_until_transaction(transaction_id)
1209            });
1210        } else {
1211            self.history.group_until(transaction_id);
1212        }
1213    }
1214
1215    pub fn set_active_selections(
1216        &self,
1217        selections: &[Selection<Anchor>],
1218        line_mode: bool,
1219        cursor_shape: CursorShape,
1220        cx: &mut Context<Self>,
1221    ) {
1222        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1223            Default::default();
1224        let snapshot = self.read(cx);
1225        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1226        for selection in selections {
1227            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1228            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1229
1230            cursor.seek(&Some(start_locator), Bias::Left, &());
1231            while let Some(excerpt) = cursor.item() {
1232                if excerpt.locator > *end_locator {
1233                    break;
1234                }
1235
1236                let mut start = excerpt.range.context.start;
1237                let mut end = excerpt.range.context.end;
1238                if excerpt.id == selection.start.excerpt_id {
1239                    start = selection.start.text_anchor;
1240                }
1241                if excerpt.id == selection.end.excerpt_id {
1242                    end = selection.end.text_anchor;
1243                }
1244                selections_by_buffer
1245                    .entry(excerpt.buffer_id)
1246                    .or_default()
1247                    .push(Selection {
1248                        id: selection.id,
1249                        start,
1250                        end,
1251                        reversed: selection.reversed,
1252                        goal: selection.goal,
1253                    });
1254
1255                cursor.next(&());
1256            }
1257        }
1258
1259        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1260            if !selections_by_buffer.contains_key(buffer_id) {
1261                buffer_state
1262                    .buffer
1263                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1264            }
1265        }
1266
1267        for (buffer_id, mut selections) in selections_by_buffer {
1268            self.buffers.borrow()[&buffer_id]
1269                .buffer
1270                .update(cx, |buffer, cx| {
1271                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1272                    let mut selections = selections.into_iter().peekable();
1273                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1274                        let mut selection = selections.next()?;
1275                        while let Some(next_selection) = selections.peek() {
1276                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1277                                let next_selection = selections.next().unwrap();
1278                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1279                                    selection.end = next_selection.end;
1280                                }
1281                            } else {
1282                                break;
1283                            }
1284                        }
1285                        Some(selection)
1286                    }));
1287                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1288                });
1289        }
1290    }
1291
1292    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1293        for buffer in self.buffers.borrow().values() {
1294            buffer
1295                .buffer
1296                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1297        }
1298    }
1299
1300    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1301        let mut transaction_id = None;
1302        if let Some(buffer) = self.as_singleton() {
1303            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1304        } else {
1305            while let Some(transaction) = self.history.pop_undo() {
1306                let mut undone = false;
1307                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1308                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1309                        undone |= buffer.update(cx, |buffer, cx| {
1310                            let undo_to = *buffer_transaction_id;
1311                            if let Some(entry) = buffer.peek_undo_stack() {
1312                                *buffer_transaction_id = entry.transaction_id();
1313                            }
1314                            buffer.undo_to_transaction(undo_to, cx)
1315                        });
1316                    }
1317                }
1318
1319                if undone {
1320                    transaction_id = Some(transaction.id);
1321                    break;
1322                }
1323            }
1324        }
1325
1326        if let Some(transaction_id) = transaction_id {
1327            cx.emit(Event::TransactionUndone { transaction_id });
1328        }
1329
1330        transaction_id
1331    }
1332
1333    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1334        if let Some(buffer) = self.as_singleton() {
1335            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1336        }
1337
1338        while let Some(transaction) = self.history.pop_redo() {
1339            let mut redone = false;
1340            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1341                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1342                    redone |= buffer.update(cx, |buffer, cx| {
1343                        let redo_to = *buffer_transaction_id;
1344                        if let Some(entry) = buffer.peek_redo_stack() {
1345                            *buffer_transaction_id = entry.transaction_id();
1346                        }
1347                        buffer.redo_to_transaction(redo_to, cx)
1348                    });
1349                }
1350            }
1351
1352            if redone {
1353                return Some(transaction.id);
1354            }
1355        }
1356
1357        None
1358    }
1359
1360    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1361        if let Some(buffer) = self.as_singleton() {
1362            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1363        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1364            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1365                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1366                    buffer.update(cx, |buffer, cx| {
1367                        buffer.undo_transaction(*transaction_id, cx)
1368                    });
1369                }
1370            }
1371        }
1372    }
1373
1374    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1375        if let Some(buffer) = self.as_singleton() {
1376            buffer.update(cx, |buffer, _| {
1377                buffer.forget_transaction(transaction_id);
1378            });
1379        } else if let Some(transaction) = self.history.forget(transaction_id) {
1380            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1381                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1382                    state.buffer.update(cx, |buffer, _| {
1383                        buffer.forget_transaction(buffer_transaction_id);
1384                    });
1385                }
1386            }
1387        }
1388    }
1389
1390    pub fn push_excerpts<O>(
1391        &mut self,
1392        buffer: Entity<Buffer>,
1393        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1394        cx: &mut Context<Self>,
1395    ) -> Vec<ExcerptId>
1396    where
1397        O: text::ToOffset,
1398    {
1399        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1400    }
1401
1402    pub fn push_excerpts_with_context_lines<O>(
1403        &mut self,
1404        buffer: Entity<Buffer>,
1405        ranges: Vec<Range<O>>,
1406        context_line_count: u32,
1407        cx: &mut Context<Self>,
1408    ) -> Vec<Range<Anchor>>
1409    where
1410        O: text::ToPoint + text::ToOffset,
1411    {
1412        let buffer_id = buffer.read(cx).remote_id();
1413        let buffer_snapshot = buffer.read(cx).snapshot();
1414        let (excerpt_ranges, range_counts) =
1415            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1416
1417        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1418
1419        let mut anchor_ranges = Vec::new();
1420        let mut ranges = ranges.into_iter();
1421        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1422            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1423                let start = Anchor {
1424                    buffer_id: Some(buffer_id),
1425                    excerpt_id,
1426                    text_anchor: buffer_snapshot.anchor_after(range.start),
1427                    diff_base_anchor: None,
1428                };
1429                let end = Anchor {
1430                    buffer_id: Some(buffer_id),
1431                    excerpt_id,
1432                    text_anchor: buffer_snapshot.anchor_after(range.end),
1433                    diff_base_anchor: None,
1434                };
1435                start..end
1436            }))
1437        }
1438        anchor_ranges
1439    }
1440
1441    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1442        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1443        let snapshot = self.snapshot(cx);
1444        let excerpt = snapshot.excerpt(*excerpt_id)?;
1445        Some(Anchor::in_buffer(
1446            *excerpt_id,
1447            excerpt.buffer_id,
1448            excerpt.range.context.start,
1449        ))
1450    }
1451
1452    pub fn set_excerpts_for_path(
1453        &mut self,
1454        path: PathKey,
1455        buffer: Entity<Buffer>,
1456        ranges: Vec<Range<Point>>,
1457        context_line_count: u32,
1458        cx: &mut Context<Self>,
1459    ) {
1460        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1461
1462        let mut insert_after = self
1463            .buffers_by_path
1464            .range(..path.clone())
1465            .next_back()
1466            .map(|(_, value)| *value.last().unwrap())
1467            .unwrap_or(ExcerptId::min());
1468        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1469
1470        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1471
1472        let mut new_iter = new.into_iter().peekable();
1473        let mut existing_iter = existing.into_iter().peekable();
1474
1475        let mut new_excerpt_ids = Vec::new();
1476        let mut to_remove = Vec::new();
1477        let mut to_insert = Vec::new();
1478        let snapshot = self.snapshot(cx);
1479
1480        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1481        excerpts_cursor.next(&());
1482
1483        loop {
1484            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1485                (Some(new), Some(existing)) => (new, existing),
1486                (None, None) => break,
1487                (None, Some(_)) => {
1488                    to_remove.push(existing_iter.next().unwrap());
1489                    continue;
1490                }
1491                (Some(_), None) => {
1492                    to_insert.push(new_iter.next().unwrap());
1493                    continue;
1494                }
1495            };
1496            let locator = snapshot.excerpt_locator_for_id(*existing);
1497            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1498            let existing_excerpt = excerpts_cursor.item().unwrap();
1499            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1500                to_remove.push(existing_iter.next().unwrap());
1501                to_insert.push(new_iter.next().unwrap());
1502                continue;
1503            }
1504
1505            let existing_start = existing_excerpt
1506                .range
1507                .context
1508                .start
1509                .to_point(&buffer_snapshot);
1510            let existing_end = existing_excerpt
1511                .range
1512                .context
1513                .end
1514                .to_point(&buffer_snapshot);
1515
1516            if existing_end < new.context.start {
1517                to_remove.push(existing_iter.next().unwrap());
1518                continue;
1519            } else if existing_start > new.context.end {
1520                to_insert.push(new_iter.next().unwrap());
1521                continue;
1522            }
1523
1524            // maybe merge overlapping excerpts?
1525            // it's hard to distinguish between a manually expanded excerpt, and one that
1526            // got smaller because of a missing diff.
1527            if existing_start == new.context.start && existing_end == new.context.end {
1528                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1529                    insert_after,
1530                    buffer.clone(),
1531                    mem::take(&mut to_insert),
1532                    cx,
1533                ));
1534                insert_after = existing_iter.next().unwrap();
1535                new_excerpt_ids.push(insert_after);
1536                new_iter.next();
1537            } else {
1538                to_remove.push(existing_iter.next().unwrap());
1539                to_insert.push(new_iter.next().unwrap());
1540            }
1541        }
1542
1543        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1544            insert_after,
1545            buffer,
1546            to_insert,
1547            cx,
1548        ));
1549        self.remove_excerpts(to_remove, cx);
1550        if new_excerpt_ids.is_empty() {
1551            self.buffers_by_path.remove(&path);
1552        } else {
1553            self.buffers_by_path.insert(path, new_excerpt_ids);
1554        }
1555    }
1556
1557    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1558        self.buffers_by_path.keys().cloned()
1559    }
1560
1561    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1562        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1563            self.remove_excerpts(to_remove, cx)
1564        }
1565    }
1566
1567    pub fn push_multiple_excerpts_with_context_lines(
1568        &self,
1569        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1570        context_line_count: u32,
1571        cx: &mut Context<Self>,
1572    ) -> Task<Vec<Range<Anchor>>> {
1573        use futures::StreamExt;
1574
1575        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1576
1577        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1578
1579        for (buffer, ranges) in buffers_with_ranges {
1580            let (buffer_id, buffer_snapshot) =
1581                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1582
1583            buffer_ids.push(buffer_id);
1584
1585            cx.background_spawn({
1586                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1587
1588                async move {
1589                    let (excerpt_ranges, counts) =
1590                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1591                    excerpt_ranges_tx
1592                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1593                        .await
1594                        .ok();
1595                }
1596            })
1597            .detach()
1598        }
1599
1600        cx.spawn(move |this, mut cx| async move {
1601            let mut results_by_buffer_id = HashMap::default();
1602            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1603                excerpt_ranges_rx.next().await
1604            {
1605                results_by_buffer_id
1606                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1607            }
1608
1609            let mut multi_buffer_ranges = Vec::default();
1610            'outer: for buffer_id in buffer_ids {
1611                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1612                    results_by_buffer_id.remove(&buffer_id)
1613                else {
1614                    continue;
1615                };
1616
1617                let mut ranges = ranges.into_iter();
1618                let mut range_counts = range_counts.into_iter();
1619                for excerpt_ranges in excerpt_ranges.chunks(100) {
1620                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1621                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1622                    }) {
1623                        Ok(excerpt_ids) => excerpt_ids,
1624                        Err(_) => continue 'outer,
1625                    };
1626
1627                    for (excerpt_id, range_count) in
1628                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1629                    {
1630                        for range in ranges.by_ref().take(range_count) {
1631                            let start = Anchor {
1632                                buffer_id: Some(buffer_id),
1633                                excerpt_id,
1634                                text_anchor: range.start,
1635                                diff_base_anchor: None,
1636                            };
1637                            let end = Anchor {
1638                                buffer_id: Some(buffer_id),
1639                                excerpt_id,
1640                                text_anchor: range.end,
1641                                diff_base_anchor: None,
1642                            };
1643                            multi_buffer_ranges.push(start..end);
1644                        }
1645                    }
1646                }
1647            }
1648
1649            multi_buffer_ranges
1650        })
1651    }
1652
1653    pub fn insert_excerpts_after<O>(
1654        &mut self,
1655        prev_excerpt_id: ExcerptId,
1656        buffer: Entity<Buffer>,
1657        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1658        cx: &mut Context<Self>,
1659    ) -> Vec<ExcerptId>
1660    where
1661        O: text::ToOffset,
1662    {
1663        let mut ids = Vec::new();
1664        let mut next_excerpt_id =
1665            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1666                last_entry.id.0 + 1
1667            } else {
1668                1
1669            };
1670        self.insert_excerpts_with_ids_after(
1671            prev_excerpt_id,
1672            buffer,
1673            ranges.into_iter().map(|range| {
1674                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1675                ids.push(id);
1676                (id, range)
1677            }),
1678            cx,
1679        );
1680        ids
1681    }
1682
1683    pub fn insert_excerpts_with_ids_after<O>(
1684        &mut self,
1685        prev_excerpt_id: ExcerptId,
1686        buffer: Entity<Buffer>,
1687        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1688        cx: &mut Context<Self>,
1689    ) where
1690        O: text::ToOffset,
1691    {
1692        assert_eq!(self.history.transaction_depth, 0);
1693        let mut ranges = ranges.into_iter().peekable();
1694        if ranges.peek().is_none() {
1695            return Default::default();
1696        }
1697
1698        self.sync(cx);
1699
1700        let buffer_id = buffer.read(cx).remote_id();
1701        let buffer_snapshot = buffer.read(cx).snapshot();
1702
1703        let mut buffers = self.buffers.borrow_mut();
1704        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1705            last_version: buffer_snapshot.version().clone(),
1706            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1707            excerpts: Default::default(),
1708            _subscriptions: [
1709                cx.observe(&buffer, |_, _, cx| cx.notify()),
1710                cx.subscribe(&buffer, Self::on_buffer_event),
1711            ],
1712            buffer: buffer.clone(),
1713        });
1714
1715        let mut snapshot = self.snapshot.borrow_mut();
1716
1717        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1718        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1719        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1720        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1721        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1722
1723        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1724        new_excerpts.update_last(
1725            |excerpt| {
1726                excerpt.has_trailing_newline = true;
1727            },
1728            &(),
1729        );
1730
1731        let next_locator = if let Some(excerpt) = cursor.item() {
1732            excerpt.locator.clone()
1733        } else {
1734            Locator::max()
1735        };
1736
1737        let mut excerpts = Vec::new();
1738        while let Some((id, range)) = ranges.next() {
1739            let locator = Locator::between(&prev_locator, &next_locator);
1740            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1741                buffer_state.excerpts.insert(ix, locator.clone());
1742            }
1743            let range = ExcerptRange {
1744                context: buffer_snapshot.anchor_before(&range.context.start)
1745                    ..buffer_snapshot.anchor_after(&range.context.end),
1746                primary: range.primary.map(|primary| {
1747                    buffer_snapshot.anchor_before(&primary.start)
1748                        ..buffer_snapshot.anchor_after(&primary.end)
1749                }),
1750            };
1751            excerpts.push((id, range.clone()));
1752            let excerpt = Excerpt::new(
1753                id,
1754                locator.clone(),
1755                buffer_id,
1756                buffer_snapshot.clone(),
1757                range,
1758                ranges.peek().is_some() || cursor.item().is_some(),
1759            );
1760            new_excerpts.push(excerpt, &());
1761            prev_locator = locator.clone();
1762
1763            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1764                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1765            }
1766            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1767        }
1768
1769        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1770
1771        let suffix = cursor.suffix(&());
1772        let changed_trailing_excerpt = suffix.is_empty();
1773        new_excerpts.append(suffix, &());
1774        drop(cursor);
1775        snapshot.excerpts = new_excerpts;
1776        snapshot.excerpt_ids = new_excerpt_ids;
1777        if changed_trailing_excerpt {
1778            snapshot.trailing_excerpt_update_count += 1;
1779        }
1780
1781        self.sync_diff_transforms(
1782            &mut snapshot,
1783            vec![Edit {
1784                old: edit_start..edit_start,
1785                new: edit_start..edit_end,
1786            }],
1787            DiffChangeKind::BufferEdited,
1788        );
1789        cx.emit(Event::Edited {
1790            singleton_buffer_edited: false,
1791            edited_buffer: None,
1792        });
1793        cx.emit(Event::ExcerptsAdded {
1794            buffer,
1795            predecessor: prev_excerpt_id,
1796            excerpts,
1797        });
1798        cx.notify();
1799    }
1800
1801    pub fn clear(&mut self, cx: &mut Context<Self>) {
1802        self.sync(cx);
1803        let ids = self.excerpt_ids();
1804        self.buffers.borrow_mut().clear();
1805        let mut snapshot = self.snapshot.borrow_mut();
1806        let start = ExcerptOffset::new(0);
1807        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1808        snapshot.excerpts = Default::default();
1809        snapshot.trailing_excerpt_update_count += 1;
1810        snapshot.is_dirty = false;
1811        snapshot.has_deleted_file = false;
1812        snapshot.has_conflict = false;
1813
1814        self.sync_diff_transforms(
1815            &mut snapshot,
1816            vec![Edit {
1817                old: start..prev_len,
1818                new: start..start,
1819            }],
1820            DiffChangeKind::BufferEdited,
1821        );
1822        cx.emit(Event::Edited {
1823            singleton_buffer_edited: false,
1824            edited_buffer: None,
1825        });
1826        cx.emit(Event::ExcerptsRemoved { ids });
1827        cx.notify();
1828    }
1829
1830    pub fn excerpts_for_buffer(
1831        &self,
1832        buffer_id: BufferId,
1833        cx: &App,
1834    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1835        let mut excerpts = Vec::new();
1836        let snapshot = self.read(cx);
1837        let buffers = self.buffers.borrow();
1838        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1839        for locator in buffers
1840            .get(&buffer_id)
1841            .map(|state| &state.excerpts)
1842            .into_iter()
1843            .flatten()
1844        {
1845            cursor.seek_forward(&Some(locator), Bias::Left, &());
1846            if let Some(excerpt) = cursor.item() {
1847                if excerpt.locator == *locator {
1848                    excerpts.push((excerpt.id, excerpt.range.clone()));
1849                }
1850            }
1851        }
1852
1853        excerpts
1854    }
1855
1856    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1857        let snapshot = self.read(cx);
1858        let buffers = self.buffers.borrow();
1859        let mut excerpts = snapshot
1860            .excerpts
1861            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1862        let mut diff_transforms = snapshot
1863            .diff_transforms
1864            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1865        diff_transforms.next(&());
1866        let locators = buffers
1867            .get(&buffer_id)
1868            .into_iter()
1869            .flat_map(|state| &state.excerpts);
1870        let mut result = Vec::new();
1871        for locator in locators {
1872            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1873            if let Some(excerpt) = excerpts.item() {
1874                if excerpt.locator == *locator {
1875                    let excerpt_start = excerpts.start().1.clone();
1876                    let excerpt_end =
1877                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1878
1879                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1880                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1881                    let start = diff_transforms.start().1 .0 + overshoot;
1882
1883                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1884                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1885                    let end = diff_transforms.start().1 .0 + overshoot;
1886
1887                    result.push(start..end)
1888                }
1889            }
1890        }
1891        result
1892    }
1893
1894    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1895        self.snapshot
1896            .borrow()
1897            .excerpts
1898            .iter()
1899            .map(|entry| entry.buffer_id)
1900            .collect()
1901    }
1902
1903    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1904        self.snapshot
1905            .borrow()
1906            .excerpts
1907            .iter()
1908            .map(|entry| entry.id)
1909            .collect()
1910    }
1911
1912    pub fn excerpt_containing(
1913        &self,
1914        position: impl ToOffset,
1915        cx: &App,
1916    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1917        let snapshot = self.read(cx);
1918        let offset = position.to_offset(&snapshot);
1919
1920        let mut cursor = snapshot.cursor::<usize>();
1921        cursor.seek(&offset);
1922        cursor
1923            .excerpt()
1924            .or_else(|| snapshot.excerpts.last())
1925            .map(|excerpt| {
1926                (
1927                    excerpt.id,
1928                    self.buffers
1929                        .borrow()
1930                        .get(&excerpt.buffer_id)
1931                        .unwrap()
1932                        .buffer
1933                        .clone(),
1934                    excerpt.range.context.clone(),
1935                )
1936            })
1937    }
1938
1939    // If point is at the end of the buffer, the last excerpt is returned
1940    pub fn point_to_buffer_offset<T: ToOffset>(
1941        &self,
1942        point: T,
1943        cx: &App,
1944    ) -> Option<(Entity<Buffer>, usize)> {
1945        let snapshot = self.read(cx);
1946        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1947        Some((
1948            self.buffers
1949                .borrow()
1950                .get(&buffer.remote_id())?
1951                .buffer
1952                .clone(),
1953            offset,
1954        ))
1955    }
1956
1957    // If point is at the end of the buffer, the last excerpt is returned
1958    pub fn point_to_buffer_point<T: ToPoint>(
1959        &self,
1960        point: T,
1961        cx: &App,
1962    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1963        let snapshot = self.read(cx);
1964        let point = point.to_point(&snapshot);
1965        let mut cursor = snapshot.cursor::<Point>();
1966        cursor.seek(&point);
1967
1968        cursor.region().and_then(|region| {
1969            if !region.is_main_buffer {
1970                return None;
1971            }
1972
1973            let overshoot = point - region.range.start;
1974            let buffer_point = region.buffer_range.start + overshoot;
1975            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
1976                .buffer
1977                .clone();
1978            Some((buffer, buffer_point, region.excerpt.id))
1979        })
1980    }
1981
1982    pub fn buffer_point_to_anchor(
1983        &self,
1984        buffer: &Entity<Buffer>,
1985        point: Point,
1986        cx: &App,
1987    ) -> Option<Anchor> {
1988        let mut found = None;
1989        let snapshot = buffer.read(cx).snapshot();
1990        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1991            let start = range.context.start.to_point(&snapshot);
1992            let end = range.context.end.to_point(&snapshot);
1993            if start <= point && point < end {
1994                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1995                break;
1996            }
1997            if point < start {
1998                found = Some((start, excerpt_id));
1999            }
2000            if point > end {
2001                found = Some((end, excerpt_id));
2002            }
2003        }
2004
2005        found.map(|(point, excerpt_id)| {
2006            let text_anchor = snapshot.anchor_after(point);
2007            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2008        })
2009    }
2010
2011    pub fn remove_excerpts(
2012        &mut self,
2013        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2014        cx: &mut Context<Self>,
2015    ) {
2016        self.sync(cx);
2017        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2018        if ids.is_empty() {
2019            return;
2020        }
2021
2022        let mut buffers = self.buffers.borrow_mut();
2023        let mut snapshot = self.snapshot.borrow_mut();
2024        let mut new_excerpts = SumTree::default();
2025        let mut cursor = snapshot
2026            .excerpts
2027            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2028        let mut edits = Vec::new();
2029        let mut excerpt_ids = ids.iter().copied().peekable();
2030
2031        while let Some(excerpt_id) = excerpt_ids.next() {
2032            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2033            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2034            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2035
2036            if let Some(mut excerpt) = cursor.item() {
2037                if excerpt.id != excerpt_id {
2038                    continue;
2039                }
2040                let mut old_start = cursor.start().1;
2041
2042                // Skip over the removed excerpt.
2043                'remove_excerpts: loop {
2044                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2045                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2046                        if buffer_state.excerpts.is_empty() {
2047                            buffers.remove(&excerpt.buffer_id);
2048                        }
2049                    }
2050                    cursor.next(&());
2051
2052                    // Skip over any subsequent excerpts that are also removed.
2053                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2054                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2055                        if let Some(next_excerpt) = cursor.item() {
2056                            if next_excerpt.locator == *next_locator {
2057                                excerpt_ids.next();
2058                                excerpt = next_excerpt;
2059                                continue 'remove_excerpts;
2060                            }
2061                        }
2062                    }
2063
2064                    break;
2065                }
2066
2067                // When removing the last excerpt, remove the trailing newline from
2068                // the previous excerpt.
2069                if cursor.item().is_none() && old_start.value > 0 {
2070                    old_start.value -= 1;
2071                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2072                }
2073
2074                // Push an edit for the removal of this run of excerpts.
2075                let old_end = cursor.start().1;
2076                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2077                edits.push(Edit {
2078                    old: old_start..old_end,
2079                    new: new_start..new_start,
2080                });
2081            }
2082        }
2083        let suffix = cursor.suffix(&());
2084        let changed_trailing_excerpt = suffix.is_empty();
2085        new_excerpts.append(suffix, &());
2086        drop(cursor);
2087        snapshot.excerpts = new_excerpts;
2088
2089        if changed_trailing_excerpt {
2090            snapshot.trailing_excerpt_update_count += 1;
2091        }
2092
2093        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2094        cx.emit(Event::Edited {
2095            singleton_buffer_edited: false,
2096            edited_buffer: None,
2097        });
2098        cx.emit(Event::ExcerptsRemoved { ids });
2099        cx.notify();
2100    }
2101
2102    pub fn wait_for_anchors<'a>(
2103        &self,
2104        anchors: impl 'a + Iterator<Item = Anchor>,
2105        cx: &mut Context<Self>,
2106    ) -> impl 'static + Future<Output = Result<()>> {
2107        let borrow = self.buffers.borrow();
2108        let mut error = None;
2109        let mut futures = Vec::new();
2110        for anchor in anchors {
2111            if let Some(buffer_id) = anchor.buffer_id {
2112                if let Some(buffer) = borrow.get(&buffer_id) {
2113                    buffer.buffer.update(cx, |buffer, _| {
2114                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2115                    });
2116                } else {
2117                    error = Some(anyhow!(
2118                        "buffer {buffer_id} is not part of this multi-buffer"
2119                    ));
2120                    break;
2121                }
2122            }
2123        }
2124        async move {
2125            if let Some(error) = error {
2126                Err(error)?;
2127            }
2128            for future in futures {
2129                future.await?;
2130            }
2131            Ok(())
2132        }
2133    }
2134
2135    pub fn text_anchor_for_position<T: ToOffset>(
2136        &self,
2137        position: T,
2138        cx: &App,
2139    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2140        let snapshot = self.read(cx);
2141        let anchor = snapshot.anchor_before(position);
2142        let buffer = self
2143            .buffers
2144            .borrow()
2145            .get(&anchor.buffer_id?)?
2146            .buffer
2147            .clone();
2148        Some((buffer, anchor.text_anchor))
2149    }
2150
2151    fn on_buffer_event(
2152        &mut self,
2153        buffer: Entity<Buffer>,
2154        event: &language::BufferEvent,
2155        cx: &mut Context<Self>,
2156    ) {
2157        cx.emit(match event {
2158            language::BufferEvent::Edited => Event::Edited {
2159                singleton_buffer_edited: true,
2160                edited_buffer: Some(buffer.clone()),
2161            },
2162            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2163            language::BufferEvent::Saved => Event::Saved,
2164            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2165            language::BufferEvent::Reloaded => Event::Reloaded,
2166            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2167            language::BufferEvent::LanguageChanged => {
2168                Event::LanguageChanged(buffer.read(cx).remote_id())
2169            }
2170            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2171            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2172            language::BufferEvent::Closed => Event::Closed,
2173            language::BufferEvent::Discarded => Event::Discarded,
2174            language::BufferEvent::CapabilityChanged => {
2175                self.capability = buffer.read(cx).capability();
2176                Event::CapabilityChanged
2177            }
2178            language::BufferEvent::Operation { .. } => return,
2179        });
2180    }
2181
2182    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2183        self.sync(cx);
2184        let mut snapshot = self.snapshot.borrow_mut();
2185        let diff = diff.read(cx);
2186        let buffer_id = diff.buffer_id;
2187        let diff = diff.snapshot(cx);
2188        snapshot.diffs.insert(buffer_id, diff);
2189    }
2190
2191    fn buffer_diff_changed(
2192        &mut self,
2193        diff: Entity<BufferDiff>,
2194        range: Range<text::Anchor>,
2195        cx: &mut Context<Self>,
2196    ) {
2197        self.sync(cx);
2198
2199        let diff = diff.read(cx);
2200        let buffer_id = diff.buffer_id;
2201        let buffers = self.buffers.borrow();
2202        let Some(buffer_state) = buffers.get(&buffer_id) else {
2203            return;
2204        };
2205
2206        let buffer = buffer_state.buffer.read(cx);
2207        let diff_change_range = range.to_offset(buffer);
2208
2209        let mut new_diff = diff.snapshot(cx);
2210        if new_diff.base_text().is_none() && self.all_diff_hunks_expanded {
2211            let secondary_diff_insertion = new_diff
2212                .secondary_diff()
2213                .map_or(true, |secondary_diff| secondary_diff.base_text().is_none());
2214            new_diff = BufferDiff::build_with_single_insertion(
2215                secondary_diff_insertion,
2216                buffer.snapshot(),
2217                cx,
2218            );
2219        }
2220
2221        let mut snapshot = self.snapshot.borrow_mut();
2222        let base_text_changed = snapshot
2223            .diffs
2224            .get(&buffer_id)
2225            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2226
2227        snapshot.diffs.insert(buffer_id, new_diff);
2228
2229        let mut excerpt_edits = Vec::new();
2230        for locator in &buffer_state.excerpts {
2231            let mut cursor = snapshot
2232                .excerpts
2233                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2234            cursor.seek_forward(&Some(locator), Bias::Left, &());
2235            if let Some(excerpt) = cursor.item() {
2236                if excerpt.locator == *locator {
2237                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2238                    if diff_change_range.end < excerpt_buffer_range.start
2239                        || diff_change_range.start > excerpt_buffer_range.end
2240                    {
2241                        continue;
2242                    }
2243                    let excerpt_start = cursor.start().1;
2244                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2245                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2246                        diff_change_range
2247                            .start
2248                            .saturating_sub(excerpt_buffer_range.start),
2249                    );
2250                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2251                        diff_change_range
2252                            .end
2253                            .saturating_sub(excerpt_buffer_range.start),
2254                    );
2255                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2256                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2257                    excerpt_edits.push(Edit {
2258                        old: edit_start..edit_end,
2259                        new: edit_start..edit_end,
2260                    });
2261                }
2262            }
2263        }
2264
2265        self.sync_diff_transforms(
2266            &mut snapshot,
2267            excerpt_edits,
2268            DiffChangeKind::DiffUpdated {
2269                base_changed: base_text_changed,
2270            },
2271        );
2272        cx.emit(Event::Edited {
2273            singleton_buffer_edited: false,
2274            edited_buffer: None,
2275        });
2276    }
2277
2278    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2279        self.buffers
2280            .borrow()
2281            .values()
2282            .map(|state| state.buffer.clone())
2283            .collect()
2284    }
2285
2286    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2287        self.buffers
2288            .borrow()
2289            .get(&buffer_id)
2290            .map(|state| state.buffer.clone())
2291    }
2292
2293    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2294        self.point_to_buffer_offset(point, cx)
2295            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2296    }
2297
2298    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2299        let mut language = None;
2300        let mut file = None;
2301        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2302            let buffer = buffer.read(cx);
2303            language = buffer.language_at(offset);
2304            file = buffer.file();
2305        }
2306        language_settings(language.map(|l| l.name()), file, cx)
2307    }
2308
2309    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2310        self.buffers
2311            .borrow()
2312            .values()
2313            .for_each(|state| f(&state.buffer))
2314    }
2315
2316    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2317        if let Some(title) = self.title.as_ref() {
2318            return title.into();
2319        }
2320
2321        if let Some(buffer) = self.as_singleton() {
2322            if let Some(file) = buffer.read(cx).file() {
2323                return file.file_name(cx).to_string_lossy();
2324            }
2325        }
2326
2327        "untitled".into()
2328    }
2329
2330    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2331        self.title = Some(title);
2332        cx.notify();
2333    }
2334
2335    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2336    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2337        for buffer_state in self.buffers.borrow().values() {
2338            buffer_state
2339                .buffer
2340                .update(cx, |buffer, _cx| buffer.refresh_preview());
2341        }
2342    }
2343
2344    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2345    pub fn preserve_preview(&self, cx: &App) -> bool {
2346        self.buffers
2347            .borrow()
2348            .values()
2349            .all(|state| state.buffer.read(cx).preserve_preview())
2350    }
2351
2352    #[cfg(any(test, feature = "test-support"))]
2353    pub fn is_parsing(&self, cx: &App) -> bool {
2354        self.as_singleton().unwrap().read(cx).is_parsing()
2355    }
2356
2357    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2358        let buffer_id = diff.read(cx).buffer_id;
2359        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2360        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2361    }
2362
2363    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2364        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2365    }
2366
2367    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2368        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2369    }
2370
2371    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2372        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2373    }
2374
2375    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2376        self.all_diff_hunks_expanded = true;
2377        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2378    }
2379
2380    pub fn all_diff_hunks_expanded(&self) -> bool {
2381        self.all_diff_hunks_expanded
2382    }
2383
2384    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2385        self.read(cx)
2386            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2387            .nth(1)
2388            .is_some()
2389    }
2390
2391    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2392        let snapshot = self.read(cx);
2393        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2394        let offset_range = range.to_offset(&snapshot);
2395        cursor.seek(&offset_range.start, Bias::Right, &());
2396        while let Some(item) = cursor.item() {
2397            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2398                break;
2399            }
2400            if item.hunk_info().is_some() {
2401                return true;
2402            }
2403            cursor.next(&());
2404        }
2405        false
2406    }
2407
2408    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2409        let snapshot = self.read(cx);
2410        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2411        for range in ranges {
2412            let range = range.to_point(&snapshot);
2413            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2414            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2415            let start = start.saturating_sub(1);
2416            let end = snapshot.len().min(end + 1);
2417            cursor.seek(&start, Bias::Right, &());
2418            while let Some(item) = cursor.item() {
2419                if *cursor.start() >= end {
2420                    break;
2421                }
2422                if item.hunk_info().is_some() {
2423                    return true;
2424                }
2425                cursor.next(&());
2426            }
2427        }
2428        false
2429    }
2430
2431    pub fn expand_or_collapse_diff_hunks_inner(
2432        &mut self,
2433        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2434        expand: bool,
2435        cx: &mut Context<Self>,
2436    ) {
2437        if self.all_diff_hunks_expanded && !expand {
2438            return;
2439        }
2440        self.sync(cx);
2441        let mut snapshot = self.snapshot.borrow_mut();
2442        let mut excerpt_edits = Vec::new();
2443        for (range, end_excerpt_id) in ranges {
2444            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2445                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2446                    continue;
2447                }
2448                let start = Anchor::in_buffer(
2449                    diff_hunk.excerpt_id,
2450                    diff_hunk.buffer_id,
2451                    diff_hunk.buffer_range.start,
2452                );
2453                let end = Anchor::in_buffer(
2454                    diff_hunk.excerpt_id,
2455                    diff_hunk.buffer_id,
2456                    diff_hunk.buffer_range.end,
2457                );
2458                let start = snapshot.excerpt_offset_for_anchor(&start);
2459                let end = snapshot.excerpt_offset_for_anchor(&end);
2460                excerpt_edits.push(text::Edit {
2461                    old: start..end,
2462                    new: start..end,
2463                });
2464            }
2465        }
2466
2467        self.sync_diff_transforms(
2468            &mut snapshot,
2469            excerpt_edits,
2470            DiffChangeKind::ExpandOrCollapseHunks { expand },
2471        );
2472        cx.emit(Event::DiffHunksToggled);
2473        cx.emit(Event::Edited {
2474            singleton_buffer_edited: false,
2475            edited_buffer: None,
2476        });
2477    }
2478
2479    pub fn expand_or_collapse_diff_hunks(
2480        &mut self,
2481        ranges: Vec<Range<Anchor>>,
2482        expand: bool,
2483        cx: &mut Context<Self>,
2484    ) {
2485        let snapshot = self.snapshot.borrow().clone();
2486        let ranges = ranges.iter().map(move |range| {
2487            let end_excerpt_id = range.end.excerpt_id;
2488            let range = range.to_point(&snapshot);
2489            let mut peek_end = range.end;
2490            if range.end.row < snapshot.max_row().0 {
2491                peek_end = Point::new(range.end.row + 1, 0);
2492            };
2493            (range.start..peek_end, end_excerpt_id)
2494        });
2495        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2496    }
2497
2498    pub fn resize_excerpt(
2499        &mut self,
2500        id: ExcerptId,
2501        range: Range<text::Anchor>,
2502        cx: &mut Context<Self>,
2503    ) {
2504        self.sync(cx);
2505
2506        let mut snapshot = self.snapshot.borrow_mut();
2507        let locator = snapshot.excerpt_locator_for_id(id);
2508        let mut new_excerpts = SumTree::default();
2509        let mut cursor = snapshot
2510            .excerpts
2511            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2512        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2513
2514        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2515        new_excerpts.append(prefix, &());
2516
2517        let mut excerpt = cursor.item().unwrap().clone();
2518        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2519
2520        excerpt.range.context.start = range.start;
2521        excerpt.range.context.end = range.end;
2522        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2523
2524        excerpt.text_summary = excerpt
2525            .buffer
2526            .text_summary_for_range(excerpt.range.context.clone());
2527
2528        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2529        let old_start_offset = cursor.start().1;
2530        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2531        let edit = Edit {
2532            old: old_start_offset..old_start_offset + old_text_len,
2533            new: new_start_offset..new_start_offset + new_text_len,
2534        };
2535
2536        if let Some(last_edit) = edits.last_mut() {
2537            if last_edit.old.end == edit.old.start {
2538                last_edit.old.end = edit.old.end;
2539                last_edit.new.end = edit.new.end;
2540            } else {
2541                edits.push(edit);
2542            }
2543        } else {
2544            edits.push(edit);
2545        }
2546
2547        new_excerpts.push(excerpt, &());
2548
2549        cursor.next(&());
2550
2551        new_excerpts.append(cursor.suffix(&()), &());
2552
2553        drop(cursor);
2554        snapshot.excerpts = new_excerpts;
2555
2556        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2557        cx.emit(Event::Edited {
2558            singleton_buffer_edited: false,
2559            edited_buffer: None,
2560        });
2561        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2562        cx.notify();
2563    }
2564
2565    pub fn expand_excerpts(
2566        &mut self,
2567        ids: impl IntoIterator<Item = ExcerptId>,
2568        line_count: u32,
2569        direction: ExpandExcerptDirection,
2570        cx: &mut Context<Self>,
2571    ) {
2572        if line_count == 0 {
2573            return;
2574        }
2575        self.sync(cx);
2576        let mut snapshot = self.snapshot.borrow_mut();
2577
2578        let ids = ids.into_iter().collect::<Vec<_>>();
2579        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2580        let mut new_excerpts = SumTree::default();
2581        let mut cursor = snapshot
2582            .excerpts
2583            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2584        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2585
2586        for locator in &locators {
2587            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2588            new_excerpts.append(prefix, &());
2589
2590            let mut excerpt = cursor.item().unwrap().clone();
2591            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2592
2593            let up_line_count = if direction.should_expand_up() {
2594                line_count
2595            } else {
2596                0
2597            };
2598
2599            let start_row = excerpt
2600                .range
2601                .context
2602                .start
2603                .to_point(&excerpt.buffer)
2604                .row
2605                .saturating_sub(up_line_count);
2606            let start_point = Point::new(start_row, 0);
2607            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2608
2609            let down_line_count = if direction.should_expand_down() {
2610                line_count
2611            } else {
2612                0
2613            };
2614
2615            let mut end_point = excerpt.buffer.clip_point(
2616                excerpt.range.context.end.to_point(&excerpt.buffer)
2617                    + Point::new(down_line_count, 0),
2618                Bias::Left,
2619            );
2620            end_point.column = excerpt.buffer.line_len(end_point.row);
2621            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2622            excerpt.max_buffer_row = end_point.row;
2623
2624            excerpt.text_summary = excerpt
2625                .buffer
2626                .text_summary_for_range(excerpt.range.context.clone());
2627
2628            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2629            let old_start_offset = cursor.start().1;
2630            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2631            let edit = Edit {
2632                old: old_start_offset..old_start_offset + old_text_len,
2633                new: new_start_offset..new_start_offset + new_text_len,
2634            };
2635
2636            if let Some(last_edit) = edits.last_mut() {
2637                if last_edit.old.end == edit.old.start {
2638                    last_edit.old.end = edit.old.end;
2639                    last_edit.new.end = edit.new.end;
2640                } else {
2641                    edits.push(edit);
2642                }
2643            } else {
2644                edits.push(edit);
2645            }
2646
2647            new_excerpts.push(excerpt, &());
2648
2649            cursor.next(&());
2650        }
2651
2652        new_excerpts.append(cursor.suffix(&()), &());
2653
2654        drop(cursor);
2655        snapshot.excerpts = new_excerpts;
2656
2657        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2658        cx.emit(Event::Edited {
2659            singleton_buffer_edited: false,
2660            edited_buffer: None,
2661        });
2662        cx.emit(Event::ExcerptsExpanded { ids });
2663        cx.notify();
2664    }
2665
2666    fn sync(&self, cx: &App) {
2667        let mut snapshot = self.snapshot.borrow_mut();
2668        let mut excerpts_to_edit = Vec::new();
2669        let mut non_text_state_updated = false;
2670        let mut is_dirty = false;
2671        let mut has_deleted_file = false;
2672        let mut has_conflict = false;
2673        let mut edited = false;
2674        let mut buffers = self.buffers.borrow_mut();
2675        for buffer_state in buffers.values_mut() {
2676            let buffer = buffer_state.buffer.read(cx);
2677            let version = buffer.version();
2678            let non_text_state_update_count = buffer.non_text_state_update_count();
2679
2680            let buffer_edited = version.changed_since(&buffer_state.last_version);
2681            let buffer_non_text_state_updated =
2682                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2683            if buffer_edited || buffer_non_text_state_updated {
2684                buffer_state.last_version = version;
2685                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2686                excerpts_to_edit.extend(
2687                    buffer_state
2688                        .excerpts
2689                        .iter()
2690                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2691                );
2692            }
2693
2694            edited |= buffer_edited;
2695            non_text_state_updated |= buffer_non_text_state_updated;
2696            is_dirty |= buffer.is_dirty();
2697            has_deleted_file |= buffer
2698                .file()
2699                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2700            has_conflict |= buffer.has_conflict();
2701        }
2702        if edited {
2703            snapshot.edit_count += 1;
2704        }
2705        if non_text_state_updated {
2706            snapshot.non_text_state_update_count += 1;
2707        }
2708        snapshot.is_dirty = is_dirty;
2709        snapshot.has_deleted_file = has_deleted_file;
2710        snapshot.has_conflict = has_conflict;
2711
2712        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2713
2714        let mut edits = Vec::new();
2715        let mut new_excerpts = SumTree::default();
2716        let mut cursor = snapshot
2717            .excerpts
2718            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2719
2720        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2721            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2722            let old_excerpt = cursor.item().unwrap();
2723            let buffer = buffer.read(cx);
2724            let buffer_id = buffer.remote_id();
2725
2726            let mut new_excerpt;
2727            if buffer_edited {
2728                edits.extend(
2729                    buffer
2730                        .edits_since_in_range::<usize>(
2731                            old_excerpt.buffer.version(),
2732                            old_excerpt.range.context.clone(),
2733                        )
2734                        .map(|edit| {
2735                            let excerpt_old_start = cursor.start().1;
2736                            let excerpt_new_start =
2737                                ExcerptOffset::new(new_excerpts.summary().text.len);
2738                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2739                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2740                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2741                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2742                            Edit {
2743                                old: old_start..old_end,
2744                                new: new_start..new_end,
2745                            }
2746                        }),
2747                );
2748
2749                new_excerpt = Excerpt::new(
2750                    old_excerpt.id,
2751                    locator.clone(),
2752                    buffer_id,
2753                    buffer.snapshot(),
2754                    old_excerpt.range.clone(),
2755                    old_excerpt.has_trailing_newline,
2756                );
2757            } else {
2758                new_excerpt = old_excerpt.clone();
2759                new_excerpt.buffer = buffer.snapshot();
2760            }
2761
2762            new_excerpts.push(new_excerpt, &());
2763            cursor.next(&());
2764        }
2765        new_excerpts.append(cursor.suffix(&()), &());
2766
2767        drop(cursor);
2768        snapshot.excerpts = new_excerpts;
2769
2770        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2771    }
2772
2773    fn sync_diff_transforms(
2774        &self,
2775        snapshot: &mut MultiBufferSnapshot,
2776        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2777        change_kind: DiffChangeKind,
2778    ) {
2779        if excerpt_edits.is_empty() {
2780            return;
2781        }
2782
2783        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2784        let mut old_diff_transforms = snapshot
2785            .diff_transforms
2786            .cursor::<(ExcerptOffset, usize)>(&());
2787        let mut new_diff_transforms = SumTree::default();
2788        let mut old_expanded_hunks = HashSet::default();
2789        let mut output_edits = Vec::new();
2790        let mut output_delta = 0_isize;
2791        let mut at_transform_boundary = true;
2792        let mut end_of_current_insert = None;
2793
2794        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2795        while let Some(edit) = excerpt_edits.next() {
2796            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2797            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2798                excerpts.prev(&());
2799            }
2800
2801            // Keep any transforms that are before the edit.
2802            if at_transform_boundary {
2803                at_transform_boundary = false;
2804                let transforms_before_edit =
2805                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2806                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2807                if let Some(transform) = old_diff_transforms.item() {
2808                    if old_diff_transforms.end(&()).0 == edit.old.start
2809                        && old_diff_transforms.start().0 < edit.old.start
2810                    {
2811                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2812                        old_diff_transforms.next(&());
2813                    }
2814                }
2815            }
2816
2817            // Compute the start of the edit in output coordinates.
2818            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2819            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2820            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2821
2822            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2823                &edit,
2824                &mut excerpts,
2825                &mut old_diff_transforms,
2826                &mut new_diff_transforms,
2827                &mut end_of_current_insert,
2828                &mut old_expanded_hunks,
2829                &snapshot,
2830                change_kind,
2831            );
2832
2833            // Compute the end of the edit in output coordinates.
2834            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2835            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2836            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2837            let edit_new_end =
2838                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2839            let output_edit = Edit {
2840                old: edit_old_start..edit_old_end,
2841                new: edit_new_start..edit_new_end,
2842            };
2843
2844            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2845            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2846            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2847                output_edits.push(output_edit);
2848            }
2849
2850            // If this is the last edit that intersects the current diff transform,
2851            // then recreate the content up to the end of this transform, to prepare
2852            // for reusing additional slices of the old transforms.
2853            if excerpt_edits.peek().map_or(true, |next_edit| {
2854                next_edit.old.start >= old_diff_transforms.end(&()).0
2855            }) {
2856                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2857                    && match old_diff_transforms.item() {
2858                        Some(DiffTransform::BufferContent {
2859                            inserted_hunk_info: Some(hunk),
2860                            ..
2861                        }) => excerpts.item().is_some_and(|excerpt| {
2862                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2863                        }),
2864                        _ => true,
2865                    };
2866
2867                let mut excerpt_offset = edit.new.end;
2868                if !keep_next_old_transform {
2869                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2870                    old_diff_transforms.next(&());
2871                }
2872
2873                old_expanded_hunks.clear();
2874                self.push_buffer_content_transform(
2875                    &snapshot,
2876                    &mut new_diff_transforms,
2877                    excerpt_offset,
2878                    end_of_current_insert,
2879                );
2880                at_transform_boundary = true;
2881            }
2882        }
2883
2884        // Keep any transforms that are after the last edit.
2885        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2886
2887        // Ensure there's always at least one buffer content transform.
2888        if new_diff_transforms.is_empty() {
2889            new_diff_transforms.push(
2890                DiffTransform::BufferContent {
2891                    summary: Default::default(),
2892                    inserted_hunk_info: None,
2893                },
2894                &(),
2895            );
2896        }
2897
2898        self.subscriptions.publish(output_edits);
2899        drop(old_diff_transforms);
2900        drop(excerpts);
2901        snapshot.diff_transforms = new_diff_transforms;
2902        snapshot.edit_count += 1;
2903
2904        #[cfg(any(test, feature = "test-support"))]
2905        snapshot.check_invariants();
2906    }
2907
2908    #[allow(clippy::too_many_arguments)]
2909    fn recompute_diff_transforms_for_edit(
2910        &self,
2911        edit: &Edit<TypedOffset<Excerpt>>,
2912        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2913        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2914        new_diff_transforms: &mut SumTree<DiffTransform>,
2915        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2916        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2917        snapshot: &MultiBufferSnapshot,
2918        change_kind: DiffChangeKind,
2919    ) -> bool {
2920        log::trace!(
2921            "recomputing diff transform for edit {:?} => {:?}",
2922            edit.old.start.value..edit.old.end.value,
2923            edit.new.start.value..edit.new.end.value
2924        );
2925
2926        // Record which hunks were previously expanded.
2927        while let Some(item) = old_diff_transforms.item() {
2928            if let Some(hunk_info) = item.hunk_info() {
2929                log::trace!(
2930                    "previously expanded hunk at {}",
2931                    old_diff_transforms.start().0
2932                );
2933                old_expanded_hunks.insert(hunk_info);
2934            }
2935            if old_diff_transforms.end(&()).0 > edit.old.end {
2936                break;
2937            }
2938            old_diff_transforms.next(&());
2939        }
2940
2941        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2942        if old_expanded_hunks.is_empty()
2943            && change_kind == DiffChangeKind::BufferEdited
2944            && !self.all_diff_hunks_expanded
2945        {
2946            return false;
2947        }
2948
2949        // Visit each excerpt that intersects the edit.
2950        let mut did_expand_hunks = false;
2951        while let Some(excerpt) = excerpts.item() {
2952            // Recompute the expanded hunks in the portion of the excerpt that
2953            // intersects the edit.
2954            if let Some((diff, base_text)) = snapshot
2955                .diffs
2956                .get(&excerpt.buffer_id)
2957                .and_then(|diff| Some((diff, diff.base_text()?)))
2958            {
2959                let buffer = &excerpt.buffer;
2960                let excerpt_start = *excerpts.start();
2961                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2962                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2963                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2964                let edit_buffer_start =
2965                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2966                let edit_buffer_end =
2967                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2968                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2969                let edit_anchor_range =
2970                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2971
2972                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2973                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2974
2975                    let hunk_info = DiffTransformHunkInfo {
2976                        excerpt_id: excerpt.id,
2977                        hunk_start_anchor: hunk.buffer_range.start,
2978                        hunk_secondary_status: hunk.secondary_status,
2979                    };
2980                    if hunk_buffer_range.start < excerpt_buffer_start {
2981                        log::trace!("skipping hunk that starts before excerpt");
2982                        continue;
2983                    }
2984
2985                    let hunk_excerpt_start = excerpt_start
2986                        + ExcerptOffset::new(
2987                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2988                        );
2989                    let hunk_excerpt_end = excerpt_end.min(
2990                        excerpt_start
2991                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2992                    );
2993
2994                    self.push_buffer_content_transform(
2995                        snapshot,
2996                        new_diff_transforms,
2997                        hunk_excerpt_start,
2998                        *end_of_current_insert,
2999                    );
3000
3001                    // For every existing hunk, determine if it was previously expanded
3002                    // and if it should currently be expanded.
3003                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3004                    let should_expand_hunk = match &change_kind {
3005                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3006                            self.all_diff_hunks_expanded || was_previously_expanded
3007                        }
3008                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3009                            let intersects = hunk_buffer_range.is_empty()
3010                                || hunk_buffer_range.end > edit_buffer_start;
3011                            if *expand {
3012                                intersects
3013                                    || was_previously_expanded
3014                                    || self.all_diff_hunks_expanded
3015                            } else {
3016                                !intersects
3017                                    && (was_previously_expanded || self.all_diff_hunks_expanded)
3018                            }
3019                        }
3020                        _ => was_previously_expanded || self.all_diff_hunks_expanded,
3021                    };
3022
3023                    if should_expand_hunk {
3024                        did_expand_hunks = true;
3025                        log::trace!(
3026                            "expanding hunk {:?}, excerpt:{:?}",
3027                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3028                            excerpt.id
3029                        );
3030
3031                        if !hunk.diff_base_byte_range.is_empty()
3032                            && hunk_buffer_range.start >= edit_buffer_start
3033                            && hunk_buffer_range.start <= excerpt_buffer_end
3034                        {
3035                            let mut text_cursor =
3036                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3037                            let mut base_text_summary =
3038                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3039
3040                            let mut has_trailing_newline = false;
3041                            if base_text_summary.last_line_chars > 0 {
3042                                base_text_summary += TextSummary::newline();
3043                                has_trailing_newline = true;
3044                            }
3045
3046                            new_diff_transforms.push(
3047                                DiffTransform::DeletedHunk {
3048                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3049                                    summary: base_text_summary,
3050                                    buffer_id: excerpt.buffer_id,
3051                                    hunk_info,
3052                                    has_trailing_newline,
3053                                },
3054                                &(),
3055                            );
3056                        }
3057
3058                        if !hunk_buffer_range.is_empty() {
3059                            *end_of_current_insert =
3060                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3061                        }
3062                    }
3063                }
3064            }
3065
3066            if excerpts.end(&()) <= edit.new.end {
3067                excerpts.next(&());
3068            } else {
3069                break;
3070            }
3071        }
3072
3073        did_expand_hunks || !old_expanded_hunks.is_empty()
3074    }
3075
3076    fn append_diff_transforms(
3077        &self,
3078        new_transforms: &mut SumTree<DiffTransform>,
3079        subtree: SumTree<DiffTransform>,
3080    ) {
3081        if let Some(DiffTransform::BufferContent {
3082            inserted_hunk_info,
3083            summary,
3084        }) = subtree.first()
3085        {
3086            if self.extend_last_buffer_content_transform(
3087                new_transforms,
3088                *inserted_hunk_info,
3089                *summary,
3090            ) {
3091                let mut cursor = subtree.cursor::<()>(&());
3092                cursor.next(&());
3093                cursor.next(&());
3094                new_transforms.append(cursor.suffix(&()), &());
3095                return;
3096            }
3097        }
3098        new_transforms.append(subtree, &());
3099    }
3100
3101    fn push_diff_transform(
3102        &self,
3103        new_transforms: &mut SumTree<DiffTransform>,
3104        transform: DiffTransform,
3105    ) {
3106        if let DiffTransform::BufferContent {
3107            inserted_hunk_info: inserted_hunk_anchor,
3108            summary,
3109        } = transform
3110        {
3111            if self.extend_last_buffer_content_transform(
3112                new_transforms,
3113                inserted_hunk_anchor,
3114                summary,
3115            ) {
3116                return;
3117            }
3118        }
3119        new_transforms.push(transform, &());
3120    }
3121
3122    fn push_buffer_content_transform(
3123        &self,
3124        old_snapshot: &MultiBufferSnapshot,
3125        new_transforms: &mut SumTree<DiffTransform>,
3126        end_offset: ExcerptOffset,
3127        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3128    ) {
3129        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3130            (end_offset.min(insertion_end_offset), Some(hunk_info))
3131        });
3132        let unchanged_region = [(end_offset, None)];
3133
3134        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3135        {
3136            let start_offset = new_transforms.summary().excerpt_len();
3137            if end_offset <= start_offset {
3138                continue;
3139            }
3140            let summary_to_add = old_snapshot
3141                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3142
3143            if !self.extend_last_buffer_content_transform(
3144                new_transforms,
3145                inserted_hunk_info,
3146                summary_to_add,
3147            ) {
3148                new_transforms.push(
3149                    DiffTransform::BufferContent {
3150                        summary: summary_to_add,
3151                        inserted_hunk_info,
3152                    },
3153                    &(),
3154                )
3155            }
3156        }
3157    }
3158
3159    fn extend_last_buffer_content_transform(
3160        &self,
3161        new_transforms: &mut SumTree<DiffTransform>,
3162        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3163        summary_to_add: TextSummary,
3164    ) -> bool {
3165        let mut did_extend = false;
3166        new_transforms.update_last(
3167            |last_transform| {
3168                if let DiffTransform::BufferContent {
3169                    summary,
3170                    inserted_hunk_info: inserted_hunk_anchor,
3171                } = last_transform
3172                {
3173                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3174                        *summary += summary_to_add;
3175                        did_extend = true;
3176                    }
3177                }
3178            },
3179            &(),
3180        );
3181        did_extend
3182    }
3183}
3184
3185#[cfg(any(test, feature = "test-support"))]
3186impl MultiBuffer {
3187    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3188        let buffer = cx.new(|cx| Buffer::local(text, cx));
3189        cx.new(|cx| Self::singleton(buffer, cx))
3190    }
3191
3192    pub fn build_multi<const COUNT: usize>(
3193        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3194        cx: &mut gpui::App,
3195    ) -> Entity<Self> {
3196        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3197        for (text, ranges) in excerpts {
3198            let buffer = cx.new(|cx| Buffer::local(text, cx));
3199            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3200                context: range,
3201                primary: None,
3202            });
3203            multi.update(cx, |multi, cx| {
3204                multi.push_excerpts(buffer, excerpt_ranges, cx)
3205            });
3206        }
3207
3208        multi
3209    }
3210
3211    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3212        cx.new(|cx| Self::singleton(buffer, cx))
3213    }
3214
3215    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3216        cx.new(|cx| {
3217            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3218            let mutation_count = rng.gen_range(1..=5);
3219            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3220            multibuffer
3221        })
3222    }
3223
3224    pub fn randomly_edit(
3225        &mut self,
3226        rng: &mut impl rand::Rng,
3227        edit_count: usize,
3228        cx: &mut Context<Self>,
3229    ) {
3230        use util::RandomCharIter;
3231
3232        let snapshot = self.read(cx);
3233        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3234        let mut last_end = None;
3235        for _ in 0..edit_count {
3236            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3237                break;
3238            }
3239
3240            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3241            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3242            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3243            last_end = Some(end);
3244
3245            let mut range = start..end;
3246            if rng.gen_bool(0.2) {
3247                mem::swap(&mut range.start, &mut range.end);
3248            }
3249
3250            let new_text_len = rng.gen_range(0..10);
3251            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3252
3253            edits.push((range, new_text.into()));
3254        }
3255        log::info!("mutating multi-buffer with {:?}", edits);
3256        drop(snapshot);
3257
3258        self.edit(edits, None, cx);
3259    }
3260
3261    pub fn randomly_edit_excerpts(
3262        &mut self,
3263        rng: &mut impl rand::Rng,
3264        mutation_count: usize,
3265        cx: &mut Context<Self>,
3266    ) {
3267        use rand::prelude::*;
3268        use std::env;
3269        use util::RandomCharIter;
3270
3271        let max_excerpts = env::var("MAX_EXCERPTS")
3272            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3273            .unwrap_or(5);
3274
3275        let mut buffers = Vec::new();
3276        for _ in 0..mutation_count {
3277            if rng.gen_bool(0.05) {
3278                log::info!("Clearing multi-buffer");
3279                self.clear(cx);
3280                continue;
3281            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3282                let ids = self.excerpt_ids();
3283                let mut excerpts = HashSet::default();
3284                for _ in 0..rng.gen_range(0..ids.len()) {
3285                    excerpts.extend(ids.choose(rng).copied());
3286                }
3287
3288                let line_count = rng.gen_range(0..5);
3289
3290                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3291
3292                self.expand_excerpts(
3293                    excerpts.iter().cloned(),
3294                    line_count,
3295                    ExpandExcerptDirection::UpAndDown,
3296                    cx,
3297                );
3298                continue;
3299            }
3300
3301            let excerpt_ids = self.excerpt_ids();
3302            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3303                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3304                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3305                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3306                    let buffer = buffers.last().unwrap().read(cx);
3307                    log::info!(
3308                        "Creating new buffer {} with text: {:?}",
3309                        buffer.remote_id(),
3310                        buffer.text()
3311                    );
3312                    buffers.last().unwrap().clone()
3313                } else {
3314                    self.buffers
3315                        .borrow()
3316                        .values()
3317                        .choose(rng)
3318                        .unwrap()
3319                        .buffer
3320                        .clone()
3321                };
3322
3323                let buffer = buffer_handle.read(cx);
3324                let buffer_text = buffer.text();
3325                let ranges = (0..rng.gen_range(0..5))
3326                    .map(|_| {
3327                        let end_ix =
3328                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3329                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3330                        ExcerptRange {
3331                            context: start_ix..end_ix,
3332                            primary: None,
3333                        }
3334                    })
3335                    .collect::<Vec<_>>();
3336                log::info!(
3337                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3338                    buffer_handle.read(cx).remote_id(),
3339                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3340                    ranges
3341                        .iter()
3342                        .map(|r| &buffer_text[r.context.clone()])
3343                        .collect::<Vec<_>>()
3344                );
3345
3346                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3347                log::info!("Inserted with ids: {:?}", excerpt_id);
3348            } else {
3349                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3350                let mut excerpts_to_remove = excerpt_ids
3351                    .choose_multiple(rng, remove_count)
3352                    .cloned()
3353                    .collect::<Vec<_>>();
3354                let snapshot = self.snapshot.borrow();
3355                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3356                drop(snapshot);
3357                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3358                self.remove_excerpts(excerpts_to_remove, cx);
3359            }
3360        }
3361    }
3362
3363    pub fn randomly_mutate(
3364        &mut self,
3365        rng: &mut impl rand::Rng,
3366        mutation_count: usize,
3367        cx: &mut Context<Self>,
3368    ) {
3369        use rand::prelude::*;
3370
3371        if rng.gen_bool(0.7) || self.singleton {
3372            let buffer = self
3373                .buffers
3374                .borrow()
3375                .values()
3376                .choose(rng)
3377                .map(|state| state.buffer.clone());
3378
3379            if let Some(buffer) = buffer {
3380                buffer.update(cx, |buffer, cx| {
3381                    if rng.gen() {
3382                        buffer.randomly_edit(rng, mutation_count, cx);
3383                    } else {
3384                        buffer.randomly_undo_redo(rng, cx);
3385                    }
3386                });
3387            } else {
3388                self.randomly_edit(rng, mutation_count, cx);
3389            }
3390        } else {
3391            self.randomly_edit_excerpts(rng, mutation_count, cx);
3392        }
3393
3394        self.check_invariants(cx);
3395    }
3396
3397    fn check_invariants(&self, cx: &App) {
3398        self.read(cx).check_invariants();
3399    }
3400}
3401
3402impl EventEmitter<Event> for MultiBuffer {}
3403
3404impl MultiBufferSnapshot {
3405    pub fn text(&self) -> String {
3406        self.chunks(0..self.len(), false)
3407            .map(|chunk| chunk.text)
3408            .collect()
3409    }
3410
3411    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3412        self.reversed_chunks_in_range(0..position.to_offset(self))
3413            .flat_map(|c| c.chars().rev())
3414    }
3415
3416    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3417        let mut cursor = self.cursor::<usize>();
3418        cursor.seek(&range.end);
3419        let current_chunks = cursor.region().as_ref().map(|region| {
3420            let start_overshoot = range.start.saturating_sub(region.range.start);
3421            let end_overshoot = range.end - region.range.start;
3422            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3423            let start = region.buffer_range.start + start_overshoot;
3424            region.buffer.reversed_chunks_in_range(start..end)
3425        });
3426        ReversedMultiBufferChunks {
3427            cursor,
3428            current_chunks,
3429            start: range.start,
3430            offset: range.end,
3431        }
3432    }
3433
3434    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3435        let offset = position.to_offset(self);
3436        self.text_for_range(offset..self.len())
3437            .flat_map(|chunk| chunk.chars())
3438    }
3439
3440    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3441        self.chunks(range, false).map(|chunk| chunk.text)
3442    }
3443
3444    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3445        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3446            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3447    }
3448
3449    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3450    where
3451        T: ToOffset,
3452    {
3453        let position = position.to_offset(self);
3454        position == self.clip_offset(position, Bias::Left)
3455            && self
3456                .bytes_in_range(position..self.len())
3457                .flatten()
3458                .copied()
3459                .take(needle.len())
3460                .eq(needle.bytes())
3461    }
3462
3463    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3464        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3465    }
3466
3467    pub fn diff_hunks_in_range<T: ToPoint>(
3468        &self,
3469        range: Range<T>,
3470    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3471        let query_range = range.start.to_point(self)..range.end.to_point(self);
3472        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3473            let diff = self.diffs.get(&buffer.remote_id())?;
3474            let buffer_start = buffer.anchor_before(buffer_range.start);
3475            let buffer_end = buffer.anchor_after(buffer_range.end);
3476            Some(
3477                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3478                    .map(|hunk| {
3479                        (
3480                            Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
3481                            hunk,
3482                        )
3483                    }),
3484            )
3485        })
3486        .filter_map(move |(range, hunk, excerpt)| {
3487            if range.start != range.end
3488                && range.end == query_range.start
3489                && !hunk.row_range.is_empty()
3490            {
3491                return None;
3492            }
3493            let end_row = if range.end.column == 0 {
3494                range.end.row
3495            } else {
3496                range.end.row + 1
3497            };
3498            Some(MultiBufferDiffHunk {
3499                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3500                buffer_id: excerpt.buffer_id,
3501                excerpt_id: excerpt.id,
3502                buffer_range: hunk.buffer_range.clone(),
3503                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3504                secondary_status: hunk.secondary_status,
3505                secondary_diff_base_byte_range: hunk.secondary_diff_base_byte_range,
3506            })
3507        })
3508    }
3509
3510    pub fn excerpt_ids_for_range<T: ToOffset>(
3511        &self,
3512        range: Range<T>,
3513    ) -> impl Iterator<Item = ExcerptId> + '_ {
3514        let range = range.start.to_offset(self)..range.end.to_offset(self);
3515        let mut cursor = self.cursor::<usize>();
3516        cursor.seek(&range.start);
3517        std::iter::from_fn(move || {
3518            let region = cursor.region()?;
3519            if region.range.start >= range.end {
3520                return None;
3521            }
3522            cursor.next_excerpt();
3523            Some(region.excerpt.id)
3524        })
3525    }
3526
3527    pub fn buffer_ids_for_range<T: ToOffset>(
3528        &self,
3529        range: Range<T>,
3530    ) -> impl Iterator<Item = BufferId> + '_ {
3531        let range = range.start.to_offset(self)..range.end.to_offset(self);
3532        let mut cursor = self.cursor::<usize>();
3533        cursor.seek(&range.start);
3534        std::iter::from_fn(move || {
3535            let region = cursor.region()?;
3536            if region.range.start >= range.end {
3537                return None;
3538            }
3539            cursor.next_excerpt();
3540            Some(region.excerpt.buffer_id)
3541        })
3542    }
3543
3544    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3545        &self,
3546        ranges: impl Iterator<Item = Range<T>>,
3547    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3548        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3549    }
3550
3551    pub fn range_to_buffer_ranges<T: ToOffset>(
3552        &self,
3553        range: Range<T>,
3554    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3555        let start = range.start.to_offset(&self);
3556        let end = range.end.to_offset(&self);
3557
3558        let mut cursor = self.cursor::<usize>();
3559        cursor.seek(&start);
3560
3561        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3562        while let Some(region) = cursor.region() {
3563            if region.range.start > end {
3564                break;
3565            }
3566            if region.is_main_buffer {
3567                let start_overshoot = start.saturating_sub(region.range.start);
3568                let end_overshoot = end.saturating_sub(region.range.start);
3569                let start = region
3570                    .buffer_range
3571                    .end
3572                    .min(region.buffer_range.start + start_overshoot);
3573                let end = region
3574                    .buffer_range
3575                    .end
3576                    .min(region.buffer_range.start + end_overshoot);
3577                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3578                    *excerpt_id == region.excerpt.id && prev_range.end == start
3579                }) {
3580                    prev.1.end = end;
3581                } else {
3582                    result.push((region.buffer, start..end, region.excerpt.id));
3583                }
3584            }
3585            cursor.next();
3586        }
3587        result
3588    }
3589
3590    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3591        &self,
3592        range: Range<T>,
3593    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3594        let start = range.start.to_offset(&self);
3595        let end = range.end.to_offset(&self);
3596
3597        let mut cursor = self.cursor::<usize>();
3598        cursor.seek(&start);
3599
3600        std::iter::from_fn(move || {
3601            let region = cursor.region()?;
3602            if region.range.start > end {
3603                return None;
3604            }
3605            let start_overshoot = start.saturating_sub(region.range.start);
3606            let end_overshoot = end.saturating_sub(region.range.start);
3607            let start = region
3608                .buffer_range
3609                .end
3610                .min(region.buffer_range.start + start_overshoot);
3611            let end = region
3612                .buffer_range
3613                .end
3614                .min(region.buffer_range.start + end_overshoot);
3615
3616            let region_excerpt_id = region.excerpt.id;
3617            let deleted_hunk_anchor = if region.is_main_buffer {
3618                None
3619            } else {
3620                Some(self.anchor_before(region.range.start))
3621            };
3622            let result = (
3623                region.buffer,
3624                start..end,
3625                region_excerpt_id,
3626                deleted_hunk_anchor,
3627            );
3628            cursor.next();
3629            Some(result)
3630        })
3631    }
3632
3633    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3634    /// coordinates.
3635    ///
3636    /// The given callback will be called for every excerpt intersecting the given range. It will
3637    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3638    /// The callback should return an iterator of metadata items from that buffer, each paired
3639    /// with a buffer range.
3640    ///
3641    /// The returned iterator yields each of these metadata items, paired with its range in
3642    /// multi-buffer coordinates.
3643    fn lift_buffer_metadata<'a, D, M, I>(
3644        &'a self,
3645        query_range: Range<D>,
3646        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3647    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3648    where
3649        I: Iterator<Item = (Range<D>, M)> + 'a,
3650        D: TextDimension + Ord + Sub<D, Output = D>,
3651    {
3652        let max_position = D::from_text_summary(&self.text_summary());
3653        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3654        let mut cursor = self.cursor::<D>();
3655
3656        // Find the excerpt and buffer offset where the given range ends.
3657        cursor.seek(&query_range.end);
3658        let mut range_end = None;
3659        while let Some(region) = cursor.region() {
3660            if region.is_main_buffer {
3661                let mut buffer_end = region.buffer_range.start;
3662                let overshoot = if query_range.end > region.range.start {
3663                    query_range.end - region.range.start
3664                } else {
3665                    D::default()
3666                };
3667                buffer_end.add_assign(&overshoot);
3668                range_end = Some((region.excerpt.id, buffer_end));
3669                break;
3670            }
3671            cursor.next();
3672        }
3673
3674        cursor.seek(&query_range.start);
3675
3676        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3677            if region.range.start > D::zero(&()) {
3678                cursor.prev()
3679            }
3680        }
3681
3682        iter::from_fn(move || loop {
3683            let excerpt = cursor.excerpt()?;
3684
3685            // If we have already retrieved metadata for this excerpt, continue to use it.
3686            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3687                .as_mut()
3688                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3689            {
3690                Some(metadata)
3691            }
3692            // Otherwise, compute the intersection of the input range with the excerpt's range,
3693            // and retrieve the metadata for the resulting range.
3694            else {
3695                let region = cursor.region()?;
3696                let mut buffer_start;
3697                if region.is_main_buffer {
3698                    buffer_start = region.buffer_range.start;
3699                    if query_range.start > region.range.start {
3700                        let overshoot = query_range.start - region.range.start;
3701                        buffer_start.add_assign(&overshoot);
3702                    }
3703                    buffer_start = buffer_start.min(region.buffer_range.end);
3704                } else {
3705                    buffer_start = cursor.main_buffer_position()?;
3706                };
3707                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3708                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3709                    if excerpt.id == end_excerpt_id {
3710                        buffer_end = buffer_end.min(end_buffer_offset);
3711                    }
3712                }
3713
3714                if let Some(iterator) =
3715                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3716                {
3717                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3718                } else {
3719                    None
3720                }
3721            };
3722
3723            // Visit each metadata item.
3724            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3725            {
3726                // Find the multibuffer regions that contain the start and end of
3727                // the metadata item's range.
3728                if metadata_buffer_range.start > D::default() {
3729                    while let Some(region) = cursor.region() {
3730                        if region.is_main_buffer
3731                            && (region.buffer_range.end >= metadata_buffer_range.start
3732                                || cursor.is_at_end_of_excerpt())
3733                        {
3734                            break;
3735                        }
3736                        cursor.next();
3737                    }
3738                }
3739                let start_region = cursor.region()?;
3740                while let Some(region) = cursor.region() {
3741                    if region.is_main_buffer
3742                        && (region.buffer_range.end > metadata_buffer_range.end
3743                            || cursor.is_at_end_of_excerpt())
3744                    {
3745                        break;
3746                    }
3747                    cursor.next();
3748                }
3749                let end_region = cursor.region();
3750
3751                // Convert the metadata item's range into multibuffer coordinates.
3752                let mut start_position = start_region.range.start;
3753                let region_buffer_start = start_region.buffer_range.start;
3754                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3755                {
3756                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3757                    start_position = start_position.min(start_region.range.end);
3758                }
3759
3760                let mut end_position = max_position;
3761                if let Some(end_region) = &end_region {
3762                    end_position = end_region.range.start;
3763                    debug_assert!(end_region.is_main_buffer);
3764                    let region_buffer_start = end_region.buffer_range.start;
3765                    if metadata_buffer_range.end > region_buffer_start {
3766                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3767                    }
3768                    end_position = end_position.min(end_region.range.end);
3769                }
3770
3771                if start_position <= query_range.end && end_position >= query_range.start {
3772                    return Some((start_position..end_position, metadata, excerpt));
3773                }
3774            }
3775            // When there are no more metadata items for this excerpt, move to the next excerpt.
3776            else {
3777                current_excerpt_metadata.take();
3778                cursor.next_excerpt();
3779            }
3780        })
3781    }
3782
3783    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3784        let offset = position.to_offset(self);
3785
3786        // Go to the region containing the given offset.
3787        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3788        cursor.seek(&DimensionPair {
3789            key: offset,
3790            value: None,
3791        });
3792        let mut region = cursor.region()?;
3793        if region.range.start.key == offset || !region.is_main_buffer {
3794            cursor.prev();
3795            region = cursor.region()?;
3796        }
3797
3798        // Find the corresponding buffer offset.
3799        let overshoot = if region.is_main_buffer {
3800            offset - region.range.start.key
3801        } else {
3802            0
3803        };
3804        let mut max_buffer_offset = region
3805            .buffer
3806            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3807
3808        loop {
3809            let excerpt = cursor.excerpt()?;
3810            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3811            let buffer_offset = excerpt_end.min(max_buffer_offset);
3812            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3813            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3814
3815            if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3816                for hunk in diff.hunks_intersecting_range_rev(
3817                    excerpt.range.context.start..buffer_end,
3818                    &excerpt.buffer,
3819                ) {
3820                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3821                    if hunk.row_range.end >= buffer_end_row {
3822                        continue;
3823                    }
3824
3825                    let hunk_start = Point::new(hunk.row_range.start, 0);
3826                    let hunk_end = Point::new(hunk.row_range.end, 0);
3827
3828                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3829                        key: hunk_range.start,
3830                        value: None,
3831                    });
3832
3833                    let mut region = cursor.region()?;
3834                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3835                    {
3836                        cursor.prev();
3837                        region = cursor.region()?;
3838                    }
3839
3840                    let overshoot = if region.is_main_buffer {
3841                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3842                    } else {
3843                        Point::zero()
3844                    };
3845                    let start = region.range.start.value.unwrap() + overshoot;
3846
3847                    while let Some(region) = cursor.region() {
3848                        if !region.is_main_buffer
3849                            || region.buffer_range.end.value.unwrap() <= hunk_end
3850                        {
3851                            cursor.next();
3852                        } else {
3853                            break;
3854                        }
3855                    }
3856
3857                    let end = if let Some(region) = cursor.region() {
3858                        let overshoot = if region.is_main_buffer {
3859                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3860                        } else {
3861                            Point::zero()
3862                        };
3863                        region.range.start.value.unwrap() + overshoot
3864                    } else {
3865                        self.max_point()
3866                    };
3867
3868                    return Some(MultiBufferDiffHunk {
3869                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3870                        buffer_id: excerpt.buffer_id,
3871                        excerpt_id: excerpt.id,
3872                        buffer_range: hunk.buffer_range.clone(),
3873                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3874                        secondary_status: hunk.secondary_status,
3875                        secondary_diff_base_byte_range: hunk.secondary_diff_base_byte_range,
3876                    });
3877                }
3878            }
3879
3880            cursor.prev_excerpt();
3881            max_buffer_offset = usize::MAX;
3882        }
3883    }
3884
3885    pub fn has_diff_hunks(&self) -> bool {
3886        self.diffs.values().any(|diff| !diff.is_empty())
3887    }
3888
3889    pub fn surrounding_word<T: ToOffset>(
3890        &self,
3891        start: T,
3892        for_completion: bool,
3893    ) -> (Range<usize>, Option<CharKind>) {
3894        let mut start = start.to_offset(self);
3895        let mut end = start;
3896        let mut next_chars = self.chars_at(start).peekable();
3897        let mut prev_chars = self.reversed_chars_at(start).peekable();
3898
3899        let classifier = self
3900            .char_classifier_at(start)
3901            .for_completion(for_completion);
3902
3903        let word_kind = cmp::max(
3904            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3905            next_chars.peek().copied().map(|c| classifier.kind(c)),
3906        );
3907
3908        for ch in prev_chars {
3909            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3910                start -= ch.len_utf8();
3911            } else {
3912                break;
3913            }
3914        }
3915
3916        for ch in next_chars {
3917            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3918                end += ch.len_utf8();
3919            } else {
3920                break;
3921            }
3922        }
3923
3924        (start..end, word_kind)
3925    }
3926
3927    pub fn is_singleton(&self) -> bool {
3928        self.singleton
3929    }
3930
3931    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3932        if self.singleton {
3933            self.excerpts
3934                .iter()
3935                .next()
3936                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3937        } else {
3938            None
3939        }
3940    }
3941
3942    pub fn len(&self) -> usize {
3943        self.diff_transforms.summary().output.len
3944    }
3945
3946    pub fn is_empty(&self) -> bool {
3947        self.excerpts.summary().text.len == 0
3948    }
3949
3950    pub fn widest_line_number(&self) -> u32 {
3951        self.excerpts.summary().widest_line_number + 1
3952    }
3953
3954    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3955        let range = range.start.to_offset(self)..range.end.to_offset(self);
3956        let mut excerpts = self.cursor::<usize>();
3957        excerpts.seek(&range.start);
3958
3959        let mut chunk;
3960        let mut has_trailing_newline;
3961        let excerpt_bytes;
3962        if let Some(region) = excerpts.region() {
3963            let mut bytes = region.buffer.bytes_in_range(
3964                region.buffer_range.start + range.start - region.range.start
3965                    ..(region.buffer_range.start + range.end - region.range.start)
3966                        .min(region.buffer_range.end),
3967            );
3968            chunk = bytes.next().unwrap_or(&[][..]);
3969            excerpt_bytes = Some(bytes);
3970            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3971            if chunk.is_empty() && has_trailing_newline {
3972                chunk = b"\n";
3973                has_trailing_newline = false;
3974            }
3975        } else {
3976            chunk = &[][..];
3977            excerpt_bytes = None;
3978            has_trailing_newline = false;
3979        };
3980
3981        MultiBufferBytes {
3982            range,
3983            cursor: excerpts,
3984            excerpt_bytes,
3985            has_trailing_newline,
3986            chunk,
3987        }
3988    }
3989
3990    pub fn reversed_bytes_in_range<T: ToOffset>(
3991        &self,
3992        range: Range<T>,
3993    ) -> ReversedMultiBufferBytes {
3994        let range = range.start.to_offset(self)..range.end.to_offset(self);
3995        let mut chunks = self.reversed_chunks_in_range(range.clone());
3996        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3997        ReversedMultiBufferBytes {
3998            range,
3999            chunks,
4000            chunk,
4001        }
4002    }
4003
4004    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4005        let mut cursor = self.cursor::<Point>();
4006        cursor.seek(&Point::new(start_row.0, 0));
4007        let mut result = MultiBufferRows {
4008            point: Point::new(0, 0),
4009            is_empty: self.excerpts.is_empty(),
4010            cursor,
4011        };
4012        result.seek(start_row);
4013        result
4014    }
4015
4016    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4017        let mut chunks = MultiBufferChunks {
4018            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4019            range: 0..0,
4020            excerpts: self.excerpts.cursor(&()),
4021            diff_transforms: self.diff_transforms.cursor(&()),
4022            diffs: &self.diffs,
4023            diff_base_chunks: None,
4024            excerpt_chunks: None,
4025            buffer_chunk: None,
4026            language_aware,
4027        };
4028        let range = range.start.to_offset(self)..range.end.to_offset(self);
4029        chunks.seek(range);
4030        chunks
4031    }
4032
4033    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4034        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4035    }
4036
4037    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4038        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4039    }
4040
4041    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4042        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4043    }
4044
4045    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4046        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4047            buffer.clip_point_utf16(Unclipped(point), bias)
4048        })
4049    }
4050
4051    pub fn offset_to_point(&self, offset: usize) -> Point {
4052        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4053    }
4054
4055    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4056        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4057    }
4058
4059    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4060        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4061    }
4062
4063    pub fn point_to_offset(&self, point: Point) -> usize {
4064        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4065    }
4066
4067    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4068        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4069    }
4070
4071    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4072        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4073    }
4074
4075    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4076        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4077    }
4078
4079    fn clip_dimension<D>(
4080        &self,
4081        position: D,
4082        bias: Bias,
4083        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4084    ) -> D
4085    where
4086        D: TextDimension + Ord + Sub<D, Output = D>,
4087    {
4088        let mut cursor = self.cursor();
4089        cursor.seek(&position);
4090        if let Some(region) = cursor.region() {
4091            if position >= region.range.end {
4092                return region.range.end;
4093            }
4094            let overshoot = position - region.range.start;
4095            let mut buffer_position = region.buffer_range.start;
4096            buffer_position.add_assign(&overshoot);
4097            let clipped_buffer_position =
4098                clip_buffer_position(&region.buffer, buffer_position, bias);
4099            let mut position = region.range.start;
4100            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4101            position
4102        } else {
4103            D::from_text_summary(&self.text_summary())
4104        }
4105    }
4106
4107    fn convert_dimension<D1, D2>(
4108        &self,
4109        key: D1,
4110        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4111    ) -> D2
4112    where
4113        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4114        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4115    {
4116        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4117        cursor.seek(&DimensionPair { key, value: None });
4118        if let Some(region) = cursor.region() {
4119            if key >= region.range.end.key {
4120                return region.range.end.value.unwrap();
4121            }
4122            let start_key = region.range.start.key;
4123            let start_value = region.range.start.value.unwrap();
4124            let buffer_start_key = region.buffer_range.start.key;
4125            let buffer_start_value = region.buffer_range.start.value.unwrap();
4126            let mut buffer_key = buffer_start_key;
4127            buffer_key.add_assign(&(key - start_key));
4128            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4129            let mut result = start_value;
4130            result.add_assign(&(buffer_value - buffer_start_value));
4131            result
4132        } else {
4133            D2::from_text_summary(&self.text_summary())
4134        }
4135    }
4136
4137    pub fn point_to_buffer_offset<T: ToOffset>(
4138        &self,
4139        point: T,
4140    ) -> Option<(&BufferSnapshot, usize)> {
4141        let offset = point.to_offset(self);
4142        let mut cursor = self.cursor::<usize>();
4143        cursor.seek(&offset);
4144        let region = cursor.region()?;
4145        let overshoot = offset - region.range.start;
4146        let buffer_offset = region.buffer_range.start + overshoot;
4147        Some((region.buffer, buffer_offset))
4148    }
4149
4150    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4151        let mut cursor = self.cursor::<Point>();
4152        cursor.seek(&point);
4153        let region = cursor.region()?;
4154        let overshoot = point - region.range.start;
4155        let buffer_offset = region.buffer_range.start + overshoot;
4156        Some((region.buffer, buffer_offset, region.is_main_buffer))
4157    }
4158
4159    pub fn suggested_indents(
4160        &self,
4161        rows: impl IntoIterator<Item = u32>,
4162        cx: &App,
4163    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4164        let mut result = BTreeMap::new();
4165
4166        let mut rows_for_excerpt = Vec::new();
4167        let mut cursor = self.cursor::<Point>();
4168        let mut rows = rows.into_iter().peekable();
4169        let mut prev_row = u32::MAX;
4170        let mut prev_language_indent_size = IndentSize::default();
4171
4172        while let Some(row) = rows.next() {
4173            cursor.seek(&Point::new(row, 0));
4174            let Some(region) = cursor.region() else {
4175                continue;
4176            };
4177
4178            // Retrieve the language and indent size once for each disjoint region being indented.
4179            let single_indent_size = if row.saturating_sub(1) == prev_row {
4180                prev_language_indent_size
4181            } else {
4182                region
4183                    .buffer
4184                    .language_indent_size_at(Point::new(row, 0), cx)
4185            };
4186            prev_language_indent_size = single_indent_size;
4187            prev_row = row;
4188
4189            let start_buffer_row = region.buffer_range.start.row;
4190            let start_multibuffer_row = region.range.start.row;
4191            let end_multibuffer_row = region.range.end.row;
4192
4193            rows_for_excerpt.push(row);
4194            while let Some(next_row) = rows.peek().copied() {
4195                if end_multibuffer_row > next_row {
4196                    rows_for_excerpt.push(next_row);
4197                    rows.next();
4198                } else {
4199                    break;
4200                }
4201            }
4202
4203            let buffer_rows = rows_for_excerpt
4204                .drain(..)
4205                .map(|row| start_buffer_row + row - start_multibuffer_row);
4206            let buffer_indents = region
4207                .buffer
4208                .suggested_indents(buffer_rows, single_indent_size);
4209            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4210                (
4211                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4212                    indent,
4213                )
4214            });
4215            result.extend(multibuffer_indents);
4216        }
4217
4218        result
4219    }
4220
4221    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4222        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4223            let mut size = buffer.indent_size_for_line(range.start.row);
4224            size.len = size
4225                .len
4226                .min(range.end.column)
4227                .saturating_sub(range.start.column);
4228            size
4229        } else {
4230            IndentSize::spaces(0)
4231        }
4232    }
4233
4234    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4235        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4236            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4237        } else {
4238            LineIndent::spaces(0)
4239        }
4240    }
4241
4242    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4243        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4244
4245        if self.settings_at(0, cx).extend_comment_on_newline {
4246            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4247                let delimiters = language_scope.line_comment_prefixes();
4248                for delimiter in delimiters {
4249                    if *self
4250                        .chars_at(Point::new(row.0, indent.len() as u32))
4251                        .take(delimiter.chars().count())
4252                        .collect::<String>()
4253                        .as_str()
4254                        == **delimiter
4255                    {
4256                        indent.push_str(&delimiter);
4257                        break;
4258                    }
4259                }
4260            }
4261        }
4262
4263        indent
4264    }
4265
4266    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4267    where
4268        T: ToOffset,
4269    {
4270        for char in self.reversed_chars_at(position) {
4271            if !char.is_whitespace() {
4272                return false;
4273            }
4274            if char == '\n' {
4275                return true;
4276            }
4277        }
4278        return true;
4279    }
4280
4281    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4282        while row.0 > 0 {
4283            row.0 -= 1;
4284            if !self.is_line_blank(row) {
4285                return Some(row);
4286            }
4287        }
4288        None
4289    }
4290
4291    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4292        if let Some((_, range)) = self.buffer_line_for_row(row) {
4293            range.end.column - range.start.column
4294        } else {
4295            0
4296        }
4297    }
4298
4299    pub fn buffer_line_for_row(
4300        &self,
4301        row: MultiBufferRow,
4302    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4303        let mut cursor = self.cursor::<Point>();
4304        let point = Point::new(row.0, 0);
4305        cursor.seek(&point);
4306        let region = cursor.region()?;
4307        let overshoot = point.min(region.range.end) - region.range.start;
4308        let buffer_point = region.buffer_range.start + overshoot;
4309        if buffer_point.row > region.buffer_range.end.row {
4310            return None;
4311        }
4312        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4313        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4314            .min(region.buffer_range.end);
4315        Some((region.buffer, line_start..line_end))
4316    }
4317
4318    pub fn max_point(&self) -> Point {
4319        self.text_summary().lines
4320    }
4321
4322    pub fn max_row(&self) -> MultiBufferRow {
4323        MultiBufferRow(self.text_summary().lines.row)
4324    }
4325
4326    pub fn text_summary(&self) -> TextSummary {
4327        self.diff_transforms.summary().output
4328    }
4329
4330    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4331    where
4332        D: TextDimension,
4333        O: ToOffset,
4334    {
4335        let range = range.start.to_offset(self)..range.end.to_offset(self);
4336        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4337        cursor.seek(&range.start, Bias::Right, &());
4338
4339        let Some(first_transform) = cursor.item() else {
4340            return D::from_text_summary(&TextSummary::default());
4341        };
4342
4343        let diff_transform_start = cursor.start().0;
4344        let diff_transform_end = cursor.end(&()).0;
4345        let diff_start = range.start;
4346        let start_overshoot = diff_start - diff_transform_start;
4347        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4348
4349        let mut result = match first_transform {
4350            DiffTransform::BufferContent { .. } => {
4351                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4352                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4353                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4354            }
4355            DiffTransform::DeletedHunk {
4356                buffer_id,
4357                base_text_byte_range,
4358                has_trailing_newline,
4359                ..
4360            } => {
4361                let buffer_start = base_text_byte_range.start + start_overshoot;
4362                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4363                let Some(base_text) = self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4364                else {
4365                    panic!("{:?} is in non-existent deleted hunk", range.start)
4366                };
4367
4368                let include_trailing_newline =
4369                    *has_trailing_newline && range.end >= diff_transform_end;
4370                if include_trailing_newline {
4371                    buffer_end -= 1;
4372                }
4373
4374                let mut summary =
4375                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4376
4377                if include_trailing_newline {
4378                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4379                }
4380
4381                summary
4382            }
4383        };
4384        if range.end < diff_transform_end {
4385            return result;
4386        }
4387
4388        cursor.next(&());
4389        result.add_assign(&D::from_text_summary(&cursor.summary(
4390            &range.end,
4391            Bias::Right,
4392            &(),
4393        )));
4394
4395        let Some(last_transform) = cursor.item() else {
4396            return result;
4397        };
4398
4399        let overshoot = range.end - cursor.start().0;
4400        let suffix = match last_transform {
4401            DiffTransform::BufferContent { .. } => {
4402                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4403                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4404            }
4405            DiffTransform::DeletedHunk {
4406                base_text_byte_range,
4407                buffer_id,
4408                has_trailing_newline,
4409                ..
4410            } => {
4411                let buffer_end = base_text_byte_range.start + overshoot;
4412                let Some(base_text) = self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4413                else {
4414                    panic!("{:?} is in non-existent deleted hunk", range.end)
4415                };
4416
4417                let mut suffix = base_text
4418                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4419                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4420                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4421                }
4422                suffix
4423            }
4424        };
4425
4426        result.add_assign(&suffix);
4427        result
4428    }
4429
4430    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4431    where
4432        D: TextDimension,
4433    {
4434        // let mut range = range.start..range.end;
4435        let mut summary = D::zero(&());
4436        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4437        cursor.seek(&range.start, Bias::Right, &());
4438        if let Some(excerpt) = cursor.item() {
4439            let mut end_before_newline = cursor.end(&());
4440            if excerpt.has_trailing_newline {
4441                end_before_newline -= ExcerptOffset::new(1);
4442            }
4443
4444            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4445            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4446            let end_in_excerpt =
4447                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4448            summary.add_assign(
4449                &excerpt
4450                    .buffer
4451                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4452            );
4453
4454            if range.end > end_before_newline {
4455                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4456            }
4457
4458            cursor.next(&());
4459        }
4460
4461        if range.end > *cursor.start() {
4462            summary.add_assign(
4463                &cursor
4464                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4465                    .0,
4466            );
4467            if let Some(excerpt) = cursor.item() {
4468                range.end = cmp::max(*cursor.start(), range.end);
4469
4470                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4471                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4472                summary.add_assign(
4473                    &excerpt
4474                        .buffer
4475                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4476                );
4477            }
4478        }
4479
4480        summary
4481    }
4482
4483    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4484    where
4485        D: TextDimension + Ord + Sub<D, Output = D>,
4486    {
4487        self.summaries_for_anchors([anchor])[0]
4488    }
4489
4490    fn resolve_summary_for_anchor<D>(
4491        &self,
4492        anchor: &Anchor,
4493        excerpt_position: D,
4494        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4495    ) -> D
4496    where
4497        D: TextDimension + Ord + Sub<D, Output = D>,
4498    {
4499        loop {
4500            let transform_end_position = diff_transforms.end(&()).0 .0;
4501            let at_transform_end =
4502                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4503            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4504                diff_transforms.next(&());
4505                continue;
4506            }
4507
4508            let mut position = diff_transforms.start().1 .0;
4509            match diff_transforms.item() {
4510                Some(DiffTransform::DeletedHunk {
4511                    buffer_id,
4512                    base_text_byte_range,
4513                    ..
4514                }) => {
4515                    let mut in_deleted_hunk = false;
4516                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4517                        if let Some(base_text) =
4518                            self.diffs.get(buffer_id).and_then(|diff| diff.base_text())
4519                        {
4520                            if base_text.can_resolve(&diff_base_anchor) {
4521                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4522                                if base_text_offset >= base_text_byte_range.start
4523                                    && base_text_offset <= base_text_byte_range.end
4524                                {
4525                                    let position_in_hunk = base_text
4526                                        .text_summary_for_range::<D, _>(
4527                                            base_text_byte_range.start..base_text_offset,
4528                                        );
4529                                    position.add_assign(&position_in_hunk);
4530                                    in_deleted_hunk = true;
4531                                } else if at_transform_end {
4532                                    diff_transforms.next(&());
4533                                    continue;
4534                                }
4535                            }
4536                        }
4537                    }
4538                    if !in_deleted_hunk {
4539                        position = diff_transforms.end(&()).1 .0;
4540                    }
4541                }
4542                _ => {
4543                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4544                        diff_transforms.next(&());
4545                        continue;
4546                    }
4547                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4548                    position.add_assign(&overshoot);
4549                }
4550            }
4551
4552            return position;
4553        }
4554    }
4555
4556    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4557        let mut cursor = self
4558            .excerpts
4559            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4560        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4561
4562        cursor.seek(&Some(locator), Bias::Left, &());
4563        if cursor.item().is_none() {
4564            cursor.next(&());
4565        }
4566
4567        let mut position = cursor.start().1;
4568        if let Some(excerpt) = cursor.item() {
4569            if excerpt.id == anchor.excerpt_id {
4570                let excerpt_buffer_start = excerpt
4571                    .buffer
4572                    .offset_for_anchor(&excerpt.range.context.start);
4573                let excerpt_buffer_end =
4574                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4575                let buffer_position = cmp::min(
4576                    excerpt_buffer_end,
4577                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4578                );
4579                if buffer_position > excerpt_buffer_start {
4580                    position.value += buffer_position - excerpt_buffer_start;
4581                }
4582            }
4583        }
4584        position
4585    }
4586
4587    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4588    where
4589        D: TextDimension + Ord + Sub<D, Output = D>,
4590        I: 'a + IntoIterator<Item = &'a Anchor>,
4591    {
4592        let mut anchors = anchors.into_iter().peekable();
4593        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4594        let mut diff_transforms_cursor = self
4595            .diff_transforms
4596            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4597        diff_transforms_cursor.next(&());
4598
4599        let mut summaries = Vec::new();
4600        while let Some(anchor) = anchors.peek() {
4601            let excerpt_id = anchor.excerpt_id;
4602            let excerpt_anchors = iter::from_fn(|| {
4603                let anchor = anchors.peek()?;
4604                if anchor.excerpt_id == excerpt_id {
4605                    Some(anchors.next().unwrap())
4606                } else {
4607                    None
4608                }
4609            });
4610
4611            let locator = self.excerpt_locator_for_id(excerpt_id);
4612            cursor.seek_forward(locator, Bias::Left, &());
4613            if cursor.item().is_none() {
4614                cursor.next(&());
4615            }
4616
4617            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4618            if let Some(excerpt) = cursor.item() {
4619                if excerpt.id != excerpt_id {
4620                    let position = self.resolve_summary_for_anchor(
4621                        &Anchor::min(),
4622                        excerpt_start_position,
4623                        &mut diff_transforms_cursor,
4624                    );
4625                    summaries.extend(excerpt_anchors.map(|_| position));
4626                    continue;
4627                }
4628                let excerpt_buffer_start =
4629                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4630                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4631                for (buffer_summary, anchor) in excerpt
4632                    .buffer
4633                    .summaries_for_anchors_with_payload::<D, _, _>(
4634                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4635                    )
4636                {
4637                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4638                    let mut position = excerpt_start_position;
4639                    if summary > excerpt_buffer_start {
4640                        position.add_assign(&(summary - excerpt_buffer_start));
4641                    }
4642
4643                    if position > diff_transforms_cursor.start().0 .0 {
4644                        diff_transforms_cursor.seek_forward(
4645                            &ExcerptDimension(position),
4646                            Bias::Left,
4647                            &(),
4648                        );
4649                    }
4650
4651                    summaries.push(self.resolve_summary_for_anchor(
4652                        anchor,
4653                        position,
4654                        &mut diff_transforms_cursor,
4655                    ));
4656                }
4657            } else {
4658                diff_transforms_cursor.seek_forward(
4659                    &ExcerptDimension(excerpt_start_position),
4660                    Bias::Left,
4661                    &(),
4662                );
4663                let position = self.resolve_summary_for_anchor(
4664                    &Anchor::max(),
4665                    excerpt_start_position,
4666                    &mut diff_transforms_cursor,
4667                );
4668                summaries.extend(excerpt_anchors.map(|_| position));
4669            }
4670        }
4671
4672        summaries
4673    }
4674
4675    pub fn dimensions_from_points<'a, D>(
4676        &'a self,
4677        points: impl 'a + IntoIterator<Item = Point>,
4678    ) -> impl 'a + Iterator<Item = D>
4679    where
4680        D: TextDimension + Sub<D, Output = D>,
4681    {
4682        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4683        cursor.seek(&DimensionPair {
4684            key: Point::default(),
4685            value: None,
4686        });
4687        let mut points = points.into_iter();
4688        iter::from_fn(move || {
4689            let point = points.next()?;
4690
4691            cursor.seek_forward(&DimensionPair {
4692                key: point,
4693                value: None,
4694            });
4695
4696            if let Some(region) = cursor.region() {
4697                let overshoot = point - region.range.start.key;
4698                let buffer_point = region.buffer_range.start.key + overshoot;
4699                let mut position = region.range.start.value.unwrap();
4700                position.add_assign(
4701                    &region
4702                        .buffer
4703                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4704                );
4705                return Some(position);
4706            } else {
4707                return Some(D::from_text_summary(&self.text_summary()));
4708            }
4709        })
4710    }
4711
4712    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4713    where
4714        I: 'a + IntoIterator<Item = &'a Anchor>,
4715    {
4716        let mut anchors = anchors.into_iter().enumerate().peekable();
4717        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4718        cursor.next(&());
4719
4720        let mut result = Vec::new();
4721
4722        while let Some((_, anchor)) = anchors.peek() {
4723            let old_excerpt_id = anchor.excerpt_id;
4724
4725            // Find the location where this anchor's excerpt should be.
4726            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4727            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4728
4729            if cursor.item().is_none() {
4730                cursor.next(&());
4731            }
4732
4733            let next_excerpt = cursor.item();
4734            let prev_excerpt = cursor.prev_item();
4735
4736            // Process all of the anchors for this excerpt.
4737            while let Some((_, anchor)) = anchors.peek() {
4738                if anchor.excerpt_id != old_excerpt_id {
4739                    break;
4740                }
4741                let (anchor_ix, anchor) = anchors.next().unwrap();
4742                let mut anchor = *anchor;
4743
4744                // Leave min and max anchors unchanged if invalid or
4745                // if the old excerpt still exists at this location
4746                let mut kept_position = next_excerpt
4747                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4748                    || old_excerpt_id == ExcerptId::max()
4749                    || old_excerpt_id == ExcerptId::min();
4750
4751                // If the old excerpt no longer exists at this location, then attempt to
4752                // find an equivalent position for this anchor in an adjacent excerpt.
4753                if !kept_position {
4754                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4755                        if excerpt.contains(&anchor) {
4756                            anchor.excerpt_id = excerpt.id;
4757                            kept_position = true;
4758                            break;
4759                        }
4760                    }
4761                }
4762
4763                // If there's no adjacent excerpt that contains the anchor's position,
4764                // then report that the anchor has lost its position.
4765                if !kept_position {
4766                    anchor = if let Some(excerpt) = next_excerpt {
4767                        let mut text_anchor = excerpt
4768                            .range
4769                            .context
4770                            .start
4771                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4772                        if text_anchor
4773                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4774                            .is_gt()
4775                        {
4776                            text_anchor = excerpt.range.context.end;
4777                        }
4778                        Anchor {
4779                            buffer_id: Some(excerpt.buffer_id),
4780                            excerpt_id: excerpt.id,
4781                            text_anchor,
4782                            diff_base_anchor: None,
4783                        }
4784                    } else if let Some(excerpt) = prev_excerpt {
4785                        let mut text_anchor = excerpt
4786                            .range
4787                            .context
4788                            .end
4789                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4790                        if text_anchor
4791                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4792                            .is_lt()
4793                        {
4794                            text_anchor = excerpt.range.context.start;
4795                        }
4796                        Anchor {
4797                            buffer_id: Some(excerpt.buffer_id),
4798                            excerpt_id: excerpt.id,
4799                            text_anchor,
4800                            diff_base_anchor: None,
4801                        }
4802                    } else if anchor.text_anchor.bias == Bias::Left {
4803                        Anchor::min()
4804                    } else {
4805                        Anchor::max()
4806                    };
4807                }
4808
4809                result.push((anchor_ix, anchor, kept_position));
4810            }
4811        }
4812        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4813        result
4814    }
4815
4816    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4817        self.anchor_at(position, Bias::Left)
4818    }
4819
4820    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4821        self.anchor_at(position, Bias::Right)
4822    }
4823
4824    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4825        let offset = position.to_offset(self);
4826
4827        // Find the given position in the diff transforms. Determine the corresponding
4828        // offset in the excerpts, and whether the position is within a deleted hunk.
4829        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4830        diff_transforms.seek(&offset, Bias::Right, &());
4831
4832        if offset == diff_transforms.start().0 && bias == Bias::Left {
4833            if let Some(prev_item) = diff_transforms.prev_item() {
4834                match prev_item {
4835                    DiffTransform::DeletedHunk { .. } => {
4836                        diff_transforms.prev(&());
4837                    }
4838                    _ => {}
4839                }
4840            }
4841        }
4842        let offset_in_transform = offset - diff_transforms.start().0;
4843        let mut excerpt_offset = diff_transforms.start().1;
4844        let mut diff_base_anchor = None;
4845        if let Some(DiffTransform::DeletedHunk {
4846            buffer_id,
4847            base_text_byte_range,
4848            has_trailing_newline,
4849            ..
4850        }) = diff_transforms.item()
4851        {
4852            let base_text = self
4853                .diffs
4854                .get(buffer_id)
4855                .and_then(|diff| diff.base_text())
4856                .expect("missing diff base");
4857            if offset_in_transform > base_text_byte_range.len() {
4858                debug_assert!(*has_trailing_newline);
4859                bias = Bias::Right;
4860            } else {
4861                diff_base_anchor = Some(
4862                    base_text.anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4863                );
4864                bias = Bias::Left;
4865            }
4866        } else {
4867            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4868        };
4869
4870        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4871            return Anchor {
4872                buffer_id: Some(buffer_id),
4873                excerpt_id: *excerpt_id,
4874                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4875                diff_base_anchor,
4876            };
4877        }
4878
4879        let mut excerpts = self
4880            .excerpts
4881            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4882        excerpts.seek(&excerpt_offset, Bias::Right, &());
4883        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4884            excerpts.prev(&());
4885        }
4886        if let Some(excerpt) = excerpts.item() {
4887            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4888            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4889                overshoot -= 1;
4890                bias = Bias::Right;
4891            }
4892
4893            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4894            let text_anchor =
4895                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4896            Anchor {
4897                buffer_id: Some(excerpt.buffer_id),
4898                excerpt_id: excerpt.id,
4899                text_anchor,
4900                diff_base_anchor,
4901            }
4902        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4903            Anchor::min()
4904        } else {
4905            Anchor::max()
4906        }
4907    }
4908
4909    /// Returns an anchor for the given excerpt and text anchor,
4910    /// returns None if the excerpt_id is no longer valid.
4911    pub fn anchor_in_excerpt(
4912        &self,
4913        excerpt_id: ExcerptId,
4914        text_anchor: text::Anchor,
4915    ) -> Option<Anchor> {
4916        let locator = self.excerpt_locator_for_id(excerpt_id);
4917        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4918        cursor.seek(locator, Bias::Left, &());
4919        if let Some(excerpt) = cursor.item() {
4920            if excerpt.id == excerpt_id {
4921                let text_anchor = excerpt.clip_anchor(text_anchor);
4922                drop(cursor);
4923                return Some(Anchor {
4924                    buffer_id: Some(excerpt.buffer_id),
4925                    excerpt_id,
4926                    text_anchor,
4927                    diff_base_anchor: None,
4928                });
4929            }
4930        }
4931        None
4932    }
4933
4934    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4935        Some(self.excerpt(excerpt_id)?.range.context.clone())
4936    }
4937
4938    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4939        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4940            true
4941        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4942            excerpt.buffer.can_resolve(&anchor.text_anchor)
4943        } else {
4944            false
4945        }
4946    }
4947
4948    pub fn excerpts(
4949        &self,
4950    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4951        self.excerpts
4952            .iter()
4953            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4954    }
4955
4956    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4957        let excerpts = self.excerpts.cursor(&());
4958        let diff_transforms = self.diff_transforms.cursor(&());
4959        MultiBufferCursor {
4960            excerpts,
4961            diff_transforms,
4962            diffs: &self.diffs,
4963            cached_region: None,
4964        }
4965    }
4966
4967    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4968        let start_locator = self.excerpt_locator_for_id(id);
4969        let mut excerpts = self
4970            .excerpts
4971            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4972        excerpts.seek(&Some(start_locator), Bias::Left, &());
4973        excerpts.prev(&());
4974
4975        let mut diff_transforms = self
4976            .diff_transforms
4977            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4978        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4979        if diff_transforms.end(&()).1 < excerpts.start().1 {
4980            diff_transforms.next(&());
4981        }
4982
4983        let excerpt = excerpts.item()?;
4984        Some(MultiBufferExcerpt {
4985            excerpt,
4986            offset: diff_transforms.start().0 .0,
4987            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4988            excerpt_offset: excerpts.start().1.clone(),
4989            diff_transforms,
4990        })
4991    }
4992
4993    pub fn excerpt_boundaries_in_range<R, T>(
4994        &self,
4995        range: R,
4996    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4997    where
4998        R: RangeBounds<T>,
4999        T: ToOffset,
5000    {
5001        let start_offset;
5002        let start = match range.start_bound() {
5003            Bound::Included(start) => {
5004                start_offset = start.to_offset(self);
5005                Bound::Included(start_offset)
5006            }
5007            Bound::Excluded(_) => {
5008                panic!("not supported")
5009            }
5010            Bound::Unbounded => {
5011                start_offset = 0;
5012                Bound::Unbounded
5013            }
5014        };
5015        let end = match range.end_bound() {
5016            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5017            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5018            Bound::Unbounded => Bound::Unbounded,
5019        };
5020        let bounds = (start, end);
5021
5022        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5023        cursor.seek(&DimensionPair {
5024            key: start_offset,
5025            value: None,
5026        });
5027
5028        if cursor
5029            .region()
5030            .is_some_and(|region| bounds.contains(&region.range.start.key))
5031        {
5032            cursor.prev_excerpt();
5033        } else {
5034            cursor.seek_to_start_of_current_excerpt();
5035        }
5036        let mut prev_region = cursor.region();
5037
5038        cursor.next_excerpt();
5039
5040        let mut visited_end = false;
5041        iter::from_fn(move || loop {
5042            if self.singleton {
5043                return None;
5044            }
5045
5046            let next_region = cursor.region();
5047            cursor.next_excerpt();
5048
5049            let next_region_start = if let Some(region) = &next_region {
5050                if !bounds.contains(&region.range.start.key) {
5051                    prev_region = next_region;
5052                    continue;
5053                }
5054                region.range.start.value.unwrap()
5055            } else {
5056                if !bounds.contains(&self.len()) {
5057                    return None;
5058                }
5059                self.max_point()
5060            };
5061            let next_region_end = if let Some(region) = cursor.region() {
5062                region.range.start.value.unwrap()
5063            } else {
5064                self.max_point()
5065            };
5066
5067            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5068                id: region.excerpt.id,
5069                buffer: region.excerpt.buffer.clone(),
5070                buffer_id: region.excerpt.buffer_id,
5071                range: region.excerpt.range.clone(),
5072                end_row: MultiBufferRow(next_region_start.row),
5073            });
5074
5075            let next = next_region.as_ref().map(|region| ExcerptInfo {
5076                id: region.excerpt.id,
5077                buffer: region.excerpt.buffer.clone(),
5078                buffer_id: region.excerpt.buffer_id,
5079                range: region.excerpt.range.clone(),
5080                end_row: if region.excerpt.has_trailing_newline {
5081                    MultiBufferRow(next_region_end.row - 1)
5082                } else {
5083                    MultiBufferRow(next_region_end.row)
5084                },
5085            });
5086
5087            if next.is_none() {
5088                if visited_end {
5089                    return None;
5090                } else {
5091                    visited_end = true;
5092                }
5093            }
5094
5095            let row = MultiBufferRow(next_region_start.row);
5096
5097            prev_region = next_region;
5098
5099            return Some(ExcerptBoundary { row, prev, next });
5100        })
5101    }
5102
5103    pub fn edit_count(&self) -> usize {
5104        self.edit_count
5105    }
5106
5107    pub fn non_text_state_update_count(&self) -> usize {
5108        self.non_text_state_update_count
5109    }
5110
5111    /// Returns the smallest enclosing bracket ranges containing the given range or
5112    /// None if no brackets contain range or the range is not contained in a single
5113    /// excerpt
5114    ///
5115    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5116    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5117        &self,
5118        range: Range<T>,
5119        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5120    ) -> Option<(Range<usize>, Range<usize>)> {
5121        let range = range.start.to_offset(self)..range.end.to_offset(self);
5122        let mut excerpt = self.excerpt_containing(range.clone())?;
5123        let buffer = excerpt.buffer();
5124        let excerpt_buffer_range = excerpt.buffer_range();
5125
5126        // Filter to ranges contained in the excerpt
5127        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5128            excerpt_buffer_range.contains(&open.start)
5129                && excerpt_buffer_range.contains(&close.end)
5130                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5131        };
5132
5133        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5134            excerpt.map_range_to_buffer(range),
5135            Some(&range_filter),
5136        )?;
5137
5138        Some((
5139            excerpt.map_range_from_buffer(open),
5140            excerpt.map_range_from_buffer(close),
5141        ))
5142    }
5143
5144    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5145    /// not contained in a single excerpt
5146    pub fn enclosing_bracket_ranges<T: ToOffset>(
5147        &self,
5148        range: Range<T>,
5149    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5150        let range = range.start.to_offset(self)..range.end.to_offset(self);
5151        let mut excerpt = self.excerpt_containing(range.clone())?;
5152
5153        Some(
5154            excerpt
5155                .buffer()
5156                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5157                .filter_map(move |pair| {
5158                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5159                        Some((
5160                            excerpt.map_range_from_buffer(pair.open_range),
5161                            excerpt.map_range_from_buffer(pair.close_range),
5162                        ))
5163                    } else {
5164                        None
5165                    }
5166                }),
5167        )
5168    }
5169
5170    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5171    /// not contained in a single excerpt
5172    pub fn text_object_ranges<T: ToOffset>(
5173        &self,
5174        range: Range<T>,
5175        options: TreeSitterOptions,
5176    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5177        let range = range.start.to_offset(self)..range.end.to_offset(self);
5178        self.excerpt_containing(range.clone())
5179            .map(|mut excerpt| {
5180                excerpt
5181                    .buffer()
5182                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5183                    .filter_map(move |(range, text_object)| {
5184                        if excerpt.contains_buffer_range(range.clone()) {
5185                            Some((excerpt.map_range_from_buffer(range), text_object))
5186                        } else {
5187                            None
5188                        }
5189                    })
5190            })
5191            .into_iter()
5192            .flatten()
5193    }
5194
5195    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5196    /// not contained in a single excerpt
5197    pub fn bracket_ranges<T: ToOffset>(
5198        &self,
5199        range: Range<T>,
5200    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5201        let range = range.start.to_offset(self)..range.end.to_offset(self);
5202        let mut excerpt = self.excerpt_containing(range.clone())?;
5203
5204        Some(
5205            excerpt
5206                .buffer()
5207                .bracket_ranges(excerpt.map_range_to_buffer(range))
5208                .filter_map(move |pair| {
5209                    let buffer_range = pair.open_range.start..pair.close_range.end;
5210                    if excerpt.contains_buffer_range(buffer_range) {
5211                        Some((
5212                            excerpt.map_range_from_buffer(pair.open_range),
5213                            excerpt.map_range_from_buffer(pair.close_range),
5214                        ))
5215                    } else {
5216                        None
5217                    }
5218                }),
5219        )
5220    }
5221
5222    pub fn redacted_ranges<'a, T: ToOffset>(
5223        &'a self,
5224        range: Range<T>,
5225        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5226    ) -> impl Iterator<Item = Range<usize>> + 'a {
5227        let range = range.start.to_offset(self)..range.end.to_offset(self);
5228        self.lift_buffer_metadata(range, move |buffer, range| {
5229            if redaction_enabled(buffer.file()) {
5230                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5231            } else {
5232                None
5233            }
5234        })
5235        .map(|(range, _, _)| range)
5236    }
5237
5238    pub fn runnable_ranges(
5239        &self,
5240        range: Range<Anchor>,
5241    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5242        let range = range.start.to_offset(self)..range.end.to_offset(self);
5243        self.lift_buffer_metadata(range, move |buffer, range| {
5244            Some(
5245                buffer
5246                    .runnable_ranges(range.clone())
5247                    .filter(move |runnable| {
5248                        runnable.run_range.start >= range.start
5249                            && runnable.run_range.end < range.end
5250                    })
5251                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5252            )
5253        })
5254        .map(|(run_range, runnable, _)| language::RunnableRange {
5255            run_range,
5256            ..runnable
5257        })
5258    }
5259
5260    pub fn line_indents(
5261        &self,
5262        start_row: MultiBufferRow,
5263        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5264    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5265        let max_point = self.max_point();
5266        let mut cursor = self.cursor::<Point>();
5267        cursor.seek(&Point::new(start_row.0, 0));
5268        iter::from_fn(move || {
5269            let mut region = cursor.region()?;
5270            while !buffer_filter(&region.excerpt.buffer) {
5271                cursor.next();
5272                region = cursor.region()?;
5273            }
5274            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5275            let buffer_start_row =
5276                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5277
5278            let buffer_end_row = if region.is_main_buffer
5279                && (region.has_trailing_newline || region.range.end == max_point)
5280            {
5281                region.buffer_range.end.row
5282            } else {
5283                region.buffer_range.end.row.saturating_sub(1)
5284            };
5285
5286            let line_indents = region
5287                .buffer
5288                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5289            cursor.next();
5290            return Some(line_indents.map(move |(buffer_row, indent)| {
5291                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5292                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5293            }));
5294        })
5295        .flatten()
5296    }
5297
5298    pub fn reversed_line_indents(
5299        &self,
5300        end_row: MultiBufferRow,
5301        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5302    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5303        let max_point = self.max_point();
5304        let mut cursor = self.cursor::<Point>();
5305        cursor.seek(&Point::new(end_row.0, 0));
5306        iter::from_fn(move || {
5307            let mut region = cursor.region()?;
5308            while !buffer_filter(&region.excerpt.buffer) {
5309                cursor.prev();
5310                region = cursor.region()?;
5311            }
5312
5313            let buffer_start_row = region.buffer_range.start.row;
5314            let buffer_end_row = if region.is_main_buffer
5315                && (region.has_trailing_newline || region.range.end == max_point)
5316            {
5317                region.buffer_range.end.row + 1
5318            } else {
5319                region.buffer_range.end.row
5320            };
5321
5322            let overshoot = end_row.0 - region.range.start.row;
5323            let buffer_end_row =
5324                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5325
5326            let line_indents = region
5327                .buffer
5328                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5329            cursor.prev();
5330            return Some(line_indents.map(move |(buffer_row, indent)| {
5331                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5332                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5333            }));
5334        })
5335        .flatten()
5336    }
5337
5338    pub async fn enclosing_indent(
5339        &self,
5340        mut target_row: MultiBufferRow,
5341    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5342        let max_row = MultiBufferRow(self.max_point().row);
5343        if target_row >= max_row {
5344            return None;
5345        }
5346
5347        let mut target_indent = self.line_indent_for_row(target_row);
5348
5349        // If the current row is at the start of an indented block, we want to return this
5350        // block as the enclosing indent.
5351        if !target_indent.is_line_empty() && target_row < max_row {
5352            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5353            if !next_line_indent.is_line_empty()
5354                && target_indent.raw_len() < next_line_indent.raw_len()
5355            {
5356                target_indent = next_line_indent;
5357                target_row.0 += 1;
5358            }
5359        }
5360
5361        const SEARCH_ROW_LIMIT: u32 = 25000;
5362        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5363        const YIELD_INTERVAL: u32 = 100;
5364
5365        let mut accessed_row_counter = 0;
5366
5367        // If there is a blank line at the current row, search for the next non indented lines
5368        if target_indent.is_line_empty() {
5369            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5370            let end =
5371                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5372
5373            let mut non_empty_line_above = None;
5374            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5375                if row < start {
5376                    break;
5377                }
5378                accessed_row_counter += 1;
5379                if accessed_row_counter == YIELD_INTERVAL {
5380                    accessed_row_counter = 0;
5381                    yield_now().await;
5382                }
5383                if !indent.is_line_empty() {
5384                    non_empty_line_above = Some((row, indent));
5385                    break;
5386                }
5387            }
5388
5389            let mut non_empty_line_below = None;
5390            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5391                if row > end {
5392                    break;
5393                }
5394                accessed_row_counter += 1;
5395                if accessed_row_counter == YIELD_INTERVAL {
5396                    accessed_row_counter = 0;
5397                    yield_now().await;
5398                }
5399                if !indent.is_line_empty() {
5400                    non_empty_line_below = Some((row, indent));
5401                    break;
5402                }
5403            }
5404
5405            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5406                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5407                    if above_indent.raw_len() >= below_indent.raw_len() {
5408                        (above_row, above_indent)
5409                    } else {
5410                        (below_row, below_indent)
5411                    }
5412                }
5413                (Some(above), None) => above,
5414                (None, Some(below)) => below,
5415                _ => return None,
5416            };
5417
5418            target_indent = indent;
5419            target_row = row;
5420        }
5421
5422        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5423        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5424
5425        let mut start_indent = None;
5426        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5427            if row < start {
5428                break;
5429            }
5430            accessed_row_counter += 1;
5431            if accessed_row_counter == YIELD_INTERVAL {
5432                accessed_row_counter = 0;
5433                yield_now().await;
5434            }
5435            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5436                start_indent = Some((row, indent));
5437                break;
5438            }
5439        }
5440        let (start_row, start_indent_size) = start_indent?;
5441
5442        let mut end_indent = (end, None);
5443        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5444            if row > end {
5445                break;
5446            }
5447            accessed_row_counter += 1;
5448            if accessed_row_counter == YIELD_INTERVAL {
5449                accessed_row_counter = 0;
5450                yield_now().await;
5451            }
5452            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5453                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5454                break;
5455            }
5456        }
5457        let (end_row, end_indent_size) = end_indent;
5458
5459        let indent = if let Some(end_indent_size) = end_indent_size {
5460            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5461                start_indent_size
5462            } else {
5463                end_indent_size
5464            }
5465        } else {
5466            start_indent_size
5467        };
5468
5469        Some((start_row..end_row, indent))
5470    }
5471
5472    pub fn indent_guides_in_range<T: ToPoint>(
5473        &self,
5474        range: Range<T>,
5475        ignore_disabled_for_language: bool,
5476        cx: &App,
5477    ) -> impl Iterator<Item = IndentGuide> {
5478        let range = range.start.to_point(self)..range.end.to_point(self);
5479        let start_row = MultiBufferRow(range.start.row);
5480        let end_row = MultiBufferRow(range.end.row);
5481
5482        let mut row_indents = self.line_indents(start_row, |buffer| {
5483            let settings =
5484                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5485            settings.indent_guides.enabled || ignore_disabled_for_language
5486        });
5487
5488        let mut result = Vec::new();
5489        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5490
5491        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5492            if first_row > end_row {
5493                break;
5494            }
5495            let current_depth = indent_stack.len() as u32;
5496
5497            let settings =
5498                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5499            let tab_size = settings.tab_size.get() as u32;
5500
5501            // When encountering empty, continue until found useful line indent
5502            // then add to the indent stack with the depth found
5503            let mut found_indent = false;
5504            let mut last_row = first_row;
5505            if line_indent.is_line_empty() {
5506                while !found_indent {
5507                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5508                        break;
5509                    };
5510                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5511                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5512                        break;
5513                    }
5514
5515                    if new_line_indent.is_line_empty() {
5516                        continue;
5517                    }
5518                    last_row = target_row.min(end_row);
5519                    line_indent = new_line_indent;
5520                    found_indent = true;
5521                    break;
5522                }
5523            } else {
5524                found_indent = true
5525            }
5526
5527            let depth = if found_indent {
5528                line_indent.len(tab_size) / tab_size
5529                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5530            } else {
5531                current_depth
5532            };
5533
5534            match depth.cmp(&current_depth) {
5535                cmp::Ordering::Less => {
5536                    for _ in 0..(current_depth - depth) {
5537                        let mut indent = indent_stack.pop().unwrap();
5538                        if last_row != first_row {
5539                            // In this case, we landed on an empty row, had to seek forward,
5540                            // and discovered that the indent we where on is ending.
5541                            // This means that the last display row must
5542                            // be on line that ends this indent range, so we
5543                            // should display the range up to the first non-empty line
5544                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5545                        }
5546
5547                        result.push(indent)
5548                    }
5549                }
5550                cmp::Ordering::Greater => {
5551                    for next_depth in current_depth..depth {
5552                        indent_stack.push(IndentGuide {
5553                            buffer_id: buffer.remote_id(),
5554                            start_row: first_row,
5555                            end_row: last_row,
5556                            depth: next_depth,
5557                            tab_size,
5558                            settings: settings.indent_guides,
5559                        });
5560                    }
5561                }
5562                _ => {}
5563            }
5564
5565            for indent in indent_stack.iter_mut() {
5566                indent.end_row = last_row;
5567            }
5568        }
5569
5570        result.extend(indent_stack);
5571        result.into_iter()
5572    }
5573
5574    pub fn trailing_excerpt_update_count(&self) -> usize {
5575        self.trailing_excerpt_update_count
5576    }
5577
5578    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5579        self.point_to_buffer_offset(point)
5580            .and_then(|(buffer, _)| buffer.file())
5581    }
5582
5583    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5584        self.point_to_buffer_offset(point)
5585            .and_then(|(buffer, offset)| buffer.language_at(offset))
5586    }
5587
5588    pub fn settings_at<'a, T: ToOffset>(
5589        &'a self,
5590        point: T,
5591        cx: &'a App,
5592    ) -> Cow<'a, LanguageSettings> {
5593        let mut language = None;
5594        let mut file = None;
5595        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5596            language = buffer.language_at(offset);
5597            file = buffer.file();
5598        }
5599        language_settings(language.map(|l| l.name()), file, cx)
5600    }
5601
5602    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5603        self.point_to_buffer_offset(point)
5604            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5605    }
5606
5607    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5608        self.point_to_buffer_offset(point)
5609            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5610            .unwrap_or_default()
5611    }
5612
5613    pub fn language_indent_size_at<T: ToOffset>(
5614        &self,
5615        position: T,
5616        cx: &App,
5617    ) -> Option<IndentSize> {
5618        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5619        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5620    }
5621
5622    pub fn is_dirty(&self) -> bool {
5623        self.is_dirty
5624    }
5625
5626    pub fn has_deleted_file(&self) -> bool {
5627        self.has_deleted_file
5628    }
5629
5630    pub fn has_conflict(&self) -> bool {
5631        self.has_conflict
5632    }
5633
5634    pub fn has_diagnostics(&self) -> bool {
5635        self.excerpts
5636            .iter()
5637            .any(|excerpt| excerpt.buffer.has_diagnostics())
5638    }
5639
5640    pub fn diagnostic_group(
5641        &self,
5642        buffer_id: BufferId,
5643        group_id: usize,
5644    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5645        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5646            if buffer.remote_id() != buffer_id {
5647                return None;
5648            };
5649            Some(
5650                buffer
5651                    .diagnostic_group(group_id)
5652                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5653            )
5654        })
5655        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5656    }
5657
5658    pub fn diagnostics_in_range<'a, T>(
5659        &'a self,
5660        range: Range<T>,
5661    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5662    where
5663        T: 'a
5664            + text::ToOffset
5665            + text::FromAnchor
5666            + TextDimension
5667            + Ord
5668            + Sub<T, Output = T>
5669            + fmt::Debug,
5670    {
5671        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5672            Some(
5673                buffer
5674                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5675                    .map(|entry| (entry.range, entry.diagnostic)),
5676            )
5677        })
5678        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5679    }
5680
5681    pub fn syntax_ancestor<T: ToOffset>(
5682        &self,
5683        range: Range<T>,
5684    ) -> Option<(tree_sitter::Node, Range<usize>)> {
5685        let range = range.start.to_offset(self)..range.end.to_offset(self);
5686        let mut excerpt = self.excerpt_containing(range.clone())?;
5687        let node = excerpt
5688            .buffer()
5689            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5690        Some((node, excerpt.map_range_from_buffer(node.byte_range())))
5691    }
5692
5693    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5694        let (excerpt_id, _, buffer) = self.as_singleton()?;
5695        let outline = buffer.outline(theme)?;
5696        Some(Outline::new(
5697            outline
5698                .items
5699                .into_iter()
5700                .flat_map(|item| {
5701                    Some(OutlineItem {
5702                        depth: item.depth,
5703                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5704                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5705                        text: item.text,
5706                        highlight_ranges: item.highlight_ranges,
5707                        name_ranges: item.name_ranges,
5708                        body_range: item.body_range.and_then(|body_range| {
5709                            Some(
5710                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5711                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5712                            )
5713                        }),
5714                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5715                            Some(
5716                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5717                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5718                            )
5719                        }),
5720                    })
5721                })
5722                .collect(),
5723        ))
5724    }
5725
5726    pub fn symbols_containing<T: ToOffset>(
5727        &self,
5728        offset: T,
5729        theme: Option<&SyntaxTheme>,
5730    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5731        let anchor = self.anchor_before(offset);
5732        let excerpt_id = anchor.excerpt_id;
5733        let excerpt = self.excerpt(excerpt_id)?;
5734        Some((
5735            excerpt.buffer_id,
5736            excerpt
5737                .buffer
5738                .symbols_containing(anchor.text_anchor, theme)
5739                .into_iter()
5740                .flatten()
5741                .flat_map(|item| {
5742                    Some(OutlineItem {
5743                        depth: item.depth,
5744                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5745                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5746                        text: item.text,
5747                        highlight_ranges: item.highlight_ranges,
5748                        name_ranges: item.name_ranges,
5749                        body_range: item.body_range.and_then(|body_range| {
5750                            Some(
5751                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5752                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5753                            )
5754                        }),
5755                        annotation_range: item.annotation_range.and_then(|body_range| {
5756                            Some(
5757                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5758                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5759                            )
5760                        }),
5761                    })
5762                })
5763                .collect(),
5764        ))
5765    }
5766
5767    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5768        if id == ExcerptId::min() {
5769            Locator::min_ref()
5770        } else if id == ExcerptId::max() {
5771            Locator::max_ref()
5772        } else {
5773            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5774            cursor.seek(&id, Bias::Left, &());
5775            if let Some(entry) = cursor.item() {
5776                if entry.id == id {
5777                    return &entry.locator;
5778                }
5779            }
5780            panic!("invalid excerpt id {:?}", id)
5781        }
5782    }
5783
5784    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5785    fn excerpt_locators_for_ids(
5786        &self,
5787        ids: impl IntoIterator<Item = ExcerptId>,
5788    ) -> SmallVec<[Locator; 1]> {
5789        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5790        sorted_ids.sort_unstable();
5791        let mut locators = SmallVec::new();
5792
5793        while sorted_ids.last() == Some(&ExcerptId::max()) {
5794            sorted_ids.pop();
5795            if let Some(mapping) = self.excerpt_ids.last() {
5796                locators.push(mapping.locator.clone());
5797            }
5798        }
5799
5800        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5801        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5802            sorted_ids.next();
5803            if let Some(mapping) = self.excerpt_ids.first() {
5804                locators.push(mapping.locator.clone());
5805            }
5806        }
5807
5808        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5809        for id in sorted_ids {
5810            if cursor.seek_forward(&id, Bias::Left, &()) {
5811                locators.push(cursor.item().unwrap().locator.clone());
5812            } else {
5813                panic!("invalid excerpt id {:?}", id);
5814            }
5815        }
5816
5817        locators.sort_unstable();
5818        locators
5819    }
5820
5821    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5822        Some(self.excerpt(excerpt_id)?.buffer_id)
5823    }
5824
5825    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5826        Some(&self.excerpt(excerpt_id)?.buffer)
5827    }
5828
5829    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5830        let mut cursor = self
5831            .excerpts
5832            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5833        let locator = self.excerpt_locator_for_id(excerpt_id);
5834        if cursor.seek(&Some(locator), Bias::Left, &()) {
5835            let start = cursor.start().1.clone();
5836            let end = cursor.end(&()).1;
5837            let mut diff_transforms = self
5838                .diff_transforms
5839                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5840            diff_transforms.seek(&start, Bias::Left, &());
5841            let overshoot = start.0 - diff_transforms.start().0 .0;
5842            let start = diff_transforms.start().1 .0 + overshoot;
5843            diff_transforms.seek(&end, Bias::Right, &());
5844            let overshoot = end.0 - diff_transforms.start().0 .0;
5845            let end = diff_transforms.start().1 .0 + overshoot;
5846            Some(start..end)
5847        } else {
5848            None
5849        }
5850    }
5851
5852    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5853        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5854        let locator = self.excerpt_locator_for_id(excerpt_id);
5855        if cursor.seek(&Some(locator), Bias::Left, &()) {
5856            if let Some(excerpt) = cursor.item() {
5857                return Some(excerpt.range.context.clone());
5858            }
5859        }
5860        None
5861    }
5862
5863    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5864        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5865        let locator = self.excerpt_locator_for_id(excerpt_id);
5866        cursor.seek(&Some(locator), Bias::Left, &());
5867        if let Some(excerpt) = cursor.item() {
5868            if excerpt.id == excerpt_id {
5869                return Some(excerpt);
5870            }
5871        }
5872        None
5873    }
5874
5875    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5876    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5877        let range = range.start.to_offset(self)..range.end.to_offset(self);
5878        let mut cursor = self.cursor::<usize>();
5879        cursor.seek(&range.start);
5880
5881        let start_excerpt = cursor.excerpt()?;
5882        if range.end != range.start {
5883            cursor.seek_forward(&range.end);
5884            if cursor.excerpt()?.id != start_excerpt.id {
5885                return None;
5886            }
5887        }
5888
5889        cursor.seek_to_start_of_current_excerpt();
5890        let region = cursor.region()?;
5891        let offset = region.range.start;
5892        let buffer_offset = region.buffer_range.start;
5893        let excerpt_offset = cursor.excerpts.start().clone();
5894        Some(MultiBufferExcerpt {
5895            diff_transforms: cursor.diff_transforms,
5896            excerpt: start_excerpt,
5897            offset,
5898            buffer_offset,
5899            excerpt_offset,
5900        })
5901    }
5902
5903    pub fn selections_in_range<'a>(
5904        &'a self,
5905        range: &'a Range<Anchor>,
5906        include_local: bool,
5907    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5908        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5909        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5910        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5911        cursor.seek(start_locator, Bias::Left, &());
5912        cursor
5913            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5914            .flat_map(move |excerpt| {
5915                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5916                if excerpt.id == range.start.excerpt_id {
5917                    query_range.start = range.start.text_anchor;
5918                }
5919                if excerpt.id == range.end.excerpt_id {
5920                    query_range.end = range.end.text_anchor;
5921                }
5922
5923                excerpt
5924                    .buffer
5925                    .selections_in_range(query_range, include_local)
5926                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5927                        selections.map(move |selection| {
5928                            let mut start = Anchor {
5929                                buffer_id: Some(excerpt.buffer_id),
5930                                excerpt_id: excerpt.id,
5931                                text_anchor: selection.start,
5932                                diff_base_anchor: None,
5933                            };
5934                            let mut end = Anchor {
5935                                buffer_id: Some(excerpt.buffer_id),
5936                                excerpt_id: excerpt.id,
5937                                text_anchor: selection.end,
5938                                diff_base_anchor: None,
5939                            };
5940                            if range.start.cmp(&start, self).is_gt() {
5941                                start = range.start;
5942                            }
5943                            if range.end.cmp(&end, self).is_lt() {
5944                                end = range.end;
5945                            }
5946
5947                            (
5948                                replica_id,
5949                                line_mode,
5950                                cursor_shape,
5951                                Selection {
5952                                    id: selection.id,
5953                                    start,
5954                                    end,
5955                                    reversed: selection.reversed,
5956                                    goal: selection.goal,
5957                                },
5958                            )
5959                        })
5960                    })
5961            })
5962    }
5963
5964    pub fn show_headers(&self) -> bool {
5965        self.show_headers
5966    }
5967
5968    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5969        self.diffs.get(&buffer_id)
5970    }
5971}
5972
5973#[cfg(any(test, feature = "test-support"))]
5974impl MultiBufferSnapshot {
5975    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5976        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5977        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5978        start..end
5979    }
5980
5981    #[cfg(any(test, feature = "test-support"))]
5982    fn check_invariants(&self) {
5983        let excerpts = self.excerpts.items(&());
5984        let excerpt_ids = self.excerpt_ids.items(&());
5985
5986        for (ix, excerpt) in excerpts.iter().enumerate() {
5987            if ix == 0 {
5988                if excerpt.locator <= Locator::min() {
5989                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5990                }
5991            } else if excerpt.locator <= excerpts[ix - 1].locator {
5992                panic!("excerpts are out-of-order: {:?}", excerpts);
5993            }
5994        }
5995
5996        for (ix, entry) in excerpt_ids.iter().enumerate() {
5997            if ix == 0 {
5998                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5999                    panic!("invalid first excerpt id {:?}", entry.id);
6000                }
6001            } else if entry.id <= excerpt_ids[ix - 1].id {
6002                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6003            }
6004        }
6005
6006        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6007            panic!(
6008                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6009                self.excerpts.summary().text.len,
6010                self.diff_transforms.summary().input,
6011                self.diff_transforms.items(&()),
6012            );
6013        }
6014
6015        let mut prev_transform: Option<&DiffTransform> = None;
6016        for item in self.diff_transforms.iter() {
6017            if let DiffTransform::BufferContent {
6018                summary,
6019                inserted_hunk_info,
6020            } = item
6021            {
6022                if let Some(DiffTransform::BufferContent {
6023                    inserted_hunk_info: prev_inserted_hunk_info,
6024                    ..
6025                }) = prev_transform
6026                {
6027                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6028                        panic!(
6029                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6030                            self.diff_transforms.items(&()));
6031                    }
6032                }
6033                if summary.len == 0 && !self.is_empty() {
6034                    panic!("empty buffer content transform");
6035                }
6036            }
6037            prev_transform = Some(item);
6038        }
6039    }
6040}
6041
6042impl<'a, D> MultiBufferCursor<'a, D>
6043where
6044    D: TextDimension + Ord + Sub<D, Output = D>,
6045{
6046    fn seek(&mut self, position: &D) {
6047        self.cached_region.take();
6048        self.diff_transforms
6049            .seek(&OutputDimension(*position), Bias::Right, &());
6050        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6051            self.diff_transforms.prev(&());
6052        }
6053
6054        let mut excerpt_position = self.diff_transforms.start().1 .0;
6055        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6056            let overshoot = *position - self.diff_transforms.start().0 .0;
6057            excerpt_position.add_assign(&overshoot);
6058        }
6059
6060        self.excerpts
6061            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6062        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6063            self.excerpts.prev(&());
6064        }
6065    }
6066
6067    fn seek_forward(&mut self, position: &D) {
6068        self.cached_region.take();
6069        self.diff_transforms
6070            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6071        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6072            self.diff_transforms.prev(&());
6073        }
6074
6075        let overshoot = *position - self.diff_transforms.start().0 .0;
6076        let mut excerpt_position = self.diff_transforms.start().1 .0;
6077        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6078            excerpt_position.add_assign(&overshoot);
6079        }
6080
6081        self.excerpts
6082            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6083        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6084            self.excerpts.prev(&());
6085        }
6086    }
6087
6088    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
6089        self.cached_region.take();
6090        if let Some(excerpt) = self.excerpts.item() {
6091            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
6092            let position_in_excerpt = *position - excerpt_start;
6093            let mut excerpt_position = self.excerpts.start().0;
6094            excerpt_position.add_assign(&position_in_excerpt);
6095            self.diff_transforms
6096                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
6097            if self.diff_transforms.item().is_none() {
6098                self.diff_transforms.next(&());
6099            }
6100        }
6101    }
6102
6103    fn next_excerpt(&mut self) {
6104        self.excerpts.next(&());
6105        self.seek_to_start_of_current_excerpt();
6106    }
6107
6108    fn prev_excerpt(&mut self) {
6109        self.excerpts.prev(&());
6110        self.seek_to_start_of_current_excerpt();
6111    }
6112
6113    fn seek_to_start_of_current_excerpt(&mut self) {
6114        self.cached_region.take();
6115        self.diff_transforms
6116            .seek(self.excerpts.start(), Bias::Left, &());
6117        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6118            && self.diff_transforms.start().1 < *self.excerpts.start()
6119            && self.diff_transforms.next_item().is_some()
6120        {
6121            self.diff_transforms.next(&());
6122        }
6123    }
6124
6125    fn next(&mut self) {
6126        self.cached_region.take();
6127        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6128            cmp::Ordering::Less => self.diff_transforms.next(&()),
6129            cmp::Ordering::Greater => self.excerpts.next(&()),
6130            cmp::Ordering::Equal => {
6131                self.diff_transforms.next(&());
6132                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6133                    || self.diff_transforms.item().is_none()
6134                {
6135                    self.excerpts.next(&());
6136                }
6137            }
6138        }
6139    }
6140
6141    fn prev(&mut self) {
6142        self.cached_region.take();
6143        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6144            cmp::Ordering::Less => self.excerpts.prev(&()),
6145            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6146            cmp::Ordering::Equal => {
6147                self.diff_transforms.prev(&());
6148                if self.diff_transforms.start().1 < *self.excerpts.start()
6149                    || self.diff_transforms.item().is_none()
6150                {
6151                    self.excerpts.prev(&());
6152                }
6153            }
6154        }
6155    }
6156
6157    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6158        if self.cached_region.is_none() {
6159            self.cached_region = self.build_region();
6160        }
6161        self.cached_region.clone()
6162    }
6163
6164    fn is_at_end_of_excerpt(&mut self) -> bool {
6165        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6166            return false;
6167        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6168            || self.diff_transforms.item().is_none()
6169        {
6170            return true;
6171        }
6172
6173        self.diff_transforms.next(&());
6174        let next_transform = self.diff_transforms.item();
6175        self.diff_transforms.prev(&());
6176
6177        next_transform.map_or(true, |next_transform| {
6178            matches!(next_transform, DiffTransform::BufferContent { .. })
6179        })
6180    }
6181
6182    fn main_buffer_position(&self) -> Option<D> {
6183        let excerpt = self.excerpts.item()?;
6184        let buffer = &excerpt.buffer;
6185        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6186        let mut buffer_start = buffer_context_start;
6187        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6188        buffer_start.add_assign(&overshoot);
6189        Some(buffer_start)
6190    }
6191
6192    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6193        let excerpt = self.excerpts.item()?;
6194        match self.diff_transforms.item()? {
6195            DiffTransform::DeletedHunk {
6196                buffer_id,
6197                base_text_byte_range,
6198                has_trailing_newline,
6199                hunk_info,
6200                ..
6201            } => {
6202                let diff = self.diffs.get(&buffer_id)?;
6203                let buffer = diff.base_text()?;
6204                let mut rope_cursor = buffer.as_rope().cursor(0);
6205                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6206                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6207                let mut buffer_end = buffer_start;
6208                buffer_end.add_assign(&buffer_range_len);
6209                let start = self.diff_transforms.start().0 .0;
6210                let end = self.diff_transforms.end(&()).0 .0;
6211                return Some(MultiBufferRegion {
6212                    buffer,
6213                    excerpt,
6214                    has_trailing_newline: *has_trailing_newline,
6215                    is_main_buffer: false,
6216                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6217                        hunk_info.hunk_secondary_status,
6218                    )),
6219                    buffer_range: buffer_start..buffer_end,
6220                    range: start..end,
6221                });
6222            }
6223            DiffTransform::BufferContent {
6224                inserted_hunk_info, ..
6225            } => {
6226                let buffer = &excerpt.buffer;
6227                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6228
6229                let mut start = self.diff_transforms.start().0 .0;
6230                let mut buffer_start = buffer_context_start;
6231                if self.diff_transforms.start().1 < *self.excerpts.start() {
6232                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6233                    start.add_assign(&overshoot);
6234                } else {
6235                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6236                    buffer_start.add_assign(&overshoot);
6237                }
6238
6239                let mut end;
6240                let mut buffer_end;
6241                let has_trailing_newline;
6242                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6243                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6244                    end = self.diff_transforms.end(&()).0 .0;
6245                    buffer_end = buffer_context_start;
6246                    buffer_end.add_assign(&overshoot);
6247                    has_trailing_newline = false;
6248                } else {
6249                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6250                    end = self.diff_transforms.start().0 .0;
6251                    end.add_assign(&overshoot);
6252                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6253                    has_trailing_newline = excerpt.has_trailing_newline;
6254                };
6255
6256                Some(MultiBufferRegion {
6257                    buffer,
6258                    excerpt,
6259                    has_trailing_newline,
6260                    is_main_buffer: true,
6261                    diff_hunk_status: inserted_hunk_info
6262                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6263                    buffer_range: buffer_start..buffer_end,
6264                    range: start..end,
6265                })
6266            }
6267        }
6268    }
6269
6270    fn excerpt(&self) -> Option<&'a Excerpt> {
6271        self.excerpts.item()
6272    }
6273}
6274
6275impl History {
6276    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6277        self.transaction_depth += 1;
6278        if self.transaction_depth == 1 {
6279            let id = self.next_transaction_id.tick();
6280            self.undo_stack.push(Transaction {
6281                id,
6282                buffer_transactions: Default::default(),
6283                first_edit_at: now,
6284                last_edit_at: now,
6285                suppress_grouping: false,
6286            });
6287            Some(id)
6288        } else {
6289            None
6290        }
6291    }
6292
6293    fn end_transaction(
6294        &mut self,
6295        now: Instant,
6296        buffer_transactions: HashMap<BufferId, TransactionId>,
6297    ) -> bool {
6298        assert_ne!(self.transaction_depth, 0);
6299        self.transaction_depth -= 1;
6300        if self.transaction_depth == 0 {
6301            if buffer_transactions.is_empty() {
6302                self.undo_stack.pop();
6303                false
6304            } else {
6305                self.redo_stack.clear();
6306                let transaction = self.undo_stack.last_mut().unwrap();
6307                transaction.last_edit_at = now;
6308                for (buffer_id, transaction_id) in buffer_transactions {
6309                    transaction
6310                        .buffer_transactions
6311                        .entry(buffer_id)
6312                        .or_insert(transaction_id);
6313                }
6314                true
6315            }
6316        } else {
6317            false
6318        }
6319    }
6320
6321    fn push_transaction<'a, T>(
6322        &mut self,
6323        buffer_transactions: T,
6324        now: Instant,
6325        cx: &Context<MultiBuffer>,
6326    ) where
6327        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6328    {
6329        assert_eq!(self.transaction_depth, 0);
6330        let transaction = Transaction {
6331            id: self.next_transaction_id.tick(),
6332            buffer_transactions: buffer_transactions
6333                .into_iter()
6334                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6335                .collect(),
6336            first_edit_at: now,
6337            last_edit_at: now,
6338            suppress_grouping: false,
6339        };
6340        if !transaction.buffer_transactions.is_empty() {
6341            self.undo_stack.push(transaction);
6342            self.redo_stack.clear();
6343        }
6344    }
6345
6346    fn finalize_last_transaction(&mut self) {
6347        if let Some(transaction) = self.undo_stack.last_mut() {
6348            transaction.suppress_grouping = true;
6349        }
6350    }
6351
6352    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6353        if let Some(ix) = self
6354            .undo_stack
6355            .iter()
6356            .rposition(|transaction| transaction.id == transaction_id)
6357        {
6358            Some(self.undo_stack.remove(ix))
6359        } else if let Some(ix) = self
6360            .redo_stack
6361            .iter()
6362            .rposition(|transaction| transaction.id == transaction_id)
6363        {
6364            Some(self.redo_stack.remove(ix))
6365        } else {
6366            None
6367        }
6368    }
6369
6370    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6371        self.undo_stack
6372            .iter()
6373            .find(|transaction| transaction.id == transaction_id)
6374            .or_else(|| {
6375                self.redo_stack
6376                    .iter()
6377                    .find(|transaction| transaction.id == transaction_id)
6378            })
6379    }
6380
6381    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6382        self.undo_stack
6383            .iter_mut()
6384            .find(|transaction| transaction.id == transaction_id)
6385            .or_else(|| {
6386                self.redo_stack
6387                    .iter_mut()
6388                    .find(|transaction| transaction.id == transaction_id)
6389            })
6390    }
6391
6392    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6393        assert_eq!(self.transaction_depth, 0);
6394        if let Some(transaction) = self.undo_stack.pop() {
6395            self.redo_stack.push(transaction);
6396            self.redo_stack.last_mut()
6397        } else {
6398            None
6399        }
6400    }
6401
6402    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6403        assert_eq!(self.transaction_depth, 0);
6404        if let Some(transaction) = self.redo_stack.pop() {
6405            self.undo_stack.push(transaction);
6406            self.undo_stack.last_mut()
6407        } else {
6408            None
6409        }
6410    }
6411
6412    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6413        let ix = self
6414            .undo_stack
6415            .iter()
6416            .rposition(|transaction| transaction.id == transaction_id)?;
6417        let transaction = self.undo_stack.remove(ix);
6418        self.redo_stack.push(transaction);
6419        self.redo_stack.last()
6420    }
6421
6422    fn group(&mut self) -> Option<TransactionId> {
6423        let mut count = 0;
6424        let mut transactions = self.undo_stack.iter();
6425        if let Some(mut transaction) = transactions.next_back() {
6426            while let Some(prev_transaction) = transactions.next_back() {
6427                if !prev_transaction.suppress_grouping
6428                    && transaction.first_edit_at - prev_transaction.last_edit_at
6429                        <= self.group_interval
6430                {
6431                    transaction = prev_transaction;
6432                    count += 1;
6433                } else {
6434                    break;
6435                }
6436            }
6437        }
6438        self.group_trailing(count)
6439    }
6440
6441    fn group_until(&mut self, transaction_id: TransactionId) {
6442        let mut count = 0;
6443        for transaction in self.undo_stack.iter().rev() {
6444            if transaction.id == transaction_id {
6445                self.group_trailing(count);
6446                break;
6447            } else if transaction.suppress_grouping {
6448                break;
6449            } else {
6450                count += 1;
6451            }
6452        }
6453    }
6454
6455    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6456        let new_len = self.undo_stack.len() - n;
6457        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6458        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6459            if let Some(transaction) = transactions_to_merge.last() {
6460                last_transaction.last_edit_at = transaction.last_edit_at;
6461            }
6462            for to_merge in transactions_to_merge {
6463                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6464                    last_transaction
6465                        .buffer_transactions
6466                        .entry(*buffer_id)
6467                        .or_insert(*transaction_id);
6468                }
6469            }
6470        }
6471
6472        self.undo_stack.truncate(new_len);
6473        self.undo_stack.last().map(|t| t.id)
6474    }
6475}
6476
6477impl Excerpt {
6478    fn new(
6479        id: ExcerptId,
6480        locator: Locator,
6481        buffer_id: BufferId,
6482        buffer: BufferSnapshot,
6483        range: ExcerptRange<text::Anchor>,
6484        has_trailing_newline: bool,
6485    ) -> Self {
6486        Excerpt {
6487            id,
6488            locator,
6489            max_buffer_row: range.context.end.to_point(&buffer).row,
6490            text_summary: buffer
6491                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6492            buffer_id,
6493            buffer,
6494            range,
6495            has_trailing_newline,
6496        }
6497    }
6498
6499    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6500        let content_start = self.range.context.start.to_offset(&self.buffer);
6501        let chunks_start = content_start + range.start;
6502        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6503
6504        let footer_height = if self.has_trailing_newline
6505            && range.start <= self.text_summary.len
6506            && range.end > self.text_summary.len
6507        {
6508            1
6509        } else {
6510            0
6511        };
6512
6513        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6514
6515        ExcerptChunks {
6516            excerpt_id: self.id,
6517            content_chunks,
6518            footer_height,
6519        }
6520    }
6521
6522    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6523        let content_start = self.range.context.start.to_offset(&self.buffer);
6524        let chunks_start = content_start + range.start;
6525        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6526        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6527        excerpt_chunks.footer_height = if self.has_trailing_newline
6528            && range.start <= self.text_summary.len
6529            && range.end > self.text_summary.len
6530        {
6531            1
6532        } else {
6533            0
6534        };
6535    }
6536
6537    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6538        if text_anchor
6539            .cmp(&self.range.context.start, &self.buffer)
6540            .is_lt()
6541        {
6542            self.range.context.start
6543        } else if text_anchor
6544            .cmp(&self.range.context.end, &self.buffer)
6545            .is_gt()
6546        {
6547            self.range.context.end
6548        } else {
6549            text_anchor
6550        }
6551    }
6552
6553    fn contains(&self, anchor: &Anchor) -> bool {
6554        Some(self.buffer_id) == anchor.buffer_id
6555            && self
6556                .range
6557                .context
6558                .start
6559                .cmp(&anchor.text_anchor, &self.buffer)
6560                .is_le()
6561            && self
6562                .range
6563                .context
6564                .end
6565                .cmp(&anchor.text_anchor, &self.buffer)
6566                .is_ge()
6567    }
6568
6569    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6570    fn buffer_start_offset(&self) -> usize {
6571        self.range.context.start.to_offset(&self.buffer)
6572    }
6573
6574    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6575    fn buffer_end_offset(&self) -> usize {
6576        self.buffer_start_offset() + self.text_summary.len
6577    }
6578}
6579
6580impl<'a> MultiBufferExcerpt<'a> {
6581    pub fn id(&self) -> ExcerptId {
6582        self.excerpt.id
6583    }
6584
6585    pub fn buffer_id(&self) -> BufferId {
6586        self.excerpt.buffer_id
6587    }
6588
6589    pub fn start_anchor(&self) -> Anchor {
6590        Anchor {
6591            buffer_id: Some(self.excerpt.buffer_id),
6592            excerpt_id: self.excerpt.id,
6593            text_anchor: self.excerpt.range.context.start,
6594            diff_base_anchor: None,
6595        }
6596    }
6597
6598    pub fn end_anchor(&self) -> Anchor {
6599        Anchor {
6600            buffer_id: Some(self.excerpt.buffer_id),
6601            excerpt_id: self.excerpt.id,
6602            text_anchor: self.excerpt.range.context.end,
6603            diff_base_anchor: None,
6604        }
6605    }
6606
6607    pub fn buffer(&self) -> &'a BufferSnapshot {
6608        &self.excerpt.buffer
6609    }
6610
6611    pub fn buffer_range(&self) -> Range<usize> {
6612        self.buffer_offset
6613            ..self
6614                .excerpt
6615                .range
6616                .context
6617                .end
6618                .to_offset(&self.excerpt.buffer.text)
6619    }
6620
6621    pub fn start_offset(&self) -> usize {
6622        self.offset
6623    }
6624
6625    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6626    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6627        self.map_range_to_buffer(offset..offset).start
6628    }
6629
6630    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6631    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6632        self.diff_transforms
6633            .seek(&OutputDimension(range.start), Bias::Right, &());
6634        let start = self.map_offset_to_buffer_internal(range.start);
6635        let end = if range.end > range.start {
6636            self.diff_transforms
6637                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6638            self.map_offset_to_buffer_internal(range.end)
6639        } else {
6640            start
6641        };
6642        start..end
6643    }
6644
6645    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6646        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6647        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6648            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6649        };
6650        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6651        self.buffer_offset + offset_in_excerpt
6652    }
6653
6654    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6655    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6656        self.map_range_from_buffer(buffer_offset..buffer_offset)
6657            .start
6658    }
6659
6660    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6661    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6662        let overshoot = buffer_range.start - self.buffer_offset;
6663        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6664        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6665        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6666        let start = self.diff_transforms.start().0 .0 + overshoot;
6667
6668        let end = if buffer_range.end > buffer_range.start {
6669            let overshoot = buffer_range.end - self.buffer_offset;
6670            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6671            self.diff_transforms
6672                .seek_forward(&excerpt_offset, Bias::Right, &());
6673            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6674            self.diff_transforms.start().0 .0 + overshoot
6675        } else {
6676            start
6677        };
6678
6679        start..end
6680    }
6681
6682    /// Returns true if the entirety of the given range is in the buffer's excerpt
6683    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6684        range.start >= self.excerpt.buffer_start_offset()
6685            && range.end <= self.excerpt.buffer_end_offset()
6686    }
6687
6688    pub fn max_buffer_row(&self) -> u32 {
6689        self.excerpt.max_buffer_row
6690    }
6691}
6692
6693impl ExcerptId {
6694    pub fn min() -> Self {
6695        Self(0)
6696    }
6697
6698    pub fn max() -> Self {
6699        Self(usize::MAX)
6700    }
6701
6702    pub fn to_proto(&self) -> u64 {
6703        self.0 as _
6704    }
6705
6706    pub fn from_proto(proto: u64) -> Self {
6707        Self(proto as _)
6708    }
6709
6710    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6711        let a = snapshot.excerpt_locator_for_id(*self);
6712        let b = snapshot.excerpt_locator_for_id(*other);
6713        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6714    }
6715}
6716
6717impl From<ExcerptId> for usize {
6718    fn from(val: ExcerptId) -> Self {
6719        val.0
6720    }
6721}
6722
6723impl fmt::Debug for Excerpt {
6724    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6725        f.debug_struct("Excerpt")
6726            .field("id", &self.id)
6727            .field("locator", &self.locator)
6728            .field("buffer_id", &self.buffer_id)
6729            .field("range", &self.range)
6730            .field("text_summary", &self.text_summary)
6731            .field("has_trailing_newline", &self.has_trailing_newline)
6732            .finish()
6733    }
6734}
6735
6736impl sum_tree::Item for Excerpt {
6737    type Summary = ExcerptSummary;
6738
6739    fn summary(&self, _cx: &()) -> Self::Summary {
6740        let mut text = self.text_summary;
6741        if self.has_trailing_newline {
6742            text += TextSummary::from("\n");
6743        }
6744        ExcerptSummary {
6745            excerpt_id: self.id,
6746            excerpt_locator: self.locator.clone(),
6747            widest_line_number: self.max_buffer_row,
6748            text,
6749        }
6750    }
6751}
6752
6753impl sum_tree::Item for ExcerptIdMapping {
6754    type Summary = ExcerptId;
6755
6756    fn summary(&self, _cx: &()) -> Self::Summary {
6757        self.id
6758    }
6759}
6760
6761impl sum_tree::KeyedItem for ExcerptIdMapping {
6762    type Key = ExcerptId;
6763
6764    fn key(&self) -> Self::Key {
6765        self.id
6766    }
6767}
6768
6769impl DiffTransform {
6770    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6771        match self {
6772            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6773            DiffTransform::BufferContent {
6774                inserted_hunk_info, ..
6775            } => *inserted_hunk_info,
6776        }
6777    }
6778}
6779
6780impl sum_tree::Item for DiffTransform {
6781    type Summary = DiffTransformSummary;
6782
6783    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6784        match self {
6785            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6786                input: *summary,
6787                output: *summary,
6788            },
6789            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6790                input: TextSummary::default(),
6791                output: *summary,
6792            },
6793        }
6794    }
6795}
6796
6797impl DiffTransformSummary {
6798    fn excerpt_len(&self) -> ExcerptOffset {
6799        ExcerptOffset::new(self.input.len)
6800    }
6801}
6802
6803impl sum_tree::Summary for DiffTransformSummary {
6804    type Context = ();
6805
6806    fn zero(_: &Self::Context) -> Self {
6807        DiffTransformSummary {
6808            input: TextSummary::default(),
6809            output: TextSummary::default(),
6810        }
6811    }
6812
6813    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6814        self.input += &summary.input;
6815        self.output += &summary.output;
6816    }
6817}
6818
6819impl sum_tree::Summary for ExcerptId {
6820    type Context = ();
6821
6822    fn zero(_cx: &()) -> Self {
6823        Default::default()
6824    }
6825
6826    fn add_summary(&mut self, other: &Self, _: &()) {
6827        *self = *other;
6828    }
6829}
6830
6831impl sum_tree::Summary for ExcerptSummary {
6832    type Context = ();
6833
6834    fn zero(_cx: &()) -> Self {
6835        Default::default()
6836    }
6837
6838    fn add_summary(&mut self, summary: &Self, _: &()) {
6839        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6840        self.excerpt_locator = summary.excerpt_locator.clone();
6841        self.text.add_summary(&summary.text, &());
6842        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6843    }
6844}
6845
6846impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6847    fn zero(_cx: &()) -> Self {
6848        Default::default()
6849    }
6850
6851    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6852        self.value += summary.text.len;
6853    }
6854}
6855
6856impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6857    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6858        Ord::cmp(&self.value, &cursor_location.text.len)
6859    }
6860}
6861
6862impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6863    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6864        Ord::cmp(&Some(self), cursor_location)
6865    }
6866}
6867
6868impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
6869    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6870        Ord::cmp(self, &cursor_location.excerpt_locator)
6871    }
6872}
6873
6874impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6875    fn zero(_cx: &()) -> Self {
6876        Default::default()
6877    }
6878
6879    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6880        self.value += summary.text.lines;
6881    }
6882}
6883
6884impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6885    for ExcerptDimension<D>
6886{
6887    fn zero(_: &()) -> Self {
6888        ExcerptDimension(D::default())
6889    }
6890
6891    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6892        self.0.add_assign(&D::from_text_summary(&summary.text))
6893    }
6894}
6895
6896impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6897    fn zero(_cx: &()) -> Self {
6898        Default::default()
6899    }
6900
6901    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6902        *self = Some(&summary.excerpt_locator);
6903    }
6904}
6905
6906impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6907    fn zero(_cx: &()) -> Self {
6908        Default::default()
6909    }
6910
6911    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6912        *self = Some(summary.excerpt_id);
6913    }
6914}
6915
6916#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6917struct ExcerptDimension<T>(T);
6918
6919#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6920struct OutputDimension<T>(T);
6921
6922impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6923    fn zero(_: &()) -> Self {
6924        ExcerptOffset::new(0)
6925    }
6926
6927    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6928        self.value += summary.input.len;
6929    }
6930}
6931
6932impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6933    fn zero(_: &()) -> Self {
6934        ExcerptPoint::new(0, 0)
6935    }
6936
6937    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6938        self.value += summary.input.lines;
6939    }
6940}
6941
6942impl<'a, D: TextDimension + Ord>
6943    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransformSummary> for ExcerptDimension<D>
6944{
6945    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6946        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6947    }
6948}
6949
6950impl<'a, D: TextDimension + Ord>
6951    sum_tree::SeekTarget<'a, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6952    for ExcerptDimension<D>
6953{
6954    fn cmp(
6955        &self,
6956        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6957        _: &(),
6958    ) -> cmp::Ordering {
6959        Ord::cmp(&self.0, &cursor_location.1 .0)
6960    }
6961}
6962
6963impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6964    fn zero(_: &()) -> Self {
6965        ExcerptDimension(D::default())
6966    }
6967
6968    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6969        self.0.add_assign(&D::from_text_summary(&summary.input))
6970    }
6971}
6972
6973impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6974    fn zero(_: &()) -> Self {
6975        OutputDimension(D::default())
6976    }
6977
6978    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6979        self.0.add_assign(&D::from_text_summary(&summary.output))
6980    }
6981}
6982
6983impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6984    fn zero(_: &()) -> Self {
6985        TextSummary::default()
6986    }
6987
6988    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6989        *self += summary.output
6990    }
6991}
6992
6993impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6994    fn zero(_: &()) -> Self {
6995        0
6996    }
6997
6998    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6999        *self += summary.output.len
7000    }
7001}
7002
7003impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7004    fn zero(_: &()) -> Self {
7005        Point::new(0, 0)
7006    }
7007
7008    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7009        *self += summary.output.lines
7010    }
7011}
7012
7013impl<'a> MultiBufferRows<'a> {
7014    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7015        self.point = Point::new(row, 0);
7016        self.cursor.seek(&self.point);
7017    }
7018}
7019
7020impl<'a> Iterator for MultiBufferRows<'a> {
7021    type Item = RowInfo;
7022
7023    fn next(&mut self) -> Option<Self::Item> {
7024        if self.is_empty && self.point.row == 0 {
7025            self.point += Point::new(1, 0);
7026            return Some(RowInfo {
7027                buffer_id: None,
7028                buffer_row: Some(0),
7029                multibuffer_row: Some(MultiBufferRow(0)),
7030                diff_status: None,
7031            });
7032        }
7033
7034        let mut region = self.cursor.region()?;
7035        while self.point >= region.range.end {
7036            self.cursor.next();
7037            if let Some(next_region) = self.cursor.region() {
7038                region = next_region;
7039            } else {
7040                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7041                    let multibuffer_row = MultiBufferRow(self.point.row);
7042                    self.point += Point::new(1, 0);
7043                    let last_excerpt = self
7044                        .cursor
7045                        .excerpts
7046                        .item()
7047                        .or(self.cursor.excerpts.prev_item())?;
7048                    let last_row = last_excerpt
7049                        .range
7050                        .context
7051                        .end
7052                        .to_point(&last_excerpt.buffer)
7053                        .row;
7054                    return Some(RowInfo {
7055                        buffer_id: Some(last_excerpt.buffer_id),
7056                        buffer_row: Some(last_row),
7057                        multibuffer_row: Some(multibuffer_row),
7058                        diff_status: None,
7059                    });
7060                } else {
7061                    return None;
7062                }
7063            };
7064        }
7065
7066        let overshoot = self.point - region.range.start;
7067        let buffer_point = region.buffer_range.start + overshoot;
7068        let result = Some(RowInfo {
7069            buffer_id: Some(region.buffer.remote_id()),
7070            buffer_row: Some(buffer_point.row),
7071            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7072            diff_status: region
7073                .diff_hunk_status
7074                .filter(|_| self.point < region.range.end),
7075        });
7076        self.point += Point::new(1, 0);
7077        result
7078    }
7079}
7080
7081impl<'a> MultiBufferChunks<'a> {
7082    pub fn offset(&self) -> usize {
7083        self.range.start
7084    }
7085
7086    pub fn seek(&mut self, range: Range<usize>) {
7087        self.diff_transforms.seek(&range.end, Bias::Right, &());
7088        let mut excerpt_end = self.diff_transforms.start().1;
7089        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7090            let overshoot = range.end - self.diff_transforms.start().0;
7091            excerpt_end.value += overshoot;
7092        }
7093
7094        self.diff_transforms.seek(&range.start, Bias::Right, &());
7095        let mut excerpt_start = self.diff_transforms.start().1;
7096        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7097            let overshoot = range.start - self.diff_transforms.start().0;
7098            excerpt_start.value += overshoot;
7099        }
7100
7101        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7102        self.buffer_chunk.take();
7103        self.range = range;
7104    }
7105
7106    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7107        self.excerpt_offset_range = new_range.clone();
7108        self.excerpts.seek(&new_range.start, Bias::Right, &());
7109        if let Some(excerpt) = self.excerpts.item() {
7110            let excerpt_start = *self.excerpts.start();
7111            if let Some(excerpt_chunks) = self
7112                .excerpt_chunks
7113                .as_mut()
7114                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7115            {
7116                excerpt.seek_chunks(
7117                    excerpt_chunks,
7118                    (self.excerpt_offset_range.start - excerpt_start).value
7119                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7120                );
7121            } else {
7122                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7123                    (self.excerpt_offset_range.start - excerpt_start).value
7124                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7125                    self.language_aware,
7126                ));
7127            }
7128        } else {
7129            self.excerpt_chunks = None;
7130        }
7131    }
7132
7133    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7134        loop {
7135            if self.excerpt_offset_range.is_empty() {
7136                return None;
7137            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7138                self.excerpt_offset_range.start.value += chunk.text.len();
7139                return Some(chunk);
7140            } else {
7141                self.excerpts.next(&());
7142                let excerpt = self.excerpts.item()?;
7143                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7144                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7145                    self.language_aware,
7146                ));
7147            }
7148        }
7149    }
7150}
7151
7152impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7153    type Item = &'a str;
7154
7155    fn next(&mut self) -> Option<Self::Item> {
7156        let mut region = self.cursor.region()?;
7157        if self.offset == region.range.start {
7158            self.cursor.prev();
7159            region = self.cursor.region()?;
7160            let start_overshoot = self.start.saturating_sub(region.range.start);
7161            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7162                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7163            ));
7164        }
7165
7166        if self.offset == region.range.end && region.has_trailing_newline {
7167            self.offset -= 1;
7168            Some("\n")
7169        } else {
7170            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7171            self.offset -= chunk.len();
7172            Some(chunk)
7173        }
7174    }
7175}
7176
7177impl<'a> Iterator for MultiBufferChunks<'a> {
7178    type Item = Chunk<'a>;
7179
7180    fn next(&mut self) -> Option<Chunk<'a>> {
7181        if self.range.start >= self.range.end {
7182            return None;
7183        }
7184        if self.range.start == self.diff_transforms.end(&()).0 {
7185            self.diff_transforms.next(&());
7186        }
7187
7188        let diff_transform_start = self.diff_transforms.start().0;
7189        let diff_transform_end = self.diff_transforms.end(&()).0;
7190        debug_assert!(self.range.start < diff_transform_end);
7191
7192        let diff_transform = self.diff_transforms.item()?;
7193        match diff_transform {
7194            DiffTransform::BufferContent { .. } => {
7195                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7196                    chunk
7197                } else {
7198                    let chunk = self.next_excerpt_chunk().unwrap();
7199                    self.buffer_chunk.insert(chunk)
7200                };
7201
7202                let chunk_end = self.range.start + chunk.text.len();
7203                let diff_transform_end = diff_transform_end.min(self.range.end);
7204
7205                if diff_transform_end < chunk_end {
7206                    let (before, after) =
7207                        chunk.text.split_at(diff_transform_end - self.range.start);
7208                    self.range.start = diff_transform_end;
7209                    chunk.text = after;
7210                    Some(Chunk {
7211                        text: before,
7212                        ..chunk.clone()
7213                    })
7214                } else {
7215                    self.range.start = chunk_end;
7216                    self.buffer_chunk.take()
7217                }
7218            }
7219            DiffTransform::DeletedHunk {
7220                buffer_id,
7221                base_text_byte_range,
7222                has_trailing_newline,
7223                ..
7224            } => {
7225                let base_text_start =
7226                    base_text_byte_range.start + self.range.start - diff_transform_start;
7227                let base_text_end =
7228                    base_text_byte_range.start + self.range.end - diff_transform_start;
7229                let base_text_end = base_text_end.min(base_text_byte_range.end);
7230
7231                let mut chunks = if let Some((_, mut chunks)) = self
7232                    .diff_base_chunks
7233                    .take()
7234                    .filter(|(id, _)| id == buffer_id)
7235                {
7236                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7237                    {
7238                        chunks.seek(base_text_start..base_text_end);
7239                    }
7240                    chunks
7241                } else {
7242                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text()?;
7243                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7244                };
7245
7246                let chunk = if let Some(chunk) = chunks.next() {
7247                    self.range.start += chunk.text.len();
7248                    self.diff_base_chunks = Some((*buffer_id, chunks));
7249                    chunk
7250                } else {
7251                    debug_assert!(has_trailing_newline);
7252                    self.range.start += "\n".len();
7253                    Chunk {
7254                        text: "\n",
7255                        ..Default::default()
7256                    }
7257                };
7258                Some(chunk)
7259            }
7260        }
7261    }
7262}
7263
7264impl<'a> MultiBufferBytes<'a> {
7265    fn consume(&mut self, len: usize) {
7266        self.range.start += len;
7267        self.chunk = &self.chunk[len..];
7268
7269        if !self.range.is_empty() && self.chunk.is_empty() {
7270            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7271                self.chunk = chunk;
7272            } else if self.has_trailing_newline {
7273                self.has_trailing_newline = false;
7274                self.chunk = b"\n";
7275            } else {
7276                self.cursor.next();
7277                if let Some(region) = self.cursor.region() {
7278                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7279                        region.buffer_range.start
7280                            ..(region.buffer_range.start + self.range.end - region.range.start)
7281                                .min(region.buffer_range.end),
7282                    );
7283                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7284                    self.excerpt_bytes = Some(excerpt_bytes);
7285                    self.has_trailing_newline =
7286                        region.has_trailing_newline && self.range.end >= region.range.end;
7287                    if self.chunk.is_empty() && self.has_trailing_newline {
7288                        self.has_trailing_newline = false;
7289                        self.chunk = b"\n";
7290                    }
7291                }
7292            }
7293        }
7294    }
7295}
7296
7297impl<'a> Iterator for MultiBufferBytes<'a> {
7298    type Item = &'a [u8];
7299
7300    fn next(&mut self) -> Option<Self::Item> {
7301        let chunk = self.chunk;
7302        if chunk.is_empty() {
7303            None
7304        } else {
7305            self.consume(chunk.len());
7306            Some(chunk)
7307        }
7308    }
7309}
7310
7311impl<'a> io::Read for MultiBufferBytes<'a> {
7312    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7313        let len = cmp::min(buf.len(), self.chunk.len());
7314        buf[..len].copy_from_slice(&self.chunk[..len]);
7315        if len > 0 {
7316            self.consume(len);
7317        }
7318        Ok(len)
7319    }
7320}
7321
7322impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
7323    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7324        let len = cmp::min(buf.len(), self.chunk.len());
7325        buf[..len].copy_from_slice(&self.chunk[..len]);
7326        buf[..len].reverse();
7327        if len > 0 {
7328            self.range.end -= len;
7329            self.chunk = &self.chunk[..self.chunk.len() - len];
7330            if !self.range.is_empty() && self.chunk.is_empty() {
7331                if let Some(chunk) = self.chunks.next() {
7332                    self.chunk = chunk.as_bytes();
7333                }
7334            }
7335        }
7336        Ok(len)
7337    }
7338}
7339
7340impl<'a> Iterator for ExcerptChunks<'a> {
7341    type Item = Chunk<'a>;
7342
7343    fn next(&mut self) -> Option<Self::Item> {
7344        if let Some(chunk) = self.content_chunks.next() {
7345            return Some(chunk);
7346        }
7347
7348        if self.footer_height > 0 {
7349            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7350            self.footer_height = 0;
7351            return Some(Chunk {
7352                text,
7353                ..Default::default()
7354            });
7355        }
7356
7357        None
7358    }
7359}
7360
7361impl ToOffset for Point {
7362    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7363        snapshot.point_to_offset(*self)
7364    }
7365}
7366
7367impl ToOffset for usize {
7368    #[track_caller]
7369    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7370        assert!(*self <= snapshot.len(), "offset is out of range");
7371        *self
7372    }
7373}
7374
7375impl ToOffset for OffsetUtf16 {
7376    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7377        snapshot.offset_utf16_to_offset(*self)
7378    }
7379}
7380
7381impl ToOffset for PointUtf16 {
7382    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7383        snapshot.point_utf16_to_offset(*self)
7384    }
7385}
7386
7387impl ToOffsetUtf16 for OffsetUtf16 {
7388    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7389        *self
7390    }
7391}
7392
7393impl ToOffsetUtf16 for usize {
7394    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7395        snapshot.offset_to_offset_utf16(*self)
7396    }
7397}
7398
7399impl ToPoint for usize {
7400    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7401        snapshot.offset_to_point(*self)
7402    }
7403}
7404
7405impl ToPoint for Point {
7406    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7407        *self
7408    }
7409}
7410
7411impl ToPointUtf16 for usize {
7412    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7413        snapshot.offset_to_point_utf16(*self)
7414    }
7415}
7416
7417impl ToPointUtf16 for Point {
7418    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7419        snapshot.point_to_point_utf16(*self)
7420    }
7421}
7422
7423impl ToPointUtf16 for PointUtf16 {
7424    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7425        *self
7426    }
7427}
7428
7429impl From<ExcerptId> for EntityId {
7430    fn from(id: ExcerptId) -> Self {
7431        EntityId::from(id.0 as u64)
7432    }
7433}
7434
7435pub fn build_excerpt_ranges<T>(
7436    buffer: &BufferSnapshot,
7437    ranges: &[Range<T>],
7438    context_line_count: u32,
7439) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7440where
7441    T: text::ToPoint,
7442{
7443    let max_point = buffer.max_point();
7444    let mut range_counts = Vec::new();
7445    let mut excerpt_ranges = Vec::new();
7446    let mut range_iter = ranges
7447        .iter()
7448        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7449        .peekable();
7450    while let Some(range) = range_iter.next() {
7451        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7452        let row = (range.end.row + context_line_count).min(max_point.row);
7453        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7454
7455        let mut ranges_in_excerpt = 1;
7456
7457        while let Some(next_range) = range_iter.peek() {
7458            if next_range.start.row <= excerpt_end.row + context_line_count {
7459                let row = (next_range.end.row + context_line_count).min(max_point.row);
7460                excerpt_end = Point::new(row, buffer.line_len(row));
7461
7462                ranges_in_excerpt += 1;
7463                range_iter.next();
7464            } else {
7465                break;
7466            }
7467        }
7468
7469        excerpt_ranges.push(ExcerptRange {
7470            context: excerpt_start..excerpt_end,
7471            primary: Some(range),
7472        });
7473        range_counts.push(ranges_in_excerpt);
7474    }
7475
7476    (excerpt_ranges, range_counts)
7477}