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