multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  47use text::{
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50    BufferId, Edit, LineIndent, TextSummary,
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    diffs: HashMap<BufferId, DiffState>,
  72    // all_diff_hunks_expanded: bool,
  73    subscriptions: Topic,
  74    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  75    singleton: bool,
  76    history: History,
  77    title: Option<String>,
  78    capability: Capability,
  79}
  80
  81#[derive(Clone, Debug, PartialEq, Eq)]
  82pub enum MultiOrSingleBufferOffsetRange {
  83    Single(Range<usize>),
  84    Multi(Range<usize>),
  85}
  86
  87#[derive(Clone, Debug, PartialEq, Eq)]
  88pub enum Event {
  89    ExcerptsAdded {
  90        buffer: Entity<Buffer>,
  91        predecessor: ExcerptId,
  92        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  93    },
  94    ExcerptsRemoved {
  95        ids: Vec<ExcerptId>,
  96    },
  97    ExcerptsExpanded {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsEdited {
 101        excerpt_ids: Vec<ExcerptId>,
 102        buffer_ids: Vec<BufferId>,
 103    },
 104    DiffHunksToggled,
 105    Edited {
 106        singleton_buffer_edited: bool,
 107        edited_buffer: Option<Entity<Buffer>>,
 108    },
 109    TransactionUndone {
 110        transaction_id: TransactionId,
 111    },
 112    Reloaded,
 113    ReloadNeeded,
 114
 115    LanguageChanged(BufferId),
 116    CapabilityChanged,
 117    Reparsed(BufferId),
 118    Saved,
 119    FileHandleChanged,
 120    Closed,
 121    Discarded,
 122    DirtyChanged,
 123    DiagnosticsUpdated,
 124}
 125
 126/// A diff hunk, representing a range of consequent lines in a multibuffer.
 127#[derive(Debug, Clone, PartialEq, Eq)]
 128pub struct MultiBufferDiffHunk {
 129    /// The row range in the multibuffer where this diff hunk appears.
 130    pub row_range: Range<MultiBufferRow>,
 131    /// The buffer ID that this hunk belongs to.
 132    pub buffer_id: BufferId,
 133    /// The range of the underlying buffer that this hunk corresponds to.
 134    pub buffer_range: Range<text::Anchor>,
 135    /// The excerpt that contains the diff hunk.
 136    pub excerpt_id: ExcerptId,
 137    /// The range within the buffer's diff base that this hunk corresponds to.
 138    pub diff_base_byte_range: Range<usize>,
 139    /// Whether or not this hunk also appears in the 'secondary diff'.
 140    pub secondary_status: DiffHunkSecondaryStatus,
 141}
 142
 143impl MultiBufferDiffHunk {
 144    pub fn status(&self) -> DiffHunkStatus {
 145        let kind = if self.buffer_range.start == self.buffer_range.end {
 146            DiffHunkStatusKind::Deleted
 147        } else if self.diff_base_byte_range.is_empty() {
 148            DiffHunkStatusKind::Added
 149        } else {
 150            DiffHunkStatusKind::Modified
 151        };
 152        DiffHunkStatus {
 153            kind,
 154            secondary: self.secondary_status,
 155        }
 156    }
 157}
 158
 159#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 160pub struct PathKey {
 161    namespace: &'static str,
 162    path: Arc<Path>,
 163}
 164
 165impl PathKey {
 166    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 167        Self { namespace, path }
 168    }
 169
 170    pub fn path(&self) -> &Arc<Path> {
 171        &self.path
 172    }
 173}
 174
 175pub type MultiBufferPoint = Point;
 176type ExcerptOffset = TypedOffset<Excerpt>;
 177type ExcerptPoint = TypedPoint<Excerpt>;
 178
 179#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 180#[serde(transparent)]
 181pub struct MultiBufferRow(pub u32);
 182
 183impl MultiBufferRow {
 184    pub const MIN: Self = Self(0);
 185    pub const MAX: Self = Self(u32::MAX);
 186}
 187
 188impl std::ops::Add<usize> for MultiBufferRow {
 189    type Output = Self;
 190
 191    fn add(self, rhs: usize) -> Self::Output {
 192        MultiBufferRow(self.0 + rhs as u32)
 193    }
 194}
 195
 196#[derive(Clone)]
 197struct History {
 198    next_transaction_id: TransactionId,
 199    undo_stack: Vec<Transaction>,
 200    redo_stack: Vec<Transaction>,
 201    transaction_depth: usize,
 202    group_interval: Duration,
 203}
 204
 205#[derive(Clone)]
 206struct Transaction {
 207    id: TransactionId,
 208    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 209    first_edit_at: Instant,
 210    last_edit_at: Instant,
 211    suppress_grouping: bool,
 212}
 213
 214pub trait ToOffset: 'static + fmt::Debug {
 215    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 216}
 217
 218pub trait ToOffsetUtf16: 'static + fmt::Debug {
 219    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 220}
 221
 222pub trait ToPoint: 'static + fmt::Debug {
 223    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 224}
 225
 226pub trait ToPointUtf16: 'static + fmt::Debug {
 227    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 228}
 229
 230struct BufferState {
 231    buffer: Entity<Buffer>,
 232    last_version: clock::Global,
 233    last_non_text_state_update_count: usize,
 234    excerpts: Vec<Locator>,
 235    _subscriptions: [gpui::Subscription; 2],
 236}
 237
 238struct DiffState {
 239    diff: Entity<BufferDiff>,
 240    _subscription: gpui::Subscription,
 241}
 242
 243impl DiffState {
 244    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 245        DiffState {
 246            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 247                BufferDiffEvent::DiffChanged { changed_range } => {
 248                    if let Some(changed_range) = changed_range.clone() {
 249                        this.buffer_diff_changed(diff, changed_range, cx)
 250                    }
 251                }
 252                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 253                _ => {}
 254            }),
 255            diff,
 256        }
 257    }
 258}
 259
 260/// The contents of a [`MultiBuffer`] at a single point in time.
 261#[derive(Clone, Default)]
 262pub struct MultiBufferSnapshot {
 263    singleton: bool,
 264    excerpts: SumTree<Excerpt>,
 265    excerpt_ids: SumTree<ExcerptIdMapping>,
 266    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 267    diff_transforms: SumTree<DiffTransform>,
 268    trailing_excerpt_update_count: usize,
 269    all_diff_hunks_expanded: bool,
 270    non_text_state_update_count: usize,
 271    edit_count: usize,
 272    is_dirty: bool,
 273    has_deleted_file: bool,
 274    has_conflict: bool,
 275    show_headers: bool,
 276}
 277
 278#[derive(Debug, Clone)]
 279enum DiffTransform {
 280    BufferContent {
 281        summary: TextSummary,
 282        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 283    },
 284    DeletedHunk {
 285        summary: TextSummary,
 286        buffer_id: BufferId,
 287        hunk_info: DiffTransformHunkInfo,
 288        base_text_byte_range: Range<usize>,
 289        has_trailing_newline: bool,
 290    },
 291}
 292
 293#[derive(Clone, Copy, Debug)]
 294struct DiffTransformHunkInfo {
 295    excerpt_id: ExcerptId,
 296    hunk_start_anchor: text::Anchor,
 297    hunk_secondary_status: DiffHunkSecondaryStatus,
 298}
 299
 300impl Eq for DiffTransformHunkInfo {}
 301
 302impl PartialEq for DiffTransformHunkInfo {
 303    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 304        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 305    }
 306}
 307
 308impl std::hash::Hash for DiffTransformHunkInfo {
 309    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 310        self.excerpt_id.hash(state);
 311        self.hunk_start_anchor.hash(state);
 312    }
 313}
 314
 315#[derive(Clone)]
 316pub struct ExcerptInfo {
 317    pub id: ExcerptId,
 318    pub buffer: BufferSnapshot,
 319    pub buffer_id: BufferId,
 320    pub range: ExcerptRange<text::Anchor>,
 321    pub end_row: MultiBufferRow,
 322}
 323
 324impl std::fmt::Debug for ExcerptInfo {
 325    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 326        f.debug_struct(type_name::<Self>())
 327            .field("id", &self.id)
 328            .field("buffer_id", &self.buffer_id)
 329            .field("path", &self.buffer.file().map(|f| f.path()))
 330            .field("range", &self.range)
 331            .finish()
 332    }
 333}
 334
 335/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 336#[derive(Debug)]
 337pub struct ExcerptBoundary {
 338    pub prev: Option<ExcerptInfo>,
 339    pub next: Option<ExcerptInfo>,
 340    /// The row in the `MultiBuffer` where the boundary is located
 341    pub row: MultiBufferRow,
 342}
 343
 344impl ExcerptBoundary {
 345    pub fn starts_new_buffer(&self) -> bool {
 346        match (self.prev.as_ref(), self.next.as_ref()) {
 347            (None, _) => true,
 348            (Some(_), None) => false,
 349            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 350        }
 351    }
 352}
 353
 354#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 355pub struct RowInfo {
 356    pub buffer_id: Option<BufferId>,
 357    pub buffer_row: Option<u32>,
 358    pub multibuffer_row: Option<MultiBufferRow>,
 359    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 360}
 361
 362/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 363#[derive(Clone)]
 364struct Excerpt {
 365    /// The unique identifier for this excerpt
 366    id: ExcerptId,
 367    /// The location of the excerpt in the [`MultiBuffer`]
 368    locator: Locator,
 369    /// The buffer being excerpted
 370    buffer_id: BufferId,
 371    /// A snapshot of the buffer being excerpted
 372    buffer: BufferSnapshot,
 373    /// The range of the buffer to be shown in the excerpt
 374    range: ExcerptRange<text::Anchor>,
 375    /// The last row in the excerpted slice of the buffer
 376    max_buffer_row: BufferRow,
 377    /// A summary of the text in the excerpt
 378    text_summary: TextSummary,
 379    has_trailing_newline: bool,
 380}
 381
 382/// A public view into an `Excerpt` in a [`MultiBuffer`].
 383///
 384/// Contains methods for getting the [`Buffer`] of the excerpt,
 385/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 386#[derive(Clone)]
 387pub struct MultiBufferExcerpt<'a> {
 388    excerpt: &'a Excerpt,
 389    diff_transforms:
 390        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 391    offset: usize,
 392    excerpt_offset: ExcerptDimension<usize>,
 393    buffer_offset: usize,
 394}
 395
 396#[derive(Clone, Debug)]
 397struct ExcerptIdMapping {
 398    id: ExcerptId,
 399    locator: Locator,
 400}
 401
 402/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 403/// These ranges are relative to the buffer itself
 404#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 405pub struct ExcerptRange<T> {
 406    /// The full range of text to be shown in the excerpt.
 407    pub context: Range<T>,
 408    /// The primary range of text to be highlighted in the excerpt.
 409    /// In a multi-buffer search, this would be the text that matched the search
 410    pub primary: Option<Range<T>>,
 411}
 412
 413#[derive(Clone, Debug, Default)]
 414pub struct ExcerptSummary {
 415    excerpt_id: ExcerptId,
 416    /// The location of the last [`Excerpt`] being summarized
 417    excerpt_locator: Locator,
 418    widest_line_number: u32,
 419    text: TextSummary,
 420}
 421
 422#[derive(Debug, Clone)]
 423pub struct DiffTransformSummary {
 424    input: TextSummary,
 425    output: TextSummary,
 426}
 427
 428#[derive(Clone)]
 429pub struct MultiBufferRows<'a> {
 430    point: Point,
 431    is_empty: bool,
 432    cursor: MultiBufferCursor<'a, Point>,
 433}
 434
 435pub struct MultiBufferChunks<'a> {
 436    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 437    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 438    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 439    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 440    buffer_chunk: Option<Chunk<'a>>,
 441    range: Range<usize>,
 442    excerpt_offset_range: Range<ExcerptOffset>,
 443    excerpt_chunks: Option<ExcerptChunks<'a>>,
 444    language_aware: bool,
 445}
 446
 447pub struct ReversedMultiBufferChunks<'a> {
 448    cursor: MultiBufferCursor<'a, usize>,
 449    current_chunks: Option<rope::Chunks<'a>>,
 450    start: usize,
 451    offset: usize,
 452}
 453
 454pub struct MultiBufferBytes<'a> {
 455    range: Range<usize>,
 456    cursor: MultiBufferCursor<'a, usize>,
 457    excerpt_bytes: Option<text::Bytes<'a>>,
 458    has_trailing_newline: bool,
 459    chunk: &'a [u8],
 460}
 461
 462pub struct ReversedMultiBufferBytes<'a> {
 463    range: Range<usize>,
 464    chunks: ReversedMultiBufferChunks<'a>,
 465    chunk: &'a [u8],
 466}
 467
 468#[derive(Clone)]
 469struct MultiBufferCursor<'a, D: TextDimension> {
 470    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 471    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 472    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 473    cached_region: Option<MultiBufferRegion<'a, D>>,
 474}
 475
 476#[derive(Clone)]
 477struct MultiBufferRegion<'a, D: TextDimension> {
 478    buffer: &'a BufferSnapshot,
 479    is_main_buffer: bool,
 480    diff_hunk_status: Option<DiffHunkStatus>,
 481    excerpt: &'a Excerpt,
 482    buffer_range: Range<D>,
 483    range: Range<D>,
 484    has_trailing_newline: bool,
 485}
 486
 487struct ExcerptChunks<'a> {
 488    excerpt_id: ExcerptId,
 489    content_chunks: BufferChunks<'a>,
 490    footer_height: usize,
 491}
 492
 493#[derive(Debug)]
 494struct BufferEdit {
 495    range: Range<usize>,
 496    new_text: Arc<str>,
 497    is_insertion: bool,
 498    original_indent_column: Option<u32>,
 499    excerpt_id: ExcerptId,
 500}
 501
 502#[derive(Clone, Copy, Debug, PartialEq)]
 503enum DiffChangeKind {
 504    BufferEdited,
 505    DiffUpdated { base_changed: bool },
 506    ExpandOrCollapseHunks { expand: bool },
 507}
 508
 509#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 510pub enum ExpandExcerptDirection {
 511    Up,
 512    Down,
 513    UpAndDown,
 514}
 515
 516impl ExpandExcerptDirection {
 517    pub fn should_expand_up(&self) -> bool {
 518        match self {
 519            ExpandExcerptDirection::Up => true,
 520            ExpandExcerptDirection::Down => false,
 521            ExpandExcerptDirection::UpAndDown => true,
 522        }
 523    }
 524
 525    pub fn should_expand_down(&self) -> bool {
 526        match self {
 527            ExpandExcerptDirection::Up => false,
 528            ExpandExcerptDirection::Down => true,
 529            ExpandExcerptDirection::UpAndDown => true,
 530        }
 531    }
 532}
 533
 534#[derive(Clone, Debug, PartialEq)]
 535pub struct IndentGuide {
 536    pub buffer_id: BufferId,
 537    pub start_row: MultiBufferRow,
 538    pub end_row: MultiBufferRow,
 539    pub depth: u32,
 540    pub tab_size: u32,
 541    pub settings: IndentGuideSettings,
 542}
 543
 544impl IndentGuide {
 545    pub fn indent_level(&self) -> u32 {
 546        self.depth * self.tab_size
 547    }
 548}
 549
 550impl MultiBuffer {
 551    pub fn new(capability: Capability) -> Self {
 552        Self {
 553            snapshot: RefCell::new(MultiBufferSnapshot {
 554                show_headers: true,
 555                ..MultiBufferSnapshot::default()
 556            }),
 557            buffers: RefCell::default(),
 558            diffs: HashMap::default(),
 559            subscriptions: Topic::default(),
 560            singleton: false,
 561            capability,
 562            title: None,
 563            buffers_by_path: Default::default(),
 564            history: History {
 565                next_transaction_id: clock::Lamport::default(),
 566                undo_stack: Vec::new(),
 567                redo_stack: Vec::new(),
 568                transaction_depth: 0,
 569                group_interval: Duration::from_millis(300),
 570            },
 571        }
 572    }
 573
 574    pub fn without_headers(capability: Capability) -> Self {
 575        Self {
 576            snapshot: Default::default(),
 577            buffers: Default::default(),
 578            buffers_by_path: Default::default(),
 579            diffs: HashMap::default(),
 580            subscriptions: Default::default(),
 581            singleton: false,
 582            capability,
 583            history: History {
 584                next_transaction_id: Default::default(),
 585                undo_stack: Default::default(),
 586                redo_stack: Default::default(),
 587                transaction_depth: 0,
 588                group_interval: Duration::from_millis(300),
 589            },
 590            title: Default::default(),
 591        }
 592    }
 593
 594    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 595        let mut buffers = HashMap::default();
 596        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 597            buffers.insert(
 598                *buffer_id,
 599                BufferState {
 600                    buffer: buffer_state.buffer.clone(),
 601                    last_version: buffer_state.last_version.clone(),
 602                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 603                    excerpts: buffer_state.excerpts.clone(),
 604                    _subscriptions: [
 605                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 606                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 607                    ],
 608                },
 609            );
 610        }
 611        let mut diff_bases = HashMap::default();
 612        for (buffer_id, diff) in self.diffs.iter() {
 613            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 614        }
 615        Self {
 616            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 617            buffers: RefCell::new(buffers),
 618            buffers_by_path: Default::default(),
 619            diffs: diff_bases,
 620            subscriptions: Default::default(),
 621            singleton: self.singleton,
 622            capability: self.capability,
 623            history: self.history.clone(),
 624            title: self.title.clone(),
 625        }
 626    }
 627
 628    pub fn with_title(mut self, title: String) -> Self {
 629        self.title = Some(title);
 630        self
 631    }
 632
 633    pub fn read_only(&self) -> bool {
 634        self.capability == Capability::ReadOnly
 635    }
 636
 637    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 638        let mut this = Self::new(buffer.read(cx).capability());
 639        this.singleton = true;
 640        this.push_excerpts(
 641            buffer,
 642            [ExcerptRange {
 643                context: text::Anchor::MIN..text::Anchor::MAX,
 644                primary: None,
 645            }],
 646            cx,
 647        );
 648        this.snapshot.borrow_mut().singleton = true;
 649        this
 650    }
 651
 652    /// Returns an up-to-date snapshot of the MultiBuffer.
 653    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 654        self.sync(cx);
 655        self.snapshot.borrow().clone()
 656    }
 657
 658    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 659        self.sync(cx);
 660        self.snapshot.borrow()
 661    }
 662
 663    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 664        if self.singleton {
 665            return Some(
 666                self.buffers
 667                    .borrow()
 668                    .values()
 669                    .next()
 670                    .unwrap()
 671                    .buffer
 672                    .clone(),
 673            );
 674        } else {
 675            None
 676        }
 677    }
 678
 679    pub fn is_singleton(&self) -> bool {
 680        self.singleton
 681    }
 682
 683    pub fn subscribe(&mut self) -> Subscription {
 684        self.subscriptions.subscribe()
 685    }
 686
 687    pub fn is_dirty(&self, cx: &App) -> bool {
 688        self.read(cx).is_dirty()
 689    }
 690
 691    pub fn has_deleted_file(&self, cx: &App) -> bool {
 692        self.read(cx).has_deleted_file()
 693    }
 694
 695    pub fn has_conflict(&self, cx: &App) -> bool {
 696        self.read(cx).has_conflict()
 697    }
 698
 699    // The `is_empty` signature doesn't match what clippy expects
 700    #[allow(clippy::len_without_is_empty)]
 701    pub fn len(&self, cx: &App) -> usize {
 702        self.read(cx).len()
 703    }
 704
 705    pub fn is_empty(&self) -> bool {
 706        self.buffers.borrow().is_empty()
 707    }
 708
 709    pub fn symbols_containing<T: ToOffset>(
 710        &self,
 711        offset: T,
 712        theme: Option<&SyntaxTheme>,
 713        cx: &App,
 714    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 715        self.read(cx).symbols_containing(offset, theme)
 716    }
 717
 718    pub fn edit<I, S, T>(
 719        &self,
 720        edits: I,
 721        autoindent_mode: Option<AutoindentMode>,
 722        cx: &mut Context<Self>,
 723    ) where
 724        I: IntoIterator<Item = (Range<S>, T)>,
 725        S: ToOffset,
 726        T: Into<Arc<str>>,
 727    {
 728        let snapshot = self.read(cx);
 729        let edits = edits
 730            .into_iter()
 731            .map(|(range, new_text)| {
 732                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 733                if range.start > range.end {
 734                    mem::swap(&mut range.start, &mut range.end);
 735                }
 736                (range, new_text.into())
 737            })
 738            .collect::<Vec<_>>();
 739
 740        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 741
 742        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 743        fn edit_internal(
 744            this: &MultiBuffer,
 745            snapshot: Ref<MultiBufferSnapshot>,
 746            edits: Vec<(Range<usize>, Arc<str>)>,
 747            mut autoindent_mode: Option<AutoindentMode>,
 748            cx: &mut Context<MultiBuffer>,
 749        ) {
 750            if this.read_only() || this.buffers.borrow().is_empty() {
 751                return;
 752            }
 753
 754            let original_indent_columns = match &mut autoindent_mode {
 755                Some(AutoindentMode::Block {
 756                    original_indent_columns,
 757                }) => mem::take(original_indent_columns),
 758                _ => Default::default(),
 759            };
 760
 761            let (buffer_edits, edited_excerpt_ids) =
 762                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 763            drop(snapshot);
 764
 765            let mut buffer_ids = Vec::new();
 766            for (buffer_id, mut edits) in buffer_edits {
 767                buffer_ids.push(buffer_id);
 768                edits.sort_by_key(|edit| edit.range.start);
 769                this.buffers.borrow()[&buffer_id]
 770                    .buffer
 771                    .update(cx, |buffer, cx| {
 772                        let mut edits = edits.into_iter().peekable();
 773                        let mut insertions = Vec::new();
 774                        let mut original_indent_columns = Vec::new();
 775                        let mut deletions = Vec::new();
 776                        let empty_str: Arc<str> = Arc::default();
 777                        while let Some(BufferEdit {
 778                            mut range,
 779                            mut new_text,
 780                            mut is_insertion,
 781                            original_indent_column,
 782                            excerpt_id,
 783                        }) = edits.next()
 784                        {
 785                            while let Some(BufferEdit {
 786                                range: next_range,
 787                                is_insertion: next_is_insertion,
 788                                new_text: next_new_text,
 789                                excerpt_id: next_excerpt_id,
 790                                ..
 791                            }) = edits.peek()
 792                            {
 793                                if range.end >= next_range.start {
 794                                    range.end = cmp::max(next_range.end, range.end);
 795                                    is_insertion |= *next_is_insertion;
 796                                    if excerpt_id == *next_excerpt_id {
 797                                        new_text = format!("{new_text}{next_new_text}").into();
 798                                    }
 799                                    edits.next();
 800                                } else {
 801                                    break;
 802                                }
 803                            }
 804
 805                            if is_insertion {
 806                                original_indent_columns.push(original_indent_column);
 807                                insertions.push((
 808                                    buffer.anchor_before(range.start)
 809                                        ..buffer.anchor_before(range.end),
 810                                    new_text.clone(),
 811                                ));
 812                            } else if !range.is_empty() {
 813                                deletions.push((
 814                                    buffer.anchor_before(range.start)
 815                                        ..buffer.anchor_before(range.end),
 816                                    empty_str.clone(),
 817                                ));
 818                            }
 819                        }
 820
 821                        let deletion_autoindent_mode =
 822                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 823                                Some(AutoindentMode::Block {
 824                                    original_indent_columns: Default::default(),
 825                                })
 826                            } else {
 827                                autoindent_mode.clone()
 828                            };
 829                        let insertion_autoindent_mode =
 830                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 831                                Some(AutoindentMode::Block {
 832                                    original_indent_columns,
 833                                })
 834                            } else {
 835                                autoindent_mode.clone()
 836                            };
 837
 838                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 839                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 840                    })
 841            }
 842
 843            cx.emit(Event::ExcerptsEdited {
 844                excerpt_ids: edited_excerpt_ids,
 845                buffer_ids,
 846            });
 847        }
 848    }
 849
 850    fn convert_edits_to_buffer_edits(
 851        &self,
 852        edits: Vec<(Range<usize>, Arc<str>)>,
 853        snapshot: &MultiBufferSnapshot,
 854        original_indent_columns: &[Option<u32>],
 855    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 856        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 857        let mut edited_excerpt_ids = Vec::new();
 858        let mut cursor = snapshot.cursor::<usize>();
 859        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 860            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 861
 862            cursor.seek(&range.start);
 863            let mut start_region = cursor.region().expect("start offset out of bounds");
 864            if !start_region.is_main_buffer {
 865                cursor.next();
 866                if let Some(region) = cursor.region() {
 867                    start_region = region;
 868                } else {
 869                    continue;
 870                }
 871            }
 872
 873            if range.end < start_region.range.start {
 874                continue;
 875            }
 876
 877            if range.end > start_region.range.end {
 878                cursor.seek_forward(&range.end);
 879            }
 880            let mut end_region = cursor.region().expect("end offset out of bounds");
 881            if !end_region.is_main_buffer {
 882                cursor.prev();
 883                if let Some(region) = cursor.region() {
 884                    end_region = region;
 885                } else {
 886                    continue;
 887                }
 888            }
 889
 890            if range.start > end_region.range.end {
 891                continue;
 892            }
 893
 894            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 895            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 896            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 897                .min(start_region.buffer_range.end);
 898            let buffer_end =
 899                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 900
 901            if start_region.excerpt.id == end_region.excerpt.id {
 902                if start_region.is_main_buffer {
 903                    edited_excerpt_ids.push(start_region.excerpt.id);
 904                    buffer_edits
 905                        .entry(start_region.buffer.remote_id())
 906                        .or_default()
 907                        .push(BufferEdit {
 908                            range: buffer_start..buffer_end,
 909                            new_text,
 910                            is_insertion: true,
 911                            original_indent_column,
 912                            excerpt_id: start_region.excerpt.id,
 913                        });
 914                }
 915            } else {
 916                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 917                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 918                if start_region.is_main_buffer {
 919                    edited_excerpt_ids.push(start_region.excerpt.id);
 920                    buffer_edits
 921                        .entry(start_region.buffer.remote_id())
 922                        .or_default()
 923                        .push(BufferEdit {
 924                            range: start_excerpt_range,
 925                            new_text: new_text.clone(),
 926                            is_insertion: true,
 927                            original_indent_column,
 928                            excerpt_id: start_region.excerpt.id,
 929                        });
 930                }
 931                if end_region.is_main_buffer {
 932                    edited_excerpt_ids.push(end_region.excerpt.id);
 933                    buffer_edits
 934                        .entry(end_region.buffer.remote_id())
 935                        .or_default()
 936                        .push(BufferEdit {
 937                            range: end_excerpt_range,
 938                            new_text: new_text.clone(),
 939                            is_insertion: false,
 940                            original_indent_column,
 941                            excerpt_id: end_region.excerpt.id,
 942                        });
 943                }
 944
 945                cursor.seek(&range.start);
 946                cursor.next_excerpt();
 947                while let Some(region) = cursor.region() {
 948                    if region.excerpt.id == end_region.excerpt.id {
 949                        break;
 950                    }
 951                    if region.is_main_buffer {
 952                        edited_excerpt_ids.push(region.excerpt.id);
 953                        buffer_edits
 954                            .entry(region.buffer.remote_id())
 955                            .or_default()
 956                            .push(BufferEdit {
 957                                range: region.buffer_range,
 958                                new_text: new_text.clone(),
 959                                is_insertion: false,
 960                                original_indent_column,
 961                                excerpt_id: region.excerpt.id,
 962                            });
 963                    }
 964                    cursor.next_excerpt();
 965                }
 966            }
 967        }
 968        (buffer_edits, edited_excerpt_ids)
 969    }
 970
 971    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 972    where
 973        I: IntoIterator<Item = Range<S>>,
 974        S: ToOffset,
 975    {
 976        let snapshot = self.read(cx);
 977        let empty = Arc::<str>::from("");
 978        let edits = ranges
 979            .into_iter()
 980            .map(|range| {
 981                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 982                if range.start > range.end {
 983                    mem::swap(&mut range.start, &mut range.end);
 984                }
 985                (range, empty.clone())
 986            })
 987            .collect::<Vec<_>>();
 988
 989        return autoindent_ranges_internal(self, snapshot, edits, cx);
 990
 991        fn autoindent_ranges_internal(
 992            this: &MultiBuffer,
 993            snapshot: Ref<MultiBufferSnapshot>,
 994            edits: Vec<(Range<usize>, Arc<str>)>,
 995            cx: &mut Context<MultiBuffer>,
 996        ) {
 997            if this.read_only() || this.buffers.borrow().is_empty() {
 998                return;
 999            }
1000
1001            let (buffer_edits, edited_excerpt_ids) =
1002                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1003            drop(snapshot);
1004
1005            let mut buffer_ids = Vec::new();
1006            for (buffer_id, mut edits) in buffer_edits {
1007                buffer_ids.push(buffer_id);
1008                edits.sort_unstable_by_key(|edit| edit.range.start);
1009
1010                let mut ranges: Vec<Range<usize>> = Vec::new();
1011                for edit in edits {
1012                    if let Some(last_range) = ranges.last_mut() {
1013                        if edit.range.start <= last_range.end {
1014                            last_range.end = last_range.end.max(edit.range.end);
1015                            continue;
1016                        }
1017                    }
1018                    ranges.push(edit.range);
1019                }
1020
1021                this.buffers.borrow()[&buffer_id]
1022                    .buffer
1023                    .update(cx, |buffer, cx| {
1024                        buffer.autoindent_ranges(ranges, cx);
1025                    })
1026            }
1027
1028            cx.emit(Event::ExcerptsEdited {
1029                excerpt_ids: edited_excerpt_ids,
1030                buffer_ids,
1031            });
1032        }
1033    }
1034
1035    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1036    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1037    // Panics if the given position is invalid.
1038    pub fn insert_empty_line(
1039        &mut self,
1040        position: impl ToPoint,
1041        space_above: bool,
1042        space_below: bool,
1043        cx: &mut Context<Self>,
1044    ) -> Point {
1045        let multibuffer_point = position.to_point(&self.read(cx));
1046        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1047        self.start_transaction(cx);
1048        let empty_line_start = buffer.update(cx, |buffer, cx| {
1049            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1050        });
1051        self.end_transaction(cx);
1052        multibuffer_point + (empty_line_start - buffer_point)
1053    }
1054
1055    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1056        self.start_transaction_at(Instant::now(), cx)
1057    }
1058
1059    pub fn start_transaction_at(
1060        &mut self,
1061        now: Instant,
1062        cx: &mut Context<Self>,
1063    ) -> Option<TransactionId> {
1064        if let Some(buffer) = self.as_singleton() {
1065            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1066        }
1067
1068        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1069            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1070        }
1071        self.history.start_transaction(now)
1072    }
1073
1074    pub fn last_transaction_id(&self) -> Option<TransactionId> {
1075        let last_transaction = self.history.undo_stack.last()?;
1076        return Some(last_transaction.id);
1077    }
1078
1079    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1080        self.end_transaction_at(Instant::now(), cx)
1081    }
1082
1083    pub fn end_transaction_at(
1084        &mut self,
1085        now: Instant,
1086        cx: &mut Context<Self>,
1087    ) -> Option<TransactionId> {
1088        if let Some(buffer) = self.as_singleton() {
1089            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1090        }
1091
1092        let mut buffer_transactions = HashMap::default();
1093        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1094            if let Some(transaction_id) =
1095                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1096            {
1097                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1098            }
1099        }
1100
1101        if self.history.end_transaction(now, buffer_transactions) {
1102            let transaction_id = self.history.group().unwrap();
1103            Some(transaction_id)
1104        } else {
1105            None
1106        }
1107    }
1108
1109    pub fn edited_ranges_for_transaction<D>(
1110        &self,
1111        transaction_id: TransactionId,
1112        cx: &App,
1113    ) -> Vec<Range<D>>
1114    where
1115        D: TextDimension + Ord + Sub<D, Output = D>,
1116    {
1117        let Some(transaction) = self.history.transaction(transaction_id) else {
1118            return Vec::new();
1119        };
1120
1121        let mut ranges = Vec::new();
1122        let snapshot = self.read(cx);
1123        let buffers = self.buffers.borrow();
1124        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1125
1126        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1127            let Some(buffer_state) = buffers.get(buffer_id) else {
1128                continue;
1129            };
1130
1131            let buffer = buffer_state.buffer.read(cx);
1132            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1133                for excerpt_id in &buffer_state.excerpts {
1134                    cursor.seek(excerpt_id, Bias::Left, &());
1135                    if let Some(excerpt) = cursor.item() {
1136                        if excerpt.locator == *excerpt_id {
1137                            let excerpt_buffer_start =
1138                                excerpt.range.context.start.summary::<D>(buffer);
1139                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1140                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1141                            if excerpt_range.contains(&range.start)
1142                                && excerpt_range.contains(&range.end)
1143                            {
1144                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1145
1146                                let mut start = excerpt_start;
1147                                start.add_assign(&(range.start - excerpt_buffer_start));
1148                                let mut end = excerpt_start;
1149                                end.add_assign(&(range.end - excerpt_buffer_start));
1150
1151                                ranges.push(start..end);
1152                                break;
1153                            }
1154                        }
1155                    }
1156                }
1157            }
1158        }
1159
1160        ranges.sort_by_key(|range| range.start);
1161        ranges
1162    }
1163
1164    pub fn merge_transactions(
1165        &mut self,
1166        transaction: TransactionId,
1167        destination: TransactionId,
1168        cx: &mut Context<Self>,
1169    ) {
1170        if let Some(buffer) = self.as_singleton() {
1171            buffer.update(cx, |buffer, _| {
1172                buffer.merge_transactions(transaction, destination)
1173            });
1174        } else if let Some(transaction) = self.history.forget(transaction) {
1175            if let Some(destination) = self.history.transaction_mut(destination) {
1176                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1177                    if let Some(destination_buffer_transaction_id) =
1178                        destination.buffer_transactions.get(&buffer_id)
1179                    {
1180                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1181                            state.buffer.update(cx, |buffer, _| {
1182                                buffer.merge_transactions(
1183                                    buffer_transaction_id,
1184                                    *destination_buffer_transaction_id,
1185                                )
1186                            });
1187                        }
1188                    } else {
1189                        destination
1190                            .buffer_transactions
1191                            .insert(buffer_id, buffer_transaction_id);
1192                    }
1193                }
1194            }
1195        }
1196    }
1197
1198    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1199        self.history.finalize_last_transaction();
1200        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1201            buffer.update(cx, |buffer, _| {
1202                buffer.finalize_last_transaction();
1203            });
1204        }
1205    }
1206
1207    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1208    where
1209        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1210    {
1211        self.history
1212            .push_transaction(buffer_transactions, Instant::now(), cx);
1213        self.history.finalize_last_transaction();
1214    }
1215
1216    pub fn group_until_transaction(
1217        &mut self,
1218        transaction_id: TransactionId,
1219        cx: &mut Context<Self>,
1220    ) {
1221        if let Some(buffer) = self.as_singleton() {
1222            buffer.update(cx, |buffer, _| {
1223                buffer.group_until_transaction(transaction_id)
1224            });
1225        } else {
1226            self.history.group_until(transaction_id);
1227        }
1228    }
1229
1230    pub fn set_active_selections(
1231        &self,
1232        selections: &[Selection<Anchor>],
1233        line_mode: bool,
1234        cursor_shape: CursorShape,
1235        cx: &mut Context<Self>,
1236    ) {
1237        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1238            Default::default();
1239        let snapshot = self.read(cx);
1240        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1241        for selection in selections {
1242            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1243            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1244
1245            cursor.seek(&Some(start_locator), Bias::Left, &());
1246            while let Some(excerpt) = cursor.item() {
1247                if excerpt.locator > *end_locator {
1248                    break;
1249                }
1250
1251                let mut start = excerpt.range.context.start;
1252                let mut end = excerpt.range.context.end;
1253                if excerpt.id == selection.start.excerpt_id {
1254                    start = selection.start.text_anchor;
1255                }
1256                if excerpt.id == selection.end.excerpt_id {
1257                    end = selection.end.text_anchor;
1258                }
1259                selections_by_buffer
1260                    .entry(excerpt.buffer_id)
1261                    .or_default()
1262                    .push(Selection {
1263                        id: selection.id,
1264                        start,
1265                        end,
1266                        reversed: selection.reversed,
1267                        goal: selection.goal,
1268                    });
1269
1270                cursor.next(&());
1271            }
1272        }
1273
1274        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1275            if !selections_by_buffer.contains_key(buffer_id) {
1276                buffer_state
1277                    .buffer
1278                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1279            }
1280        }
1281
1282        for (buffer_id, mut selections) in selections_by_buffer {
1283            self.buffers.borrow()[&buffer_id]
1284                .buffer
1285                .update(cx, |buffer, cx| {
1286                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1287                    let mut selections = selections.into_iter().peekable();
1288                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1289                        let mut selection = selections.next()?;
1290                        while let Some(next_selection) = selections.peek() {
1291                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1292                                let next_selection = selections.next().unwrap();
1293                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1294                                    selection.end = next_selection.end;
1295                                }
1296                            } else {
1297                                break;
1298                            }
1299                        }
1300                        Some(selection)
1301                    }));
1302                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1303                });
1304        }
1305    }
1306
1307    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1308        for buffer in self.buffers.borrow().values() {
1309            buffer
1310                .buffer
1311                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1312        }
1313    }
1314
1315    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1316        let mut transaction_id = None;
1317        if let Some(buffer) = self.as_singleton() {
1318            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1319        } else {
1320            while let Some(transaction) = self.history.pop_undo() {
1321                let mut undone = false;
1322                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1323                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1324                        undone |= buffer.update(cx, |buffer, cx| {
1325                            let undo_to = *buffer_transaction_id;
1326                            if let Some(entry) = buffer.peek_undo_stack() {
1327                                *buffer_transaction_id = entry.transaction_id();
1328                            }
1329                            buffer.undo_to_transaction(undo_to, cx)
1330                        });
1331                    }
1332                }
1333
1334                if undone {
1335                    transaction_id = Some(transaction.id);
1336                    break;
1337                }
1338            }
1339        }
1340
1341        if let Some(transaction_id) = transaction_id {
1342            cx.emit(Event::TransactionUndone { transaction_id });
1343        }
1344
1345        transaction_id
1346    }
1347
1348    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1349        if let Some(buffer) = self.as_singleton() {
1350            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1351        }
1352
1353        while let Some(transaction) = self.history.pop_redo() {
1354            let mut redone = false;
1355            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1356                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1357                    redone |= buffer.update(cx, |buffer, cx| {
1358                        let redo_to = *buffer_transaction_id;
1359                        if let Some(entry) = buffer.peek_redo_stack() {
1360                            *buffer_transaction_id = entry.transaction_id();
1361                        }
1362                        buffer.redo_to_transaction(redo_to, cx)
1363                    });
1364                }
1365            }
1366
1367            if redone {
1368                return Some(transaction.id);
1369            }
1370        }
1371
1372        None
1373    }
1374
1375    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1376        if let Some(buffer) = self.as_singleton() {
1377            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1378        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1379            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1380                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1381                    buffer.update(cx, |buffer, cx| {
1382                        buffer.undo_transaction(*transaction_id, cx)
1383                    });
1384                }
1385            }
1386        }
1387    }
1388
1389    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1390        if let Some(buffer) = self.as_singleton() {
1391            buffer.update(cx, |buffer, _| {
1392                buffer.forget_transaction(transaction_id);
1393            });
1394        } else if let Some(transaction) = self.history.forget(transaction_id) {
1395            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1396                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1397                    state.buffer.update(cx, |buffer, _| {
1398                        buffer.forget_transaction(buffer_transaction_id);
1399                    });
1400                }
1401            }
1402        }
1403    }
1404
1405    pub fn push_excerpts<O>(
1406        &mut self,
1407        buffer: Entity<Buffer>,
1408        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1409        cx: &mut Context<Self>,
1410    ) -> Vec<ExcerptId>
1411    where
1412        O: text::ToOffset,
1413    {
1414        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1415    }
1416
1417    pub fn push_excerpts_with_context_lines<O>(
1418        &mut self,
1419        buffer: Entity<Buffer>,
1420        ranges: Vec<Range<O>>,
1421        context_line_count: u32,
1422        cx: &mut Context<Self>,
1423    ) -> Vec<Range<Anchor>>
1424    where
1425        O: text::ToPoint + text::ToOffset,
1426    {
1427        let buffer_id = buffer.read(cx).remote_id();
1428        let buffer_snapshot = buffer.read(cx).snapshot();
1429        let (excerpt_ranges, range_counts) =
1430            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1431
1432        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1433
1434        let mut anchor_ranges = Vec::new();
1435        let mut ranges = ranges.into_iter();
1436        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1437            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1438                let start = Anchor {
1439                    buffer_id: Some(buffer_id),
1440                    excerpt_id,
1441                    text_anchor: buffer_snapshot.anchor_after(range.start),
1442                    diff_base_anchor: None,
1443                };
1444                let end = Anchor {
1445                    buffer_id: Some(buffer_id),
1446                    excerpt_id,
1447                    text_anchor: buffer_snapshot.anchor_after(range.end),
1448                    diff_base_anchor: None,
1449                };
1450                start..end
1451            }))
1452        }
1453        anchor_ranges
1454    }
1455
1456    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1457        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1458        let snapshot = self.snapshot(cx);
1459        let excerpt = snapshot.excerpt(*excerpt_id)?;
1460        Some(Anchor::in_buffer(
1461            *excerpt_id,
1462            excerpt.buffer_id,
1463            excerpt.range.context.start,
1464        ))
1465    }
1466
1467    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1468        self.buffers_by_path.keys()
1469    }
1470
1471    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1472    pub fn set_excerpts_for_path(
1473        &mut self,
1474        path: PathKey,
1475        buffer: Entity<Buffer>,
1476        ranges: Vec<Range<Point>>,
1477        context_line_count: u32,
1478        cx: &mut Context<Self>,
1479    ) -> bool {
1480        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1481
1482        let mut insert_after = self
1483            .buffers_by_path
1484            .range(..path.clone())
1485            .next_back()
1486            .map(|(_, value)| *value.last().unwrap())
1487            .unwrap_or(ExcerptId::min());
1488        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1489
1490        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1491
1492        let mut new_iter = new.into_iter().peekable();
1493        let mut existing_iter = existing.into_iter().peekable();
1494
1495        let mut new_excerpt_ids = Vec::new();
1496        let mut to_remove = Vec::new();
1497        let mut to_insert = Vec::new();
1498        let mut added_a_new_excerpt = false;
1499        let snapshot = self.snapshot(cx);
1500
1501        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1502        excerpts_cursor.next(&());
1503
1504        loop {
1505            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1506                (Some(new), Some(existing)) => (new, existing),
1507                (None, None) => break,
1508                (None, Some(_)) => {
1509                    to_remove.push(existing_iter.next().unwrap());
1510                    continue;
1511                }
1512                (Some(_), None) => {
1513                    added_a_new_excerpt = true;
1514                    to_insert.push(new_iter.next().unwrap());
1515                    continue;
1516                }
1517            };
1518            let locator = snapshot.excerpt_locator_for_id(*existing);
1519            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1520            let existing_excerpt = excerpts_cursor.item().unwrap();
1521            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1522                to_remove.push(existing_iter.next().unwrap());
1523                to_insert.push(new_iter.next().unwrap());
1524                continue;
1525            }
1526
1527            let existing_start = existing_excerpt
1528                .range
1529                .context
1530                .start
1531                .to_point(&buffer_snapshot);
1532            let existing_end = existing_excerpt
1533                .range
1534                .context
1535                .end
1536                .to_point(&buffer_snapshot);
1537
1538            if existing_end < new.context.start {
1539                to_remove.push(existing_iter.next().unwrap());
1540                continue;
1541            } else if existing_start > new.context.end {
1542                to_insert.push(new_iter.next().unwrap());
1543                continue;
1544            }
1545
1546            // maybe merge overlapping excerpts?
1547            // it's hard to distinguish between a manually expanded excerpt, and one that
1548            // got smaller because of a missing diff.
1549            if existing_start == new.context.start && existing_end == new.context.end {
1550                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1551                    insert_after,
1552                    buffer.clone(),
1553                    mem::take(&mut to_insert),
1554                    cx,
1555                ));
1556                insert_after = existing_iter.next().unwrap();
1557                new_excerpt_ids.push(insert_after);
1558                new_iter.next();
1559            } else {
1560                to_remove.push(existing_iter.next().unwrap());
1561                to_insert.push(new_iter.next().unwrap());
1562            }
1563        }
1564
1565        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1566            insert_after,
1567            buffer,
1568            to_insert,
1569            cx,
1570        ));
1571        self.remove_excerpts(to_remove, cx);
1572        if new_excerpt_ids.is_empty() {
1573            self.buffers_by_path.remove(&path);
1574        } else {
1575            self.buffers_by_path.insert(path, new_excerpt_ids);
1576        }
1577
1578        added_a_new_excerpt
1579    }
1580
1581    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1582        self.buffers_by_path.keys().cloned()
1583    }
1584
1585    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1586        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1587            self.remove_excerpts(to_remove, cx)
1588        }
1589    }
1590
1591    pub fn push_multiple_excerpts_with_context_lines(
1592        &self,
1593        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1594        context_line_count: u32,
1595        cx: &mut Context<Self>,
1596    ) -> Task<Vec<Range<Anchor>>> {
1597        use futures::StreamExt;
1598
1599        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1600
1601        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1602
1603        for (buffer, ranges) in buffers_with_ranges {
1604            let (buffer_id, buffer_snapshot) =
1605                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1606
1607            buffer_ids.push(buffer_id);
1608
1609            cx.background_spawn({
1610                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1611
1612                async move {
1613                    let (excerpt_ranges, counts) =
1614                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1615                    excerpt_ranges_tx
1616                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1617                        .await
1618                        .ok();
1619                }
1620            })
1621            .detach()
1622        }
1623
1624        cx.spawn(move |this, mut cx| async move {
1625            let mut results_by_buffer_id = HashMap::default();
1626            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1627                excerpt_ranges_rx.next().await
1628            {
1629                results_by_buffer_id
1630                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1631            }
1632
1633            let mut multi_buffer_ranges = Vec::default();
1634            'outer: for buffer_id in buffer_ids {
1635                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1636                    results_by_buffer_id.remove(&buffer_id)
1637                else {
1638                    continue;
1639                };
1640
1641                let mut ranges = ranges.into_iter();
1642                let mut range_counts = range_counts.into_iter();
1643                for excerpt_ranges in excerpt_ranges.chunks(100) {
1644                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1645                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1646                    }) {
1647                        Ok(excerpt_ids) => excerpt_ids,
1648                        Err(_) => continue 'outer,
1649                    };
1650
1651                    for (excerpt_id, range_count) in
1652                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1653                    {
1654                        for range in ranges.by_ref().take(range_count) {
1655                            let start = Anchor {
1656                                buffer_id: Some(buffer_id),
1657                                excerpt_id,
1658                                text_anchor: range.start,
1659                                diff_base_anchor: None,
1660                            };
1661                            let end = Anchor {
1662                                buffer_id: Some(buffer_id),
1663                                excerpt_id,
1664                                text_anchor: range.end,
1665                                diff_base_anchor: None,
1666                            };
1667                            multi_buffer_ranges.push(start..end);
1668                        }
1669                    }
1670                }
1671            }
1672
1673            multi_buffer_ranges
1674        })
1675    }
1676
1677    pub fn insert_excerpts_after<O>(
1678        &mut self,
1679        prev_excerpt_id: ExcerptId,
1680        buffer: Entity<Buffer>,
1681        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1682        cx: &mut Context<Self>,
1683    ) -> Vec<ExcerptId>
1684    where
1685        O: text::ToOffset,
1686    {
1687        let mut ids = Vec::new();
1688        let mut next_excerpt_id =
1689            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1690                last_entry.id.0 + 1
1691            } else {
1692                1
1693            };
1694        self.insert_excerpts_with_ids_after(
1695            prev_excerpt_id,
1696            buffer,
1697            ranges.into_iter().map(|range| {
1698                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1699                ids.push(id);
1700                (id, range)
1701            }),
1702            cx,
1703        );
1704        ids
1705    }
1706
1707    pub fn insert_excerpts_with_ids_after<O>(
1708        &mut self,
1709        prev_excerpt_id: ExcerptId,
1710        buffer: Entity<Buffer>,
1711        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1712        cx: &mut Context<Self>,
1713    ) where
1714        O: text::ToOffset,
1715    {
1716        assert_eq!(self.history.transaction_depth, 0);
1717        let mut ranges = ranges.into_iter().peekable();
1718        if ranges.peek().is_none() {
1719            return Default::default();
1720        }
1721
1722        self.sync(cx);
1723
1724        let buffer_id = buffer.read(cx).remote_id();
1725        let buffer_snapshot = buffer.read(cx).snapshot();
1726
1727        let mut buffers = self.buffers.borrow_mut();
1728        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1729            last_version: buffer_snapshot.version().clone(),
1730            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1731            excerpts: Default::default(),
1732            _subscriptions: [
1733                cx.observe(&buffer, |_, _, cx| cx.notify()),
1734                cx.subscribe(&buffer, Self::on_buffer_event),
1735            ],
1736            buffer: buffer.clone(),
1737        });
1738
1739        let mut snapshot = self.snapshot.borrow_mut();
1740
1741        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1742        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1743        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1744        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1745        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1746
1747        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1748        new_excerpts.update_last(
1749            |excerpt| {
1750                excerpt.has_trailing_newline = true;
1751            },
1752            &(),
1753        );
1754
1755        let next_locator = if let Some(excerpt) = cursor.item() {
1756            excerpt.locator.clone()
1757        } else {
1758            Locator::max()
1759        };
1760
1761        let mut excerpts = Vec::new();
1762        while let Some((id, range)) = ranges.next() {
1763            let locator = Locator::between(&prev_locator, &next_locator);
1764            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1765                buffer_state.excerpts.insert(ix, locator.clone());
1766            }
1767            let range = ExcerptRange {
1768                context: buffer_snapshot.anchor_before(&range.context.start)
1769                    ..buffer_snapshot.anchor_after(&range.context.end),
1770                primary: range.primary.map(|primary| {
1771                    buffer_snapshot.anchor_before(&primary.start)
1772                        ..buffer_snapshot.anchor_after(&primary.end)
1773                }),
1774            };
1775            excerpts.push((id, range.clone()));
1776            let excerpt = Excerpt::new(
1777                id,
1778                locator.clone(),
1779                buffer_id,
1780                buffer_snapshot.clone(),
1781                range,
1782                ranges.peek().is_some() || cursor.item().is_some(),
1783            );
1784            new_excerpts.push(excerpt, &());
1785            prev_locator = locator.clone();
1786
1787            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1788                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1789            }
1790            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1791        }
1792
1793        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1794
1795        let suffix = cursor.suffix(&());
1796        let changed_trailing_excerpt = suffix.is_empty();
1797        new_excerpts.append(suffix, &());
1798        drop(cursor);
1799        snapshot.excerpts = new_excerpts;
1800        snapshot.excerpt_ids = new_excerpt_ids;
1801        if changed_trailing_excerpt {
1802            snapshot.trailing_excerpt_update_count += 1;
1803        }
1804
1805        self.sync_diff_transforms(
1806            &mut snapshot,
1807            vec![Edit {
1808                old: edit_start..edit_start,
1809                new: edit_start..edit_end,
1810            }],
1811            DiffChangeKind::BufferEdited,
1812        );
1813        cx.emit(Event::Edited {
1814            singleton_buffer_edited: false,
1815            edited_buffer: None,
1816        });
1817        cx.emit(Event::ExcerptsAdded {
1818            buffer,
1819            predecessor: prev_excerpt_id,
1820            excerpts,
1821        });
1822        cx.notify();
1823    }
1824
1825    pub fn clear(&mut self, cx: &mut Context<Self>) {
1826        self.sync(cx);
1827        let ids = self.excerpt_ids();
1828        self.buffers.borrow_mut().clear();
1829        let mut snapshot = self.snapshot.borrow_mut();
1830        let start = ExcerptOffset::new(0);
1831        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1832        snapshot.excerpts = Default::default();
1833        snapshot.trailing_excerpt_update_count += 1;
1834        snapshot.is_dirty = false;
1835        snapshot.has_deleted_file = false;
1836        snapshot.has_conflict = false;
1837
1838        self.sync_diff_transforms(
1839            &mut snapshot,
1840            vec![Edit {
1841                old: start..prev_len,
1842                new: start..start,
1843            }],
1844            DiffChangeKind::BufferEdited,
1845        );
1846        cx.emit(Event::Edited {
1847            singleton_buffer_edited: false,
1848            edited_buffer: None,
1849        });
1850        cx.emit(Event::ExcerptsRemoved { ids });
1851        cx.notify();
1852    }
1853
1854    pub fn excerpts_for_buffer(
1855        &self,
1856        buffer_id: BufferId,
1857        cx: &App,
1858    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1859        let mut excerpts = Vec::new();
1860        let snapshot = self.read(cx);
1861        let buffers = self.buffers.borrow();
1862        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1863        for locator in buffers
1864            .get(&buffer_id)
1865            .map(|state| &state.excerpts)
1866            .into_iter()
1867            .flatten()
1868        {
1869            cursor.seek_forward(&Some(locator), Bias::Left, &());
1870            if let Some(excerpt) = cursor.item() {
1871                if excerpt.locator == *locator {
1872                    excerpts.push((excerpt.id, excerpt.range.clone()));
1873                }
1874            }
1875        }
1876
1877        excerpts
1878    }
1879
1880    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1881        let snapshot = self.read(cx);
1882        let buffers = self.buffers.borrow();
1883        let mut excerpts = snapshot
1884            .excerpts
1885            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1886        let mut diff_transforms = snapshot
1887            .diff_transforms
1888            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1889        diff_transforms.next(&());
1890        let locators = buffers
1891            .get(&buffer_id)
1892            .into_iter()
1893            .flat_map(|state| &state.excerpts);
1894        let mut result = Vec::new();
1895        for locator in locators {
1896            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1897            if let Some(excerpt) = excerpts.item() {
1898                if excerpt.locator == *locator {
1899                    let excerpt_start = excerpts.start().1.clone();
1900                    let excerpt_end =
1901                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1902
1903                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1904                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1905                    let start = diff_transforms.start().1 .0 + overshoot;
1906
1907                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1908                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1909                    let end = diff_transforms.start().1 .0 + overshoot;
1910
1911                    result.push(start..end)
1912                }
1913            }
1914        }
1915        result
1916    }
1917
1918    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1919        self.snapshot
1920            .borrow()
1921            .excerpts
1922            .iter()
1923            .map(|entry| entry.buffer_id)
1924            .collect()
1925    }
1926
1927    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1928        self.snapshot
1929            .borrow()
1930            .excerpts
1931            .iter()
1932            .map(|entry| entry.id)
1933            .collect()
1934    }
1935
1936    pub fn excerpt_containing(
1937        &self,
1938        position: impl ToOffset,
1939        cx: &App,
1940    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1941        let snapshot = self.read(cx);
1942        let offset = position.to_offset(&snapshot);
1943
1944        let mut cursor = snapshot.cursor::<usize>();
1945        cursor.seek(&offset);
1946        cursor
1947            .excerpt()
1948            .or_else(|| snapshot.excerpts.last())
1949            .map(|excerpt| {
1950                (
1951                    excerpt.id,
1952                    self.buffers
1953                        .borrow()
1954                        .get(&excerpt.buffer_id)
1955                        .unwrap()
1956                        .buffer
1957                        .clone(),
1958                    excerpt.range.context.clone(),
1959                )
1960            })
1961    }
1962
1963    // If point is at the end of the buffer, the last excerpt is returned
1964    pub fn point_to_buffer_offset<T: ToOffset>(
1965        &self,
1966        point: T,
1967        cx: &App,
1968    ) -> Option<(Entity<Buffer>, usize)> {
1969        let snapshot = self.read(cx);
1970        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1971        Some((
1972            self.buffers
1973                .borrow()
1974                .get(&buffer.remote_id())?
1975                .buffer
1976                .clone(),
1977            offset,
1978        ))
1979    }
1980
1981    // If point is at the end of the buffer, the last excerpt is returned
1982    pub fn point_to_buffer_point<T: ToPoint>(
1983        &self,
1984        point: T,
1985        cx: &App,
1986    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1987        let snapshot = self.read(cx);
1988        let point = point.to_point(&snapshot);
1989        let mut cursor = snapshot.cursor::<Point>();
1990        cursor.seek(&point);
1991
1992        cursor.region().and_then(|region| {
1993            if !region.is_main_buffer {
1994                return None;
1995            }
1996
1997            let overshoot = point - region.range.start;
1998            let buffer_point = region.buffer_range.start + overshoot;
1999            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
2000                .buffer
2001                .clone();
2002            Some((buffer, buffer_point, region.excerpt.id))
2003        })
2004    }
2005
2006    pub fn buffer_point_to_anchor(
2007        &self,
2008        buffer: &Entity<Buffer>,
2009        point: Point,
2010        cx: &App,
2011    ) -> Option<Anchor> {
2012        let mut found = None;
2013        let snapshot = buffer.read(cx).snapshot();
2014        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2015            let start = range.context.start.to_point(&snapshot);
2016            let end = range.context.end.to_point(&snapshot);
2017            if start <= point && point < end {
2018                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2019                break;
2020            }
2021            if point < start {
2022                found = Some((start, excerpt_id));
2023            }
2024            if point > end {
2025                found = Some((end, excerpt_id));
2026            }
2027        }
2028
2029        found.map(|(point, excerpt_id)| {
2030            let text_anchor = snapshot.anchor_after(point);
2031            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2032        })
2033    }
2034
2035    pub fn remove_excerpts(
2036        &mut self,
2037        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2038        cx: &mut Context<Self>,
2039    ) {
2040        self.sync(cx);
2041        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2042        if ids.is_empty() {
2043            return;
2044        }
2045
2046        let mut buffers = self.buffers.borrow_mut();
2047        let mut snapshot = self.snapshot.borrow_mut();
2048        let mut new_excerpts = SumTree::default();
2049        let mut cursor = snapshot
2050            .excerpts
2051            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2052        let mut edits = Vec::new();
2053        let mut excerpt_ids = ids.iter().copied().peekable();
2054        let mut removed_buffer_ids = Vec::new();
2055
2056        while let Some(excerpt_id) = excerpt_ids.next() {
2057            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2058            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2059            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2060
2061            if let Some(mut excerpt) = cursor.item() {
2062                if excerpt.id != excerpt_id {
2063                    continue;
2064                }
2065                let mut old_start = cursor.start().1;
2066
2067                // Skip over the removed excerpt.
2068                'remove_excerpts: loop {
2069                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2070                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2071                        if buffer_state.excerpts.is_empty() {
2072                            log::debug!(
2073                                "removing buffer and diff for buffer {}",
2074                                excerpt.buffer_id
2075                            );
2076                            buffers.remove(&excerpt.buffer_id);
2077                            removed_buffer_ids.push(excerpt.buffer_id);
2078                        }
2079                    }
2080                    cursor.next(&());
2081
2082                    // Skip over any subsequent excerpts that are also removed.
2083                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2084                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2085                        if let Some(next_excerpt) = cursor.item() {
2086                            if next_excerpt.locator == *next_locator {
2087                                excerpt_ids.next();
2088                                excerpt = next_excerpt;
2089                                continue 'remove_excerpts;
2090                            }
2091                        }
2092                    }
2093
2094                    break;
2095                }
2096
2097                // When removing the last excerpt, remove the trailing newline from
2098                // the previous excerpt.
2099                if cursor.item().is_none() && old_start.value > 0 {
2100                    old_start.value -= 1;
2101                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2102                }
2103
2104                // Push an edit for the removal of this run of excerpts.
2105                let old_end = cursor.start().1;
2106                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2107                edits.push(Edit {
2108                    old: old_start..old_end,
2109                    new: new_start..new_start,
2110                });
2111            }
2112        }
2113        let suffix = cursor.suffix(&());
2114        let changed_trailing_excerpt = suffix.is_empty();
2115        new_excerpts.append(suffix, &());
2116        drop(cursor);
2117        snapshot.excerpts = new_excerpts;
2118        for buffer_id in removed_buffer_ids {
2119            self.diffs.remove(&buffer_id);
2120            snapshot.diffs.remove(&buffer_id);
2121        }
2122
2123        if changed_trailing_excerpt {
2124            snapshot.trailing_excerpt_update_count += 1;
2125        }
2126
2127        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2128        cx.emit(Event::Edited {
2129            singleton_buffer_edited: false,
2130            edited_buffer: None,
2131        });
2132        cx.emit(Event::ExcerptsRemoved { ids });
2133        cx.notify();
2134    }
2135
2136    pub fn wait_for_anchors<'a>(
2137        &self,
2138        anchors: impl 'a + Iterator<Item = Anchor>,
2139        cx: &mut Context<Self>,
2140    ) -> impl 'static + Future<Output = Result<()>> {
2141        let borrow = self.buffers.borrow();
2142        let mut error = None;
2143        let mut futures = Vec::new();
2144        for anchor in anchors {
2145            if let Some(buffer_id) = anchor.buffer_id {
2146                if let Some(buffer) = borrow.get(&buffer_id) {
2147                    buffer.buffer.update(cx, |buffer, _| {
2148                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2149                    });
2150                } else {
2151                    error = Some(anyhow!(
2152                        "buffer {buffer_id} is not part of this multi-buffer"
2153                    ));
2154                    break;
2155                }
2156            }
2157        }
2158        async move {
2159            if let Some(error) = error {
2160                Err(error)?;
2161            }
2162            for future in futures {
2163                future.await?;
2164            }
2165            Ok(())
2166        }
2167    }
2168
2169    pub fn text_anchor_for_position<T: ToOffset>(
2170        &self,
2171        position: T,
2172        cx: &App,
2173    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2174        let snapshot = self.read(cx);
2175        let anchor = snapshot.anchor_before(position);
2176        let buffer = self
2177            .buffers
2178            .borrow()
2179            .get(&anchor.buffer_id?)?
2180            .buffer
2181            .clone();
2182        Some((buffer, anchor.text_anchor))
2183    }
2184
2185    fn on_buffer_event(
2186        &mut self,
2187        buffer: Entity<Buffer>,
2188        event: &language::BufferEvent,
2189        cx: &mut Context<Self>,
2190    ) {
2191        cx.emit(match event {
2192            language::BufferEvent::Edited => Event::Edited {
2193                singleton_buffer_edited: true,
2194                edited_buffer: Some(buffer.clone()),
2195            },
2196            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2197            language::BufferEvent::Saved => Event::Saved,
2198            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2199            language::BufferEvent::Reloaded => Event::Reloaded,
2200            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2201            language::BufferEvent::LanguageChanged => {
2202                Event::LanguageChanged(buffer.read(cx).remote_id())
2203            }
2204            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2205            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2206            language::BufferEvent::Closed => Event::Closed,
2207            language::BufferEvent::Discarded => Event::Discarded,
2208            language::BufferEvent::CapabilityChanged => {
2209                self.capability = buffer.read(cx).capability();
2210                Event::CapabilityChanged
2211            }
2212            language::BufferEvent::Operation { .. } => return,
2213        });
2214    }
2215
2216    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2217        self.sync(cx);
2218        let mut snapshot = self.snapshot.borrow_mut();
2219        let diff = diff.read(cx);
2220        let buffer_id = diff.buffer_id;
2221        let diff = diff.snapshot(cx);
2222        snapshot.diffs.insert(buffer_id, diff);
2223    }
2224
2225    fn buffer_diff_changed(
2226        &mut self,
2227        diff: Entity<BufferDiff>,
2228        range: Range<text::Anchor>,
2229        cx: &mut Context<Self>,
2230    ) {
2231        self.sync(cx);
2232
2233        let diff = diff.read(cx);
2234        let buffer_id = diff.buffer_id;
2235        let buffers = self.buffers.borrow();
2236        let Some(buffer_state) = buffers.get(&buffer_id) else {
2237            return;
2238        };
2239
2240        let buffer = buffer_state.buffer.read(cx);
2241        let diff_change_range = range.to_offset(buffer);
2242
2243        let new_diff = diff.snapshot(cx);
2244        let mut snapshot = self.snapshot.borrow_mut();
2245        let base_text_changed = snapshot
2246            .diffs
2247            .get(&buffer_id)
2248            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2249
2250        snapshot.diffs.insert(buffer_id, new_diff);
2251
2252        let mut excerpt_edits = Vec::new();
2253        for locator in &buffer_state.excerpts {
2254            let mut cursor = snapshot
2255                .excerpts
2256                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2257            cursor.seek_forward(&Some(locator), Bias::Left, &());
2258            if let Some(excerpt) = cursor.item() {
2259                if excerpt.locator == *locator {
2260                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2261                    if diff_change_range.end < excerpt_buffer_range.start
2262                        || diff_change_range.start > excerpt_buffer_range.end
2263                    {
2264                        continue;
2265                    }
2266                    let excerpt_start = cursor.start().1;
2267                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2268                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2269                        diff_change_range
2270                            .start
2271                            .saturating_sub(excerpt_buffer_range.start),
2272                    );
2273                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2274                        diff_change_range
2275                            .end
2276                            .saturating_sub(excerpt_buffer_range.start),
2277                    );
2278                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2279                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2280                    excerpt_edits.push(Edit {
2281                        old: edit_start..edit_end,
2282                        new: edit_start..edit_end,
2283                    });
2284                }
2285            }
2286        }
2287
2288        self.sync_diff_transforms(
2289            &mut snapshot,
2290            excerpt_edits,
2291            DiffChangeKind::DiffUpdated {
2292                base_changed: base_text_changed,
2293            },
2294        );
2295        cx.emit(Event::Edited {
2296            singleton_buffer_edited: false,
2297            edited_buffer: None,
2298        });
2299    }
2300
2301    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2302        self.buffers
2303            .borrow()
2304            .values()
2305            .map(|state| state.buffer.clone())
2306            .collect()
2307    }
2308
2309    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2310        self.buffers
2311            .borrow()
2312            .get(&buffer_id)
2313            .map(|state| state.buffer.clone())
2314    }
2315
2316    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2317        self.point_to_buffer_offset(point, cx)
2318            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2319    }
2320
2321    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2322        let buffer_id = self
2323            .snapshot
2324            .borrow()
2325            .excerpts
2326            .first()
2327            .map(|excerpt| excerpt.buffer.remote_id());
2328        buffer_id
2329            .and_then(|buffer_id| self.buffer(buffer_id))
2330            .map(|buffer| {
2331                let buffer = buffer.read(cx);
2332                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2333            })
2334            .unwrap_or_else(move || self.language_settings_at(0, cx))
2335    }
2336
2337    pub fn language_settings_at<'a, T: ToOffset>(
2338        &'a self,
2339        point: T,
2340        cx: &'a App,
2341    ) -> Cow<'a, LanguageSettings> {
2342        let mut language = None;
2343        let mut file = None;
2344        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2345            let buffer = buffer.read(cx);
2346            language = buffer.language_at(offset);
2347            file = buffer.file();
2348        }
2349        language_settings(language.map(|l| l.name()), file, cx)
2350    }
2351
2352    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2353        self.buffers
2354            .borrow()
2355            .values()
2356            .for_each(|state| f(&state.buffer))
2357    }
2358
2359    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2360        if let Some(title) = self.title.as_ref() {
2361            return title.into();
2362        }
2363
2364        if let Some(buffer) = self.as_singleton() {
2365            if let Some(file) = buffer.read(cx).file() {
2366                return file.file_name(cx).to_string_lossy();
2367            }
2368        }
2369
2370        "untitled".into()
2371    }
2372
2373    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2374        self.title = Some(title);
2375        cx.notify();
2376    }
2377
2378    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2379    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2380        for buffer_state in self.buffers.borrow().values() {
2381            buffer_state
2382                .buffer
2383                .update(cx, |buffer, _cx| buffer.refresh_preview());
2384        }
2385    }
2386
2387    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2388    pub fn preserve_preview(&self, cx: &App) -> bool {
2389        self.buffers
2390            .borrow()
2391            .values()
2392            .all(|state| state.buffer.read(cx).preserve_preview())
2393    }
2394
2395    #[cfg(any(test, feature = "test-support"))]
2396    pub fn is_parsing(&self, cx: &App) -> bool {
2397        self.as_singleton().unwrap().read(cx).is_parsing()
2398    }
2399
2400    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2401        let buffer_id = diff.read(cx).buffer_id;
2402        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2403        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2404    }
2405
2406    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2407        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2408    }
2409
2410    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2411        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2412    }
2413
2414    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2415        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2416    }
2417
2418    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2419        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2420        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2421    }
2422
2423    pub fn all_diff_hunks_expanded(&self) -> bool {
2424        self.snapshot.borrow().all_diff_hunks_expanded
2425    }
2426
2427    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2428        self.read(cx)
2429            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2430            .nth(1)
2431            .is_some()
2432    }
2433
2434    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2435        let snapshot = self.read(cx);
2436        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2437        let offset_range = range.to_offset(&snapshot);
2438        cursor.seek(&offset_range.start, Bias::Left, &());
2439        while let Some(item) = cursor.item() {
2440            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2441                break;
2442            }
2443            if item.hunk_info().is_some() {
2444                return true;
2445            }
2446            cursor.next(&());
2447        }
2448        false
2449    }
2450
2451    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2452        let snapshot = self.read(cx);
2453        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2454        for range in ranges {
2455            let range = range.to_point(&snapshot);
2456            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2457            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2458            let start = start.saturating_sub(1);
2459            let end = snapshot.len().min(end + 1);
2460            cursor.seek(&start, Bias::Right, &());
2461            while let Some(item) = cursor.item() {
2462                if *cursor.start() >= end {
2463                    break;
2464                }
2465                if item.hunk_info().is_some() {
2466                    return true;
2467                }
2468                cursor.next(&());
2469            }
2470        }
2471        false
2472    }
2473
2474    pub fn expand_or_collapse_diff_hunks_inner(
2475        &mut self,
2476        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2477        expand: bool,
2478        cx: &mut Context<Self>,
2479    ) {
2480        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2481            return;
2482        }
2483        self.sync(cx);
2484        let mut snapshot = self.snapshot.borrow_mut();
2485        let mut excerpt_edits = Vec::new();
2486        for (range, end_excerpt_id) in ranges {
2487            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2488                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2489                    continue;
2490                }
2491                let start = Anchor::in_buffer(
2492                    diff_hunk.excerpt_id,
2493                    diff_hunk.buffer_id,
2494                    diff_hunk.buffer_range.start,
2495                );
2496                let end = Anchor::in_buffer(
2497                    diff_hunk.excerpt_id,
2498                    diff_hunk.buffer_id,
2499                    diff_hunk.buffer_range.end,
2500                );
2501                let start = snapshot.excerpt_offset_for_anchor(&start);
2502                let end = snapshot.excerpt_offset_for_anchor(&end);
2503                excerpt_edits.push(text::Edit {
2504                    old: start..end,
2505                    new: start..end,
2506                });
2507            }
2508        }
2509
2510        self.sync_diff_transforms(
2511            &mut snapshot,
2512            excerpt_edits,
2513            DiffChangeKind::ExpandOrCollapseHunks { expand },
2514        );
2515        cx.emit(Event::DiffHunksToggled);
2516        cx.emit(Event::Edited {
2517            singleton_buffer_edited: false,
2518            edited_buffer: None,
2519        });
2520    }
2521
2522    pub fn expand_or_collapse_diff_hunks(
2523        &mut self,
2524        ranges: Vec<Range<Anchor>>,
2525        expand: bool,
2526        cx: &mut Context<Self>,
2527    ) {
2528        let snapshot = self.snapshot.borrow().clone();
2529        let ranges = ranges.iter().map(move |range| {
2530            let end_excerpt_id = range.end.excerpt_id;
2531            let range = range.to_point(&snapshot);
2532            let mut peek_end = range.end;
2533            if range.end.row < snapshot.max_row().0 {
2534                peek_end = Point::new(range.end.row + 1, 0);
2535            };
2536            (range.start..peek_end, end_excerpt_id)
2537        });
2538        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2539    }
2540
2541    pub fn resize_excerpt(
2542        &mut self,
2543        id: ExcerptId,
2544        range: Range<text::Anchor>,
2545        cx: &mut Context<Self>,
2546    ) {
2547        self.sync(cx);
2548
2549        let mut snapshot = self.snapshot.borrow_mut();
2550        let locator = snapshot.excerpt_locator_for_id(id);
2551        let mut new_excerpts = SumTree::default();
2552        let mut cursor = snapshot
2553            .excerpts
2554            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2555        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2556
2557        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2558        new_excerpts.append(prefix, &());
2559
2560        let mut excerpt = cursor.item().unwrap().clone();
2561        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2562
2563        excerpt.range.context.start = range.start;
2564        excerpt.range.context.end = range.end;
2565        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2566
2567        excerpt.text_summary = excerpt
2568            .buffer
2569            .text_summary_for_range(excerpt.range.context.clone());
2570
2571        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2572        let old_start_offset = cursor.start().1;
2573        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2574        let edit = Edit {
2575            old: old_start_offset..old_start_offset + old_text_len,
2576            new: new_start_offset..new_start_offset + new_text_len,
2577        };
2578
2579        if let Some(last_edit) = edits.last_mut() {
2580            if last_edit.old.end == edit.old.start {
2581                last_edit.old.end = edit.old.end;
2582                last_edit.new.end = edit.new.end;
2583            } else {
2584                edits.push(edit);
2585            }
2586        } else {
2587            edits.push(edit);
2588        }
2589
2590        new_excerpts.push(excerpt, &());
2591
2592        cursor.next(&());
2593
2594        new_excerpts.append(cursor.suffix(&()), &());
2595
2596        drop(cursor);
2597        snapshot.excerpts = new_excerpts;
2598
2599        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2600        cx.emit(Event::Edited {
2601            singleton_buffer_edited: false,
2602            edited_buffer: None,
2603        });
2604        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2605        cx.notify();
2606    }
2607
2608    pub fn expand_excerpts(
2609        &mut self,
2610        ids: impl IntoIterator<Item = ExcerptId>,
2611        line_count: u32,
2612        direction: ExpandExcerptDirection,
2613        cx: &mut Context<Self>,
2614    ) {
2615        if line_count == 0 {
2616            return;
2617        }
2618        self.sync(cx);
2619        let mut snapshot = self.snapshot.borrow_mut();
2620
2621        let ids = ids.into_iter().collect::<Vec<_>>();
2622        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2623        let mut new_excerpts = SumTree::default();
2624        let mut cursor = snapshot
2625            .excerpts
2626            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2627        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2628
2629        for locator in &locators {
2630            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2631            new_excerpts.append(prefix, &());
2632
2633            let mut excerpt = cursor.item().unwrap().clone();
2634            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2635
2636            let up_line_count = if direction.should_expand_up() {
2637                line_count
2638            } else {
2639                0
2640            };
2641
2642            let start_row = excerpt
2643                .range
2644                .context
2645                .start
2646                .to_point(&excerpt.buffer)
2647                .row
2648                .saturating_sub(up_line_count);
2649            let start_point = Point::new(start_row, 0);
2650            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2651
2652            let down_line_count = if direction.should_expand_down() {
2653                line_count
2654            } else {
2655                0
2656            };
2657
2658            let mut end_point = excerpt.buffer.clip_point(
2659                excerpt.range.context.end.to_point(&excerpt.buffer)
2660                    + Point::new(down_line_count, 0),
2661                Bias::Left,
2662            );
2663            end_point.column = excerpt.buffer.line_len(end_point.row);
2664            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2665            excerpt.max_buffer_row = end_point.row;
2666
2667            excerpt.text_summary = excerpt
2668                .buffer
2669                .text_summary_for_range(excerpt.range.context.clone());
2670
2671            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2672            let old_start_offset = cursor.start().1;
2673            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2674            let edit = Edit {
2675                old: old_start_offset..old_start_offset + old_text_len,
2676                new: new_start_offset..new_start_offset + new_text_len,
2677            };
2678
2679            if let Some(last_edit) = edits.last_mut() {
2680                if last_edit.old.end == edit.old.start {
2681                    last_edit.old.end = edit.old.end;
2682                    last_edit.new.end = edit.new.end;
2683                } else {
2684                    edits.push(edit);
2685                }
2686            } else {
2687                edits.push(edit);
2688            }
2689
2690            new_excerpts.push(excerpt, &());
2691
2692            cursor.next(&());
2693        }
2694
2695        new_excerpts.append(cursor.suffix(&()), &());
2696
2697        drop(cursor);
2698        snapshot.excerpts = new_excerpts;
2699
2700        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2701        cx.emit(Event::Edited {
2702            singleton_buffer_edited: false,
2703            edited_buffer: None,
2704        });
2705        cx.emit(Event::ExcerptsExpanded { ids });
2706        cx.notify();
2707    }
2708
2709    fn sync(&self, cx: &App) {
2710        let mut snapshot = self.snapshot.borrow_mut();
2711        let mut excerpts_to_edit = Vec::new();
2712        let mut non_text_state_updated = false;
2713        let mut is_dirty = false;
2714        let mut has_deleted_file = false;
2715        let mut has_conflict = false;
2716        let mut edited = false;
2717        let mut buffers = self.buffers.borrow_mut();
2718        for buffer_state in buffers.values_mut() {
2719            let buffer = buffer_state.buffer.read(cx);
2720            let version = buffer.version();
2721            let non_text_state_update_count = buffer.non_text_state_update_count();
2722
2723            let buffer_edited = version.changed_since(&buffer_state.last_version);
2724            let buffer_non_text_state_updated =
2725                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2726            if buffer_edited || buffer_non_text_state_updated {
2727                buffer_state.last_version = version;
2728                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2729                excerpts_to_edit.extend(
2730                    buffer_state
2731                        .excerpts
2732                        .iter()
2733                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2734                );
2735            }
2736
2737            edited |= buffer_edited;
2738            non_text_state_updated |= buffer_non_text_state_updated;
2739            is_dirty |= buffer.is_dirty();
2740            has_deleted_file |= buffer
2741                .file()
2742                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2743            has_conflict |= buffer.has_conflict();
2744        }
2745        if edited {
2746            snapshot.edit_count += 1;
2747        }
2748        if non_text_state_updated {
2749            snapshot.non_text_state_update_count += 1;
2750        }
2751        snapshot.is_dirty = is_dirty;
2752        snapshot.has_deleted_file = has_deleted_file;
2753        snapshot.has_conflict = has_conflict;
2754
2755        for (id, diff) in self.diffs.iter() {
2756            if snapshot.diffs.get(&id).is_none() {
2757                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2758            }
2759        }
2760
2761        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2762
2763        let mut edits = Vec::new();
2764        let mut new_excerpts = SumTree::default();
2765        let mut cursor = snapshot
2766            .excerpts
2767            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2768
2769        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2770            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2771            let old_excerpt = cursor.item().unwrap();
2772            let buffer = buffer.read(cx);
2773            let buffer_id = buffer.remote_id();
2774
2775            let mut new_excerpt;
2776            if buffer_edited {
2777                edits.extend(
2778                    buffer
2779                        .edits_since_in_range::<usize>(
2780                            old_excerpt.buffer.version(),
2781                            old_excerpt.range.context.clone(),
2782                        )
2783                        .map(|edit| {
2784                            let excerpt_old_start = cursor.start().1;
2785                            let excerpt_new_start =
2786                                ExcerptOffset::new(new_excerpts.summary().text.len);
2787                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2788                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2789                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2790                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2791                            Edit {
2792                                old: old_start..old_end,
2793                                new: new_start..new_end,
2794                            }
2795                        }),
2796                );
2797
2798                new_excerpt = Excerpt::new(
2799                    old_excerpt.id,
2800                    locator.clone(),
2801                    buffer_id,
2802                    buffer.snapshot(),
2803                    old_excerpt.range.clone(),
2804                    old_excerpt.has_trailing_newline,
2805                );
2806            } else {
2807                new_excerpt = old_excerpt.clone();
2808                new_excerpt.buffer = buffer.snapshot();
2809            }
2810
2811            new_excerpts.push(new_excerpt, &());
2812            cursor.next(&());
2813        }
2814        new_excerpts.append(cursor.suffix(&()), &());
2815
2816        drop(cursor);
2817        snapshot.excerpts = new_excerpts;
2818
2819        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2820    }
2821
2822    fn sync_diff_transforms(
2823        &self,
2824        snapshot: &mut MultiBufferSnapshot,
2825        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2826        change_kind: DiffChangeKind,
2827    ) {
2828        if excerpt_edits.is_empty() {
2829            return;
2830        }
2831
2832        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2833        let mut old_diff_transforms = snapshot
2834            .diff_transforms
2835            .cursor::<(ExcerptOffset, usize)>(&());
2836        let mut new_diff_transforms = SumTree::default();
2837        let mut old_expanded_hunks = HashSet::default();
2838        let mut output_edits = Vec::new();
2839        let mut output_delta = 0_isize;
2840        let mut at_transform_boundary = true;
2841        let mut end_of_current_insert = None;
2842
2843        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2844        while let Some(edit) = excerpt_edits.next() {
2845            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2846            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2847                excerpts.prev(&());
2848            }
2849
2850            // Keep any transforms that are before the edit.
2851            if at_transform_boundary {
2852                at_transform_boundary = false;
2853                let transforms_before_edit =
2854                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2855                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2856                if let Some(transform) = old_diff_transforms.item() {
2857                    if old_diff_transforms.end(&()).0 == edit.old.start
2858                        && old_diff_transforms.start().0 < edit.old.start
2859                    {
2860                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2861                        old_diff_transforms.next(&());
2862                    }
2863                }
2864            }
2865
2866            // Compute the start of the edit in output coordinates.
2867            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2868            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2869            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2870
2871            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2872                &edit,
2873                &mut excerpts,
2874                &mut old_diff_transforms,
2875                &mut new_diff_transforms,
2876                &mut end_of_current_insert,
2877                &mut old_expanded_hunks,
2878                &snapshot,
2879                change_kind,
2880            );
2881
2882            // Compute the end of the edit in output coordinates.
2883            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2884            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2885            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2886            let edit_new_end =
2887                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2888            let output_edit = Edit {
2889                old: edit_old_start..edit_old_end,
2890                new: edit_new_start..edit_new_end,
2891            };
2892
2893            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2894            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2895            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2896                output_edits.push(output_edit);
2897            }
2898
2899            // If this is the last edit that intersects the current diff transform,
2900            // then recreate the content up to the end of this transform, to prepare
2901            // for reusing additional slices of the old transforms.
2902            if excerpt_edits.peek().map_or(true, |next_edit| {
2903                next_edit.old.start >= old_diff_transforms.end(&()).0
2904            }) {
2905                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2906                    && match old_diff_transforms.item() {
2907                        Some(DiffTransform::BufferContent {
2908                            inserted_hunk_info: Some(hunk),
2909                            ..
2910                        }) => excerpts.item().is_some_and(|excerpt| {
2911                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2912                        }),
2913                        _ => true,
2914                    };
2915
2916                let mut excerpt_offset = edit.new.end;
2917                if !keep_next_old_transform {
2918                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2919                    old_diff_transforms.next(&());
2920                }
2921
2922                old_expanded_hunks.clear();
2923                self.push_buffer_content_transform(
2924                    &snapshot,
2925                    &mut new_diff_transforms,
2926                    excerpt_offset,
2927                    end_of_current_insert,
2928                );
2929                at_transform_boundary = true;
2930            }
2931        }
2932
2933        // Keep any transforms that are after the last edit.
2934        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2935
2936        // Ensure there's always at least one buffer content transform.
2937        if new_diff_transforms.is_empty() {
2938            new_diff_transforms.push(
2939                DiffTransform::BufferContent {
2940                    summary: Default::default(),
2941                    inserted_hunk_info: None,
2942                },
2943                &(),
2944            );
2945        }
2946
2947        self.subscriptions.publish(output_edits);
2948        drop(old_diff_transforms);
2949        drop(excerpts);
2950        snapshot.diff_transforms = new_diff_transforms;
2951        snapshot.edit_count += 1;
2952
2953        #[cfg(any(test, feature = "test-support"))]
2954        snapshot.check_invariants();
2955    }
2956
2957    #[allow(clippy::too_many_arguments)]
2958    fn recompute_diff_transforms_for_edit(
2959        &self,
2960        edit: &Edit<TypedOffset<Excerpt>>,
2961        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2962        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2963        new_diff_transforms: &mut SumTree<DiffTransform>,
2964        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2965        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2966        snapshot: &MultiBufferSnapshot,
2967        change_kind: DiffChangeKind,
2968    ) -> bool {
2969        log::trace!(
2970            "recomputing diff transform for edit {:?} => {:?}",
2971            edit.old.start.value..edit.old.end.value,
2972            edit.new.start.value..edit.new.end.value
2973        );
2974
2975        // Record which hunks were previously expanded.
2976        while let Some(item) = old_diff_transforms.item() {
2977            if let Some(hunk_info) = item.hunk_info() {
2978                log::trace!(
2979                    "previously expanded hunk at {}",
2980                    old_diff_transforms.start().0
2981                );
2982                old_expanded_hunks.insert(hunk_info);
2983            }
2984            if old_diff_transforms.end(&()).0 > edit.old.end {
2985                break;
2986            }
2987            old_diff_transforms.next(&());
2988        }
2989
2990        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2991        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2992        if old_expanded_hunks.is_empty()
2993            && change_kind == DiffChangeKind::BufferEdited
2994            && !all_diff_hunks_expanded
2995        {
2996            return false;
2997        }
2998
2999        // Visit each excerpt that intersects the edit.
3000        let mut did_expand_hunks = false;
3001        while let Some(excerpt) = excerpts.item() {
3002            // Recompute the expanded hunks in the portion of the excerpt that
3003            // intersects the edit.
3004            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3005                let buffer = &excerpt.buffer;
3006                let excerpt_start = *excerpts.start();
3007                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3008                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3009                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3010                let edit_buffer_start =
3011                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3012                let edit_buffer_end =
3013                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3014                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3015                let edit_anchor_range =
3016                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3017
3018                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3019                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3020                        continue;
3021                    }
3022
3023                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3024                    if hunk_buffer_range.start < excerpt_buffer_start {
3025                        log::trace!("skipping hunk that starts before excerpt");
3026                        continue;
3027                    }
3028
3029                    let hunk_info = DiffTransformHunkInfo {
3030                        excerpt_id: excerpt.id,
3031                        hunk_start_anchor: hunk.buffer_range.start,
3032                        hunk_secondary_status: hunk.secondary_status,
3033                    };
3034
3035                    let hunk_excerpt_start = excerpt_start
3036                        + ExcerptOffset::new(
3037                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3038                        );
3039                    let hunk_excerpt_end = excerpt_end.min(
3040                        excerpt_start
3041                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3042                    );
3043
3044                    self.push_buffer_content_transform(
3045                        snapshot,
3046                        new_diff_transforms,
3047                        hunk_excerpt_start,
3048                        *end_of_current_insert,
3049                    );
3050
3051                    // For every existing hunk, determine if it was previously expanded
3052                    // and if it should currently be expanded.
3053                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3054                    let should_expand_hunk = match &change_kind {
3055                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3056                            was_previously_expanded || all_diff_hunks_expanded
3057                        }
3058                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3059                            let intersects = hunk_buffer_range.is_empty()
3060                                || hunk_buffer_range.end > edit_buffer_start;
3061                            if *expand {
3062                                intersects || was_previously_expanded || all_diff_hunks_expanded
3063                            } else {
3064                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3065                            }
3066                        }
3067                        _ => was_previously_expanded || all_diff_hunks_expanded,
3068                    };
3069
3070                    if should_expand_hunk {
3071                        did_expand_hunks = true;
3072                        log::trace!(
3073                            "expanding hunk {:?}, excerpt:{:?}",
3074                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3075                            excerpt.id
3076                        );
3077
3078                        if !hunk.diff_base_byte_range.is_empty()
3079                            && hunk_buffer_range.start >= edit_buffer_start
3080                            && hunk_buffer_range.start <= excerpt_buffer_end
3081                        {
3082                            let base_text = diff.base_text();
3083                            let mut text_cursor =
3084                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3085                            let mut base_text_summary =
3086                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3087
3088                            let mut has_trailing_newline = false;
3089                            if base_text_summary.last_line_chars > 0 {
3090                                base_text_summary += TextSummary::newline();
3091                                has_trailing_newline = true;
3092                            }
3093
3094                            new_diff_transforms.push(
3095                                DiffTransform::DeletedHunk {
3096                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3097                                    summary: base_text_summary,
3098                                    buffer_id: excerpt.buffer_id,
3099                                    hunk_info,
3100                                    has_trailing_newline,
3101                                },
3102                                &(),
3103                            );
3104                        }
3105
3106                        if !hunk_buffer_range.is_empty() {
3107                            *end_of_current_insert =
3108                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3109                        }
3110                    }
3111                }
3112            }
3113
3114            if excerpts.end(&()) <= edit.new.end {
3115                excerpts.next(&());
3116            } else {
3117                break;
3118            }
3119        }
3120
3121        did_expand_hunks || !old_expanded_hunks.is_empty()
3122    }
3123
3124    fn append_diff_transforms(
3125        &self,
3126        new_transforms: &mut SumTree<DiffTransform>,
3127        subtree: SumTree<DiffTransform>,
3128    ) {
3129        if let Some(DiffTransform::BufferContent {
3130            inserted_hunk_info,
3131            summary,
3132        }) = subtree.first()
3133        {
3134            if self.extend_last_buffer_content_transform(
3135                new_transforms,
3136                *inserted_hunk_info,
3137                *summary,
3138            ) {
3139                let mut cursor = subtree.cursor::<()>(&());
3140                cursor.next(&());
3141                cursor.next(&());
3142                new_transforms.append(cursor.suffix(&()), &());
3143                return;
3144            }
3145        }
3146        new_transforms.append(subtree, &());
3147    }
3148
3149    fn push_diff_transform(
3150        &self,
3151        new_transforms: &mut SumTree<DiffTransform>,
3152        transform: DiffTransform,
3153    ) {
3154        if let DiffTransform::BufferContent {
3155            inserted_hunk_info: inserted_hunk_anchor,
3156            summary,
3157        } = transform
3158        {
3159            if self.extend_last_buffer_content_transform(
3160                new_transforms,
3161                inserted_hunk_anchor,
3162                summary,
3163            ) {
3164                return;
3165            }
3166        }
3167        new_transforms.push(transform, &());
3168    }
3169
3170    fn push_buffer_content_transform(
3171        &self,
3172        old_snapshot: &MultiBufferSnapshot,
3173        new_transforms: &mut SumTree<DiffTransform>,
3174        end_offset: ExcerptOffset,
3175        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3176    ) {
3177        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3178            (end_offset.min(insertion_end_offset), Some(hunk_info))
3179        });
3180        let unchanged_region = [(end_offset, None)];
3181
3182        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3183        {
3184            let start_offset = new_transforms.summary().excerpt_len();
3185            if end_offset <= start_offset {
3186                continue;
3187            }
3188            let summary_to_add = old_snapshot
3189                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3190
3191            if !self.extend_last_buffer_content_transform(
3192                new_transforms,
3193                inserted_hunk_info,
3194                summary_to_add,
3195            ) {
3196                new_transforms.push(
3197                    DiffTransform::BufferContent {
3198                        summary: summary_to_add,
3199                        inserted_hunk_info,
3200                    },
3201                    &(),
3202                )
3203            }
3204        }
3205    }
3206
3207    fn extend_last_buffer_content_transform(
3208        &self,
3209        new_transforms: &mut SumTree<DiffTransform>,
3210        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3211        summary_to_add: TextSummary,
3212    ) -> bool {
3213        let mut did_extend = false;
3214        new_transforms.update_last(
3215            |last_transform| {
3216                if let DiffTransform::BufferContent {
3217                    summary,
3218                    inserted_hunk_info: inserted_hunk_anchor,
3219                } = last_transform
3220                {
3221                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3222                        *summary += summary_to_add;
3223                        did_extend = true;
3224                    }
3225                }
3226            },
3227            &(),
3228        );
3229        did_extend
3230    }
3231}
3232
3233#[cfg(any(test, feature = "test-support"))]
3234impl MultiBuffer {
3235    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3236        let buffer = cx.new(|cx| Buffer::local(text, cx));
3237        cx.new(|cx| Self::singleton(buffer, cx))
3238    }
3239
3240    pub fn build_multi<const COUNT: usize>(
3241        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3242        cx: &mut gpui::App,
3243    ) -> Entity<Self> {
3244        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3245        for (text, ranges) in excerpts {
3246            let buffer = cx.new(|cx| Buffer::local(text, cx));
3247            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3248                context: range,
3249                primary: None,
3250            });
3251            multi.update(cx, |multi, cx| {
3252                multi.push_excerpts(buffer, excerpt_ranges, cx)
3253            });
3254        }
3255
3256        multi
3257    }
3258
3259    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3260        cx.new(|cx| Self::singleton(buffer, cx))
3261    }
3262
3263    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3264        cx.new(|cx| {
3265            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3266            let mutation_count = rng.gen_range(1..=5);
3267            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3268            multibuffer
3269        })
3270    }
3271
3272    pub fn randomly_edit(
3273        &mut self,
3274        rng: &mut impl rand::Rng,
3275        edit_count: usize,
3276        cx: &mut Context<Self>,
3277    ) {
3278        use util::RandomCharIter;
3279
3280        let snapshot = self.read(cx);
3281        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3282        let mut last_end = None;
3283        for _ in 0..edit_count {
3284            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3285                break;
3286            }
3287
3288            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3289            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3290            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3291            last_end = Some(end);
3292
3293            let mut range = start..end;
3294            if rng.gen_bool(0.2) {
3295                mem::swap(&mut range.start, &mut range.end);
3296            }
3297
3298            let new_text_len = rng.gen_range(0..10);
3299            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3300
3301            edits.push((range, new_text.into()));
3302        }
3303        log::info!("mutating multi-buffer with {:?}", edits);
3304        drop(snapshot);
3305
3306        self.edit(edits, None, cx);
3307    }
3308
3309    pub fn randomly_edit_excerpts(
3310        &mut self,
3311        rng: &mut impl rand::Rng,
3312        mutation_count: usize,
3313        cx: &mut Context<Self>,
3314    ) {
3315        use rand::prelude::*;
3316        use std::env;
3317        use util::RandomCharIter;
3318
3319        let max_excerpts = env::var("MAX_EXCERPTS")
3320            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3321            .unwrap_or(5);
3322
3323        let mut buffers = Vec::new();
3324        for _ in 0..mutation_count {
3325            if rng.gen_bool(0.05) {
3326                log::info!("Clearing multi-buffer");
3327                self.clear(cx);
3328                continue;
3329            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3330                let ids = self.excerpt_ids();
3331                let mut excerpts = HashSet::default();
3332                for _ in 0..rng.gen_range(0..ids.len()) {
3333                    excerpts.extend(ids.choose(rng).copied());
3334                }
3335
3336                let line_count = rng.gen_range(0..5);
3337
3338                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3339
3340                self.expand_excerpts(
3341                    excerpts.iter().cloned(),
3342                    line_count,
3343                    ExpandExcerptDirection::UpAndDown,
3344                    cx,
3345                );
3346                continue;
3347            }
3348
3349            let excerpt_ids = self.excerpt_ids();
3350            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3351                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3352                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3353                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3354                    let buffer = buffers.last().unwrap().read(cx);
3355                    log::info!(
3356                        "Creating new buffer {} with text: {:?}",
3357                        buffer.remote_id(),
3358                        buffer.text()
3359                    );
3360                    buffers.last().unwrap().clone()
3361                } else {
3362                    self.buffers
3363                        .borrow()
3364                        .values()
3365                        .choose(rng)
3366                        .unwrap()
3367                        .buffer
3368                        .clone()
3369                };
3370
3371                let buffer = buffer_handle.read(cx);
3372                let buffer_text = buffer.text();
3373                let ranges = (0..rng.gen_range(0..5))
3374                    .map(|_| {
3375                        let end_ix =
3376                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3377                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3378                        ExcerptRange {
3379                            context: start_ix..end_ix,
3380                            primary: None,
3381                        }
3382                    })
3383                    .collect::<Vec<_>>();
3384                log::info!(
3385                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3386                    buffer_handle.read(cx).remote_id(),
3387                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3388                    ranges
3389                        .iter()
3390                        .map(|r| &buffer_text[r.context.clone()])
3391                        .collect::<Vec<_>>()
3392                );
3393
3394                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3395                log::info!("Inserted with ids: {:?}", excerpt_id);
3396            } else {
3397                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3398                let mut excerpts_to_remove = excerpt_ids
3399                    .choose_multiple(rng, remove_count)
3400                    .cloned()
3401                    .collect::<Vec<_>>();
3402                let snapshot = self.snapshot.borrow();
3403                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3404                drop(snapshot);
3405                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3406                self.remove_excerpts(excerpts_to_remove, cx);
3407            }
3408        }
3409    }
3410
3411    pub fn randomly_mutate(
3412        &mut self,
3413        rng: &mut impl rand::Rng,
3414        mutation_count: usize,
3415        cx: &mut Context<Self>,
3416    ) {
3417        use rand::prelude::*;
3418
3419        if rng.gen_bool(0.7) || self.singleton {
3420            let buffer = self
3421                .buffers
3422                .borrow()
3423                .values()
3424                .choose(rng)
3425                .map(|state| state.buffer.clone());
3426
3427            if let Some(buffer) = buffer {
3428                buffer.update(cx, |buffer, cx| {
3429                    if rng.gen() {
3430                        buffer.randomly_edit(rng, mutation_count, cx);
3431                    } else {
3432                        buffer.randomly_undo_redo(rng, cx);
3433                    }
3434                });
3435            } else {
3436                self.randomly_edit(rng, mutation_count, cx);
3437            }
3438        } else {
3439            self.randomly_edit_excerpts(rng, mutation_count, cx);
3440        }
3441
3442        self.check_invariants(cx);
3443    }
3444
3445    fn check_invariants(&self, cx: &App) {
3446        self.read(cx).check_invariants();
3447    }
3448}
3449
3450impl EventEmitter<Event> for MultiBuffer {}
3451
3452impl MultiBufferSnapshot {
3453    pub fn text(&self) -> String {
3454        self.chunks(0..self.len(), false)
3455            .map(|chunk| chunk.text)
3456            .collect()
3457    }
3458
3459    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3460        self.reversed_chunks_in_range(0..position.to_offset(self))
3461            .flat_map(|c| c.chars().rev())
3462    }
3463
3464    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3465        let mut cursor = self.cursor::<usize>();
3466        cursor.seek(&range.end);
3467        let current_chunks = cursor.region().as_ref().map(|region| {
3468            let start_overshoot = range.start.saturating_sub(region.range.start);
3469            let end_overshoot = range.end - region.range.start;
3470            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3471            let start = region.buffer_range.start + start_overshoot;
3472            region.buffer.reversed_chunks_in_range(start..end)
3473        });
3474        ReversedMultiBufferChunks {
3475            cursor,
3476            current_chunks,
3477            start: range.start,
3478            offset: range.end,
3479        }
3480    }
3481
3482    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3483        let offset = position.to_offset(self);
3484        self.text_for_range(offset..self.len())
3485            .flat_map(|chunk| chunk.chars())
3486    }
3487
3488    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3489        self.chunks(range, false).map(|chunk| chunk.text)
3490    }
3491
3492    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3493        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3494            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3495    }
3496
3497    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3498    where
3499        T: ToOffset,
3500    {
3501        let position = position.to_offset(self);
3502        position == self.clip_offset(position, Bias::Left)
3503            && self
3504                .bytes_in_range(position..self.len())
3505                .flatten()
3506                .copied()
3507                .take(needle.len())
3508                .eq(needle.bytes())
3509    }
3510
3511    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3512        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3513    }
3514
3515    pub fn diff_hunks_in_range<T: ToPoint>(
3516        &self,
3517        range: Range<T>,
3518    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3519        let query_range = range.start.to_point(self)..range.end.to_point(self);
3520        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3521            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
3522                log::debug!("no diff found for {:?}", buffer.remote_id());
3523                return None;
3524            };
3525            let buffer_start = buffer.anchor_before(buffer_range.start);
3526            let buffer_end = buffer.anchor_after(buffer_range.end);
3527            Some(
3528                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3529                    .filter_map(|hunk| {
3530                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3531                            return None;
3532                        }
3533                        Some((hunk.range.clone(), hunk))
3534                    }),
3535            )
3536        })
3537        .filter_map(move |(range, hunk, excerpt)| {
3538            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3539            {
3540                return None;
3541            }
3542            let end_row = if range.end.column == 0 {
3543                range.end.row
3544            } else {
3545                range.end.row + 1
3546            };
3547            Some(MultiBufferDiffHunk {
3548                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3549                buffer_id: excerpt.buffer_id,
3550                excerpt_id: excerpt.id,
3551                buffer_range: hunk.buffer_range.clone(),
3552                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3553                secondary_status: hunk.secondary_status,
3554            })
3555        })
3556    }
3557
3558    pub fn excerpt_ids_for_range<T: ToOffset>(
3559        &self,
3560        range: Range<T>,
3561    ) -> impl Iterator<Item = ExcerptId> + '_ {
3562        let range = range.start.to_offset(self)..range.end.to_offset(self);
3563        let mut cursor = self.cursor::<usize>();
3564        cursor.seek(&range.start);
3565        std::iter::from_fn(move || {
3566            let region = cursor.region()?;
3567            if region.range.start >= range.end {
3568                return None;
3569            }
3570            cursor.next_excerpt();
3571            Some(region.excerpt.id)
3572        })
3573    }
3574
3575    pub fn buffer_ids_for_range<T: ToOffset>(
3576        &self,
3577        range: Range<T>,
3578    ) -> impl Iterator<Item = BufferId> + '_ {
3579        let range = range.start.to_offset(self)..range.end.to_offset(self);
3580        let mut cursor = self.cursor::<usize>();
3581        cursor.seek(&range.start);
3582        std::iter::from_fn(move || {
3583            let region = cursor.region()?;
3584            if region.range.start > range.end
3585                || region.range.start == range.end && region.range.start > range.start
3586            {
3587                return None;
3588            }
3589            cursor.next_excerpt();
3590            Some(region.excerpt.buffer_id)
3591        })
3592    }
3593
3594    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3595        &self,
3596        ranges: impl Iterator<Item = Range<T>>,
3597    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3598        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3599    }
3600
3601    pub fn range_to_buffer_ranges<T: ToOffset>(
3602        &self,
3603        range: Range<T>,
3604    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3605        let start = range.start.to_offset(&self);
3606        let end = range.end.to_offset(&self);
3607
3608        let mut cursor = self.cursor::<usize>();
3609        cursor.seek(&start);
3610
3611        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3612        while let Some(region) = cursor.region() {
3613            if region.range.start > end {
3614                break;
3615            }
3616            if region.is_main_buffer {
3617                let start_overshoot = start.saturating_sub(region.range.start);
3618                let end_overshoot = end.saturating_sub(region.range.start);
3619                let start = region
3620                    .buffer_range
3621                    .end
3622                    .min(region.buffer_range.start + start_overshoot);
3623                let end = region
3624                    .buffer_range
3625                    .end
3626                    .min(region.buffer_range.start + end_overshoot);
3627                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3628                    *excerpt_id == region.excerpt.id && prev_range.end == start
3629                }) {
3630                    prev.1.end = end;
3631                } else {
3632                    result.push((region.buffer, start..end, region.excerpt.id));
3633                }
3634            }
3635            cursor.next();
3636        }
3637        result
3638    }
3639
3640    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3641        &self,
3642        range: Range<T>,
3643    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3644        let start = range.start.to_offset(&self);
3645        let end = range.end.to_offset(&self);
3646
3647        let mut cursor = self.cursor::<usize>();
3648        cursor.seek(&start);
3649
3650        std::iter::from_fn(move || {
3651            let region = cursor.region()?;
3652            if region.range.start > end {
3653                return None;
3654            }
3655            let start_overshoot = start.saturating_sub(region.range.start);
3656            let end_overshoot = end.saturating_sub(region.range.start);
3657            let start = region
3658                .buffer_range
3659                .end
3660                .min(region.buffer_range.start + start_overshoot);
3661            let end = region
3662                .buffer_range
3663                .end
3664                .min(region.buffer_range.start + end_overshoot);
3665
3666            let region_excerpt_id = region.excerpt.id;
3667            let deleted_hunk_anchor = if region.is_main_buffer {
3668                None
3669            } else {
3670                Some(self.anchor_before(region.range.start))
3671            };
3672            let result = (
3673                region.buffer,
3674                start..end,
3675                region_excerpt_id,
3676                deleted_hunk_anchor,
3677            );
3678            cursor.next();
3679            Some(result)
3680        })
3681    }
3682
3683    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3684    /// coordinates.
3685    ///
3686    /// The given callback will be called for every excerpt intersecting the given range. It will
3687    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3688    /// The callback should return an iterator of metadata items from that buffer, each paired
3689    /// with a buffer range.
3690    ///
3691    /// The returned iterator yields each of these metadata items, paired with its range in
3692    /// multi-buffer coordinates.
3693    fn lift_buffer_metadata<'a, D, M, I>(
3694        &'a self,
3695        query_range: Range<D>,
3696        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3697    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3698    where
3699        I: Iterator<Item = (Range<D>, M)> + 'a,
3700        D: TextDimension + Ord + Sub<D, Output = D>,
3701    {
3702        let max_position = D::from_text_summary(&self.text_summary());
3703        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3704        let mut cursor = self.cursor::<D>();
3705
3706        // Find the excerpt and buffer offset where the given range ends.
3707        cursor.seek(&query_range.end);
3708        let mut range_end = None;
3709        while let Some(region) = cursor.region() {
3710            if region.is_main_buffer {
3711                let mut buffer_end = region.buffer_range.start;
3712                let overshoot = if query_range.end > region.range.start {
3713                    query_range.end - region.range.start
3714                } else {
3715                    D::default()
3716                };
3717                buffer_end.add_assign(&overshoot);
3718                range_end = Some((region.excerpt.id, buffer_end));
3719                break;
3720            }
3721            cursor.next();
3722        }
3723
3724        cursor.seek(&query_range.start);
3725
3726        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3727            if region.range.start > D::zero(&()) {
3728                cursor.prev()
3729            }
3730        }
3731
3732        iter::from_fn(move || loop {
3733            let excerpt = cursor.excerpt()?;
3734
3735            // If we have already retrieved metadata for this excerpt, continue to use it.
3736            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3737                .as_mut()
3738                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3739            {
3740                Some(metadata)
3741            }
3742            // Otherwise, compute the intersection of the input range with the excerpt's range,
3743            // and retrieve the metadata for the resulting range.
3744            else {
3745                let region = cursor.region()?;
3746                let mut buffer_start;
3747                if region.is_main_buffer {
3748                    buffer_start = region.buffer_range.start;
3749                    if query_range.start > region.range.start {
3750                        let overshoot = query_range.start - region.range.start;
3751                        buffer_start.add_assign(&overshoot);
3752                    }
3753                    buffer_start = buffer_start.min(region.buffer_range.end);
3754                } else {
3755                    buffer_start = cursor.main_buffer_position()?;
3756                };
3757                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3758                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3759                    if excerpt.id == end_excerpt_id {
3760                        buffer_end = buffer_end.min(end_buffer_offset);
3761                    }
3762                }
3763
3764                if let Some(iterator) =
3765                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3766                {
3767                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3768                } else {
3769                    None
3770                }
3771            };
3772
3773            // Visit each metadata item.
3774            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3775            {
3776                // Find the multibuffer regions that contain the start and end of
3777                // the metadata item's range.
3778                if metadata_buffer_range.start > D::default() {
3779                    while let Some(region) = cursor.region() {
3780                        if region.is_main_buffer
3781                            && (region.buffer_range.end >= metadata_buffer_range.start
3782                                || cursor.is_at_end_of_excerpt())
3783                        {
3784                            break;
3785                        }
3786                        cursor.next();
3787                    }
3788                }
3789                let start_region = cursor.region()?;
3790                while let Some(region) = cursor.region() {
3791                    if region.is_main_buffer
3792                        && (region.buffer_range.end > metadata_buffer_range.end
3793                            || cursor.is_at_end_of_excerpt())
3794                    {
3795                        break;
3796                    }
3797                    cursor.next();
3798                }
3799                let end_region = cursor.region();
3800
3801                // Convert the metadata item's range into multibuffer coordinates.
3802                let mut start_position = start_region.range.start;
3803                let region_buffer_start = start_region.buffer_range.start;
3804                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3805                {
3806                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3807                    start_position = start_position.min(start_region.range.end);
3808                }
3809
3810                let mut end_position = max_position;
3811                if let Some(end_region) = &end_region {
3812                    end_position = end_region.range.start;
3813                    debug_assert!(end_region.is_main_buffer);
3814                    let region_buffer_start = end_region.buffer_range.start;
3815                    if metadata_buffer_range.end > region_buffer_start {
3816                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3817                    }
3818                    end_position = end_position.min(end_region.range.end);
3819                }
3820
3821                if start_position <= query_range.end && end_position >= query_range.start {
3822                    return Some((start_position..end_position, metadata, excerpt));
3823                }
3824            }
3825            // When there are no more metadata items for this excerpt, move to the next excerpt.
3826            else {
3827                current_excerpt_metadata.take();
3828                cursor.next_excerpt();
3829            }
3830        })
3831    }
3832
3833    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3834        let offset = position.to_offset(self);
3835
3836        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3837        cursor.seek(&DimensionPair {
3838            key: offset,
3839            value: None,
3840        });
3841        cursor.seek_to_start_of_current_excerpt();
3842        let excerpt = cursor.excerpt()?;
3843
3844        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3845        let current_position = self
3846            .anchor_before(offset)
3847            .text_anchor
3848            .to_offset(&excerpt.buffer);
3849        let excerpt_end = excerpt
3850            .buffer
3851            .anchor_before(excerpt_end.min(current_position));
3852
3853        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3854            for hunk in diff.hunks_intersecting_range_rev(
3855                excerpt.range.context.start..excerpt_end,
3856                &excerpt.buffer,
3857            ) {
3858                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3859                if hunk_end >= current_position {
3860                    continue;
3861                }
3862                let start =
3863                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3864                        .to_point(&self);
3865                return Some(MultiBufferRow(start.row));
3866            }
3867        }
3868
3869        loop {
3870            cursor.prev_excerpt();
3871            let excerpt = cursor.excerpt()?;
3872
3873            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3874                continue;
3875            };
3876            let mut hunks =
3877                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3878            let Some(hunk) = hunks.next() else {
3879                continue;
3880            };
3881            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3882                .to_point(&self);
3883            return Some(MultiBufferRow(start.row));
3884        }
3885    }
3886
3887    pub fn has_diff_hunks(&self) -> bool {
3888        self.diffs.values().any(|diff| !diff.is_empty())
3889    }
3890
3891    pub fn surrounding_word<T: ToOffset>(
3892        &self,
3893        start: T,
3894        for_completion: bool,
3895    ) -> (Range<usize>, Option<CharKind>) {
3896        let mut start = start.to_offset(self);
3897        let mut end = start;
3898        let mut next_chars = self.chars_at(start).peekable();
3899        let mut prev_chars = self.reversed_chars_at(start).peekable();
3900
3901        let classifier = self
3902            .char_classifier_at(start)
3903            .for_completion(for_completion);
3904
3905        let word_kind = cmp::max(
3906            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3907            next_chars.peek().copied().map(|c| classifier.kind(c)),
3908        );
3909
3910        for ch in prev_chars {
3911            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3912                start -= ch.len_utf8();
3913            } else {
3914                break;
3915            }
3916        }
3917
3918        for ch in next_chars {
3919            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3920                end += ch.len_utf8();
3921            } else {
3922                break;
3923            }
3924        }
3925
3926        (start..end, word_kind)
3927    }
3928
3929    pub fn is_singleton(&self) -> bool {
3930        self.singleton
3931    }
3932
3933    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3934        if self.singleton {
3935            self.excerpts
3936                .iter()
3937                .next()
3938                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3939        } else {
3940            None
3941        }
3942    }
3943
3944    pub fn len(&self) -> usize {
3945        self.diff_transforms.summary().output.len
3946    }
3947
3948    pub fn is_empty(&self) -> bool {
3949        self.excerpts.summary().text.len == 0
3950    }
3951
3952    pub fn widest_line_number(&self) -> u32 {
3953        self.excerpts.summary().widest_line_number + 1
3954    }
3955
3956    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3957        let range = range.start.to_offset(self)..range.end.to_offset(self);
3958        let mut excerpts = self.cursor::<usize>();
3959        excerpts.seek(&range.start);
3960
3961        let mut chunk;
3962        let mut has_trailing_newline;
3963        let excerpt_bytes;
3964        if let Some(region) = excerpts.region() {
3965            let mut bytes = region.buffer.bytes_in_range(
3966                region.buffer_range.start + range.start - region.range.start
3967                    ..(region.buffer_range.start + range.end - region.range.start)
3968                        .min(region.buffer_range.end),
3969            );
3970            chunk = bytes.next().unwrap_or(&[][..]);
3971            excerpt_bytes = Some(bytes);
3972            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3973            if chunk.is_empty() && has_trailing_newline {
3974                chunk = b"\n";
3975                has_trailing_newline = false;
3976            }
3977        } else {
3978            chunk = &[][..];
3979            excerpt_bytes = None;
3980            has_trailing_newline = false;
3981        };
3982
3983        MultiBufferBytes {
3984            range,
3985            cursor: excerpts,
3986            excerpt_bytes,
3987            has_trailing_newline,
3988            chunk,
3989        }
3990    }
3991
3992    pub fn reversed_bytes_in_range<T: ToOffset>(
3993        &self,
3994        range: Range<T>,
3995    ) -> ReversedMultiBufferBytes {
3996        let range = range.start.to_offset(self)..range.end.to_offset(self);
3997        let mut chunks = self.reversed_chunks_in_range(range.clone());
3998        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3999        ReversedMultiBufferBytes {
4000            range,
4001            chunks,
4002            chunk,
4003        }
4004    }
4005
4006    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4007        let mut cursor = self.cursor::<Point>();
4008        cursor.seek(&Point::new(start_row.0, 0));
4009        let mut result = MultiBufferRows {
4010            point: Point::new(0, 0),
4011            is_empty: self.excerpts.is_empty(),
4012            cursor,
4013        };
4014        result.seek(start_row);
4015        result
4016    }
4017
4018    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4019        let mut chunks = MultiBufferChunks {
4020            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4021            range: 0..0,
4022            excerpts: self.excerpts.cursor(&()),
4023            diff_transforms: self.diff_transforms.cursor(&()),
4024            diffs: &self.diffs,
4025            diff_base_chunks: None,
4026            excerpt_chunks: None,
4027            buffer_chunk: None,
4028            language_aware,
4029        };
4030        let range = range.start.to_offset(self)..range.end.to_offset(self);
4031        chunks.seek(range);
4032        chunks
4033    }
4034
4035    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4036        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4037    }
4038
4039    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4040        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4041    }
4042
4043    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4044        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4045    }
4046
4047    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4048        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4049            buffer.clip_point_utf16(Unclipped(point), bias)
4050        })
4051    }
4052
4053    pub fn offset_to_point(&self, offset: usize) -> Point {
4054        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4055    }
4056
4057    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4058        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4059    }
4060
4061    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4062        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4063    }
4064
4065    pub fn point_to_offset(&self, point: Point) -> usize {
4066        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4067    }
4068
4069    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4070        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4071    }
4072
4073    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4074        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4075    }
4076
4077    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4078        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4079    }
4080
4081    fn clip_dimension<D>(
4082        &self,
4083        position: D,
4084        bias: Bias,
4085        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4086    ) -> D
4087    where
4088        D: TextDimension + Ord + Sub<D, Output = D>,
4089    {
4090        let mut cursor = self.cursor();
4091        cursor.seek(&position);
4092        if let Some(region) = cursor.region() {
4093            if position >= region.range.end {
4094                return region.range.end;
4095            }
4096            let overshoot = position - region.range.start;
4097            let mut buffer_position = region.buffer_range.start;
4098            buffer_position.add_assign(&overshoot);
4099            let clipped_buffer_position =
4100                clip_buffer_position(&region.buffer, buffer_position, bias);
4101            let mut position = region.range.start;
4102            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4103            position
4104        } else {
4105            D::from_text_summary(&self.text_summary())
4106        }
4107    }
4108
4109    fn convert_dimension<D1, D2>(
4110        &self,
4111        key: D1,
4112        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4113    ) -> D2
4114    where
4115        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4116        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4117    {
4118        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4119        cursor.seek(&DimensionPair { key, value: None });
4120        if let Some(region) = cursor.region() {
4121            if key >= region.range.end.key {
4122                return region.range.end.value.unwrap();
4123            }
4124            let start_key = region.range.start.key;
4125            let start_value = region.range.start.value.unwrap();
4126            let buffer_start_key = region.buffer_range.start.key;
4127            let buffer_start_value = region.buffer_range.start.value.unwrap();
4128            let mut buffer_key = buffer_start_key;
4129            buffer_key.add_assign(&(key - start_key));
4130            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4131            let mut result = start_value;
4132            result.add_assign(&(buffer_value - buffer_start_value));
4133            result
4134        } else {
4135            D2::from_text_summary(&self.text_summary())
4136        }
4137    }
4138
4139    pub fn point_to_buffer_offset<T: ToOffset>(
4140        &self,
4141        point: T,
4142    ) -> Option<(&BufferSnapshot, usize)> {
4143        let offset = point.to_offset(self);
4144        let mut cursor = self.cursor::<usize>();
4145        cursor.seek(&offset);
4146        let region = cursor.region()?;
4147        let overshoot = offset - region.range.start;
4148        let buffer_offset = region.buffer_range.start + overshoot;
4149        Some((region.buffer, buffer_offset))
4150    }
4151
4152    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4153        let mut cursor = self.cursor::<Point>();
4154        cursor.seek(&point);
4155        let region = cursor.region()?;
4156        let overshoot = point - region.range.start;
4157        let buffer_offset = region.buffer_range.start + overshoot;
4158        Some((region.buffer, buffer_offset, region.is_main_buffer))
4159    }
4160
4161    pub fn suggested_indents(
4162        &self,
4163        rows: impl IntoIterator<Item = u32>,
4164        cx: &App,
4165    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4166        let mut result = BTreeMap::new();
4167
4168        let mut rows_for_excerpt = Vec::new();
4169        let mut cursor = self.cursor::<Point>();
4170        let mut rows = rows.into_iter().peekable();
4171        let mut prev_row = u32::MAX;
4172        let mut prev_language_indent_size = IndentSize::default();
4173
4174        while let Some(row) = rows.next() {
4175            cursor.seek(&Point::new(row, 0));
4176            let Some(region) = cursor.region() else {
4177                continue;
4178            };
4179
4180            // Retrieve the language and indent size once for each disjoint region being indented.
4181            let single_indent_size = if row.saturating_sub(1) == prev_row {
4182                prev_language_indent_size
4183            } else {
4184                region
4185                    .buffer
4186                    .language_indent_size_at(Point::new(row, 0), cx)
4187            };
4188            prev_language_indent_size = single_indent_size;
4189            prev_row = row;
4190
4191            let start_buffer_row = region.buffer_range.start.row;
4192            let start_multibuffer_row = region.range.start.row;
4193            let end_multibuffer_row = region.range.end.row;
4194
4195            rows_for_excerpt.push(row);
4196            while let Some(next_row) = rows.peek().copied() {
4197                if end_multibuffer_row > next_row {
4198                    rows_for_excerpt.push(next_row);
4199                    rows.next();
4200                } else {
4201                    break;
4202                }
4203            }
4204
4205            let buffer_rows = rows_for_excerpt
4206                .drain(..)
4207                .map(|row| start_buffer_row + row - start_multibuffer_row);
4208            let buffer_indents = region
4209                .buffer
4210                .suggested_indents(buffer_rows, single_indent_size);
4211            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4212                (
4213                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4214                    indent,
4215                )
4216            });
4217            result.extend(multibuffer_indents);
4218        }
4219
4220        result
4221    }
4222
4223    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4224        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4225            let mut size = buffer.indent_size_for_line(range.start.row);
4226            size.len = size
4227                .len
4228                .min(range.end.column)
4229                .saturating_sub(range.start.column);
4230            size
4231        } else {
4232            IndentSize::spaces(0)
4233        }
4234    }
4235
4236    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4237        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4238            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4239        } else {
4240            LineIndent::spaces(0)
4241        }
4242    }
4243
4244    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4245        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4246
4247        if self.language_settings(cx).extend_comment_on_newline {
4248            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4249                let delimiters = language_scope.line_comment_prefixes();
4250                for delimiter in delimiters {
4251                    if *self
4252                        .chars_at(Point::new(row.0, indent.len() as u32))
4253                        .take(delimiter.chars().count())
4254                        .collect::<String>()
4255                        .as_str()
4256                        == **delimiter
4257                    {
4258                        indent.push_str(&delimiter);
4259                        break;
4260                    }
4261                }
4262            }
4263        }
4264
4265        indent
4266    }
4267
4268    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4269    where
4270        T: ToOffset,
4271    {
4272        for char in self.reversed_chars_at(position) {
4273            if !char.is_whitespace() {
4274                return false;
4275            }
4276            if char == '\n' {
4277                return true;
4278            }
4279        }
4280        return true;
4281    }
4282
4283    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4284        while row.0 > 0 {
4285            row.0 -= 1;
4286            if !self.is_line_blank(row) {
4287                return Some(row);
4288            }
4289        }
4290        None
4291    }
4292
4293    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4294        if let Some((_, range)) = self.buffer_line_for_row(row) {
4295            range.end.column - range.start.column
4296        } else {
4297            0
4298        }
4299    }
4300
4301    pub fn buffer_line_for_row(
4302        &self,
4303        row: MultiBufferRow,
4304    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4305        let mut cursor = self.cursor::<Point>();
4306        let point = Point::new(row.0, 0);
4307        cursor.seek(&point);
4308        let region = cursor.region()?;
4309        let overshoot = point.min(region.range.end) - region.range.start;
4310        let buffer_point = region.buffer_range.start + overshoot;
4311        if buffer_point.row > region.buffer_range.end.row {
4312            return None;
4313        }
4314        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4315        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4316            .min(region.buffer_range.end);
4317        Some((region.buffer, line_start..line_end))
4318    }
4319
4320    pub fn max_point(&self) -> Point {
4321        self.text_summary().lines
4322    }
4323
4324    pub fn max_row(&self) -> MultiBufferRow {
4325        MultiBufferRow(self.text_summary().lines.row)
4326    }
4327
4328    pub fn text_summary(&self) -> TextSummary {
4329        self.diff_transforms.summary().output
4330    }
4331
4332    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4333    where
4334        D: TextDimension,
4335        O: ToOffset,
4336    {
4337        let range = range.start.to_offset(self)..range.end.to_offset(self);
4338        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4339        cursor.seek(&range.start, Bias::Right, &());
4340
4341        let Some(first_transform) = cursor.item() else {
4342            return D::from_text_summary(&TextSummary::default());
4343        };
4344
4345        let diff_transform_start = cursor.start().0;
4346        let diff_transform_end = cursor.end(&()).0;
4347        let diff_start = range.start;
4348        let start_overshoot = diff_start - diff_transform_start;
4349        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4350
4351        let mut result = match first_transform {
4352            DiffTransform::BufferContent { .. } => {
4353                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4354                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4355                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4356            }
4357            DiffTransform::DeletedHunk {
4358                buffer_id,
4359                base_text_byte_range,
4360                has_trailing_newline,
4361                ..
4362            } => {
4363                let buffer_start = base_text_byte_range.start + start_overshoot;
4364                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4365                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4366                    panic!("{:?} is in non-existent deleted hunk", range.start)
4367                };
4368
4369                let include_trailing_newline =
4370                    *has_trailing_newline && range.end >= diff_transform_end;
4371                if include_trailing_newline {
4372                    buffer_end -= 1;
4373                }
4374
4375                let mut summary =
4376                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4377
4378                if include_trailing_newline {
4379                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4380                }
4381
4382                summary
4383            }
4384        };
4385        if range.end < diff_transform_end {
4386            return result;
4387        }
4388
4389        cursor.next(&());
4390        result.add_assign(&D::from_text_summary(&cursor.summary(
4391            &range.end,
4392            Bias::Right,
4393            &(),
4394        )));
4395
4396        let Some(last_transform) = cursor.item() else {
4397            return result;
4398        };
4399
4400        let overshoot = range.end - cursor.start().0;
4401        let suffix = match last_transform {
4402            DiffTransform::BufferContent { .. } => {
4403                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4404                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4405            }
4406            DiffTransform::DeletedHunk {
4407                base_text_byte_range,
4408                buffer_id,
4409                has_trailing_newline,
4410                ..
4411            } => {
4412                let buffer_end = base_text_byte_range.start + overshoot;
4413                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) 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                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4516                        if let Some(base_text) =
4517                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4518                        {
4519                            if base_text.can_resolve(&diff_base_anchor) {
4520                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4521                                if base_text_offset >= base_text_byte_range.start
4522                                    && base_text_offset <= base_text_byte_range.end
4523                                {
4524                                    let position_in_hunk = base_text
4525                                        .text_summary_for_range::<D, _>(
4526                                            base_text_byte_range.start..base_text_offset,
4527                                        );
4528                                    position.add_assign(&position_in_hunk);
4529                                } else if at_transform_end {
4530                                    diff_transforms.next(&());
4531                                    continue;
4532                                }
4533                            }
4534                        }
4535                    }
4536                }
4537                _ => {
4538                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4539                        diff_transforms.next(&());
4540                        continue;
4541                    }
4542                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4543                    position.add_assign(&overshoot);
4544                }
4545            }
4546
4547            return position;
4548        }
4549    }
4550
4551    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4552        let mut cursor = self
4553            .excerpts
4554            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4555        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4556
4557        cursor.seek(&Some(locator), Bias::Left, &());
4558        if cursor.item().is_none() {
4559            cursor.next(&());
4560        }
4561
4562        let mut position = cursor.start().1;
4563        if let Some(excerpt) = cursor.item() {
4564            if excerpt.id == anchor.excerpt_id {
4565                let excerpt_buffer_start = excerpt
4566                    .buffer
4567                    .offset_for_anchor(&excerpt.range.context.start);
4568                let excerpt_buffer_end =
4569                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4570                let buffer_position = cmp::min(
4571                    excerpt_buffer_end,
4572                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4573                );
4574                if buffer_position > excerpt_buffer_start {
4575                    position.value += buffer_position - excerpt_buffer_start;
4576                }
4577            }
4578        }
4579        position
4580    }
4581
4582    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4583    where
4584        D: TextDimension + Ord + Sub<D, Output = D>,
4585        I: 'a + IntoIterator<Item = &'a Anchor>,
4586    {
4587        let mut anchors = anchors.into_iter().peekable();
4588        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4589        let mut diff_transforms_cursor = self
4590            .diff_transforms
4591            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4592        diff_transforms_cursor.next(&());
4593
4594        let mut summaries = Vec::new();
4595        while let Some(anchor) = anchors.peek() {
4596            let excerpt_id = anchor.excerpt_id;
4597            let excerpt_anchors = iter::from_fn(|| {
4598                let anchor = anchors.peek()?;
4599                if anchor.excerpt_id == excerpt_id {
4600                    Some(anchors.next().unwrap())
4601                } else {
4602                    None
4603                }
4604            });
4605
4606            let locator = self.excerpt_locator_for_id(excerpt_id);
4607            cursor.seek_forward(locator, Bias::Left, &());
4608            if cursor.item().is_none() {
4609                cursor.next(&());
4610            }
4611
4612            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4613            if let Some(excerpt) = cursor.item() {
4614                if excerpt.id != excerpt_id {
4615                    let position = self.resolve_summary_for_anchor(
4616                        &Anchor::min(),
4617                        excerpt_start_position,
4618                        &mut diff_transforms_cursor,
4619                    );
4620                    summaries.extend(excerpt_anchors.map(|_| position));
4621                    continue;
4622                }
4623                let excerpt_buffer_start =
4624                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4625                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4626                for (buffer_summary, anchor) in excerpt
4627                    .buffer
4628                    .summaries_for_anchors_with_payload::<D, _, _>(
4629                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4630                    )
4631                {
4632                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4633                    let mut position = excerpt_start_position;
4634                    if summary > excerpt_buffer_start {
4635                        position.add_assign(&(summary - excerpt_buffer_start));
4636                    }
4637
4638                    if position > diff_transforms_cursor.start().0 .0 {
4639                        diff_transforms_cursor.seek_forward(
4640                            &ExcerptDimension(position),
4641                            Bias::Left,
4642                            &(),
4643                        );
4644                    }
4645
4646                    summaries.push(self.resolve_summary_for_anchor(
4647                        anchor,
4648                        position,
4649                        &mut diff_transforms_cursor,
4650                    ));
4651                }
4652            } else {
4653                diff_transforms_cursor.seek_forward(
4654                    &ExcerptDimension(excerpt_start_position),
4655                    Bias::Left,
4656                    &(),
4657                );
4658                let position = self.resolve_summary_for_anchor(
4659                    &Anchor::max(),
4660                    excerpt_start_position,
4661                    &mut diff_transforms_cursor,
4662                );
4663                summaries.extend(excerpt_anchors.map(|_| position));
4664            }
4665        }
4666
4667        summaries
4668    }
4669
4670    pub fn dimensions_from_points<'a, D>(
4671        &'a self,
4672        points: impl 'a + IntoIterator<Item = Point>,
4673    ) -> impl 'a + Iterator<Item = D>
4674    where
4675        D: TextDimension + Sub<D, Output = D>,
4676    {
4677        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4678        cursor.seek(&DimensionPair {
4679            key: Point::default(),
4680            value: None,
4681        });
4682        let mut points = points.into_iter();
4683        iter::from_fn(move || {
4684            let point = points.next()?;
4685
4686            cursor.seek_forward(&DimensionPair {
4687                key: point,
4688                value: None,
4689            });
4690
4691            if let Some(region) = cursor.region() {
4692                let overshoot = point - region.range.start.key;
4693                let buffer_point = region.buffer_range.start.key + overshoot;
4694                let mut position = region.range.start.value.unwrap();
4695                position.add_assign(
4696                    &region
4697                        .buffer
4698                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4699                );
4700                return Some(position);
4701            } else {
4702                return Some(D::from_text_summary(&self.text_summary()));
4703            }
4704        })
4705    }
4706
4707    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4708    where
4709        I: 'a + IntoIterator<Item = &'a Anchor>,
4710    {
4711        let mut anchors = anchors.into_iter().enumerate().peekable();
4712        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4713        cursor.next(&());
4714
4715        let mut result = Vec::new();
4716
4717        while let Some((_, anchor)) = anchors.peek() {
4718            let old_excerpt_id = anchor.excerpt_id;
4719
4720            // Find the location where this anchor's excerpt should be.
4721            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4722            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4723
4724            if cursor.item().is_none() {
4725                cursor.next(&());
4726            }
4727
4728            let next_excerpt = cursor.item();
4729            let prev_excerpt = cursor.prev_item();
4730
4731            // Process all of the anchors for this excerpt.
4732            while let Some((_, anchor)) = anchors.peek() {
4733                if anchor.excerpt_id != old_excerpt_id {
4734                    break;
4735                }
4736                let (anchor_ix, anchor) = anchors.next().unwrap();
4737                let mut anchor = *anchor;
4738
4739                // Leave min and max anchors unchanged if invalid or
4740                // if the old excerpt still exists at this location
4741                let mut kept_position = next_excerpt
4742                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4743                    || old_excerpt_id == ExcerptId::max()
4744                    || old_excerpt_id == ExcerptId::min();
4745
4746                // If the old excerpt no longer exists at this location, then attempt to
4747                // find an equivalent position for this anchor in an adjacent excerpt.
4748                if !kept_position {
4749                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4750                        if excerpt.contains(&anchor) {
4751                            anchor.excerpt_id = excerpt.id;
4752                            kept_position = true;
4753                            break;
4754                        }
4755                    }
4756                }
4757
4758                // If there's no adjacent excerpt that contains the anchor's position,
4759                // then report that the anchor has lost its position.
4760                if !kept_position {
4761                    anchor = if let Some(excerpt) = next_excerpt {
4762                        let mut text_anchor = excerpt
4763                            .range
4764                            .context
4765                            .start
4766                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4767                        if text_anchor
4768                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4769                            .is_gt()
4770                        {
4771                            text_anchor = excerpt.range.context.end;
4772                        }
4773                        Anchor {
4774                            buffer_id: Some(excerpt.buffer_id),
4775                            excerpt_id: excerpt.id,
4776                            text_anchor,
4777                            diff_base_anchor: None,
4778                        }
4779                    } else if let Some(excerpt) = prev_excerpt {
4780                        let mut text_anchor = excerpt
4781                            .range
4782                            .context
4783                            .end
4784                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4785                        if text_anchor
4786                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4787                            .is_lt()
4788                        {
4789                            text_anchor = excerpt.range.context.start;
4790                        }
4791                        Anchor {
4792                            buffer_id: Some(excerpt.buffer_id),
4793                            excerpt_id: excerpt.id,
4794                            text_anchor,
4795                            diff_base_anchor: None,
4796                        }
4797                    } else if anchor.text_anchor.bias == Bias::Left {
4798                        Anchor::min()
4799                    } else {
4800                        Anchor::max()
4801                    };
4802                }
4803
4804                result.push((anchor_ix, anchor, kept_position));
4805            }
4806        }
4807        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4808        result
4809    }
4810
4811    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4812        self.anchor_at(position, Bias::Left)
4813    }
4814
4815    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4816        self.anchor_at(position, Bias::Right)
4817    }
4818
4819    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4820        let offset = position.to_offset(self);
4821
4822        // Find the given position in the diff transforms. Determine the corresponding
4823        // offset in the excerpts, and whether the position is within a deleted hunk.
4824        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4825        diff_transforms.seek(&offset, Bias::Right, &());
4826
4827        if offset == diff_transforms.start().0 && bias == Bias::Left {
4828            if let Some(prev_item) = diff_transforms.prev_item() {
4829                match prev_item {
4830                    DiffTransform::DeletedHunk { .. } => {
4831                        diff_transforms.prev(&());
4832                    }
4833                    _ => {}
4834                }
4835            }
4836        }
4837        let offset_in_transform = offset - diff_transforms.start().0;
4838        let mut excerpt_offset = diff_transforms.start().1;
4839        let mut diff_base_anchor = None;
4840        if let Some(DiffTransform::DeletedHunk {
4841            buffer_id,
4842            base_text_byte_range,
4843            has_trailing_newline,
4844            ..
4845        }) = diff_transforms.item()
4846        {
4847            let diff = self.diffs.get(buffer_id).expect("missing diff");
4848            if offset_in_transform > base_text_byte_range.len() {
4849                debug_assert!(*has_trailing_newline);
4850                bias = Bias::Right;
4851            } else {
4852                diff_base_anchor = Some(
4853                    diff.base_text()
4854                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4855                );
4856                bias = Bias::Left;
4857            }
4858        } else {
4859            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4860        };
4861
4862        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4863            return Anchor {
4864                buffer_id: Some(buffer_id),
4865                excerpt_id: *excerpt_id,
4866                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4867                diff_base_anchor,
4868            };
4869        }
4870
4871        let mut excerpts = self
4872            .excerpts
4873            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4874        excerpts.seek(&excerpt_offset, Bias::Right, &());
4875        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4876            excerpts.prev(&());
4877        }
4878        if let Some(excerpt) = excerpts.item() {
4879            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4880            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4881                overshoot -= 1;
4882                bias = Bias::Right;
4883            }
4884
4885            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4886            let text_anchor =
4887                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4888            Anchor {
4889                buffer_id: Some(excerpt.buffer_id),
4890                excerpt_id: excerpt.id,
4891                text_anchor,
4892                diff_base_anchor,
4893            }
4894        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4895            Anchor::min()
4896        } else {
4897            Anchor::max()
4898        }
4899    }
4900
4901    /// Returns an anchor for the given excerpt and text anchor,
4902    /// returns None if the excerpt_id is no longer valid.
4903    pub fn anchor_in_excerpt(
4904        &self,
4905        excerpt_id: ExcerptId,
4906        text_anchor: text::Anchor,
4907    ) -> Option<Anchor> {
4908        let locator = self.excerpt_locator_for_id(excerpt_id);
4909        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4910        cursor.seek(locator, Bias::Left, &());
4911        if let Some(excerpt) = cursor.item() {
4912            if excerpt.id == excerpt_id {
4913                let text_anchor = excerpt.clip_anchor(text_anchor);
4914                drop(cursor);
4915                return Some(Anchor {
4916                    buffer_id: Some(excerpt.buffer_id),
4917                    excerpt_id,
4918                    text_anchor,
4919                    diff_base_anchor: None,
4920                });
4921            }
4922        }
4923        None
4924    }
4925
4926    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4927        Some(self.excerpt(excerpt_id)?.range.context.clone())
4928    }
4929
4930    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4931        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4932            true
4933        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4934            excerpt.buffer.can_resolve(&anchor.text_anchor)
4935        } else {
4936            false
4937        }
4938    }
4939
4940    pub fn excerpts(
4941        &self,
4942    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4943        self.excerpts
4944            .iter()
4945            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4946    }
4947
4948    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4949        let excerpts = self.excerpts.cursor(&());
4950        let diff_transforms = self.diff_transforms.cursor(&());
4951        MultiBufferCursor {
4952            excerpts,
4953            diff_transforms,
4954            diffs: &self.diffs,
4955            cached_region: None,
4956        }
4957    }
4958
4959    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4960        let start_locator = self.excerpt_locator_for_id(id);
4961        let mut excerpts = self
4962            .excerpts
4963            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4964        excerpts.seek(&Some(start_locator), Bias::Left, &());
4965        excerpts.prev(&());
4966
4967        let mut diff_transforms = self
4968            .diff_transforms
4969            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4970        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4971        if diff_transforms.end(&()).1 < excerpts.start().1 {
4972            diff_transforms.next(&());
4973        }
4974
4975        let excerpt = excerpts.item()?;
4976        Some(MultiBufferExcerpt {
4977            excerpt,
4978            offset: diff_transforms.start().0 .0,
4979            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4980            excerpt_offset: excerpts.start().1.clone(),
4981            diff_transforms,
4982        })
4983    }
4984
4985    pub fn excerpt_boundaries_in_range<R, T>(
4986        &self,
4987        range: R,
4988    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4989    where
4990        R: RangeBounds<T>,
4991        T: ToOffset,
4992    {
4993        let start_offset;
4994        let start = match range.start_bound() {
4995            Bound::Included(start) => {
4996                start_offset = start.to_offset(self);
4997                Bound::Included(start_offset)
4998            }
4999            Bound::Excluded(_) => {
5000                panic!("not supported")
5001            }
5002            Bound::Unbounded => {
5003                start_offset = 0;
5004                Bound::Unbounded
5005            }
5006        };
5007        let end = match range.end_bound() {
5008            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5009            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5010            Bound::Unbounded => Bound::Unbounded,
5011        };
5012        let bounds = (start, end);
5013
5014        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5015        cursor.seek(&DimensionPair {
5016            key: start_offset,
5017            value: None,
5018        });
5019
5020        if cursor
5021            .region()
5022            .is_some_and(|region| bounds.contains(&region.range.start.key))
5023        {
5024            cursor.prev_excerpt();
5025        } else {
5026            cursor.seek_to_start_of_current_excerpt();
5027        }
5028        let mut prev_region = cursor.region();
5029
5030        cursor.next_excerpt();
5031
5032        let mut visited_end = false;
5033        iter::from_fn(move || loop {
5034            if self.singleton {
5035                return None;
5036            }
5037
5038            let next_region = cursor.region();
5039            cursor.next_excerpt();
5040
5041            let next_region_start = if let Some(region) = &next_region {
5042                if !bounds.contains(&region.range.start.key) {
5043                    prev_region = next_region;
5044                    continue;
5045                }
5046                region.range.start.value.unwrap()
5047            } else {
5048                if !bounds.contains(&self.len()) {
5049                    return None;
5050                }
5051                self.max_point()
5052            };
5053            let next_region_end = if let Some(region) = cursor.region() {
5054                region.range.start.value.unwrap()
5055            } else {
5056                self.max_point()
5057            };
5058
5059            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5060                id: region.excerpt.id,
5061                buffer: region.excerpt.buffer.clone(),
5062                buffer_id: region.excerpt.buffer_id,
5063                range: region.excerpt.range.clone(),
5064                end_row: MultiBufferRow(next_region_start.row),
5065            });
5066
5067            let next = next_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: if region.excerpt.has_trailing_newline {
5073                    MultiBufferRow(next_region_end.row - 1)
5074                } else {
5075                    MultiBufferRow(next_region_end.row)
5076                },
5077            });
5078
5079            if next.is_none() {
5080                if visited_end {
5081                    return None;
5082                } else {
5083                    visited_end = true;
5084                }
5085            }
5086
5087            let row = MultiBufferRow(next_region_start.row);
5088
5089            prev_region = next_region;
5090
5091            return Some(ExcerptBoundary { row, prev, next });
5092        })
5093    }
5094
5095    pub fn edit_count(&self) -> usize {
5096        self.edit_count
5097    }
5098
5099    pub fn non_text_state_update_count(&self) -> usize {
5100        self.non_text_state_update_count
5101    }
5102
5103    /// Returns the smallest enclosing bracket ranges containing the given range or
5104    /// None if no brackets contain range or the range is not contained in a single
5105    /// excerpt
5106    ///
5107    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5108    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5109        &self,
5110        range: Range<T>,
5111        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5112    ) -> Option<(Range<usize>, Range<usize>)> {
5113        let range = range.start.to_offset(self)..range.end.to_offset(self);
5114        let mut excerpt = self.excerpt_containing(range.clone())?;
5115        let buffer = excerpt.buffer();
5116        let excerpt_buffer_range = excerpt.buffer_range();
5117
5118        // Filter to ranges contained in the excerpt
5119        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5120            excerpt_buffer_range.contains(&open.start)
5121                && excerpt_buffer_range.contains(&close.end)
5122                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5123        };
5124
5125        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5126            excerpt.map_range_to_buffer(range),
5127            Some(&range_filter),
5128        )?;
5129
5130        Some((
5131            excerpt.map_range_from_buffer(open),
5132            excerpt.map_range_from_buffer(close),
5133        ))
5134    }
5135
5136    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5137    /// not contained in a single excerpt
5138    pub fn enclosing_bracket_ranges<T: ToOffset>(
5139        &self,
5140        range: Range<T>,
5141    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5142        let range = range.start.to_offset(self)..range.end.to_offset(self);
5143        let mut excerpt = self.excerpt_containing(range.clone())?;
5144
5145        Some(
5146            excerpt
5147                .buffer()
5148                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5149                .filter_map(move |pair| {
5150                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5151                        Some((
5152                            excerpt.map_range_from_buffer(pair.open_range),
5153                            excerpt.map_range_from_buffer(pair.close_range),
5154                        ))
5155                    } else {
5156                        None
5157                    }
5158                }),
5159        )
5160    }
5161
5162    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5163    /// not contained in a single excerpt
5164    pub fn text_object_ranges<T: ToOffset>(
5165        &self,
5166        range: Range<T>,
5167        options: TreeSitterOptions,
5168    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5169        let range = range.start.to_offset(self)..range.end.to_offset(self);
5170        self.excerpt_containing(range.clone())
5171            .map(|mut excerpt| {
5172                excerpt
5173                    .buffer()
5174                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5175                    .filter_map(move |(range, text_object)| {
5176                        if excerpt.contains_buffer_range(range.clone()) {
5177                            Some((excerpt.map_range_from_buffer(range), text_object))
5178                        } else {
5179                            None
5180                        }
5181                    })
5182            })
5183            .into_iter()
5184            .flatten()
5185    }
5186
5187    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5188    /// not contained in a single excerpt
5189    pub fn bracket_ranges<T: ToOffset>(
5190        &self,
5191        range: Range<T>,
5192    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5193        let range = range.start.to_offset(self)..range.end.to_offset(self);
5194        let mut excerpt = self.excerpt_containing(range.clone())?;
5195
5196        Some(
5197            excerpt
5198                .buffer()
5199                .bracket_ranges(excerpt.map_range_to_buffer(range))
5200                .filter_map(move |pair| {
5201                    let buffer_range = pair.open_range.start..pair.close_range.end;
5202                    if excerpt.contains_buffer_range(buffer_range) {
5203                        Some((
5204                            excerpt.map_range_from_buffer(pair.open_range),
5205                            excerpt.map_range_from_buffer(pair.close_range),
5206                        ))
5207                    } else {
5208                        None
5209                    }
5210                }),
5211        )
5212    }
5213
5214    pub fn redacted_ranges<'a, T: ToOffset>(
5215        &'a self,
5216        range: Range<T>,
5217        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5218    ) -> impl Iterator<Item = Range<usize>> + 'a {
5219        let range = range.start.to_offset(self)..range.end.to_offset(self);
5220        self.lift_buffer_metadata(range, move |buffer, range| {
5221            if redaction_enabled(buffer.file()) {
5222                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5223            } else {
5224                None
5225            }
5226        })
5227        .map(|(range, _, _)| range)
5228    }
5229
5230    pub fn runnable_ranges(
5231        &self,
5232        range: Range<Anchor>,
5233    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5234        let range = range.start.to_offset(self)..range.end.to_offset(self);
5235        self.lift_buffer_metadata(range, move |buffer, range| {
5236            Some(
5237                buffer
5238                    .runnable_ranges(range.clone())
5239                    .filter(move |runnable| {
5240                        runnable.run_range.start >= range.start
5241                            && runnable.run_range.end < range.end
5242                    })
5243                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5244            )
5245        })
5246        .map(|(run_range, runnable, _)| language::RunnableRange {
5247            run_range,
5248            ..runnable
5249        })
5250    }
5251
5252    pub fn line_indents(
5253        &self,
5254        start_row: MultiBufferRow,
5255        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5256    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5257        let max_point = self.max_point();
5258        let mut cursor = self.cursor::<Point>();
5259        cursor.seek(&Point::new(start_row.0, 0));
5260        iter::from_fn(move || {
5261            let mut region = cursor.region()?;
5262            while !buffer_filter(&region.excerpt.buffer) {
5263                cursor.next();
5264                region = cursor.region()?;
5265            }
5266            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5267            let buffer_start_row =
5268                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5269
5270            let buffer_end_row = if region.is_main_buffer
5271                && (region.has_trailing_newline || region.range.end == max_point)
5272            {
5273                region.buffer_range.end.row
5274            } else {
5275                region.buffer_range.end.row.saturating_sub(1)
5276            };
5277
5278            let line_indents = region
5279                .buffer
5280                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5281            cursor.next();
5282            return Some(line_indents.map(move |(buffer_row, indent)| {
5283                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5284                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5285            }));
5286        })
5287        .flatten()
5288    }
5289
5290    pub fn reversed_line_indents(
5291        &self,
5292        end_row: MultiBufferRow,
5293        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5294    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5295        let max_point = self.max_point();
5296        let mut cursor = self.cursor::<Point>();
5297        cursor.seek(&Point::new(end_row.0, 0));
5298        iter::from_fn(move || {
5299            let mut region = cursor.region()?;
5300            while !buffer_filter(&region.excerpt.buffer) {
5301                cursor.prev();
5302                region = cursor.region()?;
5303            }
5304
5305            let buffer_start_row = region.buffer_range.start.row;
5306            let buffer_end_row = if region.is_main_buffer
5307                && (region.has_trailing_newline || region.range.end == max_point)
5308            {
5309                region.buffer_range.end.row + 1
5310            } else {
5311                region.buffer_range.end.row
5312            };
5313
5314            let overshoot = end_row.0 - region.range.start.row;
5315            let buffer_end_row =
5316                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5317
5318            let line_indents = region
5319                .buffer
5320                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5321            cursor.prev();
5322            return Some(line_indents.map(move |(buffer_row, indent)| {
5323                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5324                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5325            }));
5326        })
5327        .flatten()
5328    }
5329
5330    pub async fn enclosing_indent(
5331        &self,
5332        mut target_row: MultiBufferRow,
5333    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5334        let max_row = MultiBufferRow(self.max_point().row);
5335        if target_row >= max_row {
5336            return None;
5337        }
5338
5339        let mut target_indent = self.line_indent_for_row(target_row);
5340
5341        // If the current row is at the start of an indented block, we want to return this
5342        // block as the enclosing indent.
5343        if !target_indent.is_line_empty() && target_row < max_row {
5344            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5345            if !next_line_indent.is_line_empty()
5346                && target_indent.raw_len() < next_line_indent.raw_len()
5347            {
5348                target_indent = next_line_indent;
5349                target_row.0 += 1;
5350            }
5351        }
5352
5353        const SEARCH_ROW_LIMIT: u32 = 25000;
5354        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5355        const YIELD_INTERVAL: u32 = 100;
5356
5357        let mut accessed_row_counter = 0;
5358
5359        // If there is a blank line at the current row, search for the next non indented lines
5360        if target_indent.is_line_empty() {
5361            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5362            let end =
5363                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5364
5365            let mut non_empty_line_above = None;
5366            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5367                if row < start {
5368                    break;
5369                }
5370                accessed_row_counter += 1;
5371                if accessed_row_counter == YIELD_INTERVAL {
5372                    accessed_row_counter = 0;
5373                    yield_now().await;
5374                }
5375                if !indent.is_line_empty() {
5376                    non_empty_line_above = Some((row, indent));
5377                    break;
5378                }
5379            }
5380
5381            let mut non_empty_line_below = None;
5382            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5383                if row > end {
5384                    break;
5385                }
5386                accessed_row_counter += 1;
5387                if accessed_row_counter == YIELD_INTERVAL {
5388                    accessed_row_counter = 0;
5389                    yield_now().await;
5390                }
5391                if !indent.is_line_empty() {
5392                    non_empty_line_below = Some((row, indent));
5393                    break;
5394                }
5395            }
5396
5397            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5398                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5399                    if above_indent.raw_len() >= below_indent.raw_len() {
5400                        (above_row, above_indent)
5401                    } else {
5402                        (below_row, below_indent)
5403                    }
5404                }
5405                (Some(above), None) => above,
5406                (None, Some(below)) => below,
5407                _ => return None,
5408            };
5409
5410            target_indent = indent;
5411            target_row = row;
5412        }
5413
5414        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5415        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5416
5417        let mut start_indent = None;
5418        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5419            if row < start {
5420                break;
5421            }
5422            accessed_row_counter += 1;
5423            if accessed_row_counter == YIELD_INTERVAL {
5424                accessed_row_counter = 0;
5425                yield_now().await;
5426            }
5427            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5428                start_indent = Some((row, indent));
5429                break;
5430            }
5431        }
5432        let (start_row, start_indent_size) = start_indent?;
5433
5434        let mut end_indent = (end, None);
5435        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5436            if row > end {
5437                break;
5438            }
5439            accessed_row_counter += 1;
5440            if accessed_row_counter == YIELD_INTERVAL {
5441                accessed_row_counter = 0;
5442                yield_now().await;
5443            }
5444            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5445                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5446                break;
5447            }
5448        }
5449        let (end_row, end_indent_size) = end_indent;
5450
5451        let indent = if let Some(end_indent_size) = end_indent_size {
5452            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5453                start_indent_size
5454            } else {
5455                end_indent_size
5456            }
5457        } else {
5458            start_indent_size
5459        };
5460
5461        Some((start_row..end_row, indent))
5462    }
5463
5464    pub fn indent_guides_in_range<T: ToPoint>(
5465        &self,
5466        range: Range<T>,
5467        ignore_disabled_for_language: bool,
5468        cx: &App,
5469    ) -> impl Iterator<Item = IndentGuide> {
5470        let range = range.start.to_point(self)..range.end.to_point(self);
5471        let start_row = MultiBufferRow(range.start.row);
5472        let end_row = MultiBufferRow(range.end.row);
5473
5474        let mut row_indents = self.line_indents(start_row, |buffer| {
5475            let settings =
5476                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5477            settings.indent_guides.enabled || ignore_disabled_for_language
5478        });
5479
5480        let mut result = Vec::new();
5481        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5482
5483        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5484            if first_row > end_row {
5485                break;
5486            }
5487            let current_depth = indent_stack.len() as u32;
5488
5489            let settings =
5490                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5491            let tab_size = settings.tab_size.get() as u32;
5492
5493            // When encountering empty, continue until found useful line indent
5494            // then add to the indent stack with the depth found
5495            let mut found_indent = false;
5496            let mut last_row = first_row;
5497            if line_indent.is_line_empty() {
5498                while !found_indent {
5499                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5500                        break;
5501                    };
5502                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5503                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5504                        break;
5505                    }
5506
5507                    if new_line_indent.is_line_empty() {
5508                        continue;
5509                    }
5510                    last_row = target_row.min(end_row);
5511                    line_indent = new_line_indent;
5512                    found_indent = true;
5513                    break;
5514                }
5515            } else {
5516                found_indent = true
5517            }
5518
5519            let depth = if found_indent {
5520                line_indent.len(tab_size) / tab_size
5521                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5522            } else {
5523                current_depth
5524            };
5525
5526            match depth.cmp(&current_depth) {
5527                cmp::Ordering::Less => {
5528                    for _ in 0..(current_depth - depth) {
5529                        let mut indent = indent_stack.pop().unwrap();
5530                        if last_row != first_row {
5531                            // In this case, we landed on an empty row, had to seek forward,
5532                            // and discovered that the indent we where on is ending.
5533                            // This means that the last display row must
5534                            // be on line that ends this indent range, so we
5535                            // should display the range up to the first non-empty line
5536                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5537                        }
5538
5539                        result.push(indent)
5540                    }
5541                }
5542                cmp::Ordering::Greater => {
5543                    for next_depth in current_depth..depth {
5544                        indent_stack.push(IndentGuide {
5545                            buffer_id: buffer.remote_id(),
5546                            start_row: first_row,
5547                            end_row: last_row,
5548                            depth: next_depth,
5549                            tab_size,
5550                            settings: settings.indent_guides,
5551                        });
5552                    }
5553                }
5554                _ => {}
5555            }
5556
5557            for indent in indent_stack.iter_mut() {
5558                indent.end_row = last_row;
5559            }
5560        }
5561
5562        result.extend(indent_stack);
5563        result.into_iter()
5564    }
5565
5566    pub fn trailing_excerpt_update_count(&self) -> usize {
5567        self.trailing_excerpt_update_count
5568    }
5569
5570    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5571        self.point_to_buffer_offset(point)
5572            .and_then(|(buffer, _)| buffer.file())
5573    }
5574
5575    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5576        self.point_to_buffer_offset(point)
5577            .and_then(|(buffer, offset)| buffer.language_at(offset))
5578    }
5579
5580    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5581        self.excerpts
5582            .first()
5583            .map(|excerpt| &excerpt.buffer)
5584            .map(|buffer| {
5585                language_settings(
5586                    buffer.language().map(|language| language.name()),
5587                    buffer.file(),
5588                    cx,
5589                )
5590            })
5591            .unwrap_or_else(move || self.language_settings_at(0, cx))
5592    }
5593
5594    pub fn language_settings_at<'a, T: ToOffset>(
5595        &'a self,
5596        point: T,
5597        cx: &'a App,
5598    ) -> Cow<'a, LanguageSettings> {
5599        let mut language = None;
5600        let mut file = None;
5601        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5602            language = buffer.language_at(offset);
5603            file = buffer.file();
5604        }
5605        language_settings(language.map(|l| l.name()), file, cx)
5606    }
5607
5608    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5609        self.point_to_buffer_offset(point)
5610            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5611    }
5612
5613    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5614        self.point_to_buffer_offset(point)
5615            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5616            .unwrap_or_default()
5617    }
5618
5619    pub fn language_indent_size_at<T: ToOffset>(
5620        &self,
5621        position: T,
5622        cx: &App,
5623    ) -> Option<IndentSize> {
5624        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5625        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5626    }
5627
5628    pub fn is_dirty(&self) -> bool {
5629        self.is_dirty
5630    }
5631
5632    pub fn has_deleted_file(&self) -> bool {
5633        self.has_deleted_file
5634    }
5635
5636    pub fn has_conflict(&self) -> bool {
5637        self.has_conflict
5638    }
5639
5640    pub fn has_diagnostics(&self) -> bool {
5641        self.excerpts
5642            .iter()
5643            .any(|excerpt| excerpt.buffer.has_diagnostics())
5644    }
5645
5646    pub fn diagnostic_group(
5647        &self,
5648        buffer_id: BufferId,
5649        group_id: usize,
5650    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5651        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5652            if buffer.remote_id() != buffer_id {
5653                return None;
5654            };
5655            Some(
5656                buffer
5657                    .diagnostic_group(group_id)
5658                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5659            )
5660        })
5661        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5662    }
5663
5664    pub fn diagnostics_in_range<'a, T>(
5665        &'a self,
5666        range: Range<T>,
5667    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5668    where
5669        T: 'a
5670            + text::ToOffset
5671            + text::FromAnchor
5672            + TextDimension
5673            + Ord
5674            + Sub<T, Output = T>
5675            + fmt::Debug,
5676    {
5677        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5678            Some(
5679                buffer
5680                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5681                    .map(|entry| (entry.range, entry.diagnostic)),
5682            )
5683        })
5684        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5685    }
5686
5687    pub fn syntax_ancestor<T: ToOffset>(
5688        &self,
5689        range: Range<T>,
5690    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5691        let range = range.start.to_offset(self)..range.end.to_offset(self);
5692        let mut excerpt = self.excerpt_containing(range.clone())?;
5693        let node = excerpt
5694            .buffer()
5695            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5696        let node_range = node.byte_range();
5697        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5698            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5699        } else {
5700            MultiOrSingleBufferOffsetRange::Single(node_range)
5701        };
5702        Some((node, range))
5703    }
5704
5705    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5706        let (excerpt_id, _, buffer) = self.as_singleton()?;
5707        let outline = buffer.outline(theme)?;
5708        Some(Outline::new(
5709            outline
5710                .items
5711                .into_iter()
5712                .flat_map(|item| {
5713                    Some(OutlineItem {
5714                        depth: item.depth,
5715                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5716                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5717                        text: item.text,
5718                        highlight_ranges: item.highlight_ranges,
5719                        name_ranges: item.name_ranges,
5720                        body_range: item.body_range.and_then(|body_range| {
5721                            Some(
5722                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5723                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5724                            )
5725                        }),
5726                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5727                            Some(
5728                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5729                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5730                            )
5731                        }),
5732                    })
5733                })
5734                .collect(),
5735        ))
5736    }
5737
5738    pub fn symbols_containing<T: ToOffset>(
5739        &self,
5740        offset: T,
5741        theme: Option<&SyntaxTheme>,
5742    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5743        let anchor = self.anchor_before(offset);
5744        let excerpt_id = anchor.excerpt_id;
5745        let excerpt = self.excerpt(excerpt_id)?;
5746        Some((
5747            excerpt.buffer_id,
5748            excerpt
5749                .buffer
5750                .symbols_containing(anchor.text_anchor, theme)
5751                .into_iter()
5752                .flatten()
5753                .flat_map(|item| {
5754                    Some(OutlineItem {
5755                        depth: item.depth,
5756                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5757                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5758                        text: item.text,
5759                        highlight_ranges: item.highlight_ranges,
5760                        name_ranges: item.name_ranges,
5761                        body_range: item.body_range.and_then(|body_range| {
5762                            Some(
5763                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5764                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5765                            )
5766                        }),
5767                        annotation_range: item.annotation_range.and_then(|body_range| {
5768                            Some(
5769                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5770                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5771                            )
5772                        }),
5773                    })
5774                })
5775                .collect(),
5776        ))
5777    }
5778
5779    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5780        if id == ExcerptId::min() {
5781            Locator::min_ref()
5782        } else if id == ExcerptId::max() {
5783            Locator::max_ref()
5784        } else {
5785            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5786            cursor.seek(&id, Bias::Left, &());
5787            if let Some(entry) = cursor.item() {
5788                if entry.id == id {
5789                    return &entry.locator;
5790                }
5791            }
5792            panic!("invalid excerpt id {:?}", id)
5793        }
5794    }
5795
5796    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5797    fn excerpt_locators_for_ids(
5798        &self,
5799        ids: impl IntoIterator<Item = ExcerptId>,
5800    ) -> SmallVec<[Locator; 1]> {
5801        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5802        sorted_ids.sort_unstable();
5803        let mut locators = SmallVec::new();
5804
5805        while sorted_ids.last() == Some(&ExcerptId::max()) {
5806            sorted_ids.pop();
5807            if let Some(mapping) = self.excerpt_ids.last() {
5808                locators.push(mapping.locator.clone());
5809            }
5810        }
5811
5812        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5813        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5814            sorted_ids.next();
5815            if let Some(mapping) = self.excerpt_ids.first() {
5816                locators.push(mapping.locator.clone());
5817            }
5818        }
5819
5820        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5821        for id in sorted_ids {
5822            if cursor.seek_forward(&id, Bias::Left, &()) {
5823                locators.push(cursor.item().unwrap().locator.clone());
5824            } else {
5825                panic!("invalid excerpt id {:?}", id);
5826            }
5827        }
5828
5829        locators.sort_unstable();
5830        locators
5831    }
5832
5833    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5834        Some(self.excerpt(excerpt_id)?.buffer_id)
5835    }
5836
5837    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5838        Some(&self.excerpt(excerpt_id)?.buffer)
5839    }
5840
5841    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5842        let mut cursor = self
5843            .excerpts
5844            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5845        let locator = self.excerpt_locator_for_id(excerpt_id);
5846        if cursor.seek(&Some(locator), Bias::Left, &()) {
5847            let start = cursor.start().1.clone();
5848            let end = cursor.end(&()).1;
5849            let mut diff_transforms = self
5850                .diff_transforms
5851                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5852            diff_transforms.seek(&start, Bias::Left, &());
5853            let overshoot = start.0 - diff_transforms.start().0 .0;
5854            let start = diff_transforms.start().1 .0 + overshoot;
5855            diff_transforms.seek(&end, Bias::Right, &());
5856            let overshoot = end.0 - diff_transforms.start().0 .0;
5857            let end = diff_transforms.start().1 .0 + overshoot;
5858            Some(start..end)
5859        } else {
5860            None
5861        }
5862    }
5863
5864    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5865        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5866        let locator = self.excerpt_locator_for_id(excerpt_id);
5867        if cursor.seek(&Some(locator), Bias::Left, &()) {
5868            if let Some(excerpt) = cursor.item() {
5869                return Some(excerpt.range.context.clone());
5870            }
5871        }
5872        None
5873    }
5874
5875    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5876        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5877        let locator = self.excerpt_locator_for_id(excerpt_id);
5878        cursor.seek(&Some(locator), Bias::Left, &());
5879        if let Some(excerpt) = cursor.item() {
5880            if excerpt.id == excerpt_id {
5881                return Some(excerpt);
5882            }
5883        }
5884        None
5885    }
5886
5887    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5888    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5889        let range = range.start.to_offset(self)..range.end.to_offset(self);
5890        let mut cursor = self.cursor::<usize>();
5891        cursor.seek(&range.start);
5892
5893        let start_excerpt = cursor.excerpt()?;
5894        if range.end != range.start {
5895            cursor.seek_forward(&range.end);
5896            if cursor.excerpt()?.id != start_excerpt.id {
5897                return None;
5898            }
5899        }
5900
5901        cursor.seek_to_start_of_current_excerpt();
5902        let region = cursor.region()?;
5903        let offset = region.range.start;
5904        let buffer_offset = region.buffer_range.start;
5905        let excerpt_offset = cursor.excerpts.start().clone();
5906        Some(MultiBufferExcerpt {
5907            diff_transforms: cursor.diff_transforms,
5908            excerpt: start_excerpt,
5909            offset,
5910            buffer_offset,
5911            excerpt_offset,
5912        })
5913    }
5914
5915    pub fn selections_in_range<'a>(
5916        &'a self,
5917        range: &'a Range<Anchor>,
5918        include_local: bool,
5919    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5920        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5921        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5922        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5923        cursor.seek(start_locator, Bias::Left, &());
5924        cursor
5925            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5926            .flat_map(move |excerpt| {
5927                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5928                if excerpt.id == range.start.excerpt_id {
5929                    query_range.start = range.start.text_anchor;
5930                }
5931                if excerpt.id == range.end.excerpt_id {
5932                    query_range.end = range.end.text_anchor;
5933                }
5934
5935                excerpt
5936                    .buffer
5937                    .selections_in_range(query_range, include_local)
5938                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5939                        selections.map(move |selection| {
5940                            let mut start = Anchor {
5941                                buffer_id: Some(excerpt.buffer_id),
5942                                excerpt_id: excerpt.id,
5943                                text_anchor: selection.start,
5944                                diff_base_anchor: None,
5945                            };
5946                            let mut end = Anchor {
5947                                buffer_id: Some(excerpt.buffer_id),
5948                                excerpt_id: excerpt.id,
5949                                text_anchor: selection.end,
5950                                diff_base_anchor: None,
5951                            };
5952                            if range.start.cmp(&start, self).is_gt() {
5953                                start = range.start;
5954                            }
5955                            if range.end.cmp(&end, self).is_lt() {
5956                                end = range.end;
5957                            }
5958
5959                            (
5960                                replica_id,
5961                                line_mode,
5962                                cursor_shape,
5963                                Selection {
5964                                    id: selection.id,
5965                                    start,
5966                                    end,
5967                                    reversed: selection.reversed,
5968                                    goal: selection.goal,
5969                                },
5970                            )
5971                        })
5972                    })
5973            })
5974    }
5975
5976    pub fn show_headers(&self) -> bool {
5977        self.show_headers
5978    }
5979
5980    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5981        self.diffs.get(&buffer_id)
5982    }
5983}
5984
5985#[cfg(any(test, feature = "test-support"))]
5986impl MultiBufferSnapshot {
5987    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5988        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5989        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5990        start..end
5991    }
5992
5993    #[cfg(any(test, feature = "test-support"))]
5994    fn check_invariants(&self) {
5995        let excerpts = self.excerpts.items(&());
5996        let excerpt_ids = self.excerpt_ids.items(&());
5997
5998        for (ix, excerpt) in excerpts.iter().enumerate() {
5999            if ix == 0 {
6000                if excerpt.locator <= Locator::min() {
6001                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6002                }
6003            } else if excerpt.locator <= excerpts[ix - 1].locator {
6004                panic!("excerpts are out-of-order: {:?}", excerpts);
6005            }
6006        }
6007
6008        for (ix, entry) in excerpt_ids.iter().enumerate() {
6009            if ix == 0 {
6010                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6011                    panic!("invalid first excerpt id {:?}", entry.id);
6012                }
6013            } else if entry.id <= excerpt_ids[ix - 1].id {
6014                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6015            }
6016        }
6017
6018        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6019            panic!(
6020                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6021                self.excerpts.summary().text.len,
6022                self.diff_transforms.summary().input,
6023                self.diff_transforms.items(&()),
6024            );
6025        }
6026
6027        let mut prev_transform: Option<&DiffTransform> = None;
6028        for item in self.diff_transforms.iter() {
6029            if let DiffTransform::BufferContent {
6030                summary,
6031                inserted_hunk_info,
6032            } = item
6033            {
6034                if let Some(DiffTransform::BufferContent {
6035                    inserted_hunk_info: prev_inserted_hunk_info,
6036                    ..
6037                }) = prev_transform
6038                {
6039                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6040                        panic!(
6041                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6042                            self.diff_transforms.items(&()));
6043                    }
6044                }
6045                if summary.len == 0 && !self.is_empty() {
6046                    panic!("empty buffer content transform");
6047                }
6048            }
6049            prev_transform = Some(item);
6050        }
6051    }
6052}
6053
6054impl<'a, D> MultiBufferCursor<'a, D>
6055where
6056    D: TextDimension + Ord + Sub<D, Output = D>,
6057{
6058    fn seek(&mut self, position: &D) {
6059        self.cached_region.take();
6060        self.diff_transforms
6061            .seek(&OutputDimension(*position), Bias::Right, &());
6062        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6063            self.diff_transforms.prev(&());
6064        }
6065
6066        let mut excerpt_position = self.diff_transforms.start().1 .0;
6067        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6068            let overshoot = *position - self.diff_transforms.start().0 .0;
6069            excerpt_position.add_assign(&overshoot);
6070        }
6071
6072        self.excerpts
6073            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6074        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6075            self.excerpts.prev(&());
6076        }
6077    }
6078
6079    fn seek_forward(&mut self, position: &D) {
6080        self.cached_region.take();
6081        self.diff_transforms
6082            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6083        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6084            self.diff_transforms.prev(&());
6085        }
6086
6087        let overshoot = *position - self.diff_transforms.start().0 .0;
6088        let mut excerpt_position = self.diff_transforms.start().1 .0;
6089        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6090            excerpt_position.add_assign(&overshoot);
6091        }
6092
6093        self.excerpts
6094            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6095        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6096            self.excerpts.prev(&());
6097        }
6098    }
6099
6100    fn next_excerpt(&mut self) {
6101        self.excerpts.next(&());
6102        self.seek_to_start_of_current_excerpt();
6103    }
6104
6105    fn prev_excerpt(&mut self) {
6106        self.excerpts.prev(&());
6107        self.seek_to_start_of_current_excerpt();
6108    }
6109
6110    fn seek_to_start_of_current_excerpt(&mut self) {
6111        self.cached_region.take();
6112        self.diff_transforms
6113            .seek(self.excerpts.start(), Bias::Left, &());
6114        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6115            && self.diff_transforms.start().1 < *self.excerpts.start()
6116            && self.diff_transforms.next_item().is_some()
6117        {
6118            self.diff_transforms.next(&());
6119        }
6120    }
6121
6122    fn next(&mut self) {
6123        self.cached_region.take();
6124        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6125            cmp::Ordering::Less => self.diff_transforms.next(&()),
6126            cmp::Ordering::Greater => self.excerpts.next(&()),
6127            cmp::Ordering::Equal => {
6128                self.diff_transforms.next(&());
6129                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6130                    || self.diff_transforms.item().is_none()
6131                {
6132                    self.excerpts.next(&());
6133                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6134                    self.diff_transforms.item()
6135                {
6136                    if self
6137                        .excerpts
6138                        .item()
6139                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6140                    {
6141                        self.excerpts.next(&());
6142                    }
6143                }
6144            }
6145        }
6146    }
6147
6148    fn prev(&mut self) {
6149        self.cached_region.take();
6150        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6151            cmp::Ordering::Less => self.excerpts.prev(&()),
6152            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6153            cmp::Ordering::Equal => {
6154                self.diff_transforms.prev(&());
6155                if self.diff_transforms.start().1 < *self.excerpts.start()
6156                    || self.diff_transforms.item().is_none()
6157                {
6158                    self.excerpts.prev(&());
6159                }
6160            }
6161        }
6162    }
6163
6164    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6165        if self.cached_region.is_none() {
6166            self.cached_region = self.build_region();
6167        }
6168        self.cached_region.clone()
6169    }
6170
6171    fn is_at_end_of_excerpt(&mut self) -> bool {
6172        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6173            return false;
6174        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6175            || self.diff_transforms.item().is_none()
6176        {
6177            return true;
6178        }
6179
6180        let next_transform = self.diff_transforms.next_item();
6181        next_transform.map_or(true, |next_transform| match next_transform {
6182            DiffTransform::BufferContent { .. } => true,
6183            DiffTransform::DeletedHunk { hunk_info, .. } => self
6184                .excerpts
6185                .item()
6186                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6187        })
6188    }
6189
6190    fn main_buffer_position(&self) -> Option<D> {
6191        let excerpt = self.excerpts.item()?;
6192        let buffer = &excerpt.buffer;
6193        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6194        let mut buffer_start = buffer_context_start;
6195        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6196        buffer_start.add_assign(&overshoot);
6197        Some(buffer_start)
6198    }
6199
6200    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6201        let excerpt = self.excerpts.item()?;
6202        match self.diff_transforms.item()? {
6203            DiffTransform::DeletedHunk {
6204                buffer_id,
6205                base_text_byte_range,
6206                has_trailing_newline,
6207                hunk_info,
6208                ..
6209            } => {
6210                let diff = self.diffs.get(&buffer_id)?;
6211                let buffer = diff.base_text();
6212                let mut rope_cursor = buffer.as_rope().cursor(0);
6213                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6214                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6215                let mut buffer_end = buffer_start;
6216                buffer_end.add_assign(&buffer_range_len);
6217                let start = self.diff_transforms.start().0 .0;
6218                let end = self.diff_transforms.end(&()).0 .0;
6219                return Some(MultiBufferRegion {
6220                    buffer,
6221                    excerpt,
6222                    has_trailing_newline: *has_trailing_newline,
6223                    is_main_buffer: false,
6224                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6225                        hunk_info.hunk_secondary_status,
6226                    )),
6227                    buffer_range: buffer_start..buffer_end,
6228                    range: start..end,
6229                });
6230            }
6231            DiffTransform::BufferContent {
6232                inserted_hunk_info, ..
6233            } => {
6234                let buffer = &excerpt.buffer;
6235                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6236
6237                let mut start = self.diff_transforms.start().0 .0;
6238                let mut buffer_start = buffer_context_start;
6239                if self.diff_transforms.start().1 < *self.excerpts.start() {
6240                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6241                    start.add_assign(&overshoot);
6242                } else {
6243                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6244                    buffer_start.add_assign(&overshoot);
6245                }
6246
6247                let mut end;
6248                let mut buffer_end;
6249                let has_trailing_newline;
6250                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6251                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6252                    end = self.diff_transforms.end(&()).0 .0;
6253                    buffer_end = buffer_context_start;
6254                    buffer_end.add_assign(&overshoot);
6255                    has_trailing_newline = false;
6256                } else {
6257                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6258                    end = self.diff_transforms.start().0 .0;
6259                    end.add_assign(&overshoot);
6260                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6261                    has_trailing_newline = excerpt.has_trailing_newline;
6262                };
6263
6264                Some(MultiBufferRegion {
6265                    buffer,
6266                    excerpt,
6267                    has_trailing_newline,
6268                    is_main_buffer: true,
6269                    diff_hunk_status: inserted_hunk_info
6270                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6271                    buffer_range: buffer_start..buffer_end,
6272                    range: start..end,
6273                })
6274            }
6275        }
6276    }
6277
6278    fn excerpt(&self) -> Option<&'a Excerpt> {
6279        self.excerpts.item()
6280    }
6281}
6282
6283impl History {
6284    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6285        self.transaction_depth += 1;
6286        if self.transaction_depth == 1 {
6287            let id = self.next_transaction_id.tick();
6288            self.undo_stack.push(Transaction {
6289                id,
6290                buffer_transactions: Default::default(),
6291                first_edit_at: now,
6292                last_edit_at: now,
6293                suppress_grouping: false,
6294            });
6295            Some(id)
6296        } else {
6297            None
6298        }
6299    }
6300
6301    fn end_transaction(
6302        &mut self,
6303        now: Instant,
6304        buffer_transactions: HashMap<BufferId, TransactionId>,
6305    ) -> bool {
6306        assert_ne!(self.transaction_depth, 0);
6307        self.transaction_depth -= 1;
6308        if self.transaction_depth == 0 {
6309            if buffer_transactions.is_empty() {
6310                self.undo_stack.pop();
6311                false
6312            } else {
6313                self.redo_stack.clear();
6314                let transaction = self.undo_stack.last_mut().unwrap();
6315                transaction.last_edit_at = now;
6316                for (buffer_id, transaction_id) in buffer_transactions {
6317                    transaction
6318                        .buffer_transactions
6319                        .entry(buffer_id)
6320                        .or_insert(transaction_id);
6321                }
6322                true
6323            }
6324        } else {
6325            false
6326        }
6327    }
6328
6329    fn push_transaction<'a, T>(
6330        &mut self,
6331        buffer_transactions: T,
6332        now: Instant,
6333        cx: &Context<MultiBuffer>,
6334    ) where
6335        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6336    {
6337        assert_eq!(self.transaction_depth, 0);
6338        let transaction = Transaction {
6339            id: self.next_transaction_id.tick(),
6340            buffer_transactions: buffer_transactions
6341                .into_iter()
6342                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6343                .collect(),
6344            first_edit_at: now,
6345            last_edit_at: now,
6346            suppress_grouping: false,
6347        };
6348        if !transaction.buffer_transactions.is_empty() {
6349            self.undo_stack.push(transaction);
6350            self.redo_stack.clear();
6351        }
6352    }
6353
6354    fn finalize_last_transaction(&mut self) {
6355        if let Some(transaction) = self.undo_stack.last_mut() {
6356            transaction.suppress_grouping = true;
6357        }
6358    }
6359
6360    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6361        if let Some(ix) = self
6362            .undo_stack
6363            .iter()
6364            .rposition(|transaction| transaction.id == transaction_id)
6365        {
6366            Some(self.undo_stack.remove(ix))
6367        } else if let Some(ix) = self
6368            .redo_stack
6369            .iter()
6370            .rposition(|transaction| transaction.id == transaction_id)
6371        {
6372            Some(self.redo_stack.remove(ix))
6373        } else {
6374            None
6375        }
6376    }
6377
6378    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6379        self.undo_stack
6380            .iter()
6381            .find(|transaction| transaction.id == transaction_id)
6382            .or_else(|| {
6383                self.redo_stack
6384                    .iter()
6385                    .find(|transaction| transaction.id == transaction_id)
6386            })
6387    }
6388
6389    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6390        self.undo_stack
6391            .iter_mut()
6392            .find(|transaction| transaction.id == transaction_id)
6393            .or_else(|| {
6394                self.redo_stack
6395                    .iter_mut()
6396                    .find(|transaction| transaction.id == transaction_id)
6397            })
6398    }
6399
6400    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6401        assert_eq!(self.transaction_depth, 0);
6402        if let Some(transaction) = self.undo_stack.pop() {
6403            self.redo_stack.push(transaction);
6404            self.redo_stack.last_mut()
6405        } else {
6406            None
6407        }
6408    }
6409
6410    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6411        assert_eq!(self.transaction_depth, 0);
6412        if let Some(transaction) = self.redo_stack.pop() {
6413            self.undo_stack.push(transaction);
6414            self.undo_stack.last_mut()
6415        } else {
6416            None
6417        }
6418    }
6419
6420    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6421        let ix = self
6422            .undo_stack
6423            .iter()
6424            .rposition(|transaction| transaction.id == transaction_id)?;
6425        let transaction = self.undo_stack.remove(ix);
6426        self.redo_stack.push(transaction);
6427        self.redo_stack.last()
6428    }
6429
6430    fn group(&mut self) -> Option<TransactionId> {
6431        let mut count = 0;
6432        let mut transactions = self.undo_stack.iter();
6433        if let Some(mut transaction) = transactions.next_back() {
6434            while let Some(prev_transaction) = transactions.next_back() {
6435                if !prev_transaction.suppress_grouping
6436                    && transaction.first_edit_at - prev_transaction.last_edit_at
6437                        <= self.group_interval
6438                {
6439                    transaction = prev_transaction;
6440                    count += 1;
6441                } else {
6442                    break;
6443                }
6444            }
6445        }
6446        self.group_trailing(count)
6447    }
6448
6449    fn group_until(&mut self, transaction_id: TransactionId) {
6450        let mut count = 0;
6451        for transaction in self.undo_stack.iter().rev() {
6452            if transaction.id == transaction_id {
6453                self.group_trailing(count);
6454                break;
6455            } else if transaction.suppress_grouping {
6456                break;
6457            } else {
6458                count += 1;
6459            }
6460        }
6461    }
6462
6463    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6464        let new_len = self.undo_stack.len() - n;
6465        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6466        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6467            if let Some(transaction) = transactions_to_merge.last() {
6468                last_transaction.last_edit_at = transaction.last_edit_at;
6469            }
6470            for to_merge in transactions_to_merge {
6471                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6472                    last_transaction
6473                        .buffer_transactions
6474                        .entry(*buffer_id)
6475                        .or_insert(*transaction_id);
6476                }
6477            }
6478        }
6479
6480        self.undo_stack.truncate(new_len);
6481        self.undo_stack.last().map(|t| t.id)
6482    }
6483}
6484
6485impl Excerpt {
6486    fn new(
6487        id: ExcerptId,
6488        locator: Locator,
6489        buffer_id: BufferId,
6490        buffer: BufferSnapshot,
6491        range: ExcerptRange<text::Anchor>,
6492        has_trailing_newline: bool,
6493    ) -> Self {
6494        Excerpt {
6495            id,
6496            locator,
6497            max_buffer_row: range.context.end.to_point(&buffer).row,
6498            text_summary: buffer
6499                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6500            buffer_id,
6501            buffer,
6502            range,
6503            has_trailing_newline,
6504        }
6505    }
6506
6507    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6508        let content_start = self.range.context.start.to_offset(&self.buffer);
6509        let chunks_start = content_start + range.start;
6510        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6511
6512        let footer_height = if self.has_trailing_newline
6513            && range.start <= self.text_summary.len
6514            && range.end > self.text_summary.len
6515        {
6516            1
6517        } else {
6518            0
6519        };
6520
6521        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6522
6523        ExcerptChunks {
6524            excerpt_id: self.id,
6525            content_chunks,
6526            footer_height,
6527        }
6528    }
6529
6530    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6531        let content_start = self.range.context.start.to_offset(&self.buffer);
6532        let chunks_start = content_start + range.start;
6533        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6534        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6535        excerpt_chunks.footer_height = if self.has_trailing_newline
6536            && range.start <= self.text_summary.len
6537            && range.end > self.text_summary.len
6538        {
6539            1
6540        } else {
6541            0
6542        };
6543    }
6544
6545    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6546        if text_anchor
6547            .cmp(&self.range.context.start, &self.buffer)
6548            .is_lt()
6549        {
6550            self.range.context.start
6551        } else if text_anchor
6552            .cmp(&self.range.context.end, &self.buffer)
6553            .is_gt()
6554        {
6555            self.range.context.end
6556        } else {
6557            text_anchor
6558        }
6559    }
6560
6561    fn contains(&self, anchor: &Anchor) -> bool {
6562        Some(self.buffer_id) == anchor.buffer_id
6563            && self
6564                .range
6565                .context
6566                .start
6567                .cmp(&anchor.text_anchor, &self.buffer)
6568                .is_le()
6569            && self
6570                .range
6571                .context
6572                .end
6573                .cmp(&anchor.text_anchor, &self.buffer)
6574                .is_ge()
6575    }
6576
6577    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6578    fn buffer_start_offset(&self) -> usize {
6579        self.range.context.start.to_offset(&self.buffer)
6580    }
6581
6582    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6583    fn buffer_end_offset(&self) -> usize {
6584        self.buffer_start_offset() + self.text_summary.len
6585    }
6586}
6587
6588impl<'a> MultiBufferExcerpt<'a> {
6589    pub fn id(&self) -> ExcerptId {
6590        self.excerpt.id
6591    }
6592
6593    pub fn buffer_id(&self) -> BufferId {
6594        self.excerpt.buffer_id
6595    }
6596
6597    pub fn start_anchor(&self) -> Anchor {
6598        Anchor {
6599            buffer_id: Some(self.excerpt.buffer_id),
6600            excerpt_id: self.excerpt.id,
6601            text_anchor: self.excerpt.range.context.start,
6602            diff_base_anchor: None,
6603        }
6604    }
6605
6606    pub fn end_anchor(&self) -> Anchor {
6607        Anchor {
6608            buffer_id: Some(self.excerpt.buffer_id),
6609            excerpt_id: self.excerpt.id,
6610            text_anchor: self.excerpt.range.context.end,
6611            diff_base_anchor: None,
6612        }
6613    }
6614
6615    pub fn buffer(&self) -> &'a BufferSnapshot {
6616        &self.excerpt.buffer
6617    }
6618
6619    pub fn buffer_range(&self) -> Range<usize> {
6620        self.buffer_offset
6621            ..self
6622                .excerpt
6623                .range
6624                .context
6625                .end
6626                .to_offset(&self.excerpt.buffer.text)
6627    }
6628
6629    pub fn start_offset(&self) -> usize {
6630        self.offset
6631    }
6632
6633    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6634    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6635        self.map_range_to_buffer(offset..offset).start
6636    }
6637
6638    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6639    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6640        self.diff_transforms
6641            .seek(&OutputDimension(range.start), Bias::Right, &());
6642        let start = self.map_offset_to_buffer_internal(range.start);
6643        let end = if range.end > range.start {
6644            self.diff_transforms
6645                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6646            self.map_offset_to_buffer_internal(range.end)
6647        } else {
6648            start
6649        };
6650        start..end
6651    }
6652
6653    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6654        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6655        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6656            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6657        };
6658        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6659        self.buffer_offset + offset_in_excerpt
6660    }
6661
6662    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6663    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6664        self.map_range_from_buffer(buffer_offset..buffer_offset)
6665            .start
6666    }
6667
6668    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6669    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6670        if buffer_range.start < self.buffer_offset {
6671            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6672            return buffer_range;
6673        }
6674        let overshoot = buffer_range.start - self.buffer_offset;
6675        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6676        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6677        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6678            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6679            return buffer_range;
6680        }
6681        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6682        let start = self.diff_transforms.start().0 .0 + overshoot;
6683
6684        let end = if buffer_range.end > buffer_range.start {
6685            let overshoot = buffer_range.end - self.buffer_offset;
6686            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6687            self.diff_transforms
6688                .seek_forward(&excerpt_offset, Bias::Right, &());
6689            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6690            self.diff_transforms.start().0 .0 + overshoot
6691        } else {
6692            start
6693        };
6694
6695        start..end
6696    }
6697
6698    /// Returns true if the entirety of the given range is in the buffer's excerpt
6699    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6700        range.start >= self.excerpt.buffer_start_offset()
6701            && range.end <= self.excerpt.buffer_end_offset()
6702    }
6703
6704    pub fn max_buffer_row(&self) -> u32 {
6705        self.excerpt.max_buffer_row
6706    }
6707}
6708
6709impl ExcerptId {
6710    pub fn min() -> Self {
6711        Self(0)
6712    }
6713
6714    pub fn max() -> Self {
6715        Self(usize::MAX)
6716    }
6717
6718    pub fn to_proto(&self) -> u64 {
6719        self.0 as _
6720    }
6721
6722    pub fn from_proto(proto: u64) -> Self {
6723        Self(proto as _)
6724    }
6725
6726    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6727        let a = snapshot.excerpt_locator_for_id(*self);
6728        let b = snapshot.excerpt_locator_for_id(*other);
6729        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6730    }
6731}
6732
6733impl From<ExcerptId> for usize {
6734    fn from(val: ExcerptId) -> Self {
6735        val.0
6736    }
6737}
6738
6739impl fmt::Debug for Excerpt {
6740    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6741        f.debug_struct("Excerpt")
6742            .field("id", &self.id)
6743            .field("locator", &self.locator)
6744            .field("buffer_id", &self.buffer_id)
6745            .field("range", &self.range)
6746            .field("text_summary", &self.text_summary)
6747            .field("has_trailing_newline", &self.has_trailing_newline)
6748            .finish()
6749    }
6750}
6751
6752impl sum_tree::Item for Excerpt {
6753    type Summary = ExcerptSummary;
6754
6755    fn summary(&self, _cx: &()) -> Self::Summary {
6756        let mut text = self.text_summary;
6757        if self.has_trailing_newline {
6758            text += TextSummary::from("\n");
6759        }
6760        ExcerptSummary {
6761            excerpt_id: self.id,
6762            excerpt_locator: self.locator.clone(),
6763            widest_line_number: self.max_buffer_row,
6764            text,
6765        }
6766    }
6767}
6768
6769impl sum_tree::Item for ExcerptIdMapping {
6770    type Summary = ExcerptId;
6771
6772    fn summary(&self, _cx: &()) -> Self::Summary {
6773        self.id
6774    }
6775}
6776
6777impl sum_tree::KeyedItem for ExcerptIdMapping {
6778    type Key = ExcerptId;
6779
6780    fn key(&self) -> Self::Key {
6781        self.id
6782    }
6783}
6784
6785impl DiffTransform {
6786    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6787        match self {
6788            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6789            DiffTransform::BufferContent {
6790                inserted_hunk_info, ..
6791            } => *inserted_hunk_info,
6792        }
6793    }
6794}
6795
6796impl sum_tree::Item for DiffTransform {
6797    type Summary = DiffTransformSummary;
6798
6799    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6800        match self {
6801            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6802                input: *summary,
6803                output: *summary,
6804            },
6805            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6806                input: TextSummary::default(),
6807                output: *summary,
6808            },
6809        }
6810    }
6811}
6812
6813impl DiffTransformSummary {
6814    fn excerpt_len(&self) -> ExcerptOffset {
6815        ExcerptOffset::new(self.input.len)
6816    }
6817}
6818
6819impl sum_tree::Summary for DiffTransformSummary {
6820    type Context = ();
6821
6822    fn zero(_: &Self::Context) -> Self {
6823        DiffTransformSummary {
6824            input: TextSummary::default(),
6825            output: TextSummary::default(),
6826        }
6827    }
6828
6829    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6830        self.input += &summary.input;
6831        self.output += &summary.output;
6832    }
6833}
6834
6835impl sum_tree::Summary for ExcerptId {
6836    type Context = ();
6837
6838    fn zero(_cx: &()) -> Self {
6839        Default::default()
6840    }
6841
6842    fn add_summary(&mut self, other: &Self, _: &()) {
6843        *self = *other;
6844    }
6845}
6846
6847impl sum_tree::Summary for ExcerptSummary {
6848    type Context = ();
6849
6850    fn zero(_cx: &()) -> Self {
6851        Default::default()
6852    }
6853
6854    fn add_summary(&mut self, summary: &Self, _: &()) {
6855        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6856        self.excerpt_locator = summary.excerpt_locator.clone();
6857        self.text.add_summary(&summary.text, &());
6858        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6859    }
6860}
6861
6862impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6863    fn zero(_cx: &()) -> Self {
6864        Default::default()
6865    }
6866
6867    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6868        self.value += summary.text.len;
6869    }
6870}
6871
6872impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6873    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6874        Ord::cmp(&self.value, &cursor_location.text.len)
6875    }
6876}
6877
6878impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6879    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6880        Ord::cmp(&Some(self), cursor_location)
6881    }
6882}
6883
6884impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6885    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6886        Ord::cmp(self, &cursor_location.excerpt_locator)
6887    }
6888}
6889
6890impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6891    fn zero(_cx: &()) -> Self {
6892        Default::default()
6893    }
6894
6895    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6896        self.value += summary.text.lines;
6897    }
6898}
6899
6900impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6901    for ExcerptDimension<D>
6902{
6903    fn zero(_: &()) -> Self {
6904        ExcerptDimension(D::default())
6905    }
6906
6907    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6908        self.0.add_assign(&D::from_text_summary(&summary.text))
6909    }
6910}
6911
6912impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6913    fn zero(_cx: &()) -> Self {
6914        Default::default()
6915    }
6916
6917    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6918        *self = Some(&summary.excerpt_locator);
6919    }
6920}
6921
6922impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6923    fn zero(_cx: &()) -> Self {
6924        Default::default()
6925    }
6926
6927    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6928        *self = Some(summary.excerpt_id);
6929    }
6930}
6931
6932#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6933struct ExcerptDimension<T>(T);
6934
6935#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6936struct OutputDimension<T>(T);
6937
6938impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6939    fn zero(_: &()) -> Self {
6940        ExcerptOffset::new(0)
6941    }
6942
6943    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6944        self.value += summary.input.len;
6945    }
6946}
6947
6948impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6949    fn zero(_: &()) -> Self {
6950        ExcerptPoint::new(0, 0)
6951    }
6952
6953    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6954        self.value += summary.input.lines;
6955    }
6956}
6957
6958impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6959    for ExcerptDimension<D>
6960{
6961    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6962        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6963    }
6964}
6965
6966impl<D: TextDimension + Ord>
6967    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6968    for ExcerptDimension<D>
6969{
6970    fn cmp(
6971        &self,
6972        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6973        _: &(),
6974    ) -> cmp::Ordering {
6975        Ord::cmp(&self.0, &cursor_location.1 .0)
6976    }
6977}
6978
6979impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6980    fn zero(_: &()) -> Self {
6981        ExcerptDimension(D::default())
6982    }
6983
6984    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6985        self.0.add_assign(&D::from_text_summary(&summary.input))
6986    }
6987}
6988
6989impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6990    fn zero(_: &()) -> Self {
6991        OutputDimension(D::default())
6992    }
6993
6994    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6995        self.0.add_assign(&D::from_text_summary(&summary.output))
6996    }
6997}
6998
6999impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7000    fn zero(_: &()) -> Self {
7001        TextSummary::default()
7002    }
7003
7004    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7005        *self += summary.output
7006    }
7007}
7008
7009impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7010    fn zero(_: &()) -> Self {
7011        0
7012    }
7013
7014    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7015        *self += summary.output.len
7016    }
7017}
7018
7019impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7020    fn zero(_: &()) -> Self {
7021        Point::new(0, 0)
7022    }
7023
7024    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7025        *self += summary.output.lines
7026    }
7027}
7028
7029impl MultiBufferRows<'_> {
7030    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7031        self.point = Point::new(row, 0);
7032        self.cursor.seek(&self.point);
7033    }
7034}
7035
7036impl Iterator for MultiBufferRows<'_> {
7037    type Item = RowInfo;
7038
7039    fn next(&mut self) -> Option<Self::Item> {
7040        if self.is_empty && self.point.row == 0 {
7041            self.point += Point::new(1, 0);
7042            return Some(RowInfo {
7043                buffer_id: None,
7044                buffer_row: Some(0),
7045                multibuffer_row: Some(MultiBufferRow(0)),
7046                diff_status: None,
7047            });
7048        }
7049
7050        let mut region = self.cursor.region()?;
7051        while self.point >= region.range.end {
7052            self.cursor.next();
7053            if let Some(next_region) = self.cursor.region() {
7054                region = next_region;
7055            } else {
7056                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7057                    let multibuffer_row = MultiBufferRow(self.point.row);
7058                    self.point += Point::new(1, 0);
7059                    let last_excerpt = self
7060                        .cursor
7061                        .excerpts
7062                        .item()
7063                        .or(self.cursor.excerpts.prev_item())?;
7064                    let last_row = last_excerpt
7065                        .range
7066                        .context
7067                        .end
7068                        .to_point(&last_excerpt.buffer)
7069                        .row;
7070                    return Some(RowInfo {
7071                        buffer_id: Some(last_excerpt.buffer_id),
7072                        buffer_row: Some(last_row),
7073                        multibuffer_row: Some(multibuffer_row),
7074                        diff_status: None,
7075                    });
7076                } else {
7077                    return None;
7078                }
7079            };
7080        }
7081
7082        let overshoot = self.point - region.range.start;
7083        let buffer_point = region.buffer_range.start + overshoot;
7084        let result = Some(RowInfo {
7085            buffer_id: Some(region.buffer.remote_id()),
7086            buffer_row: Some(buffer_point.row),
7087            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7088            diff_status: region
7089                .diff_hunk_status
7090                .filter(|_| self.point < region.range.end),
7091        });
7092        self.point += Point::new(1, 0);
7093        result
7094    }
7095}
7096
7097impl<'a> MultiBufferChunks<'a> {
7098    pub fn offset(&self) -> usize {
7099        self.range.start
7100    }
7101
7102    pub fn seek(&mut self, range: Range<usize>) {
7103        self.diff_transforms.seek(&range.end, Bias::Right, &());
7104        let mut excerpt_end = self.diff_transforms.start().1;
7105        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7106            let overshoot = range.end - self.diff_transforms.start().0;
7107            excerpt_end.value += overshoot;
7108        }
7109
7110        self.diff_transforms.seek(&range.start, Bias::Right, &());
7111        let mut excerpt_start = self.diff_transforms.start().1;
7112        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7113            let overshoot = range.start - self.diff_transforms.start().0;
7114            excerpt_start.value += overshoot;
7115        }
7116
7117        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7118        self.buffer_chunk.take();
7119        self.range = range;
7120    }
7121
7122    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7123        self.excerpt_offset_range = new_range.clone();
7124        self.excerpts.seek(&new_range.start, Bias::Right, &());
7125        if let Some(excerpt) = self.excerpts.item() {
7126            let excerpt_start = *self.excerpts.start();
7127            if let Some(excerpt_chunks) = self
7128                .excerpt_chunks
7129                .as_mut()
7130                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7131            {
7132                excerpt.seek_chunks(
7133                    excerpt_chunks,
7134                    (self.excerpt_offset_range.start - excerpt_start).value
7135                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7136                );
7137            } else {
7138                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7139                    (self.excerpt_offset_range.start - excerpt_start).value
7140                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7141                    self.language_aware,
7142                ));
7143            }
7144        } else {
7145            self.excerpt_chunks = None;
7146        }
7147    }
7148
7149    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7150        loop {
7151            if self.excerpt_offset_range.is_empty() {
7152                return None;
7153            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7154                self.excerpt_offset_range.start.value += chunk.text.len();
7155                return Some(chunk);
7156            } else {
7157                self.excerpts.next(&());
7158                let excerpt = self.excerpts.item()?;
7159                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7160                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7161                    self.language_aware,
7162                ));
7163            }
7164        }
7165    }
7166}
7167
7168impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7169    type Item = &'a str;
7170
7171    fn next(&mut self) -> Option<Self::Item> {
7172        let mut region = self.cursor.region()?;
7173        if self.offset == region.range.start {
7174            self.cursor.prev();
7175            region = self.cursor.region()?;
7176            let start_overshoot = self.start.saturating_sub(region.range.start);
7177            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7178                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7179            ));
7180        }
7181
7182        if self.offset == region.range.end && region.has_trailing_newline {
7183            self.offset -= 1;
7184            Some("\n")
7185        } else {
7186            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7187            self.offset -= chunk.len();
7188            Some(chunk)
7189        }
7190    }
7191}
7192
7193impl<'a> Iterator for MultiBufferChunks<'a> {
7194    type Item = Chunk<'a>;
7195
7196    fn next(&mut self) -> Option<Chunk<'a>> {
7197        if self.range.start >= self.range.end {
7198            return None;
7199        }
7200        if self.range.start == self.diff_transforms.end(&()).0 {
7201            self.diff_transforms.next(&());
7202        }
7203
7204        let diff_transform_start = self.diff_transforms.start().0;
7205        let diff_transform_end = self.diff_transforms.end(&()).0;
7206        debug_assert!(self.range.start < diff_transform_end);
7207
7208        let diff_transform = self.diff_transforms.item()?;
7209        match diff_transform {
7210            DiffTransform::BufferContent { .. } => {
7211                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7212                    chunk
7213                } else {
7214                    let chunk = self.next_excerpt_chunk().unwrap();
7215                    self.buffer_chunk.insert(chunk)
7216                };
7217
7218                let chunk_end = self.range.start + chunk.text.len();
7219                let diff_transform_end = diff_transform_end.min(self.range.end);
7220
7221                if diff_transform_end < chunk_end {
7222                    let (before, after) =
7223                        chunk.text.split_at(diff_transform_end - self.range.start);
7224                    self.range.start = diff_transform_end;
7225                    chunk.text = after;
7226                    Some(Chunk {
7227                        text: before,
7228                        ..chunk.clone()
7229                    })
7230                } else {
7231                    self.range.start = chunk_end;
7232                    self.buffer_chunk.take()
7233                }
7234            }
7235            DiffTransform::DeletedHunk {
7236                buffer_id,
7237                base_text_byte_range,
7238                has_trailing_newline,
7239                ..
7240            } => {
7241                let base_text_start =
7242                    base_text_byte_range.start + self.range.start - diff_transform_start;
7243                let base_text_end =
7244                    base_text_byte_range.start + self.range.end - diff_transform_start;
7245                let base_text_end = base_text_end.min(base_text_byte_range.end);
7246
7247                let mut chunks = if let Some((_, mut chunks)) = self
7248                    .diff_base_chunks
7249                    .take()
7250                    .filter(|(id, _)| id == buffer_id)
7251                {
7252                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7253                    {
7254                        chunks.seek(base_text_start..base_text_end);
7255                    }
7256                    chunks
7257                } else {
7258                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7259                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7260                };
7261
7262                let chunk = if let Some(chunk) = chunks.next() {
7263                    self.range.start += chunk.text.len();
7264                    self.diff_base_chunks = Some((*buffer_id, chunks));
7265                    chunk
7266                } else {
7267                    debug_assert!(has_trailing_newline);
7268                    self.range.start += "\n".len();
7269                    Chunk {
7270                        text: "\n",
7271                        ..Default::default()
7272                    }
7273                };
7274                Some(chunk)
7275            }
7276        }
7277    }
7278}
7279
7280impl MultiBufferBytes<'_> {
7281    fn consume(&mut self, len: usize) {
7282        self.range.start += len;
7283        self.chunk = &self.chunk[len..];
7284
7285        if !self.range.is_empty() && self.chunk.is_empty() {
7286            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7287                self.chunk = chunk;
7288            } else if self.has_trailing_newline {
7289                self.has_trailing_newline = false;
7290                self.chunk = b"\n";
7291            } else {
7292                self.cursor.next();
7293                if let Some(region) = self.cursor.region() {
7294                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7295                        region.buffer_range.start
7296                            ..(region.buffer_range.start + self.range.end - region.range.start)
7297                                .min(region.buffer_range.end),
7298                    );
7299                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7300                    self.excerpt_bytes = Some(excerpt_bytes);
7301                    self.has_trailing_newline =
7302                        region.has_trailing_newline && self.range.end >= region.range.end;
7303                    if self.chunk.is_empty() && self.has_trailing_newline {
7304                        self.has_trailing_newline = false;
7305                        self.chunk = b"\n";
7306                    }
7307                }
7308            }
7309        }
7310    }
7311}
7312
7313impl<'a> Iterator for MultiBufferBytes<'a> {
7314    type Item = &'a [u8];
7315
7316    fn next(&mut self) -> Option<Self::Item> {
7317        let chunk = self.chunk;
7318        if chunk.is_empty() {
7319            None
7320        } else {
7321            self.consume(chunk.len());
7322            Some(chunk)
7323        }
7324    }
7325}
7326
7327impl io::Read for MultiBufferBytes<'_> {
7328    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7329        let len = cmp::min(buf.len(), self.chunk.len());
7330        buf[..len].copy_from_slice(&self.chunk[..len]);
7331        if len > 0 {
7332            self.consume(len);
7333        }
7334        Ok(len)
7335    }
7336}
7337
7338impl io::Read for ReversedMultiBufferBytes<'_> {
7339    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7340        let len = cmp::min(buf.len(), self.chunk.len());
7341        buf[..len].copy_from_slice(&self.chunk[..len]);
7342        buf[..len].reverse();
7343        if len > 0 {
7344            self.range.end -= len;
7345            self.chunk = &self.chunk[..self.chunk.len() - len];
7346            if !self.range.is_empty() && self.chunk.is_empty() {
7347                if let Some(chunk) = self.chunks.next() {
7348                    self.chunk = chunk.as_bytes();
7349                }
7350            }
7351        }
7352        Ok(len)
7353    }
7354}
7355
7356impl<'a> Iterator for ExcerptChunks<'a> {
7357    type Item = Chunk<'a>;
7358
7359    fn next(&mut self) -> Option<Self::Item> {
7360        if let Some(chunk) = self.content_chunks.next() {
7361            return Some(chunk);
7362        }
7363
7364        if self.footer_height > 0 {
7365            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7366            self.footer_height = 0;
7367            return Some(Chunk {
7368                text,
7369                ..Default::default()
7370            });
7371        }
7372
7373        None
7374    }
7375}
7376
7377impl ToOffset for Point {
7378    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7379        snapshot.point_to_offset(*self)
7380    }
7381}
7382
7383impl ToOffset for usize {
7384    #[track_caller]
7385    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7386        assert!(*self <= snapshot.len(), "offset is out of range");
7387        *self
7388    }
7389}
7390
7391impl ToOffset for OffsetUtf16 {
7392    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7393        snapshot.offset_utf16_to_offset(*self)
7394    }
7395}
7396
7397impl ToOffset for PointUtf16 {
7398    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7399        snapshot.point_utf16_to_offset(*self)
7400    }
7401}
7402
7403impl ToOffsetUtf16 for OffsetUtf16 {
7404    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7405        *self
7406    }
7407}
7408
7409impl ToOffsetUtf16 for usize {
7410    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7411        snapshot.offset_to_offset_utf16(*self)
7412    }
7413}
7414
7415impl ToPoint for usize {
7416    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7417        snapshot.offset_to_point(*self)
7418    }
7419}
7420
7421impl ToPoint for Point {
7422    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7423        *self
7424    }
7425}
7426
7427impl ToPointUtf16 for usize {
7428    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7429        snapshot.offset_to_point_utf16(*self)
7430    }
7431}
7432
7433impl ToPointUtf16 for Point {
7434    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7435        snapshot.point_to_point_utf16(*self)
7436    }
7437}
7438
7439impl ToPointUtf16 for PointUtf16 {
7440    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7441        *self
7442    }
7443}
7444
7445impl From<ExcerptId> for EntityId {
7446    fn from(id: ExcerptId) -> Self {
7447        EntityId::from(id.0 as u64)
7448    }
7449}
7450
7451pub fn build_excerpt_ranges<T>(
7452    buffer: &BufferSnapshot,
7453    ranges: &[Range<T>],
7454    context_line_count: u32,
7455) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7456where
7457    T: text::ToPoint,
7458{
7459    let max_point = buffer.max_point();
7460    let mut range_counts = Vec::new();
7461    let mut excerpt_ranges = Vec::new();
7462    let mut range_iter = ranges
7463        .iter()
7464        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7465        .peekable();
7466    while let Some(range) = range_iter.next() {
7467        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7468        let row = (range.end.row + context_line_count).min(max_point.row);
7469        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7470
7471        let mut ranges_in_excerpt = 1;
7472
7473        while let Some(next_range) = range_iter.peek() {
7474            if next_range.start.row <= excerpt_end.row + context_line_count {
7475                let row = (next_range.end.row + context_line_count).min(max_point.row);
7476                excerpt_end = Point::new(row, buffer.line_len(row));
7477
7478                ranges_in_excerpt += 1;
7479                range_iter.next();
7480            } else {
7481                break;
7482            }
7483        }
7484
7485        excerpt_ranges.push(ExcerptRange {
7486            context: excerpt_start..excerpt_end,
7487            primary: Some(range),
7488        });
7489        range_counts.push(ranges_in_excerpt);
7490    }
7491
7492    (excerpt_ranges, range_counts)
7493}