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::{Result, anyhow};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  17use itertools::Itertools;
  18use language::{
  19    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  20    CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState, File,
  21    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  22    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  23    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  24    language_settings::{LanguageSettings, language_settings},
  25};
  26
  27use rope::DimensionPair;
  28use smallvec::SmallVec;
  29use smol::future::yield_now;
  30use std::{
  31    any::type_name,
  32    borrow::Cow,
  33    cell::{Cell, Ref, RefCell},
  34    cmp, fmt,
  35    future::Future,
  36    io,
  37    iter::{self, FromIterator},
  38    mem,
  39    ops::{Range, RangeBounds, Sub},
  40    rc::Rc,
  41    str,
  42    sync::Arc,
  43    time::{Duration, Instant},
  44};
  45use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, Summary, TreeMap};
  46use text::{
  47    BufferId, Edit, LineIndent, TextSummary,
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50};
  51use theme::SyntaxTheme;
  52use util::{post_inc, rel_path::RelPath};
  53
  54const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  55
  56#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  57pub struct ExcerptId(u32);
  58
  59/// One or more [`Buffers`](Buffer) being edited in a single view.
  60///
  61/// See <https://zed.dev/features#multi-buffers>
  62pub struct MultiBuffer {
  63    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  64    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  65    snapshot: RefCell<MultiBufferSnapshot>,
  66    /// Contains the state of the buffers being edited
  67    buffers: HashMap<BufferId, BufferState>,
  68    /// Mapping from path keys to their excerpts.
  69    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  70    /// Mapping from excerpt IDs to their path key.
  71    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  72    /// Mapping from buffer IDs to their diff states
  73    diffs: HashMap<BufferId, DiffState>,
  74    subscriptions: Topic,
  75    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  76    singleton: bool,
  77    /// The history of the multi-buffer.
  78    history: History,
  79    /// The explicit title of the multi-buffer.
  80    /// If `None`, it will be derived from the underlying path or content.
  81    title: Option<String>,
  82    /// The writing capability of the multi-buffer.
  83    capability: Capability,
  84    buffer_changed_since_sync: Rc<Cell<bool>>,
  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        removed_buffer_ids: Vec<BufferId>,
  97    },
  98    ExcerptsExpanded {
  99        ids: Vec<ExcerptId>,
 100    },
 101    ExcerptsEdited {
 102        excerpt_ids: Vec<ExcerptId>,
 103        buffer_ids: Vec<BufferId>,
 104    },
 105    DiffHunksToggled,
 106    Edited {
 107        edited_buffer: Option<Entity<Buffer>>,
 108    },
 109    TransactionUndone {
 110        transaction_id: TransactionId,
 111    },
 112    Reloaded,
 113    LanguageChanged(BufferId),
 114    Reparsed(BufferId),
 115    Saved,
 116    FileHandleChanged,
 117    DirtyChanged,
 118    DiagnosticsUpdated,
 119    BufferDiffChanged,
 120}
 121
 122/// A diff hunk, representing a range of consequent lines in a multibuffer.
 123#[derive(Debug, Clone, PartialEq, Eq)]
 124pub struct MultiBufferDiffHunk {
 125    /// The row range in the multibuffer where this diff hunk appears.
 126    pub row_range: Range<MultiBufferRow>,
 127    /// The buffer ID that this hunk belongs to.
 128    pub buffer_id: BufferId,
 129    /// The range of the underlying buffer that this hunk corresponds to.
 130    pub buffer_range: Range<text::Anchor>,
 131    /// The excerpt that contains the diff hunk.
 132    pub excerpt_id: ExcerptId,
 133    /// The range within the buffer's diff base that this hunk corresponds to.
 134    pub diff_base_byte_range: Range<usize>,
 135    /// Whether or not this hunk also appears in the 'secondary diff'.
 136    pub secondary_status: DiffHunkSecondaryStatus,
 137}
 138
 139impl MultiBufferDiffHunk {
 140    pub fn status(&self) -> DiffHunkStatus {
 141        let kind = if self.buffer_range.start == self.buffer_range.end {
 142            DiffHunkStatusKind::Deleted
 143        } else if self.diff_base_byte_range.is_empty() {
 144            DiffHunkStatusKind::Added
 145        } else {
 146            DiffHunkStatusKind::Modified
 147        };
 148        DiffHunkStatus {
 149            kind,
 150            secondary: self.secondary_status,
 151        }
 152    }
 153
 154    pub fn is_created_file(&self) -> bool {
 155        self.diff_base_byte_range == (0..0)
 156            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 157    }
 158
 159    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 160        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 161        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 162        start..end
 163    }
 164}
 165
 166#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 167pub struct PathKey {
 168    // Used by the derived PartialOrd & Ord
 169    sort_prefix: Option<u64>,
 170    path: Arc<RelPath>,
 171}
 172
 173impl PathKey {
 174    pub fn with_sort_prefix(sort_prefix: u64, path: Arc<RelPath>) -> Self {
 175        Self {
 176            sort_prefix: Some(sort_prefix),
 177            path,
 178        }
 179    }
 180
 181    pub fn for_buffer(buffer: &Entity<Buffer>, cx: &App) -> Self {
 182        if let Some(file) = buffer.read(cx).file() {
 183            Self::with_sort_prefix(file.worktree_id(cx).to_proto(), file.path().clone())
 184        } else {
 185            Self {
 186                sort_prefix: None,
 187                path: RelPath::unix(&buffer.entity_id().to_string())
 188                    .unwrap()
 189                    .into_arc(),
 190            }
 191        }
 192    }
 193
 194    #[cfg(any(test, feature = "test-support"))]
 195    pub fn path(&self) -> &Arc<RelPath> {
 196        &self.path
 197    }
 198}
 199
 200pub type MultiBufferPoint = Point;
 201type ExcerptOffset = TypedOffset<Excerpt>;
 202type ExcerptPoint = TypedPoint<Excerpt>;
 203
 204#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 205#[serde(transparent)]
 206pub struct MultiBufferRow(pub u32);
 207
 208impl MultiBufferRow {
 209    pub const MIN: Self = Self(0);
 210    pub const MAX: Self = Self(u32::MAX);
 211}
 212
 213impl std::ops::Add<usize> for MultiBufferRow {
 214    type Output = Self;
 215
 216    fn add(self, rhs: usize) -> Self::Output {
 217        MultiBufferRow(self.0 + rhs as u32)
 218    }
 219}
 220
 221#[derive(Clone)]
 222struct History {
 223    next_transaction_id: TransactionId,
 224    undo_stack: Vec<Transaction>,
 225    redo_stack: Vec<Transaction>,
 226    transaction_depth: usize,
 227    group_interval: Duration,
 228}
 229
 230#[derive(Clone)]
 231struct Transaction {
 232    id: TransactionId,
 233    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 234    first_edit_at: Instant,
 235    last_edit_at: Instant,
 236    suppress_grouping: bool,
 237}
 238
 239pub trait ToOffset: 'static + fmt::Debug {
 240    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 241}
 242
 243pub trait ToOffsetUtf16: 'static + fmt::Debug {
 244    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 245}
 246
 247pub trait ToPoint: 'static + fmt::Debug {
 248    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 249}
 250
 251pub trait ToPointUtf16: 'static + fmt::Debug {
 252    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 253}
 254
 255struct BufferState {
 256    buffer: Entity<Buffer>,
 257    last_version: RefCell<clock::Global>,
 258    last_non_text_state_update_count: Cell<usize>,
 259    excerpts: Vec<Locator>,
 260    _subscriptions: [gpui::Subscription; 2],
 261}
 262
 263struct DiffState {
 264    diff: Entity<BufferDiff>,
 265    _subscription: gpui::Subscription,
 266}
 267
 268impl DiffState {
 269    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 270        DiffState {
 271            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 272                BufferDiffEvent::DiffChanged { changed_range } => {
 273                    if let Some(changed_range) = changed_range.clone() {
 274                        this.buffer_diff_changed(diff, changed_range, cx)
 275                    }
 276                    cx.emit(Event::BufferDiffChanged);
 277                }
 278                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 279                _ => {}
 280            }),
 281            diff,
 282        }
 283    }
 284}
 285
 286/// The contents of a [`MultiBuffer`] at a single point in time.
 287#[derive(Clone, Default)]
 288pub struct MultiBufferSnapshot {
 289    singleton: bool,
 290    /* mut */
 291    excerpts: SumTree<Excerpt>,
 292    /* mut */
 293    excerpt_ids: SumTree<ExcerptIdMapping>,
 294    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 295    diff_transforms: SumTree<DiffTransform>,
 296    /* mut */
 297    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 298    /* mut */
 299    trailing_excerpt_update_count: usize,
 300    all_diff_hunks_expanded: bool,
 301    non_text_state_update_count: usize,
 302    edit_count: usize,
 303    /* mut */
 304    is_dirty: bool,
 305    has_deleted_file: bool,
 306    has_conflict: bool,
 307    show_headers: bool,
 308}
 309
 310#[derive(Debug, Clone)]
 311enum DiffTransform {
 312    BufferContent {
 313        summary: TextSummary,
 314        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 315    },
 316    DeletedHunk {
 317        summary: TextSummary,
 318        buffer_id: BufferId,
 319        hunk_info: DiffTransformHunkInfo,
 320        base_text_byte_range: Range<usize>,
 321        has_trailing_newline: bool,
 322    },
 323}
 324
 325#[derive(Clone, Copy, Debug)]
 326struct DiffTransformHunkInfo {
 327    excerpt_id: ExcerptId,
 328    hunk_start_anchor: text::Anchor,
 329    hunk_secondary_status: DiffHunkSecondaryStatus,
 330}
 331
 332impl Eq for DiffTransformHunkInfo {}
 333
 334impl PartialEq for DiffTransformHunkInfo {
 335    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 336        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 337    }
 338}
 339
 340impl std::hash::Hash for DiffTransformHunkInfo {
 341    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 342        self.excerpt_id.hash(state);
 343        self.hunk_start_anchor.hash(state);
 344    }
 345}
 346
 347#[derive(Clone)]
 348pub struct ExcerptInfo {
 349    pub id: ExcerptId,
 350    pub buffer: BufferSnapshot,
 351    pub buffer_id: BufferId,
 352    pub range: ExcerptRange<text::Anchor>,
 353    pub end_row: MultiBufferRow,
 354}
 355
 356impl std::fmt::Debug for ExcerptInfo {
 357    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 358        f.debug_struct(type_name::<Self>())
 359            .field("id", &self.id)
 360            .field("buffer_id", &self.buffer_id)
 361            .field("path", &self.buffer.file().map(|f| f.path()))
 362            .field("range", &self.range)
 363            .finish()
 364    }
 365}
 366
 367/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 368#[derive(Debug)]
 369pub struct ExcerptBoundary {
 370    pub prev: Option<ExcerptInfo>,
 371    pub next: ExcerptInfo,
 372    /// The row in the `MultiBuffer` where the boundary is located
 373    pub row: MultiBufferRow,
 374}
 375
 376impl ExcerptBoundary {
 377    pub fn starts_new_buffer(&self) -> bool {
 378        match (self.prev.as_ref(), &self.next) {
 379            (None, _) => true,
 380            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 381        }
 382    }
 383}
 384
 385#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 386pub struct ExpandInfo {
 387    pub direction: ExpandExcerptDirection,
 388    pub excerpt_id: ExcerptId,
 389}
 390
 391#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 392pub struct RowInfo {
 393    pub buffer_id: Option<BufferId>,
 394    pub buffer_row: Option<u32>,
 395    pub multibuffer_row: Option<MultiBufferRow>,
 396    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 397    pub expand_info: Option<ExpandInfo>,
 398    pub wrapped: Option<u32>,
 399}
 400
 401/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 402#[derive(Clone)]
 403struct Excerpt {
 404    /// The unique identifier for this excerpt
 405    id: ExcerptId,
 406    /// The location of the excerpt in the [`MultiBuffer`]
 407    locator: Locator,
 408    /// The buffer being excerpted
 409    buffer_id: BufferId,
 410    /// A snapshot of the buffer being excerpted
 411    buffer: BufferSnapshot,
 412    /// The range of the buffer to be shown in the excerpt
 413    range: ExcerptRange<text::Anchor>,
 414    /// The last row in the excerpted slice of the buffer
 415    max_buffer_row: BufferRow,
 416    /// A summary of the text in the excerpt
 417    text_summary: TextSummary,
 418    has_trailing_newline: bool,
 419}
 420
 421/// A public view into an `Excerpt` in a [`MultiBuffer`].
 422///
 423/// Contains methods for getting the [`Buffer`] of the excerpt,
 424/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 425#[derive(Clone)]
 426pub struct MultiBufferExcerpt<'a> {
 427    excerpt: &'a Excerpt,
 428    diff_transforms: sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<usize>>,
 429    offset: usize,
 430    excerpt_offset: ExcerptDimension<usize>,
 431    buffer_offset: usize,
 432}
 433
 434#[derive(Clone, Debug)]
 435struct ExcerptIdMapping {
 436    id: ExcerptId,
 437    locator: Locator,
 438}
 439
 440/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 441/// These ranges are relative to the buffer itself
 442#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 443pub struct ExcerptRange<T> {
 444    /// The full range of text to be shown in the excerpt.
 445    pub context: Range<T>,
 446    /// The primary range of text to be highlighted in the excerpt.
 447    /// In a multi-buffer search, this would be the text that matched the search
 448    pub primary: Range<T>,
 449}
 450
 451impl<T: Clone> ExcerptRange<T> {
 452    pub fn new(context: Range<T>) -> Self {
 453        Self {
 454            context: context.clone(),
 455            primary: context,
 456        }
 457    }
 458}
 459
 460#[derive(Clone, Debug, Default)]
 461pub struct ExcerptSummary {
 462    excerpt_id: ExcerptId,
 463    /// The location of the last [`Excerpt`] being summarized
 464    excerpt_locator: Locator,
 465    widest_line_number: u32,
 466    text: TextSummary,
 467}
 468
 469#[derive(Debug, Clone)]
 470pub struct DiffTransformSummary {
 471    input: TextSummary,
 472    output: TextSummary,
 473}
 474
 475#[derive(Clone)]
 476pub struct MultiBufferRows<'a> {
 477    point: Point,
 478    is_empty: bool,
 479    is_singleton: bool,
 480    cursor: MultiBufferCursor<'a, Point>,
 481}
 482
 483pub struct MultiBufferChunks<'a> {
 484    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 485    diff_transforms: Cursor<'a, 'static, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 486    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 487    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 488    buffer_chunk: Option<Chunk<'a>>,
 489    range: Range<usize>,
 490    excerpt_offset_range: Range<ExcerptOffset>,
 491    excerpt_chunks: Option<ExcerptChunks<'a>>,
 492    language_aware: bool,
 493}
 494
 495pub struct ReversedMultiBufferChunks<'a> {
 496    cursor: MultiBufferCursor<'a, usize>,
 497    current_chunks: Option<rope::Chunks<'a>>,
 498    start: usize,
 499    offset: usize,
 500}
 501
 502pub struct MultiBufferBytes<'a> {
 503    range: Range<usize>,
 504    cursor: MultiBufferCursor<'a, usize>,
 505    excerpt_bytes: Option<text::Bytes<'a>>,
 506    has_trailing_newline: bool,
 507    chunk: &'a [u8],
 508}
 509
 510pub struct ReversedMultiBufferBytes<'a> {
 511    range: Range<usize>,
 512    chunks: ReversedMultiBufferChunks<'a>,
 513    chunk: &'a [u8],
 514}
 515
 516#[derive(Clone)]
 517struct DiffTransforms<D> {
 518    output_dimension: OutputDimension<D>,
 519    excerpt_dimension: ExcerptDimension<D>,
 520}
 521
 522impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 523    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 524        Self {
 525            output_dimension: OutputDimension::zero(cx),
 526            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 527                cx,
 528            ),
 529        }
 530    }
 531
 532    fn add_summary(
 533        &mut self,
 534        summary: &'a DiffTransformSummary,
 535        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 536    ) {
 537        self.output_dimension.add_summary(summary, cx);
 538        self.excerpt_dimension.add_summary(summary, cx);
 539    }
 540}
 541
 542#[derive(Clone)]
 543struct MultiBufferCursor<'a, D: TextDimension> {
 544    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<D>>,
 545    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<D>>,
 546    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 547    cached_region: Option<MultiBufferRegion<'a, D>>,
 548}
 549
 550#[derive(Clone)]
 551struct MultiBufferRegion<'a, D: TextDimension> {
 552    buffer: &'a BufferSnapshot,
 553    is_main_buffer: bool,
 554    diff_hunk_status: Option<DiffHunkStatus>,
 555    excerpt: &'a Excerpt,
 556    buffer_range: Range<D>,
 557    range: Range<D>,
 558    has_trailing_newline: bool,
 559}
 560
 561struct ExcerptChunks<'a> {
 562    excerpt_id: ExcerptId,
 563    content_chunks: BufferChunks<'a>,
 564    footer_height: usize,
 565}
 566
 567#[derive(Debug)]
 568struct BufferEdit {
 569    range: Range<usize>,
 570    new_text: Arc<str>,
 571    is_insertion: bool,
 572    original_indent_column: Option<u32>,
 573    excerpt_id: ExcerptId,
 574}
 575
 576#[derive(Clone, Copy, Debug, PartialEq)]
 577enum DiffChangeKind {
 578    BufferEdited,
 579    DiffUpdated { base_changed: bool },
 580    ExpandOrCollapseHunks { expand: bool },
 581}
 582
 583#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 584pub enum ExpandExcerptDirection {
 585    Up,
 586    Down,
 587    UpAndDown,
 588}
 589
 590impl ExpandExcerptDirection {
 591    pub fn should_expand_up(&self) -> bool {
 592        match self {
 593            ExpandExcerptDirection::Up => true,
 594            ExpandExcerptDirection::Down => false,
 595            ExpandExcerptDirection::UpAndDown => true,
 596        }
 597    }
 598
 599    pub fn should_expand_down(&self) -> bool {
 600        match self {
 601            ExpandExcerptDirection::Up => false,
 602            ExpandExcerptDirection::Down => true,
 603            ExpandExcerptDirection::UpAndDown => true,
 604        }
 605    }
 606}
 607
 608#[derive(Clone, Debug, PartialEq)]
 609pub struct IndentGuide {
 610    pub buffer_id: BufferId,
 611    pub start_row: MultiBufferRow,
 612    pub end_row: MultiBufferRow,
 613    pub depth: u32,
 614    pub tab_size: u32,
 615    pub settings: IndentGuideSettings,
 616}
 617
 618impl IndentGuide {
 619    pub fn indent_level(&self) -> u32 {
 620        self.depth * self.tab_size
 621    }
 622}
 623
 624impl MultiBuffer {
 625    pub fn new(capability: Capability) -> Self {
 626        Self::new_(
 627            capability,
 628            MultiBufferSnapshot {
 629                show_headers: true,
 630                ..MultiBufferSnapshot::default()
 631            },
 632        )
 633    }
 634
 635    pub fn without_headers(capability: Capability) -> Self {
 636        Self::new_(capability, Default::default())
 637    }
 638
 639    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 640        let mut this = Self::new_(
 641            buffer.read(cx).capability(),
 642            MultiBufferSnapshot {
 643                singleton: true,
 644                ..MultiBufferSnapshot::default()
 645            },
 646        );
 647        this.singleton = true;
 648        this.push_excerpts(
 649            buffer,
 650            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 651            cx,
 652        );
 653        this
 654    }
 655
 656    #[inline]
 657    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
 658        Self {
 659            snapshot: RefCell::new(snapshot),
 660            buffers: Default::default(),
 661            diffs: HashMap::default(),
 662            subscriptions: Topic::default(),
 663            singleton: false,
 664            capability,
 665            title: None,
 666            excerpts_by_path: Default::default(),
 667            paths_by_excerpt: Default::default(),
 668            buffer_changed_since_sync: Default::default(),
 669            history: History {
 670                next_transaction_id: clock::Lamport::MIN,
 671                undo_stack: Vec::new(),
 672                redo_stack: Vec::new(),
 673                transaction_depth: 0,
 674                group_interval: Duration::from_millis(300),
 675            },
 676        }
 677    }
 678
 679    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 680        let mut buffers = HashMap::default();
 681        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 682        for (buffer_id, buffer_state) in self.buffers.iter() {
 683            buffer_state.buffer.update(new_cx, |buffer, _| {
 684                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 685            });
 686            buffers.insert(
 687                *buffer_id,
 688                BufferState {
 689                    buffer: buffer_state.buffer.clone(),
 690                    last_version: buffer_state.last_version.clone(),
 691                    last_non_text_state_update_count: buffer_state
 692                        .last_non_text_state_update_count
 693                        .clone(),
 694                    excerpts: buffer_state.excerpts.clone(),
 695                    _subscriptions: [
 696                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 697                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 698                    ],
 699                },
 700            );
 701        }
 702        let mut diff_bases = HashMap::default();
 703        for (buffer_id, diff) in self.diffs.iter() {
 704            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 705        }
 706        Self {
 707            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 708            buffers: buffers,
 709            excerpts_by_path: Default::default(),
 710            paths_by_excerpt: Default::default(),
 711            diffs: diff_bases,
 712            subscriptions: Default::default(),
 713            singleton: self.singleton,
 714            capability: self.capability,
 715            history: self.history.clone(),
 716            title: self.title.clone(),
 717            buffer_changed_since_sync,
 718        }
 719    }
 720
 721    pub fn with_title(mut self, title: String) -> Self {
 722        self.title = Some(title);
 723        self
 724    }
 725
 726    pub fn read_only(&self) -> bool {
 727        self.capability == Capability::ReadOnly
 728    }
 729
 730    /// Returns an up-to-date snapshot of the MultiBuffer.
 731    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 732        self.sync(cx);
 733        self.snapshot.borrow().clone()
 734    }
 735
 736    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 737        self.sync(cx);
 738        self.snapshot.borrow()
 739    }
 740
 741    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 742        if self.singleton {
 743            Some(self.buffers.values().next().unwrap().buffer.clone())
 744        } else {
 745            None
 746        }
 747    }
 748
 749    pub fn is_singleton(&self) -> bool {
 750        self.singleton
 751    }
 752
 753    pub fn subscribe(&mut self) -> Subscription {
 754        self.subscriptions.subscribe()
 755    }
 756
 757    pub fn is_dirty(&self, cx: &App) -> bool {
 758        self.read(cx).is_dirty()
 759    }
 760
 761    pub fn has_deleted_file(&self, cx: &App) -> bool {
 762        self.read(cx).has_deleted_file()
 763    }
 764
 765    pub fn has_conflict(&self, cx: &App) -> bool {
 766        self.read(cx).has_conflict()
 767    }
 768
 769    // The `is_empty` signature doesn't match what clippy expects
 770    #[allow(clippy::len_without_is_empty)]
 771    pub fn len(&self, cx: &App) -> usize {
 772        self.read(cx).len()
 773    }
 774
 775    pub fn is_empty(&self) -> bool {
 776        self.buffers.is_empty()
 777    }
 778
 779    pub fn symbols_containing<T: ToOffset>(
 780        &self,
 781        offset: T,
 782        theme: Option<&SyntaxTheme>,
 783        cx: &App,
 784    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 785        self.read(cx).symbols_containing(offset, theme)
 786    }
 787
 788    pub fn edit<I, S, T>(
 789        &self,
 790        edits: I,
 791        autoindent_mode: Option<AutoindentMode>,
 792        cx: &mut Context<Self>,
 793    ) where
 794        I: IntoIterator<Item = (Range<S>, T)>,
 795        S: ToOffset,
 796        T: Into<Arc<str>>,
 797    {
 798        let snapshot = self.read(cx);
 799        let edits = edits
 800            .into_iter()
 801            .map(|(range, new_text)| {
 802                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 803                if range.start > range.end {
 804                    mem::swap(&mut range.start, &mut range.end);
 805                }
 806                (range, new_text.into())
 807            })
 808            .collect::<Vec<_>>();
 809
 810        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 811
 812        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 813        fn edit_internal(
 814            this: &MultiBuffer,
 815            snapshot: Ref<MultiBufferSnapshot>,
 816            edits: Vec<(Range<usize>, Arc<str>)>,
 817            mut autoindent_mode: Option<AutoindentMode>,
 818            cx: &mut Context<MultiBuffer>,
 819        ) {
 820            if this.read_only() || this.buffers.is_empty() {
 821                return;
 822            }
 823
 824            let original_indent_columns = match &mut autoindent_mode {
 825                Some(AutoindentMode::Block {
 826                    original_indent_columns,
 827                }) => mem::take(original_indent_columns),
 828                _ => Default::default(),
 829            };
 830
 831            let (buffer_edits, edited_excerpt_ids) =
 832                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 833            drop(snapshot);
 834
 835            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 836            for (buffer_id, mut edits) in buffer_edits {
 837                buffer_ids.push(buffer_id);
 838                edits.sort_by_key(|edit| edit.range.start);
 839                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
 840                    let mut edits = edits.into_iter().peekable();
 841                    let mut insertions = Vec::new();
 842                    let mut original_indent_columns = Vec::new();
 843                    let mut deletions = Vec::new();
 844                    let empty_str: Arc<str> = Arc::default();
 845                    while let Some(BufferEdit {
 846                        mut range,
 847                        mut new_text,
 848                        mut is_insertion,
 849                        original_indent_column,
 850                        excerpt_id,
 851                    }) = edits.next()
 852                    {
 853                        while let Some(BufferEdit {
 854                            range: next_range,
 855                            is_insertion: next_is_insertion,
 856                            new_text: next_new_text,
 857                            excerpt_id: next_excerpt_id,
 858                            ..
 859                        }) = edits.peek()
 860                        {
 861                            if range.end >= next_range.start {
 862                                range.end = cmp::max(next_range.end, range.end);
 863                                is_insertion |= *next_is_insertion;
 864                                if excerpt_id == *next_excerpt_id {
 865                                    new_text = format!("{new_text}{next_new_text}").into();
 866                                }
 867                                edits.next();
 868                            } else {
 869                                break;
 870                            }
 871                        }
 872
 873                        if is_insertion {
 874                            original_indent_columns.push(original_indent_column);
 875                            insertions.push((
 876                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 877                                new_text.clone(),
 878                            ));
 879                        } else if !range.is_empty() {
 880                            deletions.push((
 881                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 882                                empty_str.clone(),
 883                            ));
 884                        }
 885                    }
 886
 887                    let deletion_autoindent_mode =
 888                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 889                            Some(AutoindentMode::Block {
 890                                original_indent_columns: Default::default(),
 891                            })
 892                        } else {
 893                            autoindent_mode.clone()
 894                        };
 895                    let insertion_autoindent_mode =
 896                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 897                            Some(AutoindentMode::Block {
 898                                original_indent_columns,
 899                            })
 900                        } else {
 901                            autoindent_mode.clone()
 902                        };
 903
 904                    buffer.edit(deletions, deletion_autoindent_mode, cx);
 905                    buffer.edit(insertions, insertion_autoindent_mode, cx);
 906                })
 907            }
 908
 909            cx.emit(Event::ExcerptsEdited {
 910                excerpt_ids: edited_excerpt_ids,
 911                buffer_ids,
 912            });
 913        }
 914    }
 915
 916    fn convert_edits_to_buffer_edits(
 917        &self,
 918        edits: Vec<(Range<usize>, Arc<str>)>,
 919        snapshot: &MultiBufferSnapshot,
 920        original_indent_columns: &[Option<u32>],
 921    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 922        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 923        let mut edited_excerpt_ids = Vec::new();
 924        let mut cursor = snapshot.cursor::<usize>();
 925        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 926            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 927
 928            cursor.seek(&range.start);
 929            let mut start_region = cursor.region().expect("start offset out of bounds");
 930            if !start_region.is_main_buffer {
 931                cursor.next();
 932                if let Some(region) = cursor.region() {
 933                    start_region = region;
 934                } else {
 935                    continue;
 936                }
 937            }
 938
 939            if range.end < start_region.range.start {
 940                continue;
 941            }
 942
 943            if range.end > start_region.range.end {
 944                cursor.seek_forward(&range.end);
 945            }
 946            let mut end_region = cursor.region().expect("end offset out of bounds");
 947            if !end_region.is_main_buffer {
 948                cursor.prev();
 949                if let Some(region) = cursor.region() {
 950                    end_region = region;
 951                } else {
 952                    continue;
 953                }
 954            }
 955
 956            if range.start > end_region.range.end {
 957                continue;
 958            }
 959
 960            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 961            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 962            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 963                .min(start_region.buffer_range.end);
 964            let buffer_end =
 965                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 966
 967            if start_region.excerpt.id == end_region.excerpt.id {
 968                if start_region.is_main_buffer {
 969                    edited_excerpt_ids.push(start_region.excerpt.id);
 970                    buffer_edits
 971                        .entry(start_region.buffer.remote_id())
 972                        .or_default()
 973                        .push(BufferEdit {
 974                            range: buffer_start..buffer_end,
 975                            new_text,
 976                            is_insertion: true,
 977                            original_indent_column,
 978                            excerpt_id: start_region.excerpt.id,
 979                        });
 980                }
 981            } else {
 982                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 983                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 984                if start_region.is_main_buffer {
 985                    edited_excerpt_ids.push(start_region.excerpt.id);
 986                    buffer_edits
 987                        .entry(start_region.buffer.remote_id())
 988                        .or_default()
 989                        .push(BufferEdit {
 990                            range: start_excerpt_range,
 991                            new_text: new_text.clone(),
 992                            is_insertion: true,
 993                            original_indent_column,
 994                            excerpt_id: start_region.excerpt.id,
 995                        });
 996                }
 997                if end_region.is_main_buffer {
 998                    edited_excerpt_ids.push(end_region.excerpt.id);
 999                    buffer_edits
1000                        .entry(end_region.buffer.remote_id())
1001                        .or_default()
1002                        .push(BufferEdit {
1003                            range: end_excerpt_range,
1004                            new_text: new_text.clone(),
1005                            is_insertion: false,
1006                            original_indent_column,
1007                            excerpt_id: end_region.excerpt.id,
1008                        });
1009                }
1010
1011                cursor.seek(&range.start);
1012                cursor.next_excerpt();
1013                while let Some(region) = cursor.region() {
1014                    if region.excerpt.id == end_region.excerpt.id {
1015                        break;
1016                    }
1017                    if region.is_main_buffer {
1018                        edited_excerpt_ids.push(region.excerpt.id);
1019                        buffer_edits
1020                            .entry(region.buffer.remote_id())
1021                            .or_default()
1022                            .push(BufferEdit {
1023                                range: region.buffer_range,
1024                                new_text: new_text.clone(),
1025                                is_insertion: false,
1026                                original_indent_column,
1027                                excerpt_id: region.excerpt.id,
1028                            });
1029                    }
1030                    cursor.next_excerpt();
1031                }
1032            }
1033        }
1034        (buffer_edits, edited_excerpt_ids)
1035    }
1036
1037    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1038    where
1039        I: IntoIterator<Item = Range<S>>,
1040        S: ToOffset,
1041    {
1042        let snapshot = self.read(cx);
1043        let empty = Arc::<str>::from("");
1044        let edits = ranges
1045            .into_iter()
1046            .map(|range| {
1047                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1048                if range.start > range.end {
1049                    mem::swap(&mut range.start, &mut range.end);
1050                }
1051                (range, empty.clone())
1052            })
1053            .collect::<Vec<_>>();
1054
1055        return autoindent_ranges_internal(self, snapshot, edits, cx);
1056
1057        fn autoindent_ranges_internal(
1058            this: &MultiBuffer,
1059            snapshot: Ref<MultiBufferSnapshot>,
1060            edits: Vec<(Range<usize>, Arc<str>)>,
1061            cx: &mut Context<MultiBuffer>,
1062        ) {
1063            if this.read_only() || this.buffers.is_empty() {
1064                return;
1065            }
1066
1067            let (buffer_edits, edited_excerpt_ids) =
1068                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1069            drop(snapshot);
1070
1071            let mut buffer_ids = Vec::new();
1072            for (buffer_id, mut edits) in buffer_edits {
1073                buffer_ids.push(buffer_id);
1074                edits.sort_unstable_by_key(|edit| edit.range.start);
1075
1076                let mut ranges: Vec<Range<usize>> = Vec::new();
1077                for edit in edits {
1078                    if let Some(last_range) = ranges.last_mut()
1079                        && edit.range.start <= last_range.end
1080                    {
1081                        last_range.end = last_range.end.max(edit.range.end);
1082                        continue;
1083                    }
1084                    ranges.push(edit.range);
1085                }
1086
1087                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1088                    buffer.autoindent_ranges(ranges, cx);
1089                })
1090            }
1091
1092            cx.emit(Event::ExcerptsEdited {
1093                excerpt_ids: edited_excerpt_ids,
1094                buffer_ids,
1095            });
1096        }
1097    }
1098
1099    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1100    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1101    // Panics if the given position is invalid.
1102    pub fn insert_empty_line(
1103        &mut self,
1104        position: impl ToPoint,
1105        space_above: bool,
1106        space_below: bool,
1107        cx: &mut Context<Self>,
1108    ) -> Point {
1109        let multibuffer_point = position.to_point(&self.read(cx));
1110        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1111        self.start_transaction(cx);
1112        let empty_line_start = buffer.update(cx, |buffer, cx| {
1113            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1114        });
1115        self.end_transaction(cx);
1116        multibuffer_point + (empty_line_start - buffer_point)
1117    }
1118
1119    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1120        self.start_transaction_at(Instant::now(), cx)
1121    }
1122
1123    pub fn start_transaction_at(
1124        &mut self,
1125        now: Instant,
1126        cx: &mut Context<Self>,
1127    ) -> Option<TransactionId> {
1128        if let Some(buffer) = self.as_singleton() {
1129            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1130        }
1131
1132        for BufferState { buffer, .. } in self.buffers.values() {
1133            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1134        }
1135        self.history.start_transaction(now)
1136    }
1137
1138    pub fn last_transaction_id(&self, cx: &App) -> Option<TransactionId> {
1139        if let Some(buffer) = self.as_singleton() {
1140            buffer
1141                .read(cx)
1142                .peek_undo_stack()
1143                .map(|history_entry| history_entry.transaction_id())
1144        } else {
1145            let last_transaction = self.history.undo_stack.last()?;
1146            Some(last_transaction.id)
1147        }
1148    }
1149
1150    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1151        self.end_transaction_at(Instant::now(), cx)
1152    }
1153
1154    pub fn end_transaction_at(
1155        &mut self,
1156        now: Instant,
1157        cx: &mut Context<Self>,
1158    ) -> Option<TransactionId> {
1159        if let Some(buffer) = self.as_singleton() {
1160            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1161        }
1162
1163        let mut buffer_transactions = HashMap::default();
1164        for BufferState { buffer, .. } in self.buffers.values() {
1165            if let Some(transaction_id) =
1166                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1167            {
1168                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1169            }
1170        }
1171
1172        if self.history.end_transaction(now, buffer_transactions) {
1173            let transaction_id = self.history.group().unwrap();
1174            Some(transaction_id)
1175        } else {
1176            None
1177        }
1178    }
1179
1180    pub fn edited_ranges_for_transaction<D>(
1181        &self,
1182        transaction_id: TransactionId,
1183        cx: &App,
1184    ) -> Vec<Range<D>>
1185    where
1186        D: TextDimension + Ord + Sub<D, Output = D>,
1187    {
1188        let Some(transaction) = self.history.transaction(transaction_id) else {
1189            return Vec::new();
1190        };
1191
1192        let mut ranges = Vec::new();
1193        let snapshot = self.read(cx);
1194        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1195
1196        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1197            let Some(buffer_state) = self.buffers.get(buffer_id) else {
1198                continue;
1199            };
1200
1201            let buffer = buffer_state.buffer.read(cx);
1202            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1203                for excerpt_id in &buffer_state.excerpts {
1204                    cursor.seek(excerpt_id, Bias::Left);
1205                    if let Some(excerpt) = cursor.item()
1206                        && excerpt.locator == *excerpt_id
1207                    {
1208                        let excerpt_buffer_start = excerpt.range.context.start.summary::<D>(buffer);
1209                        let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1210                        let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1211                        if excerpt_range.contains(&range.start)
1212                            && excerpt_range.contains(&range.end)
1213                        {
1214                            let excerpt_start = D::from_text_summary(&cursor.start().text);
1215
1216                            let mut start = excerpt_start;
1217                            start.add_assign(&(range.start - excerpt_buffer_start));
1218                            let mut end = excerpt_start;
1219                            end.add_assign(&(range.end - excerpt_buffer_start));
1220
1221                            ranges.push(start..end);
1222                            break;
1223                        }
1224                    }
1225                }
1226            }
1227        }
1228
1229        ranges.sort_by_key(|range| range.start);
1230        ranges
1231    }
1232
1233    pub fn merge_transactions(
1234        &mut self,
1235        transaction: TransactionId,
1236        destination: TransactionId,
1237        cx: &mut Context<Self>,
1238    ) {
1239        if let Some(buffer) = self.as_singleton() {
1240            buffer.update(cx, |buffer, _| {
1241                buffer.merge_transactions(transaction, destination)
1242            });
1243        } else if let Some(transaction) = self.history.forget(transaction)
1244            && let Some(destination) = self.history.transaction_mut(destination)
1245        {
1246            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1247                if let Some(destination_buffer_transaction_id) =
1248                    destination.buffer_transactions.get(&buffer_id)
1249                {
1250                    if let Some(state) = self.buffers.get(&buffer_id) {
1251                        state.buffer.update(cx, |buffer, _| {
1252                            buffer.merge_transactions(
1253                                buffer_transaction_id,
1254                                *destination_buffer_transaction_id,
1255                            )
1256                        });
1257                    }
1258                } else {
1259                    destination
1260                        .buffer_transactions
1261                        .insert(buffer_id, buffer_transaction_id);
1262                }
1263            }
1264        }
1265    }
1266
1267    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1268        self.history.finalize_last_transaction();
1269        for BufferState { buffer, .. } in self.buffers.values() {
1270            buffer.update(cx, |buffer, _| {
1271                buffer.finalize_last_transaction();
1272            });
1273        }
1274    }
1275
1276    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1277    where
1278        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1279    {
1280        self.history
1281            .push_transaction(buffer_transactions, Instant::now(), cx);
1282        self.history.finalize_last_transaction();
1283    }
1284
1285    pub fn group_until_transaction(
1286        &mut self,
1287        transaction_id: TransactionId,
1288        cx: &mut Context<Self>,
1289    ) {
1290        if let Some(buffer) = self.as_singleton() {
1291            buffer.update(cx, |buffer, _| {
1292                buffer.group_until_transaction(transaction_id)
1293            });
1294        } else {
1295            self.history.group_until(transaction_id);
1296        }
1297    }
1298
1299    pub fn set_active_selections(
1300        &self,
1301        selections: &[Selection<Anchor>],
1302        line_mode: bool,
1303        cursor_shape: CursorShape,
1304        cx: &mut Context<Self>,
1305    ) {
1306        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1307            Default::default();
1308        let snapshot = self.read(cx);
1309        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1310        for selection in selections {
1311            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1312            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1313
1314            cursor.seek(&Some(start_locator), Bias::Left);
1315            while let Some(excerpt) = cursor.item()
1316                && excerpt.locator <= *end_locator
1317            {
1318                let mut start = excerpt.range.context.start;
1319                let mut end = excerpt.range.context.end;
1320                if excerpt.id == selection.start.excerpt_id {
1321                    start = selection.start.text_anchor;
1322                }
1323                if excerpt.id == selection.end.excerpt_id {
1324                    end = selection.end.text_anchor;
1325                }
1326                selections_by_buffer
1327                    .entry(excerpt.buffer_id)
1328                    .or_default()
1329                    .push(Selection {
1330                        id: selection.id,
1331                        start,
1332                        end,
1333                        reversed: selection.reversed,
1334                        goal: selection.goal,
1335                    });
1336
1337                cursor.next();
1338            }
1339        }
1340
1341        for (buffer_id, buffer_state) in self.buffers.iter() {
1342            if !selections_by_buffer.contains_key(buffer_id) {
1343                buffer_state
1344                    .buffer
1345                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1346            }
1347        }
1348
1349        for (buffer_id, mut selections) in selections_by_buffer {
1350            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1351                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1352                let mut selections = selections.into_iter().peekable();
1353                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1354                    let mut selection = selections.next()?;
1355                    while let Some(next_selection) = selections.peek() {
1356                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1357                            let next_selection = selections.next().unwrap();
1358                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1359                                selection.end = next_selection.end;
1360                            }
1361                        } else {
1362                            break;
1363                        }
1364                    }
1365                    Some(selection)
1366                }));
1367                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1368            });
1369        }
1370    }
1371
1372    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1373        for buffer in self.buffers.values() {
1374            buffer
1375                .buffer
1376                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1377        }
1378    }
1379
1380    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1381        let mut transaction_id = None;
1382        if let Some(buffer) = self.as_singleton() {
1383            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1384        } else {
1385            while let Some(transaction) = self.history.pop_undo() {
1386                let mut undone = false;
1387                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1388                    if let Some(BufferState { buffer, .. }) = self.buffers.get(buffer_id) {
1389                        undone |= buffer.update(cx, |buffer, cx| {
1390                            let undo_to = *buffer_transaction_id;
1391                            if let Some(entry) = buffer.peek_undo_stack() {
1392                                *buffer_transaction_id = entry.transaction_id();
1393                            }
1394                            buffer.undo_to_transaction(undo_to, cx)
1395                        });
1396                    }
1397                }
1398
1399                if undone {
1400                    transaction_id = Some(transaction.id);
1401                    break;
1402                }
1403            }
1404        }
1405
1406        if let Some(transaction_id) = transaction_id {
1407            cx.emit(Event::TransactionUndone { transaction_id });
1408        }
1409
1410        transaction_id
1411    }
1412
1413    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1414        if let Some(buffer) = self.as_singleton() {
1415            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1416        }
1417
1418        while let Some(transaction) = self.history.pop_redo() {
1419            let mut redone = false;
1420            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1421                if let Some(BufferState { buffer, .. }) = self.buffers.get(buffer_id) {
1422                    redone |= buffer.update(cx, |buffer, cx| {
1423                        let redo_to = *buffer_transaction_id;
1424                        if let Some(entry) = buffer.peek_redo_stack() {
1425                            *buffer_transaction_id = entry.transaction_id();
1426                        }
1427                        buffer.redo_to_transaction(redo_to, cx)
1428                    });
1429                }
1430            }
1431
1432            if redone {
1433                return Some(transaction.id);
1434            }
1435        }
1436
1437        None
1438    }
1439
1440    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1441        if let Some(buffer) = self.as_singleton() {
1442            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1443        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1444            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1445                if let Some(BufferState { buffer, .. }) = self.buffers.get(buffer_id) {
1446                    buffer.update(cx, |buffer, cx| {
1447                        buffer.undo_transaction(*transaction_id, cx)
1448                    });
1449                }
1450            }
1451        }
1452    }
1453
1454    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1455        if let Some(buffer) = self.as_singleton() {
1456            buffer.update(cx, |buffer, _| {
1457                buffer.forget_transaction(transaction_id);
1458            });
1459        } else if let Some(transaction) = self.history.forget(transaction_id) {
1460            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1461                if let Some(state) = self.buffers.get_mut(&buffer_id) {
1462                    state.buffer.update(cx, |buffer, _| {
1463                        buffer.forget_transaction(buffer_transaction_id);
1464                    });
1465                }
1466            }
1467        }
1468    }
1469
1470    pub fn push_excerpts<O>(
1471        &mut self,
1472        buffer: Entity<Buffer>,
1473        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1474        cx: &mut Context<Self>,
1475    ) -> Vec<ExcerptId>
1476    where
1477        O: text::ToOffset,
1478    {
1479        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1480    }
1481
1482    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1483        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1484        let snapshot = self.snapshot(cx);
1485        let excerpt = snapshot.excerpt(*excerpt_id)?;
1486        Some(Anchor::in_buffer(
1487            *excerpt_id,
1488            excerpt.buffer_id,
1489            excerpt.range.context.start,
1490        ))
1491    }
1492
1493    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1494        self.excerpts_by_path.keys()
1495    }
1496
1497    fn expand_excerpts_with_paths(
1498        &mut self,
1499        ids: impl IntoIterator<Item = ExcerptId>,
1500        line_count: u32,
1501        direction: ExpandExcerptDirection,
1502        cx: &mut Context<Self>,
1503    ) {
1504        let grouped = ids
1505            .into_iter()
1506            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1507            .into_iter()
1508            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1509            .collect::<Vec<_>>();
1510        let snapshot = self.snapshot(cx);
1511
1512        for (path, ids) in grouped.into_iter() {
1513            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1514                continue;
1515            };
1516
1517            let ids_to_expand = HashSet::from_iter(ids);
1518            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1519                let excerpt = snapshot.excerpt(*excerpt_id)?;
1520
1521                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1522                if ids_to_expand.contains(excerpt_id) {
1523                    match direction {
1524                        ExpandExcerptDirection::Up => {
1525                            context.start.row = context.start.row.saturating_sub(line_count);
1526                            context.start.column = 0;
1527                        }
1528                        ExpandExcerptDirection::Down => {
1529                            context.end.row =
1530                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1531                            context.end.column = excerpt.buffer.line_len(context.end.row);
1532                        }
1533                        ExpandExcerptDirection::UpAndDown => {
1534                            context.start.row = context.start.row.saturating_sub(line_count);
1535                            context.start.column = 0;
1536                            context.end.row =
1537                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1538                            context.end.column = excerpt.buffer.line_len(context.end.row);
1539                        }
1540                    }
1541                }
1542
1543                Some(ExcerptRange {
1544                    context,
1545                    primary: excerpt.range.primary.to_point(&excerpt.buffer),
1546                })
1547            });
1548            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1549            for range in expanded_ranges {
1550                if let Some(last_range) = merged_ranges.last_mut()
1551                    && last_range.context.end >= range.context.start
1552                {
1553                    last_range.context.end = range.context.end;
1554                    continue;
1555                }
1556                merged_ranges.push(range)
1557            }
1558            let Some(excerpt_id) = excerpt_ids.first() else {
1559                continue;
1560            };
1561            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1562                continue;
1563            };
1564
1565            let Some(buffer) = self.buffers.get(buffer_id).map(|b| b.buffer.clone()) else {
1566                continue;
1567            };
1568
1569            let buffer_snapshot = buffer.read(cx).snapshot();
1570            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1571        }
1572    }
1573
1574    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1575    pub fn set_excerpts_for_path(
1576        &mut self,
1577        path: PathKey,
1578        buffer: Entity<Buffer>,
1579        ranges: impl IntoIterator<Item = Range<Point>>,
1580        context_line_count: u32,
1581        cx: &mut Context<Self>,
1582    ) -> (Vec<Range<Anchor>>, bool) {
1583        let buffer_snapshot = buffer.read(cx).snapshot();
1584        let excerpt_ranges = build_excerpt_ranges(ranges, context_line_count, &buffer_snapshot);
1585
1586        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1587        self.set_merged_excerpt_ranges_for_path(
1588            path,
1589            buffer,
1590            excerpt_ranges,
1591            &buffer_snapshot,
1592            new,
1593            counts,
1594            cx,
1595        )
1596    }
1597
1598    pub fn set_excerpt_ranges_for_path(
1599        &mut self,
1600        path: PathKey,
1601        buffer: Entity<Buffer>,
1602        buffer_snapshot: &BufferSnapshot,
1603        excerpt_ranges: Vec<ExcerptRange<Point>>,
1604        cx: &mut Context<Self>,
1605    ) -> (Vec<Range<Anchor>>, bool) {
1606        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1607        self.set_merged_excerpt_ranges_for_path(
1608            path,
1609            buffer,
1610            excerpt_ranges,
1611            buffer_snapshot,
1612            new,
1613            counts,
1614            cx,
1615        )
1616    }
1617
1618    pub fn set_anchored_excerpts_for_path(
1619        &self,
1620        path_key: PathKey,
1621        buffer: Entity<Buffer>,
1622        ranges: Vec<Range<text::Anchor>>,
1623        context_line_count: u32,
1624        cx: &mut Context<Self>,
1625    ) -> Task<Vec<Range<Anchor>>> {
1626        let buffer_snapshot = buffer.read(cx).snapshot();
1627        cx.spawn(async move |multi_buffer, cx| {
1628            let snapshot = buffer_snapshot.clone();
1629            let (excerpt_ranges, new, counts) = cx
1630                .background_spawn(async move {
1631                    let ranges = ranges.into_iter().map(|range| range.to_point(&snapshot));
1632                    let excerpt_ranges =
1633                        build_excerpt_ranges(ranges, context_line_count, &snapshot);
1634                    let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1635                    (excerpt_ranges, new, counts)
1636                })
1637                .await;
1638
1639            multi_buffer
1640                .update(cx, move |multi_buffer, cx| {
1641                    let (ranges, _) = multi_buffer.set_merged_excerpt_ranges_for_path(
1642                        path_key,
1643                        buffer,
1644                        excerpt_ranges,
1645                        &buffer_snapshot,
1646                        new,
1647                        counts,
1648                        cx,
1649                    );
1650                    ranges
1651                })
1652                .ok()
1653                .unwrap_or_default()
1654        })
1655    }
1656
1657    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1658    fn set_merged_excerpt_ranges_for_path(
1659        &mut self,
1660        path: PathKey,
1661        buffer: Entity<Buffer>,
1662        ranges: Vec<ExcerptRange<Point>>,
1663        buffer_snapshot: &BufferSnapshot,
1664        new: Vec<ExcerptRange<Point>>,
1665        counts: Vec<usize>,
1666        cx: &mut Context<Self>,
1667    ) -> (Vec<Range<Anchor>>, bool) {
1668        let (excerpt_ids, added_a_new_excerpt) =
1669            self.update_path_excerpts(path, buffer, buffer_snapshot, new, cx);
1670
1671        let mut result = Vec::new();
1672        let mut ranges = ranges.into_iter();
1673        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(counts.into_iter()) {
1674            for range in ranges.by_ref().take(range_count) {
1675                let range = Anchor::range_in_buffer(
1676                    excerpt_id,
1677                    buffer_snapshot.remote_id(),
1678                    buffer_snapshot.anchor_before(&range.primary.start)
1679                        ..buffer_snapshot.anchor_after(&range.primary.end),
1680                );
1681                result.push(range)
1682            }
1683        }
1684        (result, added_a_new_excerpt)
1685    }
1686
1687    fn merge_excerpt_ranges<'a>(
1688        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1689    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1690        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1691        let mut counts: Vec<usize> = Vec::new();
1692        for range in expanded_ranges {
1693            if let Some(last_range) = merged_ranges.last_mut() {
1694                debug_assert!(
1695                    last_range.context.start <= range.context.start,
1696                    "Last range: {last_range:?} Range: {range:?}"
1697                );
1698                if last_range.context.end >= range.context.start
1699                    || last_range.context.end.row + 1 == range.context.start.row
1700                {
1701                    last_range.context.end = range.context.end.max(last_range.context.end);
1702                    *counts.last_mut().unwrap() += 1;
1703                    continue;
1704                }
1705            }
1706            merged_ranges.push(range.clone());
1707            counts.push(1);
1708        }
1709        (merged_ranges, counts)
1710    }
1711
1712    fn update_path_excerpts(
1713        &mut self,
1714        path: PathKey,
1715        buffer: Entity<Buffer>,
1716        buffer_snapshot: &BufferSnapshot,
1717        new: Vec<ExcerptRange<Point>>,
1718        cx: &mut Context<Self>,
1719    ) -> (Vec<ExcerptId>, bool) {
1720        let mut insert_after = self
1721            .excerpts_by_path
1722            .range(..path.clone())
1723            .next_back()
1724            .map(|(_, value)| *value.last().unwrap())
1725            .unwrap_or(ExcerptId::min());
1726
1727        let existing = self
1728            .excerpts_by_path
1729            .get(&path)
1730            .cloned()
1731            .unwrap_or_default();
1732
1733        let mut new_iter = new.into_iter().peekable();
1734        let mut existing_iter = existing.into_iter().peekable();
1735
1736        let mut excerpt_ids = Vec::new();
1737        let mut to_remove = Vec::new();
1738        let mut to_insert: Vec<(ExcerptId, ExcerptRange<Point>)> = Vec::new();
1739        let mut added_a_new_excerpt = false;
1740        let snapshot = self.snapshot(cx);
1741
1742        let mut next_excerpt_id =
1743            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1744                last_entry.id.0 + 1
1745            } else {
1746                1
1747            };
1748
1749        let mut next_excerpt_id = move || ExcerptId(post_inc(&mut next_excerpt_id));
1750
1751        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1752        excerpts_cursor.next();
1753
1754        loop {
1755            let new = new_iter.peek();
1756            let existing = if let Some(existing_id) = existing_iter.peek() {
1757                let locator = snapshot.excerpt_locator_for_id(*existing_id);
1758                excerpts_cursor.seek_forward(&Some(locator), Bias::Left);
1759                if let Some(excerpt) = excerpts_cursor.item() {
1760                    if excerpt.buffer_id != buffer_snapshot.remote_id() {
1761                        to_remove.push(*existing_id);
1762                        existing_iter.next();
1763                        continue;
1764                    }
1765                    Some((
1766                        *existing_id,
1767                        excerpt.range.context.to_point(buffer_snapshot),
1768                    ))
1769                } else {
1770                    None
1771                }
1772            } else {
1773                None
1774            };
1775
1776            if let Some((last_id, last)) = to_insert.last_mut() {
1777                if let Some(new) = new
1778                    && last.context.end >= new.context.start
1779                {
1780                    last.context.end = last.context.end.max(new.context.end);
1781                    excerpt_ids.push(*last_id);
1782                    new_iter.next();
1783                    continue;
1784                }
1785                if let Some((existing_id, existing_range)) = &existing
1786                    && last.context.end >= existing_range.start
1787                {
1788                    last.context.end = last.context.end.max(existing_range.end);
1789                    to_remove.push(*existing_id);
1790                    self.snapshot
1791                        .get_mut()
1792                        .replaced_excerpts
1793                        .insert(*existing_id, *last_id);
1794                    existing_iter.next();
1795                    continue;
1796                }
1797            }
1798
1799            match (new, existing) {
1800                (None, None) => break,
1801                (None, Some((existing_id, _))) => {
1802                    existing_iter.next();
1803                    to_remove.push(existing_id);
1804                    continue;
1805                }
1806                (Some(_), None) => {
1807                    added_a_new_excerpt = true;
1808                    let new_id = next_excerpt_id();
1809                    excerpt_ids.push(new_id);
1810                    to_insert.push((new_id, new_iter.next().unwrap()));
1811                    continue;
1812                }
1813                (Some(new), Some((_, existing_range))) => {
1814                    if existing_range.end < new.context.start {
1815                        let existing_id = existing_iter.next().unwrap();
1816                        to_remove.push(existing_id);
1817                        continue;
1818                    } else if existing_range.start > new.context.end {
1819                        let new_id = next_excerpt_id();
1820                        excerpt_ids.push(new_id);
1821                        to_insert.push((new_id, new_iter.next().unwrap()));
1822                        continue;
1823                    }
1824
1825                    if existing_range.start == new.context.start
1826                        && existing_range.end == new.context.end
1827                    {
1828                        self.insert_excerpts_with_ids_after(
1829                            insert_after,
1830                            buffer.clone(),
1831                            mem::take(&mut to_insert),
1832                            cx,
1833                        );
1834                        insert_after = existing_iter.next().unwrap();
1835                        excerpt_ids.push(insert_after);
1836                        new_iter.next();
1837                    } else {
1838                        let existing_id = existing_iter.next().unwrap();
1839                        let new_id = next_excerpt_id();
1840                        self.snapshot
1841                            .get_mut()
1842                            .replaced_excerpts
1843                            .insert(existing_id, new_id);
1844                        to_remove.push(existing_id);
1845                        let mut range = new_iter.next().unwrap();
1846                        range.context.start = range.context.start.min(existing_range.start);
1847                        range.context.end = range.context.end.max(existing_range.end);
1848                        excerpt_ids.push(new_id);
1849                        to_insert.push((new_id, range));
1850                    }
1851                }
1852            };
1853        }
1854
1855        self.insert_excerpts_with_ids_after(insert_after, buffer, to_insert, cx);
1856        self.remove_excerpts(to_remove, cx);
1857        if excerpt_ids.is_empty() {
1858            self.excerpts_by_path.remove(&path);
1859        } else {
1860            for excerpt_id in &excerpt_ids {
1861                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1862            }
1863            self.excerpts_by_path
1864                .insert(path, excerpt_ids.iter().dedup().cloned().collect());
1865        }
1866
1867        (excerpt_ids, added_a_new_excerpt)
1868    }
1869
1870    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1871        self.excerpts_by_path.keys().cloned()
1872    }
1873
1874    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1875        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1876            self.remove_excerpts(to_remove, cx)
1877        }
1878    }
1879
1880    pub fn insert_excerpts_after<O>(
1881        &mut self,
1882        prev_excerpt_id: ExcerptId,
1883        buffer: Entity<Buffer>,
1884        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1885        cx: &mut Context<Self>,
1886    ) -> Vec<ExcerptId>
1887    where
1888        O: text::ToOffset,
1889    {
1890        let mut ids = Vec::new();
1891        let mut next_excerpt_id =
1892            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1893                last_entry.id.0 + 1
1894            } else {
1895                1
1896            };
1897        self.insert_excerpts_with_ids_after(
1898            prev_excerpt_id,
1899            buffer,
1900            ranges.into_iter().map(|range| {
1901                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1902                ids.push(id);
1903                (id, range)
1904            }),
1905            cx,
1906        );
1907        ids
1908    }
1909
1910    pub fn insert_excerpts_with_ids_after<O>(
1911        &mut self,
1912        prev_excerpt_id: ExcerptId,
1913        buffer: Entity<Buffer>,
1914        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1915        cx: &mut Context<Self>,
1916    ) where
1917        O: text::ToOffset,
1918    {
1919        assert_eq!(self.history.transaction_depth, 0);
1920        let mut ranges = ranges.into_iter().peekable();
1921        if ranges.peek().is_none() {
1922            return Default::default();
1923        }
1924
1925        self.sync(cx);
1926
1927        let buffer_snapshot = buffer.read(cx).snapshot();
1928        let buffer_id = buffer_snapshot.remote_id();
1929
1930        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1931            self.buffer_changed_since_sync.replace(true);
1932            buffer.update(cx, |buffer, _| {
1933                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1934            });
1935            BufferState {
1936                last_version: RefCell::new(buffer_snapshot.version().clone()),
1937                last_non_text_state_update_count: Cell::new(
1938                    buffer_snapshot.non_text_state_update_count(),
1939                ),
1940                excerpts: Default::default(),
1941                _subscriptions: [
1942                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1943                    cx.subscribe(&buffer, Self::on_buffer_event),
1944                ],
1945                buffer: buffer.clone(),
1946            }
1947        });
1948
1949        let mut snapshot = self.snapshot.get_mut();
1950
1951        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1952        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1953        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1954        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1955        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1956
1957        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1958        new_excerpts.update_last(
1959            |excerpt| {
1960                excerpt.has_trailing_newline = true;
1961            },
1962            (),
1963        );
1964
1965        let next_locator = if let Some(excerpt) = cursor.item() {
1966            excerpt.locator.clone()
1967        } else {
1968            Locator::max()
1969        };
1970
1971        let mut excerpts = Vec::new();
1972        while let Some((id, range)) = ranges.next() {
1973            let locator = Locator::between(&prev_locator, &next_locator);
1974            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1975                buffer_state.excerpts.insert(ix, locator.clone());
1976            }
1977            let range = ExcerptRange {
1978                context: buffer_snapshot.anchor_before(&range.context.start)
1979                    ..buffer_snapshot.anchor_after(&range.context.end),
1980                primary: buffer_snapshot.anchor_before(&range.primary.start)
1981                    ..buffer_snapshot.anchor_after(&range.primary.end),
1982            };
1983            excerpts.push((id, range.clone()));
1984            let excerpt = Excerpt::new(
1985                id,
1986                locator.clone(),
1987                buffer_id,
1988                buffer_snapshot.clone(),
1989                range,
1990                ranges.peek().is_some() || cursor.item().is_some(),
1991            );
1992            new_excerpts.push(excerpt, ());
1993            prev_locator = locator.clone();
1994
1995            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1996                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1997            }
1998            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1999        }
2000
2001        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
2002
2003        let suffix = cursor.suffix();
2004        let changed_trailing_excerpt = suffix.is_empty();
2005        new_excerpts.append(suffix, ());
2006        drop(cursor);
2007        snapshot.excerpts = new_excerpts;
2008        snapshot.excerpt_ids = new_excerpt_ids;
2009        if changed_trailing_excerpt {
2010            snapshot.trailing_excerpt_update_count += 1;
2011        }
2012
2013        let edits = Self::sync_diff_transforms(
2014            &mut snapshot,
2015            vec![Edit {
2016                old: edit_start..edit_start,
2017                new: edit_start..edit_end,
2018            }],
2019            DiffChangeKind::BufferEdited,
2020        );
2021        if !edits.is_empty() {
2022            self.subscriptions.publish(edits);
2023        }
2024
2025        cx.emit(Event::Edited {
2026            edited_buffer: None,
2027        });
2028        cx.emit(Event::ExcerptsAdded {
2029            buffer,
2030            predecessor: prev_excerpt_id,
2031            excerpts,
2032        });
2033        cx.notify();
2034    }
2035
2036    pub fn clear(&mut self, cx: &mut Context<Self>) {
2037        self.sync(cx);
2038        let ids = self.excerpt_ids();
2039        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
2040        self.excerpts_by_path.clear();
2041        self.paths_by_excerpt.clear();
2042        let mut snapshot = self.snapshot.get_mut();
2043        let start = ExcerptOffset::new(0);
2044        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2045        snapshot.excerpts = Default::default();
2046        snapshot.trailing_excerpt_update_count += 1;
2047        snapshot.is_dirty = false;
2048        snapshot.has_deleted_file = false;
2049        snapshot.has_conflict = false;
2050        snapshot.replaced_excerpts.clear();
2051
2052        let edits = Self::sync_diff_transforms(
2053            &mut snapshot,
2054            vec![Edit {
2055                old: start..prev_len,
2056                new: start..start,
2057            }],
2058            DiffChangeKind::BufferEdited,
2059        );
2060        if !edits.is_empty() {
2061            self.subscriptions.publish(edits);
2062        }
2063        cx.emit(Event::Edited {
2064            edited_buffer: None,
2065        });
2066        cx.emit(Event::ExcerptsRemoved {
2067            ids,
2068            removed_buffer_ids,
2069        });
2070        cx.notify();
2071    }
2072
2073    pub fn excerpts_for_buffer(
2074        &self,
2075        buffer_id: BufferId,
2076        cx: &App,
2077    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2078        let mut excerpts = Vec::new();
2079        let snapshot = self.read(cx);
2080        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
2081        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
2082            for locator in locators {
2083                cursor.seek_forward(&Some(locator), Bias::Left);
2084                if let Some(excerpt) = cursor.item()
2085                    && excerpt.locator == *locator
2086                {
2087                    excerpts.push((excerpt.id, excerpt.range.clone()));
2088                }
2089            }
2090        }
2091
2092        excerpts
2093    }
2094
2095    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2096        let snapshot = self.read(cx);
2097        let mut excerpts = snapshot
2098            .excerpts
2099            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
2100        let mut diff_transforms = snapshot
2101            .diff_transforms
2102            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
2103        diff_transforms.next();
2104        let locators = self
2105            .buffers
2106            .get(&buffer_id)
2107            .into_iter()
2108            .flat_map(|state| &state.excerpts);
2109        let mut result = Vec::new();
2110        for locator in locators {
2111            excerpts.seek_forward(&Some(locator), Bias::Left);
2112            if let Some(excerpt) = excerpts.item()
2113                && excerpt.locator == *locator
2114            {
2115                let excerpt_start = excerpts.start().1.clone();
2116                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2117
2118                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2119                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2120                let start = diff_transforms.start().1.0 + overshoot;
2121
2122                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2123                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2124                let end = diff_transforms.start().1.0 + overshoot;
2125
2126                result.push(start..end)
2127            }
2128        }
2129        result
2130    }
2131
2132    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2133        self.snapshot
2134            .borrow()
2135            .excerpts
2136            .iter()
2137            .map(|entry| entry.buffer_id)
2138            .collect()
2139    }
2140
2141    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2142        self.snapshot
2143            .borrow()
2144            .excerpts
2145            .iter()
2146            .map(|entry| entry.id)
2147            .collect()
2148    }
2149
2150    pub fn excerpt_containing(
2151        &self,
2152        position: impl ToOffset,
2153        cx: &App,
2154    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2155        let snapshot = self.read(cx);
2156        let offset = position.to_offset(&snapshot);
2157
2158        let mut cursor = snapshot.cursor::<usize>();
2159        cursor.seek(&offset);
2160        cursor
2161            .excerpt()
2162            .or_else(|| snapshot.excerpts.last())
2163            .map(|excerpt| {
2164                (
2165                    excerpt.id,
2166                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2167                    excerpt.range.context.clone(),
2168                )
2169            })
2170    }
2171
2172    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2173        if let Some(buffer_id) = anchor.buffer_id {
2174            self.buffer(buffer_id)
2175        } else {
2176            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2177            Some(buffer)
2178        }
2179    }
2180
2181    // If point is at the end of the buffer, the last excerpt is returned
2182    pub fn point_to_buffer_offset<T: ToOffset>(
2183        &self,
2184        point: T,
2185        cx: &App,
2186    ) -> Option<(Entity<Buffer>, usize)> {
2187        let snapshot = self.read(cx);
2188        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2189        Some((
2190            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2191            offset,
2192        ))
2193    }
2194
2195    // If point is at the end of the buffer, the last excerpt is returned
2196    pub fn point_to_buffer_point<T: ToPoint>(
2197        &self,
2198        point: T,
2199        cx: &App,
2200    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2201        let snapshot = self.read(cx);
2202        let (buffer, point, is_main_buffer) =
2203            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2204        Some((
2205            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2206            point,
2207            is_main_buffer,
2208        ))
2209    }
2210
2211    pub fn buffer_point_to_anchor(
2212        &self,
2213        buffer: &Entity<Buffer>,
2214        point: Point,
2215        cx: &App,
2216    ) -> Option<Anchor> {
2217        let mut found = None;
2218        let snapshot = buffer.read(cx).snapshot();
2219        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2220            let start = range.context.start.to_point(&snapshot);
2221            let end = range.context.end.to_point(&snapshot);
2222            if start <= point && point < end {
2223                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2224                break;
2225            }
2226            if point < start {
2227                found = Some((start, excerpt_id));
2228            }
2229            if point > end {
2230                found = Some((end, excerpt_id));
2231            }
2232        }
2233
2234        found.map(|(point, excerpt_id)| {
2235            let text_anchor = snapshot.anchor_after(point);
2236            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2237        })
2238    }
2239
2240    pub fn remove_excerpts(
2241        &mut self,
2242        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2243        cx: &mut Context<Self>,
2244    ) {
2245        self.sync(cx);
2246        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2247        if ids.is_empty() {
2248            return;
2249        }
2250
2251        let mut snapshot = self.snapshot.get_mut();
2252        let mut new_excerpts = SumTree::default();
2253        let mut cursor = snapshot
2254            .excerpts
2255            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2256        let mut edits = Vec::new();
2257        let mut excerpt_ids = ids.iter().copied().peekable();
2258        let mut removed_buffer_ids = Vec::new();
2259
2260        while let Some(excerpt_id) = excerpt_ids.next() {
2261            self.paths_by_excerpt.remove(&excerpt_id);
2262            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2263            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2264            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2265
2266            if let Some(mut excerpt) = cursor.item() {
2267                if excerpt.id != excerpt_id {
2268                    continue;
2269                }
2270                let mut old_start = cursor.start().1;
2271
2272                // Skip over the removed excerpt.
2273                'remove_excerpts: loop {
2274                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2275                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2276                        if buffer_state.excerpts.is_empty() {
2277                            log::debug!(
2278                                "removing buffer and diff for buffer {}",
2279                                excerpt.buffer_id
2280                            );
2281                            self.buffers.remove(&excerpt.buffer_id);
2282                            removed_buffer_ids.push(excerpt.buffer_id);
2283                        }
2284                    }
2285                    cursor.next();
2286
2287                    // Skip over any subsequent excerpts that are also removed.
2288                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2289                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2290                        if let Some(next_excerpt) = cursor.item()
2291                            && next_excerpt.locator == *next_locator
2292                        {
2293                            excerpt_ids.next();
2294                            excerpt = next_excerpt;
2295                            continue 'remove_excerpts;
2296                        }
2297                    }
2298
2299                    break;
2300                }
2301
2302                // When removing the last excerpt, remove the trailing newline from
2303                // the previous excerpt.
2304                if cursor.item().is_none() && old_start.value > 0 {
2305                    old_start.value -= 1;
2306                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2307                }
2308
2309                // Push an edit for the removal of this run of excerpts.
2310                let old_end = cursor.start().1;
2311                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2312                edits.push(Edit {
2313                    old: old_start..old_end,
2314                    new: new_start..new_start,
2315                });
2316            }
2317        }
2318        let suffix = cursor.suffix();
2319        let changed_trailing_excerpt = suffix.is_empty();
2320        new_excerpts.append(suffix, ());
2321        drop(cursor);
2322        snapshot.excerpts = new_excerpts;
2323        for buffer_id in &removed_buffer_ids {
2324            self.diffs.remove(buffer_id);
2325            snapshot.diffs.remove(buffer_id);
2326        }
2327
2328        if changed_trailing_excerpt {
2329            snapshot.trailing_excerpt_update_count += 1;
2330        }
2331
2332        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2333        if !edits.is_empty() {
2334            self.subscriptions.publish(edits);
2335        }
2336        self.buffer_changed_since_sync.replace(true);
2337        cx.emit(Event::Edited {
2338            edited_buffer: None,
2339        });
2340        cx.emit(Event::ExcerptsRemoved {
2341            ids,
2342            removed_buffer_ids,
2343        });
2344        cx.notify();
2345    }
2346
2347    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2348        &self,
2349        anchors: Anchors,
2350        cx: &mut Context<Self>,
2351    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2352        let mut error = None;
2353        let mut futures = Vec::new();
2354        for anchor in anchors {
2355            if let Some(buffer_id) = anchor.buffer_id {
2356                if let Some(buffer) = self.buffers.get(&buffer_id) {
2357                    buffer.buffer.update(cx, |buffer, _| {
2358                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2359                    });
2360                } else {
2361                    error = Some(anyhow!(
2362                        "buffer {buffer_id} is not part of this multi-buffer"
2363                    ));
2364                    break;
2365                }
2366            }
2367        }
2368        async move {
2369            if let Some(error) = error {
2370                Err(error)?;
2371            }
2372            for future in futures {
2373                future.await?;
2374            }
2375            Ok(())
2376        }
2377    }
2378
2379    pub fn text_anchor_for_position<T: ToOffset>(
2380        &self,
2381        position: T,
2382        cx: &App,
2383    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2384        let snapshot = self.read(cx);
2385        let anchor = snapshot.anchor_before(position);
2386        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
2387        Some((buffer, anchor.text_anchor))
2388    }
2389
2390    fn on_buffer_event(
2391        &mut self,
2392        buffer: Entity<Buffer>,
2393        event: &language::BufferEvent,
2394        cx: &mut Context<Self>,
2395    ) {
2396        use language::BufferEvent;
2397        cx.emit(match event {
2398            BufferEvent::Edited => Event::Edited {
2399                edited_buffer: Some(buffer),
2400            },
2401            BufferEvent::DirtyChanged => Event::DirtyChanged,
2402            BufferEvent::Saved => Event::Saved,
2403            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2404            BufferEvent::Reloaded => Event::Reloaded,
2405            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2406            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2407            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2408            BufferEvent::CapabilityChanged => {
2409                self.capability = buffer.read(cx).capability();
2410                return;
2411            }
2412            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2413        });
2414    }
2415
2416    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2417        self.sync(cx);
2418        let snapshot = self.snapshot.get_mut();
2419        let diff = diff.read(cx);
2420        let buffer_id = diff.buffer_id;
2421        let diff = diff.snapshot(cx);
2422        snapshot.diffs.insert(buffer_id, diff);
2423    }
2424
2425    fn buffer_diff_changed(
2426        &mut self,
2427        diff: Entity<BufferDiff>,
2428        range: Range<text::Anchor>,
2429        cx: &mut Context<Self>,
2430    ) {
2431        self.sync(cx);
2432        self.buffer_changed_since_sync.replace(true);
2433
2434        let diff = diff.read(cx);
2435        let buffer_id = diff.buffer_id;
2436        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2437            return;
2438        };
2439
2440        let buffer = buffer_state.buffer.read(cx);
2441        let diff_change_range = range.to_offset(buffer);
2442
2443        let new_diff = diff.snapshot(cx);
2444        let mut snapshot = self.snapshot.get_mut();
2445        let base_text_changed = snapshot
2446            .diffs
2447            .get(&buffer_id)
2448            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2449
2450        snapshot.diffs.insert(buffer_id, new_diff);
2451
2452        let mut excerpt_edits = Vec::new();
2453        for locator in &buffer_state.excerpts {
2454            let mut cursor = snapshot
2455                .excerpts
2456                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2457            cursor.seek_forward(&Some(locator), Bias::Left);
2458            if let Some(excerpt) = cursor.item()
2459                && excerpt.locator == *locator
2460            {
2461                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2462                if diff_change_range.end < excerpt_buffer_range.start
2463                    || diff_change_range.start > excerpt_buffer_range.end
2464                {
2465                    continue;
2466                }
2467                let excerpt_start = cursor.start().1;
2468                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2469                let diff_change_start_in_excerpt = ExcerptOffset::new(
2470                    diff_change_range
2471                        .start
2472                        .saturating_sub(excerpt_buffer_range.start),
2473                );
2474                let diff_change_end_in_excerpt = ExcerptOffset::new(
2475                    diff_change_range
2476                        .end
2477                        .saturating_sub(excerpt_buffer_range.start),
2478                );
2479                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2480                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2481                excerpt_edits.push(Edit {
2482                    old: edit_start..edit_end,
2483                    new: edit_start..edit_end,
2484                });
2485            }
2486        }
2487
2488        let edits = Self::sync_diff_transforms(
2489            &mut snapshot,
2490            excerpt_edits,
2491            DiffChangeKind::DiffUpdated {
2492                base_changed: base_text_changed,
2493            },
2494        );
2495        if !edits.is_empty() {
2496            self.subscriptions.publish(edits);
2497        }
2498        cx.emit(Event::Edited {
2499            edited_buffer: None,
2500        });
2501    }
2502
2503    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2504        self.buffers
2505            .values()
2506            .map(|state| state.buffer.clone())
2507            .collect()
2508    }
2509
2510    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2511        self.buffers.keys().copied().collect()
2512    }
2513
2514    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2515        self.buffers
2516            .get(&buffer_id)
2517            .map(|state| state.buffer.clone())
2518    }
2519
2520    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2521        self.point_to_buffer_offset(point, cx)
2522            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2523    }
2524
2525    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2526        let buffer_id = self
2527            .snapshot
2528            .borrow()
2529            .excerpts
2530            .first()
2531            .map(|excerpt| excerpt.buffer.remote_id());
2532        buffer_id
2533            .and_then(|buffer_id| self.buffer(buffer_id))
2534            .map(|buffer| {
2535                let buffer = buffer.read(cx);
2536                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2537            })
2538            .unwrap_or_else(move || self.language_settings_at(0, cx))
2539    }
2540
2541    pub fn language_settings_at<'a, T: ToOffset>(
2542        &'a self,
2543        point: T,
2544        cx: &'a App,
2545    ) -> Cow<'a, LanguageSettings> {
2546        let mut language = None;
2547        let mut file = None;
2548        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2549            let buffer = buffer.read(cx);
2550            language = buffer.language_at(offset);
2551            file = buffer.file();
2552        }
2553        language_settings(language.map(|l| l.name()), file, cx)
2554    }
2555
2556    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2557        self.buffers.values().for_each(|state| f(&state.buffer))
2558    }
2559
2560    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2561        if let Some(title) = self.title.as_ref() {
2562            return title.into();
2563        }
2564
2565        if let Some(buffer) = self.as_singleton() {
2566            let buffer = buffer.read(cx);
2567
2568            if let Some(file) = buffer.file() {
2569                return file.file_name(cx).into();
2570            }
2571
2572            if let Some(title) = self.buffer_content_title(buffer) {
2573                return title;
2574            }
2575        };
2576
2577        "untitled".into()
2578    }
2579
2580    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2581        let mut is_leading_whitespace = true;
2582        let mut count = 0;
2583        let mut prev_was_space = false;
2584        let mut title = String::new();
2585
2586        for ch in buffer.snapshot().chars() {
2587            if is_leading_whitespace && ch.is_whitespace() {
2588                continue;
2589            }
2590
2591            is_leading_whitespace = false;
2592
2593            if ch == '\n' || count >= 40 {
2594                break;
2595            }
2596
2597            if ch.is_whitespace() {
2598                if !prev_was_space {
2599                    title.push(' ');
2600                    count += 1;
2601                    prev_was_space = true;
2602                }
2603            } else {
2604                title.push(ch);
2605                count += 1;
2606                prev_was_space = false;
2607            }
2608        }
2609
2610        let title = title.trim_end().to_string();
2611
2612        if title.is_empty() {
2613            return None;
2614        }
2615
2616        Some(title.into())
2617    }
2618
2619    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2620        self.title = Some(title);
2621        cx.notify();
2622    }
2623
2624    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2625    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2626        for buffer_state in self.buffers.values() {
2627            buffer_state
2628                .buffer
2629                .update(cx, |buffer, _cx| buffer.refresh_preview());
2630        }
2631    }
2632
2633    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2634    pub fn preserve_preview(&self, cx: &App) -> bool {
2635        self.buffers
2636            .values()
2637            .all(|state| state.buffer.read(cx).preserve_preview())
2638    }
2639
2640    #[cfg(any(test, feature = "test-support"))]
2641    pub fn is_parsing(&self, cx: &App) -> bool {
2642        self.as_singleton().unwrap().read(cx).is_parsing()
2643    }
2644
2645    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2646        let buffer_id = diff.read(cx).buffer_id;
2647        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2648        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2649    }
2650
2651    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2652        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2653    }
2654
2655    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2656        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2657    }
2658
2659    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2660        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2661    }
2662
2663    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2664        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2665        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2666    }
2667
2668    pub fn all_diff_hunks_expanded(&self) -> bool {
2669        self.snapshot.borrow().all_diff_hunks_expanded
2670    }
2671
2672    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2673        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2674        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2675    }
2676
2677    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2678        self.read(cx)
2679            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2680            .nth(1)
2681            .is_some()
2682    }
2683
2684    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2685        let snapshot = self.read(cx);
2686        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2687        let offset_range = range.to_offset(&snapshot);
2688        cursor.seek(&offset_range.start, Bias::Left);
2689        while let Some(item) = cursor.item() {
2690            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2691                break;
2692            }
2693            if item.hunk_info().is_some() {
2694                return true;
2695            }
2696            cursor.next();
2697        }
2698        false
2699    }
2700
2701    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2702        let snapshot = self.read(cx);
2703        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2704        for range in ranges {
2705            let range = range.to_point(&snapshot);
2706            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2707            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2708            let start = start.saturating_sub(1);
2709            let end = snapshot.len().min(end + 1);
2710            cursor.seek(&start, Bias::Right);
2711            while let Some(item) = cursor.item() {
2712                if *cursor.start() >= end {
2713                    break;
2714                }
2715                if item.hunk_info().is_some() {
2716                    return true;
2717                }
2718                cursor.next();
2719            }
2720        }
2721        false
2722    }
2723
2724    pub fn expand_or_collapse_diff_hunks_inner(
2725        &mut self,
2726        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2727        expand: bool,
2728        cx: &mut Context<Self>,
2729    ) {
2730        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2731            return;
2732        }
2733        self.sync(cx);
2734        let mut snapshot = self.snapshot.get_mut();
2735        let mut excerpt_edits = Vec::new();
2736        let mut last_hunk_row = None;
2737        for (range, end_excerpt_id) in ranges {
2738            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2739                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2740                    continue;
2741                }
2742                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2743                    continue;
2744                }
2745                let start = Anchor::in_buffer(
2746                    diff_hunk.excerpt_id,
2747                    diff_hunk.buffer_id,
2748                    diff_hunk.buffer_range.start,
2749                );
2750                let end = Anchor::in_buffer(
2751                    diff_hunk.excerpt_id,
2752                    diff_hunk.buffer_id,
2753                    diff_hunk.buffer_range.end,
2754                );
2755                let start = snapshot.excerpt_offset_for_anchor(&start);
2756                let end = snapshot.excerpt_offset_for_anchor(&end);
2757                last_hunk_row = Some(diff_hunk.row_range.start);
2758                excerpt_edits.push(text::Edit {
2759                    old: start..end,
2760                    new: start..end,
2761                });
2762            }
2763        }
2764
2765        let edits = Self::sync_diff_transforms(
2766            &mut snapshot,
2767            excerpt_edits,
2768            DiffChangeKind::ExpandOrCollapseHunks { expand },
2769        );
2770        if !edits.is_empty() {
2771            self.subscriptions.publish(edits);
2772        }
2773        cx.emit(Event::DiffHunksToggled);
2774        cx.emit(Event::Edited {
2775            edited_buffer: None,
2776        });
2777    }
2778
2779    pub fn expand_or_collapse_diff_hunks(
2780        &mut self,
2781        ranges: Vec<Range<Anchor>>,
2782        expand: bool,
2783        cx: &mut Context<Self>,
2784    ) {
2785        let snapshot = self.snapshot.borrow().clone();
2786        let ranges = ranges.iter().map(move |range| {
2787            let end_excerpt_id = range.end.excerpt_id;
2788            let range = range.to_point(&snapshot);
2789            let mut peek_end = range.end;
2790            if range.end.row < snapshot.max_row().0 {
2791                peek_end = Point::new(range.end.row + 1, 0);
2792            };
2793            (range.start..peek_end, end_excerpt_id)
2794        });
2795        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2796    }
2797
2798    pub fn resize_excerpt(
2799        &mut self,
2800        id: ExcerptId,
2801        range: Range<text::Anchor>,
2802        cx: &mut Context<Self>,
2803    ) {
2804        self.sync(cx);
2805
2806        let mut snapshot = self.snapshot.get_mut();
2807        let locator = snapshot.excerpt_locator_for_id(id);
2808        let mut new_excerpts = SumTree::default();
2809        let mut cursor = snapshot
2810            .excerpts
2811            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2812        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2813
2814        let prefix = cursor.slice(&Some(locator), Bias::Left);
2815        new_excerpts.append(prefix, ());
2816
2817        let mut excerpt = cursor.item().unwrap().clone();
2818        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2819
2820        excerpt.range.context.start = range.start;
2821        excerpt.range.context.end = range.end;
2822        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2823
2824        excerpt.text_summary = excerpt
2825            .buffer
2826            .text_summary_for_range(excerpt.range.context.clone());
2827
2828        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2829        let old_start_offset = cursor.start().1;
2830        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2831        let edit = Edit {
2832            old: old_start_offset..old_start_offset + old_text_len,
2833            new: new_start_offset..new_start_offset + new_text_len,
2834        };
2835
2836        if let Some(last_edit) = edits.last_mut() {
2837            if last_edit.old.end == edit.old.start {
2838                last_edit.old.end = edit.old.end;
2839                last_edit.new.end = edit.new.end;
2840            } else {
2841                edits.push(edit);
2842            }
2843        } else {
2844            edits.push(edit);
2845        }
2846
2847        new_excerpts.push(excerpt, ());
2848
2849        cursor.next();
2850
2851        new_excerpts.append(cursor.suffix(), ());
2852
2853        drop(cursor);
2854        snapshot.excerpts = new_excerpts;
2855
2856        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2857        if !edits.is_empty() {
2858            self.subscriptions.publish(edits);
2859        }
2860        cx.emit(Event::Edited {
2861            edited_buffer: None,
2862        });
2863        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2864        cx.notify();
2865    }
2866
2867    pub fn expand_excerpts(
2868        &mut self,
2869        ids: impl IntoIterator<Item = ExcerptId>,
2870        line_count: u32,
2871        direction: ExpandExcerptDirection,
2872        cx: &mut Context<Self>,
2873    ) {
2874        if line_count == 0 {
2875            return;
2876        }
2877        self.sync(cx);
2878        if !self.excerpts_by_path.is_empty() {
2879            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2880            return;
2881        }
2882        let mut snapshot = self.snapshot.get_mut();
2883
2884        let ids = ids.into_iter().collect::<Vec<_>>();
2885        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2886        let mut new_excerpts = SumTree::default();
2887        let mut cursor = snapshot
2888            .excerpts
2889            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2890        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2891
2892        for locator in &locators {
2893            let prefix = cursor.slice(&Some(locator), Bias::Left);
2894            new_excerpts.append(prefix, ());
2895
2896            let mut excerpt = cursor.item().unwrap().clone();
2897            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2898
2899            let up_line_count = if direction.should_expand_up() {
2900                line_count
2901            } else {
2902                0
2903            };
2904
2905            let start_row = excerpt
2906                .range
2907                .context
2908                .start
2909                .to_point(&excerpt.buffer)
2910                .row
2911                .saturating_sub(up_line_count);
2912            let start_point = Point::new(start_row, 0);
2913            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2914
2915            let down_line_count = if direction.should_expand_down() {
2916                line_count
2917            } else {
2918                0
2919            };
2920
2921            let mut end_point = excerpt.buffer.clip_point(
2922                excerpt.range.context.end.to_point(&excerpt.buffer)
2923                    + Point::new(down_line_count, 0),
2924                Bias::Left,
2925            );
2926            end_point.column = excerpt.buffer.line_len(end_point.row);
2927            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2928            excerpt.max_buffer_row = end_point.row;
2929
2930            excerpt.text_summary = excerpt
2931                .buffer
2932                .text_summary_for_range(excerpt.range.context.clone());
2933
2934            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2935            let old_start_offset = cursor.start().1;
2936            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2937            let edit = Edit {
2938                old: old_start_offset..old_start_offset + old_text_len,
2939                new: new_start_offset..new_start_offset + new_text_len,
2940            };
2941
2942            if let Some(last_edit) = edits.last_mut() {
2943                if last_edit.old.end == edit.old.start {
2944                    last_edit.old.end = edit.old.end;
2945                    last_edit.new.end = edit.new.end;
2946                } else {
2947                    edits.push(edit);
2948                }
2949            } else {
2950                edits.push(edit);
2951            }
2952
2953            new_excerpts.push(excerpt, ());
2954
2955            cursor.next();
2956        }
2957
2958        new_excerpts.append(cursor.suffix(), ());
2959
2960        drop(cursor);
2961        snapshot.excerpts = new_excerpts;
2962
2963        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2964        if !edits.is_empty() {
2965            self.subscriptions.publish(edits);
2966        }
2967        cx.emit(Event::Edited {
2968            edited_buffer: None,
2969        });
2970        cx.emit(Event::ExcerptsExpanded { ids });
2971        cx.notify();
2972    }
2973
2974    fn sync(&self, cx: &App) {
2975        let changed = self.buffer_changed_since_sync.replace(false);
2976        if !changed {
2977            return;
2978        }
2979
2980        let mut snapshot = self.snapshot.borrow_mut();
2981        let mut excerpts_to_edit = Vec::new();
2982        let mut non_text_state_updated = false;
2983        let mut is_dirty = false;
2984        let mut has_deleted_file = false;
2985        let mut has_conflict = false;
2986        let mut edited = false;
2987        for buffer_state in self.buffers.values() {
2988            let buffer = buffer_state.buffer.read(cx);
2989            let version = buffer.version();
2990            let non_text_state_update_count = buffer.non_text_state_update_count();
2991
2992            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2993            let buffer_non_text_state_updated =
2994                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2995            if buffer_edited || buffer_non_text_state_updated {
2996                *buffer_state.last_version.borrow_mut() = version;
2997                buffer_state
2998                    .last_non_text_state_update_count
2999                    .set(non_text_state_update_count);
3000                excerpts_to_edit.extend(
3001                    buffer_state
3002                        .excerpts
3003                        .iter()
3004                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3005                );
3006            }
3007
3008            edited |= buffer_edited;
3009            non_text_state_updated |= buffer_non_text_state_updated;
3010            is_dirty |= buffer.is_dirty();
3011            has_deleted_file |= buffer
3012                .file()
3013                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3014            has_conflict |= buffer.has_conflict();
3015        }
3016        if edited {
3017            snapshot.edit_count += 1;
3018        }
3019        if non_text_state_updated {
3020            snapshot.non_text_state_update_count += 1;
3021        }
3022        snapshot.is_dirty = is_dirty;
3023        snapshot.has_deleted_file = has_deleted_file;
3024        snapshot.has_conflict = has_conflict;
3025
3026        for (id, diff) in self.diffs.iter() {
3027            if snapshot.diffs.get(id).is_none() {
3028                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3029            }
3030        }
3031
3032        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3033
3034        let mut edits = Vec::new();
3035        let mut new_excerpts = SumTree::default();
3036        let mut cursor = snapshot
3037            .excerpts
3038            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3039
3040        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3041            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3042            let old_excerpt = cursor.item().unwrap();
3043            let buffer = buffer.read(cx);
3044            let buffer_id = buffer.remote_id();
3045
3046            let mut new_excerpt;
3047            if buffer_edited {
3048                edits.extend(
3049                    buffer
3050                        .edits_since_in_range::<usize>(
3051                            old_excerpt.buffer.version(),
3052                            old_excerpt.range.context.clone(),
3053                        )
3054                        .map(|edit| {
3055                            let excerpt_old_start = cursor.start().1;
3056                            let excerpt_new_start =
3057                                ExcerptOffset::new(new_excerpts.summary().text.len);
3058                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3059                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3060                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3061                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3062                            Edit {
3063                                old: old_start..old_end,
3064                                new: new_start..new_end,
3065                            }
3066                        }),
3067                );
3068
3069                new_excerpt = Excerpt::new(
3070                    old_excerpt.id,
3071                    locator.clone(),
3072                    buffer_id,
3073                    buffer.snapshot(),
3074                    old_excerpt.range.clone(),
3075                    old_excerpt.has_trailing_newline,
3076                );
3077            } else {
3078                new_excerpt = old_excerpt.clone();
3079                new_excerpt.buffer = buffer.snapshot();
3080            }
3081
3082            new_excerpts.push(new_excerpt, ());
3083            cursor.next();
3084        }
3085        new_excerpts.append(cursor.suffix(), ());
3086
3087        drop(cursor);
3088        snapshot.excerpts = new_excerpts;
3089
3090        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3091        if !edits.is_empty() {
3092            self.subscriptions.publish(edits);
3093        }
3094    }
3095
3096    fn sync_diff_transforms(
3097        snapshot: &mut MultiBufferSnapshot,
3098        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3099        change_kind: DiffChangeKind,
3100    ) -> Vec<Edit<usize>> {
3101        if excerpt_edits.is_empty() {
3102            return vec![];
3103        }
3104
3105        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3106        let mut old_diff_transforms = snapshot
3107            .diff_transforms
3108            .cursor::<Dimensions<ExcerptOffset, usize>>(());
3109        let mut new_diff_transforms = SumTree::default();
3110        let mut old_expanded_hunks = HashSet::default();
3111        let mut output_edits = Vec::new();
3112        let mut output_delta = 0_isize;
3113        let mut at_transform_boundary = true;
3114        let mut end_of_current_insert = None;
3115
3116        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3117        while let Some(edit) = excerpt_edits.next() {
3118            excerpts.seek_forward(&edit.new.start, Bias::Right);
3119            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3120                excerpts.prev();
3121            }
3122
3123            // Keep any transforms that are before the edit.
3124            if at_transform_boundary {
3125                at_transform_boundary = false;
3126                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3127                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3128                if let Some(transform) = old_diff_transforms.item()
3129                    && old_diff_transforms.end().0 == edit.old.start
3130                    && old_diff_transforms.start().0 < edit.old.start
3131                {
3132                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3133                    old_diff_transforms.next();
3134                }
3135            }
3136
3137            // Compute the start of the edit in output coordinates.
3138            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3139            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3140            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3141
3142            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3143                &edit,
3144                &mut excerpts,
3145                &mut old_diff_transforms,
3146                &mut new_diff_transforms,
3147                &mut end_of_current_insert,
3148                &mut old_expanded_hunks,
3149                snapshot,
3150                change_kind,
3151            );
3152
3153            // Compute the end of the edit in output coordinates.
3154            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3155            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3156            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3157            let edit_new_end =
3158                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3159            let output_edit = Edit {
3160                old: edit_old_start..edit_old_end,
3161                new: edit_new_start..edit_new_end,
3162            };
3163
3164            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3165            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3166            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3167                output_edits.push(output_edit);
3168            }
3169
3170            // If this is the last edit that intersects the current diff transform,
3171            // then recreate the content up to the end of this transform, to prepare
3172            // for reusing additional slices of the old transforms.
3173            if excerpt_edits
3174                .peek()
3175                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3176            {
3177                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3178                    && match old_diff_transforms.item() {
3179                        Some(DiffTransform::BufferContent {
3180                            inserted_hunk_info: Some(hunk),
3181                            ..
3182                        }) => excerpts.item().is_some_and(|excerpt| {
3183                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3184                        }),
3185                        _ => true,
3186                    };
3187
3188                let mut excerpt_offset = edit.new.end;
3189                if !keep_next_old_transform {
3190                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3191                    old_diff_transforms.next();
3192                }
3193
3194                old_expanded_hunks.clear();
3195                Self::push_buffer_content_transform(
3196                    snapshot,
3197                    &mut new_diff_transforms,
3198                    excerpt_offset,
3199                    end_of_current_insert,
3200                );
3201                at_transform_boundary = true;
3202            }
3203        }
3204
3205        // Keep any transforms that are after the last edit.
3206        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3207
3208        // Ensure there's always at least one buffer content transform.
3209        if new_diff_transforms.is_empty() {
3210            new_diff_transforms.push(
3211                DiffTransform::BufferContent {
3212                    summary: Default::default(),
3213                    inserted_hunk_info: None,
3214                },
3215                (),
3216            );
3217        }
3218
3219        drop(old_diff_transforms);
3220        drop(excerpts);
3221        snapshot.diff_transforms = new_diff_transforms;
3222        snapshot.edit_count += 1;
3223
3224        #[cfg(any(test, feature = "test-support"))]
3225        snapshot.check_invariants();
3226        output_edits
3227    }
3228
3229    fn recompute_diff_transforms_for_edit(
3230        edit: &Edit<TypedOffset<Excerpt>>,
3231        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3232        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
3233        new_diff_transforms: &mut SumTree<DiffTransform>,
3234        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3235        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3236        snapshot: &MultiBufferSnapshot,
3237        change_kind: DiffChangeKind,
3238    ) -> bool {
3239        log::trace!(
3240            "recomputing diff transform for edit {:?} => {:?}",
3241            edit.old.start.value..edit.old.end.value,
3242            edit.new.start.value..edit.new.end.value
3243        );
3244
3245        // Record which hunks were previously expanded.
3246        while let Some(item) = old_diff_transforms.item() {
3247            if let Some(hunk_info) = item.hunk_info() {
3248                log::trace!(
3249                    "previously expanded hunk at {}",
3250                    old_diff_transforms.start().0
3251                );
3252                old_expanded_hunks.insert(hunk_info);
3253            }
3254            if old_diff_transforms.end().0 > edit.old.end {
3255                break;
3256            }
3257            old_diff_transforms.next();
3258        }
3259
3260        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3261        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3262        if old_expanded_hunks.is_empty()
3263            && change_kind == DiffChangeKind::BufferEdited
3264            && !all_diff_hunks_expanded
3265        {
3266            return false;
3267        }
3268
3269        // Visit each excerpt that intersects the edit.
3270        let mut did_expand_hunks = false;
3271        while let Some(excerpt) = excerpts.item() {
3272            // Recompute the expanded hunks in the portion of the excerpt that
3273            // intersects the edit.
3274            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3275                let buffer = &excerpt.buffer;
3276                let excerpt_start = *excerpts.start();
3277                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3278                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3279                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3280                let edit_buffer_start =
3281                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3282                let edit_buffer_end =
3283                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3284                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3285                let edit_anchor_range =
3286                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3287
3288                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3289                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3290                        continue;
3291                    }
3292
3293                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3294                    if hunk_buffer_range.start < excerpt_buffer_start {
3295                        log::trace!("skipping hunk that starts before excerpt");
3296                        continue;
3297                    }
3298
3299                    let hunk_info = DiffTransformHunkInfo {
3300                        excerpt_id: excerpt.id,
3301                        hunk_start_anchor: hunk.buffer_range.start,
3302                        hunk_secondary_status: hunk.secondary_status,
3303                    };
3304
3305                    let hunk_excerpt_start = excerpt_start
3306                        + ExcerptOffset::new(
3307                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3308                        );
3309                    let hunk_excerpt_end = excerpt_end.min(
3310                        excerpt_start
3311                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3312                    );
3313
3314                    Self::push_buffer_content_transform(
3315                        snapshot,
3316                        new_diff_transforms,
3317                        hunk_excerpt_start,
3318                        *end_of_current_insert,
3319                    );
3320
3321                    // For every existing hunk, determine if it was previously expanded
3322                    // and if it should currently be expanded.
3323                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3324                    let should_expand_hunk = match &change_kind {
3325                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3326                            was_previously_expanded || all_diff_hunks_expanded
3327                        }
3328                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3329                            let intersects = hunk_buffer_range.is_empty()
3330                                || hunk_buffer_range.end > edit_buffer_start;
3331                            if *expand {
3332                                intersects || was_previously_expanded || all_diff_hunks_expanded
3333                            } else {
3334                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3335                            }
3336                        }
3337                        _ => was_previously_expanded || all_diff_hunks_expanded,
3338                    };
3339
3340                    if should_expand_hunk {
3341                        did_expand_hunks = true;
3342                        log::trace!(
3343                            "expanding hunk {:?}, excerpt:{:?}",
3344                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3345                            excerpt.id
3346                        );
3347
3348                        if !hunk.diff_base_byte_range.is_empty()
3349                            && hunk_buffer_range.start >= edit_buffer_start
3350                            && hunk_buffer_range.start <= excerpt_buffer_end
3351                        {
3352                            let base_text = diff.base_text();
3353                            let mut text_cursor =
3354                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3355                            let mut base_text_summary =
3356                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3357
3358                            let mut has_trailing_newline = false;
3359                            if base_text_summary.last_line_chars > 0 {
3360                                base_text_summary += TextSummary::newline();
3361                                has_trailing_newline = true;
3362                            }
3363
3364                            new_diff_transforms.push(
3365                                DiffTransform::DeletedHunk {
3366                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3367                                    summary: base_text_summary,
3368                                    buffer_id: excerpt.buffer_id,
3369                                    hunk_info,
3370                                    has_trailing_newline,
3371                                },
3372                                (),
3373                            );
3374                        }
3375
3376                        if !hunk_buffer_range.is_empty() {
3377                            *end_of_current_insert =
3378                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3379                        }
3380                    }
3381                }
3382            }
3383
3384            if excerpts.end() <= edit.new.end {
3385                excerpts.next();
3386            } else {
3387                break;
3388            }
3389        }
3390
3391        did_expand_hunks || !old_expanded_hunks.is_empty()
3392    }
3393
3394    fn append_diff_transforms(
3395        new_transforms: &mut SumTree<DiffTransform>,
3396        subtree: SumTree<DiffTransform>,
3397    ) {
3398        if let Some(DiffTransform::BufferContent {
3399            inserted_hunk_info,
3400            summary,
3401        }) = subtree.first()
3402            && Self::extend_last_buffer_content_transform(
3403                new_transforms,
3404                *inserted_hunk_info,
3405                *summary,
3406            )
3407        {
3408            let mut cursor = subtree.cursor::<()>(());
3409            cursor.next();
3410            cursor.next();
3411            new_transforms.append(cursor.suffix(), ());
3412            return;
3413        }
3414        new_transforms.append(subtree, ());
3415    }
3416
3417    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3418        if let DiffTransform::BufferContent {
3419            inserted_hunk_info: inserted_hunk_anchor,
3420            summary,
3421        } = transform
3422            && Self::extend_last_buffer_content_transform(
3423                new_transforms,
3424                inserted_hunk_anchor,
3425                summary,
3426            )
3427        {
3428            return;
3429        }
3430        new_transforms.push(transform, ());
3431    }
3432
3433    fn push_buffer_content_transform(
3434        old_snapshot: &MultiBufferSnapshot,
3435        new_transforms: &mut SumTree<DiffTransform>,
3436        end_offset: ExcerptOffset,
3437        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3438    ) {
3439        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3440            (end_offset.min(insertion_end_offset), Some(hunk_info))
3441        });
3442        let unchanged_region = [(end_offset, None)];
3443
3444        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3445        {
3446            let start_offset = new_transforms.summary().excerpt_len();
3447            if end_offset <= start_offset {
3448                continue;
3449            }
3450            let summary_to_add = old_snapshot
3451                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3452
3453            if !Self::extend_last_buffer_content_transform(
3454                new_transforms,
3455                inserted_hunk_info,
3456                summary_to_add,
3457            ) {
3458                new_transforms.push(
3459                    DiffTransform::BufferContent {
3460                        summary: summary_to_add,
3461                        inserted_hunk_info,
3462                    },
3463                    (),
3464                )
3465            }
3466        }
3467    }
3468
3469    fn extend_last_buffer_content_transform(
3470        new_transforms: &mut SumTree<DiffTransform>,
3471        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3472        summary_to_add: TextSummary,
3473    ) -> bool {
3474        let mut did_extend = false;
3475        new_transforms.update_last(
3476            |last_transform| {
3477                if let DiffTransform::BufferContent {
3478                    summary,
3479                    inserted_hunk_info: inserted_hunk_anchor,
3480                } = last_transform
3481                    && *inserted_hunk_anchor == new_inserted_hunk_info
3482                {
3483                    *summary += summary_to_add;
3484                    did_extend = true;
3485                }
3486            },
3487            (),
3488        );
3489        did_extend
3490    }
3491}
3492
3493fn build_excerpt_ranges(
3494    ranges: impl IntoIterator<Item = Range<Point>>,
3495    context_line_count: u32,
3496    buffer_snapshot: &BufferSnapshot,
3497) -> Vec<ExcerptRange<Point>> {
3498    ranges
3499        .into_iter()
3500        .map(|range| {
3501            let start_row = range.start.row.saturating_sub(context_line_count);
3502            let start = Point::new(start_row, 0);
3503            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3504            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3505            ExcerptRange {
3506                context: start..end,
3507                primary: range,
3508            }
3509        })
3510        .collect()
3511}
3512
3513#[cfg(any(test, feature = "test-support"))]
3514impl MultiBuffer {
3515    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3516        let buffer = cx.new(|cx| Buffer::local(text, cx));
3517        cx.new(|cx| Self::singleton(buffer, cx))
3518    }
3519
3520    pub fn build_multi<const COUNT: usize>(
3521        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3522        cx: &mut gpui::App,
3523    ) -> Entity<Self> {
3524        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3525        for (text, ranges) in excerpts {
3526            let buffer = cx.new(|cx| Buffer::local(text, cx));
3527            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3528            multi.update(cx, |multi, cx| {
3529                multi.push_excerpts(buffer, excerpt_ranges, cx)
3530            });
3531        }
3532
3533        multi
3534    }
3535
3536    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3537        cx.new(|cx| Self::singleton(buffer, cx))
3538    }
3539
3540    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3541        cx.new(|cx| {
3542            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3543            let mutation_count = rng.random_range(1..=5);
3544            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3545            multibuffer
3546        })
3547    }
3548
3549    pub fn randomly_edit(
3550        &mut self,
3551        rng: &mut impl rand::Rng,
3552        edit_count: usize,
3553        cx: &mut Context<Self>,
3554    ) {
3555        use util::RandomCharIter;
3556
3557        let snapshot = self.read(cx);
3558        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3559        let mut last_end = None;
3560        for _ in 0..edit_count {
3561            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3562                break;
3563            }
3564
3565            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3566            let end =
3567                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3568            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3569            last_end = Some(end);
3570
3571            let mut range = start..end;
3572            if rng.random_bool(0.2) {
3573                mem::swap(&mut range.start, &mut range.end);
3574            }
3575
3576            let new_text_len = rng.random_range(0..10);
3577            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3578
3579            edits.push((range, new_text.into()));
3580        }
3581        log::info!("mutating multi-buffer with {:?}", edits);
3582        drop(snapshot);
3583
3584        self.edit(edits, None, cx);
3585    }
3586
3587    pub fn randomly_edit_excerpts(
3588        &mut self,
3589        rng: &mut impl rand::Rng,
3590        mutation_count: usize,
3591        cx: &mut Context<Self>,
3592    ) {
3593        use rand::prelude::*;
3594        use std::env;
3595        use util::RandomCharIter;
3596
3597        let max_excerpts = env::var("MAX_EXCERPTS")
3598            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3599            .unwrap_or(5);
3600
3601        let mut buffers = Vec::new();
3602        for _ in 0..mutation_count {
3603            if rng.random_bool(0.05) {
3604                log::info!("Clearing multi-buffer");
3605                self.clear(cx);
3606                continue;
3607            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3608                let ids = self.excerpt_ids();
3609                let mut excerpts = HashSet::default();
3610                for _ in 0..rng.random_range(0..ids.len()) {
3611                    excerpts.extend(ids.choose(rng).copied());
3612                }
3613
3614                let line_count = rng.random_range(0..5);
3615
3616                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3617
3618                self.expand_excerpts(
3619                    excerpts.iter().cloned(),
3620                    line_count,
3621                    ExpandExcerptDirection::UpAndDown,
3622                    cx,
3623                );
3624                continue;
3625            }
3626
3627            let excerpt_ids = self.excerpt_ids();
3628            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3629                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3630                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3631                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3632                    let buffer = buffers.last().unwrap().read(cx);
3633                    log::info!(
3634                        "Creating new buffer {} with text: {:?}",
3635                        buffer.remote_id(),
3636                        buffer.text()
3637                    );
3638                    buffers.last().unwrap().clone()
3639                } else {
3640                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3641                };
3642
3643                let buffer = buffer_handle.read(cx);
3644                let buffer_text = buffer.text();
3645                let ranges = (0..rng.random_range(0..5))
3646                    .map(|_| {
3647                        let end_ix =
3648                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3649                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3650                        ExcerptRange::new(start_ix..end_ix)
3651                    })
3652                    .collect::<Vec<_>>();
3653                log::info!(
3654                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3655                    buffer_handle.read(cx).remote_id(),
3656                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3657                    ranges
3658                        .iter()
3659                        .map(|r| &buffer_text[r.context.clone()])
3660                        .collect::<Vec<_>>()
3661                );
3662
3663                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3664                log::info!("Inserted with ids: {:?}", excerpt_id);
3665            } else {
3666                let remove_count = rng.random_range(1..=excerpt_ids.len());
3667                let mut excerpts_to_remove = excerpt_ids
3668                    .choose_multiple(rng, remove_count)
3669                    .cloned()
3670                    .collect::<Vec<_>>();
3671                let snapshot = self.snapshot.borrow();
3672                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3673                drop(snapshot);
3674                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3675                self.remove_excerpts(excerpts_to_remove, cx);
3676            }
3677        }
3678    }
3679
3680    pub fn randomly_mutate(
3681        &mut self,
3682        rng: &mut impl rand::Rng,
3683        mutation_count: usize,
3684        cx: &mut Context<Self>,
3685    ) {
3686        use rand::prelude::*;
3687
3688        if rng.random_bool(0.7) || self.singleton {
3689            let buffer = self
3690                .buffers
3691                .values()
3692                .choose(rng)
3693                .map(|state| state.buffer.clone());
3694
3695            if let Some(buffer) = buffer {
3696                buffer.update(cx, |buffer, cx| {
3697                    if rng.random() {
3698                        buffer.randomly_edit(rng, mutation_count, cx);
3699                    } else {
3700                        buffer.randomly_undo_redo(rng, cx);
3701                    }
3702                });
3703            } else {
3704                self.randomly_edit(rng, mutation_count, cx);
3705            }
3706        } else {
3707            self.randomly_edit_excerpts(rng, mutation_count, cx);
3708        }
3709
3710        self.check_invariants(cx);
3711    }
3712
3713    fn check_invariants(&self, cx: &App) {
3714        self.read(cx).check_invariants();
3715    }
3716}
3717
3718impl EventEmitter<Event> for MultiBuffer {}
3719
3720impl MultiBufferSnapshot {
3721    pub fn text(&self) -> String {
3722        self.chunks(0..self.len(), false)
3723            .map(|chunk| chunk.text)
3724            .collect()
3725    }
3726
3727    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3728        self.reversed_chunks_in_range(0..position.to_offset(self))
3729            .flat_map(|c| c.chars().rev())
3730    }
3731
3732    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3733        let mut cursor = self.cursor::<usize>();
3734        cursor.seek(&range.end);
3735        let current_chunks = cursor.region().as_ref().map(|region| {
3736            let start_overshoot = range.start.saturating_sub(region.range.start);
3737            let end_overshoot = range.end - region.range.start;
3738            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3739            let start = region.buffer_range.start + start_overshoot;
3740            region.buffer.reversed_chunks_in_range(start..end)
3741        });
3742        ReversedMultiBufferChunks {
3743            cursor,
3744            current_chunks,
3745            start: range.start,
3746            offset: range.end,
3747        }
3748    }
3749
3750    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3751        let offset = position.to_offset(self);
3752        self.text_for_range(offset..self.len())
3753            .flat_map(|chunk| chunk.chars())
3754    }
3755
3756    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3757        self.chunks(range, false).map(|chunk| chunk.text)
3758    }
3759
3760    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3761        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3762            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3763    }
3764
3765    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3766    where
3767        T: ToOffset,
3768    {
3769        let position = position.to_offset(self);
3770        position == self.clip_offset(position, Bias::Left)
3771            && self
3772                .bytes_in_range(position..self.len())
3773                .flatten()
3774                .copied()
3775                .take(needle.len())
3776                .eq(needle.bytes())
3777    }
3778
3779    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3780        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3781    }
3782
3783    pub fn diff_hunks_in_range<T: ToPoint>(
3784        &self,
3785        range: Range<T>,
3786    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3787        let query_range = range.start.to_point(self)..range.end.to_point(self);
3788        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3789            let diff = self.diffs.get(&buffer.remote_id())?;
3790            let buffer_start = buffer.anchor_before(buffer_range.start);
3791            let buffer_end = buffer.anchor_after(buffer_range.end);
3792            Some(
3793                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3794                    .filter_map(|hunk| {
3795                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3796                            return None;
3797                        }
3798                        Some((hunk.range.clone(), hunk))
3799                    }),
3800            )
3801        })
3802        .filter_map(move |(range, hunk, excerpt)| {
3803            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3804            {
3805                return None;
3806            }
3807            let end_row = if range.end.column == 0 {
3808                range.end.row
3809            } else {
3810                range.end.row + 1
3811            };
3812            Some(MultiBufferDiffHunk {
3813                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3814                buffer_id: excerpt.buffer_id,
3815                excerpt_id: excerpt.id,
3816                buffer_range: hunk.buffer_range.clone(),
3817                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3818                secondary_status: hunk.secondary_status,
3819            })
3820        })
3821    }
3822
3823    pub fn excerpt_ids_for_range<T: ToOffset>(
3824        &self,
3825        range: Range<T>,
3826    ) -> impl Iterator<Item = ExcerptId> + '_ {
3827        let range = range.start.to_offset(self)..range.end.to_offset(self);
3828        let mut cursor = self.cursor::<usize>();
3829        cursor.seek(&range.start);
3830        std::iter::from_fn(move || {
3831            let region = cursor.region()?;
3832            if region.range.start >= range.end {
3833                return None;
3834            }
3835            cursor.next_excerpt();
3836            Some(region.excerpt.id)
3837        })
3838    }
3839
3840    pub fn buffer_ids_for_range<T: ToOffset>(
3841        &self,
3842        range: Range<T>,
3843    ) -> impl Iterator<Item = BufferId> + '_ {
3844        let range = range.start.to_offset(self)..range.end.to_offset(self);
3845        let mut cursor = self.cursor::<usize>();
3846        cursor.seek(&range.start);
3847        std::iter::from_fn(move || {
3848            let region = cursor.region()?;
3849            if region.range.start > range.end
3850                || region.range.start == range.end && region.range.start > range.start
3851            {
3852                return None;
3853            }
3854            cursor.next_excerpt();
3855            Some(region.excerpt.buffer_id)
3856        })
3857    }
3858
3859    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3860        &self,
3861        ranges: impl Iterator<Item = Range<T>>,
3862    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3863        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3864    }
3865
3866    pub fn range_to_buffer_ranges<T: ToOffset>(
3867        &self,
3868        range: Range<T>,
3869    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3870        let start = range.start.to_offset(self);
3871        let end = range.end.to_offset(self);
3872
3873        let mut cursor = self.cursor::<usize>();
3874        cursor.seek(&start);
3875
3876        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3877        while let Some(region) = cursor.region() {
3878            if region.range.start > end {
3879                break;
3880            }
3881            if region.is_main_buffer {
3882                let start_overshoot = start.saturating_sub(region.range.start);
3883                let end_overshoot = end.saturating_sub(region.range.start);
3884                let start = region
3885                    .buffer_range
3886                    .end
3887                    .min(region.buffer_range.start + start_overshoot);
3888                let end = region
3889                    .buffer_range
3890                    .end
3891                    .min(region.buffer_range.start + end_overshoot);
3892                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3893                    *excerpt_id == region.excerpt.id && prev_range.end == start
3894                }) {
3895                    prev.1.end = end;
3896                } else {
3897                    result.push((region.buffer, start..end, region.excerpt.id));
3898                }
3899            }
3900            cursor.next();
3901        }
3902        result
3903    }
3904
3905    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3906        &self,
3907        range: Range<T>,
3908    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3909        let start = range.start.to_offset(self);
3910        let end = range.end.to_offset(self);
3911
3912        let mut cursor = self.cursor::<usize>();
3913        cursor.seek(&start);
3914
3915        std::iter::from_fn(move || {
3916            let region = cursor.region()?;
3917            if region.range.start > end {
3918                return None;
3919            }
3920            let start_overshoot = start.saturating_sub(region.range.start);
3921            let end_overshoot = end.saturating_sub(region.range.start);
3922            let start = region
3923                .buffer_range
3924                .end
3925                .min(region.buffer_range.start + start_overshoot);
3926            let end = region
3927                .buffer_range
3928                .end
3929                .min(region.buffer_range.start + end_overshoot);
3930
3931            let region_excerpt_id = region.excerpt.id;
3932            let deleted_hunk_anchor = if region.is_main_buffer {
3933                None
3934            } else {
3935                Some(self.anchor_before(region.range.start))
3936            };
3937            let result = (
3938                region.buffer,
3939                start..end,
3940                region_excerpt_id,
3941                deleted_hunk_anchor,
3942            );
3943            cursor.next();
3944            Some(result)
3945        })
3946    }
3947
3948    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3949    /// coordinates.
3950    ///
3951    /// The given callback will be called for every excerpt intersecting the given range. It will
3952    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3953    /// The callback should return an iterator of metadata items from that buffer, each paired
3954    /// with a buffer range.
3955    ///
3956    /// The returned iterator yields each of these metadata items, paired with its range in
3957    /// multi-buffer coordinates.
3958    fn lift_buffer_metadata<'a, D, M, I>(
3959        &'a self,
3960        query_range: Range<D>,
3961        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3962    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3963    where
3964        I: Iterator<Item = (Range<D>, M)> + 'a,
3965        D: TextDimension + Ord + Sub<D, Output = D>,
3966    {
3967        let max_position = D::from_text_summary(&self.text_summary());
3968        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3969        let mut cursor = self.cursor::<D>();
3970
3971        // Find the excerpt and buffer offset where the given range ends.
3972        cursor.seek(&query_range.end);
3973        let mut range_end = None;
3974        while let Some(region) = cursor.region() {
3975            if region.is_main_buffer {
3976                let mut buffer_end = region.buffer_range.start;
3977                let overshoot = if query_range.end > region.range.start {
3978                    query_range.end - region.range.start
3979                } else {
3980                    D::default()
3981                };
3982                buffer_end.add_assign(&overshoot);
3983                range_end = Some((region.excerpt.id, buffer_end));
3984                break;
3985            }
3986            cursor.next();
3987        }
3988
3989        cursor.seek(&query_range.start);
3990
3991        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3992            && region.range.start > D::zero(())
3993        {
3994            cursor.prev()
3995        }
3996
3997        iter::from_fn(move || {
3998            loop {
3999                let excerpt = cursor.excerpt()?;
4000
4001                // If we have already retrieved metadata for this excerpt, continue to use it.
4002                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4003                    .as_mut()
4004                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4005                {
4006                    Some(metadata)
4007                }
4008                // Otherwise, compute the intersection of the input range with the excerpt's range,
4009                // and retrieve the metadata for the resulting range.
4010                else {
4011                    let region = cursor.region()?;
4012                    let mut buffer_start;
4013                    if region.is_main_buffer {
4014                        buffer_start = region.buffer_range.start;
4015                        if query_range.start > region.range.start {
4016                            let overshoot = query_range.start - region.range.start;
4017                            buffer_start.add_assign(&overshoot);
4018                        }
4019                        buffer_start = buffer_start.min(region.buffer_range.end);
4020                    } else {
4021                        buffer_start = cursor.main_buffer_position()?;
4022                    };
4023                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4024                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4025                        && excerpt.id == end_excerpt_id
4026                    {
4027                        buffer_end = buffer_end.min(end_buffer_offset);
4028                    }
4029
4030                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4031                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4032                    })
4033                };
4034
4035                // Visit each metadata item.
4036                if let Some((metadata_buffer_range, metadata)) =
4037                    metadata_iter.and_then(Iterator::next)
4038                {
4039                    // Find the multibuffer regions that contain the start and end of
4040                    // the metadata item's range.
4041                    if metadata_buffer_range.start > D::default() {
4042                        while let Some(region) = cursor.region() {
4043                            if region.is_main_buffer
4044                                && (region.buffer_range.end >= metadata_buffer_range.start
4045                                    || cursor.is_at_end_of_excerpt())
4046                            {
4047                                break;
4048                            }
4049                            cursor.next();
4050                        }
4051                    }
4052                    let start_region = cursor.region()?;
4053                    while let Some(region) = cursor.region() {
4054                        if region.is_main_buffer
4055                            && (region.buffer_range.end > metadata_buffer_range.end
4056                                || cursor.is_at_end_of_excerpt())
4057                        {
4058                            break;
4059                        }
4060                        cursor.next();
4061                    }
4062                    let end_region = cursor.region();
4063
4064                    // Convert the metadata item's range into multibuffer coordinates.
4065                    let mut start_position = start_region.range.start;
4066                    let region_buffer_start = start_region.buffer_range.start;
4067                    if start_region.is_main_buffer
4068                        && metadata_buffer_range.start > region_buffer_start
4069                    {
4070                        start_position
4071                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4072                        start_position = start_position.min(start_region.range.end);
4073                    }
4074
4075                    let mut end_position = max_position;
4076                    if let Some(end_region) = &end_region {
4077                        end_position = end_region.range.start;
4078                        debug_assert!(end_region.is_main_buffer);
4079                        let region_buffer_start = end_region.buffer_range.start;
4080                        if metadata_buffer_range.end > region_buffer_start {
4081                            end_position
4082                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4083                        }
4084                        end_position = end_position.min(end_region.range.end);
4085                    }
4086
4087                    if start_position <= query_range.end && end_position >= query_range.start {
4088                        return Some((start_position..end_position, metadata, excerpt));
4089                    }
4090                }
4091                // When there are no more metadata items for this excerpt, move to the next excerpt.
4092                else {
4093                    current_excerpt_metadata.take();
4094                    if let Some((end_excerpt_id, _)) = range_end
4095                        && excerpt.id == end_excerpt_id
4096                    {
4097                        return None;
4098                    }
4099                    cursor.next_excerpt();
4100                }
4101            }
4102        })
4103    }
4104
4105    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4106        let offset = position.to_offset(self);
4107
4108        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4109        cursor.seek(&DimensionPair {
4110            key: offset,
4111            value: None,
4112        });
4113        cursor.seek_to_start_of_current_excerpt();
4114        let excerpt = cursor.excerpt()?;
4115
4116        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4117        let current_position = self
4118            .anchor_before(offset)
4119            .text_anchor
4120            .to_offset(&excerpt.buffer);
4121        let excerpt_end = excerpt
4122            .buffer
4123            .anchor_before(excerpt_end.min(current_position));
4124
4125        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4126            for hunk in diff.hunks_intersecting_range_rev(
4127                excerpt.range.context.start..excerpt_end,
4128                &excerpt.buffer,
4129            ) {
4130                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4131                if hunk_end >= current_position {
4132                    continue;
4133                }
4134                let start =
4135                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4136                        .to_point(self);
4137                return Some(MultiBufferRow(start.row));
4138            }
4139        }
4140
4141        loop {
4142            cursor.prev_excerpt();
4143            let excerpt = cursor.excerpt()?;
4144
4145            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4146                continue;
4147            };
4148            let mut hunks =
4149                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4150            let Some(hunk) = hunks.next() else {
4151                continue;
4152            };
4153            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4154                .to_point(self);
4155            return Some(MultiBufferRow(start.row));
4156        }
4157    }
4158
4159    pub fn has_diff_hunks(&self) -> bool {
4160        self.diffs.values().any(|diff| !diff.is_empty())
4161    }
4162
4163    pub fn is_inside_word<T: ToOffset>(
4164        &self,
4165        position: T,
4166        scope_context: Option<CharScopeContext>,
4167    ) -> bool {
4168        let position = position.to_offset(self);
4169        let classifier = self
4170            .char_classifier_at(position)
4171            .scope_context(scope_context);
4172        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4173        let prev_char_kind = self
4174            .reversed_chars_at(position)
4175            .next()
4176            .map(|c| classifier.kind(c));
4177        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4178    }
4179
4180    pub fn surrounding_word<T: ToOffset>(
4181        &self,
4182        start: T,
4183        scope_context: Option<CharScopeContext>,
4184    ) -> (Range<usize>, Option<CharKind>) {
4185        let mut start = start.to_offset(self);
4186        let mut end = start;
4187        let mut next_chars = self.chars_at(start).peekable();
4188        let mut prev_chars = self.reversed_chars_at(start).peekable();
4189
4190        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4191
4192        let word_kind = cmp::max(
4193            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4194            next_chars.peek().copied().map(|c| classifier.kind(c)),
4195        );
4196
4197        for ch in prev_chars {
4198            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4199                start -= ch.len_utf8();
4200            } else {
4201                break;
4202            }
4203        }
4204
4205        for ch in next_chars {
4206            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4207                end += ch.len_utf8();
4208            } else {
4209                break;
4210            }
4211        }
4212
4213        (start..end, word_kind)
4214    }
4215
4216    pub fn char_kind_before<T: ToOffset>(
4217        &self,
4218        start: T,
4219        scope_context: Option<CharScopeContext>,
4220    ) -> Option<CharKind> {
4221        let start = start.to_offset(self);
4222        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4223        self.reversed_chars_at(start)
4224            .next()
4225            .map(|ch| classifier.kind(ch))
4226    }
4227
4228    pub fn is_singleton(&self) -> bool {
4229        self.singleton
4230    }
4231
4232    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4233        if self.singleton {
4234            self.excerpts
4235                .iter()
4236                .next()
4237                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4238        } else {
4239            None
4240        }
4241    }
4242
4243    pub fn len(&self) -> usize {
4244        self.diff_transforms.summary().output.len
4245    }
4246
4247    pub fn is_empty(&self) -> bool {
4248        self.excerpts.summary().text.len == 0
4249    }
4250
4251    pub fn widest_line_number(&self) -> u32 {
4252        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4253        self.excerpts.summary().widest_line_number + 1
4254    }
4255
4256    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4257        let range = range.start.to_offset(self)..range.end.to_offset(self);
4258        let mut excerpts = self.cursor::<usize>();
4259        excerpts.seek(&range.start);
4260
4261        let mut chunk;
4262        let mut has_trailing_newline;
4263        let excerpt_bytes;
4264        if let Some(region) = excerpts.region() {
4265            let mut bytes = region.buffer.bytes_in_range(
4266                region.buffer_range.start + range.start - region.range.start
4267                    ..(region.buffer_range.start + range.end - region.range.start)
4268                        .min(region.buffer_range.end),
4269            );
4270            chunk = bytes.next().unwrap_or(&[][..]);
4271            excerpt_bytes = Some(bytes);
4272            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4273            if chunk.is_empty() && has_trailing_newline {
4274                chunk = b"\n";
4275                has_trailing_newline = false;
4276            }
4277        } else {
4278            chunk = &[][..];
4279            excerpt_bytes = None;
4280            has_trailing_newline = false;
4281        };
4282
4283        MultiBufferBytes {
4284            range,
4285            cursor: excerpts,
4286            excerpt_bytes,
4287            has_trailing_newline,
4288            chunk,
4289        }
4290    }
4291
4292    pub fn reversed_bytes_in_range<T: ToOffset>(
4293        &self,
4294        range: Range<T>,
4295    ) -> ReversedMultiBufferBytes<'_> {
4296        let range = range.start.to_offset(self)..range.end.to_offset(self);
4297        let mut chunks = self.reversed_chunks_in_range(range.clone());
4298        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4299        ReversedMultiBufferBytes {
4300            range,
4301            chunks,
4302            chunk,
4303        }
4304    }
4305
4306    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4307        let mut cursor = self.cursor::<Point>();
4308        cursor.seek(&Point::new(start_row.0, 0));
4309        let mut result = MultiBufferRows {
4310            point: Point::new(0, 0),
4311            is_empty: self.excerpts.is_empty(),
4312            is_singleton: self.is_singleton(),
4313            cursor,
4314        };
4315        result.seek(start_row);
4316        result
4317    }
4318
4319    pub fn chunks<T: ToOffset>(
4320        &self,
4321        range: Range<T>,
4322        language_aware: bool,
4323    ) -> MultiBufferChunks<'_> {
4324        let mut chunks = MultiBufferChunks {
4325            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4326            range: 0..0,
4327            excerpts: self.excerpts.cursor(()),
4328            diff_transforms: self.diff_transforms.cursor(()),
4329            diffs: &self.diffs,
4330            diff_base_chunks: None,
4331            excerpt_chunks: None,
4332            buffer_chunk: None,
4333            language_aware,
4334        };
4335        let range = range.start.to_offset(self)..range.end.to_offset(self);
4336        chunks.seek(range);
4337        chunks
4338    }
4339
4340    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4341        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4342    }
4343
4344    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4345        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4346    }
4347
4348    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4349        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4350    }
4351
4352    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4353        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4354            buffer.clip_point_utf16(Unclipped(point), bias)
4355        })
4356    }
4357
4358    pub fn offset_to_point(&self, offset: usize) -> Point {
4359        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4360    }
4361
4362    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4363        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4364    }
4365
4366    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4367        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4368    }
4369
4370    pub fn point_to_offset(&self, point: Point) -> usize {
4371        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4372    }
4373
4374    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4375        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4376    }
4377
4378    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4379        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4380    }
4381
4382    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4383        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4384    }
4385
4386    fn clip_dimension<D>(
4387        &self,
4388        position: D,
4389        bias: Bias,
4390        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4391    ) -> D
4392    where
4393        D: TextDimension + Ord + Sub<D, Output = D>,
4394    {
4395        let mut cursor = self.cursor();
4396        cursor.seek(&position);
4397        if let Some(region) = cursor.region() {
4398            if position >= region.range.end {
4399                return region.range.end;
4400            }
4401            let overshoot = position - region.range.start;
4402            let mut buffer_position = region.buffer_range.start;
4403            buffer_position.add_assign(&overshoot);
4404            let clipped_buffer_position =
4405                clip_buffer_position(region.buffer, buffer_position, bias);
4406            let mut position = region.range.start;
4407            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4408            position
4409        } else {
4410            D::from_text_summary(&self.text_summary())
4411        }
4412    }
4413
4414    fn convert_dimension<D1, D2>(
4415        &self,
4416        key: D1,
4417        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4418    ) -> D2
4419    where
4420        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4421        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4422    {
4423        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4424        cursor.seek(&DimensionPair { key, value: None });
4425        if let Some(region) = cursor.region() {
4426            if key >= region.range.end.key {
4427                return region.range.end.value.unwrap();
4428            }
4429            let start_key = region.range.start.key;
4430            let start_value = region.range.start.value.unwrap();
4431            let buffer_start_key = region.buffer_range.start.key;
4432            let buffer_start_value = region.buffer_range.start.value.unwrap();
4433            let mut buffer_key = buffer_start_key;
4434            buffer_key.add_assign(&(key - start_key));
4435            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4436            let mut result = start_value;
4437            result.add_assign(&(buffer_value - buffer_start_value));
4438            result
4439        } else {
4440            D2::from_text_summary(&self.text_summary())
4441        }
4442    }
4443
4444    pub fn point_to_buffer_offset<T: ToOffset>(
4445        &self,
4446        point: T,
4447    ) -> Option<(&BufferSnapshot, usize)> {
4448        let offset = point.to_offset(self);
4449        let mut cursor = self.cursor::<usize>();
4450        cursor.seek(&offset);
4451        let region = cursor.region()?;
4452        let overshoot = offset - region.range.start;
4453        let buffer_offset = region.buffer_range.start + overshoot;
4454        if buffer_offset == region.buffer.len() + 1
4455            && region.has_trailing_newline
4456            && !region.is_main_buffer
4457        {
4458            let main_buffer_position = cursor.main_buffer_position()?;
4459            let buffer_snapshot = &cursor.excerpt()?.buffer;
4460            // remove this assert once we figure out the cause of the panics for #40453
4461            buffer_snapshot
4462                .text
4463                .as_rope()
4464                .assert_char_boundary(main_buffer_position);
4465            return Some((buffer_snapshot, main_buffer_position));
4466        } else if buffer_offset > region.buffer.len() {
4467            return None;
4468        }
4469        // remove this assert once we figure out the cause of the panics for #40453
4470        region
4471            .buffer
4472            .text
4473            .as_rope()
4474            .assert_char_boundary(buffer_offset);
4475        Some((region.buffer, buffer_offset))
4476    }
4477
4478    pub fn point_to_buffer_point(
4479        &self,
4480        point: Point,
4481    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4482        let mut cursor = self.cursor::<Point>();
4483        cursor.seek(&point);
4484        let region = cursor.region()?;
4485        let overshoot = point - region.range.start;
4486        let buffer_point = region.buffer_range.start + overshoot;
4487        let excerpt = cursor.excerpt()?;
4488        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4489            && region.has_trailing_newline
4490            && !region.is_main_buffer
4491        {
4492            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4493        } else if buffer_point > region.buffer.max_point() {
4494            return None;
4495        }
4496        Some((region.buffer, buffer_point, excerpt.id))
4497    }
4498
4499    pub fn suggested_indents(
4500        &self,
4501        rows: impl IntoIterator<Item = u32>,
4502        cx: &App,
4503    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4504        let mut result = BTreeMap::new();
4505
4506        let mut rows_for_excerpt = Vec::new();
4507        let mut cursor = self.cursor::<Point>();
4508        let mut rows = rows.into_iter().peekable();
4509        let mut prev_row = u32::MAX;
4510        let mut prev_language_indent_size = IndentSize::default();
4511
4512        while let Some(row) = rows.next() {
4513            cursor.seek(&Point::new(row, 0));
4514            let Some(region) = cursor.region() else {
4515                continue;
4516            };
4517
4518            // Retrieve the language and indent size once for each disjoint region being indented.
4519            let single_indent_size = if row.saturating_sub(1) == prev_row {
4520                prev_language_indent_size
4521            } else {
4522                region
4523                    .buffer
4524                    .language_indent_size_at(Point::new(row, 0), cx)
4525            };
4526            prev_language_indent_size = single_indent_size;
4527            prev_row = row;
4528
4529            let start_buffer_row = region.buffer_range.start.row;
4530            let start_multibuffer_row = region.range.start.row;
4531            let end_multibuffer_row = region.range.end.row;
4532
4533            rows_for_excerpt.push(row);
4534            while let Some(next_row) = rows.peek().copied() {
4535                if end_multibuffer_row > next_row {
4536                    rows_for_excerpt.push(next_row);
4537                    rows.next();
4538                } else {
4539                    break;
4540                }
4541            }
4542
4543            let buffer_rows = rows_for_excerpt
4544                .drain(..)
4545                .map(|row| start_buffer_row + row - start_multibuffer_row);
4546            let buffer_indents = region
4547                .buffer
4548                .suggested_indents(buffer_rows, single_indent_size);
4549            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4550                (
4551                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4552                    indent,
4553                )
4554            });
4555            result.extend(multibuffer_indents);
4556        }
4557
4558        result
4559    }
4560
4561    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4562        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4563            let mut size = buffer.indent_size_for_line(range.start.row);
4564            size.len = size
4565                .len
4566                .min(range.end.column)
4567                .saturating_sub(range.start.column);
4568            size
4569        } else {
4570            IndentSize::spaces(0)
4571        }
4572    }
4573
4574    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4575        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4576            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4577        } else {
4578            LineIndent::spaces(0)
4579        }
4580    }
4581
4582    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4583        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4584
4585        if self.language_settings(cx).extend_comment_on_newline
4586            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4587        {
4588            let delimiters = language_scope.line_comment_prefixes();
4589            for delimiter in delimiters {
4590                if *self
4591                    .chars_at(Point::new(row.0, indent.len() as u32))
4592                    .take(delimiter.chars().count())
4593                    .collect::<String>()
4594                    .as_str()
4595                    == **delimiter
4596                {
4597                    indent.push_str(delimiter);
4598                    break;
4599                }
4600            }
4601        }
4602
4603        indent
4604    }
4605
4606    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4607    where
4608        T: ToOffset,
4609    {
4610        for char in self.reversed_chars_at(position) {
4611            if !char.is_whitespace() {
4612                return false;
4613            }
4614            if char == '\n' {
4615                return true;
4616            }
4617        }
4618        true
4619    }
4620
4621    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4622        while row.0 > 0 {
4623            row.0 -= 1;
4624            if !self.is_line_blank(row) {
4625                return Some(row);
4626            }
4627        }
4628        None
4629    }
4630
4631    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4632        if let Some((_, range)) = self.buffer_line_for_row(row) {
4633            range.end.column - range.start.column
4634        } else {
4635            0
4636        }
4637    }
4638
4639    pub fn buffer_line_for_row(
4640        &self,
4641        row: MultiBufferRow,
4642    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4643        let mut cursor = self.cursor::<Point>();
4644        let point = Point::new(row.0, 0);
4645        cursor.seek(&point);
4646        let region = cursor.region()?;
4647        let overshoot = point.min(region.range.end) - region.range.start;
4648        let buffer_point = region.buffer_range.start + overshoot;
4649        if buffer_point.row > region.buffer_range.end.row {
4650            return None;
4651        }
4652        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4653        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4654            .min(region.buffer_range.end);
4655        Some((region.buffer, line_start..line_end))
4656    }
4657
4658    pub fn max_point(&self) -> Point {
4659        self.text_summary().lines
4660    }
4661
4662    pub fn max_row(&self) -> MultiBufferRow {
4663        MultiBufferRow(self.text_summary().lines.row)
4664    }
4665
4666    pub fn text_summary(&self) -> TextSummary {
4667        self.diff_transforms.summary().output
4668    }
4669
4670    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4671    where
4672        D: TextDimension,
4673        O: ToOffset,
4674    {
4675        let range = range.start.to_offset(self)..range.end.to_offset(self);
4676        let mut cursor = self
4677            .diff_transforms
4678            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4679        cursor.seek(&range.start, Bias::Right);
4680
4681        let Some(first_transform) = cursor.item() else {
4682            return D::from_text_summary(&TextSummary::default());
4683        };
4684
4685        let diff_transform_start = cursor.start().0;
4686        let diff_transform_end = cursor.end().0;
4687        let diff_start = range.start;
4688        let start_overshoot = diff_start - diff_transform_start;
4689        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4690
4691        let mut result = match first_transform {
4692            DiffTransform::BufferContent { .. } => {
4693                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4694                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4695                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4696            }
4697            DiffTransform::DeletedHunk {
4698                buffer_id,
4699                base_text_byte_range,
4700                has_trailing_newline,
4701                ..
4702            } => {
4703                let buffer_start = base_text_byte_range.start + start_overshoot;
4704                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4705                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4706                    panic!("{:?} is in non-existent deleted hunk", range.start)
4707                };
4708
4709                let include_trailing_newline =
4710                    *has_trailing_newline && range.end >= diff_transform_end;
4711                if include_trailing_newline {
4712                    buffer_end -= 1;
4713                }
4714
4715                let mut summary =
4716                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4717
4718                if include_trailing_newline {
4719                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4720                }
4721
4722                summary
4723            }
4724        };
4725        if range.end < diff_transform_end {
4726            return result;
4727        }
4728
4729        cursor.next();
4730        result.add_assign(&D::from_text_summary(
4731            &cursor.summary(&range.end, Bias::Right),
4732        ));
4733
4734        let Some(last_transform) = cursor.item() else {
4735            return result;
4736        };
4737
4738        let overshoot = range.end - cursor.start().0;
4739        let suffix = match last_transform {
4740            DiffTransform::BufferContent { .. } => {
4741                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4742                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4743            }
4744            DiffTransform::DeletedHunk {
4745                base_text_byte_range,
4746                buffer_id,
4747                has_trailing_newline,
4748                ..
4749            } => {
4750                let buffer_end = base_text_byte_range.start + overshoot;
4751                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4752                    panic!("{:?} is in non-existent deleted hunk", range.end)
4753                };
4754
4755                let mut suffix = base_text
4756                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4757                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4758                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4759                }
4760                suffix
4761            }
4762        };
4763
4764        result.add_assign(&suffix);
4765        result
4766    }
4767
4768    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4769    where
4770        D: TextDimension,
4771    {
4772        let mut summary = D::zero(());
4773        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4774        cursor.seek(&range.start, Bias::Right);
4775        if let Some(excerpt) = cursor.item() {
4776            let mut end_before_newline = cursor.end();
4777            if excerpt.has_trailing_newline {
4778                end_before_newline -= ExcerptOffset::new(1);
4779            }
4780
4781            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4782            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4783            let end_in_excerpt =
4784                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4785            summary.add_assign(
4786                &excerpt
4787                    .buffer
4788                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4789            );
4790
4791            if range.end > end_before_newline {
4792                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4793            }
4794
4795            cursor.next();
4796        }
4797
4798        if range.end > *cursor.start() {
4799            summary.add_assign(
4800                &cursor
4801                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4802                    .0,
4803            );
4804            if let Some(excerpt) = cursor.item() {
4805                range.end = cmp::max(*cursor.start(), range.end);
4806
4807                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4808                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4809                summary.add_assign(
4810                    &excerpt
4811                        .buffer
4812                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4813                );
4814            }
4815        }
4816
4817        summary
4818    }
4819
4820    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4821    where
4822        D: TextDimension + Ord + Sub<D, Output = D>,
4823    {
4824        self.summaries_for_anchors([anchor])[0]
4825    }
4826
4827    fn resolve_summary_for_anchor<D>(
4828        &self,
4829        anchor: &Anchor,
4830        excerpt_position: D,
4831        diff_transforms: &mut Cursor<
4832            DiffTransform,
4833            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4834        >,
4835    ) -> D
4836    where
4837        D: TextDimension + Ord + Sub<D, Output = D>,
4838    {
4839        loop {
4840            let transform_end_position = diff_transforms.end().0.0;
4841            let at_transform_end =
4842                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4843            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4844                diff_transforms.next();
4845                continue;
4846            }
4847
4848            let mut position = diff_transforms.start().1.0;
4849            match diff_transforms.item() {
4850                Some(DiffTransform::DeletedHunk {
4851                    buffer_id,
4852                    base_text_byte_range,
4853                    ..
4854                }) => {
4855                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4856                        && let Some(base_text) =
4857                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4858                        && base_text.can_resolve(diff_base_anchor)
4859                    {
4860                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4861                        if base_text_offset >= base_text_byte_range.start
4862                            && base_text_offset <= base_text_byte_range.end
4863                        {
4864                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4865                                base_text_byte_range.start..base_text_offset,
4866                            );
4867                            position.add_assign(&position_in_hunk);
4868                        } else if at_transform_end {
4869                            diff_transforms.next();
4870                            continue;
4871                        }
4872                    }
4873                }
4874                _ => {
4875                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4876                        diff_transforms.next();
4877                        continue;
4878                    }
4879                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4880                    position.add_assign(&overshoot);
4881                }
4882            }
4883
4884            return position;
4885        }
4886    }
4887
4888    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4889        let mut cursor = self
4890            .excerpts
4891            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4892        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4893
4894        cursor.seek(&Some(locator), Bias::Left);
4895        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4896            cursor.prev();
4897        }
4898
4899        let mut position = cursor.start().1;
4900        if let Some(excerpt) = cursor.item()
4901            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4902        {
4903            let excerpt_buffer_start = excerpt
4904                .buffer
4905                .offset_for_anchor(&excerpt.range.context.start);
4906            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4907            let buffer_position = cmp::min(
4908                excerpt_buffer_end,
4909                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4910            );
4911            if buffer_position > excerpt_buffer_start {
4912                position.value += buffer_position - excerpt_buffer_start;
4913            }
4914        }
4915        position
4916    }
4917
4918    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4919        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4920            excerpt_id = *replacement;
4921        }
4922        excerpt_id
4923    }
4924
4925    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4926    where
4927        D: TextDimension + Ord + Sub<D, Output = D>,
4928        I: 'a + IntoIterator<Item = &'a Anchor>,
4929    {
4930        let mut anchors = anchors.into_iter().peekable();
4931        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4932        let mut diff_transforms_cursor = self
4933            .diff_transforms
4934            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(());
4935        diff_transforms_cursor.next();
4936
4937        let mut summaries = Vec::new();
4938        while let Some(anchor) = anchors.peek() {
4939            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4940
4941            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4942                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4943            });
4944
4945            let locator = self.excerpt_locator_for_id(excerpt_id);
4946            cursor.seek_forward(locator, Bias::Left);
4947            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4948                cursor.prev();
4949            }
4950
4951            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4952            if let Some(excerpt) = cursor.item() {
4953                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4954                    let position = self.resolve_summary_for_anchor(
4955                        &Anchor::min(),
4956                        excerpt_start_position,
4957                        &mut diff_transforms_cursor,
4958                    );
4959                    summaries.extend(excerpt_anchors.map(|_| position));
4960                    continue;
4961                }
4962                let excerpt_buffer_start =
4963                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4964                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4965                for (buffer_summary, anchor) in excerpt
4966                    .buffer
4967                    .summaries_for_anchors_with_payload::<D, _, _>(
4968                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4969                    )
4970                {
4971                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4972                    let mut position = excerpt_start_position;
4973                    if summary > excerpt_buffer_start {
4974                        position.add_assign(&(summary - excerpt_buffer_start));
4975                    }
4976
4977                    if position > diff_transforms_cursor.start().0.0 {
4978                        diff_transforms_cursor
4979                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4980                    }
4981
4982                    summaries.push(self.resolve_summary_for_anchor(
4983                        anchor,
4984                        position,
4985                        &mut diff_transforms_cursor,
4986                    ));
4987                }
4988            } else {
4989                diff_transforms_cursor
4990                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4991                let position = self.resolve_summary_for_anchor(
4992                    &Anchor::max(),
4993                    excerpt_start_position,
4994                    &mut diff_transforms_cursor,
4995                );
4996                summaries.extend(excerpt_anchors.map(|_| position));
4997            }
4998        }
4999
5000        summaries
5001    }
5002
5003    pub fn dimensions_from_points<'a, D>(
5004        &'a self,
5005        points: impl 'a + IntoIterator<Item = Point>,
5006    ) -> impl 'a + Iterator<Item = D>
5007    where
5008        D: TextDimension + Sub<D, Output = D>,
5009    {
5010        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
5011        cursor.seek(&DimensionPair {
5012            key: Point::default(),
5013            value: None,
5014        });
5015        let mut points = points.into_iter();
5016        iter::from_fn(move || {
5017            let point = points.next()?;
5018
5019            cursor.seek_forward(&DimensionPair {
5020                key: point,
5021                value: None,
5022            });
5023
5024            if let Some(region) = cursor.region() {
5025                let overshoot = point - region.range.start.key;
5026                let buffer_point = region.buffer_range.start.key + overshoot;
5027                let mut position = region.range.start.value.unwrap();
5028                position.add_assign(
5029                    &region
5030                        .buffer
5031                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
5032                );
5033                if point == region.range.end.key && region.has_trailing_newline {
5034                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
5035                }
5036                Some(position)
5037            } else {
5038                Some(D::from_text_summary(&self.text_summary()))
5039            }
5040        })
5041    }
5042
5043    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5044    where
5045        I: 'a + IntoIterator<Item = &'a Anchor>,
5046    {
5047        let mut anchors = anchors.into_iter().enumerate().peekable();
5048        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5049        cursor.next();
5050
5051        let mut result = Vec::new();
5052
5053        while let Some((_, anchor)) = anchors.peek() {
5054            let old_excerpt_id = anchor.excerpt_id;
5055
5056            // Find the location where this anchor's excerpt should be.
5057            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5058            cursor.seek_forward(&Some(old_locator), Bias::Left);
5059
5060            let next_excerpt = cursor.item();
5061            let prev_excerpt = cursor.prev_item();
5062
5063            // Process all of the anchors for this excerpt.
5064            while let Some((anchor_ix, &anchor)) =
5065                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5066            {
5067                let mut anchor = anchor;
5068
5069                // Leave min and max anchors unchanged if invalid or
5070                // if the old excerpt still exists at this location
5071                let mut kept_position = next_excerpt
5072                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5073                    || old_excerpt_id == ExcerptId::max()
5074                    || old_excerpt_id == ExcerptId::min();
5075
5076                // If the old excerpt no longer exists at this location, then attempt to
5077                // find an equivalent position for this anchor in an adjacent excerpt.
5078                if !kept_position {
5079                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5080                        if excerpt.contains(&anchor) {
5081                            anchor.excerpt_id = excerpt.id;
5082                            kept_position = true;
5083                            break;
5084                        }
5085                    }
5086                }
5087
5088                // If there's no adjacent excerpt that contains the anchor's position,
5089                // then report that the anchor has lost its position.
5090                if !kept_position {
5091                    anchor = if let Some(excerpt) = next_excerpt {
5092                        let mut text_anchor = excerpt
5093                            .range
5094                            .context
5095                            .start
5096                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5097                        if text_anchor
5098                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5099                            .is_gt()
5100                        {
5101                            text_anchor = excerpt.range.context.end;
5102                        }
5103                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
5104                    } else if let Some(excerpt) = prev_excerpt {
5105                        let mut text_anchor = excerpt
5106                            .range
5107                            .context
5108                            .end
5109                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5110                        if text_anchor
5111                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5112                            .is_lt()
5113                        {
5114                            text_anchor = excerpt.range.context.start;
5115                        }
5116                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
5117                    } else if anchor.text_anchor.bias == Bias::Left {
5118                        Anchor::min()
5119                    } else {
5120                        Anchor::max()
5121                    };
5122                }
5123
5124                result.push((anchor_ix, anchor, kept_position));
5125            }
5126        }
5127        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5128        result
5129    }
5130
5131    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5132        self.anchor_at(position, Bias::Left)
5133    }
5134
5135    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5136        self.anchor_at(position, Bias::Right)
5137    }
5138
5139    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5140        let offset = position.to_offset(self);
5141
5142        // Find the given position in the diff transforms. Determine the corresponding
5143        // offset in the excerpts, and whether the position is within a deleted hunk.
5144        let mut diff_transforms = self
5145            .diff_transforms
5146            .cursor::<Dimensions<usize, ExcerptOffset>>(());
5147        diff_transforms.seek(&offset, Bias::Right);
5148
5149        if offset == diff_transforms.start().0
5150            && bias == Bias::Left
5151            && let Some(prev_item) = diff_transforms.prev_item()
5152            && let DiffTransform::DeletedHunk { .. } = prev_item
5153        {
5154            diff_transforms.prev();
5155        }
5156        let offset_in_transform = offset - diff_transforms.start().0;
5157        let mut excerpt_offset = diff_transforms.start().1;
5158        let mut diff_base_anchor = None;
5159        if let Some(DiffTransform::DeletedHunk {
5160            buffer_id,
5161            base_text_byte_range,
5162            has_trailing_newline,
5163            ..
5164        }) = diff_transforms.item()
5165        {
5166            let diff = self.diffs.get(buffer_id).expect("missing diff");
5167            if offset_in_transform > base_text_byte_range.len() {
5168                debug_assert!(*has_trailing_newline);
5169                bias = Bias::Right;
5170            } else {
5171                diff_base_anchor = Some(
5172                    diff.base_text()
5173                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5174                );
5175                bias = Bias::Left;
5176            }
5177        } else {
5178            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5179        };
5180
5181        let mut excerpts = self
5182            .excerpts
5183            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5184        excerpts.seek(&excerpt_offset, Bias::Right);
5185        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5186            excerpts.prev();
5187        }
5188        if let Some(excerpt) = excerpts.item() {
5189            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5190            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5191                overshoot -= 1;
5192                bias = Bias::Right;
5193            }
5194
5195            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5196            let text_anchor =
5197                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5198            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
5199            match diff_base_anchor {
5200                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5201                None => anchor,
5202            }
5203        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5204            Anchor::min()
5205        } else {
5206            Anchor::max()
5207        }
5208    }
5209
5210    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5211    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5212        let (excerpt, buffer, _) = self.as_singleton()?;
5213        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
5214    }
5215
5216    /// Returns an anchor for the given excerpt and text anchor,
5217    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5218    pub fn anchor_range_in_excerpt(
5219        &self,
5220        excerpt_id: ExcerptId,
5221        text_anchor: Range<text::Anchor>,
5222    ) -> Option<Range<Anchor>> {
5223        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5224        let excerpt = self.excerpt(excerpt_id)?;
5225
5226        Some(
5227            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
5228                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
5229        )
5230    }
5231
5232    /// Returns an anchor for the given excerpt and text anchor,
5233    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5234    pub fn anchor_in_excerpt(
5235        &self,
5236        excerpt_id: ExcerptId,
5237        text_anchor: text::Anchor,
5238    ) -> Option<Anchor> {
5239        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5240        let excerpt = self.excerpt(excerpt_id)?;
5241        self.anchor_in_excerpt_(excerpt, text_anchor)
5242    }
5243
5244    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5245        match text_anchor.buffer_id {
5246            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5247            Some(_) => return None,
5248            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
5249                return Some(Anchor::in_buffer(
5250                    excerpt.id,
5251                    excerpt.buffer_id,
5252                    text_anchor,
5253                ));
5254            }
5255            None => return None,
5256        }
5257
5258        let context = &excerpt.range.context;
5259        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5260            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5261        {
5262            return None;
5263        }
5264
5265        Some(Anchor::in_buffer(
5266            excerpt.id,
5267            excerpt.buffer_id,
5268            text_anchor,
5269        ))
5270    }
5271
5272    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5273        Some(self.excerpt(excerpt_id)?.range.context.clone())
5274    }
5275
5276    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5277        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5278            true
5279        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5280            excerpt.buffer.can_resolve(&anchor.text_anchor)
5281        } else {
5282            false
5283        }
5284    }
5285
5286    pub fn excerpts(
5287        &self,
5288    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5289        self.excerpts
5290            .iter()
5291            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5292    }
5293
5294    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
5295        let excerpts = self.excerpts.cursor(());
5296        let diff_transforms = self.diff_transforms.cursor(());
5297        MultiBufferCursor {
5298            excerpts,
5299            diff_transforms,
5300            diffs: &self.diffs,
5301            cached_region: None,
5302        }
5303    }
5304
5305    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5306        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5307        let mut excerpts = self
5308            .excerpts
5309            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(());
5310        excerpts.seek(&Some(start_locator), Bias::Left);
5311        excerpts.prev();
5312
5313        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(());
5314        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5315        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5316            diff_transforms.next();
5317        }
5318
5319        let excerpt = excerpts.item()?;
5320        Some(MultiBufferExcerpt {
5321            excerpt,
5322            offset: diff_transforms.start().output_dimension.0,
5323            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5324            excerpt_offset: excerpts.start().1.clone(),
5325            diff_transforms,
5326        })
5327    }
5328
5329    pub fn excerpt_boundaries_in_range<R, T>(
5330        &self,
5331        range: R,
5332    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5333    where
5334        R: RangeBounds<T>,
5335        T: ToOffset,
5336    {
5337        let start_offset;
5338        let start = match range.start_bound() {
5339            Bound::Included(start) => {
5340                start_offset = start.to_offset(self);
5341                Bound::Included(start_offset)
5342            }
5343            Bound::Excluded(_) => {
5344                panic!("not supported")
5345            }
5346            Bound::Unbounded => {
5347                start_offset = 0;
5348                Bound::Unbounded
5349            }
5350        };
5351        let end = match range.end_bound() {
5352            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5353            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5354            Bound::Unbounded => Bound::Unbounded,
5355        };
5356        let bounds = (start, end);
5357
5358        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5359        cursor.seek(&DimensionPair {
5360            key: start_offset,
5361            value: None,
5362        });
5363
5364        if cursor
5365            .region()
5366            .is_some_and(|region| bounds.contains(&region.range.start.key))
5367        {
5368            cursor.prev_excerpt();
5369        } else {
5370            cursor.seek_to_start_of_current_excerpt();
5371        }
5372        let mut prev_region = cursor.region();
5373
5374        cursor.next_excerpt();
5375
5376        iter::from_fn(move || {
5377            loop {
5378                if self.singleton {
5379                    return None;
5380                }
5381
5382                let next_region = cursor.region()?;
5383                cursor.next_excerpt();
5384                if !bounds.contains(&next_region.range.start.key) {
5385                    prev_region = Some(next_region);
5386                    continue;
5387                }
5388
5389                let next_region_start = next_region.range.start.value.unwrap();
5390                let next_region_end = if let Some(region) = cursor.region() {
5391                    region.range.start.value.unwrap()
5392                } else {
5393                    self.max_point()
5394                };
5395
5396                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5397                    id: region.excerpt.id,
5398                    buffer: region.excerpt.buffer.clone(),
5399                    buffer_id: region.excerpt.buffer_id,
5400                    range: region.excerpt.range.clone(),
5401                    end_row: MultiBufferRow(next_region_start.row),
5402                });
5403
5404                let next = ExcerptInfo {
5405                    id: next_region.excerpt.id,
5406                    buffer: next_region.excerpt.buffer.clone(),
5407                    buffer_id: next_region.excerpt.buffer_id,
5408                    range: next_region.excerpt.range.clone(),
5409                    end_row: if next_region.excerpt.has_trailing_newline {
5410                        MultiBufferRow(next_region_end.row - 1)
5411                    } else {
5412                        MultiBufferRow(next_region_end.row)
5413                    },
5414                };
5415
5416                let row = MultiBufferRow(next_region_start.row);
5417
5418                prev_region = Some(next_region);
5419
5420                return Some(ExcerptBoundary { row, prev, next });
5421            }
5422        })
5423    }
5424
5425    pub fn edit_count(&self) -> usize {
5426        self.edit_count
5427    }
5428
5429    pub fn non_text_state_update_count(&self) -> usize {
5430        self.non_text_state_update_count
5431    }
5432
5433    /// Returns the smallest enclosing bracket ranges containing the given range or
5434    /// None if no brackets contain range or the range is not contained in a single
5435    /// excerpt
5436    ///
5437    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5438    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5439        &self,
5440        range: Range<T>,
5441        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5442    ) -> Option<(Range<usize>, Range<usize>)> {
5443        let range = range.start.to_offset(self)..range.end.to_offset(self);
5444        let mut excerpt = self.excerpt_containing(range.clone())?;
5445        let buffer = excerpt.buffer();
5446        let excerpt_buffer_range = excerpt.buffer_range();
5447
5448        // Filter to ranges contained in the excerpt
5449        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5450            excerpt_buffer_range.contains(&open.start)
5451                && excerpt_buffer_range.contains(&close.end)
5452                && range_filter.is_none_or(|filter| filter(buffer, open, close))
5453        };
5454
5455        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5456            excerpt.map_range_to_buffer(range),
5457            Some(&range_filter),
5458        )?;
5459
5460        Some((
5461            excerpt.map_range_from_buffer(open),
5462            excerpt.map_range_from_buffer(close),
5463        ))
5464    }
5465
5466    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5467    /// not contained in a single excerpt
5468    pub fn enclosing_bracket_ranges<T: ToOffset>(
5469        &self,
5470        range: Range<T>,
5471    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5472        let range = range.start.to_offset(self)..range.end.to_offset(self);
5473        let mut excerpt = self.excerpt_containing(range.clone())?;
5474
5475        Some(
5476            excerpt
5477                .buffer()
5478                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5479                .filter_map(move |pair| {
5480                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5481                        Some((
5482                            excerpt.map_range_from_buffer(pair.open_range),
5483                            excerpt.map_range_from_buffer(pair.close_range),
5484                        ))
5485                    } else {
5486                        None
5487                    }
5488                }),
5489        )
5490    }
5491
5492    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5493    /// not contained in a single excerpt
5494    pub fn text_object_ranges<T: ToOffset>(
5495        &self,
5496        range: Range<T>,
5497        options: TreeSitterOptions,
5498    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5499        let range = range.start.to_offset(self)..range.end.to_offset(self);
5500        self.excerpt_containing(range.clone())
5501            .map(|mut excerpt| {
5502                excerpt
5503                    .buffer()
5504                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5505                    .filter_map(move |(range, text_object)| {
5506                        if excerpt.contains_buffer_range(range.clone()) {
5507                            Some((excerpt.map_range_from_buffer(range), text_object))
5508                        } else {
5509                            None
5510                        }
5511                    })
5512            })
5513            .into_iter()
5514            .flatten()
5515    }
5516
5517    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5518    /// not contained in a single excerpt
5519    pub fn bracket_ranges<T: ToOffset>(
5520        &self,
5521        range: Range<T>,
5522    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5523        let range = range.start.to_offset(self)..range.end.to_offset(self);
5524        let mut excerpt = self.excerpt_containing(range.clone())?;
5525
5526        Some(
5527            excerpt
5528                .buffer()
5529                .bracket_ranges(excerpt.map_range_to_buffer(range))
5530                .filter_map(move |pair| {
5531                    let buffer_range = pair.open_range.start..pair.close_range.end;
5532                    if excerpt.contains_buffer_range(buffer_range) {
5533                        Some((
5534                            excerpt.map_range_from_buffer(pair.open_range),
5535                            excerpt.map_range_from_buffer(pair.close_range),
5536                        ))
5537                    } else {
5538                        None
5539                    }
5540                }),
5541        )
5542    }
5543
5544    pub fn redacted_ranges<'a, T: ToOffset>(
5545        &'a self,
5546        range: Range<T>,
5547        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5548    ) -> impl Iterator<Item = Range<usize>> + 'a {
5549        let range = range.start.to_offset(self)..range.end.to_offset(self);
5550        self.lift_buffer_metadata(range, move |buffer, range| {
5551            if redaction_enabled(buffer.file()) {
5552                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5553            } else {
5554                None
5555            }
5556        })
5557        .map(|(range, _, _)| range)
5558    }
5559
5560    pub fn runnable_ranges(
5561        &self,
5562        range: Range<Anchor>,
5563    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5564        let range = range.start.to_offset(self)..range.end.to_offset(self);
5565        self.lift_buffer_metadata(range, move |buffer, range| {
5566            Some(
5567                buffer
5568                    .runnable_ranges(range.clone())
5569                    .filter(move |runnable| {
5570                        runnable.run_range.start >= range.start
5571                            && runnable.run_range.end < range.end
5572                    })
5573                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5574            )
5575        })
5576        .map(|(run_range, runnable, _)| language::RunnableRange {
5577            run_range,
5578            ..runnable
5579        })
5580    }
5581
5582    pub fn line_indents(
5583        &self,
5584        start_row: MultiBufferRow,
5585        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5586    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5587        let max_point = self.max_point();
5588        let mut cursor = self.cursor::<Point>();
5589        cursor.seek(&Point::new(start_row.0, 0));
5590        iter::from_fn(move || {
5591            let mut region = cursor.region()?;
5592            while !buffer_filter(&region.excerpt.buffer) {
5593                cursor.next();
5594                region = cursor.region()?;
5595            }
5596            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5597            let buffer_start_row =
5598                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5599
5600            let buffer_end_row = if region.is_main_buffer
5601                && (region.has_trailing_newline || region.range.end == max_point)
5602            {
5603                region.buffer_range.end.row
5604            } else {
5605                region.buffer_range.end.row.saturating_sub(1)
5606            };
5607
5608            let line_indents = region
5609                .buffer
5610                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5611            cursor.next();
5612            Some(line_indents.map(move |(buffer_row, indent)| {
5613                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5614                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5615            }))
5616        })
5617        .flatten()
5618    }
5619
5620    pub fn reversed_line_indents(
5621        &self,
5622        end_row: MultiBufferRow,
5623        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5624    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5625        let max_point = self.max_point();
5626        let mut cursor = self.cursor::<Point>();
5627        cursor.seek(&Point::new(end_row.0, 0));
5628        iter::from_fn(move || {
5629            let mut region = cursor.region()?;
5630            while !buffer_filter(&region.excerpt.buffer) {
5631                cursor.prev();
5632                region = cursor.region()?;
5633            }
5634
5635            let buffer_start_row = region.buffer_range.start.row;
5636            let buffer_end_row = if region.is_main_buffer
5637                && (region.has_trailing_newline || region.range.end == max_point)
5638            {
5639                region.buffer_range.end.row + 1
5640            } else {
5641                region.buffer_range.end.row
5642            };
5643
5644            let overshoot = end_row.0 - region.range.start.row;
5645            let buffer_end_row =
5646                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5647
5648            let line_indents = region
5649                .buffer
5650                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5651            cursor.prev();
5652            Some(line_indents.map(move |(buffer_row, indent)| {
5653                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5654                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5655            }))
5656        })
5657        .flatten()
5658    }
5659
5660    pub async fn enclosing_indent(
5661        &self,
5662        mut target_row: MultiBufferRow,
5663    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5664        let max_row = MultiBufferRow(self.max_point().row);
5665        if target_row >= max_row {
5666            return None;
5667        }
5668
5669        let mut target_indent = self.line_indent_for_row(target_row);
5670
5671        // If the current row is at the start of an indented block, we want to return this
5672        // block as the enclosing indent.
5673        if !target_indent.is_line_empty() && target_row < max_row {
5674            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5675            if !next_line_indent.is_line_empty()
5676                && target_indent.raw_len() < next_line_indent.raw_len()
5677            {
5678                target_indent = next_line_indent;
5679                target_row.0 += 1;
5680            }
5681        }
5682
5683        const SEARCH_ROW_LIMIT: u32 = 25000;
5684        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5685        const YIELD_INTERVAL: u32 = 100;
5686
5687        let mut accessed_row_counter = 0;
5688
5689        // If there is a blank line at the current row, search for the next non indented lines
5690        if target_indent.is_line_empty() {
5691            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5692            let end =
5693                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5694
5695            let mut non_empty_line_above = None;
5696            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5697                if row < start {
5698                    break;
5699                }
5700                accessed_row_counter += 1;
5701                if accessed_row_counter == YIELD_INTERVAL {
5702                    accessed_row_counter = 0;
5703                    yield_now().await;
5704                }
5705                if !indent.is_line_empty() {
5706                    non_empty_line_above = Some((row, indent));
5707                    break;
5708                }
5709            }
5710
5711            let mut non_empty_line_below = None;
5712            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5713                if row > end {
5714                    break;
5715                }
5716                accessed_row_counter += 1;
5717                if accessed_row_counter == YIELD_INTERVAL {
5718                    accessed_row_counter = 0;
5719                    yield_now().await;
5720                }
5721                if !indent.is_line_empty() {
5722                    non_empty_line_below = Some((row, indent));
5723                    break;
5724                }
5725            }
5726
5727            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5728                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5729                    if above_indent.raw_len() >= below_indent.raw_len() {
5730                        (above_row, above_indent)
5731                    } else {
5732                        (below_row, below_indent)
5733                    }
5734                }
5735                (Some(above), None) => above,
5736                (None, Some(below)) => below,
5737                _ => return None,
5738            };
5739
5740            target_indent = indent;
5741            target_row = row;
5742        }
5743
5744        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5745        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5746
5747        let mut start_indent = None;
5748        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5749            if row < start {
5750                break;
5751            }
5752            accessed_row_counter += 1;
5753            if accessed_row_counter == YIELD_INTERVAL {
5754                accessed_row_counter = 0;
5755                yield_now().await;
5756            }
5757            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5758                start_indent = Some((row, indent));
5759                break;
5760            }
5761        }
5762        let (start_row, start_indent_size) = start_indent?;
5763
5764        let mut end_indent = (end, None);
5765        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5766            if row > end {
5767                break;
5768            }
5769            accessed_row_counter += 1;
5770            if accessed_row_counter == YIELD_INTERVAL {
5771                accessed_row_counter = 0;
5772                yield_now().await;
5773            }
5774            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5775                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5776                break;
5777            }
5778        }
5779        let (end_row, end_indent_size) = end_indent;
5780
5781        let indent = if let Some(end_indent_size) = end_indent_size {
5782            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5783                start_indent_size
5784            } else {
5785                end_indent_size
5786            }
5787        } else {
5788            start_indent_size
5789        };
5790
5791        Some((start_row..end_row, indent))
5792    }
5793
5794    pub fn indent_guides_in_range<T: ToPoint>(
5795        &self,
5796        range: Range<T>,
5797        ignore_disabled_for_language: bool,
5798        cx: &App,
5799    ) -> impl Iterator<Item = IndentGuide> {
5800        let range = range.start.to_point(self)..range.end.to_point(self);
5801        let start_row = MultiBufferRow(range.start.row);
5802        let end_row = MultiBufferRow(range.end.row);
5803
5804        let mut row_indents = self.line_indents(start_row, |buffer| {
5805            let settings =
5806                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5807            settings.indent_guides.enabled || ignore_disabled_for_language
5808        });
5809
5810        let mut result = Vec::new();
5811        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5812
5813        let mut prev_settings = None;
5814        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5815            if first_row > end_row {
5816                break;
5817            }
5818            let current_depth = indent_stack.len() as u32;
5819
5820            // Avoid retrieving the language settings repeatedly for every buffer row.
5821            if let Some((prev_buffer_id, _)) = &prev_settings
5822                && prev_buffer_id != &buffer.remote_id()
5823            {
5824                prev_settings.take();
5825            }
5826            let settings = &prev_settings
5827                .get_or_insert_with(|| {
5828                    (
5829                        buffer.remote_id(),
5830                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5831                    )
5832                })
5833                .1;
5834            let tab_size = settings.tab_size.get();
5835
5836            // When encountering empty, continue until found useful line indent
5837            // then add to the indent stack with the depth found
5838            let mut found_indent = false;
5839            let mut last_row = first_row;
5840            if line_indent.is_line_blank() {
5841                while !found_indent {
5842                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5843                        break;
5844                    };
5845                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5846                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5847                        break;
5848                    }
5849
5850                    if new_line_indent.is_line_blank() {
5851                        continue;
5852                    }
5853                    last_row = target_row.min(end_row);
5854                    line_indent = new_line_indent;
5855                    found_indent = true;
5856                    break;
5857                }
5858            } else {
5859                found_indent = true
5860            }
5861
5862            let depth = if found_indent {
5863                line_indent.len(tab_size) / tab_size
5864            } else {
5865                0
5866            };
5867
5868            match depth.cmp(&current_depth) {
5869                cmp::Ordering::Less => {
5870                    for _ in 0..(current_depth - depth) {
5871                        let mut indent = indent_stack.pop().unwrap();
5872                        if last_row != first_row {
5873                            // In this case, we landed on an empty row, had to seek forward,
5874                            // and discovered that the indent we where on is ending.
5875                            // This means that the last display row must
5876                            // be on line that ends this indent range, so we
5877                            // should display the range up to the first non-empty line
5878                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5879                        }
5880
5881                        result.push(indent)
5882                    }
5883                }
5884                cmp::Ordering::Greater => {
5885                    for next_depth in current_depth..depth {
5886                        indent_stack.push(IndentGuide {
5887                            buffer_id: buffer.remote_id(),
5888                            start_row: first_row,
5889                            end_row: last_row,
5890                            depth: next_depth,
5891                            tab_size,
5892                            settings: settings.indent_guides.clone(),
5893                        });
5894                    }
5895                }
5896                _ => {}
5897            }
5898
5899            for indent in indent_stack.iter_mut() {
5900                indent.end_row = last_row;
5901            }
5902        }
5903
5904        result.extend(indent_stack);
5905        result.into_iter()
5906    }
5907
5908    pub fn trailing_excerpt_update_count(&self) -> usize {
5909        self.trailing_excerpt_update_count
5910    }
5911
5912    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5913        self.point_to_buffer_offset(point)
5914            .and_then(|(buffer, _)| buffer.file())
5915    }
5916
5917    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5918        self.point_to_buffer_offset(point)
5919            .and_then(|(buffer, offset)| buffer.language_at(offset))
5920    }
5921
5922    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5923        self.excerpts
5924            .first()
5925            .map(|excerpt| &excerpt.buffer)
5926            .map(|buffer| {
5927                language_settings(
5928                    buffer.language().map(|language| language.name()),
5929                    buffer.file(),
5930                    cx,
5931                )
5932            })
5933            .unwrap_or_else(move || self.language_settings_at(0, cx))
5934    }
5935
5936    pub fn language_settings_at<'a, T: ToOffset>(
5937        &'a self,
5938        point: T,
5939        cx: &'a App,
5940    ) -> Cow<'a, LanguageSettings> {
5941        let mut language = None;
5942        let mut file = None;
5943        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5944            language = buffer.language_at(offset);
5945            file = buffer.file();
5946        }
5947        language_settings(language.map(|l| l.name()), file, cx)
5948    }
5949
5950    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5951        self.point_to_buffer_offset(point)
5952            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5953    }
5954
5955    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5956        self.point_to_buffer_offset(point)
5957            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5958            .unwrap_or_default()
5959    }
5960
5961    pub fn language_indent_size_at<T: ToOffset>(
5962        &self,
5963        position: T,
5964        cx: &App,
5965    ) -> Option<IndentSize> {
5966        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5967        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5968    }
5969
5970    pub fn is_dirty(&self) -> bool {
5971        self.is_dirty
5972    }
5973
5974    pub fn has_deleted_file(&self) -> bool {
5975        self.has_deleted_file
5976    }
5977
5978    pub fn has_conflict(&self) -> bool {
5979        self.has_conflict
5980    }
5981
5982    pub fn has_diagnostics(&self) -> bool {
5983        self.excerpts
5984            .iter()
5985            .any(|excerpt| excerpt.buffer.has_diagnostics())
5986    }
5987
5988    pub fn diagnostic_group(
5989        &self,
5990        buffer_id: BufferId,
5991        group_id: usize,
5992    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5993        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
5994            if buffer.remote_id() != buffer_id {
5995                return None;
5996            };
5997            Some(
5998                buffer
5999                    .diagnostics_in_range(range, false)
6000                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6001                    .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6002            )
6003        })
6004        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6005    }
6006
6007    pub fn diagnostics_in_range<'a, T>(
6008        &'a self,
6009        range: Range<T>,
6010    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, T>> + 'a
6011    where
6012        T: 'a
6013            + text::ToOffset
6014            + text::FromAnchor
6015            + TextDimension
6016            + Ord
6017            + Sub<T, Output = T>
6018            + fmt::Debug,
6019    {
6020        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6021            Some(
6022                buffer
6023                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6024                    .map(|entry| (entry.range, entry.diagnostic)),
6025            )
6026        })
6027        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6028    }
6029
6030    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
6031        &'a self,
6032        range: Range<T>,
6033    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, T>)> + 'a
6034    where
6035        T: 'a
6036            + text::ToOffset
6037            + text::FromAnchor
6038            + TextDimension
6039            + Ord
6040            + Sub<T, Output = T>
6041            + fmt::Debug,
6042    {
6043        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6044            Some(
6045                buffer
6046                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6047                    .map(|entry| (entry.range, entry.diagnostic)),
6048            )
6049        })
6050        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6051    }
6052
6053    pub fn syntax_ancestor<T: ToOffset>(
6054        &self,
6055        range: Range<T>,
6056    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
6057        let range = range.start.to_offset(self)..range.end.to_offset(self);
6058        let mut excerpt = self.excerpt_containing(range.clone())?;
6059        let node = excerpt
6060            .buffer()
6061            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6062        let node_range = node.byte_range();
6063        if !excerpt.contains_buffer_range(node_range.clone()) {
6064            return None;
6065        };
6066        Some((node, excerpt.map_range_from_buffer(node_range)))
6067    }
6068
6069    pub fn syntax_next_sibling<T: ToOffset>(
6070        &self,
6071        range: Range<T>,
6072    ) -> Option<tree_sitter::Node<'_>> {
6073        let range = range.start.to_offset(self)..range.end.to_offset(self);
6074        let mut excerpt = self.excerpt_containing(range.clone())?;
6075        excerpt
6076            .buffer()
6077            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
6078    }
6079
6080    pub fn syntax_prev_sibling<T: ToOffset>(
6081        &self,
6082        range: Range<T>,
6083    ) -> Option<tree_sitter::Node<'_>> {
6084        let range = range.start.to_offset(self)..range.end.to_offset(self);
6085        let mut excerpt = self.excerpt_containing(range.clone())?;
6086        excerpt
6087            .buffer()
6088            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
6089    }
6090
6091    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6092        let (excerpt_id, _, buffer) = self.as_singleton()?;
6093        let outline = buffer.outline(theme);
6094        Some(Outline::new(
6095            outline
6096                .items
6097                .into_iter()
6098                .flat_map(|item| {
6099                    Some(OutlineItem {
6100                        depth: item.depth,
6101                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6102                        text: item.text,
6103                        highlight_ranges: item.highlight_ranges,
6104                        name_ranges: item.name_ranges,
6105                        body_range: item.body_range.and_then(|body_range| {
6106                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6107                        }),
6108                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6109                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6110                        }),
6111                    })
6112                })
6113                .collect(),
6114        ))
6115    }
6116
6117    pub fn symbols_containing<T: ToOffset>(
6118        &self,
6119        offset: T,
6120        theme: Option<&SyntaxTheme>,
6121    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6122        let anchor = self.anchor_before(offset);
6123        let excerpt_id = anchor.excerpt_id;
6124        let excerpt = self.excerpt(excerpt_id)?;
6125        let buffer_id = excerpt.buffer_id;
6126        Some((
6127            buffer_id,
6128            excerpt
6129                .buffer
6130                .symbols_containing(anchor.text_anchor, theme)
6131                .into_iter()
6132                .flat_map(|item| {
6133                    Some(OutlineItem {
6134                        depth: item.depth,
6135                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
6136                        text: item.text,
6137                        highlight_ranges: item.highlight_ranges,
6138                        name_ranges: item.name_ranges,
6139                        body_range: item.body_range.map(|body_range| {
6140                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
6141                        }),
6142                        annotation_range: item.annotation_range.map(|body_range| {
6143                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
6144                        }),
6145                    })
6146                })
6147                .collect(),
6148        ))
6149    }
6150
6151    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6152        if id == ExcerptId::min() {
6153            Locator::min_ref()
6154        } else if id == ExcerptId::max() {
6155            Locator::max_ref()
6156        } else {
6157            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6158            if let Some(entry) = item
6159                && entry.id == id
6160            {
6161                return &entry.locator;
6162            }
6163            panic!("invalid excerpt id {id:?}")
6164        }
6165    }
6166
6167    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6168    fn excerpt_locators_for_ids(
6169        &self,
6170        ids: impl IntoIterator<Item = ExcerptId>,
6171    ) -> SmallVec<[Locator; 1]> {
6172        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6173        sorted_ids.sort_unstable();
6174        let mut locators = SmallVec::new();
6175
6176        while sorted_ids.last() == Some(&ExcerptId::max()) {
6177            sorted_ids.pop();
6178            if let Some(mapping) = self.excerpt_ids.last() {
6179                locators.push(mapping.locator.clone());
6180            }
6181        }
6182
6183        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6184        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6185            sorted_ids.next();
6186            if let Some(mapping) = self.excerpt_ids.first() {
6187                locators.push(mapping.locator.clone());
6188            }
6189        }
6190
6191        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6192        for id in sorted_ids {
6193            if cursor.seek_forward(&id, Bias::Left) {
6194                locators.push(cursor.item().unwrap().locator.clone());
6195            } else {
6196                panic!("invalid excerpt id {:?}", id);
6197            }
6198        }
6199
6200        locators.sort_unstable();
6201        locators
6202    }
6203
6204    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6205        Some(self.excerpt(excerpt_id)?.buffer_id)
6206    }
6207
6208    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6209        Some(&self.excerpt(excerpt_id)?.buffer)
6210    }
6211
6212    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6213        let mut cursor = self
6214            .excerpts
6215            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
6216        let locator = self.excerpt_locator_for_id(excerpt_id);
6217        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6218        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6219            sought_exact = true;
6220            cursor.prev();
6221        } else if excerpt_id == ExcerptId::min() {
6222            sought_exact = true;
6223        }
6224        if sought_exact {
6225            let start = cursor.start().1.clone();
6226            let end = cursor.end().1;
6227            let mut diff_transforms = self
6228                .diff_transforms
6229                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
6230            diff_transforms.seek(&start, Bias::Left);
6231            let overshoot = start.0 - diff_transforms.start().0.0;
6232            let start = diff_transforms.start().1.0 + overshoot;
6233            diff_transforms.seek(&end, Bias::Right);
6234            let overshoot = end.0 - diff_transforms.start().0.0;
6235            let end = diff_transforms.start().1.0 + overshoot;
6236            Some(start..end)
6237        } else {
6238            None
6239        }
6240    }
6241
6242    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6243        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6244        let locator = self.excerpt_locator_for_id(excerpt_id);
6245        cursor.seek(&Some(locator), Bias::Left);
6246        if let Some(excerpt) = cursor.item()
6247            && excerpt.id == excerpt_id
6248        {
6249            return Some(excerpt);
6250        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6251            cursor.prev();
6252            return cursor.item();
6253        }
6254        None
6255    }
6256
6257    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6258    pub fn excerpt_containing<T: ToOffset>(
6259        &self,
6260        range: Range<T>,
6261    ) -> Option<MultiBufferExcerpt<'_>> {
6262        let range = range.start.to_offset(self)..range.end.to_offset(self);
6263        let mut cursor = self.cursor::<usize>();
6264        cursor.seek(&range.start);
6265
6266        let start_excerpt = cursor.excerpt()?;
6267        if range.end != range.start {
6268            cursor.seek_forward(&range.end);
6269            if cursor.excerpt()?.id != start_excerpt.id {
6270                return None;
6271            }
6272        }
6273
6274        cursor.seek_to_start_of_current_excerpt();
6275        let region = cursor.region()?;
6276        let offset = region.range.start;
6277        let buffer_offset = start_excerpt.buffer_start_offset();
6278        let excerpt_offset = cursor.excerpts.start().clone();
6279        Some(MultiBufferExcerpt {
6280            diff_transforms: cursor.diff_transforms,
6281            excerpt: start_excerpt,
6282            offset,
6283            buffer_offset,
6284            excerpt_offset,
6285        })
6286    }
6287
6288    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6289        if let Some(id) = anchor.buffer_id {
6290            return Some(id);
6291        }
6292        let excerpt = self.excerpt_containing(anchor..anchor)?;
6293        Some(excerpt.buffer_id())
6294    }
6295
6296    pub fn selections_in_range<'a>(
6297        &'a self,
6298        range: &'a Range<Anchor>,
6299        include_local: bool,
6300    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6301        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6302        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6303        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6304        cursor.seek(start_locator, Bias::Left);
6305        cursor
6306            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6307            .flat_map(move |excerpt| {
6308                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6309                if excerpt.id == range.start.excerpt_id {
6310                    query_range.start = range.start.text_anchor;
6311                }
6312                if excerpt.id == range.end.excerpt_id {
6313                    query_range.end = range.end.text_anchor;
6314                }
6315
6316                excerpt
6317                    .buffer
6318                    .selections_in_range(query_range, include_local)
6319                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6320                        selections.map(move |selection| {
6321                            let mut start =
6322                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
6323                            let mut end =
6324                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
6325                            if range.start.cmp(&start, self).is_gt() {
6326                                start = range.start;
6327                            }
6328                            if range.end.cmp(&end, self).is_lt() {
6329                                end = range.end;
6330                            }
6331
6332                            (
6333                                replica_id,
6334                                line_mode,
6335                                cursor_shape,
6336                                Selection {
6337                                    id: selection.id,
6338                                    start,
6339                                    end,
6340                                    reversed: selection.reversed,
6341                                    goal: selection.goal,
6342                                },
6343                            )
6344                        })
6345                    })
6346            })
6347    }
6348
6349    pub fn show_headers(&self) -> bool {
6350        self.show_headers
6351    }
6352
6353    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6354        self.diffs.get(&buffer_id)
6355    }
6356
6357    /// Visually annotates a position or range with the `Debug` representation of a value. The
6358    /// callsite of this function is used as a key - previous annotations will be removed.
6359    #[cfg(debug_assertions)]
6360    #[track_caller]
6361    pub fn debug<V, R>(&self, ranges: &R, value: V)
6362    where
6363        R: debug::ToMultiBufferDebugRanges,
6364        V: std::fmt::Debug,
6365    {
6366        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6367    }
6368
6369    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6370    /// debug annotations with the same key will be removed. The key is also used to determine the
6371    /// annotation's color.
6372    #[cfg(debug_assertions)]
6373    #[track_caller]
6374    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6375    where
6376        K: std::hash::Hash + 'static,
6377        R: debug::ToMultiBufferDebugRanges,
6378        V: std::fmt::Debug,
6379    {
6380        let text_ranges = ranges
6381            .to_multi_buffer_debug_ranges(self)
6382            .into_iter()
6383            .flat_map(|range| {
6384                self.range_to_buffer_ranges(range).into_iter().map(
6385                    |(buffer, range, _excerpt_id)| {
6386                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6387                    },
6388                )
6389            })
6390            .collect();
6391        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6392            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6393        });
6394    }
6395
6396    // used by line_mode selections and tries to match vim behavior
6397    pub fn expand_to_line(&self, range: Range<Point>) -> Range<Point> {
6398        let new_start = MultiBufferPoint::new(range.start.row, 0);
6399        let new_end = if range.end.column > 0 {
6400            MultiBufferPoint::new(range.end.row, self.line_len(MultiBufferRow(range.end.row)))
6401        } else {
6402            range.end
6403        };
6404        new_start..new_end
6405    }
6406}
6407
6408#[cfg(any(test, feature = "test-support"))]
6409impl MultiBufferSnapshot {
6410    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6411        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6412        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6413        start..end
6414    }
6415
6416    #[cfg(any(test, feature = "test-support"))]
6417    fn check_invariants(&self) {
6418        let excerpts = self.excerpts.items(());
6419        let excerpt_ids = self.excerpt_ids.items(());
6420
6421        for (ix, excerpt) in excerpts.iter().enumerate() {
6422            if ix == 0 {
6423                if excerpt.locator <= Locator::min() {
6424                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6425                }
6426            } else if excerpt.locator <= excerpts[ix - 1].locator {
6427                panic!("excerpts are out-of-order: {:?}", excerpts);
6428            }
6429        }
6430
6431        for (ix, entry) in excerpt_ids.iter().enumerate() {
6432            if ix == 0 {
6433                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6434                    panic!("invalid first excerpt id {:?}", entry.id);
6435                }
6436            } else if entry.id <= excerpt_ids[ix - 1].id {
6437                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6438            }
6439        }
6440
6441        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6442            panic!(
6443                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6444                self.excerpts.summary().text.len,
6445                self.diff_transforms.summary().input,
6446                self.diff_transforms.items(()),
6447            );
6448        }
6449
6450        let mut prev_transform: Option<&DiffTransform> = None;
6451        for item in self.diff_transforms.iter() {
6452            if let DiffTransform::BufferContent {
6453                summary,
6454                inserted_hunk_info,
6455            } = item
6456            {
6457                if let Some(DiffTransform::BufferContent {
6458                    inserted_hunk_info: prev_inserted_hunk_info,
6459                    ..
6460                }) = prev_transform
6461                    && *inserted_hunk_info == *prev_inserted_hunk_info
6462                {
6463                    panic!(
6464                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6465                        self.diff_transforms.items(())
6466                    );
6467                }
6468                if summary.len == 0 && !self.is_empty() {
6469                    panic!("empty buffer content transform");
6470                }
6471            }
6472            prev_transform = Some(item);
6473        }
6474    }
6475}
6476
6477impl<'a, D> MultiBufferCursor<'a, D>
6478where
6479    D: TextDimension + Ord + Sub<D, Output = D>,
6480{
6481    fn seek(&mut self, position: &D) {
6482        self.cached_region.take();
6483        self.diff_transforms
6484            .seek(&OutputDimension(*position), Bias::Right);
6485        if self.diff_transforms.item().is_none()
6486            && *position == self.diff_transforms.start().output_dimension.0
6487        {
6488            self.diff_transforms.prev();
6489        }
6490
6491        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6492        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6493            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6494            excerpt_position.add_assign(&overshoot);
6495        }
6496
6497        self.excerpts
6498            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
6499        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6500            self.excerpts.prev();
6501        }
6502    }
6503
6504    fn seek_forward(&mut self, position: &D) {
6505        self.cached_region.take();
6506        self.diff_transforms
6507            .seek_forward(&OutputDimension(*position), Bias::Right);
6508        if self.diff_transforms.item().is_none()
6509            && *position == self.diff_transforms.start().output_dimension.0
6510        {
6511            self.diff_transforms.prev();
6512        }
6513
6514        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6515        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6516        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6517            excerpt_position.add_assign(&overshoot);
6518        }
6519
6520        self.excerpts
6521            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
6522        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6523            self.excerpts.prev();
6524        }
6525    }
6526
6527    fn next_excerpt(&mut self) {
6528        self.excerpts.next();
6529        self.seek_to_start_of_current_excerpt();
6530    }
6531
6532    fn prev_excerpt(&mut self) {
6533        self.excerpts.prev();
6534        self.seek_to_start_of_current_excerpt();
6535    }
6536
6537    fn seek_to_start_of_current_excerpt(&mut self) {
6538        self.cached_region.take();
6539        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6540        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6541            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6542            && self.diff_transforms.next_item().is_some()
6543        {
6544            self.diff_transforms.next();
6545        }
6546    }
6547
6548    fn next(&mut self) {
6549        self.cached_region.take();
6550        match self
6551            .diff_transforms
6552            .end()
6553            .excerpt_dimension
6554            .cmp(&self.excerpts.end())
6555        {
6556            cmp::Ordering::Less => self.diff_transforms.next(),
6557            cmp::Ordering::Greater => self.excerpts.next(),
6558            cmp::Ordering::Equal => {
6559                self.diff_transforms.next();
6560                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6561                    || self.diff_transforms.item().is_none()
6562                {
6563                    self.excerpts.next();
6564                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6565                    self.diff_transforms.item()
6566                    && self
6567                        .excerpts
6568                        .item()
6569                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6570                {
6571                    self.excerpts.next();
6572                }
6573            }
6574        }
6575    }
6576
6577    fn prev(&mut self) {
6578        self.cached_region.take();
6579        match self
6580            .diff_transforms
6581            .start()
6582            .excerpt_dimension
6583            .cmp(self.excerpts.start())
6584        {
6585            cmp::Ordering::Less => self.excerpts.prev(),
6586            cmp::Ordering::Greater => self.diff_transforms.prev(),
6587            cmp::Ordering::Equal => {
6588                self.diff_transforms.prev();
6589                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6590                    || self.diff_transforms.item().is_none()
6591                {
6592                    self.excerpts.prev();
6593                }
6594            }
6595        }
6596    }
6597
6598    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6599        if self.cached_region.is_none() {
6600            self.cached_region = self.build_region();
6601        }
6602        self.cached_region.clone()
6603    }
6604
6605    fn is_at_start_of_excerpt(&mut self) -> bool {
6606        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6607            return false;
6608        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6609            return true;
6610        }
6611
6612        self.diff_transforms.prev();
6613        let prev_transform = self.diff_transforms.item();
6614        self.diff_transforms.next();
6615
6616        prev_transform.is_none_or(|next_transform| {
6617            matches!(next_transform, DiffTransform::BufferContent { .. })
6618        })
6619    }
6620
6621    fn is_at_end_of_excerpt(&mut self) -> bool {
6622        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6623            return false;
6624        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6625            || self.diff_transforms.item().is_none()
6626        {
6627            return true;
6628        }
6629
6630        let next_transform = self.diff_transforms.next_item();
6631        next_transform.is_none_or(|next_transform| match next_transform {
6632            DiffTransform::BufferContent { .. } => true,
6633            DiffTransform::DeletedHunk { hunk_info, .. } => self
6634                .excerpts
6635                .item()
6636                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6637        })
6638    }
6639
6640    fn main_buffer_position(&self) -> Option<D> {
6641        let excerpt = self.excerpts.item()?;
6642        let buffer = &excerpt.buffer;
6643        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6644        let mut buffer_start = buffer_context_start;
6645        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6646        buffer_start.add_assign(&overshoot);
6647        Some(buffer_start)
6648    }
6649
6650    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6651        let excerpt = self.excerpts.item()?;
6652        match self.diff_transforms.item()? {
6653            DiffTransform::DeletedHunk {
6654                buffer_id,
6655                base_text_byte_range,
6656                has_trailing_newline,
6657                hunk_info,
6658                ..
6659            } => {
6660                let diff = self.diffs.get(buffer_id)?;
6661                let buffer = diff.base_text();
6662                let mut rope_cursor = buffer.as_rope().cursor(0);
6663                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6664                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6665                let mut buffer_end = buffer_start;
6666                buffer_end.add_assign(&buffer_range_len);
6667                let start = self.diff_transforms.start().output_dimension.0;
6668                let end = self.diff_transforms.end().output_dimension.0;
6669                Some(MultiBufferRegion {
6670                    buffer,
6671                    excerpt,
6672                    has_trailing_newline: *has_trailing_newline,
6673                    is_main_buffer: false,
6674                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6675                        hunk_info.hunk_secondary_status,
6676                    )),
6677                    buffer_range: buffer_start..buffer_end,
6678                    range: start..end,
6679                })
6680            }
6681            DiffTransform::BufferContent {
6682                inserted_hunk_info, ..
6683            } => {
6684                let buffer = &excerpt.buffer;
6685                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6686
6687                let mut start = self.diff_transforms.start().output_dimension.0;
6688                let mut buffer_start = buffer_context_start;
6689                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6690                    let overshoot =
6691                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6692                    start.add_assign(&overshoot);
6693                } else {
6694                    let overshoot =
6695                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6696                    buffer_start.add_assign(&overshoot);
6697                }
6698
6699                let mut end;
6700                let mut buffer_end;
6701                let has_trailing_newline;
6702                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6703                    let overshoot =
6704                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6705                    end = self.diff_transforms.end().output_dimension.0;
6706                    buffer_end = buffer_context_start;
6707                    buffer_end.add_assign(&overshoot);
6708                    has_trailing_newline = false;
6709                } else {
6710                    let overshoot =
6711                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6712                    end = self.diff_transforms.start().output_dimension.0;
6713                    end.add_assign(&overshoot);
6714                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6715                    has_trailing_newline = excerpt.has_trailing_newline;
6716                };
6717
6718                Some(MultiBufferRegion {
6719                    buffer,
6720                    excerpt,
6721                    has_trailing_newline,
6722                    is_main_buffer: true,
6723                    diff_hunk_status: inserted_hunk_info
6724                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6725                    buffer_range: buffer_start..buffer_end,
6726                    range: start..end,
6727                })
6728            }
6729        }
6730    }
6731
6732    fn excerpt(&self) -> Option<&'a Excerpt> {
6733        self.excerpts.item()
6734    }
6735}
6736
6737impl History {
6738    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6739        self.transaction_depth += 1;
6740        if self.transaction_depth == 1 {
6741            let id = self.next_transaction_id.tick();
6742            self.undo_stack.push(Transaction {
6743                id,
6744                buffer_transactions: Default::default(),
6745                first_edit_at: now,
6746                last_edit_at: now,
6747                suppress_grouping: false,
6748            });
6749            Some(id)
6750        } else {
6751            None
6752        }
6753    }
6754
6755    fn end_transaction(
6756        &mut self,
6757        now: Instant,
6758        buffer_transactions: HashMap<BufferId, TransactionId>,
6759    ) -> bool {
6760        assert_ne!(self.transaction_depth, 0);
6761        self.transaction_depth -= 1;
6762        if self.transaction_depth == 0 {
6763            if buffer_transactions.is_empty() {
6764                self.undo_stack.pop();
6765                false
6766            } else {
6767                self.redo_stack.clear();
6768                let transaction = self.undo_stack.last_mut().unwrap();
6769                transaction.last_edit_at = now;
6770                for (buffer_id, transaction_id) in buffer_transactions {
6771                    transaction
6772                        .buffer_transactions
6773                        .entry(buffer_id)
6774                        .or_insert(transaction_id);
6775                }
6776                true
6777            }
6778        } else {
6779            false
6780        }
6781    }
6782
6783    fn push_transaction<'a, T>(
6784        &mut self,
6785        buffer_transactions: T,
6786        now: Instant,
6787        cx: &Context<MultiBuffer>,
6788    ) where
6789        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6790    {
6791        assert_eq!(self.transaction_depth, 0);
6792        let transaction = Transaction {
6793            id: self.next_transaction_id.tick(),
6794            buffer_transactions: buffer_transactions
6795                .into_iter()
6796                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6797                .collect(),
6798            first_edit_at: now,
6799            last_edit_at: now,
6800            suppress_grouping: false,
6801        };
6802        if !transaction.buffer_transactions.is_empty() {
6803            self.undo_stack.push(transaction);
6804            self.redo_stack.clear();
6805        }
6806    }
6807
6808    fn finalize_last_transaction(&mut self) {
6809        if let Some(transaction) = self.undo_stack.last_mut() {
6810            transaction.suppress_grouping = true;
6811        }
6812    }
6813
6814    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6815        if let Some(ix) = self
6816            .undo_stack
6817            .iter()
6818            .rposition(|transaction| transaction.id == transaction_id)
6819        {
6820            Some(self.undo_stack.remove(ix))
6821        } else if let Some(ix) = self
6822            .redo_stack
6823            .iter()
6824            .rposition(|transaction| transaction.id == transaction_id)
6825        {
6826            Some(self.redo_stack.remove(ix))
6827        } else {
6828            None
6829        }
6830    }
6831
6832    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6833        self.undo_stack
6834            .iter()
6835            .find(|transaction| transaction.id == transaction_id)
6836            .or_else(|| {
6837                self.redo_stack
6838                    .iter()
6839                    .find(|transaction| transaction.id == transaction_id)
6840            })
6841    }
6842
6843    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6844        self.undo_stack
6845            .iter_mut()
6846            .find(|transaction| transaction.id == transaction_id)
6847            .or_else(|| {
6848                self.redo_stack
6849                    .iter_mut()
6850                    .find(|transaction| transaction.id == transaction_id)
6851            })
6852    }
6853
6854    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6855        assert_eq!(self.transaction_depth, 0);
6856        if let Some(transaction) = self.undo_stack.pop() {
6857            self.redo_stack.push(transaction);
6858            self.redo_stack.last_mut()
6859        } else {
6860            None
6861        }
6862    }
6863
6864    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6865        assert_eq!(self.transaction_depth, 0);
6866        if let Some(transaction) = self.redo_stack.pop() {
6867            self.undo_stack.push(transaction);
6868            self.undo_stack.last_mut()
6869        } else {
6870            None
6871        }
6872    }
6873
6874    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6875        let ix = self
6876            .undo_stack
6877            .iter()
6878            .rposition(|transaction| transaction.id == transaction_id)?;
6879        let transaction = self.undo_stack.remove(ix);
6880        self.redo_stack.push(transaction);
6881        self.redo_stack.last()
6882    }
6883
6884    fn group(&mut self) -> Option<TransactionId> {
6885        let mut count = 0;
6886        let mut transactions = self.undo_stack.iter();
6887        if let Some(mut transaction) = transactions.next_back() {
6888            while let Some(prev_transaction) = transactions.next_back() {
6889                if !prev_transaction.suppress_grouping
6890                    && transaction.first_edit_at - prev_transaction.last_edit_at
6891                        <= self.group_interval
6892                {
6893                    transaction = prev_transaction;
6894                    count += 1;
6895                } else {
6896                    break;
6897                }
6898            }
6899        }
6900        self.group_trailing(count)
6901    }
6902
6903    fn group_until(&mut self, transaction_id: TransactionId) {
6904        let mut count = 0;
6905        for transaction in self.undo_stack.iter().rev() {
6906            if transaction.id == transaction_id {
6907                self.group_trailing(count);
6908                break;
6909            } else if transaction.suppress_grouping {
6910                break;
6911            } else {
6912                count += 1;
6913            }
6914        }
6915    }
6916
6917    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6918        let new_len = self.undo_stack.len() - n;
6919        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6920        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6921            if let Some(transaction) = transactions_to_merge.last() {
6922                last_transaction.last_edit_at = transaction.last_edit_at;
6923            }
6924            for to_merge in transactions_to_merge {
6925                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6926                    last_transaction
6927                        .buffer_transactions
6928                        .entry(*buffer_id)
6929                        .or_insert(*transaction_id);
6930                }
6931            }
6932        }
6933
6934        self.undo_stack.truncate(new_len);
6935        self.undo_stack.last().map(|t| t.id)
6936    }
6937}
6938
6939impl Excerpt {
6940    fn new(
6941        id: ExcerptId,
6942        locator: Locator,
6943        buffer_id: BufferId,
6944        buffer: BufferSnapshot,
6945        range: ExcerptRange<text::Anchor>,
6946        has_trailing_newline: bool,
6947    ) -> Self {
6948        Excerpt {
6949            id,
6950            locator,
6951            max_buffer_row: range.context.end.to_point(&buffer).row,
6952            text_summary: buffer
6953                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6954            buffer_id,
6955            buffer,
6956            range,
6957            has_trailing_newline,
6958        }
6959    }
6960
6961    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6962        let content_start = self.range.context.start.to_offset(&self.buffer);
6963        let chunks_start = content_start + range.start;
6964        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6965
6966        let footer_height = if self.has_trailing_newline
6967            && range.start <= self.text_summary.len
6968            && range.end > self.text_summary.len
6969        {
6970            1
6971        } else {
6972            0
6973        };
6974
6975        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6976
6977        ExcerptChunks {
6978            excerpt_id: self.id,
6979            content_chunks,
6980            footer_height,
6981        }
6982    }
6983
6984    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6985        let content_start = self.range.context.start.to_offset(&self.buffer);
6986        let chunks_start = content_start + range.start;
6987        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6988        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6989        excerpt_chunks.footer_height = if self.has_trailing_newline
6990            && range.start <= self.text_summary.len
6991            && range.end > self.text_summary.len
6992        {
6993            1
6994        } else {
6995            0
6996        };
6997    }
6998
6999    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7000        if text_anchor
7001            .cmp(&self.range.context.start, &self.buffer)
7002            .is_lt()
7003        {
7004            self.range.context.start
7005        } else if text_anchor
7006            .cmp(&self.range.context.end, &self.buffer)
7007            .is_gt()
7008        {
7009            self.range.context.end
7010        } else {
7011            text_anchor
7012        }
7013    }
7014
7015    fn contains(&self, anchor: &Anchor) -> bool {
7016        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
7017            && self
7018                .range
7019                .context
7020                .start
7021                .cmp(&anchor.text_anchor, &self.buffer)
7022                .is_le()
7023            && self
7024                .range
7025                .context
7026                .end
7027                .cmp(&anchor.text_anchor, &self.buffer)
7028                .is_ge()
7029    }
7030
7031    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7032    fn buffer_start_offset(&self) -> usize {
7033        self.range.context.start.to_offset(&self.buffer)
7034    }
7035
7036    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7037    fn buffer_end_offset(&self) -> usize {
7038        self.buffer_start_offset() + self.text_summary.len
7039    }
7040}
7041
7042impl<'a> MultiBufferExcerpt<'a> {
7043    pub fn id(&self) -> ExcerptId {
7044        self.excerpt.id
7045    }
7046
7047    pub fn buffer_id(&self) -> BufferId {
7048        self.excerpt.buffer_id
7049    }
7050
7051    pub fn start_anchor(&self) -> Anchor {
7052        Anchor::in_buffer(
7053            self.excerpt.id,
7054            self.excerpt.buffer_id,
7055            self.excerpt.range.context.start,
7056        )
7057    }
7058
7059    pub fn end_anchor(&self) -> Anchor {
7060        Anchor::in_buffer(
7061            self.excerpt.id,
7062            self.excerpt.buffer_id,
7063            self.excerpt.range.context.end,
7064        )
7065    }
7066
7067    pub fn buffer(&self) -> &'a BufferSnapshot {
7068        &self.excerpt.buffer
7069    }
7070
7071    pub fn buffer_range(&self) -> Range<usize> {
7072        self.buffer_offset
7073            ..self
7074                .excerpt
7075                .range
7076                .context
7077                .end
7078                .to_offset(&self.excerpt.buffer.text)
7079    }
7080
7081    pub fn start_offset(&self) -> usize {
7082        self.offset
7083    }
7084
7085    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7086    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
7087        self.map_range_to_buffer(offset..offset).start
7088    }
7089
7090    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7091    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
7092        self.diff_transforms
7093            .seek(&OutputDimension(range.start), Bias::Right);
7094        let start = self.map_offset_to_buffer_internal(range.start);
7095        let end = if range.end > range.start {
7096            self.diff_transforms
7097                .seek_forward(&OutputDimension(range.end), Bias::Right);
7098            self.map_offset_to_buffer_internal(range.end)
7099        } else {
7100            start
7101        };
7102        start..end
7103    }
7104
7105    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
7106        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
7107        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7108            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
7109        };
7110        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
7111        self.buffer_offset + offset_in_excerpt
7112    }
7113
7114    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7115    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
7116        self.map_range_from_buffer(buffer_offset..buffer_offset)
7117            .start
7118    }
7119
7120    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7121    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
7122        if buffer_range.start < self.buffer_offset {
7123            log::warn!(
7124                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7125            );
7126            return buffer_range;
7127        }
7128        let overshoot = buffer_range.start - self.buffer_offset;
7129        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7130        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
7131        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
7132            log::warn!(
7133                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7134            );
7135            return buffer_range;
7136        }
7137        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7138        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7139
7140        let end = if buffer_range.end > buffer_range.start {
7141            let overshoot = buffer_range.end - self.buffer_offset;
7142            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7143            self.diff_transforms
7144                .seek_forward(&excerpt_offset, Bias::Right);
7145            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7146            self.diff_transforms.start().output_dimension.0 + overshoot
7147        } else {
7148            start
7149        };
7150
7151        start..end
7152    }
7153
7154    /// Returns true if the entirety of the given range is in the buffer's excerpt
7155    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
7156        range.start >= self.excerpt.buffer_start_offset()
7157            && range.end <= self.excerpt.buffer_end_offset()
7158    }
7159
7160    pub fn max_buffer_row(&self) -> u32 {
7161        self.excerpt.max_buffer_row
7162    }
7163}
7164
7165impl ExcerptId {
7166    pub fn min() -> Self {
7167        Self(0)
7168    }
7169
7170    pub fn max() -> Self {
7171        Self(u32::MAX)
7172    }
7173
7174    pub fn to_proto(self) -> u64 {
7175        self.0 as _
7176    }
7177
7178    pub fn from_proto(proto: u64) -> Self {
7179        Self(proto as _)
7180    }
7181
7182    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7183        let a = snapshot.excerpt_locator_for_id(*self);
7184        let b = snapshot.excerpt_locator_for_id(*other);
7185        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7186    }
7187}
7188
7189impl From<ExcerptId> for usize {
7190    fn from(val: ExcerptId) -> Self {
7191        val.0 as usize
7192    }
7193}
7194
7195impl fmt::Debug for Excerpt {
7196    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7197        f.debug_struct("Excerpt")
7198            .field("id", &self.id)
7199            .field("locator", &self.locator)
7200            .field("buffer_id", &self.buffer_id)
7201            .field("range", &self.range)
7202            .field("text_summary", &self.text_summary)
7203            .field("has_trailing_newline", &self.has_trailing_newline)
7204            .finish()
7205    }
7206}
7207
7208impl sum_tree::Item for Excerpt {
7209    type Summary = ExcerptSummary;
7210
7211    fn summary(&self, _cx: ()) -> Self::Summary {
7212        let mut text = self.text_summary;
7213        if self.has_trailing_newline {
7214            text += TextSummary::from("\n");
7215        }
7216        ExcerptSummary {
7217            excerpt_id: self.id,
7218            excerpt_locator: self.locator.clone(),
7219            widest_line_number: self.max_buffer_row,
7220            text,
7221        }
7222    }
7223}
7224
7225impl sum_tree::Item for ExcerptIdMapping {
7226    type Summary = ExcerptId;
7227
7228    fn summary(&self, _cx: ()) -> Self::Summary {
7229        self.id
7230    }
7231}
7232
7233impl sum_tree::KeyedItem for ExcerptIdMapping {
7234    type Key = ExcerptId;
7235
7236    fn key(&self) -> Self::Key {
7237        self.id
7238    }
7239}
7240
7241impl DiffTransform {
7242    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7243        match self {
7244            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7245            DiffTransform::BufferContent {
7246                inserted_hunk_info, ..
7247            } => *inserted_hunk_info,
7248        }
7249    }
7250}
7251
7252impl sum_tree::Item for DiffTransform {
7253    type Summary = DiffTransformSummary;
7254
7255    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7256        match self {
7257            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7258                input: *summary,
7259                output: *summary,
7260            },
7261            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7262                input: TextSummary::default(),
7263                output: *summary,
7264            },
7265        }
7266    }
7267}
7268
7269impl DiffTransformSummary {
7270    fn excerpt_len(&self) -> ExcerptOffset {
7271        ExcerptOffset::new(self.input.len)
7272    }
7273}
7274
7275impl sum_tree::ContextLessSummary for DiffTransformSummary {
7276    fn zero() -> Self {
7277        DiffTransformSummary {
7278            input: TextSummary::default(),
7279            output: TextSummary::default(),
7280        }
7281    }
7282
7283    fn add_summary(&mut self, other: &Self) {
7284        self.input += other.input;
7285        self.output += other.output;
7286    }
7287}
7288
7289impl sum_tree::ContextLessSummary for ExcerptId {
7290    fn zero() -> Self {
7291        Self(0)
7292    }
7293
7294    fn add_summary(&mut self, summary: &Self) {
7295        *self = cmp::max(*self, *summary);
7296    }
7297}
7298
7299impl sum_tree::ContextLessSummary for ExcerptSummary {
7300    fn zero() -> Self {
7301        Self::default()
7302    }
7303
7304    fn add_summary(&mut self, summary: &Self) {
7305        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7306        self.excerpt_locator = summary.excerpt_locator.clone();
7307        Summary::add_summary(&mut self.text, &summary.text, ());
7308        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7309    }
7310}
7311
7312impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7313    fn zero(_cx: ()) -> Self {
7314        Default::default()
7315    }
7316
7317    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7318        self.value += summary.text.len;
7319    }
7320}
7321
7322impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7323    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7324        Ord::cmp(&self.value, &cursor_location.text.len)
7325    }
7326}
7327
7328impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7329    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7330        Ord::cmp(&Some(self), cursor_location)
7331    }
7332}
7333
7334impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7335    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7336        Ord::cmp(self, &cursor_location.excerpt_locator)
7337    }
7338}
7339
7340impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7341    fn zero(_cx: ()) -> Self {
7342        Default::default()
7343    }
7344
7345    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7346        self.value += summary.text.lines;
7347    }
7348}
7349
7350impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7351    for ExcerptDimension<D>
7352{
7353    fn zero(_: ()) -> Self {
7354        ExcerptDimension(D::default())
7355    }
7356
7357    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7358        self.0.add_assign(&D::from_text_summary(&summary.text))
7359    }
7360}
7361
7362impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7363    fn zero(_cx: ()) -> Self {
7364        Default::default()
7365    }
7366
7367    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7368        *self = Some(&summary.excerpt_locator);
7369    }
7370}
7371
7372impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7373    fn zero(_cx: ()) -> Self {
7374        Default::default()
7375    }
7376
7377    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7378        *self = Some(summary.excerpt_id);
7379    }
7380}
7381
7382#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7383struct ExcerptDimension<T>(T);
7384
7385#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7386struct OutputDimension<T>(T);
7387
7388impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7389    fn zero(_: ()) -> Self {
7390        ExcerptOffset::new(0)
7391    }
7392
7393    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7394        self.value += summary.input.len;
7395    }
7396}
7397
7398impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7399    fn zero(_: ()) -> Self {
7400        ExcerptPoint::new(0, 0)
7401    }
7402
7403    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7404        self.value += summary.input.lines;
7405    }
7406}
7407
7408impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7409    for ExcerptDimension<D>
7410{
7411    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7412        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7413    }
7414}
7415
7416impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7417    for ExcerptDimension<D>
7418{
7419    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
7420        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7421    }
7422}
7423
7424impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7425    fn zero(_: ()) -> Self {
7426        ExcerptDimension(D::default())
7427    }
7428
7429    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7430        self.0.add_assign(&D::from_text_summary(&summary.input))
7431    }
7432}
7433
7434impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7435    for OutputDimension<D>
7436{
7437    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
7438        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7439    }
7440}
7441
7442impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7443    fn zero(_: ()) -> Self {
7444        OutputDimension(D::default())
7445    }
7446
7447    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7448        self.0.add_assign(&D::from_text_summary(&summary.output))
7449    }
7450}
7451
7452impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7453    fn zero(_: ()) -> Self {
7454        TextSummary::default()
7455    }
7456
7457    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7458        *self += summary.output
7459    }
7460}
7461
7462impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7463    fn zero(_: ()) -> Self {
7464        0
7465    }
7466
7467    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7468        *self += summary.output.len
7469    }
7470}
7471
7472impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7473    fn zero(_: ()) -> Self {
7474        Point::new(0, 0)
7475    }
7476
7477    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7478        *self += summary.output.lines
7479    }
7480}
7481
7482impl MultiBufferRows<'_> {
7483    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7484        self.point = Point::new(row, 0);
7485        self.cursor.seek(&self.point);
7486    }
7487}
7488
7489impl Iterator for MultiBufferRows<'_> {
7490    type Item = RowInfo;
7491
7492    fn next(&mut self) -> Option<Self::Item> {
7493        if self.is_empty && self.point.row == 0 {
7494            self.point += Point::new(1, 0);
7495            return Some(RowInfo {
7496                buffer_id: None,
7497                buffer_row: Some(0),
7498                multibuffer_row: Some(MultiBufferRow(0)),
7499                diff_status: None,
7500                expand_info: None,
7501                wrapped: None,
7502            });
7503        }
7504
7505        let mut region = self.cursor.region()?;
7506        while self.point >= region.range.end {
7507            self.cursor.next();
7508            if let Some(next_region) = self.cursor.region() {
7509                region = next_region;
7510            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7511                let multibuffer_row = MultiBufferRow(self.point.row);
7512                let last_excerpt = self
7513                    .cursor
7514                    .excerpts
7515                    .item()
7516                    .or(self.cursor.excerpts.prev_item())?;
7517                let last_row = last_excerpt
7518                    .range
7519                    .context
7520                    .end
7521                    .to_point(&last_excerpt.buffer)
7522                    .row;
7523
7524                let first_row = last_excerpt
7525                    .range
7526                    .context
7527                    .start
7528                    .to_point(&last_excerpt.buffer)
7529                    .row;
7530
7531                let expand_info = if self.is_singleton {
7532                    None
7533                } else {
7534                    let needs_expand_up = first_row == last_row
7535                        && last_row > 0
7536                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7537                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7538
7539                    if needs_expand_up && needs_expand_down {
7540                        Some(ExpandExcerptDirection::UpAndDown)
7541                    } else if needs_expand_up {
7542                        Some(ExpandExcerptDirection::Up)
7543                    } else if needs_expand_down {
7544                        Some(ExpandExcerptDirection::Down)
7545                    } else {
7546                        None
7547                    }
7548                    .map(|direction| ExpandInfo {
7549                        direction,
7550                        excerpt_id: last_excerpt.id,
7551                    })
7552                };
7553                self.point += Point::new(1, 0);
7554                return Some(RowInfo {
7555                    buffer_id: Some(last_excerpt.buffer_id),
7556                    buffer_row: Some(last_row),
7557                    multibuffer_row: Some(multibuffer_row),
7558                    diff_status: None,
7559                    wrapped: None,
7560                    expand_info,
7561                });
7562            } else {
7563                return None;
7564            };
7565        }
7566
7567        let overshoot = self.point - region.range.start;
7568        let buffer_point = region.buffer_range.start + overshoot;
7569        let expand_info = if self.is_singleton {
7570            None
7571        } else {
7572            let needs_expand_up = self.point.row == region.range.start.row
7573                && self.cursor.is_at_start_of_excerpt()
7574                && buffer_point.row > 0;
7575            let needs_expand_down = (region.excerpt.has_trailing_newline
7576                && self.point.row + 1 == region.range.end.row
7577                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7578                && self.cursor.is_at_end_of_excerpt()
7579                && buffer_point.row < region.buffer.max_point().row;
7580
7581            if needs_expand_up && needs_expand_down {
7582                Some(ExpandExcerptDirection::UpAndDown)
7583            } else if needs_expand_up {
7584                Some(ExpandExcerptDirection::Up)
7585            } else if needs_expand_down {
7586                Some(ExpandExcerptDirection::Down)
7587            } else {
7588                None
7589            }
7590            .map(|direction| ExpandInfo {
7591                direction,
7592                excerpt_id: region.excerpt.id,
7593            })
7594        };
7595
7596        let result = Some(RowInfo {
7597            buffer_id: Some(region.buffer.remote_id()),
7598            buffer_row: Some(buffer_point.row),
7599            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7600            diff_status: region
7601                .diff_hunk_status
7602                .filter(|_| self.point < region.range.end),
7603            expand_info,
7604            wrapped: None,
7605        });
7606        self.point += Point::new(1, 0);
7607        result
7608    }
7609}
7610
7611impl<'a> MultiBufferChunks<'a> {
7612    pub fn offset(&self) -> usize {
7613        self.range.start
7614    }
7615
7616    pub fn seek(&mut self, range: Range<usize>) {
7617        self.diff_transforms.seek(&range.end, Bias::Right);
7618        let mut excerpt_end = self.diff_transforms.start().1;
7619        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7620            let overshoot = range.end - self.diff_transforms.start().0;
7621            excerpt_end.value += overshoot;
7622        }
7623
7624        self.diff_transforms.seek(&range.start, Bias::Right);
7625        let mut excerpt_start = self.diff_transforms.start().1;
7626        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7627            let overshoot = range.start - self.diff_transforms.start().0;
7628            excerpt_start.value += overshoot;
7629        }
7630
7631        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7632        self.buffer_chunk.take();
7633        self.range = range;
7634    }
7635
7636    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7637        self.excerpt_offset_range = new_range.clone();
7638        self.excerpts.seek(&new_range.start, Bias::Right);
7639        if let Some(excerpt) = self.excerpts.item() {
7640            let excerpt_start = *self.excerpts.start();
7641            if let Some(excerpt_chunks) = self
7642                .excerpt_chunks
7643                .as_mut()
7644                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7645            {
7646                excerpt.seek_chunks(
7647                    excerpt_chunks,
7648                    (self.excerpt_offset_range.start - excerpt_start).value
7649                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7650                );
7651            } else {
7652                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7653                    (self.excerpt_offset_range.start - excerpt_start).value
7654                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7655                    self.language_aware,
7656                ));
7657            }
7658        } else {
7659            self.excerpt_chunks = None;
7660        }
7661    }
7662
7663    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7664        loop {
7665            if self.excerpt_offset_range.is_empty() {
7666                return None;
7667            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7668                self.excerpt_offset_range.start.value += chunk.text.len();
7669                return Some(chunk);
7670            } else {
7671                self.excerpts.next();
7672                let excerpt = self.excerpts.item()?;
7673                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7674                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7675                    self.language_aware,
7676                ));
7677            }
7678        }
7679    }
7680}
7681
7682impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7683    type Item = &'a str;
7684
7685    fn next(&mut self) -> Option<Self::Item> {
7686        let mut region = self.cursor.region()?;
7687        if self.offset == region.range.start {
7688            self.cursor.prev();
7689            region = self.cursor.region()?;
7690            let start_overshoot = self.start.saturating_sub(region.range.start);
7691            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7692                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7693            ));
7694        }
7695
7696        if self.offset == region.range.end && region.has_trailing_newline {
7697            self.offset -= 1;
7698            Some("\n")
7699        } else {
7700            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7701            self.offset -= chunk.len();
7702            Some(chunk)
7703        }
7704    }
7705}
7706
7707impl<'a> Iterator for MultiBufferChunks<'a> {
7708    type Item = Chunk<'a>;
7709
7710    fn next(&mut self) -> Option<Chunk<'a>> {
7711        if self.range.start >= self.range.end {
7712            return None;
7713        }
7714        if self.range.start == self.diff_transforms.end().0 {
7715            self.diff_transforms.next();
7716        }
7717
7718        let diff_transform_start = self.diff_transforms.start().0;
7719        let diff_transform_end = self.diff_transforms.end().0;
7720        debug_assert!(self.range.start < diff_transform_end);
7721
7722        let diff_transform = self.diff_transforms.item()?;
7723        match diff_transform {
7724            DiffTransform::BufferContent { .. } => {
7725                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7726                    chunk
7727                } else {
7728                    let chunk = self.next_excerpt_chunk().unwrap();
7729                    self.buffer_chunk.insert(chunk)
7730                };
7731
7732                let chunk_end = self.range.start + chunk.text.len();
7733                let diff_transform_end = diff_transform_end.min(self.range.end);
7734
7735                if diff_transform_end < chunk_end {
7736                    let split_idx = diff_transform_end - self.range.start;
7737                    let (before, after) = chunk.text.split_at(split_idx);
7738                    self.range.start = diff_transform_end;
7739                    let mask = (1 << split_idx) - 1;
7740                    let chars = chunk.chars & mask;
7741                    let tabs = chunk.tabs & mask;
7742
7743                    chunk.text = after;
7744                    chunk.chars = chunk.chars >> split_idx;
7745                    chunk.tabs = chunk.tabs >> split_idx;
7746
7747                    Some(Chunk {
7748                        text: before,
7749                        chars,
7750                        tabs,
7751                        ..chunk.clone()
7752                    })
7753                } else {
7754                    self.range.start = chunk_end;
7755                    self.buffer_chunk.take()
7756                }
7757            }
7758            DiffTransform::DeletedHunk {
7759                buffer_id,
7760                base_text_byte_range,
7761                has_trailing_newline,
7762                ..
7763            } => {
7764                let base_text_start =
7765                    base_text_byte_range.start + self.range.start - diff_transform_start;
7766                let base_text_end =
7767                    base_text_byte_range.start + self.range.end - diff_transform_start;
7768                let base_text_end = base_text_end.min(base_text_byte_range.end);
7769
7770                let mut chunks = if let Some((_, mut chunks)) = self
7771                    .diff_base_chunks
7772                    .take()
7773                    .filter(|(id, _)| id == buffer_id)
7774                {
7775                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7776                    {
7777                        chunks.seek(base_text_start..base_text_end);
7778                    }
7779                    chunks
7780                } else {
7781                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7782                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7783                };
7784
7785                let chunk = if let Some(chunk) = chunks.next() {
7786                    self.range.start += chunk.text.len();
7787                    self.diff_base_chunks = Some((*buffer_id, chunks));
7788                    chunk
7789                } else {
7790                    debug_assert!(has_trailing_newline);
7791                    self.range.start += "\n".len();
7792                    Chunk {
7793                        text: "\n",
7794                        chars: 1u128,
7795                        ..Default::default()
7796                    }
7797                };
7798                Some(chunk)
7799            }
7800        }
7801    }
7802}
7803
7804impl MultiBufferBytes<'_> {
7805    fn consume(&mut self, len: usize) {
7806        self.range.start += len;
7807        self.chunk = &self.chunk[len..];
7808
7809        if !self.range.is_empty() && self.chunk.is_empty() {
7810            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7811                self.chunk = chunk;
7812            } else if self.has_trailing_newline {
7813                self.has_trailing_newline = false;
7814                self.chunk = b"\n";
7815            } else {
7816                self.cursor.next();
7817                if let Some(region) = self.cursor.region() {
7818                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7819                        region.buffer_range.start
7820                            ..(region.buffer_range.start + self.range.end - region.range.start)
7821                                .min(region.buffer_range.end),
7822                    );
7823                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7824                    self.excerpt_bytes = Some(excerpt_bytes);
7825                    self.has_trailing_newline =
7826                        region.has_trailing_newline && self.range.end >= region.range.end;
7827                    if self.chunk.is_empty() && self.has_trailing_newline {
7828                        self.has_trailing_newline = false;
7829                        self.chunk = b"\n";
7830                    }
7831                }
7832            }
7833        }
7834    }
7835}
7836
7837impl<'a> Iterator for MultiBufferBytes<'a> {
7838    type Item = &'a [u8];
7839
7840    fn next(&mut self) -> Option<Self::Item> {
7841        let chunk = self.chunk;
7842        if chunk.is_empty() {
7843            None
7844        } else {
7845            self.consume(chunk.len());
7846            Some(chunk)
7847        }
7848    }
7849}
7850
7851impl io::Read for MultiBufferBytes<'_> {
7852    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7853        let len = cmp::min(buf.len(), self.chunk.len());
7854        buf[..len].copy_from_slice(&self.chunk[..len]);
7855        if len > 0 {
7856            self.consume(len);
7857        }
7858        Ok(len)
7859    }
7860}
7861
7862impl io::Read for ReversedMultiBufferBytes<'_> {
7863    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7864        let len = cmp::min(buf.len(), self.chunk.len());
7865        buf[..len].copy_from_slice(&self.chunk[..len]);
7866        buf[..len].reverse();
7867        if len > 0 {
7868            self.range.end -= len;
7869            self.chunk = &self.chunk[..self.chunk.len() - len];
7870            if !self.range.is_empty()
7871                && self.chunk.is_empty()
7872                && let Some(chunk) = self.chunks.next()
7873            {
7874                self.chunk = chunk.as_bytes();
7875            }
7876        }
7877        Ok(len)
7878    }
7879}
7880
7881impl<'a> Iterator for ExcerptChunks<'a> {
7882    type Item = Chunk<'a>;
7883
7884    fn next(&mut self) -> Option<Self::Item> {
7885        if let Some(chunk) = self.content_chunks.next() {
7886            return Some(chunk);
7887        }
7888
7889        if self.footer_height > 0 {
7890            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7891            let chars = (1 << self.footer_height) - 1;
7892            self.footer_height = 0;
7893            return Some(Chunk {
7894                text,
7895                chars,
7896                ..Default::default()
7897            });
7898        }
7899
7900        None
7901    }
7902}
7903
7904impl ToOffset for Point {
7905    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7906        snapshot.point_to_offset(*self)
7907    }
7908}
7909
7910impl ToOffset for usize {
7911    #[track_caller]
7912    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7913        assert!(
7914            *self <= snapshot.len(),
7915            "offset {} is greater than the snapshot.len() {}",
7916            *self,
7917            snapshot.len(),
7918        );
7919        *self
7920    }
7921}
7922
7923impl ToOffset for OffsetUtf16 {
7924    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7925        snapshot.offset_utf16_to_offset(*self)
7926    }
7927}
7928
7929impl ToOffset for PointUtf16 {
7930    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7931        snapshot.point_utf16_to_offset(*self)
7932    }
7933}
7934
7935impl ToOffsetUtf16 for OffsetUtf16 {
7936    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7937        *self
7938    }
7939}
7940
7941impl ToOffsetUtf16 for usize {
7942    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7943        snapshot.offset_to_offset_utf16(*self)
7944    }
7945}
7946
7947impl ToPoint for usize {
7948    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7949        snapshot.offset_to_point(*self)
7950    }
7951}
7952
7953impl ToPoint for Point {
7954    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7955        *self
7956    }
7957}
7958
7959impl ToPointUtf16 for usize {
7960    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7961        snapshot.offset_to_point_utf16(*self)
7962    }
7963}
7964
7965impl ToPointUtf16 for Point {
7966    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7967        snapshot.point_to_point_utf16(*self)
7968    }
7969}
7970
7971impl ToPointUtf16 for PointUtf16 {
7972    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7973        *self
7974    }
7975}
7976
7977impl From<ExcerptId> for EntityId {
7978    fn from(id: ExcerptId) -> Self {
7979        EntityId::from(id.0 as u64)
7980    }
7981}
7982
7983#[cfg(debug_assertions)]
7984pub mod debug {
7985    use super::*;
7986
7987    pub trait ToMultiBufferDebugRanges {
7988        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
7989        -> Vec<Range<usize>>;
7990    }
7991
7992    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7993        fn to_multi_buffer_debug_ranges(
7994            &self,
7995            snapshot: &MultiBufferSnapshot,
7996        ) -> Vec<Range<usize>> {
7997            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7998        }
7999    }
8000
8001    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8002        fn to_multi_buffer_debug_ranges(
8003            &self,
8004            snapshot: &MultiBufferSnapshot,
8005        ) -> Vec<Range<usize>> {
8006            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8007                .to_multi_buffer_debug_ranges(snapshot)
8008        }
8009    }
8010
8011    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8012        fn to_multi_buffer_debug_ranges(
8013            &self,
8014            snapshot: &MultiBufferSnapshot,
8015        ) -> Vec<Range<usize>> {
8016            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8017        }
8018    }
8019
8020    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8021        fn to_multi_buffer_debug_ranges(
8022            &self,
8023            snapshot: &MultiBufferSnapshot,
8024        ) -> Vec<Range<usize>> {
8025            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8026        }
8027    }
8028
8029    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8030        fn to_multi_buffer_debug_ranges(
8031            &self,
8032            snapshot: &MultiBufferSnapshot,
8033        ) -> Vec<Range<usize>> {
8034            self.iter()
8035                .map(|item| {
8036                    let offset = item.to_offset(snapshot);
8037                    offset..offset
8038                })
8039                .collect()
8040        }
8041    }
8042
8043    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8044        fn to_multi_buffer_debug_ranges(
8045            &self,
8046            snapshot: &MultiBufferSnapshot,
8047        ) -> Vec<Range<usize>> {
8048            self.iter()
8049                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8050                .collect()
8051        }
8052    }
8053}