1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod position;
   6mod transaction;
   7
   8use self::transaction::History;
   9
  10pub use anchor::{Anchor, AnchorRangeExt, Offset};
  11pub use position::{TypedOffset, TypedPoint, TypedRow};
  12
  13use anyhow::{Result, anyhow};
  14use buffer_diff::{
  15    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  16    DiffHunkStatusKind,
  17};
  18use clock::ReplicaId;
  19use collections::{BTreeMap, Bound, HashMap, HashSet};
  20use gpui::{App, Context, Entity, EntityId, EventEmitter};
  21use itertools::Itertools;
  22use language::{
  23    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  24    CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState, File,
  25    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  26    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  27    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  28    language_settings::{LanguageSettings, language_settings},
  29};
  30
  31#[cfg(any(test, feature = "test-support"))]
  32use gpui::AppContext as _;
  33
  34use rope::DimensionPair;
  35use smallvec::SmallVec;
  36use smol::future::yield_now;
  37use std::{
  38    any::type_name,
  39    borrow::Cow,
  40    cell::{Cell, Ref, RefCell},
  41    cmp, fmt,
  42    future::Future,
  43    io,
  44    iter::{self, FromIterator},
  45    mem,
  46    ops::{Range, RangeBounds, Sub},
  47    rc::Rc,
  48    str,
  49    sync::Arc,
  50    time::Duration,
  51};
  52use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, Summary, TreeMap};
  53use text::{
  54    BufferId, Edit, LineIndent, TextSummary,
  55    locator::Locator,
  56    subscription::{Subscription, Topic},
  57};
  58use theme::SyntaxTheme;
  59use util::post_inc;
  60
  61pub use self::path_key::PathKey;
  62
  63#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  64pub struct ExcerptId(u32);
  65
  66/// One or more [`Buffers`](Buffer) being edited in a single view.
  67///
  68/// See <https://zed.dev/features#multi-buffers>
  69pub struct MultiBuffer {
  70    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  71    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  72    snapshot: RefCell<MultiBufferSnapshot>,
  73    /// Contains the state of the buffers being edited
  74    buffers: HashMap<BufferId, BufferState>,
  75    /// Mapping from path keys to their excerpts.
  76    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  77    /// Mapping from excerpt IDs to their path key.
  78    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  79    /// Mapping from buffer IDs to their diff states
  80    diffs: HashMap<BufferId, DiffState>,
  81    subscriptions: Topic,
  82    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  83    singleton: bool,
  84    /// The history of the multi-buffer.
  85    history: History,
  86    /// The explicit title of the multi-buffer.
  87    /// If `None`, it will be derived from the underlying path or content.
  88    title: Option<String>,
  89    /// The writing capability of the multi-buffer.
  90    capability: Capability,
  91    buffer_changed_since_sync: Rc<Cell<bool>>,
  92}
  93
  94#[derive(Clone, Debug, PartialEq, Eq)]
  95pub enum Event {
  96    ExcerptsAdded {
  97        buffer: Entity<Buffer>,
  98        predecessor: ExcerptId,
  99        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 100    },
 101    ExcerptsRemoved {
 102        ids: Vec<ExcerptId>,
 103        removed_buffer_ids: Vec<BufferId>,
 104    },
 105    ExcerptsExpanded {
 106        ids: Vec<ExcerptId>,
 107    },
 108    ExcerptsEdited {
 109        excerpt_ids: Vec<ExcerptId>,
 110        buffer_ids: Vec<BufferId>,
 111    },
 112    DiffHunksToggled,
 113    Edited {
 114        edited_buffer: Option<Entity<Buffer>>,
 115    },
 116    TransactionUndone {
 117        transaction_id: TransactionId,
 118    },
 119    Reloaded,
 120    LanguageChanged(BufferId),
 121    Reparsed(BufferId),
 122    Saved,
 123    FileHandleChanged,
 124    DirtyChanged,
 125    DiagnosticsUpdated,
 126    BufferDiffChanged,
 127}
 128
 129/// A diff hunk, representing a range of consequent lines in a multibuffer.
 130#[derive(Debug, Clone, PartialEq, Eq)]
 131pub struct MultiBufferDiffHunk {
 132    /// The row range in the multibuffer where this diff hunk appears.
 133    pub row_range: Range<MultiBufferRow>,
 134    /// The buffer ID that this hunk belongs to.
 135    pub buffer_id: BufferId,
 136    /// The range of the underlying buffer that this hunk corresponds to.
 137    pub buffer_range: Range<text::Anchor>,
 138    /// The excerpt that contains the diff hunk.
 139    pub excerpt_id: ExcerptId,
 140    /// The range within the buffer's diff base that this hunk corresponds to.
 141    pub diff_base_byte_range: Range<usize>,
 142    /// Whether or not this hunk also appears in the 'secondary diff'.
 143    pub secondary_status: DiffHunkSecondaryStatus,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (0..0)
 163            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 164    }
 165
 166    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 167        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 168        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 169        start..end
 170    }
 171}
 172
 173pub type MultiBufferPoint = Point;
 174type ExcerptOffset = TypedOffset<Excerpt>;
 175type ExcerptPoint = TypedPoint<Excerpt>;
 176
 177#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 178#[serde(transparent)]
 179pub struct MultiBufferRow(pub u32);
 180
 181impl MultiBufferRow {
 182    pub const MIN: Self = Self(0);
 183    pub const MAX: Self = Self(u32::MAX);
 184}
 185
 186impl std::ops::Add<usize> for MultiBufferRow {
 187    type Output = Self;
 188
 189    fn add(self, rhs: usize) -> Self::Output {
 190        MultiBufferRow(self.0 + rhs as u32)
 191    }
 192}
 193
 194pub trait ToOffset: 'static + fmt::Debug {
 195    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 196    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 197}
 198
 199pub trait ToPoint: 'static + fmt::Debug {
 200    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 201    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 202}
 203
 204struct BufferState {
 205    buffer: Entity<Buffer>,
 206    last_version: RefCell<clock::Global>,
 207    last_non_text_state_update_count: Cell<usize>,
 208    excerpts: Vec<Locator>,
 209    _subscriptions: [gpui::Subscription; 2],
 210}
 211
 212struct DiffState {
 213    diff: Entity<BufferDiff>,
 214    _subscription: gpui::Subscription,
 215}
 216
 217impl DiffState {
 218    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 219        DiffState {
 220            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 221                BufferDiffEvent::DiffChanged { changed_range } => {
 222                    if let Some(changed_range) = changed_range.clone() {
 223                        this.buffer_diff_changed(diff, changed_range, cx)
 224                    }
 225                    cx.emit(Event::BufferDiffChanged);
 226                }
 227                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 228                _ => {}
 229            }),
 230            diff,
 231        }
 232    }
 233}
 234
 235/// The contents of a [`MultiBuffer`] at a single point in time.
 236#[derive(Clone, Default)]
 237pub struct MultiBufferSnapshot {
 238    excerpts: SumTree<Excerpt>,
 239    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 240    diff_transforms: SumTree<DiffTransform>,
 241    non_text_state_update_count: usize,
 242    edit_count: usize,
 243    is_dirty: bool,
 244    has_deleted_file: bool,
 245    has_conflict: bool,
 246    /// immutable fields
 247    singleton: bool,
 248    excerpt_ids: SumTree<ExcerptIdMapping>,
 249    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 250    trailing_excerpt_update_count: usize,
 251    all_diff_hunks_expanded: bool,
 252    show_headers: bool,
 253}
 254
 255#[derive(Debug, Clone)]
 256enum DiffTransform {
 257    BufferContent {
 258        summary: TextSummary,
 259        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 260    },
 261    DeletedHunk {
 262        summary: TextSummary,
 263        buffer_id: BufferId,
 264        hunk_info: DiffTransformHunkInfo,
 265        base_text_byte_range: Range<usize>,
 266        has_trailing_newline: bool,
 267    },
 268}
 269
 270#[derive(Clone, Copy, Debug)]
 271struct DiffTransformHunkInfo {
 272    excerpt_id: ExcerptId,
 273    hunk_start_anchor: text::Anchor,
 274    hunk_secondary_status: DiffHunkSecondaryStatus,
 275}
 276
 277impl Eq for DiffTransformHunkInfo {}
 278
 279impl PartialEq for DiffTransformHunkInfo {
 280    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 281        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 282    }
 283}
 284
 285impl std::hash::Hash for DiffTransformHunkInfo {
 286    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 287        self.excerpt_id.hash(state);
 288        self.hunk_start_anchor.hash(state);
 289    }
 290}
 291
 292#[derive(Clone)]
 293pub struct ExcerptInfo {
 294    pub id: ExcerptId,
 295    pub buffer: BufferSnapshot,
 296    pub buffer_id: BufferId,
 297    pub range: ExcerptRange<text::Anchor>,
 298    pub end_row: MultiBufferRow,
 299}
 300
 301impl std::fmt::Debug for ExcerptInfo {
 302    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 303        f.debug_struct(type_name::<Self>())
 304            .field("id", &self.id)
 305            .field("buffer_id", &self.buffer_id)
 306            .field("path", &self.buffer.file().map(|f| f.path()))
 307            .field("range", &self.range)
 308            .finish()
 309    }
 310}
 311
 312/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 313#[derive(Debug)]
 314pub struct ExcerptBoundary {
 315    pub prev: Option<ExcerptInfo>,
 316    pub next: ExcerptInfo,
 317    /// The row in the `MultiBuffer` where the boundary is located
 318    pub row: MultiBufferRow,
 319}
 320
 321impl ExcerptBoundary {
 322    pub fn starts_new_buffer(&self) -> bool {
 323        match (self.prev.as_ref(), &self.next) {
 324            (None, _) => true,
 325            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 326        }
 327    }
 328}
 329
 330#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 331pub struct ExpandInfo {
 332    pub direction: ExpandExcerptDirection,
 333    pub excerpt_id: ExcerptId,
 334}
 335
 336#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 337pub struct RowInfo {
 338    pub buffer_id: Option<BufferId>,
 339    pub buffer_row: Option<u32>,
 340    pub multibuffer_row: Option<MultiBufferRow>,
 341    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 342    pub expand_info: Option<ExpandInfo>,
 343    pub wrapped_buffer_row: Option<u32>,
 344}
 345
 346/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 347#[derive(Clone)]
 348struct Excerpt {
 349    /// The unique identifier for this excerpt
 350    id: ExcerptId,
 351    /// The location of the excerpt in the [`MultiBuffer`]
 352    locator: Locator,
 353    /// The buffer being excerpted
 354    buffer_id: BufferId,
 355    /// A snapshot of the buffer being excerpted
 356    buffer: BufferSnapshot,
 357    /// The range of the buffer to be shown in the excerpt
 358    range: ExcerptRange<text::Anchor>,
 359    /// The last row in the excerpted slice of the buffer
 360    max_buffer_row: BufferRow,
 361    /// A summary of the text in the excerpt
 362    text_summary: TextSummary,
 363    has_trailing_newline: bool,
 364}
 365
 366/// A public view into an `Excerpt` in a [`MultiBuffer`].
 367///
 368/// Contains methods for getting the [`Buffer`] of the excerpt,
 369/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 370#[derive(Clone)]
 371pub struct MultiBufferExcerpt<'a> {
 372    excerpt: &'a Excerpt,
 373    diff_transforms: sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<usize>>,
 374    offset: usize,
 375    excerpt_offset: ExcerptDimension<usize>,
 376    buffer_offset: usize,
 377}
 378
 379#[derive(Clone, Debug)]
 380struct ExcerptIdMapping {
 381    id: ExcerptId,
 382    locator: Locator,
 383}
 384
 385/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 386/// These ranges are relative to the buffer itself
 387#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 388pub struct ExcerptRange<T> {
 389    /// The full range of text to be shown in the excerpt.
 390    pub context: Range<T>,
 391    /// The primary range of text to be highlighted in the excerpt.
 392    /// In a multi-buffer search, this would be the text that matched the search
 393    pub primary: Range<T>,
 394}
 395
 396impl<T: Clone> ExcerptRange<T> {
 397    pub fn new(context: Range<T>) -> Self {
 398        Self {
 399            context: context.clone(),
 400            primary: context,
 401        }
 402    }
 403}
 404
 405#[derive(Clone, Debug, Default)]
 406pub struct ExcerptSummary {
 407    excerpt_id: ExcerptId,
 408    /// The location of the last [`Excerpt`] being summarized
 409    excerpt_locator: Locator,
 410    widest_line_number: u32,
 411    text: TextSummary,
 412}
 413
 414#[derive(Debug, Clone)]
 415pub struct DiffTransformSummary {
 416    input: TextSummary,
 417    output: TextSummary,
 418}
 419
 420#[derive(Clone)]
 421pub struct MultiBufferRows<'a> {
 422    point: Point,
 423    is_empty: bool,
 424    is_singleton: bool,
 425    cursor: MultiBufferCursor<'a, Point>,
 426}
 427
 428pub struct MultiBufferChunks<'a> {
 429    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 430    diff_transforms: Cursor<'a, 'static, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 431    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 432    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 433    buffer_chunk: Option<Chunk<'a>>,
 434    range: Range<usize>,
 435    excerpt_offset_range: Range<ExcerptOffset>,
 436    excerpt_chunks: Option<ExcerptChunks<'a>>,
 437    language_aware: bool,
 438}
 439
 440pub struct ReversedMultiBufferChunks<'a> {
 441    cursor: MultiBufferCursor<'a, usize>,
 442    current_chunks: Option<rope::Chunks<'a>>,
 443    start: usize,
 444    offset: usize,
 445}
 446
 447pub struct MultiBufferBytes<'a> {
 448    range: Range<usize>,
 449    cursor: MultiBufferCursor<'a, usize>,
 450    excerpt_bytes: Option<text::Bytes<'a>>,
 451    has_trailing_newline: bool,
 452    chunk: &'a [u8],
 453}
 454
 455pub struct ReversedMultiBufferBytes<'a> {
 456    range: Range<usize>,
 457    chunks: ReversedMultiBufferChunks<'a>,
 458    chunk: &'a [u8],
 459}
 460
 461#[derive(Clone)]
 462struct DiffTransforms<D> {
 463    output_dimension: OutputDimension<D>,
 464    excerpt_dimension: ExcerptDimension<D>,
 465}
 466
 467impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 468    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 469        Self {
 470            output_dimension: OutputDimension::zero(cx),
 471            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 472                cx,
 473            ),
 474        }
 475    }
 476
 477    fn add_summary(
 478        &mut self,
 479        summary: &'a DiffTransformSummary,
 480        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 481    ) {
 482        self.output_dimension.add_summary(summary, cx);
 483        self.excerpt_dimension.add_summary(summary, cx);
 484    }
 485}
 486
 487#[derive(Clone)]
 488struct MultiBufferCursor<'a, D: TextDimension> {
 489    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<D>>,
 490    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<D>>,
 491    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 492    cached_region: Option<MultiBufferRegion<'a, D>>,
 493}
 494
 495#[derive(Clone)]
 496struct MultiBufferRegion<'a, D: TextDimension> {
 497    buffer: &'a BufferSnapshot,
 498    is_main_buffer: bool,
 499    diff_hunk_status: Option<DiffHunkStatus>,
 500    excerpt: &'a Excerpt,
 501    buffer_range: Range<D>,
 502    range: Range<D>,
 503    has_trailing_newline: bool,
 504}
 505
 506struct ExcerptChunks<'a> {
 507    excerpt_id: ExcerptId,
 508    content_chunks: BufferChunks<'a>,
 509    has_footer: bool,
 510}
 511
 512#[derive(Debug)]
 513struct BufferEdit {
 514    range: Range<usize>,
 515    new_text: Arc<str>,
 516    is_insertion: bool,
 517    original_indent_column: Option<u32>,
 518    excerpt_id: ExcerptId,
 519}
 520
 521#[derive(Clone, Copy, Debug, PartialEq)]
 522enum DiffChangeKind {
 523    BufferEdited,
 524    DiffUpdated { base_changed: bool },
 525    ExpandOrCollapseHunks { expand: bool },
 526}
 527
 528#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 529pub enum ExpandExcerptDirection {
 530    Up,
 531    Down,
 532    UpAndDown,
 533}
 534
 535impl ExpandExcerptDirection {
 536    pub fn should_expand_up(&self) -> bool {
 537        match self {
 538            ExpandExcerptDirection::Up => true,
 539            ExpandExcerptDirection::Down => false,
 540            ExpandExcerptDirection::UpAndDown => true,
 541        }
 542    }
 543
 544    pub fn should_expand_down(&self) -> bool {
 545        match self {
 546            ExpandExcerptDirection::Up => false,
 547            ExpandExcerptDirection::Down => true,
 548            ExpandExcerptDirection::UpAndDown => true,
 549        }
 550    }
 551}
 552
 553#[derive(Clone, Debug, PartialEq)]
 554pub struct IndentGuide {
 555    pub buffer_id: BufferId,
 556    pub start_row: MultiBufferRow,
 557    pub end_row: MultiBufferRow,
 558    pub depth: u32,
 559    pub tab_size: u32,
 560    pub settings: IndentGuideSettings,
 561}
 562
 563impl IndentGuide {
 564    pub fn indent_level(&self) -> u32 {
 565        self.depth * self.tab_size
 566    }
 567}
 568
 569impl MultiBuffer {
 570    pub fn new(capability: Capability) -> Self {
 571        Self::new_(
 572            capability,
 573            MultiBufferSnapshot {
 574                show_headers: true,
 575                ..MultiBufferSnapshot::default()
 576            },
 577        )
 578    }
 579
 580    pub fn without_headers(capability: Capability) -> Self {
 581        Self::new_(capability, Default::default())
 582    }
 583
 584    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 585        let mut this = Self::new_(
 586            buffer.read(cx).capability(),
 587            MultiBufferSnapshot {
 588                singleton: true,
 589                ..MultiBufferSnapshot::default()
 590            },
 591        );
 592        this.singleton = true;
 593        this.push_excerpts(
 594            buffer,
 595            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 596            cx,
 597        );
 598        this
 599    }
 600
 601    #[inline]
 602    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
 603        Self {
 604            snapshot: RefCell::new(snapshot),
 605            buffers: Default::default(),
 606            diffs: HashMap::default(),
 607            subscriptions: Topic::default(),
 608            singleton: false,
 609            capability,
 610            title: None,
 611            excerpts_by_path: Default::default(),
 612            paths_by_excerpt: Default::default(),
 613            buffer_changed_since_sync: Default::default(),
 614            history: History::default(),
 615        }
 616    }
 617
 618    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 619        let mut buffers = HashMap::default();
 620        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 621        for (buffer_id, buffer_state) in self.buffers.iter() {
 622            buffer_state.buffer.update(new_cx, |buffer, _| {
 623                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 624            });
 625            buffers.insert(
 626                *buffer_id,
 627                BufferState {
 628                    buffer: buffer_state.buffer.clone(),
 629                    last_version: buffer_state.last_version.clone(),
 630                    last_non_text_state_update_count: buffer_state
 631                        .last_non_text_state_update_count
 632                        .clone(),
 633                    excerpts: buffer_state.excerpts.clone(),
 634                    _subscriptions: [
 635                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 636                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 637                    ],
 638                },
 639            );
 640        }
 641        let mut diff_bases = HashMap::default();
 642        for (buffer_id, diff) in self.diffs.iter() {
 643            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 644        }
 645        Self {
 646            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 647            buffers: buffers,
 648            excerpts_by_path: Default::default(),
 649            paths_by_excerpt: Default::default(),
 650            diffs: diff_bases,
 651            subscriptions: Default::default(),
 652            singleton: self.singleton,
 653            capability: self.capability,
 654            history: self.history.clone(),
 655            title: self.title.clone(),
 656            buffer_changed_since_sync,
 657        }
 658    }
 659
 660    pub fn set_group_interval(&mut self, group_interval: Duration) {
 661        self.history.set_group_interval(group_interval);
 662    }
 663
 664    pub fn with_title(mut self, title: String) -> Self {
 665        self.title = Some(title);
 666        self
 667    }
 668
 669    pub fn read_only(&self) -> bool {
 670        self.capability == Capability::ReadOnly
 671    }
 672
 673    /// Returns an up-to-date snapshot of the MultiBuffer.
 674    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 675        self.sync(cx);
 676        self.snapshot.borrow().clone()
 677    }
 678
 679    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 680        self.sync(cx);
 681        self.snapshot.borrow()
 682    }
 683
 684    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 685        if self.singleton {
 686            Some(self.buffers.values().next().unwrap().buffer.clone())
 687        } else {
 688            None
 689        }
 690    }
 691
 692    pub fn is_singleton(&self) -> bool {
 693        self.singleton
 694    }
 695
 696    pub fn subscribe(&mut self) -> Subscription {
 697        self.subscriptions.subscribe()
 698    }
 699
 700    pub fn is_dirty(&self, cx: &App) -> bool {
 701        self.read(cx).is_dirty()
 702    }
 703
 704    pub fn has_deleted_file(&self, cx: &App) -> bool {
 705        self.read(cx).has_deleted_file()
 706    }
 707
 708    pub fn has_conflict(&self, cx: &App) -> bool {
 709        self.read(cx).has_conflict()
 710    }
 711
 712    // The `is_empty` signature doesn't match what clippy expects
 713    #[allow(clippy::len_without_is_empty)]
 714    pub fn len(&self, cx: &App) -> usize {
 715        self.read(cx).len()
 716    }
 717
 718    pub fn is_empty(&self) -> bool {
 719        self.buffers.is_empty()
 720    }
 721
 722    pub fn edit<I, S, T>(
 723        &mut self,
 724        edits: I,
 725        autoindent_mode: Option<AutoindentMode>,
 726        cx: &mut Context<Self>,
 727    ) where
 728        I: IntoIterator<Item = (Range<S>, T)>,
 729        S: ToOffset,
 730        T: Into<Arc<str>>,
 731    {
 732        if self.read_only() || self.buffers.is_empty() {
 733            return;
 734        }
 735        self.sync_mut(cx);
 736        let edits = edits
 737            .into_iter()
 738            .map(|(range, new_text)| {
 739                let mut range = range.start.to_offset(self.snapshot.get_mut())
 740                    ..range.end.to_offset(self.snapshot.get_mut());
 741                if range.start > range.end {
 742                    mem::swap(&mut range.start, &mut range.end);
 743                }
 744                (range, new_text.into())
 745            })
 746            .collect::<Vec<_>>();
 747
 748        return edit_internal(self, edits, autoindent_mode, cx);
 749
 750        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 751        fn edit_internal(
 752            this: &mut MultiBuffer,
 753            edits: Vec<(Range<usize>, Arc<str>)>,
 754            mut autoindent_mode: Option<AutoindentMode>,
 755            cx: &mut Context<MultiBuffer>,
 756        ) {
 757            let original_indent_columns = match &mut autoindent_mode {
 758                Some(AutoindentMode::Block {
 759                    original_indent_columns,
 760                }) => mem::take(original_indent_columns),
 761                _ => Default::default(),
 762            };
 763
 764            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
 765                edits,
 766                this.snapshot.get_mut(),
 767                &original_indent_columns,
 768            );
 769
 770            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 771            for (buffer_id, mut edits) in buffer_edits {
 772                buffer_ids.push(buffer_id);
 773                edits.sort_by_key(|edit| edit.range.start);
 774                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
 775                    let mut edits = edits.into_iter().peekable();
 776                    let mut insertions = Vec::new();
 777                    let mut original_indent_columns = Vec::new();
 778                    let mut deletions = Vec::new();
 779                    let empty_str: Arc<str> = Arc::default();
 780                    while let Some(BufferEdit {
 781                        mut range,
 782                        mut new_text,
 783                        mut is_insertion,
 784                        original_indent_column,
 785                        excerpt_id,
 786                    }) = edits.next()
 787                    {
 788                        while let Some(BufferEdit {
 789                            range: next_range,
 790                            is_insertion: next_is_insertion,
 791                            new_text: next_new_text,
 792                            excerpt_id: next_excerpt_id,
 793                            ..
 794                        }) = edits.peek()
 795                        {
 796                            if range.end >= next_range.start {
 797                                range.end = cmp::max(next_range.end, range.end);
 798                                is_insertion |= *next_is_insertion;
 799                                if excerpt_id == *next_excerpt_id {
 800                                    new_text = format!("{new_text}{next_new_text}").into();
 801                                }
 802                                edits.next();
 803                            } else {
 804                                break;
 805                            }
 806                        }
 807
 808                        if is_insertion {
 809                            original_indent_columns.push(original_indent_column);
 810                            insertions.push((
 811                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 812                                new_text.clone(),
 813                            ));
 814                        } else if !range.is_empty() {
 815                            deletions.push((
 816                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 817                                empty_str.clone(),
 818                            ));
 819                        }
 820                    }
 821
 822                    let deletion_autoindent_mode =
 823                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 824                            Some(AutoindentMode::Block {
 825                                original_indent_columns: Default::default(),
 826                            })
 827                        } else {
 828                            autoindent_mode.clone()
 829                        };
 830                    let insertion_autoindent_mode =
 831                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 832                            Some(AutoindentMode::Block {
 833                                original_indent_columns,
 834                            })
 835                        } else {
 836                            autoindent_mode.clone()
 837                        };
 838
 839                    buffer.edit(deletions, deletion_autoindent_mode, cx);
 840                    buffer.edit(insertions, insertion_autoindent_mode, cx);
 841                })
 842            }
 843
 844            cx.emit(Event::ExcerptsEdited {
 845                excerpt_ids: edited_excerpt_ids,
 846                buffer_ids,
 847            });
 848        }
 849    }
 850
 851    fn convert_edits_to_buffer_edits(
 852        edits: Vec<(Range<usize>, Arc<str>)>,
 853        snapshot: &MultiBufferSnapshot,
 854        original_indent_columns: &[Option<u32>],
 855    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 856        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 857        let mut edited_excerpt_ids = Vec::new();
 858        let mut cursor = snapshot.cursor::<usize>();
 859        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 860            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 861
 862            cursor.seek(&range.start);
 863            let mut start_region = cursor.region().expect("start offset out of bounds");
 864            if !start_region.is_main_buffer {
 865                cursor.next();
 866                if let Some(region) = cursor.region() {
 867                    start_region = region;
 868                } else {
 869                    continue;
 870                }
 871            }
 872
 873            if range.end < start_region.range.start {
 874                continue;
 875            }
 876
 877            if range.end > start_region.range.end {
 878                cursor.seek_forward(&range.end);
 879            }
 880            let mut end_region = cursor.region().expect("end offset out of bounds");
 881            if !end_region.is_main_buffer {
 882                cursor.prev();
 883                if let Some(region) = cursor.region() {
 884                    end_region = region;
 885                } else {
 886                    continue;
 887                }
 888            }
 889
 890            if range.start > end_region.range.end {
 891                continue;
 892            }
 893
 894            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 895            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 896            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 897                .min(start_region.buffer_range.end);
 898            let buffer_end =
 899                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 900
 901            if start_region.excerpt.id == end_region.excerpt.id {
 902                if start_region.is_main_buffer {
 903                    edited_excerpt_ids.push(start_region.excerpt.id);
 904                    buffer_edits
 905                        .entry(start_region.buffer.remote_id())
 906                        .or_default()
 907                        .push(BufferEdit {
 908                            range: buffer_start..buffer_end,
 909                            new_text,
 910                            is_insertion: true,
 911                            original_indent_column,
 912                            excerpt_id: start_region.excerpt.id,
 913                        });
 914                }
 915            } else {
 916                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 917                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 918                if start_region.is_main_buffer {
 919                    edited_excerpt_ids.push(start_region.excerpt.id);
 920                    buffer_edits
 921                        .entry(start_region.buffer.remote_id())
 922                        .or_default()
 923                        .push(BufferEdit {
 924                            range: start_excerpt_range,
 925                            new_text: new_text.clone(),
 926                            is_insertion: true,
 927                            original_indent_column,
 928                            excerpt_id: start_region.excerpt.id,
 929                        });
 930                }
 931                if end_region.is_main_buffer {
 932                    edited_excerpt_ids.push(end_region.excerpt.id);
 933                    buffer_edits
 934                        .entry(end_region.buffer.remote_id())
 935                        .or_default()
 936                        .push(BufferEdit {
 937                            range: end_excerpt_range,
 938                            new_text: new_text.clone(),
 939                            is_insertion: false,
 940                            original_indent_column,
 941                            excerpt_id: end_region.excerpt.id,
 942                        });
 943                }
 944
 945                cursor.seek(&range.start);
 946                cursor.next_excerpt();
 947                while let Some(region) = cursor.region() {
 948                    if region.excerpt.id == end_region.excerpt.id {
 949                        break;
 950                    }
 951                    if region.is_main_buffer {
 952                        edited_excerpt_ids.push(region.excerpt.id);
 953                        buffer_edits
 954                            .entry(region.buffer.remote_id())
 955                            .or_default()
 956                            .push(BufferEdit {
 957                                range: region.buffer_range,
 958                                new_text: new_text.clone(),
 959                                is_insertion: false,
 960                                original_indent_column,
 961                                excerpt_id: region.excerpt.id,
 962                            });
 963                    }
 964                    cursor.next_excerpt();
 965                }
 966            }
 967        }
 968        (buffer_edits, edited_excerpt_ids)
 969    }
 970
 971    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
 972    where
 973        I: IntoIterator<Item = Range<S>>,
 974        S: ToOffset,
 975    {
 976        if self.read_only() || self.buffers.is_empty() {
 977            return;
 978        }
 979        self.sync_mut(cx);
 980        let empty = Arc::<str>::from("");
 981        let edits = ranges
 982            .into_iter()
 983            .map(|range| {
 984                let mut range = range.start.to_offset(self.snapshot.get_mut())
 985                    ..range.end.to_offset(&self.snapshot.get_mut());
 986                if range.start > range.end {
 987                    mem::swap(&mut range.start, &mut range.end);
 988                }
 989                (range, empty.clone())
 990            })
 991            .collect::<Vec<_>>();
 992
 993        return autoindent_ranges_internal(self, edits, cx);
 994
 995        fn autoindent_ranges_internal(
 996            this: &mut MultiBuffer,
 997            edits: Vec<(Range<usize>, Arc<str>)>,
 998            cx: &mut Context<MultiBuffer>,
 999        ) {
1000            let (buffer_edits, edited_excerpt_ids) =
1001                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1002
1003            let mut buffer_ids = Vec::new();
1004            for (buffer_id, mut edits) in buffer_edits {
1005                buffer_ids.push(buffer_id);
1006                edits.sort_unstable_by_key(|edit| edit.range.start);
1007
1008                let mut ranges: Vec<Range<usize>> = Vec::new();
1009                for edit in edits {
1010                    if let Some(last_range) = ranges.last_mut()
1011                        && edit.range.start <= last_range.end
1012                    {
1013                        last_range.end = last_range.end.max(edit.range.end);
1014                        continue;
1015                    }
1016                    ranges.push(edit.range);
1017                }
1018
1019                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1020                    buffer.autoindent_ranges(ranges, cx);
1021                })
1022            }
1023
1024            cx.emit(Event::ExcerptsEdited {
1025                excerpt_ids: edited_excerpt_ids,
1026                buffer_ids,
1027            });
1028        }
1029    }
1030
1031    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1032    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1033    /// Panics if the given position is invalid.
1034    pub fn insert_empty_line(
1035        &mut self,
1036        position: impl ToPoint,
1037        space_above: bool,
1038        space_below: bool,
1039        cx: &mut Context<Self>,
1040    ) -> Point {
1041        let multibuffer_point = position.to_point(&self.read(cx));
1042        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1043        self.start_transaction(cx);
1044        let empty_line_start = buffer.update(cx, |buffer, cx| {
1045            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1046        });
1047        self.end_transaction(cx);
1048        multibuffer_point + (empty_line_start - buffer_point)
1049    }
1050
1051    pub fn set_active_selections(
1052        &self,
1053        selections: &[Selection<Anchor>],
1054        line_mode: bool,
1055        cursor_shape: CursorShape,
1056        cx: &mut Context<Self>,
1057    ) {
1058        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1059            Default::default();
1060        let snapshot = self.read(cx);
1061        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1062        for selection in selections {
1063            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1064            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1065
1066            cursor.seek(&Some(start_locator), Bias::Left);
1067            while let Some(excerpt) = cursor.item()
1068                && excerpt.locator <= *end_locator
1069            {
1070                let mut start = excerpt.range.context.start;
1071                let mut end = excerpt.range.context.end;
1072                if excerpt.id == selection.start.excerpt_id {
1073                    start = selection.start.text_anchor;
1074                }
1075                if excerpt.id == selection.end.excerpt_id {
1076                    end = selection.end.text_anchor;
1077                }
1078                selections_by_buffer
1079                    .entry(excerpt.buffer_id)
1080                    .or_default()
1081                    .push(Selection {
1082                        id: selection.id,
1083                        start,
1084                        end,
1085                        reversed: selection.reversed,
1086                        goal: selection.goal,
1087                    });
1088
1089                cursor.next();
1090            }
1091        }
1092
1093        for (buffer_id, buffer_state) in self.buffers.iter() {
1094            if !selections_by_buffer.contains_key(buffer_id) {
1095                buffer_state
1096                    .buffer
1097                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1098            }
1099        }
1100
1101        for (buffer_id, mut selections) in selections_by_buffer {
1102            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1103                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1104                let mut selections = selections.into_iter().peekable();
1105                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1106                    let mut selection = selections.next()?;
1107                    while let Some(next_selection) = selections.peek() {
1108                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1109                            let next_selection = selections.next().unwrap();
1110                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1111                                selection.end = next_selection.end;
1112                            }
1113                        } else {
1114                            break;
1115                        }
1116                    }
1117                    Some(selection)
1118                }));
1119                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1120            });
1121        }
1122    }
1123
1124    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1125        for buffer in self.buffers.values() {
1126            buffer
1127                .buffer
1128                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1129        }
1130    }
1131
1132    pub fn push_excerpts<O>(
1133        &mut self,
1134        buffer: Entity<Buffer>,
1135        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1136        cx: &mut Context<Self>,
1137    ) -> Vec<ExcerptId>
1138    where
1139        O: text::ToOffset,
1140    {
1141        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1142    }
1143
1144    fn merge_excerpt_ranges<'a>(
1145        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1146    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1147        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1148        let mut counts: Vec<usize> = Vec::new();
1149        for range in expanded_ranges {
1150            if let Some(last_range) = merged_ranges.last_mut() {
1151                assert!(
1152                    last_range.context.start <= range.context.start,
1153                    "ranges must be sorted: {last_range:?} <= {range:?}"
1154                );
1155                if last_range.context.end >= range.context.start
1156                    || last_range.context.end.row + 1 == range.context.start.row
1157                {
1158                    last_range.context.end = range.context.end.max(last_range.context.end);
1159                    *counts.last_mut().unwrap() += 1;
1160                    continue;
1161                }
1162            }
1163            merged_ranges.push(range.clone());
1164            counts.push(1);
1165        }
1166        (merged_ranges, counts)
1167    }
1168
1169    pub fn insert_excerpts_after<O>(
1170        &mut self,
1171        prev_excerpt_id: ExcerptId,
1172        buffer: Entity<Buffer>,
1173        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1174        cx: &mut Context<Self>,
1175    ) -> Vec<ExcerptId>
1176    where
1177        O: text::ToOffset,
1178    {
1179        let mut ids = Vec::new();
1180        let mut next_excerpt_id =
1181            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1182                last_entry.id.0 + 1
1183            } else {
1184                1
1185            };
1186        self.insert_excerpts_with_ids_after(
1187            prev_excerpt_id,
1188            buffer,
1189            ranges.into_iter().map(|range| {
1190                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1191                ids.push(id);
1192                (id, range)
1193            }),
1194            cx,
1195        );
1196        ids
1197    }
1198
1199    pub fn insert_excerpts_with_ids_after<O>(
1200        &mut self,
1201        prev_excerpt_id: ExcerptId,
1202        buffer: Entity<Buffer>,
1203        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1204        cx: &mut Context<Self>,
1205    ) where
1206        O: text::ToOffset,
1207    {
1208        assert_eq!(self.history.transaction_depth(), 0);
1209        let mut ranges = ranges.into_iter().peekable();
1210        if ranges.peek().is_none() {
1211            return Default::default();
1212        }
1213
1214        self.sync_mut(cx);
1215
1216        let buffer_snapshot = buffer.read(cx).snapshot();
1217        let buffer_id = buffer_snapshot.remote_id();
1218
1219        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1220            self.buffer_changed_since_sync.replace(true);
1221            buffer.update(cx, |buffer, _| {
1222                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1223            });
1224            BufferState {
1225                last_version: RefCell::new(buffer_snapshot.version().clone()),
1226                last_non_text_state_update_count: Cell::new(
1227                    buffer_snapshot.non_text_state_update_count(),
1228                ),
1229                excerpts: Default::default(),
1230                _subscriptions: [
1231                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1232                    cx.subscribe(&buffer, Self::on_buffer_event),
1233                ],
1234                buffer: buffer.clone(),
1235            }
1236        });
1237
1238        let mut snapshot = self.snapshot.get_mut();
1239
1240        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1241        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1242        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1243        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1244        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1245
1246        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1247        new_excerpts.update_last(
1248            |excerpt| {
1249                excerpt.has_trailing_newline = true;
1250            },
1251            (),
1252        );
1253
1254        let next_locator = if let Some(excerpt) = cursor.item() {
1255            excerpt.locator.clone()
1256        } else {
1257            Locator::max()
1258        };
1259
1260        let mut excerpts = Vec::new();
1261        while let Some((id, range)) = ranges.next() {
1262            let locator = Locator::between(&prev_locator, &next_locator);
1263            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1264                buffer_state.excerpts.insert(ix, locator.clone());
1265            }
1266            let range = ExcerptRange {
1267                context: buffer_snapshot.anchor_before(&range.context.start)
1268                    ..buffer_snapshot.anchor_after(&range.context.end),
1269                primary: buffer_snapshot.anchor_before(&range.primary.start)
1270                    ..buffer_snapshot.anchor_after(&range.primary.end),
1271            };
1272            excerpts.push((id, range.clone()));
1273            let excerpt = Excerpt::new(
1274                id,
1275                locator.clone(),
1276                buffer_id,
1277                buffer_snapshot.clone(),
1278                range,
1279                ranges.peek().is_some() || cursor.item().is_some(),
1280            );
1281            new_excerpts.push(excerpt, ());
1282            prev_locator = locator.clone();
1283
1284            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1285                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1286            }
1287            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1288        }
1289
1290        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1291
1292        let suffix = cursor.suffix();
1293        let changed_trailing_excerpt = suffix.is_empty();
1294        new_excerpts.append(suffix, ());
1295        drop(cursor);
1296        snapshot.excerpts = new_excerpts;
1297        snapshot.excerpt_ids = new_excerpt_ids;
1298        if changed_trailing_excerpt {
1299            snapshot.trailing_excerpt_update_count += 1;
1300        }
1301
1302        let edits = Self::sync_diff_transforms(
1303            &mut snapshot,
1304            vec![Edit {
1305                old: edit_start..edit_start,
1306                new: edit_start..edit_end,
1307            }],
1308            DiffChangeKind::BufferEdited,
1309        );
1310        if !edits.is_empty() {
1311            self.subscriptions.publish(edits);
1312        }
1313
1314        cx.emit(Event::Edited {
1315            edited_buffer: None,
1316        });
1317        cx.emit(Event::ExcerptsAdded {
1318            buffer,
1319            predecessor: prev_excerpt_id,
1320            excerpts,
1321        });
1322        cx.notify();
1323    }
1324
1325    pub fn clear(&mut self, cx: &mut Context<Self>) {
1326        self.sync_mut(cx);
1327        let ids = self.excerpt_ids();
1328        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1329        self.excerpts_by_path.clear();
1330        self.paths_by_excerpt.clear();
1331        let MultiBufferSnapshot {
1332            excerpts,
1333            diffs: _,
1334            diff_transforms: _,
1335            non_text_state_update_count: _,
1336            edit_count: _,
1337            is_dirty,
1338            has_deleted_file,
1339            has_conflict,
1340            singleton: _,
1341            excerpt_ids: _,
1342            replaced_excerpts,
1343            trailing_excerpt_update_count,
1344            all_diff_hunks_expanded: _,
1345            show_headers: _,
1346        } = self.snapshot.get_mut();
1347        let start = ExcerptOffset::new(0);
1348        let prev_len = ExcerptOffset::new(excerpts.summary().text.len);
1349        *excerpts = Default::default();
1350        *trailing_excerpt_update_count += 1;
1351        *is_dirty = false;
1352        *has_deleted_file = false;
1353        *has_conflict = false;
1354        replaced_excerpts.clear();
1355
1356        let edits = Self::sync_diff_transforms(
1357            self.snapshot.get_mut(),
1358            vec![Edit {
1359                old: start..prev_len,
1360                new: start..start,
1361            }],
1362            DiffChangeKind::BufferEdited,
1363        );
1364        if !edits.is_empty() {
1365            self.subscriptions.publish(edits);
1366        }
1367        cx.emit(Event::Edited {
1368            edited_buffer: None,
1369        });
1370        cx.emit(Event::ExcerptsRemoved {
1371            ids,
1372            removed_buffer_ids,
1373        });
1374        cx.notify();
1375    }
1376
1377    pub fn excerpts_for_buffer(
1378        &self,
1379        buffer_id: BufferId,
1380        cx: &App,
1381    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1382        let mut excerpts = Vec::new();
1383        let snapshot = self.read(cx);
1384        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1385        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1386            for locator in locators {
1387                cursor.seek_forward(&Some(locator), Bias::Left);
1388                if let Some(excerpt) = cursor.item()
1389                    && excerpt.locator == *locator
1390                {
1391                    excerpts.push((excerpt.id, excerpt.range.clone()));
1392                }
1393            }
1394        }
1395
1396        excerpts
1397    }
1398
1399    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1400        let snapshot = self.read(cx);
1401        let mut excerpts = snapshot
1402            .excerpts
1403            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
1404        let mut diff_transforms = snapshot
1405            .diff_transforms
1406            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
1407        diff_transforms.next();
1408        let locators = self
1409            .buffers
1410            .get(&buffer_id)
1411            .into_iter()
1412            .flat_map(|state| &state.excerpts);
1413        let mut result = Vec::new();
1414        for locator in locators {
1415            excerpts.seek_forward(&Some(locator), Bias::Left);
1416            if let Some(excerpt) = excerpts.item()
1417                && excerpt.locator == *locator
1418            {
1419                let excerpt_start = excerpts.start().1.clone();
1420                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1421
1422                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1423                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
1424                let start = diff_transforms.start().1.0 + overshoot;
1425
1426                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1427                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
1428                let end = diff_transforms.start().1.0 + overshoot;
1429
1430                result.push(start..end)
1431            }
1432        }
1433        result
1434    }
1435
1436    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1437        self.snapshot
1438            .borrow()
1439            .excerpts
1440            .iter()
1441            .map(|entry| entry.buffer_id)
1442            .collect()
1443    }
1444
1445    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1446        self.snapshot
1447            .borrow()
1448            .excerpts
1449            .iter()
1450            .map(|entry| entry.id)
1451            .collect()
1452    }
1453
1454    pub fn excerpt_containing(
1455        &self,
1456        position: impl ToOffset,
1457        cx: &App,
1458    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1459        let snapshot = self.read(cx);
1460        let offset = position.to_offset(&snapshot);
1461
1462        let mut cursor = snapshot.cursor::<usize>();
1463        cursor.seek(&offset);
1464        cursor
1465            .excerpt()
1466            .or_else(|| snapshot.excerpts.last())
1467            .map(|excerpt| {
1468                (
1469                    excerpt.id,
1470                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
1471                    excerpt.range.context.clone(),
1472                )
1473            })
1474    }
1475
1476    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1477        if let Some(buffer_id) = anchor.buffer_id {
1478            self.buffer(buffer_id)
1479        } else {
1480            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
1481            Some(buffer)
1482        }
1483    }
1484
1485    // If point is at the end of the buffer, the last excerpt is returned
1486    pub fn point_to_buffer_offset<T: ToOffset>(
1487        &self,
1488        point: T,
1489        cx: &App,
1490    ) -> Option<(Entity<Buffer>, usize)> {
1491        let snapshot = self.read(cx);
1492        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1493        Some((
1494            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1495            offset,
1496        ))
1497    }
1498
1499    // If point is at the end of the buffer, the last excerpt is returned
1500    pub fn point_to_buffer_point<T: ToPoint>(
1501        &self,
1502        point: T,
1503        cx: &App,
1504    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1505        let snapshot = self.read(cx);
1506        let (buffer, point, is_main_buffer) =
1507            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1508        Some((
1509            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1510            point,
1511            is_main_buffer,
1512        ))
1513    }
1514
1515    pub fn buffer_point_to_anchor(
1516        &self,
1517        buffer: &Entity<Buffer>,
1518        point: Point,
1519        cx: &App,
1520    ) -> Option<Anchor> {
1521        let mut found = None;
1522        let snapshot = buffer.read(cx).snapshot();
1523        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1524            let start = range.context.start.to_point(&snapshot);
1525            let end = range.context.end.to_point(&snapshot);
1526            if start <= point && point < end {
1527                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1528                break;
1529            }
1530            if point < start {
1531                found = Some((start, excerpt_id));
1532            }
1533            if point > end {
1534                found = Some((end, excerpt_id));
1535            }
1536        }
1537
1538        found.map(|(point, excerpt_id)| {
1539            let text_anchor = snapshot.anchor_after(point);
1540            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1541        })
1542    }
1543
1544    pub fn buffer_anchor_to_anchor(
1545        &self,
1546        buffer: &Entity<Buffer>,
1547        anchor: text::Anchor,
1548        cx: &App,
1549    ) -> Option<Anchor> {
1550        let snapshot = buffer.read(cx).snapshot();
1551        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1552            if range.context.start.cmp(&anchor, &snapshot).is_le()
1553                && range.context.end.cmp(&anchor, &snapshot).is_ge()
1554            {
1555                return Some(Anchor::in_buffer(excerpt_id, snapshot.remote_id(), anchor));
1556            }
1557        }
1558
1559        None
1560    }
1561
1562    pub fn remove_excerpts(
1563        &mut self,
1564        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1565        cx: &mut Context<Self>,
1566    ) {
1567        self.sync_mut(cx);
1568        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1569        if ids.is_empty() {
1570            return;
1571        }
1572        self.buffer_changed_since_sync.replace(true);
1573
1574        let mut snapshot = self.snapshot.get_mut();
1575        let mut new_excerpts = SumTree::default();
1576        let mut cursor = snapshot
1577            .excerpts
1578            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1579        let mut edits = Vec::new();
1580        let mut excerpt_ids = ids.iter().copied().peekable();
1581        let mut removed_buffer_ids = Vec::new();
1582
1583        while let Some(excerpt_id) = excerpt_ids.next() {
1584            self.paths_by_excerpt.remove(&excerpt_id);
1585            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1586            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1587            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
1588
1589            if let Some(mut excerpt) = cursor.item() {
1590                if excerpt.id != excerpt_id {
1591                    continue;
1592                }
1593                let mut old_start = cursor.start().1;
1594
1595                // Skip over the removed excerpt.
1596                'remove_excerpts: loop {
1597                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
1598                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1599                        if buffer_state.excerpts.is_empty() {
1600                            log::debug!(
1601                                "removing buffer and diff for buffer {}",
1602                                excerpt.buffer_id
1603                            );
1604                            self.buffers.remove(&excerpt.buffer_id);
1605                            removed_buffer_ids.push(excerpt.buffer_id);
1606                        }
1607                    }
1608                    cursor.next();
1609
1610                    // Skip over any subsequent excerpts that are also removed.
1611                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1612                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1613                        if let Some(next_excerpt) = cursor.item()
1614                            && next_excerpt.locator == *next_locator
1615                        {
1616                            excerpt_ids.next();
1617                            excerpt = next_excerpt;
1618                            continue 'remove_excerpts;
1619                        }
1620                    }
1621
1622                    break;
1623                }
1624
1625                // When removing the last excerpt, remove the trailing newline from
1626                // the previous excerpt.
1627                if cursor.item().is_none() && old_start.value > 0 {
1628                    old_start.value -= 1;
1629                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
1630                }
1631
1632                // Push an edit for the removal of this run of excerpts.
1633                let old_end = cursor.start().1;
1634                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1635                edits.push(Edit {
1636                    old: old_start..old_end,
1637                    new: new_start..new_start,
1638                });
1639            }
1640        }
1641        let suffix = cursor.suffix();
1642        let changed_trailing_excerpt = suffix.is_empty();
1643        new_excerpts.append(suffix, ());
1644        drop(cursor);
1645        snapshot.excerpts = new_excerpts;
1646        for buffer_id in &removed_buffer_ids {
1647            self.diffs.remove(buffer_id);
1648            snapshot.diffs.remove(buffer_id);
1649        }
1650
1651        if changed_trailing_excerpt {
1652            snapshot.trailing_excerpt_update_count += 1;
1653        }
1654
1655        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
1656        if !edits.is_empty() {
1657            self.subscriptions.publish(edits);
1658        }
1659        cx.emit(Event::Edited {
1660            edited_buffer: None,
1661        });
1662        cx.emit(Event::ExcerptsRemoved {
1663            ids,
1664            removed_buffer_ids,
1665        });
1666        cx.notify();
1667    }
1668
1669    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1670        &self,
1671        anchors: Anchors,
1672        cx: &mut Context<Self>,
1673    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1674        let mut error = None;
1675        let mut futures = Vec::new();
1676        for anchor in anchors {
1677            if let Some(buffer_id) = anchor.buffer_id {
1678                if let Some(buffer) = self.buffers.get(&buffer_id) {
1679                    buffer.buffer.update(cx, |buffer, _| {
1680                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1681                    });
1682                } else {
1683                    error = Some(anyhow!(
1684                        "buffer {buffer_id} is not part of this multi-buffer"
1685                    ));
1686                    break;
1687                }
1688            }
1689        }
1690        async move {
1691            if let Some(error) = error {
1692                Err(error)?;
1693            }
1694            for future in futures {
1695                future.await?;
1696            }
1697            Ok(())
1698        }
1699    }
1700
1701    pub fn text_anchor_for_position<T: ToOffset>(
1702        &self,
1703        position: T,
1704        cx: &App,
1705    ) -> Option<(Entity<Buffer>, language::Anchor)> {
1706        let snapshot = self.read(cx);
1707        let anchor = snapshot.anchor_before(position);
1708        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
1709        Some((buffer, anchor.text_anchor))
1710    }
1711
1712    fn on_buffer_event(
1713        &mut self,
1714        buffer: Entity<Buffer>,
1715        event: &language::BufferEvent,
1716        cx: &mut Context<Self>,
1717    ) {
1718        use language::BufferEvent;
1719        cx.emit(match event {
1720            BufferEvent::Edited => Event::Edited {
1721                edited_buffer: Some(buffer),
1722            },
1723            BufferEvent::DirtyChanged => Event::DirtyChanged,
1724            BufferEvent::Saved => Event::Saved,
1725            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1726            BufferEvent::Reloaded => Event::Reloaded,
1727            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
1728            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1729            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1730            BufferEvent::CapabilityChanged => {
1731                self.capability = buffer.read(cx).capability();
1732                return;
1733            }
1734            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1735        });
1736    }
1737
1738    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1739        let diff = diff.read(cx);
1740        let buffer_id = diff.buffer_id;
1741        let diff = diff.snapshot(cx);
1742        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
1743    }
1744
1745    fn buffer_diff_changed(
1746        &mut self,
1747        diff: Entity<BufferDiff>,
1748        range: Range<text::Anchor>,
1749        cx: &mut Context<Self>,
1750    ) {
1751        self.sync_mut(cx);
1752
1753        let diff = diff.read(cx);
1754        let buffer_id = diff.buffer_id;
1755        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
1756            return;
1757        };
1758        self.buffer_changed_since_sync.replace(true);
1759
1760        let buffer = buffer_state.buffer.read(cx);
1761        let diff_change_range = range.to_offset(buffer);
1762
1763        let new_diff = diff.snapshot(cx);
1764        let mut snapshot = self.snapshot.get_mut();
1765        let base_text_changed = snapshot
1766            .diffs
1767            .get(&buffer_id)
1768            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
1769
1770        snapshot.diffs.insert(buffer_id, new_diff);
1771
1772        let mut excerpt_edits = Vec::new();
1773        for locator in &buffer_state.excerpts {
1774            let mut cursor = snapshot
1775                .excerpts
1776                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1777            cursor.seek_forward(&Some(locator), Bias::Left);
1778            if let Some(excerpt) = cursor.item()
1779                && excerpt.locator == *locator
1780            {
1781                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
1782                if diff_change_range.end < excerpt_buffer_range.start
1783                    || diff_change_range.start > excerpt_buffer_range.end
1784                {
1785                    continue;
1786                }
1787                let excerpt_start = cursor.start().1;
1788                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
1789                let diff_change_start_in_excerpt = ExcerptOffset::new(
1790                    diff_change_range
1791                        .start
1792                        .saturating_sub(excerpt_buffer_range.start),
1793                );
1794                let diff_change_end_in_excerpt = ExcerptOffset::new(
1795                    diff_change_range
1796                        .end
1797                        .saturating_sub(excerpt_buffer_range.start),
1798                );
1799                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
1800                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
1801                excerpt_edits.push(Edit {
1802                    old: edit_start..edit_end,
1803                    new: edit_start..edit_end,
1804                });
1805            }
1806        }
1807
1808        let edits = Self::sync_diff_transforms(
1809            &mut snapshot,
1810            excerpt_edits,
1811            DiffChangeKind::DiffUpdated {
1812                base_changed: base_text_changed,
1813            },
1814        );
1815        if !edits.is_empty() {
1816            self.subscriptions.publish(edits);
1817        }
1818        cx.emit(Event::Edited {
1819            edited_buffer: None,
1820        });
1821    }
1822
1823    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
1824        self.buffers
1825            .values()
1826            .map(|state| state.buffer.clone())
1827            .collect()
1828    }
1829
1830    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
1831        self.buffers.keys().copied().collect()
1832    }
1833
1834    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
1835        self.buffers
1836            .get(&buffer_id)
1837            .map(|state| state.buffer.clone())
1838    }
1839
1840    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
1841        self.point_to_buffer_offset(point, cx)
1842            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
1843    }
1844
1845    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
1846        let buffer_id = self
1847            .snapshot
1848            .borrow()
1849            .excerpts
1850            .first()
1851            .map(|excerpt| excerpt.buffer.remote_id());
1852        buffer_id
1853            .and_then(|buffer_id| self.buffer(buffer_id))
1854            .map(|buffer| {
1855                let buffer = buffer.read(cx);
1856                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
1857            })
1858            .unwrap_or_else(move || self.language_settings_at(0, cx))
1859    }
1860
1861    pub fn language_settings_at<'a, T: ToOffset>(
1862        &'a self,
1863        point: T,
1864        cx: &'a App,
1865    ) -> Cow<'a, LanguageSettings> {
1866        let mut language = None;
1867        let mut file = None;
1868        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
1869            let buffer = buffer.read(cx);
1870            language = buffer.language_at(offset);
1871            file = buffer.file();
1872        }
1873        language_settings(language.map(|l| l.name()), file, cx)
1874    }
1875
1876    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
1877        self.buffers.values().for_each(|state| f(&state.buffer))
1878    }
1879
1880    pub fn explicit_title(&self) -> Option<&str> {
1881        self.title.as_deref()
1882    }
1883
1884    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
1885        if let Some(title) = self.title.as_ref() {
1886            return title.into();
1887        }
1888
1889        if let Some(buffer) = self.as_singleton() {
1890            let buffer = buffer.read(cx);
1891
1892            if let Some(file) = buffer.file() {
1893                return file.file_name(cx).into();
1894            }
1895
1896            if let Some(title) = self.buffer_content_title(buffer) {
1897                return title;
1898            }
1899        };
1900
1901        "untitled".into()
1902    }
1903
1904    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
1905        let mut is_leading_whitespace = true;
1906        let mut count = 0;
1907        let mut prev_was_space = false;
1908        let mut title = String::new();
1909
1910        for ch in buffer.snapshot().chars() {
1911            if is_leading_whitespace && ch.is_whitespace() {
1912                continue;
1913            }
1914
1915            is_leading_whitespace = false;
1916
1917            if ch == '\n' || count >= 40 {
1918                break;
1919            }
1920
1921            if ch.is_whitespace() {
1922                if !prev_was_space {
1923                    title.push(' ');
1924                    count += 1;
1925                    prev_was_space = true;
1926                }
1927            } else {
1928                title.push(ch);
1929                count += 1;
1930                prev_was_space = false;
1931            }
1932        }
1933
1934        let title = title.trim_end().to_string();
1935
1936        if title.is_empty() {
1937            return None;
1938        }
1939
1940        Some(title.into())
1941    }
1942
1943    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
1944        self.title = Some(title);
1945        cx.notify();
1946    }
1947
1948    /// Preserve preview tabs containing this multibuffer until additional edits occur.
1949    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
1950        for buffer_state in self.buffers.values() {
1951            buffer_state
1952                .buffer
1953                .update(cx, |buffer, _cx| buffer.refresh_preview());
1954        }
1955    }
1956
1957    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
1958    pub fn preserve_preview(&self, cx: &App) -> bool {
1959        self.buffers
1960            .values()
1961            .all(|state| state.buffer.read(cx).preserve_preview())
1962    }
1963
1964    #[cfg(any(test, feature = "test-support"))]
1965    pub fn is_parsing(&self, cx: &App) -> bool {
1966        self.as_singleton().unwrap().read(cx).is_parsing()
1967    }
1968
1969    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1970        let buffer_id = diff.read(cx).buffer_id;
1971        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
1972        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
1973    }
1974
1975    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
1976        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
1977    }
1978
1979    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
1980        self.expand_or_collapse_diff_hunks(ranges, true, cx);
1981    }
1982
1983    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
1984        self.expand_or_collapse_diff_hunks(ranges, false, cx);
1985    }
1986
1987    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
1988        self.snapshot.get_mut().all_diff_hunks_expanded = true;
1989        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
1990    }
1991
1992    pub fn all_diff_hunks_expanded(&self) -> bool {
1993        self.snapshot.borrow().all_diff_hunks_expanded
1994    }
1995
1996    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
1997        self.snapshot.get_mut().all_diff_hunks_expanded = false;
1998        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
1999    }
2000
2001    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2002        self.read(cx)
2003            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2004            .nth(1)
2005            .is_some()
2006    }
2007
2008    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2009        let snapshot = self.read(cx);
2010        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2011        let offset_range = range.to_offset(&snapshot);
2012        cursor.seek(&offset_range.start, Bias::Left);
2013        while let Some(item) = cursor.item() {
2014            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2015                break;
2016            }
2017            if item.hunk_info().is_some() {
2018                return true;
2019            }
2020            cursor.next();
2021        }
2022        false
2023    }
2024
2025    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2026        let snapshot = self.read(cx);
2027        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2028        for range in ranges {
2029            let range = range.to_point(&snapshot);
2030            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2031            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2032            let start = start.saturating_sub(1);
2033            let end = snapshot.len().min(end + 1);
2034            cursor.seek(&start, Bias::Right);
2035            while let Some(item) = cursor.item() {
2036                if *cursor.start() >= end {
2037                    break;
2038                }
2039                if item.hunk_info().is_some() {
2040                    return true;
2041                }
2042                cursor.next();
2043            }
2044        }
2045        false
2046    }
2047
2048    pub fn expand_or_collapse_diff_hunks_inner(
2049        &mut self,
2050        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2051        expand: bool,
2052        cx: &mut Context<Self>,
2053    ) {
2054        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2055            return;
2056        }
2057        self.sync_mut(cx);
2058        let mut snapshot = self.snapshot.get_mut();
2059        let mut excerpt_edits = Vec::new();
2060        let mut last_hunk_row = None;
2061        for (range, end_excerpt_id) in ranges {
2062            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2063                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2064                    continue;
2065                }
2066                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2067                    continue;
2068                }
2069                let start = Anchor::in_buffer(
2070                    diff_hunk.excerpt_id,
2071                    diff_hunk.buffer_id,
2072                    diff_hunk.buffer_range.start,
2073                );
2074                let end = Anchor::in_buffer(
2075                    diff_hunk.excerpt_id,
2076                    diff_hunk.buffer_id,
2077                    diff_hunk.buffer_range.end,
2078                );
2079                let start = snapshot.excerpt_offset_for_anchor(&start);
2080                let end = snapshot.excerpt_offset_for_anchor(&end);
2081                last_hunk_row = Some(diff_hunk.row_range.start);
2082                excerpt_edits.push(text::Edit {
2083                    old: start..end,
2084                    new: start..end,
2085                });
2086            }
2087        }
2088
2089        let edits = Self::sync_diff_transforms(
2090            &mut snapshot,
2091            excerpt_edits,
2092            DiffChangeKind::ExpandOrCollapseHunks { expand },
2093        );
2094        if !edits.is_empty() {
2095            self.subscriptions.publish(edits);
2096        }
2097        cx.emit(Event::DiffHunksToggled);
2098        cx.emit(Event::Edited {
2099            edited_buffer: None,
2100        });
2101    }
2102
2103    pub fn expand_or_collapse_diff_hunks(
2104        &mut self,
2105        ranges: Vec<Range<Anchor>>,
2106        expand: bool,
2107        cx: &mut Context<Self>,
2108    ) {
2109        let snapshot = self.snapshot.borrow().clone();
2110        let ranges = ranges.iter().map(move |range| {
2111            let end_excerpt_id = range.end.excerpt_id;
2112            let range = range.to_point(&snapshot);
2113            let mut peek_end = range.end;
2114            if range.end.row < snapshot.max_row().0 {
2115                peek_end = Point::new(range.end.row + 1, 0);
2116            };
2117            (range.start..peek_end, end_excerpt_id)
2118        });
2119        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2120    }
2121
2122    pub fn resize_excerpt(
2123        &mut self,
2124        id: ExcerptId,
2125        range: Range<text::Anchor>,
2126        cx: &mut Context<Self>,
2127    ) {
2128        self.sync_mut(cx);
2129
2130        let mut snapshot = self.snapshot.get_mut();
2131        let locator = snapshot.excerpt_locator_for_id(id);
2132        let mut new_excerpts = SumTree::default();
2133        let mut cursor = snapshot
2134            .excerpts
2135            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2136        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2137
2138        let prefix = cursor.slice(&Some(locator), Bias::Left);
2139        new_excerpts.append(prefix, ());
2140
2141        let mut excerpt = cursor.item().unwrap().clone();
2142        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2143
2144        excerpt.range.context.start = range.start;
2145        excerpt.range.context.end = range.end;
2146        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2147
2148        excerpt.text_summary = excerpt
2149            .buffer
2150            .text_summary_for_range(excerpt.range.context.clone());
2151
2152        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2153        let old_start_offset = cursor.start().1;
2154        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2155        let edit = Edit {
2156            old: old_start_offset..old_start_offset + old_text_len,
2157            new: new_start_offset..new_start_offset + new_text_len,
2158        };
2159
2160        if let Some(last_edit) = edits.last_mut() {
2161            if last_edit.old.end == edit.old.start {
2162                last_edit.old.end = edit.old.end;
2163                last_edit.new.end = edit.new.end;
2164            } else {
2165                edits.push(edit);
2166            }
2167        } else {
2168            edits.push(edit);
2169        }
2170
2171        new_excerpts.push(excerpt, ());
2172
2173        cursor.next();
2174
2175        new_excerpts.append(cursor.suffix(), ());
2176
2177        drop(cursor);
2178        snapshot.excerpts = new_excerpts;
2179
2180        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2181        if !edits.is_empty() {
2182            self.subscriptions.publish(edits);
2183        }
2184        cx.emit(Event::Edited {
2185            edited_buffer: None,
2186        });
2187        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2188        cx.notify();
2189    }
2190
2191    pub fn expand_excerpts(
2192        &mut self,
2193        ids: impl IntoIterator<Item = ExcerptId>,
2194        line_count: u32,
2195        direction: ExpandExcerptDirection,
2196        cx: &mut Context<Self>,
2197    ) {
2198        if line_count == 0 {
2199            return;
2200        }
2201        self.sync_mut(cx);
2202        if !self.excerpts_by_path.is_empty() {
2203            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2204            return;
2205        }
2206        let mut snapshot = self.snapshot.get_mut();
2207
2208        let ids = ids.into_iter().collect::<Vec<_>>();
2209        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2210        let mut new_excerpts = SumTree::default();
2211        let mut cursor = snapshot
2212            .excerpts
2213            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2214        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2215
2216        for locator in &locators {
2217            let prefix = cursor.slice(&Some(locator), Bias::Left);
2218            new_excerpts.append(prefix, ());
2219
2220            let mut excerpt = cursor.item().unwrap().clone();
2221            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2222
2223            let up_line_count = if direction.should_expand_up() {
2224                line_count
2225            } else {
2226                0
2227            };
2228
2229            let start_row = excerpt
2230                .range
2231                .context
2232                .start
2233                .to_point(&excerpt.buffer)
2234                .row
2235                .saturating_sub(up_line_count);
2236            let start_point = Point::new(start_row, 0);
2237            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2238
2239            let down_line_count = if direction.should_expand_down() {
2240                line_count
2241            } else {
2242                0
2243            };
2244
2245            let mut end_point = excerpt.buffer.clip_point(
2246                excerpt.range.context.end.to_point(&excerpt.buffer)
2247                    + Point::new(down_line_count, 0),
2248                Bias::Left,
2249            );
2250            end_point.column = excerpt.buffer.line_len(end_point.row);
2251            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2252            excerpt.max_buffer_row = end_point.row;
2253
2254            excerpt.text_summary = excerpt
2255                .buffer
2256                .text_summary_for_range(excerpt.range.context.clone());
2257
2258            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2259            let old_start_offset = cursor.start().1;
2260            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2261            let edit = Edit {
2262                old: old_start_offset..old_start_offset + old_text_len,
2263                new: new_start_offset..new_start_offset + new_text_len,
2264            };
2265
2266            if let Some(last_edit) = edits.last_mut() {
2267                if last_edit.old.end == edit.old.start {
2268                    last_edit.old.end = edit.old.end;
2269                    last_edit.new.end = edit.new.end;
2270                } else {
2271                    edits.push(edit);
2272                }
2273            } else {
2274                edits.push(edit);
2275            }
2276
2277            new_excerpts.push(excerpt, ());
2278
2279            cursor.next();
2280        }
2281
2282        new_excerpts.append(cursor.suffix(), ());
2283
2284        drop(cursor);
2285        snapshot.excerpts = new_excerpts;
2286
2287        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2288        if !edits.is_empty() {
2289            self.subscriptions.publish(edits);
2290        }
2291        cx.emit(Event::Edited {
2292            edited_buffer: None,
2293        });
2294        cx.emit(Event::ExcerptsExpanded { ids });
2295        cx.notify();
2296    }
2297
2298    fn sync(&self, cx: &App) {
2299        let changed = self.buffer_changed_since_sync.replace(false);
2300        if !changed {
2301            return;
2302        }
2303        let edits = Self::sync_(
2304            &mut self.snapshot.borrow_mut(),
2305            &self.buffers,
2306            &self.diffs,
2307            cx,
2308        );
2309        if !edits.is_empty() {
2310            self.subscriptions.publish(edits);
2311        }
2312    }
2313
2314    fn sync_mut(&mut self, cx: &App) {
2315        let changed = self.buffer_changed_since_sync.replace(false);
2316        if !changed {
2317            return;
2318        }
2319        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2320
2321        if !edits.is_empty() {
2322            self.subscriptions.publish(edits);
2323        }
2324    }
2325
2326    fn sync_(
2327        snapshot: &mut MultiBufferSnapshot,
2328        buffers: &HashMap<BufferId, BufferState>,
2329        diffs: &HashMap<BufferId, DiffState>,
2330        cx: &App,
2331    ) -> Vec<Edit<usize>> {
2332        let MultiBufferSnapshot {
2333            excerpts,
2334            diffs: buffer_diff,
2335            diff_transforms: _,
2336            non_text_state_update_count,
2337            edit_count,
2338            is_dirty,
2339            has_deleted_file,
2340            has_conflict,
2341            singleton: _,
2342            excerpt_ids: _,
2343            replaced_excerpts: _,
2344            trailing_excerpt_update_count: _,
2345            all_diff_hunks_expanded: _,
2346            show_headers: _,
2347        } = snapshot;
2348        *is_dirty = false;
2349        *has_deleted_file = false;
2350        *has_conflict = false;
2351
2352        let mut excerpts_to_edit = Vec::new();
2353        let mut non_text_state_updated = false;
2354        let mut edited = false;
2355        for buffer_state in buffers.values() {
2356            let buffer = buffer_state.buffer.read(cx);
2357            let version = buffer.version();
2358            let non_text_state_update_count = buffer.non_text_state_update_count();
2359
2360            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2361            let buffer_non_text_state_updated =
2362                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2363            if buffer_edited || buffer_non_text_state_updated {
2364                *buffer_state.last_version.borrow_mut() = version;
2365                buffer_state
2366                    .last_non_text_state_update_count
2367                    .set(non_text_state_update_count);
2368                excerpts_to_edit.extend(
2369                    buffer_state
2370                        .excerpts
2371                        .iter()
2372                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2373                );
2374            }
2375
2376            edited |= buffer_edited;
2377            non_text_state_updated |= buffer_non_text_state_updated;
2378            *is_dirty |= buffer.is_dirty();
2379            *has_deleted_file |= buffer
2380                .file()
2381                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2382            *has_conflict |= buffer.has_conflict();
2383        }
2384        if edited {
2385            *edit_count += 1;
2386        }
2387        if non_text_state_updated {
2388            *non_text_state_update_count += 1;
2389        }
2390
2391        for (id, diff) in diffs.iter() {
2392            if buffer_diff.get(id).is_none() {
2393                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2394            }
2395        }
2396
2397        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2398
2399        let mut edits = Vec::new();
2400        let mut new_excerpts = SumTree::default();
2401        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2402
2403        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2404            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2405            let old_excerpt = cursor.item().unwrap();
2406            let buffer = buffer.read(cx);
2407            let buffer_id = buffer.remote_id();
2408
2409            let mut new_excerpt;
2410            if buffer_edited {
2411                edits.extend(
2412                    buffer
2413                        .edits_since_in_range::<usize>(
2414                            old_excerpt.buffer.version(),
2415                            old_excerpt.range.context.clone(),
2416                        )
2417                        .map(|edit| {
2418                            let excerpt_old_start = cursor.start().1;
2419                            let excerpt_new_start =
2420                                ExcerptOffset::new(new_excerpts.summary().text.len);
2421                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2422                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2423                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2424                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2425                            Edit {
2426                                old: old_start..old_end,
2427                                new: new_start..new_end,
2428                            }
2429                        }),
2430                );
2431
2432                new_excerpt = Excerpt::new(
2433                    old_excerpt.id,
2434                    locator.clone(),
2435                    buffer_id,
2436                    buffer.snapshot(),
2437                    old_excerpt.range.clone(),
2438                    old_excerpt.has_trailing_newline,
2439                );
2440            } else {
2441                new_excerpt = old_excerpt.clone();
2442                new_excerpt.buffer = buffer.snapshot();
2443            }
2444
2445            new_excerpts.push(new_excerpt, ());
2446            cursor.next();
2447        }
2448        new_excerpts.append(cursor.suffix(), ());
2449
2450        drop(cursor);
2451        *excerpts = new_excerpts;
2452        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2453    }
2454
2455    fn sync_diff_transforms(
2456        snapshot: &mut MultiBufferSnapshot,
2457        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2458        change_kind: DiffChangeKind,
2459    ) -> Vec<Edit<usize>> {
2460        if excerpt_edits.is_empty() {
2461            return vec![];
2462        }
2463
2464        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2465        let mut old_diff_transforms = snapshot
2466            .diff_transforms
2467            .cursor::<Dimensions<ExcerptOffset, usize>>(());
2468        let mut new_diff_transforms = SumTree::default();
2469        let mut old_expanded_hunks = HashSet::default();
2470        let mut output_edits = Vec::new();
2471        let mut output_delta = 0_isize;
2472        let mut at_transform_boundary = true;
2473        let mut end_of_current_insert = None;
2474
2475        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2476        while let Some(edit) = excerpt_edits.next() {
2477            excerpts.seek_forward(&edit.new.start, Bias::Right);
2478            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2479                excerpts.prev();
2480            }
2481
2482            // Keep any transforms that are before the edit.
2483            if at_transform_boundary {
2484                at_transform_boundary = false;
2485                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2486                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2487                if let Some(transform) = old_diff_transforms.item()
2488                    && old_diff_transforms.end().0 == edit.old.start
2489                    && old_diff_transforms.start().0 < edit.old.start
2490                {
2491                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2492                    old_diff_transforms.next();
2493                }
2494            }
2495
2496            // Compute the start of the edit in output coordinates.
2497            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2498            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2499            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2500
2501            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2502                &edit,
2503                &mut excerpts,
2504                &mut old_diff_transforms,
2505                &mut new_diff_transforms,
2506                &mut end_of_current_insert,
2507                &mut old_expanded_hunks,
2508                snapshot,
2509                change_kind,
2510            );
2511
2512            // Compute the end of the edit in output coordinates.
2513            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2514            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2515            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2516            let edit_new_end =
2517                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2518            let output_edit = Edit {
2519                old: edit_old_start..edit_old_end,
2520                new: edit_new_start..edit_new_end,
2521            };
2522
2523            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2524            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2525            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2526                output_edits.push(output_edit);
2527            }
2528
2529            // If this is the last edit that intersects the current diff transform,
2530            // then recreate the content up to the end of this transform, to prepare
2531            // for reusing additional slices of the old transforms.
2532            if excerpt_edits
2533                .peek()
2534                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2535            {
2536                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2537                    && match old_diff_transforms.item() {
2538                        Some(DiffTransform::BufferContent {
2539                            inserted_hunk_info: Some(hunk),
2540                            ..
2541                        }) => excerpts.item().is_some_and(|excerpt| {
2542                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2543                        }),
2544                        _ => true,
2545                    };
2546
2547                let mut excerpt_offset = edit.new.end;
2548                if !keep_next_old_transform {
2549                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2550                    old_diff_transforms.next();
2551                }
2552
2553                old_expanded_hunks.clear();
2554                Self::push_buffer_content_transform(
2555                    snapshot,
2556                    &mut new_diff_transforms,
2557                    excerpt_offset,
2558                    end_of_current_insert,
2559                );
2560                at_transform_boundary = true;
2561            }
2562        }
2563
2564        // Keep any transforms that are after the last edit.
2565        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2566
2567        // Ensure there's always at least one buffer content transform.
2568        if new_diff_transforms.is_empty() {
2569            new_diff_transforms.push(
2570                DiffTransform::BufferContent {
2571                    summary: Default::default(),
2572                    inserted_hunk_info: None,
2573                },
2574                (),
2575            );
2576        }
2577
2578        drop(old_diff_transforms);
2579        drop(excerpts);
2580        snapshot.diff_transforms = new_diff_transforms;
2581        snapshot.edit_count += 1;
2582
2583        #[cfg(any(test, feature = "test-support"))]
2584        snapshot.check_invariants();
2585        output_edits
2586    }
2587
2588    fn recompute_diff_transforms_for_edit(
2589        edit: &Edit<TypedOffset<Excerpt>>,
2590        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2591        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
2592        new_diff_transforms: &mut SumTree<DiffTransform>,
2593        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2594        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2595        snapshot: &MultiBufferSnapshot,
2596        change_kind: DiffChangeKind,
2597    ) -> bool {
2598        log::trace!(
2599            "recomputing diff transform for edit {:?} => {:?}",
2600            edit.old.start.value..edit.old.end.value,
2601            edit.new.start.value..edit.new.end.value
2602        );
2603
2604        // Record which hunks were previously expanded.
2605        while let Some(item) = old_diff_transforms.item() {
2606            if let Some(hunk_info) = item.hunk_info() {
2607                log::trace!(
2608                    "previously expanded hunk at {}",
2609                    old_diff_transforms.start().0
2610                );
2611                old_expanded_hunks.insert(hunk_info);
2612            }
2613            if old_diff_transforms.end().0 > edit.old.end {
2614                break;
2615            }
2616            old_diff_transforms.next();
2617        }
2618
2619        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2620        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2621        if old_expanded_hunks.is_empty()
2622            && change_kind == DiffChangeKind::BufferEdited
2623            && !all_diff_hunks_expanded
2624        {
2625            return false;
2626        }
2627
2628        // Visit each excerpt that intersects the edit.
2629        let mut did_expand_hunks = false;
2630        while let Some(excerpt) = excerpts.item() {
2631            // Recompute the expanded hunks in the portion of the excerpt that
2632            // intersects the edit.
2633            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2634                let buffer = &excerpt.buffer;
2635                let excerpt_start = *excerpts.start();
2636                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2637                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2638                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2639                let edit_buffer_start =
2640                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2641                let edit_buffer_end =
2642                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2643                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2644                let edit_anchor_range =
2645                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2646
2647                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2648                    if hunk.is_created_file() && !all_diff_hunks_expanded {
2649                        continue;
2650                    }
2651
2652                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2653                    if hunk_buffer_range.start < excerpt_buffer_start {
2654                        log::trace!("skipping hunk that starts before excerpt");
2655                        continue;
2656                    }
2657
2658                    let hunk_info = DiffTransformHunkInfo {
2659                        excerpt_id: excerpt.id,
2660                        hunk_start_anchor: hunk.buffer_range.start,
2661                        hunk_secondary_status: hunk.secondary_status,
2662                    };
2663
2664                    let hunk_excerpt_start = excerpt_start
2665                        + ExcerptOffset::new(
2666                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2667                        );
2668                    let hunk_excerpt_end = excerpt_end.min(
2669                        excerpt_start
2670                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2671                    );
2672
2673                    Self::push_buffer_content_transform(
2674                        snapshot,
2675                        new_diff_transforms,
2676                        hunk_excerpt_start,
2677                        *end_of_current_insert,
2678                    );
2679
2680                    // For every existing hunk, determine if it was previously expanded
2681                    // and if it should currently be expanded.
2682                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2683                    let should_expand_hunk = match &change_kind {
2684                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2685                            was_previously_expanded || all_diff_hunks_expanded
2686                        }
2687                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2688                            let intersects = hunk_buffer_range.is_empty()
2689                                || hunk_buffer_range.end > edit_buffer_start;
2690                            if *expand {
2691                                intersects || was_previously_expanded || all_diff_hunks_expanded
2692                            } else {
2693                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
2694                            }
2695                        }
2696                        _ => was_previously_expanded || all_diff_hunks_expanded,
2697                    };
2698
2699                    if should_expand_hunk {
2700                        did_expand_hunks = true;
2701                        log::trace!(
2702                            "expanding hunk {:?}, excerpt:{:?}",
2703                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2704                            excerpt.id
2705                        );
2706
2707                        if !hunk.diff_base_byte_range.is_empty()
2708                            && hunk_buffer_range.start >= edit_buffer_start
2709                            && hunk_buffer_range.start <= excerpt_buffer_end
2710                        {
2711                            let base_text = diff.base_text();
2712                            let mut text_cursor =
2713                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2714                            let mut base_text_summary =
2715                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2716
2717                            let mut has_trailing_newline = false;
2718                            if base_text_summary.last_line_chars > 0 {
2719                                base_text_summary += TextSummary::newline();
2720                                has_trailing_newline = true;
2721                            }
2722
2723                            new_diff_transforms.push(
2724                                DiffTransform::DeletedHunk {
2725                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2726                                    summary: base_text_summary,
2727                                    buffer_id: excerpt.buffer_id,
2728                                    hunk_info,
2729                                    has_trailing_newline,
2730                                },
2731                                (),
2732                            );
2733                        }
2734
2735                        if !hunk_buffer_range.is_empty() {
2736                            *end_of_current_insert =
2737                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2738                        }
2739                    }
2740                }
2741            }
2742
2743            if excerpts.end() <= edit.new.end {
2744                excerpts.next();
2745            } else {
2746                break;
2747            }
2748        }
2749
2750        did_expand_hunks || !old_expanded_hunks.is_empty()
2751    }
2752
2753    fn append_diff_transforms(
2754        new_transforms: &mut SumTree<DiffTransform>,
2755        subtree: SumTree<DiffTransform>,
2756    ) {
2757        if let Some(DiffTransform::BufferContent {
2758            inserted_hunk_info,
2759            summary,
2760        }) = subtree.first()
2761            && Self::extend_last_buffer_content_transform(
2762                new_transforms,
2763                *inserted_hunk_info,
2764                *summary,
2765            )
2766        {
2767            let mut cursor = subtree.cursor::<()>(());
2768            cursor.next();
2769            cursor.next();
2770            new_transforms.append(cursor.suffix(), ());
2771            return;
2772        }
2773        new_transforms.append(subtree, ());
2774    }
2775
2776    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
2777        if let DiffTransform::BufferContent {
2778            inserted_hunk_info: inserted_hunk_anchor,
2779            summary,
2780        } = transform
2781            && Self::extend_last_buffer_content_transform(
2782                new_transforms,
2783                inserted_hunk_anchor,
2784                summary,
2785            )
2786        {
2787            return;
2788        }
2789        new_transforms.push(transform, ());
2790    }
2791
2792    fn push_buffer_content_transform(
2793        old_snapshot: &MultiBufferSnapshot,
2794        new_transforms: &mut SumTree<DiffTransform>,
2795        end_offset: ExcerptOffset,
2796        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2797    ) {
2798        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
2799            (end_offset.min(insertion_end_offset), Some(hunk_info))
2800        });
2801        let unchanged_region = [(end_offset, None)];
2802
2803        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
2804        {
2805            let start_offset = new_transforms.summary().excerpt_len();
2806            if end_offset <= start_offset {
2807                continue;
2808            }
2809            let summary_to_add = old_snapshot
2810                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2811
2812            if !Self::extend_last_buffer_content_transform(
2813                new_transforms,
2814                inserted_hunk_info,
2815                summary_to_add,
2816            ) {
2817                new_transforms.push(
2818                    DiffTransform::BufferContent {
2819                        summary: summary_to_add,
2820                        inserted_hunk_info,
2821                    },
2822                    (),
2823                )
2824            }
2825        }
2826    }
2827
2828    fn extend_last_buffer_content_transform(
2829        new_transforms: &mut SumTree<DiffTransform>,
2830        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
2831        summary_to_add: TextSummary,
2832    ) -> bool {
2833        let mut did_extend = false;
2834        new_transforms.update_last(
2835            |last_transform| {
2836                if let DiffTransform::BufferContent {
2837                    summary,
2838                    inserted_hunk_info: inserted_hunk_anchor,
2839                } = last_transform
2840                    && *inserted_hunk_anchor == new_inserted_hunk_info
2841                {
2842                    *summary += summary_to_add;
2843                    did_extend = true;
2844                }
2845            },
2846            (),
2847        );
2848        did_extend
2849    }
2850}
2851
2852fn build_excerpt_ranges(
2853    ranges: impl IntoIterator<Item = Range<Point>>,
2854    context_line_count: u32,
2855    buffer_snapshot: &BufferSnapshot,
2856) -> Vec<ExcerptRange<Point>> {
2857    ranges
2858        .into_iter()
2859        .map(|range| {
2860            let start_row = range.start.row.saturating_sub(context_line_count);
2861            let start = Point::new(start_row, 0);
2862            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
2863            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
2864            ExcerptRange {
2865                context: start..end,
2866                primary: range,
2867            }
2868        })
2869        .collect()
2870}
2871
2872#[cfg(any(test, feature = "test-support"))]
2873impl MultiBuffer {
2874    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2875        let buffer = cx.new(|cx| Buffer::local(text, cx));
2876        cx.new(|cx| Self::singleton(buffer, cx))
2877    }
2878
2879    pub fn build_multi<const COUNT: usize>(
2880        excerpts: [(&str, Vec<Range<Point>>); COUNT],
2881        cx: &mut gpui::App,
2882    ) -> Entity<Self> {
2883        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
2884        for (text, ranges) in excerpts {
2885            let buffer = cx.new(|cx| Buffer::local(text, cx));
2886            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
2887            multi.update(cx, |multi, cx| {
2888                multi.push_excerpts(buffer, excerpt_ranges, cx)
2889            });
2890        }
2891
2892        multi
2893    }
2894
2895    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
2896        cx.new(|cx| Self::singleton(buffer, cx))
2897    }
2898
2899    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
2900        cx.new(|cx| {
2901            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
2902            let mutation_count = rng.random_range(1..=5);
2903            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
2904            multibuffer
2905        })
2906    }
2907
2908    pub fn randomly_edit(
2909        &mut self,
2910        rng: &mut impl rand::Rng,
2911        edit_count: usize,
2912        cx: &mut Context<Self>,
2913    ) {
2914        use util::RandomCharIter;
2915
2916        let snapshot = self.read(cx);
2917        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
2918        let mut last_end = None;
2919        for _ in 0..edit_count {
2920            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
2921                break;
2922            }
2923
2924            let new_start = last_end.map_or(0, |last_end| last_end + 1);
2925            let end =
2926                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
2927            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
2928            last_end = Some(end);
2929
2930            let mut range = start..end;
2931            if rng.random_bool(0.2) {
2932                mem::swap(&mut range.start, &mut range.end);
2933            }
2934
2935            let new_text_len = rng.random_range(0..10);
2936            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
2937
2938            edits.push((range, new_text.into()));
2939        }
2940        log::info!("mutating multi-buffer with {:?}", edits);
2941        drop(snapshot);
2942
2943        self.edit(edits, None, cx);
2944    }
2945
2946    pub fn randomly_edit_excerpts(
2947        &mut self,
2948        rng: &mut impl rand::Rng,
2949        mutation_count: usize,
2950        cx: &mut Context<Self>,
2951    ) {
2952        use rand::prelude::*;
2953        use std::env;
2954        use util::RandomCharIter;
2955
2956        let max_excerpts = env::var("MAX_EXCERPTS")
2957            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
2958            .unwrap_or(5);
2959
2960        let mut buffers = Vec::new();
2961        for _ in 0..mutation_count {
2962            if rng.random_bool(0.05) {
2963                log::info!("Clearing multi-buffer");
2964                self.clear(cx);
2965                continue;
2966            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
2967                let ids = self.excerpt_ids();
2968                let mut excerpts = HashSet::default();
2969                for _ in 0..rng.random_range(0..ids.len()) {
2970                    excerpts.extend(ids.choose(rng).copied());
2971                }
2972
2973                let line_count = rng.random_range(0..5);
2974
2975                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
2976
2977                self.expand_excerpts(
2978                    excerpts.iter().cloned(),
2979                    line_count,
2980                    ExpandExcerptDirection::UpAndDown,
2981                    cx,
2982                );
2983                continue;
2984            }
2985
2986            let excerpt_ids = self.excerpt_ids();
2987            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
2988                let buffer_handle = if rng.random() || self.buffers.is_empty() {
2989                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
2990                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
2991                    let buffer = buffers.last().unwrap().read(cx);
2992                    log::info!(
2993                        "Creating new buffer {} with text: {:?}",
2994                        buffer.remote_id(),
2995                        buffer.text()
2996                    );
2997                    buffers.last().unwrap().clone()
2998                } else {
2999                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3000                };
3001
3002                let buffer = buffer_handle.read(cx);
3003                let buffer_text = buffer.text();
3004                let ranges = (0..rng.random_range(0..5))
3005                    .map(|_| {
3006                        let end_ix =
3007                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3008                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3009                        ExcerptRange::new(start_ix..end_ix)
3010                    })
3011                    .collect::<Vec<_>>();
3012                log::info!(
3013                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3014                    buffer_handle.read(cx).remote_id(),
3015                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3016                    ranges
3017                        .iter()
3018                        .map(|r| &buffer_text[r.context.clone()])
3019                        .collect::<Vec<_>>()
3020                );
3021
3022                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3023                log::info!("Inserted with ids: {:?}", excerpt_id);
3024            } else {
3025                let remove_count = rng.random_range(1..=excerpt_ids.len());
3026                let mut excerpts_to_remove = excerpt_ids
3027                    .choose_multiple(rng, remove_count)
3028                    .cloned()
3029                    .collect::<Vec<_>>();
3030                let snapshot = self.snapshot.borrow();
3031                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3032                drop(snapshot);
3033                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3034                self.remove_excerpts(excerpts_to_remove, cx);
3035            }
3036        }
3037    }
3038
3039    pub fn randomly_mutate(
3040        &mut self,
3041        rng: &mut impl rand::Rng,
3042        mutation_count: usize,
3043        cx: &mut Context<Self>,
3044    ) {
3045        use rand::prelude::*;
3046
3047        if rng.random_bool(0.7) || self.singleton {
3048            let buffer = self
3049                .buffers
3050                .values()
3051                .choose(rng)
3052                .map(|state| state.buffer.clone());
3053
3054            if let Some(buffer) = buffer {
3055                buffer.update(cx, |buffer, cx| {
3056                    if rng.random() {
3057                        buffer.randomly_edit(rng, mutation_count, cx);
3058                    } else {
3059                        buffer.randomly_undo_redo(rng, cx);
3060                    }
3061                });
3062            } else {
3063                self.randomly_edit(rng, mutation_count, cx);
3064            }
3065        } else {
3066            self.randomly_edit_excerpts(rng, mutation_count, cx);
3067        }
3068
3069        self.check_invariants(cx);
3070    }
3071
3072    fn check_invariants(&self, cx: &App) {
3073        self.read(cx).check_invariants();
3074    }
3075}
3076
3077impl EventEmitter<Event> for MultiBuffer {}
3078
3079impl MultiBufferSnapshot {
3080    pub fn text(&self) -> String {
3081        self.chunks(0..self.len(), false)
3082            .map(|chunk| chunk.text)
3083            .collect()
3084    }
3085
3086    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3087        self.reversed_chunks_in_range(0..position.to_offset(self))
3088            .flat_map(|c| c.chars().rev())
3089    }
3090
3091    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3092        let mut cursor = self.cursor::<usize>();
3093        cursor.seek(&range.end);
3094        let current_chunks = cursor.region().as_ref().map(|region| {
3095            let start_overshoot = range.start.saturating_sub(region.range.start);
3096            let end_overshoot = range.end - region.range.start;
3097            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3098            let start = region.buffer_range.start + start_overshoot;
3099            region.buffer.reversed_chunks_in_range(start..end)
3100        });
3101        ReversedMultiBufferChunks {
3102            cursor,
3103            current_chunks,
3104            start: range.start,
3105            offset: range.end,
3106        }
3107    }
3108
3109    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3110        let offset = position.to_offset(self);
3111        self.text_for_range(offset..self.len())
3112            .flat_map(|chunk| chunk.chars())
3113    }
3114
3115    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3116        self.chunks(range, false).map(|chunk| chunk.text)
3117    }
3118
3119    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3120        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3121            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3122    }
3123
3124    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3125    where
3126        T: ToOffset,
3127    {
3128        let position = position.to_offset(self);
3129        position == self.clip_offset(position, Bias::Left)
3130            && self
3131                .bytes_in_range(position..self.len())
3132                .flatten()
3133                .copied()
3134                .take(needle.len())
3135                .eq(needle.bytes())
3136    }
3137
3138    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3139        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3140    }
3141
3142    pub fn diff_hunks_in_range<T: ToPoint>(
3143        &self,
3144        range: Range<T>,
3145    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3146        let query_range = range.start.to_point(self)..range.end.to_point(self);
3147        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3148            let diff = self.diffs.get(&buffer.remote_id())?;
3149            let buffer_start = buffer.anchor_before(buffer_range.start);
3150            let buffer_end = buffer.anchor_after(buffer_range.end);
3151            Some(
3152                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3153                    .filter_map(|hunk| {
3154                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3155                            return None;
3156                        }
3157                        Some((hunk.range.clone(), hunk))
3158                    }),
3159            )
3160        })
3161        .filter_map(move |(range, hunk, excerpt)| {
3162            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3163            {
3164                return None;
3165            }
3166            let end_row = if range.end.column == 0 {
3167                range.end.row
3168            } else {
3169                range.end.row + 1
3170            };
3171            Some(MultiBufferDiffHunk {
3172                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3173                buffer_id: excerpt.buffer_id,
3174                excerpt_id: excerpt.id,
3175                buffer_range: hunk.buffer_range.clone(),
3176                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3177                secondary_status: hunk.secondary_status,
3178            })
3179        })
3180    }
3181
3182    pub fn excerpt_ids_for_range<T: ToOffset>(
3183        &self,
3184        range: Range<T>,
3185    ) -> impl Iterator<Item = ExcerptId> + '_ {
3186        let range = range.start.to_offset(self)..range.end.to_offset(self);
3187        let mut cursor = self.cursor::<usize>();
3188        cursor.seek(&range.start);
3189        std::iter::from_fn(move || {
3190            let region = cursor.region()?;
3191            if region.range.start >= range.end {
3192                return None;
3193            }
3194            cursor.next_excerpt();
3195            Some(region.excerpt.id)
3196        })
3197    }
3198
3199    pub fn buffer_ids_for_range<T: ToOffset>(
3200        &self,
3201        range: Range<T>,
3202    ) -> impl Iterator<Item = BufferId> + '_ {
3203        let range = range.start.to_offset(self)..range.end.to_offset(self);
3204        let mut cursor = self.cursor::<usize>();
3205        cursor.seek(&range.start);
3206        std::iter::from_fn(move || {
3207            let region = cursor.region()?;
3208            if region.range.start > range.end
3209                || region.range.start == range.end && region.range.start > range.start
3210            {
3211                return None;
3212            }
3213            cursor.next_excerpt();
3214            Some(region.excerpt.buffer_id)
3215        })
3216    }
3217
3218    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3219        &self,
3220        ranges: impl Iterator<Item = Range<T>>,
3221    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3222        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3223    }
3224
3225    pub fn range_to_buffer_ranges<T: ToOffset>(
3226        &self,
3227        range: Range<T>,
3228    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3229        let start = range.start.to_offset(self);
3230        let end = range.end.to_offset(self);
3231
3232        let mut cursor = self.cursor::<usize>();
3233        cursor.seek(&start);
3234
3235        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3236        while let Some(region) = cursor.region() {
3237            if region.range.start > end {
3238                break;
3239            }
3240            if region.is_main_buffer {
3241                let start_overshoot = start.saturating_sub(region.range.start);
3242                let end_overshoot = end.saturating_sub(region.range.start);
3243                let start = region
3244                    .buffer_range
3245                    .end
3246                    .min(region.buffer_range.start + start_overshoot);
3247                let end = region
3248                    .buffer_range
3249                    .end
3250                    .min(region.buffer_range.start + end_overshoot);
3251                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3252                    *excerpt_id == region.excerpt.id && prev_range.end == start
3253                }) {
3254                    prev.1.end = end;
3255                } else {
3256                    result.push((region.buffer, start..end, region.excerpt.id));
3257                }
3258            }
3259            cursor.next();
3260        }
3261        result
3262    }
3263
3264    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3265        &self,
3266        range: Range<T>,
3267    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3268        let start = range.start.to_offset(self);
3269        let end = range.end.to_offset(self);
3270
3271        let mut cursor = self.cursor::<usize>();
3272        cursor.seek(&start);
3273
3274        std::iter::from_fn(move || {
3275            let region = cursor.region()?;
3276            if region.range.start > end {
3277                return None;
3278            }
3279            let start_overshoot = start.saturating_sub(region.range.start);
3280            let end_overshoot = end.saturating_sub(region.range.start);
3281            let start = region
3282                .buffer_range
3283                .end
3284                .min(region.buffer_range.start + start_overshoot);
3285            let end = region
3286                .buffer_range
3287                .end
3288                .min(region.buffer_range.start + end_overshoot);
3289
3290            let region_excerpt_id = region.excerpt.id;
3291            let deleted_hunk_anchor = if region.is_main_buffer {
3292                None
3293            } else {
3294                Some(self.anchor_before(region.range.start))
3295            };
3296            let result = (
3297                region.buffer,
3298                start..end,
3299                region_excerpt_id,
3300                deleted_hunk_anchor,
3301            );
3302            cursor.next();
3303            Some(result)
3304        })
3305    }
3306
3307    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3308    /// coordinates.
3309    ///
3310    /// The given callback will be called for every excerpt intersecting the given range. It will
3311    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3312    /// The callback should return an iterator of metadata items from that buffer, each paired
3313    /// with a buffer range.
3314    ///
3315    /// The returned iterator yields each of these metadata items, paired with its range in
3316    /// multi-buffer coordinates.
3317    fn lift_buffer_metadata<'a, D, M, I>(
3318        &'a self,
3319        query_range: Range<D>,
3320        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3321    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3322    where
3323        I: Iterator<Item = (Range<D>, M)> + 'a,
3324        D: TextDimension + Ord + Sub<D, Output = D>,
3325    {
3326        let max_position = D::from_text_summary(&self.text_summary());
3327        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3328        let mut cursor = self.cursor::<D>();
3329
3330        // Find the excerpt and buffer offset where the given range ends.
3331        cursor.seek(&query_range.end);
3332        let mut range_end = None;
3333        while let Some(region) = cursor.region() {
3334            if region.is_main_buffer {
3335                let mut buffer_end = region.buffer_range.start;
3336                let overshoot = if query_range.end > region.range.start {
3337                    query_range.end - region.range.start
3338                } else {
3339                    D::default()
3340                };
3341                buffer_end.add_assign(&overshoot);
3342                range_end = Some((region.excerpt.id, buffer_end));
3343                break;
3344            }
3345            cursor.next();
3346        }
3347
3348        cursor.seek(&query_range.start);
3349
3350        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3351            && region.range.start > D::zero(())
3352        {
3353            cursor.prev()
3354        }
3355
3356        iter::from_fn(move || {
3357            loop {
3358                let excerpt = cursor.excerpt()?;
3359
3360                // If we have already retrieved metadata for this excerpt, continue to use it.
3361                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3362                    .as_mut()
3363                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3364                {
3365                    Some(metadata)
3366                }
3367                // Otherwise, compute the intersection of the input range with the excerpt's range,
3368                // and retrieve the metadata for the resulting range.
3369                else {
3370                    let region = cursor.region()?;
3371                    let mut buffer_start;
3372                    if region.is_main_buffer {
3373                        buffer_start = region.buffer_range.start;
3374                        if query_range.start > region.range.start {
3375                            let overshoot = query_range.start - region.range.start;
3376                            buffer_start.add_assign(&overshoot);
3377                        }
3378                        buffer_start = buffer_start.min(region.buffer_range.end);
3379                    } else {
3380                        buffer_start = cursor.main_buffer_position()?;
3381                    };
3382                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3383                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
3384                        && excerpt.id == end_excerpt_id
3385                    {
3386                        buffer_end = buffer_end.min(end_buffer_offset);
3387                    }
3388
3389                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
3390                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
3391                    })
3392                };
3393
3394                // Visit each metadata item.
3395                if let Some((metadata_buffer_range, metadata)) =
3396                    metadata_iter.and_then(Iterator::next)
3397                {
3398                    // Find the multibuffer regions that contain the start and end of
3399                    // the metadata item's range.
3400                    if metadata_buffer_range.start > D::default() {
3401                        while let Some(region) = cursor.region() {
3402                            if region.is_main_buffer
3403                                && (region.buffer_range.end >= metadata_buffer_range.start
3404                                    || cursor.is_at_end_of_excerpt())
3405                            {
3406                                break;
3407                            }
3408                            cursor.next();
3409                        }
3410                    }
3411                    let start_region = cursor.region()?;
3412                    while let Some(region) = cursor.region() {
3413                        if region.is_main_buffer
3414                            && (region.buffer_range.end > metadata_buffer_range.end
3415                                || cursor.is_at_end_of_excerpt())
3416                        {
3417                            break;
3418                        }
3419                        cursor.next();
3420                    }
3421                    let end_region = cursor.region();
3422
3423                    // Convert the metadata item's range into multibuffer coordinates.
3424                    let mut start_position = start_region.range.start;
3425                    let region_buffer_start = start_region.buffer_range.start;
3426                    if start_region.is_main_buffer
3427                        && metadata_buffer_range.start > region_buffer_start
3428                    {
3429                        start_position
3430                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
3431                        start_position = start_position.min(start_region.range.end);
3432                    }
3433
3434                    let mut end_position = max_position;
3435                    if let Some(end_region) = &end_region {
3436                        end_position = end_region.range.start;
3437                        debug_assert!(end_region.is_main_buffer);
3438                        let region_buffer_start = end_region.buffer_range.start;
3439                        if metadata_buffer_range.end > region_buffer_start {
3440                            end_position
3441                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
3442                        }
3443                        end_position = end_position.min(end_region.range.end);
3444                    }
3445
3446                    if start_position <= query_range.end && end_position >= query_range.start {
3447                        return Some((start_position..end_position, metadata, excerpt));
3448                    }
3449                }
3450                // When there are no more metadata items for this excerpt, move to the next excerpt.
3451                else {
3452                    current_excerpt_metadata.take();
3453                    if let Some((end_excerpt_id, _)) = range_end
3454                        && excerpt.id == end_excerpt_id
3455                    {
3456                        return None;
3457                    }
3458                    cursor.next_excerpt();
3459                }
3460            }
3461        })
3462    }
3463
3464    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3465        let offset = position.to_offset(self);
3466
3467        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3468        cursor.seek(&DimensionPair {
3469            key: offset,
3470            value: None,
3471        });
3472        cursor.seek_to_start_of_current_excerpt();
3473        let excerpt = cursor.excerpt()?;
3474
3475        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3476        let current_position = self
3477            .anchor_before(offset)
3478            .text_anchor
3479            .to_offset(&excerpt.buffer);
3480        let excerpt_end = excerpt
3481            .buffer
3482            .anchor_before(excerpt_end.min(current_position));
3483
3484        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3485            for hunk in diff.hunks_intersecting_range_rev(
3486                excerpt.range.context.start..excerpt_end,
3487                &excerpt.buffer,
3488            ) {
3489                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3490                if hunk_end >= current_position {
3491                    continue;
3492                }
3493                let start =
3494                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3495                        .to_point(self);
3496                return Some(MultiBufferRow(start.row));
3497            }
3498        }
3499
3500        loop {
3501            cursor.prev_excerpt();
3502            let excerpt = cursor.excerpt()?;
3503
3504            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3505                continue;
3506            };
3507            let mut hunks =
3508                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3509            let Some(hunk) = hunks.next() else {
3510                continue;
3511            };
3512            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3513                .to_point(self);
3514            return Some(MultiBufferRow(start.row));
3515        }
3516    }
3517
3518    pub fn has_diff_hunks(&self) -> bool {
3519        self.diffs.values().any(|diff| !diff.is_empty())
3520    }
3521
3522    pub fn is_inside_word<T: ToOffset>(
3523        &self,
3524        position: T,
3525        scope_context: Option<CharScopeContext>,
3526    ) -> bool {
3527        let position = position.to_offset(self);
3528        let classifier = self
3529            .char_classifier_at(position)
3530            .scope_context(scope_context);
3531        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
3532        let prev_char_kind = self
3533            .reversed_chars_at(position)
3534            .next()
3535            .map(|c| classifier.kind(c));
3536        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
3537    }
3538
3539    pub fn surrounding_word<T: ToOffset>(
3540        &self,
3541        start: T,
3542        scope_context: Option<CharScopeContext>,
3543    ) -> (Range<usize>, Option<CharKind>) {
3544        let mut start = start.to_offset(self);
3545        let mut end = start;
3546        let mut next_chars = self.chars_at(start).peekable();
3547        let mut prev_chars = self.reversed_chars_at(start).peekable();
3548
3549        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3550
3551        let word_kind = cmp::max(
3552            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3553            next_chars.peek().copied().map(|c| classifier.kind(c)),
3554        );
3555
3556        for ch in prev_chars {
3557            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3558                start -= ch.len_utf8();
3559            } else {
3560                break;
3561            }
3562        }
3563
3564        for ch in next_chars {
3565            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3566                end += ch.len_utf8();
3567            } else {
3568                break;
3569            }
3570        }
3571
3572        (start..end, word_kind)
3573    }
3574
3575    pub fn char_kind_before<T: ToOffset>(
3576        &self,
3577        start: T,
3578        scope_context: Option<CharScopeContext>,
3579    ) -> Option<CharKind> {
3580        let start = start.to_offset(self);
3581        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3582        self.reversed_chars_at(start)
3583            .next()
3584            .map(|ch| classifier.kind(ch))
3585    }
3586
3587    pub fn is_singleton(&self) -> bool {
3588        self.singleton
3589    }
3590
3591    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3592        if self.singleton {
3593            self.excerpts
3594                .iter()
3595                .next()
3596                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3597        } else {
3598            None
3599        }
3600    }
3601
3602    pub fn len(&self) -> usize {
3603        self.diff_transforms.summary().output.len
3604    }
3605
3606    pub fn is_empty(&self) -> bool {
3607        self.excerpts.summary().text.len == 0
3608    }
3609
3610    pub fn widest_line_number(&self) -> u32 {
3611        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
3612        self.excerpts.summary().widest_line_number + 1
3613    }
3614
3615    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
3616        let range = range.start.to_offset(self)..range.end.to_offset(self);
3617        let mut excerpts = self.cursor::<usize>();
3618        excerpts.seek(&range.start);
3619
3620        let mut chunk;
3621        let mut has_trailing_newline;
3622        let excerpt_bytes;
3623        if let Some(region) = excerpts.region() {
3624            let mut bytes = region.buffer.bytes_in_range(
3625                region.buffer_range.start + range.start - region.range.start
3626                    ..(region.buffer_range.start + range.end - region.range.start)
3627                        .min(region.buffer_range.end),
3628            );
3629            chunk = bytes.next().unwrap_or(&[][..]);
3630            excerpt_bytes = Some(bytes);
3631            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3632            if chunk.is_empty() && has_trailing_newline {
3633                chunk = b"\n";
3634                has_trailing_newline = false;
3635            }
3636        } else {
3637            chunk = &[][..];
3638            excerpt_bytes = None;
3639            has_trailing_newline = false;
3640        };
3641
3642        MultiBufferBytes {
3643            range,
3644            cursor: excerpts,
3645            excerpt_bytes,
3646            has_trailing_newline,
3647            chunk,
3648        }
3649    }
3650
3651    pub fn reversed_bytes_in_range<T: ToOffset>(
3652        &self,
3653        range: Range<T>,
3654    ) -> ReversedMultiBufferBytes<'_> {
3655        let range = range.start.to_offset(self)..range.end.to_offset(self);
3656        let mut chunks = self.reversed_chunks_in_range(range.clone());
3657        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3658        ReversedMultiBufferBytes {
3659            range,
3660            chunks,
3661            chunk,
3662        }
3663    }
3664
3665    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
3666        let mut cursor = self.cursor::<Point>();
3667        cursor.seek(&Point::new(start_row.0, 0));
3668        let mut result = MultiBufferRows {
3669            point: Point::new(0, 0),
3670            is_empty: self.excerpts.is_empty(),
3671            is_singleton: self.is_singleton(),
3672            cursor,
3673        };
3674        result.seek(start_row);
3675        result
3676    }
3677
3678    pub fn chunks<T: ToOffset>(
3679        &self,
3680        range: Range<T>,
3681        language_aware: bool,
3682    ) -> MultiBufferChunks<'_> {
3683        let mut chunks = MultiBufferChunks {
3684            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3685            range: 0..0,
3686            excerpts: self.excerpts.cursor(()),
3687            diff_transforms: self.diff_transforms.cursor(()),
3688            diffs: &self.diffs,
3689            diff_base_chunks: None,
3690            excerpt_chunks: None,
3691            buffer_chunk: None,
3692            language_aware,
3693        };
3694        let range = range.start.to_offset(self)..range.end.to_offset(self);
3695        chunks.seek(range);
3696        chunks
3697    }
3698
3699    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3700        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3701    }
3702
3703    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3704        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3705    }
3706
3707    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3708        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3709    }
3710
3711    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3712        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3713            buffer.clip_point_utf16(Unclipped(point), bias)
3714        })
3715    }
3716
3717    pub fn offset_to_point(&self, offset: usize) -> Point {
3718        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3719    }
3720
3721    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3722        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3723    }
3724
3725    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3726        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3727    }
3728
3729    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
3730        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
3731    }
3732
3733    pub fn point_to_offset(&self, point: Point) -> usize {
3734        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3735    }
3736
3737    pub fn point_to_offset_utf16(&self, point: Point) -> OffsetUtf16 {
3738        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
3739    }
3740
3741    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3742        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3743    }
3744
3745    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3746        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3747    }
3748
3749    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3750        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3751    }
3752
3753    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> OffsetUtf16 {
3754        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
3755    }
3756
3757    fn clip_dimension<D>(
3758        &self,
3759        position: D,
3760        bias: Bias,
3761        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3762    ) -> D
3763    where
3764        D: TextDimension + Ord + Sub<D, Output = D>,
3765    {
3766        let mut cursor = self.cursor();
3767        cursor.seek(&position);
3768        if let Some(region) = cursor.region() {
3769            if position >= region.range.end {
3770                return region.range.end;
3771            }
3772            let overshoot = position - region.range.start;
3773            let mut buffer_position = region.buffer_range.start;
3774            buffer_position.add_assign(&overshoot);
3775            let clipped_buffer_position =
3776                clip_buffer_position(region.buffer, buffer_position, bias);
3777            let mut position = region.range.start;
3778            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3779            position
3780        } else {
3781            D::from_text_summary(&self.text_summary())
3782        }
3783    }
3784
3785    fn convert_dimension<D1, D2>(
3786        &self,
3787        key: D1,
3788        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3789    ) -> D2
3790    where
3791        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3792        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3793    {
3794        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3795        cursor.seek(&DimensionPair { key, value: None });
3796        if let Some(region) = cursor.region() {
3797            if key >= region.range.end.key {
3798                return region.range.end.value.unwrap();
3799            }
3800            let start_key = region.range.start.key;
3801            let start_value = region.range.start.value.unwrap();
3802            let buffer_start_key = region.buffer_range.start.key;
3803            let buffer_start_value = region.buffer_range.start.value.unwrap();
3804            let mut buffer_key = buffer_start_key;
3805            buffer_key.add_assign(&(key - start_key));
3806            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
3807            let mut result = start_value;
3808            result.add_assign(&(buffer_value - buffer_start_value));
3809            result
3810        } else {
3811            D2::from_text_summary(&self.text_summary())
3812        }
3813    }
3814
3815    pub fn point_to_buffer_offset<T: ToOffset>(
3816        &self,
3817        point: T,
3818    ) -> Option<(&BufferSnapshot, usize)> {
3819        let offset = point.to_offset(self);
3820        let mut cursor = self.cursor::<usize>();
3821        cursor.seek(&offset);
3822        let region = cursor.region()?;
3823        let overshoot = offset - region.range.start;
3824        let buffer_offset = region.buffer_range.start + overshoot;
3825        if buffer_offset == region.buffer.len() + 1
3826            && region.has_trailing_newline
3827            && !region.is_main_buffer
3828        {
3829            let main_buffer_position = cursor.main_buffer_position()?;
3830            let buffer_snapshot = &cursor.excerpt()?.buffer;
3831            return Some((buffer_snapshot, main_buffer_position));
3832        } else if buffer_offset > region.buffer.len() {
3833            return None;
3834        }
3835        Some((region.buffer, buffer_offset))
3836    }
3837
3838    pub fn point_to_buffer_point(
3839        &self,
3840        point: Point,
3841    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
3842        let mut cursor = self.cursor::<Point>();
3843        cursor.seek(&point);
3844        let region = cursor.region()?;
3845        let overshoot = point - region.range.start;
3846        let buffer_point = region.buffer_range.start + overshoot;
3847        let excerpt = cursor.excerpt()?;
3848        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
3849            && region.has_trailing_newline
3850            && !region.is_main_buffer
3851        {
3852            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
3853        } else if buffer_point > region.buffer.max_point() {
3854            return None;
3855        }
3856        Some((region.buffer, buffer_point, excerpt.id))
3857    }
3858
3859    pub fn suggested_indents(
3860        &self,
3861        rows: impl IntoIterator<Item = u32>,
3862        cx: &App,
3863    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3864        let mut result = BTreeMap::new();
3865
3866        let mut rows_for_excerpt = Vec::new();
3867        let mut cursor = self.cursor::<Point>();
3868        let mut rows = rows.into_iter().peekable();
3869        let mut prev_row = u32::MAX;
3870        let mut prev_language_indent_size = IndentSize::default();
3871
3872        while let Some(row) = rows.next() {
3873            cursor.seek(&Point::new(row, 0));
3874            let Some(region) = cursor.region() else {
3875                continue;
3876            };
3877
3878            // Retrieve the language and indent size once for each disjoint region being indented.
3879            let single_indent_size = if row.saturating_sub(1) == prev_row {
3880                prev_language_indent_size
3881            } else {
3882                region
3883                    .buffer
3884                    .language_indent_size_at(Point::new(row, 0), cx)
3885            };
3886            prev_language_indent_size = single_indent_size;
3887            prev_row = row;
3888
3889            let start_buffer_row = region.buffer_range.start.row;
3890            let start_multibuffer_row = region.range.start.row;
3891            let end_multibuffer_row = region.range.end.row;
3892
3893            rows_for_excerpt.push(row);
3894            while let Some(next_row) = rows.peek().copied() {
3895                if end_multibuffer_row > next_row {
3896                    rows_for_excerpt.push(next_row);
3897                    rows.next();
3898                } else {
3899                    break;
3900                }
3901            }
3902
3903            let buffer_rows = rows_for_excerpt
3904                .drain(..)
3905                .map(|row| start_buffer_row + row - start_multibuffer_row);
3906            let buffer_indents = region
3907                .buffer
3908                .suggested_indents(buffer_rows, single_indent_size);
3909            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
3910                (
3911                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
3912                    indent,
3913                )
3914            });
3915            result.extend(multibuffer_indents);
3916        }
3917
3918        result
3919    }
3920
3921    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
3922        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3923            let mut size = buffer.indent_size_for_line(range.start.row);
3924            size.len = size
3925                .len
3926                .min(range.end.column)
3927                .saturating_sub(range.start.column);
3928            size
3929        } else {
3930            IndentSize::spaces(0)
3931        }
3932    }
3933
3934    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
3935        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3936            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
3937        } else {
3938            LineIndent::spaces(0)
3939        }
3940    }
3941
3942    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
3943        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
3944
3945        if self.language_settings(cx).extend_comment_on_newline
3946            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
3947        {
3948            let delimiters = language_scope.line_comment_prefixes();
3949            for delimiter in delimiters {
3950                if *self
3951                    .chars_at(Point::new(row.0, indent.len() as u32))
3952                    .take(delimiter.chars().count())
3953                    .collect::<String>()
3954                    .as_str()
3955                    == **delimiter
3956                {
3957                    indent.push_str(delimiter);
3958                    break;
3959                }
3960            }
3961        }
3962
3963        indent
3964    }
3965
3966    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
3967    where
3968        T: ToOffset,
3969    {
3970        for char in self.reversed_chars_at(position) {
3971            if !char.is_whitespace() {
3972                return false;
3973            }
3974            if char == '\n' {
3975                return true;
3976            }
3977        }
3978        true
3979    }
3980
3981    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
3982        while row.0 > 0 {
3983            row.0 -= 1;
3984            if !self.is_line_blank(row) {
3985                return Some(row);
3986            }
3987        }
3988        None
3989    }
3990
3991    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
3992        if let Some((_, range)) = self.buffer_line_for_row(row) {
3993            range.end.column - range.start.column
3994        } else {
3995            0
3996        }
3997    }
3998
3999    pub fn buffer_line_for_row(
4000        &self,
4001        row: MultiBufferRow,
4002    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4003        let mut cursor = self.cursor::<Point>();
4004        let point = Point::new(row.0, 0);
4005        cursor.seek(&point);
4006        let region = cursor.region()?;
4007        let overshoot = point.min(region.range.end) - region.range.start;
4008        let buffer_point = region.buffer_range.start + overshoot;
4009        if buffer_point.row > region.buffer_range.end.row {
4010            return None;
4011        }
4012        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4013        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4014            .min(region.buffer_range.end);
4015        Some((region.buffer, line_start..line_end))
4016    }
4017
4018    pub fn max_point(&self) -> Point {
4019        self.text_summary().lines
4020    }
4021
4022    pub fn max_row(&self) -> MultiBufferRow {
4023        MultiBufferRow(self.text_summary().lines.row)
4024    }
4025
4026    pub fn text_summary(&self) -> TextSummary {
4027        self.diff_transforms.summary().output
4028    }
4029
4030    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4031    where
4032        D: TextDimension,
4033        O: ToOffset,
4034    {
4035        let range = range.start.to_offset(self)..range.end.to_offset(self);
4036        let mut cursor = self
4037            .diff_transforms
4038            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4039        cursor.seek(&range.start, Bias::Right);
4040
4041        let Some(first_transform) = cursor.item() else {
4042            return D::from_text_summary(&TextSummary::default());
4043        };
4044
4045        let diff_transform_start = cursor.start().0;
4046        let diff_transform_end = cursor.end().0;
4047        let diff_start = range.start;
4048        let start_overshoot = diff_start - diff_transform_start;
4049        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4050
4051        let mut result = match first_transform {
4052            DiffTransform::BufferContent { .. } => {
4053                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4054                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4055                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4056            }
4057            DiffTransform::DeletedHunk {
4058                buffer_id,
4059                base_text_byte_range,
4060                has_trailing_newline,
4061                ..
4062            } => {
4063                let buffer_start = base_text_byte_range.start + start_overshoot;
4064                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4065                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4066                    panic!("{:?} is in non-existent deleted hunk", range.start)
4067                };
4068
4069                let include_trailing_newline =
4070                    *has_trailing_newline && range.end >= diff_transform_end;
4071                if include_trailing_newline {
4072                    buffer_end -= 1;
4073                }
4074
4075                let mut summary =
4076                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4077
4078                if include_trailing_newline {
4079                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4080                }
4081
4082                summary
4083            }
4084        };
4085        if range.end < diff_transform_end {
4086            return result;
4087        }
4088
4089        cursor.next();
4090        result.add_assign(&D::from_text_summary(
4091            &cursor.summary(&range.end, Bias::Right),
4092        ));
4093
4094        let Some(last_transform) = cursor.item() else {
4095            return result;
4096        };
4097
4098        let overshoot = range.end - cursor.start().0;
4099        let suffix = match last_transform {
4100            DiffTransform::BufferContent { .. } => {
4101                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4102                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4103            }
4104            DiffTransform::DeletedHunk {
4105                base_text_byte_range,
4106                buffer_id,
4107                has_trailing_newline,
4108                ..
4109            } => {
4110                let buffer_end = base_text_byte_range.start + overshoot;
4111                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4112                    panic!("{:?} is in non-existent deleted hunk", range.end)
4113                };
4114
4115                let mut suffix = base_text
4116                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4117                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4118                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4119                }
4120                suffix
4121            }
4122        };
4123
4124        result.add_assign(&suffix);
4125        result
4126    }
4127
4128    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4129    where
4130        D: TextDimension,
4131    {
4132        let mut summary = D::zero(());
4133        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4134        cursor.seek(&range.start, Bias::Right);
4135        if let Some(excerpt) = cursor.item() {
4136            let mut end_before_newline = cursor.end();
4137            if excerpt.has_trailing_newline {
4138                end_before_newline -= ExcerptOffset::new(1);
4139            }
4140
4141            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4142            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4143            let end_in_excerpt =
4144                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4145            summary.add_assign(
4146                &excerpt
4147                    .buffer
4148                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4149            );
4150
4151            if range.end > end_before_newline {
4152                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4153            }
4154
4155            cursor.next();
4156        }
4157
4158        if range.end > *cursor.start() {
4159            summary.add_assign(
4160                &cursor
4161                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4162                    .0,
4163            );
4164            if let Some(excerpt) = cursor.item() {
4165                range.end = cmp::max(*cursor.start(), range.end);
4166
4167                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4168                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4169                summary.add_assign(
4170                    &excerpt
4171                        .buffer
4172                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4173                );
4174            }
4175        }
4176
4177        summary
4178    }
4179
4180    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4181    where
4182        D: TextDimension + Ord + Sub<D, Output = D>,
4183    {
4184        self.summaries_for_anchors([anchor])[0]
4185    }
4186
4187    fn resolve_summary_for_anchor<D>(
4188        &self,
4189        anchor: &Anchor,
4190        excerpt_position: D,
4191        diff_transforms: &mut Cursor<
4192            DiffTransform,
4193            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4194        >,
4195    ) -> D
4196    where
4197        D: TextDimension + Ord + Sub<D, Output = D>,
4198    {
4199        loop {
4200            let transform_end_position = diff_transforms.end().0.0;
4201            let at_transform_end =
4202                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4203            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4204                diff_transforms.next();
4205                continue;
4206            }
4207
4208            let mut position = diff_transforms.start().1.0;
4209            match diff_transforms.item() {
4210                Some(DiffTransform::DeletedHunk {
4211                    buffer_id,
4212                    base_text_byte_range,
4213                    ..
4214                }) => {
4215                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4216                        && let Some(base_text) =
4217                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4218                        && base_text.can_resolve(diff_base_anchor)
4219                    {
4220                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4221                        if base_text_offset >= base_text_byte_range.start
4222                            && base_text_offset <= base_text_byte_range.end
4223                        {
4224                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4225                                base_text_byte_range.start..base_text_offset,
4226                            );
4227                            position.add_assign(&position_in_hunk);
4228                        } else if at_transform_end {
4229                            diff_transforms.next();
4230                            continue;
4231                        }
4232                    }
4233                }
4234                _ => {
4235                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4236                        diff_transforms.next();
4237                        continue;
4238                    }
4239                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4240                    position.add_assign(&overshoot);
4241                }
4242            }
4243
4244            return position;
4245        }
4246    }
4247
4248    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4249        let mut cursor = self
4250            .excerpts
4251            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4252        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4253
4254        cursor.seek(&Some(locator), Bias::Left);
4255        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4256            cursor.prev();
4257        }
4258
4259        let mut position = cursor.start().1;
4260        if let Some(excerpt) = cursor.item()
4261            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4262        {
4263            let excerpt_buffer_start = excerpt
4264                .buffer
4265                .offset_for_anchor(&excerpt.range.context.start);
4266            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4267            let buffer_position = cmp::min(
4268                excerpt_buffer_end,
4269                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4270            );
4271            if buffer_position > excerpt_buffer_start {
4272                position.value += buffer_position - excerpt_buffer_start;
4273            }
4274        }
4275        position
4276    }
4277
4278    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4279        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4280            excerpt_id = *replacement;
4281        }
4282        excerpt_id
4283    }
4284
4285    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4286    where
4287        D: TextDimension + Ord + Sub<D, Output = D>,
4288        I: 'a + IntoIterator<Item = &'a Anchor>,
4289    {
4290        let mut anchors = anchors.into_iter().peekable();
4291        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4292        let mut diff_transforms_cursor = self
4293            .diff_transforms
4294            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(());
4295        diff_transforms_cursor.next();
4296
4297        let mut summaries = Vec::new();
4298        while let Some(anchor) = anchors.peek() {
4299            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4300
4301            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4302                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4303            });
4304
4305            let locator = self.excerpt_locator_for_id(excerpt_id);
4306            cursor.seek_forward(locator, Bias::Left);
4307            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4308                cursor.prev();
4309            }
4310
4311            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4312            if let Some(excerpt) = cursor.item() {
4313                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4314                    let position = self.resolve_summary_for_anchor(
4315                        &Anchor::min(),
4316                        excerpt_start_position,
4317                        &mut diff_transforms_cursor,
4318                    );
4319                    summaries.extend(excerpt_anchors.map(|_| position));
4320                    continue;
4321                }
4322                let excerpt_buffer_start =
4323                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4324                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4325                for (buffer_summary, anchor) in excerpt
4326                    .buffer
4327                    .summaries_for_anchors_with_payload::<D, _, _>(
4328                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4329                    )
4330                {
4331                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4332                    let mut position = excerpt_start_position;
4333                    if summary > excerpt_buffer_start {
4334                        position.add_assign(&(summary - excerpt_buffer_start));
4335                    }
4336
4337                    if position > diff_transforms_cursor.start().0.0 {
4338                        diff_transforms_cursor
4339                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4340                    }
4341
4342                    summaries.push(self.resolve_summary_for_anchor(
4343                        anchor,
4344                        position,
4345                        &mut diff_transforms_cursor,
4346                    ));
4347                }
4348            } else {
4349                diff_transforms_cursor
4350                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4351                let position = self.resolve_summary_for_anchor(
4352                    &Anchor::max(),
4353                    excerpt_start_position,
4354                    &mut diff_transforms_cursor,
4355                );
4356                summaries.extend(excerpt_anchors.map(|_| position));
4357            }
4358        }
4359
4360        summaries
4361    }
4362
4363    pub fn dimensions_from_points<'a, D>(
4364        &'a self,
4365        points: impl 'a + IntoIterator<Item = Point>,
4366    ) -> impl 'a + Iterator<Item = D>
4367    where
4368        D: TextDimension + Sub<D, Output = D>,
4369    {
4370        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4371        cursor.seek(&DimensionPair {
4372            key: Point::default(),
4373            value: None,
4374        });
4375        let mut points = points.into_iter();
4376        iter::from_fn(move || {
4377            let point = points.next()?;
4378
4379            cursor.seek_forward(&DimensionPair {
4380                key: point,
4381                value: None,
4382            });
4383
4384            if let Some(region) = cursor.region() {
4385                let overshoot = point - region.range.start.key;
4386                let buffer_point = region.buffer_range.start.key + overshoot;
4387                let mut position = region.range.start.value.unwrap();
4388                position.add_assign(
4389                    &region
4390                        .buffer
4391                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4392                );
4393                if point == region.range.end.key && region.has_trailing_newline {
4394                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4395                }
4396                Some(position)
4397            } else {
4398                Some(D::from_text_summary(&self.text_summary()))
4399            }
4400        })
4401    }
4402
4403    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4404    where
4405        I: 'a + IntoIterator<Item = &'a Anchor>,
4406    {
4407        let mut anchors = anchors.into_iter().enumerate().peekable();
4408        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4409        cursor.next();
4410
4411        let mut result = Vec::new();
4412
4413        while let Some((_, anchor)) = anchors.peek() {
4414            let old_excerpt_id = anchor.excerpt_id;
4415
4416            // Find the location where this anchor's excerpt should be.
4417            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4418            cursor.seek_forward(&Some(old_locator), Bias::Left);
4419
4420            let next_excerpt = cursor.item();
4421            let prev_excerpt = cursor.prev_item();
4422
4423            // Process all of the anchors for this excerpt.
4424            while let Some((anchor_ix, &anchor)) =
4425                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
4426            {
4427                let mut anchor = anchor;
4428
4429                // Leave min and max anchors unchanged if invalid or
4430                // if the old excerpt still exists at this location
4431                let mut kept_position = next_excerpt
4432                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
4433                    || old_excerpt_id == ExcerptId::max()
4434                    || old_excerpt_id == ExcerptId::min();
4435
4436                // If the old excerpt no longer exists at this location, then attempt to
4437                // find an equivalent position for this anchor in an adjacent excerpt.
4438                if !kept_position {
4439                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4440                        if excerpt.contains(&anchor) {
4441                            anchor.excerpt_id = excerpt.id;
4442                            kept_position = true;
4443                            break;
4444                        }
4445                    }
4446                }
4447
4448                // If there's no adjacent excerpt that contains the anchor's position,
4449                // then report that the anchor has lost its position.
4450                if !kept_position {
4451                    anchor = if let Some(excerpt) = next_excerpt {
4452                        let mut text_anchor = excerpt
4453                            .range
4454                            .context
4455                            .start
4456                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4457                        if text_anchor
4458                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4459                            .is_gt()
4460                        {
4461                            text_anchor = excerpt.range.context.end;
4462                        }
4463                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4464                    } else if let Some(excerpt) = prev_excerpt {
4465                        let mut text_anchor = excerpt
4466                            .range
4467                            .context
4468                            .end
4469                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4470                        if text_anchor
4471                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4472                            .is_lt()
4473                        {
4474                            text_anchor = excerpt.range.context.start;
4475                        }
4476                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4477                    } else if anchor.text_anchor.bias == Bias::Left {
4478                        Anchor::min()
4479                    } else {
4480                        Anchor::max()
4481                    };
4482                }
4483
4484                result.push((anchor_ix, anchor, kept_position));
4485            }
4486        }
4487        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4488        result
4489    }
4490
4491    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4492        self.anchor_at(position, Bias::Left)
4493    }
4494
4495    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4496        self.anchor_at(position, Bias::Right)
4497    }
4498
4499    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4500        let offset = position.to_offset(self);
4501
4502        // Find the given position in the diff transforms. Determine the corresponding
4503        // offset in the excerpts, and whether the position is within a deleted hunk.
4504        let mut diff_transforms = self
4505            .diff_transforms
4506            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4507        diff_transforms.seek(&offset, Bias::Right);
4508
4509        if offset == diff_transforms.start().0
4510            && bias == Bias::Left
4511            && let Some(prev_item) = diff_transforms.prev_item()
4512            && let DiffTransform::DeletedHunk { .. } = prev_item
4513        {
4514            diff_transforms.prev();
4515        }
4516        let offset_in_transform = offset - diff_transforms.start().0;
4517        let mut excerpt_offset = diff_transforms.start().1;
4518        let mut diff_base_anchor = None;
4519        if let Some(DiffTransform::DeletedHunk {
4520            buffer_id,
4521            base_text_byte_range,
4522            has_trailing_newline,
4523            ..
4524        }) = diff_transforms.item()
4525        {
4526            let diff = self.diffs.get(buffer_id).expect("missing diff");
4527            if offset_in_transform > base_text_byte_range.len() {
4528                debug_assert!(*has_trailing_newline);
4529                bias = Bias::Right;
4530            } else {
4531                diff_base_anchor = Some(
4532                    diff.base_text()
4533                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4534                );
4535                bias = Bias::Left;
4536            }
4537        } else {
4538            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4539        };
4540
4541        let mut excerpts = self
4542            .excerpts
4543            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
4544        excerpts.seek(&excerpt_offset, Bias::Right);
4545        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4546            excerpts.prev();
4547        }
4548        if let Some(excerpt) = excerpts.item() {
4549            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4550            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
4551                overshoot -= 1;
4552                bias = Bias::Right;
4553            }
4554
4555            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4556            let text_anchor =
4557                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4558            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
4559            match diff_base_anchor {
4560                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
4561                None => anchor,
4562            }
4563        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4564            Anchor::min()
4565        } else {
4566            Anchor::max()
4567        }
4568    }
4569
4570    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
4571    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
4572        let (excerpt, buffer, _) = self.as_singleton()?;
4573        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
4574    }
4575
4576    /// Returns an anchor for the given excerpt and text anchor,
4577    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4578    pub fn anchor_range_in_excerpt(
4579        &self,
4580        excerpt_id: ExcerptId,
4581        text_anchor: Range<text::Anchor>,
4582    ) -> Option<Range<Anchor>> {
4583        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4584        let excerpt = self.excerpt(excerpt_id)?;
4585
4586        Some(
4587            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
4588                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
4589        )
4590    }
4591
4592    /// Returns an anchor for the given excerpt and text anchor,
4593    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4594    pub fn anchor_in_excerpt(
4595        &self,
4596        excerpt_id: ExcerptId,
4597        text_anchor: text::Anchor,
4598    ) -> Option<Anchor> {
4599        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4600        let excerpt = self.excerpt(excerpt_id)?;
4601        self.anchor_in_excerpt_(excerpt, text_anchor)
4602    }
4603
4604    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
4605        match text_anchor.buffer_id {
4606            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
4607            Some(_) => return None,
4608            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
4609                return Some(Anchor::in_buffer(
4610                    excerpt.id,
4611                    excerpt.buffer_id,
4612                    text_anchor,
4613                ));
4614            }
4615            None => return None,
4616        }
4617
4618        let context = &excerpt.range.context;
4619        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
4620            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
4621        {
4622            return None;
4623        }
4624
4625        Some(Anchor::in_buffer(
4626            excerpt.id,
4627            excerpt.buffer_id,
4628            text_anchor,
4629        ))
4630    }
4631
4632    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4633        Some(self.excerpt(excerpt_id)?.range.context.clone())
4634    }
4635
4636    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4637        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4638            true
4639        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4640            excerpt.buffer.can_resolve(&anchor.text_anchor)
4641        } else {
4642            false
4643        }
4644    }
4645
4646    pub fn excerpts(
4647        &self,
4648    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4649        self.excerpts
4650            .iter()
4651            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4652    }
4653
4654    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
4655        let excerpts = self.excerpts.cursor(());
4656        let diff_transforms = self.diff_transforms.cursor(());
4657        MultiBufferCursor {
4658            excerpts,
4659            diff_transforms,
4660            diffs: &self.diffs,
4661            cached_region: None,
4662        }
4663    }
4664
4665    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4666        let start_locator = self.excerpt_locator_for_id(excerpt_id);
4667        let mut excerpts = self
4668            .excerpts
4669            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(());
4670        excerpts.seek(&Some(start_locator), Bias::Left);
4671        excerpts.prev();
4672
4673        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(());
4674        diff_transforms.seek(&excerpts.start().1, Bias::Left);
4675        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
4676            diff_transforms.next();
4677        }
4678
4679        let excerpt = excerpts.item()?;
4680        Some(MultiBufferExcerpt {
4681            excerpt,
4682            offset: diff_transforms.start().output_dimension.0,
4683            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4684            excerpt_offset: excerpts.start().1.clone(),
4685            diff_transforms,
4686        })
4687    }
4688
4689    pub fn excerpt_boundaries_in_range<R, T>(
4690        &self,
4691        range: R,
4692    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4693    where
4694        R: RangeBounds<T>,
4695        T: ToOffset,
4696    {
4697        let start_offset;
4698        let start = match range.start_bound() {
4699            Bound::Included(start) => {
4700                start_offset = start.to_offset(self);
4701                Bound::Included(start_offset)
4702            }
4703            Bound::Excluded(_) => {
4704                panic!("not supported")
4705            }
4706            Bound::Unbounded => {
4707                start_offset = 0;
4708                Bound::Unbounded
4709            }
4710        };
4711        let end = match range.end_bound() {
4712            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4713            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4714            Bound::Unbounded => Bound::Unbounded,
4715        };
4716        let bounds = (start, end);
4717
4718        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4719        cursor.seek(&DimensionPair {
4720            key: start_offset,
4721            value: None,
4722        });
4723
4724        if cursor
4725            .region()
4726            .is_some_and(|region| bounds.contains(&region.range.start.key))
4727        {
4728            cursor.prev_excerpt();
4729        } else {
4730            cursor.seek_to_start_of_current_excerpt();
4731        }
4732        let mut prev_region = cursor.region();
4733
4734        cursor.next_excerpt();
4735
4736        iter::from_fn(move || {
4737            loop {
4738                if self.singleton {
4739                    return None;
4740                }
4741
4742                let next_region = cursor.region()?;
4743                cursor.next_excerpt();
4744                if !bounds.contains(&next_region.range.start.key) {
4745                    prev_region = Some(next_region);
4746                    continue;
4747                }
4748
4749                let next_region_start = next_region.range.start.value.unwrap();
4750                let next_region_end = if let Some(region) = cursor.region() {
4751                    region.range.start.value.unwrap()
4752                } else {
4753                    self.max_point()
4754                };
4755
4756                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4757                    id: region.excerpt.id,
4758                    buffer: region.excerpt.buffer.clone(),
4759                    buffer_id: region.excerpt.buffer_id,
4760                    range: region.excerpt.range.clone(),
4761                    end_row: MultiBufferRow(next_region_start.row),
4762                });
4763
4764                let next = ExcerptInfo {
4765                    id: next_region.excerpt.id,
4766                    buffer: next_region.excerpt.buffer.clone(),
4767                    buffer_id: next_region.excerpt.buffer_id,
4768                    range: next_region.excerpt.range.clone(),
4769                    end_row: if next_region.excerpt.has_trailing_newline {
4770                        MultiBufferRow(next_region_end.row - 1)
4771                    } else {
4772                        MultiBufferRow(next_region_end.row)
4773                    },
4774                };
4775
4776                let row = MultiBufferRow(next_region_start.row);
4777
4778                prev_region = Some(next_region);
4779
4780                return Some(ExcerptBoundary { row, prev, next });
4781            }
4782        })
4783    }
4784
4785    pub fn edit_count(&self) -> usize {
4786        self.edit_count
4787    }
4788
4789    pub fn non_text_state_update_count(&self) -> usize {
4790        self.non_text_state_update_count
4791    }
4792
4793    /// Returns the smallest enclosing bracket ranges containing the given range or
4794    /// None if no brackets contain range or the range is not contained in a single
4795    /// excerpt
4796    ///
4797    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4798    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4799        &self,
4800        range: Range<T>,
4801        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4802    ) -> Option<(Range<usize>, Range<usize>)> {
4803        let range = range.start.to_offset(self)..range.end.to_offset(self);
4804        let mut excerpt = self.excerpt_containing(range.clone())?;
4805        let buffer = excerpt.buffer();
4806        let excerpt_buffer_range = excerpt.buffer_range();
4807
4808        // Filter to ranges contained in the excerpt
4809        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4810            excerpt_buffer_range.contains(&open.start)
4811                && excerpt_buffer_range.contains(&close.end)
4812                && range_filter.is_none_or(|filter| filter(buffer, open, close))
4813        };
4814
4815        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4816            excerpt.map_range_to_buffer(range),
4817            Some(&range_filter),
4818        )?;
4819
4820        Some((
4821            excerpt.map_range_from_buffer(open),
4822            excerpt.map_range_from_buffer(close),
4823        ))
4824    }
4825
4826    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4827    /// not contained in a single excerpt
4828    pub fn enclosing_bracket_ranges<T: ToOffset>(
4829        &self,
4830        range: Range<T>,
4831    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4832        let range = range.start.to_offset(self)..range.end.to_offset(self);
4833        let mut excerpt = self.excerpt_containing(range.clone())?;
4834
4835        Some(
4836            excerpt
4837                .buffer()
4838                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4839                .filter_map(move |pair| {
4840                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
4841                        Some((
4842                            excerpt.map_range_from_buffer(pair.open_range),
4843                            excerpt.map_range_from_buffer(pair.close_range),
4844                        ))
4845                    } else {
4846                        None
4847                    }
4848                }),
4849        )
4850    }
4851
4852    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4853    /// not contained in a single excerpt
4854    pub fn text_object_ranges<T: ToOffset>(
4855        &self,
4856        range: Range<T>,
4857        options: TreeSitterOptions,
4858    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4859        let range = range.start.to_offset(self)..range.end.to_offset(self);
4860        self.excerpt_containing(range.clone())
4861            .map(|mut excerpt| {
4862                excerpt
4863                    .buffer()
4864                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4865                    .filter_map(move |(range, text_object)| {
4866                        if excerpt.contains_buffer_range(range.clone()) {
4867                            Some((excerpt.map_range_from_buffer(range), text_object))
4868                        } else {
4869                            None
4870                        }
4871                    })
4872            })
4873            .into_iter()
4874            .flatten()
4875    }
4876
4877    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4878    /// not contained in a single excerpt
4879    pub fn bracket_ranges<T: ToOffset>(
4880        &self,
4881        range: Range<T>,
4882    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4883        let range = range.start.to_offset(self)..range.end.to_offset(self);
4884        let mut excerpt = self.excerpt_containing(range.clone())?;
4885
4886        Some(
4887            excerpt
4888                .buffer()
4889                .bracket_ranges(excerpt.map_range_to_buffer(range))
4890                .filter_map(move |pair| {
4891                    let buffer_range = pair.open_range.start..pair.close_range.end;
4892                    if excerpt.contains_buffer_range(buffer_range) {
4893                        Some((
4894                            excerpt.map_range_from_buffer(pair.open_range),
4895                            excerpt.map_range_from_buffer(pair.close_range),
4896                        ))
4897                    } else {
4898                        None
4899                    }
4900                }),
4901        )
4902    }
4903
4904    pub fn redacted_ranges<'a, T: ToOffset>(
4905        &'a self,
4906        range: Range<T>,
4907        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
4908    ) -> impl Iterator<Item = Range<usize>> + 'a {
4909        let range = range.start.to_offset(self)..range.end.to_offset(self);
4910        self.lift_buffer_metadata(range, move |buffer, range| {
4911            if redaction_enabled(buffer.file()) {
4912                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
4913            } else {
4914                None
4915            }
4916        })
4917        .map(|(range, _, _)| range)
4918    }
4919
4920    pub fn runnable_ranges(
4921        &self,
4922        range: Range<Anchor>,
4923    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
4924        let range = range.start.to_offset(self)..range.end.to_offset(self);
4925        self.lift_buffer_metadata(range, move |buffer, range| {
4926            Some(
4927                buffer
4928                    .runnable_ranges(range.clone())
4929                    .filter(move |runnable| {
4930                        runnable.run_range.start >= range.start
4931                            && runnable.run_range.end < range.end
4932                    })
4933                    .map(|runnable| (runnable.run_range.clone(), runnable)),
4934            )
4935        })
4936        .map(|(run_range, runnable, _)| language::RunnableRange {
4937            run_range,
4938            ..runnable
4939        })
4940    }
4941
4942    pub fn line_indents(
4943        &self,
4944        start_row: MultiBufferRow,
4945        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
4946    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
4947        let max_point = self.max_point();
4948        let mut cursor = self.cursor::<Point>();
4949        cursor.seek(&Point::new(start_row.0, 0));
4950        iter::from_fn(move || {
4951            let mut region = cursor.region()?;
4952            while !buffer_filter(&region.excerpt.buffer) {
4953                cursor.next();
4954                region = cursor.region()?;
4955            }
4956            let overshoot = start_row.0.saturating_sub(region.range.start.row);
4957            let buffer_start_row =
4958                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
4959
4960            let buffer_end_row = if region.is_main_buffer
4961                && (region.has_trailing_newline || region.range.end == max_point)
4962            {
4963                region.buffer_range.end.row
4964            } else {
4965                region.buffer_range.end.row.saturating_sub(1)
4966            };
4967
4968            let line_indents = region
4969                .buffer
4970                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
4971            cursor.next();
4972            Some(line_indents.map(move |(buffer_row, indent)| {
4973                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
4974                (MultiBufferRow(row), indent, &region.excerpt.buffer)
4975            }))
4976        })
4977        .flatten()
4978    }
4979
4980    pub fn reversed_line_indents(
4981        &self,
4982        end_row: MultiBufferRow,
4983        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
4984    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
4985        let max_point = self.max_point();
4986        let mut cursor = self.cursor::<Point>();
4987        cursor.seek(&Point::new(end_row.0, 0));
4988        iter::from_fn(move || {
4989            let mut region = cursor.region()?;
4990            while !buffer_filter(&region.excerpt.buffer) {
4991                cursor.prev();
4992                region = cursor.region()?;
4993            }
4994
4995            let buffer_start_row = region.buffer_range.start.row;
4996            let buffer_end_row = if region.is_main_buffer
4997                && (region.has_trailing_newline || region.range.end == max_point)
4998            {
4999                region.buffer_range.end.row + 1
5000            } else {
5001                region.buffer_range.end.row
5002            };
5003
5004            let overshoot = end_row.0 - region.range.start.row;
5005            let buffer_end_row =
5006                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5007
5008            let line_indents = region
5009                .buffer
5010                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5011            cursor.prev();
5012            Some(line_indents.map(move |(buffer_row, indent)| {
5013                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5014                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5015            }))
5016        })
5017        .flatten()
5018    }
5019
5020    pub async fn enclosing_indent(
5021        &self,
5022        mut target_row: MultiBufferRow,
5023    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5024        let max_row = MultiBufferRow(self.max_point().row);
5025        if target_row >= max_row {
5026            return None;
5027        }
5028
5029        let mut target_indent = self.line_indent_for_row(target_row);
5030
5031        // If the current row is at the start of an indented block, we want to return this
5032        // block as the enclosing indent.
5033        if !target_indent.is_line_empty() && target_row < max_row {
5034            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5035            if !next_line_indent.is_line_empty()
5036                && target_indent.raw_len() < next_line_indent.raw_len()
5037            {
5038                target_indent = next_line_indent;
5039                target_row.0 += 1;
5040            }
5041        }
5042
5043        const SEARCH_ROW_LIMIT: u32 = 25000;
5044        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5045        const YIELD_INTERVAL: u32 = 100;
5046
5047        let mut accessed_row_counter = 0;
5048
5049        // If there is a blank line at the current row, search for the next non indented lines
5050        if target_indent.is_line_empty() {
5051            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5052            let end =
5053                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5054
5055            let mut non_empty_line_above = None;
5056            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5057                if row < start {
5058                    break;
5059                }
5060                accessed_row_counter += 1;
5061                if accessed_row_counter == YIELD_INTERVAL {
5062                    accessed_row_counter = 0;
5063                    yield_now().await;
5064                }
5065                if !indent.is_line_empty() {
5066                    non_empty_line_above = Some((row, indent));
5067                    break;
5068                }
5069            }
5070
5071            let mut non_empty_line_below = None;
5072            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5073                if row > end {
5074                    break;
5075                }
5076                accessed_row_counter += 1;
5077                if accessed_row_counter == YIELD_INTERVAL {
5078                    accessed_row_counter = 0;
5079                    yield_now().await;
5080                }
5081                if !indent.is_line_empty() {
5082                    non_empty_line_below = Some((row, indent));
5083                    break;
5084                }
5085            }
5086
5087            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5088                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5089                    if above_indent.raw_len() >= below_indent.raw_len() {
5090                        (above_row, above_indent)
5091                    } else {
5092                        (below_row, below_indent)
5093                    }
5094                }
5095                (Some(above), None) => above,
5096                (None, Some(below)) => below,
5097                _ => return None,
5098            };
5099
5100            target_indent = indent;
5101            target_row = row;
5102        }
5103
5104        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5105        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5106
5107        let mut start_indent = None;
5108        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5109            if row < start {
5110                break;
5111            }
5112            accessed_row_counter += 1;
5113            if accessed_row_counter == YIELD_INTERVAL {
5114                accessed_row_counter = 0;
5115                yield_now().await;
5116            }
5117            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5118                start_indent = Some((row, indent));
5119                break;
5120            }
5121        }
5122        let (start_row, start_indent_size) = start_indent?;
5123
5124        let mut end_indent = (end, None);
5125        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5126            if row > end {
5127                break;
5128            }
5129            accessed_row_counter += 1;
5130            if accessed_row_counter == YIELD_INTERVAL {
5131                accessed_row_counter = 0;
5132                yield_now().await;
5133            }
5134            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5135                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5136                break;
5137            }
5138        }
5139        let (end_row, end_indent_size) = end_indent;
5140
5141        let indent = if let Some(end_indent_size) = end_indent_size {
5142            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5143                start_indent_size
5144            } else {
5145                end_indent_size
5146            }
5147        } else {
5148            start_indent_size
5149        };
5150
5151        Some((start_row..end_row, indent))
5152    }
5153
5154    pub fn indent_guides_in_range<T: ToPoint>(
5155        &self,
5156        range: Range<T>,
5157        ignore_disabled_for_language: bool,
5158        cx: &App,
5159    ) -> impl Iterator<Item = IndentGuide> {
5160        let range = range.start.to_point(self)..range.end.to_point(self);
5161        let start_row = MultiBufferRow(range.start.row);
5162        let end_row = MultiBufferRow(range.end.row);
5163
5164        let mut row_indents = self.line_indents(start_row, |buffer| {
5165            let settings =
5166                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5167            settings.indent_guides.enabled || ignore_disabled_for_language
5168        });
5169
5170        let mut result = Vec::new();
5171        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5172
5173        let mut prev_settings = None;
5174        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5175            if first_row > end_row {
5176                break;
5177            }
5178            let current_depth = indent_stack.len() as u32;
5179
5180            // Avoid retrieving the language settings repeatedly for every buffer row.
5181            if let Some((prev_buffer_id, _)) = &prev_settings
5182                && prev_buffer_id != &buffer.remote_id()
5183            {
5184                prev_settings.take();
5185            }
5186            let settings = &prev_settings
5187                .get_or_insert_with(|| {
5188                    (
5189                        buffer.remote_id(),
5190                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5191                    )
5192                })
5193                .1;
5194            let tab_size = settings.tab_size.get();
5195
5196            // When encountering empty, continue until found useful line indent
5197            // then add to the indent stack with the depth found
5198            let mut found_indent = false;
5199            let mut last_row = first_row;
5200            if line_indent.is_line_blank() {
5201                while !found_indent {
5202                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5203                        break;
5204                    };
5205                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5206                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5207                        break;
5208                    }
5209
5210                    if new_line_indent.is_line_blank() {
5211                        continue;
5212                    }
5213                    last_row = target_row.min(end_row);
5214                    line_indent = new_line_indent;
5215                    found_indent = true;
5216                    break;
5217                }
5218            } else {
5219                found_indent = true
5220            }
5221
5222            let depth = if found_indent {
5223                line_indent.len(tab_size) / tab_size
5224            } else {
5225                0
5226            };
5227
5228            match depth.cmp(&current_depth) {
5229                cmp::Ordering::Less => {
5230                    for _ in 0..(current_depth - depth) {
5231                        let mut indent = indent_stack.pop().unwrap();
5232                        if last_row != first_row {
5233                            // In this case, we landed on an empty row, had to seek forward,
5234                            // and discovered that the indent we where on is ending.
5235                            // This means that the last display row must
5236                            // be on line that ends this indent range, so we
5237                            // should display the range up to the first non-empty line
5238                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5239                        }
5240
5241                        result.push(indent)
5242                    }
5243                }
5244                cmp::Ordering::Greater => {
5245                    for next_depth in current_depth..depth {
5246                        indent_stack.push(IndentGuide {
5247                            buffer_id: buffer.remote_id(),
5248                            start_row: first_row,
5249                            end_row: last_row,
5250                            depth: next_depth,
5251                            tab_size,
5252                            settings: settings.indent_guides.clone(),
5253                        });
5254                    }
5255                }
5256                _ => {}
5257            }
5258
5259            for indent in indent_stack.iter_mut() {
5260                indent.end_row = last_row;
5261            }
5262        }
5263
5264        result.extend(indent_stack);
5265        result.into_iter()
5266    }
5267
5268    pub fn trailing_excerpt_update_count(&self) -> usize {
5269        self.trailing_excerpt_update_count
5270    }
5271
5272    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5273        self.point_to_buffer_offset(point)
5274            .and_then(|(buffer, _)| buffer.file())
5275    }
5276
5277    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5278        self.point_to_buffer_offset(point)
5279            .and_then(|(buffer, offset)| buffer.language_at(offset))
5280    }
5281
5282    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5283        self.excerpts
5284            .first()
5285            .map(|excerpt| &excerpt.buffer)
5286            .map(|buffer| {
5287                language_settings(
5288                    buffer.language().map(|language| language.name()),
5289                    buffer.file(),
5290                    cx,
5291                )
5292            })
5293            .unwrap_or_else(move || self.language_settings_at(0, cx))
5294    }
5295
5296    pub fn language_settings_at<'a, T: ToOffset>(
5297        &'a self,
5298        point: T,
5299        cx: &'a App,
5300    ) -> Cow<'a, LanguageSettings> {
5301        let mut language = None;
5302        let mut file = None;
5303        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5304            language = buffer.language_at(offset);
5305            file = buffer.file();
5306        }
5307        language_settings(language.map(|l| l.name()), file, cx)
5308    }
5309
5310    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5311        self.point_to_buffer_offset(point)
5312            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5313    }
5314
5315    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5316        self.point_to_buffer_offset(point)
5317            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5318            .unwrap_or_default()
5319    }
5320
5321    pub fn language_indent_size_at<T: ToOffset>(
5322        &self,
5323        position: T,
5324        cx: &App,
5325    ) -> Option<IndentSize> {
5326        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5327        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5328    }
5329
5330    pub fn is_dirty(&self) -> bool {
5331        self.is_dirty
5332    }
5333
5334    pub fn has_deleted_file(&self) -> bool {
5335        self.has_deleted_file
5336    }
5337
5338    pub fn has_conflict(&self) -> bool {
5339        self.has_conflict
5340    }
5341
5342    pub fn has_diagnostics(&self) -> bool {
5343        self.excerpts
5344            .iter()
5345            .any(|excerpt| excerpt.buffer.has_diagnostics())
5346    }
5347
5348    pub fn diagnostic_group(
5349        &self,
5350        buffer_id: BufferId,
5351        group_id: usize,
5352    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5353        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
5354            if buffer.remote_id() != buffer_id {
5355                return None;
5356            };
5357            Some(
5358                buffer
5359                    .diagnostics_in_range(range, false)
5360                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5361                    .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
5362            )
5363        })
5364        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5365    }
5366
5367    pub fn diagnostics_in_range<'a, T>(
5368        &'a self,
5369        range: Range<T>,
5370    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, T>> + 'a
5371    where
5372        T: 'a
5373            + text::ToOffset
5374            + text::FromAnchor
5375            + TextDimension
5376            + Ord
5377            + Sub<T, Output = T>
5378            + fmt::Debug,
5379    {
5380        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5381            Some(
5382                buffer
5383                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5384                    .map(|entry| (entry.range, entry.diagnostic)),
5385            )
5386        })
5387        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5388    }
5389
5390    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
5391        &'a self,
5392        range: Range<T>,
5393    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, T>)> + 'a
5394    where
5395        T: 'a
5396            + text::ToOffset
5397            + text::FromAnchor
5398            + TextDimension
5399            + Ord
5400            + Sub<T, Output = T>
5401            + fmt::Debug,
5402    {
5403        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5404            Some(
5405                buffer
5406                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5407                    .map(|entry| (entry.range, entry.diagnostic)),
5408            )
5409        })
5410        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
5411    }
5412
5413    pub fn syntax_ancestor<T: ToOffset>(
5414        &self,
5415        range: Range<T>,
5416    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
5417        let range = range.start.to_offset(self)..range.end.to_offset(self);
5418        let mut excerpt = self.excerpt_containing(range.clone())?;
5419        let node = excerpt
5420            .buffer()
5421            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5422        let node_range = node.byte_range();
5423        if !excerpt.contains_buffer_range(node_range.clone()) {
5424            return None;
5425        };
5426        Some((node, excerpt.map_range_from_buffer(node_range)))
5427    }
5428
5429    pub fn syntax_next_sibling<T: ToOffset>(
5430        &self,
5431        range: Range<T>,
5432    ) -> Option<tree_sitter::Node<'_>> {
5433        let range = range.start.to_offset(self)..range.end.to_offset(self);
5434        let mut excerpt = self.excerpt_containing(range.clone())?;
5435        excerpt
5436            .buffer()
5437            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
5438    }
5439
5440    pub fn syntax_prev_sibling<T: ToOffset>(
5441        &self,
5442        range: Range<T>,
5443    ) -> Option<tree_sitter::Node<'_>> {
5444        let range = range.start.to_offset(self)..range.end.to_offset(self);
5445        let mut excerpt = self.excerpt_containing(range.clone())?;
5446        excerpt
5447            .buffer()
5448            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
5449    }
5450
5451    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5452        let (excerpt_id, _, buffer) = self.as_singleton()?;
5453        let outline = buffer.outline(theme);
5454        Some(Outline::new(
5455            outline
5456                .items
5457                .into_iter()
5458                .flat_map(|item| {
5459                    Some(OutlineItem {
5460                        depth: item.depth,
5461                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
5462                        source_range_for_text: self
5463                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
5464                        text: item.text,
5465                        highlight_ranges: item.highlight_ranges,
5466                        name_ranges: item.name_ranges,
5467                        body_range: item.body_range.and_then(|body_range| {
5468                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
5469                        }),
5470                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5471                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
5472                        }),
5473                    })
5474                })
5475                .collect(),
5476        ))
5477    }
5478
5479    pub fn symbols_containing<T: ToOffset>(
5480        &self,
5481        offset: T,
5482        theme: Option<&SyntaxTheme>,
5483    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5484        let anchor = self.anchor_before(offset);
5485        let excerpt_id = anchor.excerpt_id;
5486        let excerpt = self.excerpt(excerpt_id)?;
5487        let buffer_id = excerpt.buffer_id;
5488        Some((
5489            buffer_id,
5490            excerpt
5491                .buffer
5492                .symbols_containing(anchor.text_anchor, theme)
5493                .into_iter()
5494                .flat_map(|item| {
5495                    Some(OutlineItem {
5496                        depth: item.depth,
5497                        source_range_for_text: Anchor::range_in_buffer(
5498                            excerpt_id,
5499                            buffer_id,
5500                            item.source_range_for_text,
5501                        ),
5502                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
5503                        text: item.text,
5504                        highlight_ranges: item.highlight_ranges,
5505                        name_ranges: item.name_ranges,
5506                        body_range: item.body_range.map(|body_range| {
5507                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5508                        }),
5509                        annotation_range: item.annotation_range.map(|body_range| {
5510                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5511                        }),
5512                    })
5513                })
5514                .collect(),
5515        ))
5516    }
5517
5518    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5519        if id == ExcerptId::min() {
5520            Locator::min_ref()
5521        } else if id == ExcerptId::max() {
5522            Locator::max_ref()
5523        } else {
5524            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
5525            if let Some(entry) = item
5526                && entry.id == id
5527            {
5528                return &entry.locator;
5529            }
5530            panic!("invalid excerpt id {id:?}")
5531        }
5532    }
5533
5534    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5535    fn excerpt_locators_for_ids(
5536        &self,
5537        ids: impl IntoIterator<Item = ExcerptId>,
5538    ) -> SmallVec<[Locator; 1]> {
5539        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5540        sorted_ids.sort_unstable();
5541        sorted_ids.dedup();
5542        let mut locators = SmallVec::new();
5543
5544        while sorted_ids.last() == Some(&ExcerptId::max()) {
5545            sorted_ids.pop();
5546            locators.push(Locator::max());
5547        }
5548
5549        let mut sorted_ids = sorted_ids.into_iter().peekable();
5550        locators.extend(
5551            sorted_ids
5552                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
5553                .map(|_| Locator::min()),
5554        );
5555
5556        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
5557        for id in sorted_ids {
5558            if cursor.seek_forward(&id, Bias::Left) {
5559                locators.push(cursor.item().unwrap().locator.clone());
5560            } else {
5561                panic!("invalid excerpt id {:?}", id);
5562            }
5563        }
5564
5565        locators.sort_unstable();
5566        locators
5567    }
5568
5569    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5570        Some(self.excerpt(excerpt_id)?.buffer_id)
5571    }
5572
5573    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5574        Some(&self.excerpt(excerpt_id)?.buffer)
5575    }
5576
5577    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5578        let mut cursor = self
5579            .excerpts
5580            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
5581        let locator = self.excerpt_locator_for_id(excerpt_id);
5582        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
5583        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5584            sought_exact = true;
5585            cursor.prev();
5586        } else if excerpt_id == ExcerptId::min() {
5587            sought_exact = true;
5588        }
5589        if sought_exact {
5590            let start = cursor.start().1.clone();
5591            let end = cursor.end().1;
5592            let mut diff_transforms = self
5593                .diff_transforms
5594                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
5595            diff_transforms.seek(&start, Bias::Left);
5596            let overshoot = start.0 - diff_transforms.start().0.0;
5597            let start = diff_transforms.start().1.0 + overshoot;
5598            diff_transforms.seek(&end, Bias::Right);
5599            let overshoot = end.0 - diff_transforms.start().0.0;
5600            let end = diff_transforms.start().1.0 + overshoot;
5601            Some(start..end)
5602        } else {
5603            None
5604        }
5605    }
5606
5607    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5608        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5609        let locator = self.excerpt_locator_for_id(excerpt_id);
5610        cursor.seek(&Some(locator), Bias::Left);
5611        if let Some(excerpt) = cursor.item()
5612            && excerpt.id == excerpt_id
5613        {
5614            return Some(excerpt);
5615        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5616            cursor.prev();
5617            return cursor.item();
5618        }
5619        None
5620    }
5621
5622    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5623    pub fn excerpt_containing<T: ToOffset>(
5624        &self,
5625        range: Range<T>,
5626    ) -> Option<MultiBufferExcerpt<'_>> {
5627        let range = range.start.to_offset(self)..range.end.to_offset(self);
5628        let mut cursor = self.cursor::<usize>();
5629        cursor.seek(&range.start);
5630
5631        let start_excerpt = cursor.excerpt()?;
5632        if range.end != range.start {
5633            cursor.seek_forward(&range.end);
5634            if cursor.excerpt()?.id != start_excerpt.id {
5635                return None;
5636            }
5637        }
5638
5639        cursor.seek_to_start_of_current_excerpt();
5640        let region = cursor.region()?;
5641        let offset = region.range.start;
5642        let buffer_offset = start_excerpt.buffer_start_offset();
5643        let excerpt_offset = cursor.excerpts.start().clone();
5644        Some(MultiBufferExcerpt {
5645            diff_transforms: cursor.diff_transforms,
5646            excerpt: start_excerpt,
5647            offset,
5648            buffer_offset,
5649            excerpt_offset,
5650        })
5651    }
5652
5653    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
5654        if let Some(id) = anchor.buffer_id {
5655            return Some(id);
5656        }
5657        let excerpt = self.excerpt_containing(anchor..anchor)?;
5658        Some(excerpt.buffer_id())
5659    }
5660
5661    pub fn selections_in_range<'a>(
5662        &'a self,
5663        range: &'a Range<Anchor>,
5664        include_local: bool,
5665    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5666        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5667        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5668        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5669        cursor.seek(start_locator, Bias::Left);
5670        cursor
5671            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5672            .flat_map(move |excerpt| {
5673                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5674                if excerpt.id == range.start.excerpt_id {
5675                    query_range.start = range.start.text_anchor;
5676                }
5677                if excerpt.id == range.end.excerpt_id {
5678                    query_range.end = range.end.text_anchor;
5679                }
5680
5681                excerpt
5682                    .buffer
5683                    .selections_in_range(query_range, include_local)
5684                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5685                        selections.map(move |selection| {
5686                            let mut start =
5687                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
5688                            let mut end =
5689                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
5690                            if range.start.cmp(&start, self).is_gt() {
5691                                start = range.start;
5692                            }
5693                            if range.end.cmp(&end, self).is_lt() {
5694                                end = range.end;
5695                            }
5696
5697                            (
5698                                replica_id,
5699                                line_mode,
5700                                cursor_shape,
5701                                Selection {
5702                                    id: selection.id,
5703                                    start,
5704                                    end,
5705                                    reversed: selection.reversed,
5706                                    goal: selection.goal,
5707                                },
5708                            )
5709                        })
5710                    })
5711            })
5712    }
5713
5714    pub fn show_headers(&self) -> bool {
5715        self.show_headers
5716    }
5717
5718    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5719        self.diffs.get(&buffer_id)
5720    }
5721
5722    /// Visually annotates a position or range with the `Debug` representation of a value. The
5723    /// callsite of this function is used as a key - previous annotations will be removed.
5724    #[cfg(debug_assertions)]
5725    #[track_caller]
5726    pub fn debug<V, R>(&self, ranges: &R, value: V)
5727    where
5728        R: debug::ToMultiBufferDebugRanges,
5729        V: std::fmt::Debug,
5730    {
5731        self.debug_with_key(std::panic::Location::caller(), ranges, value);
5732    }
5733
5734    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
5735    /// debug annotations with the same key will be removed. The key is also used to determine the
5736    /// annotation's color.
5737    #[cfg(debug_assertions)]
5738    #[track_caller]
5739    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
5740    where
5741        K: std::hash::Hash + 'static,
5742        R: debug::ToMultiBufferDebugRanges,
5743        V: std::fmt::Debug,
5744    {
5745        let text_ranges = ranges
5746            .to_multi_buffer_debug_ranges(self)
5747            .into_iter()
5748            .flat_map(|range| {
5749                self.range_to_buffer_ranges(range).into_iter().map(
5750                    |(buffer, range, _excerpt_id)| {
5751                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
5752                    },
5753                )
5754            })
5755            .collect();
5756        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
5757            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
5758        });
5759    }
5760}
5761
5762#[cfg(any(test, feature = "test-support"))]
5763impl MultiBufferSnapshot {
5764    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5765        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
5766        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
5767        start..end
5768    }
5769
5770    #[cfg(any(test, feature = "test-support"))]
5771    fn check_invariants(&self) {
5772        let excerpts = self.excerpts.items(());
5773        let excerpt_ids = self.excerpt_ids.items(());
5774
5775        for (ix, excerpt) in excerpts.iter().enumerate() {
5776            if ix == 0 {
5777                if excerpt.locator <= Locator::min() {
5778                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5779                }
5780            } else if excerpt.locator <= excerpts[ix - 1].locator {
5781                panic!("excerpts are out-of-order: {:?}", excerpts);
5782            }
5783        }
5784
5785        for (ix, entry) in excerpt_ids.iter().enumerate() {
5786            if ix == 0 {
5787                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
5788                    panic!("invalid first excerpt id {:?}", entry.id);
5789                }
5790            } else if entry.id <= excerpt_ids[ix - 1].id {
5791                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5792            }
5793        }
5794
5795        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5796            panic!(
5797                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5798                self.excerpts.summary().text.len,
5799                self.diff_transforms.summary().input,
5800                self.diff_transforms.items(()),
5801            );
5802        }
5803
5804        let mut prev_transform: Option<&DiffTransform> = None;
5805        for item in self.diff_transforms.iter() {
5806            if let DiffTransform::BufferContent {
5807                summary,
5808                inserted_hunk_info,
5809            } = item
5810            {
5811                if let Some(DiffTransform::BufferContent {
5812                    inserted_hunk_info: prev_inserted_hunk_info,
5813                    ..
5814                }) = prev_transform
5815                    && *inserted_hunk_info == *prev_inserted_hunk_info
5816                {
5817                    panic!(
5818                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
5819                        self.diff_transforms.items(())
5820                    );
5821                }
5822                if summary.len == 0 && !self.is_empty() {
5823                    panic!("empty buffer content transform");
5824                }
5825            }
5826            prev_transform = Some(item);
5827        }
5828    }
5829}
5830
5831impl<'a, D> MultiBufferCursor<'a, D>
5832where
5833    D: TextDimension + Ord + Sub<D, Output = D>,
5834{
5835    fn seek(&mut self, position: &D) {
5836        self.cached_region.take();
5837        self.diff_transforms
5838            .seek(&OutputDimension(*position), Bias::Right);
5839        if self.diff_transforms.item().is_none()
5840            && *position == self.diff_transforms.start().output_dimension.0
5841        {
5842            self.diff_transforms.prev();
5843        }
5844
5845        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5846        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5847            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5848            excerpt_position.add_assign(&overshoot);
5849        }
5850
5851        self.excerpts
5852            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
5853        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5854            self.excerpts.prev();
5855        }
5856    }
5857
5858    fn seek_forward(&mut self, position: &D) {
5859        self.cached_region.take();
5860        self.diff_transforms
5861            .seek_forward(&OutputDimension(*position), Bias::Right);
5862        if self.diff_transforms.item().is_none()
5863            && *position == self.diff_transforms.start().output_dimension.0
5864        {
5865            self.diff_transforms.prev();
5866        }
5867
5868        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5869        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5870        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5871            excerpt_position.add_assign(&overshoot);
5872        }
5873
5874        self.excerpts
5875            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
5876        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5877            self.excerpts.prev();
5878        }
5879    }
5880
5881    fn next_excerpt(&mut self) {
5882        self.excerpts.next();
5883        self.seek_to_start_of_current_excerpt();
5884    }
5885
5886    fn prev_excerpt(&mut self) {
5887        self.excerpts.prev();
5888        self.seek_to_start_of_current_excerpt();
5889    }
5890
5891    fn seek_to_start_of_current_excerpt(&mut self) {
5892        self.cached_region.take();
5893        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
5894        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
5895            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
5896            && self.diff_transforms.next_item().is_some()
5897        {
5898            self.diff_transforms.next();
5899        }
5900    }
5901
5902    fn next(&mut self) {
5903        self.cached_region.take();
5904        match self
5905            .diff_transforms
5906            .end()
5907            .excerpt_dimension
5908            .cmp(&self.excerpts.end())
5909        {
5910            cmp::Ordering::Less => self.diff_transforms.next(),
5911            cmp::Ordering::Greater => self.excerpts.next(),
5912            cmp::Ordering::Equal => {
5913                self.diff_transforms.next();
5914                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
5915                    || self.diff_transforms.item().is_none()
5916                {
5917                    self.excerpts.next();
5918                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
5919                    self.diff_transforms.item()
5920                    && self
5921                        .excerpts
5922                        .item()
5923                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
5924                {
5925                    self.excerpts.next();
5926                }
5927            }
5928        }
5929    }
5930
5931    fn prev(&mut self) {
5932        self.cached_region.take();
5933        match self
5934            .diff_transforms
5935            .start()
5936            .excerpt_dimension
5937            .cmp(self.excerpts.start())
5938        {
5939            cmp::Ordering::Less => self.excerpts.prev(),
5940            cmp::Ordering::Greater => self.diff_transforms.prev(),
5941            cmp::Ordering::Equal => {
5942                self.diff_transforms.prev();
5943                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
5944                    || self.diff_transforms.item().is_none()
5945                {
5946                    self.excerpts.prev();
5947                }
5948            }
5949        }
5950    }
5951
5952    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
5953        if self.cached_region.is_none() {
5954            self.cached_region = self.build_region();
5955        }
5956        self.cached_region.clone()
5957    }
5958
5959    fn is_at_start_of_excerpt(&mut self) -> bool {
5960        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
5961            return false;
5962        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
5963            return true;
5964        }
5965
5966        self.diff_transforms.prev();
5967        let prev_transform = self.diff_transforms.item();
5968        self.diff_transforms.next();
5969
5970        prev_transform.is_none_or(|next_transform| {
5971            matches!(next_transform, DiffTransform::BufferContent { .. })
5972        })
5973    }
5974
5975    fn is_at_end_of_excerpt(&mut self) -> bool {
5976        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
5977            return false;
5978        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
5979            || self.diff_transforms.item().is_none()
5980        {
5981            return true;
5982        }
5983
5984        let next_transform = self.diff_transforms.next_item();
5985        next_transform.is_none_or(|next_transform| match next_transform {
5986            DiffTransform::BufferContent { .. } => true,
5987            DiffTransform::DeletedHunk { hunk_info, .. } => self
5988                .excerpts
5989                .item()
5990                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
5991        })
5992    }
5993
5994    fn main_buffer_position(&self) -> Option<D> {
5995        let excerpt = self.excerpts.item()?;
5996        let buffer = &excerpt.buffer;
5997        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5998        let mut buffer_start = buffer_context_start;
5999        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6000        buffer_start.add_assign(&overshoot);
6001        Some(buffer_start)
6002    }
6003
6004    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6005        let excerpt = self.excerpts.item()?;
6006        match self.diff_transforms.item()? {
6007            DiffTransform::DeletedHunk {
6008                buffer_id,
6009                base_text_byte_range,
6010                has_trailing_newline,
6011                hunk_info,
6012                ..
6013            } => {
6014                let diff = self.diffs.get(buffer_id)?;
6015                let buffer = diff.base_text();
6016                let mut rope_cursor = buffer.as_rope().cursor(0);
6017                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6018                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6019                let mut buffer_end = buffer_start;
6020                buffer_end.add_assign(&buffer_range_len);
6021                let start = self.diff_transforms.start().output_dimension.0;
6022                let end = self.diff_transforms.end().output_dimension.0;
6023                Some(MultiBufferRegion {
6024                    buffer,
6025                    excerpt,
6026                    has_trailing_newline: *has_trailing_newline,
6027                    is_main_buffer: false,
6028                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6029                        hunk_info.hunk_secondary_status,
6030                    )),
6031                    buffer_range: buffer_start..buffer_end,
6032                    range: start..end,
6033                })
6034            }
6035            DiffTransform::BufferContent {
6036                inserted_hunk_info, ..
6037            } => {
6038                let buffer = &excerpt.buffer;
6039                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6040
6041                let mut start = self.diff_transforms.start().output_dimension.0;
6042                let mut buffer_start = buffer_context_start;
6043                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6044                    let overshoot =
6045                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6046                    start.add_assign(&overshoot);
6047                } else {
6048                    let overshoot =
6049                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6050                    buffer_start.add_assign(&overshoot);
6051                }
6052
6053                let mut end;
6054                let mut buffer_end;
6055                let has_trailing_newline;
6056                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6057                    let overshoot =
6058                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6059                    end = self.diff_transforms.end().output_dimension.0;
6060                    buffer_end = buffer_context_start;
6061                    buffer_end.add_assign(&overshoot);
6062                    has_trailing_newline = false;
6063                } else {
6064                    let overshoot =
6065                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6066                    end = self.diff_transforms.start().output_dimension.0;
6067                    end.add_assign(&overshoot);
6068                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6069                    has_trailing_newline = excerpt.has_trailing_newline;
6070                };
6071
6072                Some(MultiBufferRegion {
6073                    buffer,
6074                    excerpt,
6075                    has_trailing_newline,
6076                    is_main_buffer: true,
6077                    diff_hunk_status: inserted_hunk_info
6078                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6079                    buffer_range: buffer_start..buffer_end,
6080                    range: start..end,
6081                })
6082            }
6083        }
6084    }
6085
6086    fn excerpt(&self) -> Option<&'a Excerpt> {
6087        self.excerpts.item()
6088    }
6089}
6090
6091impl Excerpt {
6092    fn new(
6093        id: ExcerptId,
6094        locator: Locator,
6095        buffer_id: BufferId,
6096        buffer: BufferSnapshot,
6097        range: ExcerptRange<text::Anchor>,
6098        has_trailing_newline: bool,
6099    ) -> Self {
6100        Excerpt {
6101            id,
6102            locator,
6103            max_buffer_row: range.context.end.to_point(&buffer).row,
6104            text_summary: buffer
6105                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6106            buffer_id,
6107            buffer,
6108            range,
6109            has_trailing_newline,
6110        }
6111    }
6112
6113    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6114        let content_start = self.range.context.start.to_offset(&self.buffer);
6115        let chunks_start = content_start + range.start;
6116        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6117
6118        let has_footer = self.has_trailing_newline
6119            && range.start <= self.text_summary.len
6120            && range.end > self.text_summary.len;
6121
6122        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6123
6124        ExcerptChunks {
6125            excerpt_id: self.id,
6126            content_chunks,
6127            has_footer,
6128        }
6129    }
6130
6131    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6132        let content_start = self.range.context.start.to_offset(&self.buffer);
6133        let chunks_start = content_start + range.start;
6134        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6135        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6136        excerpt_chunks.has_footer = self.has_trailing_newline
6137            && range.start <= self.text_summary.len
6138            && range.end > self.text_summary.len;
6139    }
6140
6141    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6142        if text_anchor
6143            .cmp(&self.range.context.start, &self.buffer)
6144            .is_lt()
6145        {
6146            self.range.context.start
6147        } else if text_anchor
6148            .cmp(&self.range.context.end, &self.buffer)
6149            .is_gt()
6150        {
6151            self.range.context.end
6152        } else {
6153            text_anchor
6154        }
6155    }
6156
6157    fn contains(&self, anchor: &Anchor) -> bool {
6158        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6159            && self
6160                .range
6161                .context
6162                .start
6163                .cmp(&anchor.text_anchor, &self.buffer)
6164                .is_le()
6165            && self
6166                .range
6167                .context
6168                .end
6169                .cmp(&anchor.text_anchor, &self.buffer)
6170                .is_ge()
6171    }
6172
6173    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6174    fn buffer_start_offset(&self) -> usize {
6175        self.range.context.start.to_offset(&self.buffer)
6176    }
6177
6178    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6179    fn buffer_end_offset(&self) -> usize {
6180        self.buffer_start_offset() + self.text_summary.len
6181    }
6182}
6183
6184impl<'a> MultiBufferExcerpt<'a> {
6185    pub fn id(&self) -> ExcerptId {
6186        self.excerpt.id
6187    }
6188
6189    pub fn buffer_id(&self) -> BufferId {
6190        self.excerpt.buffer_id
6191    }
6192
6193    pub fn start_anchor(&self) -> Anchor {
6194        Anchor::in_buffer(
6195            self.excerpt.id,
6196            self.excerpt.buffer_id,
6197            self.excerpt.range.context.start,
6198        )
6199    }
6200
6201    pub fn end_anchor(&self) -> Anchor {
6202        Anchor::in_buffer(
6203            self.excerpt.id,
6204            self.excerpt.buffer_id,
6205            self.excerpt.range.context.end,
6206        )
6207    }
6208
6209    pub fn buffer(&self) -> &'a BufferSnapshot {
6210        &self.excerpt.buffer
6211    }
6212
6213    pub fn buffer_range(&self) -> Range<usize> {
6214        self.buffer_offset
6215            ..self
6216                .excerpt
6217                .range
6218                .context
6219                .end
6220                .to_offset(&self.excerpt.buffer.text)
6221    }
6222
6223    pub fn start_offset(&self) -> usize {
6224        self.offset
6225    }
6226
6227    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6228    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6229        self.map_range_to_buffer(offset..offset).start
6230    }
6231
6232    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6233    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6234        self.diff_transforms
6235            .seek(&OutputDimension(range.start), Bias::Right);
6236        let start = self.map_offset_to_buffer_internal(range.start);
6237        let end = if range.end > range.start {
6238            self.diff_transforms
6239                .seek_forward(&OutputDimension(range.end), Bias::Right);
6240            self.map_offset_to_buffer_internal(range.end)
6241        } else {
6242            start
6243        };
6244        start..end
6245    }
6246
6247    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6248        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
6249        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6250            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
6251        };
6252        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6253        self.buffer_offset + offset_in_excerpt
6254    }
6255
6256    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6257    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6258        self.map_range_from_buffer(buffer_offset..buffer_offset)
6259            .start
6260    }
6261
6262    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6263    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6264        if buffer_range.start < self.buffer_offset {
6265            log::warn!(
6266                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6267            );
6268            return buffer_range;
6269        }
6270        let overshoot = buffer_range.start - self.buffer_offset;
6271        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6272        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
6273        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
6274            log::warn!(
6275                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6276            );
6277            return buffer_range;
6278        }
6279        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6280        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
6281
6282        let end = if buffer_range.end > buffer_range.start {
6283            let overshoot = buffer_range.end - self.buffer_offset;
6284            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6285            self.diff_transforms
6286                .seek_forward(&excerpt_offset, Bias::Right);
6287            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6288            self.diff_transforms.start().output_dimension.0 + overshoot
6289        } else {
6290            start
6291        };
6292
6293        start..end
6294    }
6295
6296    /// Returns true if the entirety of the given range is in the buffer's excerpt
6297    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6298        range.start >= self.excerpt.buffer_start_offset()
6299            && range.end <= self.excerpt.buffer_end_offset()
6300    }
6301
6302    pub fn max_buffer_row(&self) -> u32 {
6303        self.excerpt.max_buffer_row
6304    }
6305}
6306
6307impl ExcerptId {
6308    pub fn min() -> Self {
6309        Self(0)
6310    }
6311
6312    pub fn max() -> Self {
6313        Self(u32::MAX)
6314    }
6315
6316    pub fn to_proto(self) -> u64 {
6317        self.0 as _
6318    }
6319
6320    pub fn from_proto(proto: u64) -> Self {
6321        Self(proto as _)
6322    }
6323
6324    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6325        let a = snapshot.excerpt_locator_for_id(*self);
6326        let b = snapshot.excerpt_locator_for_id(*other);
6327        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6328    }
6329}
6330
6331impl From<ExcerptId> for usize {
6332    fn from(val: ExcerptId) -> Self {
6333        val.0 as usize
6334    }
6335}
6336
6337impl fmt::Debug for Excerpt {
6338    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6339        f.debug_struct("Excerpt")
6340            .field("id", &self.id)
6341            .field("locator", &self.locator)
6342            .field("buffer_id", &self.buffer_id)
6343            .field("range", &self.range)
6344            .field("text_summary", &self.text_summary)
6345            .field("has_trailing_newline", &self.has_trailing_newline)
6346            .finish()
6347    }
6348}
6349
6350impl sum_tree::Item for Excerpt {
6351    type Summary = ExcerptSummary;
6352
6353    fn summary(&self, _cx: ()) -> Self::Summary {
6354        let mut text = self.text_summary;
6355        if self.has_trailing_newline {
6356            text += TextSummary::from("\n");
6357        }
6358        ExcerptSummary {
6359            excerpt_id: self.id,
6360            excerpt_locator: self.locator.clone(),
6361            widest_line_number: self.max_buffer_row,
6362            text,
6363        }
6364    }
6365}
6366
6367impl sum_tree::Item for ExcerptIdMapping {
6368    type Summary = ExcerptId;
6369
6370    fn summary(&self, _cx: ()) -> Self::Summary {
6371        self.id
6372    }
6373}
6374
6375impl sum_tree::KeyedItem for ExcerptIdMapping {
6376    type Key = ExcerptId;
6377
6378    fn key(&self) -> Self::Key {
6379        self.id
6380    }
6381}
6382
6383impl DiffTransform {
6384    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6385        match self {
6386            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6387            DiffTransform::BufferContent {
6388                inserted_hunk_info, ..
6389            } => *inserted_hunk_info,
6390        }
6391    }
6392}
6393
6394impl sum_tree::Item for DiffTransform {
6395    type Summary = DiffTransformSummary;
6396
6397    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
6398        match self {
6399            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6400                input: *summary,
6401                output: *summary,
6402            },
6403            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6404                input: TextSummary::default(),
6405                output: *summary,
6406            },
6407        }
6408    }
6409}
6410
6411impl DiffTransformSummary {
6412    fn excerpt_len(&self) -> ExcerptOffset {
6413        ExcerptOffset::new(self.input.len)
6414    }
6415}
6416
6417impl sum_tree::ContextLessSummary for DiffTransformSummary {
6418    fn zero() -> Self {
6419        DiffTransformSummary {
6420            input: TextSummary::default(),
6421            output: TextSummary::default(),
6422        }
6423    }
6424
6425    fn add_summary(&mut self, other: &Self) {
6426        self.input += other.input;
6427        self.output += other.output;
6428    }
6429}
6430
6431impl sum_tree::ContextLessSummary for ExcerptId {
6432    fn zero() -> Self {
6433        Self(0)
6434    }
6435
6436    fn add_summary(&mut self, summary: &Self) {
6437        *self = cmp::max(*self, *summary);
6438    }
6439}
6440
6441impl sum_tree::ContextLessSummary for ExcerptSummary {
6442    fn zero() -> Self {
6443        Self::default()
6444    }
6445
6446    fn add_summary(&mut self, summary: &Self) {
6447        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6448        self.excerpt_locator = summary.excerpt_locator.clone();
6449        Summary::add_summary(&mut self.text, &summary.text, ());
6450        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6451    }
6452}
6453
6454impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6455    fn zero(_cx: ()) -> Self {
6456        Default::default()
6457    }
6458
6459    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6460        self.value += summary.text.len;
6461    }
6462}
6463
6464impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6465    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6466        Ord::cmp(&self.value, &cursor_location.text.len)
6467    }
6468}
6469
6470impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6471    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
6472        Ord::cmp(&Some(self), cursor_location)
6473    }
6474}
6475
6476impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6477    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6478        Ord::cmp(self, &cursor_location.excerpt_locator)
6479    }
6480}
6481
6482impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6483    fn zero(_cx: ()) -> Self {
6484        Default::default()
6485    }
6486
6487    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6488        self.value += summary.text.lines;
6489    }
6490}
6491
6492impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6493    for ExcerptDimension<D>
6494{
6495    fn zero(_: ()) -> Self {
6496        ExcerptDimension(D::default())
6497    }
6498
6499    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6500        self.0.add_assign(&D::from_text_summary(&summary.text))
6501    }
6502}
6503
6504impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6505    fn zero(_cx: ()) -> Self {
6506        Default::default()
6507    }
6508
6509    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6510        *self = Some(&summary.excerpt_locator);
6511    }
6512}
6513
6514impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6515    fn zero(_cx: ()) -> Self {
6516        Default::default()
6517    }
6518
6519    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6520        *self = Some(summary.excerpt_id);
6521    }
6522}
6523
6524#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6525struct ExcerptDimension<T>(T);
6526
6527#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6528struct OutputDimension<T>(T);
6529
6530impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6531    fn zero(_: ()) -> Self {
6532        ExcerptOffset::new(0)
6533    }
6534
6535    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6536        self.value += summary.input.len;
6537    }
6538}
6539
6540impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6541    fn zero(_: ()) -> Self {
6542        ExcerptPoint::new(0, 0)
6543    }
6544
6545    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6546        self.value += summary.input.lines;
6547    }
6548}
6549
6550impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6551    for ExcerptDimension<D>
6552{
6553    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
6554        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6555    }
6556}
6557
6558impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6559    for ExcerptDimension<D>
6560{
6561    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6562        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
6563    }
6564}
6565
6566impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6567    fn zero(_: ()) -> Self {
6568        ExcerptDimension(D::default())
6569    }
6570
6571    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6572        self.0.add_assign(&D::from_text_summary(&summary.input))
6573    }
6574}
6575
6576impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6577    for OutputDimension<D>
6578{
6579    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6580        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
6581    }
6582}
6583
6584impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6585    fn zero(_: ()) -> Self {
6586        OutputDimension(D::default())
6587    }
6588
6589    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6590        self.0.add_assign(&D::from_text_summary(&summary.output))
6591    }
6592}
6593
6594impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6595    fn zero(_: ()) -> Self {
6596        TextSummary::default()
6597    }
6598
6599    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6600        *self += summary.output
6601    }
6602}
6603
6604impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6605    fn zero(_: ()) -> Self {
6606        0
6607    }
6608
6609    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6610        *self += summary.output.len
6611    }
6612}
6613
6614impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6615    fn zero(_: ()) -> Self {
6616        Point::new(0, 0)
6617    }
6618
6619    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6620        *self += summary.output.lines
6621    }
6622}
6623
6624impl MultiBufferRows<'_> {
6625    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6626        self.point = Point::new(row, 0);
6627        self.cursor.seek(&self.point);
6628    }
6629}
6630
6631impl Iterator for MultiBufferRows<'_> {
6632    type Item = RowInfo;
6633
6634    fn next(&mut self) -> Option<Self::Item> {
6635        if self.is_empty && self.point.row == 0 {
6636            self.point += Point::new(1, 0);
6637            return Some(RowInfo {
6638                buffer_id: None,
6639                buffer_row: Some(0),
6640                multibuffer_row: Some(MultiBufferRow(0)),
6641                diff_status: None,
6642                expand_info: None,
6643                wrapped_buffer_row: None,
6644            });
6645        }
6646
6647        let mut region = self.cursor.region()?;
6648        while self.point >= region.range.end {
6649            self.cursor.next();
6650            if let Some(next_region) = self.cursor.region() {
6651                region = next_region;
6652            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
6653                let multibuffer_row = MultiBufferRow(self.point.row);
6654                let last_excerpt = self
6655                    .cursor
6656                    .excerpts
6657                    .item()
6658                    .or(self.cursor.excerpts.prev_item())?;
6659                let last_row = last_excerpt
6660                    .range
6661                    .context
6662                    .end
6663                    .to_point(&last_excerpt.buffer)
6664                    .row;
6665
6666                let first_row = last_excerpt
6667                    .range
6668                    .context
6669                    .start
6670                    .to_point(&last_excerpt.buffer)
6671                    .row;
6672
6673                let expand_info = if self.is_singleton {
6674                    None
6675                } else {
6676                    let needs_expand_up = first_row == last_row
6677                        && last_row > 0
6678                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
6679                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
6680
6681                    if needs_expand_up && needs_expand_down {
6682                        Some(ExpandExcerptDirection::UpAndDown)
6683                    } else if needs_expand_up {
6684                        Some(ExpandExcerptDirection::Up)
6685                    } else if needs_expand_down {
6686                        Some(ExpandExcerptDirection::Down)
6687                    } else {
6688                        None
6689                    }
6690                    .map(|direction| ExpandInfo {
6691                        direction,
6692                        excerpt_id: last_excerpt.id,
6693                    })
6694                };
6695                self.point += Point::new(1, 0);
6696                return Some(RowInfo {
6697                    buffer_id: Some(last_excerpt.buffer_id),
6698                    buffer_row: Some(last_row),
6699                    multibuffer_row: Some(multibuffer_row),
6700                    diff_status: None,
6701                    wrapped_buffer_row: None,
6702                    expand_info,
6703                });
6704            } else {
6705                return None;
6706            };
6707        }
6708
6709        let overshoot = self.point - region.range.start;
6710        let buffer_point = region.buffer_range.start + overshoot;
6711        let expand_info = if self.is_singleton {
6712            None
6713        } else {
6714            let needs_expand_up = self.point.row == region.range.start.row
6715                && self.cursor.is_at_start_of_excerpt()
6716                && buffer_point.row > 0;
6717            let needs_expand_down = (region.excerpt.has_trailing_newline
6718                && self.point.row + 1 == region.range.end.row
6719                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
6720                && self.cursor.is_at_end_of_excerpt()
6721                && buffer_point.row < region.buffer.max_point().row;
6722
6723            if needs_expand_up && needs_expand_down {
6724                Some(ExpandExcerptDirection::UpAndDown)
6725            } else if needs_expand_up {
6726                Some(ExpandExcerptDirection::Up)
6727            } else if needs_expand_down {
6728                Some(ExpandExcerptDirection::Down)
6729            } else {
6730                None
6731            }
6732            .map(|direction| ExpandInfo {
6733                direction,
6734                excerpt_id: region.excerpt.id,
6735            })
6736        };
6737
6738        let result = Some(RowInfo {
6739            buffer_id: Some(region.buffer.remote_id()),
6740            buffer_row: Some(buffer_point.row),
6741            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6742            diff_status: region
6743                .diff_hunk_status
6744                .filter(|_| self.point < region.range.end),
6745            expand_info,
6746            wrapped_buffer_row: None,
6747        });
6748        self.point += Point::new(1, 0);
6749        result
6750    }
6751}
6752
6753impl<'a> MultiBufferChunks<'a> {
6754    pub fn offset(&self) -> usize {
6755        self.range.start
6756    }
6757
6758    pub fn seek(&mut self, range: Range<usize>) {
6759        self.diff_transforms.seek(&range.end, Bias::Right);
6760        let mut excerpt_end = self.diff_transforms.start().1;
6761        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6762            let overshoot = range.end - self.diff_transforms.start().0;
6763            excerpt_end.value += overshoot;
6764        }
6765
6766        self.diff_transforms.seek(&range.start, Bias::Right);
6767        let mut excerpt_start = self.diff_transforms.start().1;
6768        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6769            let overshoot = range.start - self.diff_transforms.start().0;
6770            excerpt_start.value += overshoot;
6771        }
6772
6773        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6774        self.buffer_chunk.take();
6775        self.range = range;
6776    }
6777
6778    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6779        self.excerpt_offset_range = new_range.clone();
6780        self.excerpts.seek(&new_range.start, Bias::Right);
6781        if let Some(excerpt) = self.excerpts.item() {
6782            let excerpt_start = *self.excerpts.start();
6783            if let Some(excerpt_chunks) = self
6784                .excerpt_chunks
6785                .as_mut()
6786                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6787            {
6788                excerpt.seek_chunks(
6789                    excerpt_chunks,
6790                    (self.excerpt_offset_range.start - excerpt_start).value
6791                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6792                );
6793            } else {
6794                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6795                    (self.excerpt_offset_range.start - excerpt_start).value
6796                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6797                    self.language_aware,
6798                ));
6799            }
6800        } else {
6801            self.excerpt_chunks = None;
6802        }
6803    }
6804
6805    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6806        loop {
6807            if self.excerpt_offset_range.is_empty() {
6808                return None;
6809            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6810                self.excerpt_offset_range.start.value += chunk.text.len();
6811                return Some(chunk);
6812            } else {
6813                self.excerpts.next();
6814                let excerpt = self.excerpts.item()?;
6815                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6816                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6817                    self.language_aware,
6818                ));
6819            }
6820        }
6821    }
6822}
6823
6824impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6825    type Item = &'a str;
6826
6827    fn next(&mut self) -> Option<Self::Item> {
6828        let mut region = self.cursor.region()?;
6829        if self.offset == region.range.start {
6830            self.cursor.prev();
6831            region = self.cursor.region()?;
6832            let start_overshoot = self.start.saturating_sub(region.range.start);
6833            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6834                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6835            ));
6836        }
6837
6838        if self.offset == region.range.end && region.has_trailing_newline {
6839            self.offset -= 1;
6840            Some("\n")
6841        } else {
6842            let chunk = self.current_chunks.as_mut().unwrap().next()?;
6843            self.offset -= chunk.len();
6844            Some(chunk)
6845        }
6846    }
6847}
6848
6849impl<'a> Iterator for MultiBufferChunks<'a> {
6850    type Item = Chunk<'a>;
6851
6852    fn next(&mut self) -> Option<Chunk<'a>> {
6853        if self.range.start >= self.range.end {
6854            return None;
6855        }
6856        if self.range.start == self.diff_transforms.end().0 {
6857            self.diff_transforms.next();
6858        }
6859
6860        let diff_transform_start = self.diff_transforms.start().0;
6861        let diff_transform_end = self.diff_transforms.end().0;
6862        debug_assert!(self.range.start < diff_transform_end);
6863
6864        let diff_transform = self.diff_transforms.item()?;
6865        match diff_transform {
6866            DiffTransform::BufferContent { .. } => {
6867                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6868                    chunk
6869                } else {
6870                    let chunk = self.next_excerpt_chunk().unwrap();
6871                    self.buffer_chunk.insert(chunk)
6872                };
6873
6874                let chunk_end = self.range.start + chunk.text.len();
6875                let diff_transform_end = diff_transform_end.min(self.range.end);
6876
6877                if diff_transform_end < chunk_end {
6878                    let split_idx = diff_transform_end - self.range.start;
6879                    let (before, after) = chunk.text.split_at(split_idx);
6880                    self.range.start = diff_transform_end;
6881                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
6882                    let chars = chunk.chars & mask;
6883                    let tabs = chunk.tabs & mask;
6884
6885                    chunk.text = after;
6886                    chunk.chars = chunk.chars >> split_idx;
6887                    chunk.tabs = chunk.tabs >> split_idx;
6888
6889                    Some(Chunk {
6890                        text: before,
6891                        chars,
6892                        tabs,
6893                        ..chunk.clone()
6894                    })
6895                } else {
6896                    self.range.start = chunk_end;
6897                    self.buffer_chunk.take()
6898                }
6899            }
6900            DiffTransform::DeletedHunk {
6901                buffer_id,
6902                base_text_byte_range,
6903                has_trailing_newline,
6904                ..
6905            } => {
6906                let base_text_start =
6907                    base_text_byte_range.start + self.range.start - diff_transform_start;
6908                let base_text_end =
6909                    base_text_byte_range.start + self.range.end - diff_transform_start;
6910                let base_text_end = base_text_end.min(base_text_byte_range.end);
6911
6912                let mut chunks = if let Some((_, mut chunks)) = self
6913                    .diff_base_chunks
6914                    .take()
6915                    .filter(|(id, _)| id == buffer_id)
6916                {
6917                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
6918                    {
6919                        chunks.seek(base_text_start..base_text_end);
6920                    }
6921                    chunks
6922                } else {
6923                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
6924                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
6925                };
6926
6927                let chunk = if let Some(chunk) = chunks.next() {
6928                    self.range.start += chunk.text.len();
6929                    self.diff_base_chunks = Some((*buffer_id, chunks));
6930                    chunk
6931                } else {
6932                    debug_assert!(has_trailing_newline);
6933                    self.range.start += "\n".len();
6934                    Chunk {
6935                        text: "\n",
6936                        chars: 1u128,
6937                        ..Default::default()
6938                    }
6939                };
6940                Some(chunk)
6941            }
6942        }
6943    }
6944}
6945
6946impl MultiBufferBytes<'_> {
6947    fn consume(&mut self, len: usize) {
6948        self.range.start += len;
6949        self.chunk = &self.chunk[len..];
6950
6951        if !self.range.is_empty() && self.chunk.is_empty() {
6952            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
6953                self.chunk = chunk;
6954            } else if self.has_trailing_newline {
6955                self.has_trailing_newline = false;
6956                self.chunk = b"\n";
6957            } else {
6958                self.cursor.next();
6959                if let Some(region) = self.cursor.region() {
6960                    let mut excerpt_bytes = region.buffer.bytes_in_range(
6961                        region.buffer_range.start
6962                            ..(region.buffer_range.start + self.range.end - region.range.start)
6963                                .min(region.buffer_range.end),
6964                    );
6965                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
6966                    self.excerpt_bytes = Some(excerpt_bytes);
6967                    self.has_trailing_newline =
6968                        region.has_trailing_newline && self.range.end >= region.range.end;
6969                    if self.chunk.is_empty() && self.has_trailing_newline {
6970                        self.has_trailing_newline = false;
6971                        self.chunk = b"\n";
6972                    }
6973                }
6974            }
6975        }
6976    }
6977}
6978
6979impl<'a> Iterator for MultiBufferBytes<'a> {
6980    type Item = &'a [u8];
6981
6982    fn next(&mut self) -> Option<Self::Item> {
6983        let chunk = self.chunk;
6984        if chunk.is_empty() {
6985            None
6986        } else {
6987            self.consume(chunk.len());
6988            Some(chunk)
6989        }
6990    }
6991}
6992
6993impl io::Read for MultiBufferBytes<'_> {
6994    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
6995        let len = cmp::min(buf.len(), self.chunk.len());
6996        buf[..len].copy_from_slice(&self.chunk[..len]);
6997        if len > 0 {
6998            self.consume(len);
6999        }
7000        Ok(len)
7001    }
7002}
7003
7004impl io::Read for ReversedMultiBufferBytes<'_> {
7005    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7006        let len = cmp::min(buf.len(), self.chunk.len());
7007        buf[..len].copy_from_slice(&self.chunk[..len]);
7008        buf[..len].reverse();
7009        if len > 0 {
7010            self.range.end -= len;
7011            self.chunk = &self.chunk[..self.chunk.len() - len];
7012            if !self.range.is_empty()
7013                && self.chunk.is_empty()
7014                && let Some(chunk) = self.chunks.next()
7015            {
7016                self.chunk = chunk.as_bytes();
7017            }
7018        }
7019        Ok(len)
7020    }
7021}
7022
7023impl<'a> Iterator for ExcerptChunks<'a> {
7024    type Item = Chunk<'a>;
7025
7026    fn next(&mut self) -> Option<Self::Item> {
7027        if let Some(chunk) = self.content_chunks.next() {
7028            return Some(chunk);
7029        }
7030
7031        if self.has_footer {
7032            let text = "\n";
7033            let chars = 0b1;
7034            self.has_footer = false;
7035            return Some(Chunk {
7036                text,
7037                chars,
7038                ..Default::default()
7039            });
7040        }
7041
7042        None
7043    }
7044}
7045
7046impl ToOffset for Point {
7047    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7048        snapshot.point_to_offset(*self)
7049    }
7050    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7051        snapshot.point_to_offset_utf16(*self)
7052    }
7053}
7054
7055impl ToOffset for usize {
7056    #[track_caller]
7057    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7058        assert!(
7059            *self <= snapshot.len(),
7060            "offset {} is greater than the snapshot.len() {}",
7061            *self,
7062            snapshot.len(),
7063        );
7064        *self
7065    }
7066    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7067        snapshot.offset_to_offset_utf16(*self)
7068    }
7069}
7070
7071impl ToOffset for OffsetUtf16 {
7072    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7073        snapshot.offset_utf16_to_offset(*self)
7074    }
7075
7076    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7077        *self
7078    }
7079}
7080
7081impl ToOffset for PointUtf16 {
7082    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7083        snapshot.point_utf16_to_offset(*self)
7084    }
7085    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7086        snapshot.point_utf16_to_offset_utf16(*self)
7087    }
7088}
7089
7090impl ToPoint for usize {
7091    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7092        snapshot.offset_to_point(*self)
7093    }
7094    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7095        snapshot.offset_to_point_utf16(*self)
7096    }
7097}
7098
7099impl ToPoint for Point {
7100    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7101        *self
7102    }
7103    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7104        snapshot.point_to_point_utf16(*self)
7105    }
7106}
7107
7108impl ToPoint for PointUtf16 {
7109    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7110        snapshot.point_utf16_to_point(*self)
7111    }
7112    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7113        *self
7114    }
7115}
7116
7117impl From<ExcerptId> for EntityId {
7118    fn from(id: ExcerptId) -> Self {
7119        EntityId::from(id.0 as u64)
7120    }
7121}
7122
7123#[cfg(debug_assertions)]
7124pub mod debug {
7125    use super::*;
7126
7127    pub trait ToMultiBufferDebugRanges {
7128        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
7129        -> Vec<Range<usize>>;
7130    }
7131
7132    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7133        fn to_multi_buffer_debug_ranges(
7134            &self,
7135            snapshot: &MultiBufferSnapshot,
7136        ) -> Vec<Range<usize>> {
7137            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7138        }
7139    }
7140
7141    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
7142        fn to_multi_buffer_debug_ranges(
7143            &self,
7144            snapshot: &MultiBufferSnapshot,
7145        ) -> Vec<Range<usize>> {
7146            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
7147                .to_multi_buffer_debug_ranges(snapshot)
7148        }
7149    }
7150
7151    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
7152        fn to_multi_buffer_debug_ranges(
7153            &self,
7154            snapshot: &MultiBufferSnapshot,
7155        ) -> Vec<Range<usize>> {
7156            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7157        }
7158    }
7159
7160    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
7161        fn to_multi_buffer_debug_ranges(
7162            &self,
7163            snapshot: &MultiBufferSnapshot,
7164        ) -> Vec<Range<usize>> {
7165            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7166        }
7167    }
7168
7169    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
7170        fn to_multi_buffer_debug_ranges(
7171            &self,
7172            snapshot: &MultiBufferSnapshot,
7173        ) -> Vec<Range<usize>> {
7174            self.iter()
7175                .map(|item| {
7176                    let offset = item.to_offset(snapshot);
7177                    offset..offset
7178                })
7179                .collect()
7180        }
7181    }
7182
7183    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
7184        fn to_multi_buffer_debug_ranges(
7185            &self,
7186            snapshot: &MultiBufferSnapshot,
7187        ) -> Vec<Range<usize>> {
7188            self.iter()
7189                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
7190                .collect()
7191        }
7192    }
7193}