multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{Result, anyhow};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  17use itertools::Itertools;
  18use language::{
  19    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  20    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  21    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  22    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  23    Unclipped,
  24    language_settings::{IndentGuideSettings, LanguageSettings, language_settings},
  25};
  26
  27use rope::DimensionPair;
  28use smallvec::SmallVec;
  29use smol::future::yield_now;
  30use std::{
  31    any::type_name,
  32    borrow::Cow,
  33    cell::{Cell, Ref, RefCell},
  34    cmp, fmt,
  35    future::Future,
  36    io,
  37    iter::{self, FromIterator},
  38    mem,
  39    ops::{Range, RangeBounds, Sub},
  40    path::{Path, PathBuf},
  41    rc::Rc,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, Summary, TreeMap};
  47use text::{
  48    BufferId, Edit, LineIndent, TextSummary,
  49    locator::Locator,
  50    subscription::{Subscription, Topic},
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  72    diffs: HashMap<BufferId, DiffState>,
  73    // all_diff_hunks_expanded: bool,
  74    subscriptions: Topic,
  75    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  76    singleton: bool,
  77    history: History,
  78    title: Option<String>,
  79    capability: Capability,
  80    buffer_changed_since_sync: Rc<Cell<bool>>,
  81}
  82
  83#[derive(Clone, Debug, PartialEq, Eq)]
  84pub enum Event {
  85    ExcerptsAdded {
  86        buffer: Entity<Buffer>,
  87        predecessor: ExcerptId,
  88        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  89    },
  90    ExcerptsRemoved {
  91        ids: Vec<ExcerptId>,
  92        removed_buffer_ids: Vec<BufferId>,
  93    },
  94    ExcerptsExpanded {
  95        ids: Vec<ExcerptId>,
  96    },
  97    ExcerptsEdited {
  98        excerpt_ids: Vec<ExcerptId>,
  99        buffer_ids: Vec<BufferId>,
 100    },
 101    DiffHunksToggled,
 102    Edited {
 103        singleton_buffer_edited: bool,
 104        edited_buffer: Option<Entity<Buffer>>,
 105    },
 106    TransactionUndone {
 107        transaction_id: TransactionId,
 108    },
 109    Reloaded,
 110    LanguageChanged(BufferId),
 111    Reparsed(BufferId),
 112    Saved,
 113    FileHandleChanged,
 114    DirtyChanged,
 115    DiagnosticsUpdated,
 116    BufferDiffChanged,
 117}
 118
 119/// A diff hunk, representing a range of consequent lines in a multibuffer.
 120#[derive(Debug, Clone, PartialEq, Eq)]
 121pub struct MultiBufferDiffHunk {
 122    /// The row range in the multibuffer where this diff hunk appears.
 123    pub row_range: Range<MultiBufferRow>,
 124    /// The buffer ID that this hunk belongs to.
 125    pub buffer_id: BufferId,
 126    /// The range of the underlying buffer that this hunk corresponds to.
 127    pub buffer_range: Range<text::Anchor>,
 128    /// The excerpt that contains the diff hunk.
 129    pub excerpt_id: ExcerptId,
 130    /// The range within the buffer's diff base that this hunk corresponds to.
 131    pub diff_base_byte_range: Range<usize>,
 132    /// Whether or not this hunk also appears in the 'secondary diff'.
 133    pub secondary_status: DiffHunkSecondaryStatus,
 134}
 135
 136impl MultiBufferDiffHunk {
 137    pub fn status(&self) -> DiffHunkStatus {
 138        let kind = if self.buffer_range.start == self.buffer_range.end {
 139            DiffHunkStatusKind::Deleted
 140        } else if self.diff_base_byte_range.is_empty() {
 141            DiffHunkStatusKind::Added
 142        } else {
 143            DiffHunkStatusKind::Modified
 144        };
 145        DiffHunkStatus {
 146            kind,
 147            secondary: self.secondary_status,
 148        }
 149    }
 150
 151    pub fn is_created_file(&self) -> bool {
 152        self.diff_base_byte_range == (0..0)
 153            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 154    }
 155
 156    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 157        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 158        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 159        start..end
 160    }
 161}
 162
 163#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 164pub struct PathKey {
 165    namespace: u32,
 166    path: Arc<Path>,
 167}
 168
 169impl PathKey {
 170    pub fn namespaced(namespace: u32, path: Arc<Path>) -> Self {
 171        Self { namespace, path }
 172    }
 173
 174    pub fn for_buffer(buffer: &Entity<Buffer>, cx: &App) -> Self {
 175        if let Some(file) = buffer.read(cx).file() {
 176            Self::namespaced(1, Arc::from(file.full_path(cx)))
 177        } else {
 178            Self::namespaced(0, Arc::from(PathBuf::from(buffer.entity_id().to_string())))
 179        }
 180    }
 181
 182    pub fn path(&self) -> &Arc<Path> {
 183        &self.path
 184    }
 185}
 186
 187pub type MultiBufferPoint = Point;
 188type ExcerptOffset = TypedOffset<Excerpt>;
 189type ExcerptPoint = TypedPoint<Excerpt>;
 190
 191#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 192#[serde(transparent)]
 193pub struct MultiBufferRow(pub u32);
 194
 195impl MultiBufferRow {
 196    pub const MIN: Self = Self(0);
 197    pub const MAX: Self = Self(u32::MAX);
 198}
 199
 200impl std::ops::Add<usize> for MultiBufferRow {
 201    type Output = Self;
 202
 203    fn add(self, rhs: usize) -> Self::Output {
 204        MultiBufferRow(self.0 + rhs as u32)
 205    }
 206}
 207
 208#[derive(Clone)]
 209struct History {
 210    next_transaction_id: TransactionId,
 211    undo_stack: Vec<Transaction>,
 212    redo_stack: Vec<Transaction>,
 213    transaction_depth: usize,
 214    group_interval: Duration,
 215}
 216
 217#[derive(Clone)]
 218struct Transaction {
 219    id: TransactionId,
 220    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 221    first_edit_at: Instant,
 222    last_edit_at: Instant,
 223    suppress_grouping: bool,
 224}
 225
 226pub trait ToOffset: 'static + fmt::Debug {
 227    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 228}
 229
 230pub trait ToOffsetUtf16: 'static + fmt::Debug {
 231    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 232}
 233
 234pub trait ToPoint: 'static + fmt::Debug {
 235    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 236}
 237
 238pub trait ToPointUtf16: 'static + fmt::Debug {
 239    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 240}
 241
 242struct BufferState {
 243    buffer: Entity<Buffer>,
 244    last_version: clock::Global,
 245    last_non_text_state_update_count: usize,
 246    excerpts: Vec<Locator>,
 247    _subscriptions: [gpui::Subscription; 2],
 248}
 249
 250struct DiffState {
 251    diff: Entity<BufferDiff>,
 252    _subscription: gpui::Subscription,
 253}
 254
 255impl DiffState {
 256    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 257        DiffState {
 258            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 259                BufferDiffEvent::DiffChanged { changed_range } => {
 260                    if let Some(changed_range) = changed_range.clone() {
 261                        this.buffer_diff_changed(diff, changed_range, cx)
 262                    }
 263                    cx.emit(Event::BufferDiffChanged);
 264                }
 265                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 266                _ => {}
 267            }),
 268            diff,
 269        }
 270    }
 271}
 272
 273/// The contents of a [`MultiBuffer`] at a single point in time.
 274#[derive(Clone, Default)]
 275pub struct MultiBufferSnapshot {
 276    singleton: bool,
 277    excerpts: SumTree<Excerpt>,
 278    excerpt_ids: SumTree<ExcerptIdMapping>,
 279    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 280    diff_transforms: SumTree<DiffTransform>,
 281    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 282    trailing_excerpt_update_count: usize,
 283    all_diff_hunks_expanded: bool,
 284    non_text_state_update_count: usize,
 285    edit_count: usize,
 286    is_dirty: bool,
 287    has_deleted_file: bool,
 288    has_conflict: bool,
 289    show_headers: bool,
 290}
 291
 292#[derive(Debug, Clone)]
 293enum DiffTransform {
 294    BufferContent {
 295        summary: TextSummary,
 296        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 297    },
 298    DeletedHunk {
 299        summary: TextSummary,
 300        buffer_id: BufferId,
 301        hunk_info: DiffTransformHunkInfo,
 302        base_text_byte_range: Range<usize>,
 303        has_trailing_newline: bool,
 304    },
 305}
 306
 307#[derive(Clone, Copy, Debug)]
 308struct DiffTransformHunkInfo {
 309    excerpt_id: ExcerptId,
 310    hunk_start_anchor: text::Anchor,
 311    hunk_secondary_status: DiffHunkSecondaryStatus,
 312}
 313
 314impl Eq for DiffTransformHunkInfo {}
 315
 316impl PartialEq for DiffTransformHunkInfo {
 317    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 318        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 319    }
 320}
 321
 322impl std::hash::Hash for DiffTransformHunkInfo {
 323    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 324        self.excerpt_id.hash(state);
 325        self.hunk_start_anchor.hash(state);
 326    }
 327}
 328
 329#[derive(Clone)]
 330pub struct ExcerptInfo {
 331    pub id: ExcerptId,
 332    pub buffer: BufferSnapshot,
 333    pub buffer_id: BufferId,
 334    pub range: ExcerptRange<text::Anchor>,
 335    pub end_row: MultiBufferRow,
 336}
 337
 338impl std::fmt::Debug for ExcerptInfo {
 339    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 340        f.debug_struct(type_name::<Self>())
 341            .field("id", &self.id)
 342            .field("buffer_id", &self.buffer_id)
 343            .field("path", &self.buffer.file().map(|f| f.path()))
 344            .field("range", &self.range)
 345            .finish()
 346    }
 347}
 348
 349/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 350#[derive(Debug)]
 351pub struct ExcerptBoundary {
 352    pub prev: Option<ExcerptInfo>,
 353    pub next: ExcerptInfo,
 354    /// The row in the `MultiBuffer` where the boundary is located
 355    pub row: MultiBufferRow,
 356}
 357
 358impl ExcerptBoundary {
 359    pub fn starts_new_buffer(&self) -> bool {
 360        match (self.prev.as_ref(), &self.next) {
 361            (None, _) => true,
 362            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 363        }
 364    }
 365}
 366
 367#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 368pub struct ExpandInfo {
 369    pub direction: ExpandExcerptDirection,
 370    pub excerpt_id: ExcerptId,
 371}
 372
 373#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 374pub struct RowInfo {
 375    pub buffer_id: Option<BufferId>,
 376    pub buffer_row: Option<u32>,
 377    pub multibuffer_row: Option<MultiBufferRow>,
 378    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 379    pub expand_info: Option<ExpandInfo>,
 380}
 381
 382/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 383#[derive(Clone)]
 384struct Excerpt {
 385    /// The unique identifier for this excerpt
 386    id: ExcerptId,
 387    /// The location of the excerpt in the [`MultiBuffer`]
 388    locator: Locator,
 389    /// The buffer being excerpted
 390    buffer_id: BufferId,
 391    /// A snapshot of the buffer being excerpted
 392    buffer: BufferSnapshot,
 393    /// The range of the buffer to be shown in the excerpt
 394    range: ExcerptRange<text::Anchor>,
 395    /// The last row in the excerpted slice of the buffer
 396    max_buffer_row: BufferRow,
 397    /// A summary of the text in the excerpt
 398    text_summary: TextSummary,
 399    has_trailing_newline: bool,
 400}
 401
 402/// A public view into an `Excerpt` in a [`MultiBuffer`].
 403///
 404/// Contains methods for getting the [`Buffer`] of the excerpt,
 405/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 406#[derive(Clone)]
 407pub struct MultiBufferExcerpt<'a> {
 408    excerpt: &'a Excerpt,
 409    diff_transforms: sum_tree::Cursor<'a, DiffTransform, DiffTransforms<usize>>,
 410    offset: usize,
 411    excerpt_offset: ExcerptDimension<usize>,
 412    buffer_offset: usize,
 413}
 414
 415#[derive(Clone, Debug)]
 416struct ExcerptIdMapping {
 417    id: ExcerptId,
 418    locator: Locator,
 419}
 420
 421/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 422/// These ranges are relative to the buffer itself
 423#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 424pub struct ExcerptRange<T> {
 425    /// The full range of text to be shown in the excerpt.
 426    pub context: Range<T>,
 427    /// The primary range of text to be highlighted in the excerpt.
 428    /// In a multi-buffer search, this would be the text that matched the search
 429    pub primary: Range<T>,
 430}
 431
 432impl<T: Clone> ExcerptRange<T> {
 433    pub fn new(context: Range<T>) -> Self {
 434        Self {
 435            context: context.clone(),
 436            primary: context,
 437        }
 438    }
 439}
 440
 441#[derive(Clone, Debug, Default)]
 442pub struct ExcerptSummary {
 443    excerpt_id: ExcerptId,
 444    /// The location of the last [`Excerpt`] being summarized
 445    excerpt_locator: Locator,
 446    widest_line_number: u32,
 447    text: TextSummary,
 448}
 449
 450#[derive(Debug, Clone)]
 451pub struct DiffTransformSummary {
 452    input: TextSummary,
 453    output: TextSummary,
 454}
 455
 456#[derive(Clone)]
 457pub struct MultiBufferRows<'a> {
 458    point: Point,
 459    is_empty: bool,
 460    is_singleton: bool,
 461    cursor: MultiBufferCursor<'a, Point>,
 462}
 463
 464pub struct MultiBufferChunks<'a> {
 465    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 466    diff_transforms: Cursor<'a, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 467    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 468    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 469    buffer_chunk: Option<Chunk<'a>>,
 470    range: Range<usize>,
 471    excerpt_offset_range: Range<ExcerptOffset>,
 472    excerpt_chunks: Option<ExcerptChunks<'a>>,
 473    language_aware: bool,
 474}
 475
 476pub struct ReversedMultiBufferChunks<'a> {
 477    cursor: MultiBufferCursor<'a, usize>,
 478    current_chunks: Option<rope::Chunks<'a>>,
 479    start: usize,
 480    offset: usize,
 481}
 482
 483pub struct MultiBufferBytes<'a> {
 484    range: Range<usize>,
 485    cursor: MultiBufferCursor<'a, usize>,
 486    excerpt_bytes: Option<text::Bytes<'a>>,
 487    has_trailing_newline: bool,
 488    chunk: &'a [u8],
 489}
 490
 491pub struct ReversedMultiBufferBytes<'a> {
 492    range: Range<usize>,
 493    chunks: ReversedMultiBufferChunks<'a>,
 494    chunk: &'a [u8],
 495}
 496
 497#[derive(Clone)]
 498struct DiffTransforms<D> {
 499    output_dimension: OutputDimension<D>,
 500    excerpt_dimension: ExcerptDimension<D>,
 501}
 502
 503impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 504    fn zero(cx: &<DiffTransformSummary as sum_tree::Summary>::Context) -> Self {
 505        Self {
 506            output_dimension: OutputDimension::zero(cx),
 507            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 508                cx,
 509            ),
 510        }
 511    }
 512
 513    fn add_summary(
 514        &mut self,
 515        summary: &'a DiffTransformSummary,
 516        cx: &<DiffTransformSummary as sum_tree::Summary>::Context,
 517    ) {
 518        self.output_dimension.add_summary(summary, cx);
 519        self.excerpt_dimension.add_summary(summary, cx);
 520    }
 521}
 522
 523#[derive(Clone)]
 524struct MultiBufferCursor<'a, D: TextDimension> {
 525    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 526    diff_transforms: Cursor<'a, DiffTransform, DiffTransforms<D>>,
 527    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 528    cached_region: Option<MultiBufferRegion<'a, D>>,
 529}
 530
 531#[derive(Clone)]
 532struct MultiBufferRegion<'a, D: TextDimension> {
 533    buffer: &'a BufferSnapshot,
 534    is_main_buffer: bool,
 535    diff_hunk_status: Option<DiffHunkStatus>,
 536    excerpt: &'a Excerpt,
 537    buffer_range: Range<D>,
 538    range: Range<D>,
 539    has_trailing_newline: bool,
 540}
 541
 542struct ExcerptChunks<'a> {
 543    excerpt_id: ExcerptId,
 544    content_chunks: BufferChunks<'a>,
 545    footer_height: usize,
 546}
 547
 548#[derive(Debug)]
 549struct BufferEdit {
 550    range: Range<usize>,
 551    new_text: Arc<str>,
 552    is_insertion: bool,
 553    original_indent_column: Option<u32>,
 554    excerpt_id: ExcerptId,
 555}
 556
 557#[derive(Clone, Copy, Debug, PartialEq)]
 558enum DiffChangeKind {
 559    BufferEdited,
 560    DiffUpdated { base_changed: bool },
 561    ExpandOrCollapseHunks { expand: bool },
 562}
 563
 564#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 565pub enum ExpandExcerptDirection {
 566    Up,
 567    Down,
 568    UpAndDown,
 569}
 570
 571impl ExpandExcerptDirection {
 572    pub fn should_expand_up(&self) -> bool {
 573        match self {
 574            ExpandExcerptDirection::Up => true,
 575            ExpandExcerptDirection::Down => false,
 576            ExpandExcerptDirection::UpAndDown => true,
 577        }
 578    }
 579
 580    pub fn should_expand_down(&self) -> bool {
 581        match self {
 582            ExpandExcerptDirection::Up => false,
 583            ExpandExcerptDirection::Down => true,
 584            ExpandExcerptDirection::UpAndDown => true,
 585        }
 586    }
 587}
 588
 589#[derive(Clone, Debug, PartialEq)]
 590pub struct IndentGuide {
 591    pub buffer_id: BufferId,
 592    pub start_row: MultiBufferRow,
 593    pub end_row: MultiBufferRow,
 594    pub depth: u32,
 595    pub tab_size: u32,
 596    pub settings: IndentGuideSettings,
 597}
 598
 599impl IndentGuide {
 600    pub fn indent_level(&self) -> u32 {
 601        self.depth * self.tab_size
 602    }
 603}
 604
 605impl MultiBuffer {
 606    pub fn new(capability: Capability) -> Self {
 607        Self {
 608            snapshot: RefCell::new(MultiBufferSnapshot {
 609                show_headers: true,
 610                ..MultiBufferSnapshot::default()
 611            }),
 612            buffers: RefCell::default(),
 613            diffs: HashMap::default(),
 614            subscriptions: Topic::default(),
 615            singleton: false,
 616            capability,
 617            title: None,
 618            excerpts_by_path: Default::default(),
 619            paths_by_excerpt: Default::default(),
 620            buffer_changed_since_sync: Default::default(),
 621            history: History {
 622                next_transaction_id: clock::Lamport::default(),
 623                undo_stack: Vec::new(),
 624                redo_stack: Vec::new(),
 625                transaction_depth: 0,
 626                group_interval: Duration::from_millis(300),
 627            },
 628        }
 629    }
 630
 631    pub fn without_headers(capability: Capability) -> Self {
 632        Self {
 633            snapshot: Default::default(),
 634            buffers: Default::default(),
 635            excerpts_by_path: Default::default(),
 636            paths_by_excerpt: Default::default(),
 637            diffs: HashMap::default(),
 638            subscriptions: Default::default(),
 639            singleton: false,
 640            capability,
 641            buffer_changed_since_sync: Default::default(),
 642            history: History {
 643                next_transaction_id: Default::default(),
 644                undo_stack: Default::default(),
 645                redo_stack: Default::default(),
 646                transaction_depth: 0,
 647                group_interval: Duration::from_millis(300),
 648            },
 649            title: Default::default(),
 650        }
 651    }
 652
 653    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 654        let mut buffers = HashMap::default();
 655        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 656        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 657            buffer_state.buffer.update(new_cx, |buffer, _| {
 658                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 659            });
 660            buffers.insert(
 661                *buffer_id,
 662                BufferState {
 663                    buffer: buffer_state.buffer.clone(),
 664                    last_version: buffer_state.last_version.clone(),
 665                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 666                    excerpts: buffer_state.excerpts.clone(),
 667                    _subscriptions: [
 668                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 669                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 670                    ],
 671                },
 672            );
 673        }
 674        let mut diff_bases = HashMap::default();
 675        for (buffer_id, diff) in self.diffs.iter() {
 676            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 677        }
 678        Self {
 679            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 680            buffers: RefCell::new(buffers),
 681            excerpts_by_path: Default::default(),
 682            paths_by_excerpt: Default::default(),
 683            diffs: diff_bases,
 684            subscriptions: Default::default(),
 685            singleton: self.singleton,
 686            capability: self.capability,
 687            history: self.history.clone(),
 688            title: self.title.clone(),
 689            buffer_changed_since_sync,
 690        }
 691    }
 692
 693    pub fn with_title(mut self, title: String) -> Self {
 694        self.title = Some(title);
 695        self
 696    }
 697
 698    pub fn read_only(&self) -> bool {
 699        self.capability == Capability::ReadOnly
 700    }
 701
 702    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 703        let mut this = Self::new(buffer.read(cx).capability());
 704        this.singleton = true;
 705        this.push_excerpts(
 706            buffer,
 707            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 708            cx,
 709        );
 710        this.snapshot.borrow_mut().singleton = true;
 711        this
 712    }
 713
 714    /// Returns an up-to-date snapshot of the MultiBuffer.
 715    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 716        self.sync(cx);
 717        self.snapshot.borrow().clone()
 718    }
 719
 720    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 721        self.sync(cx);
 722        self.snapshot.borrow()
 723    }
 724
 725    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 726        if self.singleton {
 727            Some(
 728                self.buffers
 729                    .borrow()
 730                    .values()
 731                    .next()
 732                    .unwrap()
 733                    .buffer
 734                    .clone(),
 735            )
 736        } else {
 737            None
 738        }
 739    }
 740
 741    pub fn is_singleton(&self) -> bool {
 742        self.singleton
 743    }
 744
 745    pub fn subscribe(&mut self) -> Subscription {
 746        self.subscriptions.subscribe()
 747    }
 748
 749    pub fn is_dirty(&self, cx: &App) -> bool {
 750        self.read(cx).is_dirty()
 751    }
 752
 753    pub fn has_deleted_file(&self, cx: &App) -> bool {
 754        self.read(cx).has_deleted_file()
 755    }
 756
 757    pub fn has_conflict(&self, cx: &App) -> bool {
 758        self.read(cx).has_conflict()
 759    }
 760
 761    // The `is_empty` signature doesn't match what clippy expects
 762    #[allow(clippy::len_without_is_empty)]
 763    pub fn len(&self, cx: &App) -> usize {
 764        self.read(cx).len()
 765    }
 766
 767    pub fn is_empty(&self) -> bool {
 768        self.buffers.borrow().is_empty()
 769    }
 770
 771    pub fn symbols_containing<T: ToOffset>(
 772        &self,
 773        offset: T,
 774        theme: Option<&SyntaxTheme>,
 775        cx: &App,
 776    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 777        self.read(cx).symbols_containing(offset, theme)
 778    }
 779
 780    pub fn edit<I, S, T>(
 781        &self,
 782        edits: I,
 783        autoindent_mode: Option<AutoindentMode>,
 784        cx: &mut Context<Self>,
 785    ) where
 786        I: IntoIterator<Item = (Range<S>, T)>,
 787        S: ToOffset,
 788        T: Into<Arc<str>>,
 789    {
 790        let snapshot = self.read(cx);
 791        let edits = edits
 792            .into_iter()
 793            .map(|(range, new_text)| {
 794                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 795                if range.start > range.end {
 796                    mem::swap(&mut range.start, &mut range.end);
 797                }
 798                (range, new_text.into())
 799            })
 800            .collect::<Vec<_>>();
 801
 802        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 803
 804        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 805        fn edit_internal(
 806            this: &MultiBuffer,
 807            snapshot: Ref<MultiBufferSnapshot>,
 808            edits: Vec<(Range<usize>, Arc<str>)>,
 809            mut autoindent_mode: Option<AutoindentMode>,
 810            cx: &mut Context<MultiBuffer>,
 811        ) {
 812            if this.read_only() || this.buffers.borrow().is_empty() {
 813                return;
 814            }
 815
 816            let original_indent_columns = match &mut autoindent_mode {
 817                Some(AutoindentMode::Block {
 818                    original_indent_columns,
 819                }) => mem::take(original_indent_columns),
 820                _ => Default::default(),
 821            };
 822
 823            let (buffer_edits, edited_excerpt_ids) =
 824                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 825            drop(snapshot);
 826
 827            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 828            for (buffer_id, mut edits) in buffer_edits {
 829                buffer_ids.push(buffer_id);
 830                edits.sort_by_key(|edit| edit.range.start);
 831                this.buffers.borrow()[&buffer_id]
 832                    .buffer
 833                    .update(cx, |buffer, cx| {
 834                        let mut edits = edits.into_iter().peekable();
 835                        let mut insertions = Vec::new();
 836                        let mut original_indent_columns = Vec::new();
 837                        let mut deletions = Vec::new();
 838                        let empty_str: Arc<str> = Arc::default();
 839                        while let Some(BufferEdit {
 840                            mut range,
 841                            mut new_text,
 842                            mut is_insertion,
 843                            original_indent_column,
 844                            excerpt_id,
 845                        }) = edits.next()
 846                        {
 847                            while let Some(BufferEdit {
 848                                range: next_range,
 849                                is_insertion: next_is_insertion,
 850                                new_text: next_new_text,
 851                                excerpt_id: next_excerpt_id,
 852                                ..
 853                            }) = edits.peek()
 854                            {
 855                                if range.end >= next_range.start {
 856                                    range.end = cmp::max(next_range.end, range.end);
 857                                    is_insertion |= *next_is_insertion;
 858                                    if excerpt_id == *next_excerpt_id {
 859                                        new_text = format!("{new_text}{next_new_text}").into();
 860                                    }
 861                                    edits.next();
 862                                } else {
 863                                    break;
 864                                }
 865                            }
 866
 867                            if is_insertion {
 868                                original_indent_columns.push(original_indent_column);
 869                                insertions.push((
 870                                    buffer.anchor_before(range.start)
 871                                        ..buffer.anchor_before(range.end),
 872                                    new_text.clone(),
 873                                ));
 874                            } else if !range.is_empty() {
 875                                deletions.push((
 876                                    buffer.anchor_before(range.start)
 877                                        ..buffer.anchor_before(range.end),
 878                                    empty_str.clone(),
 879                                ));
 880                            }
 881                        }
 882
 883                        let deletion_autoindent_mode =
 884                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 885                                Some(AutoindentMode::Block {
 886                                    original_indent_columns: Default::default(),
 887                                })
 888                            } else {
 889                                autoindent_mode.clone()
 890                            };
 891                        let insertion_autoindent_mode =
 892                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 893                                Some(AutoindentMode::Block {
 894                                    original_indent_columns,
 895                                })
 896                            } else {
 897                                autoindent_mode.clone()
 898                            };
 899
 900                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 901                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 902                    })
 903            }
 904
 905            cx.emit(Event::ExcerptsEdited {
 906                excerpt_ids: edited_excerpt_ids,
 907                buffer_ids,
 908            });
 909        }
 910    }
 911
 912    fn convert_edits_to_buffer_edits(
 913        &self,
 914        edits: Vec<(Range<usize>, Arc<str>)>,
 915        snapshot: &MultiBufferSnapshot,
 916        original_indent_columns: &[Option<u32>],
 917    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 918        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 919        let mut edited_excerpt_ids = Vec::new();
 920        let mut cursor = snapshot.cursor::<usize>();
 921        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 922            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 923
 924            cursor.seek(&range.start);
 925            let mut start_region = cursor.region().expect("start offset out of bounds");
 926            if !start_region.is_main_buffer {
 927                cursor.next();
 928                if let Some(region) = cursor.region() {
 929                    start_region = region;
 930                } else {
 931                    continue;
 932                }
 933            }
 934
 935            if range.end < start_region.range.start {
 936                continue;
 937            }
 938
 939            if range.end > start_region.range.end {
 940                cursor.seek_forward(&range.end);
 941            }
 942            let mut end_region = cursor.region().expect("end offset out of bounds");
 943            if !end_region.is_main_buffer {
 944                cursor.prev();
 945                if let Some(region) = cursor.region() {
 946                    end_region = region;
 947                } else {
 948                    continue;
 949                }
 950            }
 951
 952            if range.start > end_region.range.end {
 953                continue;
 954            }
 955
 956            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 957            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 958            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 959                .min(start_region.buffer_range.end);
 960            let buffer_end =
 961                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 962
 963            if start_region.excerpt.id == end_region.excerpt.id {
 964                if start_region.is_main_buffer {
 965                    edited_excerpt_ids.push(start_region.excerpt.id);
 966                    buffer_edits
 967                        .entry(start_region.buffer.remote_id())
 968                        .or_default()
 969                        .push(BufferEdit {
 970                            range: buffer_start..buffer_end,
 971                            new_text,
 972                            is_insertion: true,
 973                            original_indent_column,
 974                            excerpt_id: start_region.excerpt.id,
 975                        });
 976                }
 977            } else {
 978                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 979                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 980                if start_region.is_main_buffer {
 981                    edited_excerpt_ids.push(start_region.excerpt.id);
 982                    buffer_edits
 983                        .entry(start_region.buffer.remote_id())
 984                        .or_default()
 985                        .push(BufferEdit {
 986                            range: start_excerpt_range,
 987                            new_text: new_text.clone(),
 988                            is_insertion: true,
 989                            original_indent_column,
 990                            excerpt_id: start_region.excerpt.id,
 991                        });
 992                }
 993                if end_region.is_main_buffer {
 994                    edited_excerpt_ids.push(end_region.excerpt.id);
 995                    buffer_edits
 996                        .entry(end_region.buffer.remote_id())
 997                        .or_default()
 998                        .push(BufferEdit {
 999                            range: end_excerpt_range,
1000                            new_text: new_text.clone(),
1001                            is_insertion: false,
1002                            original_indent_column,
1003                            excerpt_id: end_region.excerpt.id,
1004                        });
1005                }
1006
1007                cursor.seek(&range.start);
1008                cursor.next_excerpt();
1009                while let Some(region) = cursor.region() {
1010                    if region.excerpt.id == end_region.excerpt.id {
1011                        break;
1012                    }
1013                    if region.is_main_buffer {
1014                        edited_excerpt_ids.push(region.excerpt.id);
1015                        buffer_edits
1016                            .entry(region.buffer.remote_id())
1017                            .or_default()
1018                            .push(BufferEdit {
1019                                range: region.buffer_range,
1020                                new_text: new_text.clone(),
1021                                is_insertion: false,
1022                                original_indent_column,
1023                                excerpt_id: region.excerpt.id,
1024                            });
1025                    }
1026                    cursor.next_excerpt();
1027                }
1028            }
1029        }
1030        (buffer_edits, edited_excerpt_ids)
1031    }
1032
1033    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1034    where
1035        I: IntoIterator<Item = Range<S>>,
1036        S: ToOffset,
1037    {
1038        let snapshot = self.read(cx);
1039        let empty = Arc::<str>::from("");
1040        let edits = ranges
1041            .into_iter()
1042            .map(|range| {
1043                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1044                if range.start > range.end {
1045                    mem::swap(&mut range.start, &mut range.end);
1046                }
1047                (range, empty.clone())
1048            })
1049            .collect::<Vec<_>>();
1050
1051        return autoindent_ranges_internal(self, snapshot, edits, cx);
1052
1053        fn autoindent_ranges_internal(
1054            this: &MultiBuffer,
1055            snapshot: Ref<MultiBufferSnapshot>,
1056            edits: Vec<(Range<usize>, Arc<str>)>,
1057            cx: &mut Context<MultiBuffer>,
1058        ) {
1059            if this.read_only() || this.buffers.borrow().is_empty() {
1060                return;
1061            }
1062
1063            let (buffer_edits, edited_excerpt_ids) =
1064                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1065            drop(snapshot);
1066
1067            let mut buffer_ids = Vec::new();
1068            for (buffer_id, mut edits) in buffer_edits {
1069                buffer_ids.push(buffer_id);
1070                edits.sort_unstable_by_key(|edit| edit.range.start);
1071
1072                let mut ranges: Vec<Range<usize>> = Vec::new();
1073                for edit in edits {
1074                    if let Some(last_range) = ranges.last_mut()
1075                        && edit.range.start <= last_range.end
1076                    {
1077                        last_range.end = last_range.end.max(edit.range.end);
1078                        continue;
1079                    }
1080                    ranges.push(edit.range);
1081                }
1082
1083                this.buffers.borrow()[&buffer_id]
1084                    .buffer
1085                    .update(cx, |buffer, cx| {
1086                        buffer.autoindent_ranges(ranges, cx);
1087                    })
1088            }
1089
1090            cx.emit(Event::ExcerptsEdited {
1091                excerpt_ids: edited_excerpt_ids,
1092                buffer_ids,
1093            });
1094        }
1095    }
1096
1097    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1098    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1099    // Panics if the given position is invalid.
1100    pub fn insert_empty_line(
1101        &mut self,
1102        position: impl ToPoint,
1103        space_above: bool,
1104        space_below: bool,
1105        cx: &mut Context<Self>,
1106    ) -> Point {
1107        let multibuffer_point = position.to_point(&self.read(cx));
1108        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1109        self.start_transaction(cx);
1110        let empty_line_start = buffer.update(cx, |buffer, cx| {
1111            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1112        });
1113        self.end_transaction(cx);
1114        multibuffer_point + (empty_line_start - buffer_point)
1115    }
1116
1117    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1118        self.start_transaction_at(Instant::now(), cx)
1119    }
1120
1121    pub fn start_transaction_at(
1122        &mut self,
1123        now: Instant,
1124        cx: &mut Context<Self>,
1125    ) -> Option<TransactionId> {
1126        if let Some(buffer) = self.as_singleton() {
1127            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1128        }
1129
1130        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1131            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1132        }
1133        self.history.start_transaction(now)
1134    }
1135
1136    pub fn last_transaction_id(&self, cx: &App) -> Option<TransactionId> {
1137        if let Some(buffer) = self.as_singleton() {
1138            buffer
1139                .read(cx)
1140                .peek_undo_stack()
1141                .map(|history_entry| history_entry.transaction_id())
1142        } else {
1143            let last_transaction = self.history.undo_stack.last()?;
1144            Some(last_transaction.id)
1145        }
1146    }
1147
1148    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1149        self.end_transaction_at(Instant::now(), cx)
1150    }
1151
1152    pub fn end_transaction_at(
1153        &mut self,
1154        now: Instant,
1155        cx: &mut Context<Self>,
1156    ) -> Option<TransactionId> {
1157        if let Some(buffer) = self.as_singleton() {
1158            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1159        }
1160
1161        let mut buffer_transactions = HashMap::default();
1162        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1163            if let Some(transaction_id) =
1164                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1165            {
1166                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1167            }
1168        }
1169
1170        if self.history.end_transaction(now, buffer_transactions) {
1171            let transaction_id = self.history.group().unwrap();
1172            Some(transaction_id)
1173        } else {
1174            None
1175        }
1176    }
1177
1178    pub fn edited_ranges_for_transaction<D>(
1179        &self,
1180        transaction_id: TransactionId,
1181        cx: &App,
1182    ) -> Vec<Range<D>>
1183    where
1184        D: TextDimension + Ord + Sub<D, Output = D>,
1185    {
1186        let Some(transaction) = self.history.transaction(transaction_id) else {
1187            return Vec::new();
1188        };
1189
1190        let mut ranges = Vec::new();
1191        let snapshot = self.read(cx);
1192        let buffers = self.buffers.borrow();
1193        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1194
1195        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1196            let Some(buffer_state) = buffers.get(buffer_id) else {
1197                continue;
1198            };
1199
1200            let buffer = buffer_state.buffer.read(cx);
1201            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1202                for excerpt_id in &buffer_state.excerpts {
1203                    cursor.seek(excerpt_id, Bias::Left);
1204                    if let Some(excerpt) = cursor.item()
1205                        && excerpt.locator == *excerpt_id
1206                    {
1207                        let excerpt_buffer_start = excerpt.range.context.start.summary::<D>(buffer);
1208                        let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1209                        let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1210                        if excerpt_range.contains(&range.start)
1211                            && excerpt_range.contains(&range.end)
1212                        {
1213                            let excerpt_start = D::from_text_summary(&cursor.start().text);
1214
1215                            let mut start = excerpt_start;
1216                            start.add_assign(&(range.start - excerpt_buffer_start));
1217                            let mut end = excerpt_start;
1218                            end.add_assign(&(range.end - excerpt_buffer_start));
1219
1220                            ranges.push(start..end);
1221                            break;
1222                        }
1223                    }
1224                }
1225            }
1226        }
1227
1228        ranges.sort_by_key(|range| range.start);
1229        ranges
1230    }
1231
1232    pub fn merge_transactions(
1233        &mut self,
1234        transaction: TransactionId,
1235        destination: TransactionId,
1236        cx: &mut Context<Self>,
1237    ) {
1238        if let Some(buffer) = self.as_singleton() {
1239            buffer.update(cx, |buffer, _| {
1240                buffer.merge_transactions(transaction, destination)
1241            });
1242        } else if let Some(transaction) = self.history.forget(transaction)
1243            && let Some(destination) = self.history.transaction_mut(destination)
1244        {
1245            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1246                if let Some(destination_buffer_transaction_id) =
1247                    destination.buffer_transactions.get(&buffer_id)
1248                {
1249                    if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1250                        state.buffer.update(cx, |buffer, _| {
1251                            buffer.merge_transactions(
1252                                buffer_transaction_id,
1253                                *destination_buffer_transaction_id,
1254                            )
1255                        });
1256                    }
1257                } else {
1258                    destination
1259                        .buffer_transactions
1260                        .insert(buffer_id, buffer_transaction_id);
1261                }
1262            }
1263        }
1264    }
1265
1266    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1267        self.history.finalize_last_transaction();
1268        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1269            buffer.update(cx, |buffer, _| {
1270                buffer.finalize_last_transaction();
1271            });
1272        }
1273    }
1274
1275    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1276    where
1277        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1278    {
1279        self.history
1280            .push_transaction(buffer_transactions, Instant::now(), cx);
1281        self.history.finalize_last_transaction();
1282    }
1283
1284    pub fn group_until_transaction(
1285        &mut self,
1286        transaction_id: TransactionId,
1287        cx: &mut Context<Self>,
1288    ) {
1289        if let Some(buffer) = self.as_singleton() {
1290            buffer.update(cx, |buffer, _| {
1291                buffer.group_until_transaction(transaction_id)
1292            });
1293        } else {
1294            self.history.group_until(transaction_id);
1295        }
1296    }
1297
1298    pub fn set_active_selections(
1299        &self,
1300        selections: &[Selection<Anchor>],
1301        line_mode: bool,
1302        cursor_shape: CursorShape,
1303        cx: &mut Context<Self>,
1304    ) {
1305        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1306            Default::default();
1307        let snapshot = self.read(cx);
1308        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1309        for selection in selections {
1310            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1311            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1312
1313            cursor.seek(&Some(start_locator), Bias::Left);
1314            while let Some(excerpt) = cursor.item() {
1315                if excerpt.locator > *end_locator {
1316                    break;
1317                }
1318
1319                let mut start = excerpt.range.context.start;
1320                let mut end = excerpt.range.context.end;
1321                if excerpt.id == selection.start.excerpt_id {
1322                    start = selection.start.text_anchor;
1323                }
1324                if excerpt.id == selection.end.excerpt_id {
1325                    end = selection.end.text_anchor;
1326                }
1327                selections_by_buffer
1328                    .entry(excerpt.buffer_id)
1329                    .or_default()
1330                    .push(Selection {
1331                        id: selection.id,
1332                        start,
1333                        end,
1334                        reversed: selection.reversed,
1335                        goal: selection.goal,
1336                    });
1337
1338                cursor.next();
1339            }
1340        }
1341
1342        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1343            if !selections_by_buffer.contains_key(buffer_id) {
1344                buffer_state
1345                    .buffer
1346                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1347            }
1348        }
1349
1350        for (buffer_id, mut selections) in selections_by_buffer {
1351            self.buffers.borrow()[&buffer_id]
1352                .buffer
1353                .update(cx, |buffer, cx| {
1354                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1355                    let mut selections = selections.into_iter().peekable();
1356                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1357                        let mut selection = selections.next()?;
1358                        while let Some(next_selection) = selections.peek() {
1359                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1360                                let next_selection = selections.next().unwrap();
1361                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1362                                    selection.end = next_selection.end;
1363                                }
1364                            } else {
1365                                break;
1366                            }
1367                        }
1368                        Some(selection)
1369                    }));
1370                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1371                });
1372        }
1373    }
1374
1375    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1376        for buffer in self.buffers.borrow().values() {
1377            buffer
1378                .buffer
1379                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1380        }
1381    }
1382
1383    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1384        let mut transaction_id = None;
1385        if let Some(buffer) = self.as_singleton() {
1386            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1387        } else {
1388            while let Some(transaction) = self.history.pop_undo() {
1389                let mut undone = false;
1390                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1391                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1392                        undone |= buffer.update(cx, |buffer, cx| {
1393                            let undo_to = *buffer_transaction_id;
1394                            if let Some(entry) = buffer.peek_undo_stack() {
1395                                *buffer_transaction_id = entry.transaction_id();
1396                            }
1397                            buffer.undo_to_transaction(undo_to, cx)
1398                        });
1399                    }
1400                }
1401
1402                if undone {
1403                    transaction_id = Some(transaction.id);
1404                    break;
1405                }
1406            }
1407        }
1408
1409        if let Some(transaction_id) = transaction_id {
1410            cx.emit(Event::TransactionUndone { transaction_id });
1411        }
1412
1413        transaction_id
1414    }
1415
1416    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1417        if let Some(buffer) = self.as_singleton() {
1418            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1419        }
1420
1421        while let Some(transaction) = self.history.pop_redo() {
1422            let mut redone = false;
1423            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1424                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1425                    redone |= buffer.update(cx, |buffer, cx| {
1426                        let redo_to = *buffer_transaction_id;
1427                        if let Some(entry) = buffer.peek_redo_stack() {
1428                            *buffer_transaction_id = entry.transaction_id();
1429                        }
1430                        buffer.redo_to_transaction(redo_to, cx)
1431                    });
1432                }
1433            }
1434
1435            if redone {
1436                return Some(transaction.id);
1437            }
1438        }
1439
1440        None
1441    }
1442
1443    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1444        if let Some(buffer) = self.as_singleton() {
1445            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1446        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1447            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1448                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1449                    buffer.update(cx, |buffer, cx| {
1450                        buffer.undo_transaction(*transaction_id, cx)
1451                    });
1452                }
1453            }
1454        }
1455    }
1456
1457    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1458        if let Some(buffer) = self.as_singleton() {
1459            buffer.update(cx, |buffer, _| {
1460                buffer.forget_transaction(transaction_id);
1461            });
1462        } else if let Some(transaction) = self.history.forget(transaction_id) {
1463            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1464                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1465                    state.buffer.update(cx, |buffer, _| {
1466                        buffer.forget_transaction(buffer_transaction_id);
1467                    });
1468                }
1469            }
1470        }
1471    }
1472
1473    pub fn push_excerpts<O>(
1474        &mut self,
1475        buffer: Entity<Buffer>,
1476        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1477        cx: &mut Context<Self>,
1478    ) -> Vec<ExcerptId>
1479    where
1480        O: text::ToOffset,
1481    {
1482        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1483    }
1484
1485    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1486        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1487        let snapshot = self.snapshot(cx);
1488        let excerpt = snapshot.excerpt(*excerpt_id)?;
1489        Some(Anchor::in_buffer(
1490            *excerpt_id,
1491            excerpt.buffer_id,
1492            excerpt.range.context.start,
1493        ))
1494    }
1495
1496    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1497        self.excerpts_by_path.keys()
1498    }
1499
1500    fn expand_excerpts_with_paths(
1501        &mut self,
1502        ids: impl IntoIterator<Item = ExcerptId>,
1503        line_count: u32,
1504        direction: ExpandExcerptDirection,
1505        cx: &mut Context<Self>,
1506    ) {
1507        let grouped = ids
1508            .into_iter()
1509            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1510            .into_iter()
1511            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1512            .collect::<Vec<_>>();
1513        let snapshot = self.snapshot(cx);
1514
1515        for (path, ids) in grouped.into_iter() {
1516            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1517                continue;
1518            };
1519
1520            let ids_to_expand = HashSet::from_iter(ids);
1521            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1522                let excerpt = snapshot.excerpt(*excerpt_id)?;
1523
1524                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1525                if ids_to_expand.contains(excerpt_id) {
1526                    match direction {
1527                        ExpandExcerptDirection::Up => {
1528                            context.start.row = context.start.row.saturating_sub(line_count);
1529                            context.start.column = 0;
1530                        }
1531                        ExpandExcerptDirection::Down => {
1532                            context.end.row =
1533                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1534                            context.end.column = excerpt.buffer.line_len(context.end.row);
1535                        }
1536                        ExpandExcerptDirection::UpAndDown => {
1537                            context.start.row = context.start.row.saturating_sub(line_count);
1538                            context.start.column = 0;
1539                            context.end.row =
1540                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1541                            context.end.column = excerpt.buffer.line_len(context.end.row);
1542                        }
1543                    }
1544                }
1545
1546                Some(ExcerptRange {
1547                    context,
1548                    primary: excerpt.range.primary.to_point(&excerpt.buffer),
1549                })
1550            });
1551            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1552            for range in expanded_ranges {
1553                if let Some(last_range) = merged_ranges.last_mut()
1554                    && last_range.context.end >= range.context.start
1555                {
1556                    last_range.context.end = range.context.end;
1557                    continue;
1558                }
1559                merged_ranges.push(range)
1560            }
1561            let Some(excerpt_id) = excerpt_ids.first() else {
1562                continue;
1563            };
1564            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1565                continue;
1566            };
1567
1568            let Some(buffer) = self
1569                .buffers
1570                .borrow()
1571                .get(buffer_id)
1572                .map(|b| b.buffer.clone())
1573            else {
1574                continue;
1575            };
1576
1577            let buffer_snapshot = buffer.read(cx).snapshot();
1578            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1579        }
1580    }
1581
1582    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1583    pub fn set_excerpts_for_path(
1584        &mut self,
1585        path: PathKey,
1586        buffer: Entity<Buffer>,
1587        ranges: impl IntoIterator<Item = Range<Point>>,
1588        context_line_count: u32,
1589        cx: &mut Context<Self>,
1590    ) -> (Vec<Range<Anchor>>, bool) {
1591        let buffer_snapshot = buffer.read(cx).snapshot();
1592        let excerpt_ranges = build_excerpt_ranges(ranges, context_line_count, &buffer_snapshot);
1593
1594        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1595        self.set_merged_excerpt_ranges_for_path(
1596            path,
1597            buffer,
1598            excerpt_ranges,
1599            &buffer_snapshot,
1600            new,
1601            counts,
1602            cx,
1603        )
1604    }
1605
1606    pub fn set_excerpt_ranges_for_path(
1607        &mut self,
1608        path: PathKey,
1609        buffer: Entity<Buffer>,
1610        buffer_snapshot: &BufferSnapshot,
1611        excerpt_ranges: Vec<ExcerptRange<Point>>,
1612        cx: &mut Context<Self>,
1613    ) -> (Vec<Range<Anchor>>, bool) {
1614        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1615        self.set_merged_excerpt_ranges_for_path(
1616            path,
1617            buffer,
1618            excerpt_ranges,
1619            buffer_snapshot,
1620            new,
1621            counts,
1622            cx,
1623        )
1624    }
1625
1626    pub fn set_anchored_excerpts_for_path(
1627        &self,
1628        buffer: Entity<Buffer>,
1629        ranges: Vec<Range<text::Anchor>>,
1630        context_line_count: u32,
1631        cx: &mut Context<Self>,
1632    ) -> Task<Vec<Range<Anchor>>> {
1633        let buffer_snapshot = buffer.read(cx).snapshot();
1634        let path_key = PathKey::for_buffer(&buffer, cx);
1635        cx.spawn(async move |multi_buffer, cx| {
1636            let snapshot = buffer_snapshot.clone();
1637            let (excerpt_ranges, new, counts) = cx
1638                .background_spawn(async move {
1639                    let ranges = ranges.into_iter().map(|range| range.to_point(&snapshot));
1640                    let excerpt_ranges =
1641                        build_excerpt_ranges(ranges, context_line_count, &snapshot);
1642                    let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1643                    (excerpt_ranges, new, counts)
1644                })
1645                .await;
1646
1647            multi_buffer
1648                .update(cx, move |multi_buffer, cx| {
1649                    let (ranges, _) = multi_buffer.set_merged_excerpt_ranges_for_path(
1650                        path_key,
1651                        buffer,
1652                        excerpt_ranges,
1653                        &buffer_snapshot,
1654                        new,
1655                        counts,
1656                        cx,
1657                    );
1658                    ranges
1659                })
1660                .ok()
1661                .unwrap_or_default()
1662        })
1663    }
1664
1665    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1666    fn set_merged_excerpt_ranges_for_path(
1667        &mut self,
1668        path: PathKey,
1669        buffer: Entity<Buffer>,
1670        ranges: Vec<ExcerptRange<Point>>,
1671        buffer_snapshot: &BufferSnapshot,
1672        new: Vec<ExcerptRange<Point>>,
1673        counts: Vec<usize>,
1674        cx: &mut Context<Self>,
1675    ) -> (Vec<Range<Anchor>>, bool) {
1676        let (excerpt_ids, added_a_new_excerpt) =
1677            self.update_path_excerpts(path, buffer, buffer_snapshot, new, cx);
1678
1679        let mut result = Vec::new();
1680        let mut ranges = ranges.into_iter();
1681        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(counts.into_iter()) {
1682            for range in ranges.by_ref().take(range_count) {
1683                let range = Anchor::range_in_buffer(
1684                    excerpt_id,
1685                    buffer_snapshot.remote_id(),
1686                    buffer_snapshot.anchor_before(&range.primary.start)
1687                        ..buffer_snapshot.anchor_after(&range.primary.end),
1688                );
1689                result.push(range)
1690            }
1691        }
1692        (result, added_a_new_excerpt)
1693    }
1694
1695    fn merge_excerpt_ranges<'a>(
1696        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1697    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1698        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1699        let mut counts: Vec<usize> = Vec::new();
1700        for range in expanded_ranges {
1701            if let Some(last_range) = merged_ranges.last_mut() {
1702                debug_assert!(
1703                    last_range.context.start <= range.context.start,
1704                    "Last range: {last_range:?} Range: {range:?}"
1705                );
1706                if last_range.context.end >= range.context.start
1707                    || last_range.context.end.row + 1 == range.context.start.row
1708                {
1709                    last_range.context.end = range.context.end.max(last_range.context.end);
1710                    *counts.last_mut().unwrap() += 1;
1711                    continue;
1712                }
1713            }
1714            merged_ranges.push(range.clone());
1715            counts.push(1);
1716        }
1717        (merged_ranges, counts)
1718    }
1719
1720    fn update_path_excerpts(
1721        &mut self,
1722        path: PathKey,
1723        buffer: Entity<Buffer>,
1724        buffer_snapshot: &BufferSnapshot,
1725        new: Vec<ExcerptRange<Point>>,
1726        cx: &mut Context<Self>,
1727    ) -> (Vec<ExcerptId>, bool) {
1728        let mut insert_after = self
1729            .excerpts_by_path
1730            .range(..path.clone())
1731            .next_back()
1732            .map(|(_, value)| *value.last().unwrap())
1733            .unwrap_or(ExcerptId::min());
1734
1735        let existing = self
1736            .excerpts_by_path
1737            .get(&path)
1738            .cloned()
1739            .unwrap_or_default();
1740
1741        let mut new_iter = new.into_iter().peekable();
1742        let mut existing_iter = existing.into_iter().peekable();
1743
1744        let mut excerpt_ids = Vec::new();
1745        let mut to_remove = Vec::new();
1746        let mut to_insert: Vec<(ExcerptId, ExcerptRange<Point>)> = Vec::new();
1747        let mut added_a_new_excerpt = false;
1748        let snapshot = self.snapshot(cx);
1749
1750        let mut next_excerpt_id =
1751            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1752                last_entry.id.0 + 1
1753            } else {
1754                1
1755            };
1756
1757        let mut next_excerpt_id = move || ExcerptId(post_inc(&mut next_excerpt_id));
1758
1759        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1760        excerpts_cursor.next();
1761
1762        loop {
1763            let new = new_iter.peek();
1764            let existing = if let Some(existing_id) = existing_iter.peek() {
1765                let locator = snapshot.excerpt_locator_for_id(*existing_id);
1766                excerpts_cursor.seek_forward(&Some(locator), Bias::Left);
1767                if let Some(excerpt) = excerpts_cursor.item() {
1768                    if excerpt.buffer_id != buffer_snapshot.remote_id() {
1769                        to_remove.push(*existing_id);
1770                        existing_iter.next();
1771                        continue;
1772                    }
1773                    Some((
1774                        *existing_id,
1775                        excerpt.range.context.to_point(buffer_snapshot),
1776                    ))
1777                } else {
1778                    None
1779                }
1780            } else {
1781                None
1782            };
1783
1784            if let Some((last_id, last)) = to_insert.last_mut() {
1785                if let Some(new) = new
1786                    && last.context.end >= new.context.start
1787                {
1788                    last.context.end = last.context.end.max(new.context.end);
1789                    excerpt_ids.push(*last_id);
1790                    new_iter.next();
1791                    continue;
1792                }
1793                if let Some((existing_id, existing_range)) = &existing
1794                    && last.context.end >= existing_range.start
1795                {
1796                    last.context.end = last.context.end.max(existing_range.end);
1797                    to_remove.push(*existing_id);
1798                    self.snapshot
1799                        .borrow_mut()
1800                        .replaced_excerpts
1801                        .insert(*existing_id, *last_id);
1802                    existing_iter.next();
1803                    continue;
1804                }
1805            }
1806
1807            match (new, existing) {
1808                (None, None) => break,
1809                (None, Some((existing_id, _))) => {
1810                    existing_iter.next();
1811                    to_remove.push(existing_id);
1812                    continue;
1813                }
1814                (Some(_), None) => {
1815                    added_a_new_excerpt = true;
1816                    let new_id = next_excerpt_id();
1817                    excerpt_ids.push(new_id);
1818                    to_insert.push((new_id, new_iter.next().unwrap()));
1819                    continue;
1820                }
1821                (Some(new), Some((_, existing_range))) => {
1822                    if existing_range.end < new.context.start {
1823                        let existing_id = existing_iter.next().unwrap();
1824                        to_remove.push(existing_id);
1825                        continue;
1826                    } else if existing_range.start > new.context.end {
1827                        let new_id = next_excerpt_id();
1828                        excerpt_ids.push(new_id);
1829                        to_insert.push((new_id, new_iter.next().unwrap()));
1830                        continue;
1831                    }
1832
1833                    if existing_range.start == new.context.start
1834                        && existing_range.end == new.context.end
1835                    {
1836                        self.insert_excerpts_with_ids_after(
1837                            insert_after,
1838                            buffer.clone(),
1839                            mem::take(&mut to_insert),
1840                            cx,
1841                        );
1842                        insert_after = existing_iter.next().unwrap();
1843                        excerpt_ids.push(insert_after);
1844                        new_iter.next();
1845                    } else {
1846                        let existing_id = existing_iter.next().unwrap();
1847                        let new_id = next_excerpt_id();
1848                        self.snapshot
1849                            .borrow_mut()
1850                            .replaced_excerpts
1851                            .insert(existing_id, new_id);
1852                        to_remove.push(existing_id);
1853                        let mut range = new_iter.next().unwrap();
1854                        range.context.start = range.context.start.min(existing_range.start);
1855                        range.context.end = range.context.end.max(existing_range.end);
1856                        excerpt_ids.push(new_id);
1857                        to_insert.push((new_id, range));
1858                    }
1859                }
1860            };
1861        }
1862
1863        self.insert_excerpts_with_ids_after(insert_after, buffer, to_insert, cx);
1864        self.remove_excerpts(to_remove, cx);
1865        if excerpt_ids.is_empty() {
1866            self.excerpts_by_path.remove(&path);
1867        } else {
1868            for excerpt_id in &excerpt_ids {
1869                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1870            }
1871            self.excerpts_by_path
1872                .insert(path, excerpt_ids.iter().dedup().cloned().collect());
1873        }
1874
1875        (excerpt_ids, added_a_new_excerpt)
1876    }
1877
1878    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1879        self.excerpts_by_path.keys().cloned()
1880    }
1881
1882    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1883        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1884            self.remove_excerpts(to_remove, cx)
1885        }
1886    }
1887
1888    pub fn insert_excerpts_after<O>(
1889        &mut self,
1890        prev_excerpt_id: ExcerptId,
1891        buffer: Entity<Buffer>,
1892        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1893        cx: &mut Context<Self>,
1894    ) -> Vec<ExcerptId>
1895    where
1896        O: text::ToOffset,
1897    {
1898        let mut ids = Vec::new();
1899        let mut next_excerpt_id =
1900            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1901                last_entry.id.0 + 1
1902            } else {
1903                1
1904            };
1905        self.insert_excerpts_with_ids_after(
1906            prev_excerpt_id,
1907            buffer,
1908            ranges.into_iter().map(|range| {
1909                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1910                ids.push(id);
1911                (id, range)
1912            }),
1913            cx,
1914        );
1915        ids
1916    }
1917
1918    pub fn insert_excerpts_with_ids_after<O>(
1919        &mut self,
1920        prev_excerpt_id: ExcerptId,
1921        buffer: Entity<Buffer>,
1922        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1923        cx: &mut Context<Self>,
1924    ) where
1925        O: text::ToOffset,
1926    {
1927        assert_eq!(self.history.transaction_depth, 0);
1928        let mut ranges = ranges.into_iter().peekable();
1929        if ranges.peek().is_none() {
1930            return Default::default();
1931        }
1932
1933        self.sync(cx);
1934
1935        let buffer_snapshot = buffer.read(cx).snapshot();
1936        let buffer_id = buffer_snapshot.remote_id();
1937
1938        let mut buffers = self.buffers.borrow_mut();
1939        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1940            self.buffer_changed_since_sync.replace(true);
1941            buffer.update(cx, |buffer, _| {
1942                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1943            });
1944            BufferState {
1945                last_version: buffer_snapshot.version().clone(),
1946                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1947                excerpts: Default::default(),
1948                _subscriptions: [
1949                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1950                    cx.subscribe(&buffer, Self::on_buffer_event),
1951                ],
1952                buffer: buffer.clone(),
1953            }
1954        });
1955
1956        let mut snapshot = self.snapshot.borrow_mut();
1957
1958        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1959        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1960        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1961        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1962        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1963
1964        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1965        new_excerpts.update_last(
1966            |excerpt| {
1967                excerpt.has_trailing_newline = true;
1968            },
1969            &(),
1970        );
1971
1972        let next_locator = if let Some(excerpt) = cursor.item() {
1973            excerpt.locator.clone()
1974        } else {
1975            Locator::max()
1976        };
1977
1978        let mut excerpts = Vec::new();
1979        while let Some((id, range)) = ranges.next() {
1980            let locator = Locator::between(&prev_locator, &next_locator);
1981            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1982                buffer_state.excerpts.insert(ix, locator.clone());
1983            }
1984            let range = ExcerptRange {
1985                context: buffer_snapshot.anchor_before(&range.context.start)
1986                    ..buffer_snapshot.anchor_after(&range.context.end),
1987                primary: buffer_snapshot.anchor_before(&range.primary.start)
1988                    ..buffer_snapshot.anchor_after(&range.primary.end),
1989            };
1990            excerpts.push((id, range.clone()));
1991            let excerpt = Excerpt::new(
1992                id,
1993                locator.clone(),
1994                buffer_id,
1995                buffer_snapshot.clone(),
1996                range,
1997                ranges.peek().is_some() || cursor.item().is_some(),
1998            );
1999            new_excerpts.push(excerpt, &());
2000            prev_locator = locator.clone();
2001
2002            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
2003                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
2004            }
2005            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
2006        }
2007
2008        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
2009
2010        let suffix = cursor.suffix();
2011        let changed_trailing_excerpt = suffix.is_empty();
2012        new_excerpts.append(suffix, &());
2013        drop(cursor);
2014        snapshot.excerpts = new_excerpts;
2015        snapshot.excerpt_ids = new_excerpt_ids;
2016        if changed_trailing_excerpt {
2017            snapshot.trailing_excerpt_update_count += 1;
2018        }
2019
2020        self.sync_diff_transforms(
2021            &mut snapshot,
2022            vec![Edit {
2023                old: edit_start..edit_start,
2024                new: edit_start..edit_end,
2025            }],
2026            DiffChangeKind::BufferEdited,
2027        );
2028        cx.emit(Event::Edited {
2029            singleton_buffer_edited: false,
2030            edited_buffer: None,
2031        });
2032        cx.emit(Event::ExcerptsAdded {
2033            buffer,
2034            predecessor: prev_excerpt_id,
2035            excerpts,
2036        });
2037        cx.notify();
2038    }
2039
2040    pub fn clear(&mut self, cx: &mut Context<Self>) {
2041        self.sync(cx);
2042        let ids = self.excerpt_ids();
2043        let removed_buffer_ids = self
2044            .buffers
2045            .borrow_mut()
2046            .drain()
2047            .map(|(id, _)| id)
2048            .collect();
2049        self.excerpts_by_path.clear();
2050        self.paths_by_excerpt.clear();
2051        let mut snapshot = self.snapshot.borrow_mut();
2052        let start = ExcerptOffset::new(0);
2053        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2054        snapshot.excerpts = Default::default();
2055        snapshot.trailing_excerpt_update_count += 1;
2056        snapshot.is_dirty = false;
2057        snapshot.has_deleted_file = false;
2058        snapshot.has_conflict = false;
2059        snapshot.replaced_excerpts.clear();
2060
2061        self.sync_diff_transforms(
2062            &mut snapshot,
2063            vec![Edit {
2064                old: start..prev_len,
2065                new: start..start,
2066            }],
2067            DiffChangeKind::BufferEdited,
2068        );
2069        cx.emit(Event::Edited {
2070            singleton_buffer_edited: false,
2071            edited_buffer: None,
2072        });
2073        cx.emit(Event::ExcerptsRemoved {
2074            ids,
2075            removed_buffer_ids,
2076        });
2077        cx.notify();
2078    }
2079
2080    pub fn excerpts_for_buffer(
2081        &self,
2082        buffer_id: BufferId,
2083        cx: &App,
2084    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2085        let mut excerpts = Vec::new();
2086        let snapshot = self.read(cx);
2087        let buffers = self.buffers.borrow();
2088        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2089        if let Some(locators) = buffers.get(&buffer_id).map(|state| &state.excerpts) {
2090            for locator in locators {
2091                cursor.seek_forward(&Some(locator), Bias::Left);
2092                if let Some(excerpt) = cursor.item()
2093                    && excerpt.locator == *locator
2094                {
2095                    excerpts.push((excerpt.id, excerpt.range.clone()));
2096                }
2097            }
2098        }
2099
2100        excerpts
2101    }
2102
2103    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2104        let snapshot = self.read(cx);
2105        let buffers = self.buffers.borrow();
2106        let mut excerpts = snapshot
2107            .excerpts
2108            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(&());
2109        let mut diff_transforms = snapshot
2110            .diff_transforms
2111            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(&());
2112        diff_transforms.next();
2113        let locators = buffers
2114            .get(&buffer_id)
2115            .into_iter()
2116            .flat_map(|state| &state.excerpts);
2117        let mut result = Vec::new();
2118        for locator in locators {
2119            excerpts.seek_forward(&Some(locator), Bias::Left);
2120            if let Some(excerpt) = excerpts.item()
2121                && excerpt.locator == *locator
2122            {
2123                let excerpt_start = excerpts.start().1.clone();
2124                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2125
2126                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2127                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2128                let start = diff_transforms.start().1.0 + overshoot;
2129
2130                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2131                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2132                let end = diff_transforms.start().1.0 + overshoot;
2133
2134                result.push(start..end)
2135            }
2136        }
2137        result
2138    }
2139
2140    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2141        self.snapshot
2142            .borrow()
2143            .excerpts
2144            .iter()
2145            .map(|entry| entry.buffer_id)
2146            .collect()
2147    }
2148
2149    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2150        self.snapshot
2151            .borrow()
2152            .excerpts
2153            .iter()
2154            .map(|entry| entry.id)
2155            .collect()
2156    }
2157
2158    pub fn excerpt_containing(
2159        &self,
2160        position: impl ToOffset,
2161        cx: &App,
2162    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2163        let snapshot = self.read(cx);
2164        let offset = position.to_offset(&snapshot);
2165
2166        let mut cursor = snapshot.cursor::<usize>();
2167        cursor.seek(&offset);
2168        cursor
2169            .excerpt()
2170            .or_else(|| snapshot.excerpts.last())
2171            .map(|excerpt| {
2172                (
2173                    excerpt.id,
2174                    self.buffers
2175                        .borrow()
2176                        .get(&excerpt.buffer_id)
2177                        .unwrap()
2178                        .buffer
2179                        .clone(),
2180                    excerpt.range.context.clone(),
2181                )
2182            })
2183    }
2184
2185    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2186        if let Some(buffer_id) = anchor.buffer_id {
2187            self.buffer(buffer_id)
2188        } else {
2189            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2190            Some(buffer)
2191        }
2192    }
2193
2194    // If point is at the end of the buffer, the last excerpt is returned
2195    pub fn point_to_buffer_offset<T: ToOffset>(
2196        &self,
2197        point: T,
2198        cx: &App,
2199    ) -> Option<(Entity<Buffer>, usize)> {
2200        let snapshot = self.read(cx);
2201        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2202        Some((
2203            self.buffers
2204                .borrow()
2205                .get(&buffer.remote_id())?
2206                .buffer
2207                .clone(),
2208            offset,
2209        ))
2210    }
2211
2212    // If point is at the end of the buffer, the last excerpt is returned
2213    pub fn point_to_buffer_point<T: ToPoint>(
2214        &self,
2215        point: T,
2216        cx: &App,
2217    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2218        let snapshot = self.read(cx);
2219        let (buffer, point, is_main_buffer) =
2220            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2221        Some((
2222            self.buffers
2223                .borrow()
2224                .get(&buffer.remote_id())?
2225                .buffer
2226                .clone(),
2227            point,
2228            is_main_buffer,
2229        ))
2230    }
2231
2232    pub fn buffer_point_to_anchor(
2233        &self,
2234        buffer: &Entity<Buffer>,
2235        point: Point,
2236        cx: &App,
2237    ) -> Option<Anchor> {
2238        let mut found = None;
2239        let snapshot = buffer.read(cx).snapshot();
2240        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2241            let start = range.context.start.to_point(&snapshot);
2242            let end = range.context.end.to_point(&snapshot);
2243            if start <= point && point < end {
2244                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2245                break;
2246            }
2247            if point < start {
2248                found = Some((start, excerpt_id));
2249            }
2250            if point > end {
2251                found = Some((end, excerpt_id));
2252            }
2253        }
2254
2255        found.map(|(point, excerpt_id)| {
2256            let text_anchor = snapshot.anchor_after(point);
2257            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2258        })
2259    }
2260
2261    pub fn remove_excerpts(
2262        &mut self,
2263        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2264        cx: &mut Context<Self>,
2265    ) {
2266        self.sync(cx);
2267        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2268        if ids.is_empty() {
2269            return;
2270        }
2271
2272        let mut buffers = self.buffers.borrow_mut();
2273        let mut snapshot = self.snapshot.borrow_mut();
2274        let mut new_excerpts = SumTree::default();
2275        let mut cursor = snapshot
2276            .excerpts
2277            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2278        let mut edits = Vec::new();
2279        let mut excerpt_ids = ids.iter().copied().peekable();
2280        let mut removed_buffer_ids = Vec::new();
2281
2282        while let Some(excerpt_id) = excerpt_ids.next() {
2283            self.paths_by_excerpt.remove(&excerpt_id);
2284            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2285            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2286            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), &());
2287
2288            if let Some(mut excerpt) = cursor.item() {
2289                if excerpt.id != excerpt_id {
2290                    continue;
2291                }
2292                let mut old_start = cursor.start().1;
2293
2294                // Skip over the removed excerpt.
2295                'remove_excerpts: loop {
2296                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2297                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2298                        if buffer_state.excerpts.is_empty() {
2299                            log::debug!(
2300                                "removing buffer and diff for buffer {}",
2301                                excerpt.buffer_id
2302                            );
2303                            buffers.remove(&excerpt.buffer_id);
2304                            removed_buffer_ids.push(excerpt.buffer_id);
2305                        }
2306                    }
2307                    cursor.next();
2308
2309                    // Skip over any subsequent excerpts that are also removed.
2310                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2311                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2312                        if let Some(next_excerpt) = cursor.item()
2313                            && next_excerpt.locator == *next_locator
2314                        {
2315                            excerpt_ids.next();
2316                            excerpt = next_excerpt;
2317                            continue 'remove_excerpts;
2318                        }
2319                    }
2320
2321                    break;
2322                }
2323
2324                // When removing the last excerpt, remove the trailing newline from
2325                // the previous excerpt.
2326                if cursor.item().is_none() && old_start.value > 0 {
2327                    old_start.value -= 1;
2328                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2329                }
2330
2331                // Push an edit for the removal of this run of excerpts.
2332                let old_end = cursor.start().1;
2333                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2334                edits.push(Edit {
2335                    old: old_start..old_end,
2336                    new: new_start..new_start,
2337                });
2338            }
2339        }
2340        let suffix = cursor.suffix();
2341        let changed_trailing_excerpt = suffix.is_empty();
2342        new_excerpts.append(suffix, &());
2343        drop(cursor);
2344        snapshot.excerpts = new_excerpts;
2345        for buffer_id in &removed_buffer_ids {
2346            self.diffs.remove(buffer_id);
2347            snapshot.diffs.remove(buffer_id);
2348        }
2349
2350        if changed_trailing_excerpt {
2351            snapshot.trailing_excerpt_update_count += 1;
2352        }
2353
2354        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2355        self.buffer_changed_since_sync.replace(true);
2356        cx.emit(Event::Edited {
2357            singleton_buffer_edited: false,
2358            edited_buffer: None,
2359        });
2360        cx.emit(Event::ExcerptsRemoved {
2361            ids,
2362            removed_buffer_ids,
2363        });
2364        cx.notify();
2365    }
2366
2367    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2368        &self,
2369        anchors: Anchors,
2370        cx: &mut Context<Self>,
2371    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2372        let borrow = self.buffers.borrow();
2373        let mut error = None;
2374        let mut futures = Vec::new();
2375        for anchor in anchors {
2376            if let Some(buffer_id) = anchor.buffer_id {
2377                if let Some(buffer) = borrow.get(&buffer_id) {
2378                    buffer.buffer.update(cx, |buffer, _| {
2379                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2380                    });
2381                } else {
2382                    error = Some(anyhow!(
2383                        "buffer {buffer_id} is not part of this multi-buffer"
2384                    ));
2385                    break;
2386                }
2387            }
2388        }
2389        async move {
2390            if let Some(error) = error {
2391                Err(error)?;
2392            }
2393            for future in futures {
2394                future.await?;
2395            }
2396            Ok(())
2397        }
2398    }
2399
2400    pub fn text_anchor_for_position<T: ToOffset>(
2401        &self,
2402        position: T,
2403        cx: &App,
2404    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2405        let snapshot = self.read(cx);
2406        let anchor = snapshot.anchor_before(position);
2407        let buffer = self
2408            .buffers
2409            .borrow()
2410            .get(&anchor.buffer_id?)?
2411            .buffer
2412            .clone();
2413        Some((buffer, anchor.text_anchor))
2414    }
2415
2416    fn on_buffer_event(
2417        &mut self,
2418        buffer: Entity<Buffer>,
2419        event: &language::BufferEvent,
2420        cx: &mut Context<Self>,
2421    ) {
2422        use language::BufferEvent;
2423        cx.emit(match event {
2424            BufferEvent::Edited => Event::Edited {
2425                singleton_buffer_edited: true,
2426                edited_buffer: Some(buffer),
2427            },
2428            BufferEvent::DirtyChanged => Event::DirtyChanged,
2429            BufferEvent::Saved => Event::Saved,
2430            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2431            BufferEvent::Reloaded => Event::Reloaded,
2432            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2433            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2434            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2435            BufferEvent::CapabilityChanged => {
2436                self.capability = buffer.read(cx).capability();
2437                return;
2438            }
2439            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2440        });
2441    }
2442
2443    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2444        self.sync(cx);
2445        let mut snapshot = self.snapshot.borrow_mut();
2446        let diff = diff.read(cx);
2447        let buffer_id = diff.buffer_id;
2448        let diff = diff.snapshot(cx);
2449        snapshot.diffs.insert(buffer_id, diff);
2450    }
2451
2452    fn buffer_diff_changed(
2453        &mut self,
2454        diff: Entity<BufferDiff>,
2455        range: Range<text::Anchor>,
2456        cx: &mut Context<Self>,
2457    ) {
2458        self.sync(cx);
2459        self.buffer_changed_since_sync.replace(true);
2460
2461        let diff = diff.read(cx);
2462        let buffer_id = diff.buffer_id;
2463        let buffers = self.buffers.borrow();
2464        let Some(buffer_state) = buffers.get(&buffer_id) else {
2465            return;
2466        };
2467
2468        let buffer = buffer_state.buffer.read(cx);
2469        let diff_change_range = range.to_offset(buffer);
2470
2471        let new_diff = diff.snapshot(cx);
2472        let mut snapshot = self.snapshot.borrow_mut();
2473        let base_text_changed = snapshot
2474            .diffs
2475            .get(&buffer_id)
2476            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2477
2478        snapshot.diffs.insert(buffer_id, new_diff);
2479
2480        let mut excerpt_edits = Vec::new();
2481        for locator in &buffer_state.excerpts {
2482            let mut cursor = snapshot
2483                .excerpts
2484                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2485            cursor.seek_forward(&Some(locator), Bias::Left);
2486            if let Some(excerpt) = cursor.item()
2487                && excerpt.locator == *locator
2488            {
2489                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2490                if diff_change_range.end < excerpt_buffer_range.start
2491                    || diff_change_range.start > excerpt_buffer_range.end
2492                {
2493                    continue;
2494                }
2495                let excerpt_start = cursor.start().1;
2496                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2497                let diff_change_start_in_excerpt = ExcerptOffset::new(
2498                    diff_change_range
2499                        .start
2500                        .saturating_sub(excerpt_buffer_range.start),
2501                );
2502                let diff_change_end_in_excerpt = ExcerptOffset::new(
2503                    diff_change_range
2504                        .end
2505                        .saturating_sub(excerpt_buffer_range.start),
2506                );
2507                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2508                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2509                excerpt_edits.push(Edit {
2510                    old: edit_start..edit_end,
2511                    new: edit_start..edit_end,
2512                });
2513            }
2514        }
2515
2516        self.sync_diff_transforms(
2517            &mut snapshot,
2518            excerpt_edits,
2519            DiffChangeKind::DiffUpdated {
2520                base_changed: base_text_changed,
2521            },
2522        );
2523        cx.emit(Event::Edited {
2524            singleton_buffer_edited: false,
2525            edited_buffer: None,
2526        });
2527    }
2528
2529    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2530        self.buffers
2531            .borrow()
2532            .values()
2533            .map(|state| state.buffer.clone())
2534            .collect()
2535    }
2536
2537    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2538        self.buffers.borrow().keys().copied().collect()
2539    }
2540
2541    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2542        self.buffers
2543            .borrow()
2544            .get(&buffer_id)
2545            .map(|state| state.buffer.clone())
2546    }
2547
2548    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2549        self.point_to_buffer_offset(point, cx)
2550            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2551    }
2552
2553    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2554        let buffer_id = self
2555            .snapshot
2556            .borrow()
2557            .excerpts
2558            .first()
2559            .map(|excerpt| excerpt.buffer.remote_id());
2560        buffer_id
2561            .and_then(|buffer_id| self.buffer(buffer_id))
2562            .map(|buffer| {
2563                let buffer = buffer.read(cx);
2564                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2565            })
2566            .unwrap_or_else(move || self.language_settings_at(0, cx))
2567    }
2568
2569    pub fn language_settings_at<'a, T: ToOffset>(
2570        &'a self,
2571        point: T,
2572        cx: &'a App,
2573    ) -> Cow<'a, LanguageSettings> {
2574        let mut language = None;
2575        let mut file = None;
2576        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2577            let buffer = buffer.read(cx);
2578            language = buffer.language_at(offset);
2579            file = buffer.file();
2580        }
2581        language_settings(language.map(|l| l.name()), file, cx)
2582    }
2583
2584    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2585        self.buffers
2586            .borrow()
2587            .values()
2588            .for_each(|state| f(&state.buffer))
2589    }
2590
2591    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2592        if let Some(title) = self.title.as_ref() {
2593            return title.into();
2594        }
2595
2596        if let Some(buffer) = self.as_singleton() {
2597            let buffer = buffer.read(cx);
2598
2599            if let Some(file) = buffer.file() {
2600                return file.file_name(cx).to_string_lossy();
2601            }
2602
2603            if let Some(title) = self.buffer_content_title(buffer) {
2604                return title;
2605            }
2606        };
2607
2608        "untitled".into()
2609    }
2610
2611    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2612        let mut is_leading_whitespace = true;
2613        let mut count = 0;
2614        let mut prev_was_space = false;
2615        let mut title = String::new();
2616
2617        for ch in buffer.snapshot().chars() {
2618            if is_leading_whitespace && ch.is_whitespace() {
2619                continue;
2620            }
2621
2622            is_leading_whitespace = false;
2623
2624            if ch == '\n' || count >= 40 {
2625                break;
2626            }
2627
2628            if ch.is_whitespace() {
2629                if !prev_was_space {
2630                    title.push(' ');
2631                    count += 1;
2632                    prev_was_space = true;
2633                }
2634            } else {
2635                title.push(ch);
2636                count += 1;
2637                prev_was_space = false;
2638            }
2639        }
2640
2641        let title = title.trim_end().to_string();
2642
2643        if title.is_empty() {
2644            return None;
2645        }
2646
2647        Some(title.into())
2648    }
2649
2650    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2651        self.title = Some(title);
2652        cx.notify();
2653    }
2654
2655    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2656    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2657        for buffer_state in self.buffers.borrow().values() {
2658            buffer_state
2659                .buffer
2660                .update(cx, |buffer, _cx| buffer.refresh_preview());
2661        }
2662    }
2663
2664    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2665    pub fn preserve_preview(&self, cx: &App) -> bool {
2666        self.buffers
2667            .borrow()
2668            .values()
2669            .all(|state| state.buffer.read(cx).preserve_preview())
2670    }
2671
2672    #[cfg(any(test, feature = "test-support"))]
2673    pub fn is_parsing(&self, cx: &App) -> bool {
2674        self.as_singleton().unwrap().read(cx).is_parsing()
2675    }
2676
2677    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2678        let buffer_id = diff.read(cx).buffer_id;
2679        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2680        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2681    }
2682
2683    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2684        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2685    }
2686
2687    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2688        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2689    }
2690
2691    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2692        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2693    }
2694
2695    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2696        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2697        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2698    }
2699
2700    pub fn all_diff_hunks_expanded(&self) -> bool {
2701        self.snapshot.borrow().all_diff_hunks_expanded
2702    }
2703
2704    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2705        self.snapshot.borrow_mut().all_diff_hunks_expanded = false;
2706        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2707    }
2708
2709    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2710        self.read(cx)
2711            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2712            .nth(1)
2713            .is_some()
2714    }
2715
2716    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2717        let snapshot = self.read(cx);
2718        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2719        let offset_range = range.to_offset(&snapshot);
2720        cursor.seek(&offset_range.start, Bias::Left);
2721        while let Some(item) = cursor.item() {
2722            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2723                break;
2724            }
2725            if item.hunk_info().is_some() {
2726                return true;
2727            }
2728            cursor.next();
2729        }
2730        false
2731    }
2732
2733    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2734        let snapshot = self.read(cx);
2735        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2736        for range in ranges {
2737            let range = range.to_point(&snapshot);
2738            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2739            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2740            let start = start.saturating_sub(1);
2741            let end = snapshot.len().min(end + 1);
2742            cursor.seek(&start, Bias::Right);
2743            while let Some(item) = cursor.item() {
2744                if *cursor.start() >= end {
2745                    break;
2746                }
2747                if item.hunk_info().is_some() {
2748                    return true;
2749                }
2750                cursor.next();
2751            }
2752        }
2753        false
2754    }
2755
2756    pub fn expand_or_collapse_diff_hunks_inner(
2757        &mut self,
2758        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2759        expand: bool,
2760        cx: &mut Context<Self>,
2761    ) {
2762        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2763            return;
2764        }
2765        self.sync(cx);
2766        let mut snapshot = self.snapshot.borrow_mut();
2767        let mut excerpt_edits = Vec::new();
2768        let mut last_hunk_row = None;
2769        for (range, end_excerpt_id) in ranges {
2770            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2771                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2772                    continue;
2773                }
2774                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2775                    continue;
2776                }
2777                let start = Anchor::in_buffer(
2778                    diff_hunk.excerpt_id,
2779                    diff_hunk.buffer_id,
2780                    diff_hunk.buffer_range.start,
2781                );
2782                let end = Anchor::in_buffer(
2783                    diff_hunk.excerpt_id,
2784                    diff_hunk.buffer_id,
2785                    diff_hunk.buffer_range.end,
2786                );
2787                let start = snapshot.excerpt_offset_for_anchor(&start);
2788                let end = snapshot.excerpt_offset_for_anchor(&end);
2789                last_hunk_row = Some(diff_hunk.row_range.start);
2790                excerpt_edits.push(text::Edit {
2791                    old: start..end,
2792                    new: start..end,
2793                });
2794            }
2795        }
2796
2797        self.sync_diff_transforms(
2798            &mut snapshot,
2799            excerpt_edits,
2800            DiffChangeKind::ExpandOrCollapseHunks { expand },
2801        );
2802        cx.emit(Event::DiffHunksToggled);
2803        cx.emit(Event::Edited {
2804            singleton_buffer_edited: false,
2805            edited_buffer: None,
2806        });
2807    }
2808
2809    pub fn expand_or_collapse_diff_hunks(
2810        &mut self,
2811        ranges: Vec<Range<Anchor>>,
2812        expand: bool,
2813        cx: &mut Context<Self>,
2814    ) {
2815        let snapshot = self.snapshot.borrow().clone();
2816        let ranges = ranges.iter().map(move |range| {
2817            let end_excerpt_id = range.end.excerpt_id;
2818            let range = range.to_point(&snapshot);
2819            let mut peek_end = range.end;
2820            if range.end.row < snapshot.max_row().0 {
2821                peek_end = Point::new(range.end.row + 1, 0);
2822            };
2823            (range.start..peek_end, end_excerpt_id)
2824        });
2825        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2826    }
2827
2828    pub fn resize_excerpt(
2829        &mut self,
2830        id: ExcerptId,
2831        range: Range<text::Anchor>,
2832        cx: &mut Context<Self>,
2833    ) {
2834        self.sync(cx);
2835
2836        let mut snapshot = self.snapshot.borrow_mut();
2837        let locator = snapshot.excerpt_locator_for_id(id);
2838        let mut new_excerpts = SumTree::default();
2839        let mut cursor = snapshot
2840            .excerpts
2841            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2842        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2843
2844        let prefix = cursor.slice(&Some(locator), Bias::Left);
2845        new_excerpts.append(prefix, &());
2846
2847        let mut excerpt = cursor.item().unwrap().clone();
2848        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2849
2850        excerpt.range.context.start = range.start;
2851        excerpt.range.context.end = range.end;
2852        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2853
2854        excerpt.text_summary = excerpt
2855            .buffer
2856            .text_summary_for_range(excerpt.range.context.clone());
2857
2858        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2859        let old_start_offset = cursor.start().1;
2860        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2861        let edit = Edit {
2862            old: old_start_offset..old_start_offset + old_text_len,
2863            new: new_start_offset..new_start_offset + new_text_len,
2864        };
2865
2866        if let Some(last_edit) = edits.last_mut() {
2867            if last_edit.old.end == edit.old.start {
2868                last_edit.old.end = edit.old.end;
2869                last_edit.new.end = edit.new.end;
2870            } else {
2871                edits.push(edit);
2872            }
2873        } else {
2874            edits.push(edit);
2875        }
2876
2877        new_excerpts.push(excerpt, &());
2878
2879        cursor.next();
2880
2881        new_excerpts.append(cursor.suffix(), &());
2882
2883        drop(cursor);
2884        snapshot.excerpts = new_excerpts;
2885
2886        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2887        cx.emit(Event::Edited {
2888            singleton_buffer_edited: false,
2889            edited_buffer: None,
2890        });
2891        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2892        cx.notify();
2893    }
2894
2895    pub fn expand_excerpts(
2896        &mut self,
2897        ids: impl IntoIterator<Item = ExcerptId>,
2898        line_count: u32,
2899        direction: ExpandExcerptDirection,
2900        cx: &mut Context<Self>,
2901    ) {
2902        if line_count == 0 {
2903            return;
2904        }
2905        self.sync(cx);
2906        if !self.excerpts_by_path.is_empty() {
2907            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2908            return;
2909        }
2910        let mut snapshot = self.snapshot.borrow_mut();
2911
2912        let ids = ids.into_iter().collect::<Vec<_>>();
2913        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2914        let mut new_excerpts = SumTree::default();
2915        let mut cursor = snapshot
2916            .excerpts
2917            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2918        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2919
2920        for locator in &locators {
2921            let prefix = cursor.slice(&Some(locator), Bias::Left);
2922            new_excerpts.append(prefix, &());
2923
2924            let mut excerpt = cursor.item().unwrap().clone();
2925            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2926
2927            let up_line_count = if direction.should_expand_up() {
2928                line_count
2929            } else {
2930                0
2931            };
2932
2933            let start_row = excerpt
2934                .range
2935                .context
2936                .start
2937                .to_point(&excerpt.buffer)
2938                .row
2939                .saturating_sub(up_line_count);
2940            let start_point = Point::new(start_row, 0);
2941            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2942
2943            let down_line_count = if direction.should_expand_down() {
2944                line_count
2945            } else {
2946                0
2947            };
2948
2949            let mut end_point = excerpt.buffer.clip_point(
2950                excerpt.range.context.end.to_point(&excerpt.buffer)
2951                    + Point::new(down_line_count, 0),
2952                Bias::Left,
2953            );
2954            end_point.column = excerpt.buffer.line_len(end_point.row);
2955            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2956            excerpt.max_buffer_row = end_point.row;
2957
2958            excerpt.text_summary = excerpt
2959                .buffer
2960                .text_summary_for_range(excerpt.range.context.clone());
2961
2962            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2963            let old_start_offset = cursor.start().1;
2964            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2965            let edit = Edit {
2966                old: old_start_offset..old_start_offset + old_text_len,
2967                new: new_start_offset..new_start_offset + new_text_len,
2968            };
2969
2970            if let Some(last_edit) = edits.last_mut() {
2971                if last_edit.old.end == edit.old.start {
2972                    last_edit.old.end = edit.old.end;
2973                    last_edit.new.end = edit.new.end;
2974                } else {
2975                    edits.push(edit);
2976                }
2977            } else {
2978                edits.push(edit);
2979            }
2980
2981            new_excerpts.push(excerpt, &());
2982
2983            cursor.next();
2984        }
2985
2986        new_excerpts.append(cursor.suffix(), &());
2987
2988        drop(cursor);
2989        snapshot.excerpts = new_excerpts;
2990
2991        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2992        cx.emit(Event::Edited {
2993            singleton_buffer_edited: false,
2994            edited_buffer: None,
2995        });
2996        cx.emit(Event::ExcerptsExpanded { ids });
2997        cx.notify();
2998    }
2999
3000    fn sync(&self, cx: &App) {
3001        let changed = self.buffer_changed_since_sync.replace(false);
3002        if !changed {
3003            return;
3004        }
3005
3006        let mut snapshot = self.snapshot.borrow_mut();
3007        let mut excerpts_to_edit = Vec::new();
3008        let mut non_text_state_updated = false;
3009        let mut is_dirty = false;
3010        let mut has_deleted_file = false;
3011        let mut has_conflict = false;
3012        let mut edited = false;
3013        let mut buffers = self.buffers.borrow_mut();
3014        for buffer_state in buffers.values_mut() {
3015            let buffer = buffer_state.buffer.read(cx);
3016            let version = buffer.version();
3017            let non_text_state_update_count = buffer.non_text_state_update_count();
3018
3019            let buffer_edited = version.changed_since(&buffer_state.last_version);
3020            let buffer_non_text_state_updated =
3021                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
3022            if buffer_edited || buffer_non_text_state_updated {
3023                buffer_state.last_version = version;
3024                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
3025                excerpts_to_edit.extend(
3026                    buffer_state
3027                        .excerpts
3028                        .iter()
3029                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3030                );
3031            }
3032
3033            edited |= buffer_edited;
3034            non_text_state_updated |= buffer_non_text_state_updated;
3035            is_dirty |= buffer.is_dirty();
3036            has_deleted_file |= buffer
3037                .file()
3038                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3039            has_conflict |= buffer.has_conflict();
3040        }
3041        if edited {
3042            snapshot.edit_count += 1;
3043        }
3044        if non_text_state_updated {
3045            snapshot.non_text_state_update_count += 1;
3046        }
3047        snapshot.is_dirty = is_dirty;
3048        snapshot.has_deleted_file = has_deleted_file;
3049        snapshot.has_conflict = has_conflict;
3050
3051        for (id, diff) in self.diffs.iter() {
3052            if snapshot.diffs.get(id).is_none() {
3053                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3054            }
3055        }
3056
3057        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3058
3059        let mut edits = Vec::new();
3060        let mut new_excerpts = SumTree::default();
3061        let mut cursor = snapshot
3062            .excerpts
3063            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
3064
3065        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3066            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), &());
3067            let old_excerpt = cursor.item().unwrap();
3068            let buffer = buffer.read(cx);
3069            let buffer_id = buffer.remote_id();
3070
3071            let mut new_excerpt;
3072            if buffer_edited {
3073                edits.extend(
3074                    buffer
3075                        .edits_since_in_range::<usize>(
3076                            old_excerpt.buffer.version(),
3077                            old_excerpt.range.context.clone(),
3078                        )
3079                        .map(|edit| {
3080                            let excerpt_old_start = cursor.start().1;
3081                            let excerpt_new_start =
3082                                ExcerptOffset::new(new_excerpts.summary().text.len);
3083                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3084                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3085                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3086                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3087                            Edit {
3088                                old: old_start..old_end,
3089                                new: new_start..new_end,
3090                            }
3091                        }),
3092                );
3093
3094                new_excerpt = Excerpt::new(
3095                    old_excerpt.id,
3096                    locator.clone(),
3097                    buffer_id,
3098                    buffer.snapshot(),
3099                    old_excerpt.range.clone(),
3100                    old_excerpt.has_trailing_newline,
3101                );
3102            } else {
3103                new_excerpt = old_excerpt.clone();
3104                new_excerpt.buffer = buffer.snapshot();
3105            }
3106
3107            new_excerpts.push(new_excerpt, &());
3108            cursor.next();
3109        }
3110        new_excerpts.append(cursor.suffix(), &());
3111
3112        drop(cursor);
3113        snapshot.excerpts = new_excerpts;
3114
3115        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3116    }
3117
3118    fn sync_diff_transforms(
3119        &self,
3120        snapshot: &mut MultiBufferSnapshot,
3121        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3122        change_kind: DiffChangeKind,
3123    ) {
3124        if excerpt_edits.is_empty() {
3125            return;
3126        }
3127
3128        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3129        let mut old_diff_transforms = snapshot
3130            .diff_transforms
3131            .cursor::<Dimensions<ExcerptOffset, usize>>(&());
3132        let mut new_diff_transforms = SumTree::default();
3133        let mut old_expanded_hunks = HashSet::default();
3134        let mut output_edits = Vec::new();
3135        let mut output_delta = 0_isize;
3136        let mut at_transform_boundary = true;
3137        let mut end_of_current_insert = None;
3138
3139        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3140        while let Some(edit) = excerpt_edits.next() {
3141            excerpts.seek_forward(&edit.new.start, Bias::Right);
3142            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3143                excerpts.prev();
3144            }
3145
3146            // Keep any transforms that are before the edit.
3147            if at_transform_boundary {
3148                at_transform_boundary = false;
3149                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3150                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3151                if let Some(transform) = old_diff_transforms.item()
3152                    && old_diff_transforms.end().0 == edit.old.start
3153                    && old_diff_transforms.start().0 < edit.old.start
3154                {
3155                    self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3156                    old_diff_transforms.next();
3157                }
3158            }
3159
3160            // Compute the start of the edit in output coordinates.
3161            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3162            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3163            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3164
3165            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3166                &edit,
3167                &mut excerpts,
3168                &mut old_diff_transforms,
3169                &mut new_diff_transforms,
3170                &mut end_of_current_insert,
3171                &mut old_expanded_hunks,
3172                snapshot,
3173                change_kind,
3174            );
3175
3176            // Compute the end of the edit in output coordinates.
3177            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3178            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3179            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3180            let edit_new_end =
3181                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3182            let output_edit = Edit {
3183                old: edit_old_start..edit_old_end,
3184                new: edit_new_start..edit_new_end,
3185            };
3186
3187            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3188            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3189            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3190                output_edits.push(output_edit);
3191            }
3192
3193            // If this is the last edit that intersects the current diff transform,
3194            // then recreate the content up to the end of this transform, to prepare
3195            // for reusing additional slices of the old transforms.
3196            if excerpt_edits
3197                .peek()
3198                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3199            {
3200                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3201                    && match old_diff_transforms.item() {
3202                        Some(DiffTransform::BufferContent {
3203                            inserted_hunk_info: Some(hunk),
3204                            ..
3205                        }) => excerpts.item().is_some_and(|excerpt| {
3206                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3207                        }),
3208                        _ => true,
3209                    };
3210
3211                let mut excerpt_offset = edit.new.end;
3212                if !keep_next_old_transform {
3213                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3214                    old_diff_transforms.next();
3215                }
3216
3217                old_expanded_hunks.clear();
3218                self.push_buffer_content_transform(
3219                    snapshot,
3220                    &mut new_diff_transforms,
3221                    excerpt_offset,
3222                    end_of_current_insert,
3223                );
3224                at_transform_boundary = true;
3225            }
3226        }
3227
3228        // Keep any transforms that are after the last edit.
3229        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3230
3231        // Ensure there's always at least one buffer content transform.
3232        if new_diff_transforms.is_empty() {
3233            new_diff_transforms.push(
3234                DiffTransform::BufferContent {
3235                    summary: Default::default(),
3236                    inserted_hunk_info: None,
3237                },
3238                &(),
3239            );
3240        }
3241
3242        self.subscriptions.publish(output_edits);
3243        drop(old_diff_transforms);
3244        drop(excerpts);
3245        snapshot.diff_transforms = new_diff_transforms;
3246        snapshot.edit_count += 1;
3247
3248        #[cfg(any(test, feature = "test-support"))]
3249        snapshot.check_invariants();
3250    }
3251
3252    fn recompute_diff_transforms_for_edit(
3253        &self,
3254        edit: &Edit<TypedOffset<Excerpt>>,
3255        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3256        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
3257        new_diff_transforms: &mut SumTree<DiffTransform>,
3258        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3259        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3260        snapshot: &MultiBufferSnapshot,
3261        change_kind: DiffChangeKind,
3262    ) -> bool {
3263        log::trace!(
3264            "recomputing diff transform for edit {:?} => {:?}",
3265            edit.old.start.value..edit.old.end.value,
3266            edit.new.start.value..edit.new.end.value
3267        );
3268
3269        // Record which hunks were previously expanded.
3270        while let Some(item) = old_diff_transforms.item() {
3271            if let Some(hunk_info) = item.hunk_info() {
3272                log::trace!(
3273                    "previously expanded hunk at {}",
3274                    old_diff_transforms.start().0
3275                );
3276                old_expanded_hunks.insert(hunk_info);
3277            }
3278            if old_diff_transforms.end().0 > edit.old.end {
3279                break;
3280            }
3281            old_diff_transforms.next();
3282        }
3283
3284        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3285        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3286        if old_expanded_hunks.is_empty()
3287            && change_kind == DiffChangeKind::BufferEdited
3288            && !all_diff_hunks_expanded
3289        {
3290            return false;
3291        }
3292
3293        // Visit each excerpt that intersects the edit.
3294        let mut did_expand_hunks = false;
3295        while let Some(excerpt) = excerpts.item() {
3296            // Recompute the expanded hunks in the portion of the excerpt that
3297            // intersects the edit.
3298            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3299                let buffer = &excerpt.buffer;
3300                let excerpt_start = *excerpts.start();
3301                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3302                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3303                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3304                let edit_buffer_start =
3305                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3306                let edit_buffer_end =
3307                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3308                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3309                let edit_anchor_range =
3310                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3311
3312                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3313                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3314                        continue;
3315                    }
3316
3317                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3318                    if hunk_buffer_range.start < excerpt_buffer_start {
3319                        log::trace!("skipping hunk that starts before excerpt");
3320                        continue;
3321                    }
3322
3323                    let hunk_info = DiffTransformHunkInfo {
3324                        excerpt_id: excerpt.id,
3325                        hunk_start_anchor: hunk.buffer_range.start,
3326                        hunk_secondary_status: hunk.secondary_status,
3327                    };
3328
3329                    let hunk_excerpt_start = excerpt_start
3330                        + ExcerptOffset::new(
3331                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3332                        );
3333                    let hunk_excerpt_end = excerpt_end.min(
3334                        excerpt_start
3335                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3336                    );
3337
3338                    self.push_buffer_content_transform(
3339                        snapshot,
3340                        new_diff_transforms,
3341                        hunk_excerpt_start,
3342                        *end_of_current_insert,
3343                    );
3344
3345                    // For every existing hunk, determine if it was previously expanded
3346                    // and if it should currently be expanded.
3347                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3348                    let should_expand_hunk = match &change_kind {
3349                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3350                            was_previously_expanded || all_diff_hunks_expanded
3351                        }
3352                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3353                            let intersects = hunk_buffer_range.is_empty()
3354                                || hunk_buffer_range.end > edit_buffer_start;
3355                            if *expand {
3356                                intersects || was_previously_expanded || all_diff_hunks_expanded
3357                            } else {
3358                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3359                            }
3360                        }
3361                        _ => was_previously_expanded || all_diff_hunks_expanded,
3362                    };
3363
3364                    if should_expand_hunk {
3365                        did_expand_hunks = true;
3366                        log::trace!(
3367                            "expanding hunk {:?}, excerpt:{:?}",
3368                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3369                            excerpt.id
3370                        );
3371
3372                        if !hunk.diff_base_byte_range.is_empty()
3373                            && hunk_buffer_range.start >= edit_buffer_start
3374                            && hunk_buffer_range.start <= excerpt_buffer_end
3375                        {
3376                            let base_text = diff.base_text();
3377                            let mut text_cursor =
3378                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3379                            let mut base_text_summary =
3380                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3381
3382                            let mut has_trailing_newline = false;
3383                            if base_text_summary.last_line_chars > 0 {
3384                                base_text_summary += TextSummary::newline();
3385                                has_trailing_newline = true;
3386                            }
3387
3388                            new_diff_transforms.push(
3389                                DiffTransform::DeletedHunk {
3390                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3391                                    summary: base_text_summary,
3392                                    buffer_id: excerpt.buffer_id,
3393                                    hunk_info,
3394                                    has_trailing_newline,
3395                                },
3396                                &(),
3397                            );
3398                        }
3399
3400                        if !hunk_buffer_range.is_empty() {
3401                            *end_of_current_insert =
3402                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3403                        }
3404                    }
3405                }
3406            }
3407
3408            if excerpts.end() <= edit.new.end {
3409                excerpts.next();
3410            } else {
3411                break;
3412            }
3413        }
3414
3415        did_expand_hunks || !old_expanded_hunks.is_empty()
3416    }
3417
3418    fn append_diff_transforms(
3419        &self,
3420        new_transforms: &mut SumTree<DiffTransform>,
3421        subtree: SumTree<DiffTransform>,
3422    ) {
3423        if let Some(DiffTransform::BufferContent {
3424            inserted_hunk_info,
3425            summary,
3426        }) = subtree.first()
3427            && self.extend_last_buffer_content_transform(
3428                new_transforms,
3429                *inserted_hunk_info,
3430                *summary,
3431            )
3432        {
3433            let mut cursor = subtree.cursor::<()>(&());
3434            cursor.next();
3435            cursor.next();
3436            new_transforms.append(cursor.suffix(), &());
3437            return;
3438        }
3439        new_transforms.append(subtree, &());
3440    }
3441
3442    fn push_diff_transform(
3443        &self,
3444        new_transforms: &mut SumTree<DiffTransform>,
3445        transform: DiffTransform,
3446    ) {
3447        if let DiffTransform::BufferContent {
3448            inserted_hunk_info: inserted_hunk_anchor,
3449            summary,
3450        } = transform
3451            && self.extend_last_buffer_content_transform(
3452                new_transforms,
3453                inserted_hunk_anchor,
3454                summary,
3455            )
3456        {
3457            return;
3458        }
3459        new_transforms.push(transform, &());
3460    }
3461
3462    fn push_buffer_content_transform(
3463        &self,
3464        old_snapshot: &MultiBufferSnapshot,
3465        new_transforms: &mut SumTree<DiffTransform>,
3466        end_offset: ExcerptOffset,
3467        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3468    ) {
3469        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3470            (end_offset.min(insertion_end_offset), Some(hunk_info))
3471        });
3472        let unchanged_region = [(end_offset, None)];
3473
3474        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3475        {
3476            let start_offset = new_transforms.summary().excerpt_len();
3477            if end_offset <= start_offset {
3478                continue;
3479            }
3480            let summary_to_add = old_snapshot
3481                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3482
3483            if !self.extend_last_buffer_content_transform(
3484                new_transforms,
3485                inserted_hunk_info,
3486                summary_to_add,
3487            ) {
3488                new_transforms.push(
3489                    DiffTransform::BufferContent {
3490                        summary: summary_to_add,
3491                        inserted_hunk_info,
3492                    },
3493                    &(),
3494                )
3495            }
3496        }
3497    }
3498
3499    fn extend_last_buffer_content_transform(
3500        &self,
3501        new_transforms: &mut SumTree<DiffTransform>,
3502        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3503        summary_to_add: TextSummary,
3504    ) -> bool {
3505        let mut did_extend = false;
3506        new_transforms.update_last(
3507            |last_transform| {
3508                if let DiffTransform::BufferContent {
3509                    summary,
3510                    inserted_hunk_info: inserted_hunk_anchor,
3511                } = last_transform
3512                    && *inserted_hunk_anchor == new_inserted_hunk_info
3513                {
3514                    *summary += summary_to_add;
3515                    did_extend = true;
3516                }
3517            },
3518            &(),
3519        );
3520        did_extend
3521    }
3522}
3523
3524fn build_excerpt_ranges(
3525    ranges: impl IntoIterator<Item = Range<Point>>,
3526    context_line_count: u32,
3527    buffer_snapshot: &BufferSnapshot,
3528) -> Vec<ExcerptRange<Point>> {
3529    ranges
3530        .into_iter()
3531        .map(|range| {
3532            let start_row = range.start.row.saturating_sub(context_line_count);
3533            let start = Point::new(start_row, 0);
3534            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3535            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3536            ExcerptRange {
3537                context: start..end,
3538                primary: range,
3539            }
3540        })
3541        .collect()
3542}
3543
3544#[cfg(any(test, feature = "test-support"))]
3545impl MultiBuffer {
3546    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3547        let buffer = cx.new(|cx| Buffer::local(text, cx));
3548        cx.new(|cx| Self::singleton(buffer, cx))
3549    }
3550
3551    pub fn build_multi<const COUNT: usize>(
3552        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3553        cx: &mut gpui::App,
3554    ) -> Entity<Self> {
3555        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3556        for (text, ranges) in excerpts {
3557            let buffer = cx.new(|cx| Buffer::local(text, cx));
3558            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3559            multi.update(cx, |multi, cx| {
3560                multi.push_excerpts(buffer, excerpt_ranges, cx)
3561            });
3562        }
3563
3564        multi
3565    }
3566
3567    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3568        cx.new(|cx| Self::singleton(buffer, cx))
3569    }
3570
3571    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3572        cx.new(|cx| {
3573            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3574            let mutation_count = rng.random_range(1..=5);
3575            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3576            multibuffer
3577        })
3578    }
3579
3580    pub fn randomly_edit(
3581        &mut self,
3582        rng: &mut impl rand::Rng,
3583        edit_count: usize,
3584        cx: &mut Context<Self>,
3585    ) {
3586        use util::RandomCharIter;
3587
3588        let snapshot = self.read(cx);
3589        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3590        let mut last_end = None;
3591        for _ in 0..edit_count {
3592            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3593                break;
3594            }
3595
3596            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3597            let end =
3598                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3599            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3600            last_end = Some(end);
3601
3602            let mut range = start..end;
3603            if rng.random_bool(0.2) {
3604                mem::swap(&mut range.start, &mut range.end);
3605            }
3606
3607            let new_text_len = rng.random_range(0..10);
3608            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3609
3610            edits.push((range, new_text.into()));
3611        }
3612        log::info!("mutating multi-buffer with {:?}", edits);
3613        drop(snapshot);
3614
3615        self.edit(edits, None, cx);
3616    }
3617
3618    pub fn randomly_edit_excerpts(
3619        &mut self,
3620        rng: &mut impl rand::Rng,
3621        mutation_count: usize,
3622        cx: &mut Context<Self>,
3623    ) {
3624        use rand::prelude::*;
3625        use std::env;
3626        use util::RandomCharIter;
3627
3628        let max_excerpts = env::var("MAX_EXCERPTS")
3629            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3630            .unwrap_or(5);
3631
3632        let mut buffers = Vec::new();
3633        for _ in 0..mutation_count {
3634            if rng.random_bool(0.05) {
3635                log::info!("Clearing multi-buffer");
3636                self.clear(cx);
3637                continue;
3638            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3639                let ids = self.excerpt_ids();
3640                let mut excerpts = HashSet::default();
3641                for _ in 0..rng.random_range(0..ids.len()) {
3642                    excerpts.extend(ids.choose(rng).copied());
3643                }
3644
3645                let line_count = rng.random_range(0..5);
3646
3647                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3648
3649                self.expand_excerpts(
3650                    excerpts.iter().cloned(),
3651                    line_count,
3652                    ExpandExcerptDirection::UpAndDown,
3653                    cx,
3654                );
3655                continue;
3656            }
3657
3658            let excerpt_ids = self.excerpt_ids();
3659            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3660                let buffer_handle = if rng.random() || self.buffers.borrow().is_empty() {
3661                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3662                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3663                    let buffer = buffers.last().unwrap().read(cx);
3664                    log::info!(
3665                        "Creating new buffer {} with text: {:?}",
3666                        buffer.remote_id(),
3667                        buffer.text()
3668                    );
3669                    buffers.last().unwrap().clone()
3670                } else {
3671                    self.buffers
3672                        .borrow()
3673                        .values()
3674                        .choose(rng)
3675                        .unwrap()
3676                        .buffer
3677                        .clone()
3678                };
3679
3680                let buffer = buffer_handle.read(cx);
3681                let buffer_text = buffer.text();
3682                let ranges = (0..rng.random_range(0..5))
3683                    .map(|_| {
3684                        let end_ix =
3685                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3686                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3687                        ExcerptRange::new(start_ix..end_ix)
3688                    })
3689                    .collect::<Vec<_>>();
3690                log::info!(
3691                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3692                    buffer_handle.read(cx).remote_id(),
3693                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3694                    ranges
3695                        .iter()
3696                        .map(|r| &buffer_text[r.context.clone()])
3697                        .collect::<Vec<_>>()
3698                );
3699
3700                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3701                log::info!("Inserted with ids: {:?}", excerpt_id);
3702            } else {
3703                let remove_count = rng.random_range(1..=excerpt_ids.len());
3704                let mut excerpts_to_remove = excerpt_ids
3705                    .choose_multiple(rng, remove_count)
3706                    .cloned()
3707                    .collect::<Vec<_>>();
3708                let snapshot = self.snapshot.borrow();
3709                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3710                drop(snapshot);
3711                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3712                self.remove_excerpts(excerpts_to_remove, cx);
3713            }
3714        }
3715    }
3716
3717    pub fn randomly_mutate(
3718        &mut self,
3719        rng: &mut impl rand::Rng,
3720        mutation_count: usize,
3721        cx: &mut Context<Self>,
3722    ) {
3723        use rand::prelude::*;
3724
3725        if rng.random_bool(0.7) || self.singleton {
3726            let buffer = self
3727                .buffers
3728                .borrow()
3729                .values()
3730                .choose(rng)
3731                .map(|state| state.buffer.clone());
3732
3733            if let Some(buffer) = buffer {
3734                buffer.update(cx, |buffer, cx| {
3735                    if rng.random() {
3736                        buffer.randomly_edit(rng, mutation_count, cx);
3737                    } else {
3738                        buffer.randomly_undo_redo(rng, cx);
3739                    }
3740                });
3741            } else {
3742                self.randomly_edit(rng, mutation_count, cx);
3743            }
3744        } else {
3745            self.randomly_edit_excerpts(rng, mutation_count, cx);
3746        }
3747
3748        self.check_invariants(cx);
3749    }
3750
3751    fn check_invariants(&self, cx: &App) {
3752        self.read(cx).check_invariants();
3753    }
3754}
3755
3756impl EventEmitter<Event> for MultiBuffer {}
3757
3758impl MultiBufferSnapshot {
3759    pub fn text(&self) -> String {
3760        self.chunks(0..self.len(), false)
3761            .map(|chunk| chunk.text)
3762            .collect()
3763    }
3764
3765    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3766        self.reversed_chunks_in_range(0..position.to_offset(self))
3767            .flat_map(|c| c.chars().rev())
3768    }
3769
3770    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3771        let mut cursor = self.cursor::<usize>();
3772        cursor.seek(&range.end);
3773        let current_chunks = cursor.region().as_ref().map(|region| {
3774            let start_overshoot = range.start.saturating_sub(region.range.start);
3775            let end_overshoot = range.end - region.range.start;
3776            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3777            let start = region.buffer_range.start + start_overshoot;
3778            region.buffer.reversed_chunks_in_range(start..end)
3779        });
3780        ReversedMultiBufferChunks {
3781            cursor,
3782            current_chunks,
3783            start: range.start,
3784            offset: range.end,
3785        }
3786    }
3787
3788    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3789        let offset = position.to_offset(self);
3790        self.text_for_range(offset..self.len())
3791            .flat_map(|chunk| chunk.chars())
3792    }
3793
3794    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3795        self.chunks(range, false).map(|chunk| chunk.text)
3796    }
3797
3798    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3799        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3800            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3801    }
3802
3803    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3804    where
3805        T: ToOffset,
3806    {
3807        let position = position.to_offset(self);
3808        position == self.clip_offset(position, Bias::Left)
3809            && self
3810                .bytes_in_range(position..self.len())
3811                .flatten()
3812                .copied()
3813                .take(needle.len())
3814                .eq(needle.bytes())
3815    }
3816
3817    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3818        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3819    }
3820
3821    pub fn diff_hunks_in_range<T: ToPoint>(
3822        &self,
3823        range: Range<T>,
3824    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3825        let query_range = range.start.to_point(self)..range.end.to_point(self);
3826        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3827            let diff = self.diffs.get(&buffer.remote_id())?;
3828            let buffer_start = buffer.anchor_before(buffer_range.start);
3829            let buffer_end = buffer.anchor_after(buffer_range.end);
3830            Some(
3831                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3832                    .filter_map(|hunk| {
3833                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3834                            return None;
3835                        }
3836                        Some((hunk.range.clone(), hunk))
3837                    }),
3838            )
3839        })
3840        .filter_map(move |(range, hunk, excerpt)| {
3841            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3842            {
3843                return None;
3844            }
3845            let end_row = if range.end.column == 0 {
3846                range.end.row
3847            } else {
3848                range.end.row + 1
3849            };
3850            Some(MultiBufferDiffHunk {
3851                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3852                buffer_id: excerpt.buffer_id,
3853                excerpt_id: excerpt.id,
3854                buffer_range: hunk.buffer_range.clone(),
3855                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3856                secondary_status: hunk.secondary_status,
3857            })
3858        })
3859    }
3860
3861    pub fn excerpt_ids_for_range<T: ToOffset>(
3862        &self,
3863        range: Range<T>,
3864    ) -> impl Iterator<Item = ExcerptId> + '_ {
3865        let range = range.start.to_offset(self)..range.end.to_offset(self);
3866        let mut cursor = self.cursor::<usize>();
3867        cursor.seek(&range.start);
3868        std::iter::from_fn(move || {
3869            let region = cursor.region()?;
3870            if region.range.start >= range.end {
3871                return None;
3872            }
3873            cursor.next_excerpt();
3874            Some(region.excerpt.id)
3875        })
3876    }
3877
3878    pub fn buffer_ids_for_range<T: ToOffset>(
3879        &self,
3880        range: Range<T>,
3881    ) -> impl Iterator<Item = BufferId> + '_ {
3882        let range = range.start.to_offset(self)..range.end.to_offset(self);
3883        let mut cursor = self.cursor::<usize>();
3884        cursor.seek(&range.start);
3885        std::iter::from_fn(move || {
3886            let region = cursor.region()?;
3887            if region.range.start > range.end
3888                || region.range.start == range.end && region.range.start > range.start
3889            {
3890                return None;
3891            }
3892            cursor.next_excerpt();
3893            Some(region.excerpt.buffer_id)
3894        })
3895    }
3896
3897    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3898        &self,
3899        ranges: impl Iterator<Item = Range<T>>,
3900    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3901        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3902    }
3903
3904    pub fn range_to_buffer_ranges<T: ToOffset>(
3905        &self,
3906        range: Range<T>,
3907    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3908        let start = range.start.to_offset(self);
3909        let end = range.end.to_offset(self);
3910
3911        let mut cursor = self.cursor::<usize>();
3912        cursor.seek(&start);
3913
3914        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3915        while let Some(region) = cursor.region() {
3916            if region.range.start > end {
3917                break;
3918            }
3919            if region.is_main_buffer {
3920                let start_overshoot = start.saturating_sub(region.range.start);
3921                let end_overshoot = end.saturating_sub(region.range.start);
3922                let start = region
3923                    .buffer_range
3924                    .end
3925                    .min(region.buffer_range.start + start_overshoot);
3926                let end = region
3927                    .buffer_range
3928                    .end
3929                    .min(region.buffer_range.start + end_overshoot);
3930                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3931                    *excerpt_id == region.excerpt.id && prev_range.end == start
3932                }) {
3933                    prev.1.end = end;
3934                } else {
3935                    result.push((region.buffer, start..end, region.excerpt.id));
3936                }
3937            }
3938            cursor.next();
3939        }
3940        result
3941    }
3942
3943    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3944        &self,
3945        range: Range<T>,
3946    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3947        let start = range.start.to_offset(self);
3948        let end = range.end.to_offset(self);
3949
3950        let mut cursor = self.cursor::<usize>();
3951        cursor.seek(&start);
3952
3953        std::iter::from_fn(move || {
3954            let region = cursor.region()?;
3955            if region.range.start > end {
3956                return None;
3957            }
3958            let start_overshoot = start.saturating_sub(region.range.start);
3959            let end_overshoot = end.saturating_sub(region.range.start);
3960            let start = region
3961                .buffer_range
3962                .end
3963                .min(region.buffer_range.start + start_overshoot);
3964            let end = region
3965                .buffer_range
3966                .end
3967                .min(region.buffer_range.start + end_overshoot);
3968
3969            let region_excerpt_id = region.excerpt.id;
3970            let deleted_hunk_anchor = if region.is_main_buffer {
3971                None
3972            } else {
3973                Some(self.anchor_before(region.range.start))
3974            };
3975            let result = (
3976                region.buffer,
3977                start..end,
3978                region_excerpt_id,
3979                deleted_hunk_anchor,
3980            );
3981            cursor.next();
3982            Some(result)
3983        })
3984    }
3985
3986    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3987    /// coordinates.
3988    ///
3989    /// The given callback will be called for every excerpt intersecting the given range. It will
3990    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3991    /// The callback should return an iterator of metadata items from that buffer, each paired
3992    /// with a buffer range.
3993    ///
3994    /// The returned iterator yields each of these metadata items, paired with its range in
3995    /// multi-buffer coordinates.
3996    fn lift_buffer_metadata<'a, D, M, I>(
3997        &'a self,
3998        query_range: Range<D>,
3999        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
4000    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
4001    where
4002        I: Iterator<Item = (Range<D>, M)> + 'a,
4003        D: TextDimension + Ord + Sub<D, Output = D>,
4004    {
4005        let max_position = D::from_text_summary(&self.text_summary());
4006        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4007        let mut cursor = self.cursor::<D>();
4008
4009        // Find the excerpt and buffer offset where the given range ends.
4010        cursor.seek(&query_range.end);
4011        let mut range_end = None;
4012        while let Some(region) = cursor.region() {
4013            if region.is_main_buffer {
4014                let mut buffer_end = region.buffer_range.start;
4015                let overshoot = if query_range.end > region.range.start {
4016                    query_range.end - region.range.start
4017                } else {
4018                    D::default()
4019                };
4020                buffer_end.add_assign(&overshoot);
4021                range_end = Some((region.excerpt.id, buffer_end));
4022                break;
4023            }
4024            cursor.next();
4025        }
4026
4027        cursor.seek(&query_range.start);
4028
4029        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4030            && region.range.start > D::zero(&())
4031        {
4032            cursor.prev()
4033        }
4034
4035        iter::from_fn(move || {
4036            loop {
4037                let excerpt = cursor.excerpt()?;
4038
4039                // If we have already retrieved metadata for this excerpt, continue to use it.
4040                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4041                    .as_mut()
4042                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4043                {
4044                    Some(metadata)
4045                }
4046                // Otherwise, compute the intersection of the input range with the excerpt's range,
4047                // and retrieve the metadata for the resulting range.
4048                else {
4049                    let region = cursor.region()?;
4050                    let mut buffer_start;
4051                    if region.is_main_buffer {
4052                        buffer_start = region.buffer_range.start;
4053                        if query_range.start > region.range.start {
4054                            let overshoot = query_range.start - region.range.start;
4055                            buffer_start.add_assign(&overshoot);
4056                        }
4057                        buffer_start = buffer_start.min(region.buffer_range.end);
4058                    } else {
4059                        buffer_start = cursor.main_buffer_position()?;
4060                    };
4061                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4062                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4063                        && excerpt.id == end_excerpt_id
4064                    {
4065                        buffer_end = buffer_end.min(end_buffer_offset);
4066                    }
4067
4068                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4069                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4070                    })
4071                };
4072
4073                // Visit each metadata item.
4074                if let Some((metadata_buffer_range, metadata)) =
4075                    metadata_iter.and_then(Iterator::next)
4076                {
4077                    // Find the multibuffer regions that contain the start and end of
4078                    // the metadata item's range.
4079                    if metadata_buffer_range.start > D::default() {
4080                        while let Some(region) = cursor.region() {
4081                            if region.is_main_buffer
4082                                && (region.buffer_range.end >= metadata_buffer_range.start
4083                                    || cursor.is_at_end_of_excerpt())
4084                            {
4085                                break;
4086                            }
4087                            cursor.next();
4088                        }
4089                    }
4090                    let start_region = cursor.region()?;
4091                    while let Some(region) = cursor.region() {
4092                        if region.is_main_buffer
4093                            && (region.buffer_range.end > metadata_buffer_range.end
4094                                || cursor.is_at_end_of_excerpt())
4095                        {
4096                            break;
4097                        }
4098                        cursor.next();
4099                    }
4100                    let end_region = cursor.region();
4101
4102                    // Convert the metadata item's range into multibuffer coordinates.
4103                    let mut start_position = start_region.range.start;
4104                    let region_buffer_start = start_region.buffer_range.start;
4105                    if start_region.is_main_buffer
4106                        && metadata_buffer_range.start > region_buffer_start
4107                    {
4108                        start_position
4109                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4110                        start_position = start_position.min(start_region.range.end);
4111                    }
4112
4113                    let mut end_position = max_position;
4114                    if let Some(end_region) = &end_region {
4115                        end_position = end_region.range.start;
4116                        debug_assert!(end_region.is_main_buffer);
4117                        let region_buffer_start = end_region.buffer_range.start;
4118                        if metadata_buffer_range.end > region_buffer_start {
4119                            end_position
4120                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4121                        }
4122                        end_position = end_position.min(end_region.range.end);
4123                    }
4124
4125                    if start_position <= query_range.end && end_position >= query_range.start {
4126                        return Some((start_position..end_position, metadata, excerpt));
4127                    }
4128                }
4129                // When there are no more metadata items for this excerpt, move to the next excerpt.
4130                else {
4131                    current_excerpt_metadata.take();
4132                    if let Some((end_excerpt_id, _)) = range_end
4133                        && excerpt.id == end_excerpt_id
4134                    {
4135                        return None;
4136                    }
4137                    cursor.next_excerpt();
4138                }
4139            }
4140        })
4141    }
4142
4143    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4144        let offset = position.to_offset(self);
4145
4146        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4147        cursor.seek(&DimensionPair {
4148            key: offset,
4149            value: None,
4150        });
4151        cursor.seek_to_start_of_current_excerpt();
4152        let excerpt = cursor.excerpt()?;
4153
4154        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4155        let current_position = self
4156            .anchor_before(offset)
4157            .text_anchor
4158            .to_offset(&excerpt.buffer);
4159        let excerpt_end = excerpt
4160            .buffer
4161            .anchor_before(excerpt_end.min(current_position));
4162
4163        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4164            for hunk in diff.hunks_intersecting_range_rev(
4165                excerpt.range.context.start..excerpt_end,
4166                &excerpt.buffer,
4167            ) {
4168                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4169                if hunk_end >= current_position {
4170                    continue;
4171                }
4172                let start =
4173                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4174                        .to_point(self);
4175                return Some(MultiBufferRow(start.row));
4176            }
4177        }
4178
4179        loop {
4180            cursor.prev_excerpt();
4181            let excerpt = cursor.excerpt()?;
4182
4183            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4184                continue;
4185            };
4186            let mut hunks =
4187                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4188            let Some(hunk) = hunks.next() else {
4189                continue;
4190            };
4191            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4192                .to_point(self);
4193            return Some(MultiBufferRow(start.row));
4194        }
4195    }
4196
4197    pub fn has_diff_hunks(&self) -> bool {
4198        self.diffs.values().any(|diff| !diff.is_empty())
4199    }
4200
4201    pub fn is_inside_word<T: ToOffset>(&self, position: T, for_completion: bool) -> bool {
4202        let position = position.to_offset(self);
4203        let classifier = self
4204            .char_classifier_at(position)
4205            .for_completion(for_completion);
4206        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4207        let prev_char_kind = self
4208            .reversed_chars_at(position)
4209            .next()
4210            .map(|c| classifier.kind(c));
4211        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4212    }
4213
4214    pub fn surrounding_word<T: ToOffset>(
4215        &self,
4216        start: T,
4217        for_completion: bool,
4218    ) -> (Range<usize>, Option<CharKind>) {
4219        let mut start = start.to_offset(self);
4220        let mut end = start;
4221        let mut next_chars = self.chars_at(start).peekable();
4222        let mut prev_chars = self.reversed_chars_at(start).peekable();
4223
4224        let classifier = self
4225            .char_classifier_at(start)
4226            .for_completion(for_completion);
4227
4228        let word_kind = cmp::max(
4229            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4230            next_chars.peek().copied().map(|c| classifier.kind(c)),
4231        );
4232
4233        for ch in prev_chars {
4234            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4235                start -= ch.len_utf8();
4236            } else {
4237                break;
4238            }
4239        }
4240
4241        for ch in next_chars {
4242            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4243                end += ch.len_utf8();
4244            } else {
4245                break;
4246            }
4247        }
4248
4249        (start..end, word_kind)
4250    }
4251
4252    pub fn char_kind_before<T: ToOffset>(
4253        &self,
4254        start: T,
4255        for_completion: bool,
4256    ) -> Option<CharKind> {
4257        let start = start.to_offset(self);
4258        let classifier = self
4259            .char_classifier_at(start)
4260            .for_completion(for_completion);
4261        self.reversed_chars_at(start)
4262            .next()
4263            .map(|ch| classifier.kind(ch))
4264    }
4265
4266    pub fn is_singleton(&self) -> bool {
4267        self.singleton
4268    }
4269
4270    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4271        if self.singleton {
4272            self.excerpts
4273                .iter()
4274                .next()
4275                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4276        } else {
4277            None
4278        }
4279    }
4280
4281    pub fn len(&self) -> usize {
4282        self.diff_transforms.summary().output.len
4283    }
4284
4285    pub fn is_empty(&self) -> bool {
4286        self.excerpts.summary().text.len == 0
4287    }
4288
4289    pub fn widest_line_number(&self) -> u32 {
4290        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4291        self.excerpts.summary().widest_line_number + 1
4292    }
4293
4294    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4295        let range = range.start.to_offset(self)..range.end.to_offset(self);
4296        let mut excerpts = self.cursor::<usize>();
4297        excerpts.seek(&range.start);
4298
4299        let mut chunk;
4300        let mut has_trailing_newline;
4301        let excerpt_bytes;
4302        if let Some(region) = excerpts.region() {
4303            let mut bytes = region.buffer.bytes_in_range(
4304                region.buffer_range.start + range.start - region.range.start
4305                    ..(region.buffer_range.start + range.end - region.range.start)
4306                        .min(region.buffer_range.end),
4307            );
4308            chunk = bytes.next().unwrap_or(&[][..]);
4309            excerpt_bytes = Some(bytes);
4310            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4311            if chunk.is_empty() && has_trailing_newline {
4312                chunk = b"\n";
4313                has_trailing_newline = false;
4314            }
4315        } else {
4316            chunk = &[][..];
4317            excerpt_bytes = None;
4318            has_trailing_newline = false;
4319        };
4320
4321        MultiBufferBytes {
4322            range,
4323            cursor: excerpts,
4324            excerpt_bytes,
4325            has_trailing_newline,
4326            chunk,
4327        }
4328    }
4329
4330    pub fn reversed_bytes_in_range<T: ToOffset>(
4331        &self,
4332        range: Range<T>,
4333    ) -> ReversedMultiBufferBytes<'_> {
4334        let range = range.start.to_offset(self)..range.end.to_offset(self);
4335        let mut chunks = self.reversed_chunks_in_range(range.clone());
4336        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4337        ReversedMultiBufferBytes {
4338            range,
4339            chunks,
4340            chunk,
4341        }
4342    }
4343
4344    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4345        let mut cursor = self.cursor::<Point>();
4346        cursor.seek(&Point::new(start_row.0, 0));
4347        let mut result = MultiBufferRows {
4348            point: Point::new(0, 0),
4349            is_empty: self.excerpts.is_empty(),
4350            is_singleton: self.is_singleton(),
4351            cursor,
4352        };
4353        result.seek(start_row);
4354        result
4355    }
4356
4357    pub fn chunks<T: ToOffset>(
4358        &self,
4359        range: Range<T>,
4360        language_aware: bool,
4361    ) -> MultiBufferChunks<'_> {
4362        let mut chunks = MultiBufferChunks {
4363            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4364            range: 0..0,
4365            excerpts: self.excerpts.cursor(&()),
4366            diff_transforms: self.diff_transforms.cursor(&()),
4367            diffs: &self.diffs,
4368            diff_base_chunks: None,
4369            excerpt_chunks: None,
4370            buffer_chunk: None,
4371            language_aware,
4372        };
4373        let range = range.start.to_offset(self)..range.end.to_offset(self);
4374        chunks.seek(range);
4375        chunks
4376    }
4377
4378    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4379        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4380    }
4381
4382    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4383        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4384    }
4385
4386    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4387        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4388    }
4389
4390    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4391        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4392            buffer.clip_point_utf16(Unclipped(point), bias)
4393        })
4394    }
4395
4396    pub fn offset_to_point(&self, offset: usize) -> Point {
4397        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4398    }
4399
4400    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4401        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4402    }
4403
4404    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4405        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4406    }
4407
4408    pub fn point_to_offset(&self, point: Point) -> usize {
4409        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4410    }
4411
4412    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4413        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4414    }
4415
4416    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4417        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4418    }
4419
4420    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4421        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4422    }
4423
4424    fn clip_dimension<D>(
4425        &self,
4426        position: D,
4427        bias: Bias,
4428        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4429    ) -> D
4430    where
4431        D: TextDimension + Ord + Sub<D, Output = D>,
4432    {
4433        let mut cursor = self.cursor();
4434        cursor.seek(&position);
4435        if let Some(region) = cursor.region() {
4436            if position >= region.range.end {
4437                return region.range.end;
4438            }
4439            let overshoot = position - region.range.start;
4440            let mut buffer_position = region.buffer_range.start;
4441            buffer_position.add_assign(&overshoot);
4442            let clipped_buffer_position =
4443                clip_buffer_position(region.buffer, buffer_position, bias);
4444            let mut position = region.range.start;
4445            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4446            position
4447        } else {
4448            D::from_text_summary(&self.text_summary())
4449        }
4450    }
4451
4452    fn convert_dimension<D1, D2>(
4453        &self,
4454        key: D1,
4455        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4456    ) -> D2
4457    where
4458        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4459        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4460    {
4461        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4462        cursor.seek(&DimensionPair { key, value: None });
4463        if let Some(region) = cursor.region() {
4464            if key >= region.range.end.key {
4465                return region.range.end.value.unwrap();
4466            }
4467            let start_key = region.range.start.key;
4468            let start_value = region.range.start.value.unwrap();
4469            let buffer_start_key = region.buffer_range.start.key;
4470            let buffer_start_value = region.buffer_range.start.value.unwrap();
4471            let mut buffer_key = buffer_start_key;
4472            buffer_key.add_assign(&(key - start_key));
4473            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4474            let mut result = start_value;
4475            result.add_assign(&(buffer_value - buffer_start_value));
4476            result
4477        } else {
4478            D2::from_text_summary(&self.text_summary())
4479        }
4480    }
4481
4482    pub fn point_to_buffer_offset<T: ToOffset>(
4483        &self,
4484        point: T,
4485    ) -> Option<(&BufferSnapshot, usize)> {
4486        let offset = point.to_offset(self);
4487        let mut cursor = self.cursor::<usize>();
4488        cursor.seek(&offset);
4489        let region = cursor.region()?;
4490        let overshoot = offset - region.range.start;
4491        let buffer_offset = region.buffer_range.start + overshoot;
4492        if buffer_offset == region.buffer.len() + 1
4493            && region.has_trailing_newline
4494            && !region.is_main_buffer
4495        {
4496            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4497        } else if buffer_offset > region.buffer.len() {
4498            return None;
4499        }
4500        Some((region.buffer, buffer_offset))
4501    }
4502
4503    pub fn point_to_buffer_point(
4504        &self,
4505        point: Point,
4506    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4507        let mut cursor = self.cursor::<Point>();
4508        cursor.seek(&point);
4509        let region = cursor.region()?;
4510        let overshoot = point - region.range.start;
4511        let buffer_point = region.buffer_range.start + overshoot;
4512        let excerpt = cursor.excerpt()?;
4513        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4514            && region.has_trailing_newline
4515            && !region.is_main_buffer
4516        {
4517            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4518        } else if buffer_point > region.buffer.max_point() {
4519            return None;
4520        }
4521        Some((region.buffer, buffer_point, excerpt.id))
4522    }
4523
4524    pub fn suggested_indents(
4525        &self,
4526        rows: impl IntoIterator<Item = u32>,
4527        cx: &App,
4528    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4529        let mut result = BTreeMap::new();
4530
4531        let mut rows_for_excerpt = Vec::new();
4532        let mut cursor = self.cursor::<Point>();
4533        let mut rows = rows.into_iter().peekable();
4534        let mut prev_row = u32::MAX;
4535        let mut prev_language_indent_size = IndentSize::default();
4536
4537        while let Some(row) = rows.next() {
4538            cursor.seek(&Point::new(row, 0));
4539            let Some(region) = cursor.region() else {
4540                continue;
4541            };
4542
4543            // Retrieve the language and indent size once for each disjoint region being indented.
4544            let single_indent_size = if row.saturating_sub(1) == prev_row {
4545                prev_language_indent_size
4546            } else {
4547                region
4548                    .buffer
4549                    .language_indent_size_at(Point::new(row, 0), cx)
4550            };
4551            prev_language_indent_size = single_indent_size;
4552            prev_row = row;
4553
4554            let start_buffer_row = region.buffer_range.start.row;
4555            let start_multibuffer_row = region.range.start.row;
4556            let end_multibuffer_row = region.range.end.row;
4557
4558            rows_for_excerpt.push(row);
4559            while let Some(next_row) = rows.peek().copied() {
4560                if end_multibuffer_row > next_row {
4561                    rows_for_excerpt.push(next_row);
4562                    rows.next();
4563                } else {
4564                    break;
4565                }
4566            }
4567
4568            let buffer_rows = rows_for_excerpt
4569                .drain(..)
4570                .map(|row| start_buffer_row + row - start_multibuffer_row);
4571            let buffer_indents = region
4572                .buffer
4573                .suggested_indents(buffer_rows, single_indent_size);
4574            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4575                (
4576                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4577                    indent,
4578                )
4579            });
4580            result.extend(multibuffer_indents);
4581        }
4582
4583        result
4584    }
4585
4586    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4587        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4588            let mut size = buffer.indent_size_for_line(range.start.row);
4589            size.len = size
4590                .len
4591                .min(range.end.column)
4592                .saturating_sub(range.start.column);
4593            size
4594        } else {
4595            IndentSize::spaces(0)
4596        }
4597    }
4598
4599    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4600        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4601            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4602        } else {
4603            LineIndent::spaces(0)
4604        }
4605    }
4606
4607    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4608        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4609
4610        if self.language_settings(cx).extend_comment_on_newline
4611            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4612        {
4613            let delimiters = language_scope.line_comment_prefixes();
4614            for delimiter in delimiters {
4615                if *self
4616                    .chars_at(Point::new(row.0, indent.len() as u32))
4617                    .take(delimiter.chars().count())
4618                    .collect::<String>()
4619                    .as_str()
4620                    == **delimiter
4621                {
4622                    indent.push_str(delimiter);
4623                    break;
4624                }
4625            }
4626        }
4627
4628        indent
4629    }
4630
4631    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4632    where
4633        T: ToOffset,
4634    {
4635        for char in self.reversed_chars_at(position) {
4636            if !char.is_whitespace() {
4637                return false;
4638            }
4639            if char == '\n' {
4640                return true;
4641            }
4642        }
4643        true
4644    }
4645
4646    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4647        while row.0 > 0 {
4648            row.0 -= 1;
4649            if !self.is_line_blank(row) {
4650                return Some(row);
4651            }
4652        }
4653        None
4654    }
4655
4656    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4657        if let Some((_, range)) = self.buffer_line_for_row(row) {
4658            range.end.column - range.start.column
4659        } else {
4660            0
4661        }
4662    }
4663
4664    pub fn buffer_line_for_row(
4665        &self,
4666        row: MultiBufferRow,
4667    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4668        let mut cursor = self.cursor::<Point>();
4669        let point = Point::new(row.0, 0);
4670        cursor.seek(&point);
4671        let region = cursor.region()?;
4672        let overshoot = point.min(region.range.end) - region.range.start;
4673        let buffer_point = region.buffer_range.start + overshoot;
4674        if buffer_point.row > region.buffer_range.end.row {
4675            return None;
4676        }
4677        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4678        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4679            .min(region.buffer_range.end);
4680        Some((region.buffer, line_start..line_end))
4681    }
4682
4683    pub fn max_point(&self) -> Point {
4684        self.text_summary().lines
4685    }
4686
4687    pub fn max_row(&self) -> MultiBufferRow {
4688        MultiBufferRow(self.text_summary().lines.row)
4689    }
4690
4691    pub fn text_summary(&self) -> TextSummary {
4692        self.diff_transforms.summary().output
4693    }
4694
4695    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4696    where
4697        D: TextDimension,
4698        O: ToOffset,
4699    {
4700        let range = range.start.to_offset(self)..range.end.to_offset(self);
4701        let mut cursor = self
4702            .diff_transforms
4703            .cursor::<Dimensions<usize, ExcerptOffset>>(&());
4704        cursor.seek(&range.start, Bias::Right);
4705
4706        let Some(first_transform) = cursor.item() else {
4707            return D::from_text_summary(&TextSummary::default());
4708        };
4709
4710        let diff_transform_start = cursor.start().0;
4711        let diff_transform_end = cursor.end().0;
4712        let diff_start = range.start;
4713        let start_overshoot = diff_start - diff_transform_start;
4714        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4715
4716        let mut result = match first_transform {
4717            DiffTransform::BufferContent { .. } => {
4718                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4719                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4720                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4721            }
4722            DiffTransform::DeletedHunk {
4723                buffer_id,
4724                base_text_byte_range,
4725                has_trailing_newline,
4726                ..
4727            } => {
4728                let buffer_start = base_text_byte_range.start + start_overshoot;
4729                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4730                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4731                    panic!("{:?} is in non-existent deleted hunk", range.start)
4732                };
4733
4734                let include_trailing_newline =
4735                    *has_trailing_newline && range.end >= diff_transform_end;
4736                if include_trailing_newline {
4737                    buffer_end -= 1;
4738                }
4739
4740                let mut summary =
4741                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4742
4743                if include_trailing_newline {
4744                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4745                }
4746
4747                summary
4748            }
4749        };
4750        if range.end < diff_transform_end {
4751            return result;
4752        }
4753
4754        cursor.next();
4755        result.add_assign(&D::from_text_summary(
4756            &cursor.summary(&range.end, Bias::Right),
4757        ));
4758
4759        let Some(last_transform) = cursor.item() else {
4760            return result;
4761        };
4762
4763        let overshoot = range.end - cursor.start().0;
4764        let suffix = match last_transform {
4765            DiffTransform::BufferContent { .. } => {
4766                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4767                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4768            }
4769            DiffTransform::DeletedHunk {
4770                base_text_byte_range,
4771                buffer_id,
4772                has_trailing_newline,
4773                ..
4774            } => {
4775                let buffer_end = base_text_byte_range.start + overshoot;
4776                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4777                    panic!("{:?} is in non-existent deleted hunk", range.end)
4778                };
4779
4780                let mut suffix = base_text
4781                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4782                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4783                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4784                }
4785                suffix
4786            }
4787        };
4788
4789        result.add_assign(&suffix);
4790        result
4791    }
4792
4793    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4794    where
4795        D: TextDimension,
4796    {
4797        // let mut range = range.start..range.end;
4798        let mut summary = D::zero(&());
4799        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4800        cursor.seek(&range.start, Bias::Right);
4801        if let Some(excerpt) = cursor.item() {
4802            let mut end_before_newline = cursor.end();
4803            if excerpt.has_trailing_newline {
4804                end_before_newline -= ExcerptOffset::new(1);
4805            }
4806
4807            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4808            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4809            let end_in_excerpt =
4810                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4811            summary.add_assign(
4812                &excerpt
4813                    .buffer
4814                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4815            );
4816
4817            if range.end > end_before_newline {
4818                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4819            }
4820
4821            cursor.next();
4822        }
4823
4824        if range.end > *cursor.start() {
4825            summary.add_assign(
4826                &cursor
4827                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4828                    .0,
4829            );
4830            if let Some(excerpt) = cursor.item() {
4831                range.end = cmp::max(*cursor.start(), range.end);
4832
4833                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4834                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4835                summary.add_assign(
4836                    &excerpt
4837                        .buffer
4838                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4839                );
4840            }
4841        }
4842
4843        summary
4844    }
4845
4846    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4847    where
4848        D: TextDimension + Ord + Sub<D, Output = D>,
4849    {
4850        self.summaries_for_anchors([anchor])[0]
4851    }
4852
4853    fn resolve_summary_for_anchor<D>(
4854        &self,
4855        anchor: &Anchor,
4856        excerpt_position: D,
4857        diff_transforms: &mut Cursor<
4858            DiffTransform,
4859            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4860        >,
4861    ) -> D
4862    where
4863        D: TextDimension + Ord + Sub<D, Output = D>,
4864    {
4865        loop {
4866            let transform_end_position = diff_transforms.end().0.0;
4867            let at_transform_end =
4868                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4869            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4870                diff_transforms.next();
4871                continue;
4872            }
4873
4874            let mut position = diff_transforms.start().1.0;
4875            match diff_transforms.item() {
4876                Some(DiffTransform::DeletedHunk {
4877                    buffer_id,
4878                    base_text_byte_range,
4879                    ..
4880                }) => {
4881                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4882                        && let Some(base_text) =
4883                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4884                        && base_text.can_resolve(diff_base_anchor)
4885                    {
4886                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4887                        if base_text_offset >= base_text_byte_range.start
4888                            && base_text_offset <= base_text_byte_range.end
4889                        {
4890                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4891                                base_text_byte_range.start..base_text_offset,
4892                            );
4893                            position.add_assign(&position_in_hunk);
4894                        } else if at_transform_end {
4895                            diff_transforms.next();
4896                            continue;
4897                        }
4898                    }
4899                }
4900                _ => {
4901                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4902                        diff_transforms.next();
4903                        continue;
4904                    }
4905                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4906                    position.add_assign(&overshoot);
4907                }
4908            }
4909
4910            return position;
4911        }
4912    }
4913
4914    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4915        let mut cursor = self
4916            .excerpts
4917            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
4918        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4919
4920        cursor.seek(&Some(locator), Bias::Left);
4921        if cursor.item().is_none() {
4922            cursor.next();
4923        }
4924
4925        let mut position = cursor.start().1;
4926        if let Some(excerpt) = cursor.item()
4927            && excerpt.id == anchor.excerpt_id
4928        {
4929            let excerpt_buffer_start = excerpt
4930                .buffer
4931                .offset_for_anchor(&excerpt.range.context.start);
4932            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4933            let buffer_position = cmp::min(
4934                excerpt_buffer_end,
4935                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4936            );
4937            if buffer_position > excerpt_buffer_start {
4938                position.value += buffer_position - excerpt_buffer_start;
4939            }
4940        }
4941        position
4942    }
4943
4944    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4945        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4946            excerpt_id = *replacement;
4947        }
4948        excerpt_id
4949    }
4950
4951    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4952    where
4953        D: TextDimension + Ord + Sub<D, Output = D>,
4954        I: 'a + IntoIterator<Item = &'a Anchor>,
4955    {
4956        let mut anchors = anchors.into_iter().peekable();
4957        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4958        let mut diff_transforms_cursor = self
4959            .diff_transforms
4960            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(&());
4961        diff_transforms_cursor.next();
4962
4963        let mut summaries = Vec::new();
4964        while let Some(anchor) = anchors.peek() {
4965            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4966            let excerpt_anchors = iter::from_fn(|| {
4967                let anchor = anchors.peek()?;
4968                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4969                    Some(anchors.next().unwrap())
4970                } else {
4971                    None
4972                }
4973            });
4974
4975            let locator = self.excerpt_locator_for_id(excerpt_id);
4976            cursor.seek_forward(locator, Bias::Left);
4977            if cursor.item().is_none() {
4978                cursor.next();
4979            }
4980
4981            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4982            if let Some(excerpt) = cursor.item() {
4983                if excerpt.id != excerpt_id {
4984                    let position = self.resolve_summary_for_anchor(
4985                        &Anchor::min(),
4986                        excerpt_start_position,
4987                        &mut diff_transforms_cursor,
4988                    );
4989                    summaries.extend(excerpt_anchors.map(|_| position));
4990                    continue;
4991                }
4992                let excerpt_buffer_start =
4993                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4994                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4995                for (buffer_summary, anchor) in excerpt
4996                    .buffer
4997                    .summaries_for_anchors_with_payload::<D, _, _>(
4998                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4999                    )
5000                {
5001                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5002                    let mut position = excerpt_start_position;
5003                    if summary > excerpt_buffer_start {
5004                        position.add_assign(&(summary - excerpt_buffer_start));
5005                    }
5006
5007                    if position > diff_transforms_cursor.start().0.0 {
5008                        diff_transforms_cursor
5009                            .seek_forward(&ExcerptDimension(position), Bias::Left);
5010                    }
5011
5012                    summaries.push(self.resolve_summary_for_anchor(
5013                        anchor,
5014                        position,
5015                        &mut diff_transforms_cursor,
5016                    ));
5017                }
5018            } else {
5019                diff_transforms_cursor
5020                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
5021                let position = self.resolve_summary_for_anchor(
5022                    &Anchor::max(),
5023                    excerpt_start_position,
5024                    &mut diff_transforms_cursor,
5025                );
5026                summaries.extend(excerpt_anchors.map(|_| position));
5027            }
5028        }
5029
5030        summaries
5031    }
5032
5033    pub fn dimensions_from_points<'a, D>(
5034        &'a self,
5035        points: impl 'a + IntoIterator<Item = Point>,
5036    ) -> impl 'a + Iterator<Item = D>
5037    where
5038        D: TextDimension + Sub<D, Output = D>,
5039    {
5040        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
5041        cursor.seek(&DimensionPair {
5042            key: Point::default(),
5043            value: None,
5044        });
5045        let mut points = points.into_iter();
5046        iter::from_fn(move || {
5047            let point = points.next()?;
5048
5049            cursor.seek_forward(&DimensionPair {
5050                key: point,
5051                value: None,
5052            });
5053
5054            if let Some(region) = cursor.region() {
5055                let overshoot = point - region.range.start.key;
5056                let buffer_point = region.buffer_range.start.key + overshoot;
5057                let mut position = region.range.start.value.unwrap();
5058                position.add_assign(
5059                    &region
5060                        .buffer
5061                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
5062                );
5063                if point == region.range.end.key && region.has_trailing_newline {
5064                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
5065                }
5066                Some(position)
5067            } else {
5068                Some(D::from_text_summary(&self.text_summary()))
5069            }
5070        })
5071    }
5072
5073    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5074    where
5075        I: 'a + IntoIterator<Item = &'a Anchor>,
5076    {
5077        let mut anchors = anchors.into_iter().enumerate().peekable();
5078        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5079        cursor.next();
5080
5081        let mut result = Vec::new();
5082
5083        while let Some((_, anchor)) = anchors.peek() {
5084            let old_excerpt_id = anchor.excerpt_id;
5085
5086            // Find the location where this anchor's excerpt should be.
5087            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5088            cursor.seek_forward(&Some(old_locator), Bias::Left);
5089
5090            if cursor.item().is_none() {
5091                cursor.next();
5092            }
5093
5094            let next_excerpt = cursor.item();
5095            let prev_excerpt = cursor.prev_item();
5096
5097            // Process all of the anchors for this excerpt.
5098            while let Some((_, anchor)) = anchors.peek() {
5099                if anchor.excerpt_id != old_excerpt_id {
5100                    break;
5101                }
5102                let (anchor_ix, anchor) = anchors.next().unwrap();
5103                let mut anchor = *anchor;
5104
5105                // Leave min and max anchors unchanged if invalid or
5106                // if the old excerpt still exists at this location
5107                let mut kept_position = next_excerpt
5108                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5109                    || old_excerpt_id == ExcerptId::max()
5110                    || old_excerpt_id == ExcerptId::min();
5111
5112                // If the old excerpt no longer exists at this location, then attempt to
5113                // find an equivalent position for this anchor in an adjacent excerpt.
5114                if !kept_position {
5115                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5116                        if excerpt.contains(&anchor) {
5117                            anchor.excerpt_id = excerpt.id;
5118                            kept_position = true;
5119                            break;
5120                        }
5121                    }
5122                }
5123
5124                // If there's no adjacent excerpt that contains the anchor's position,
5125                // then report that the anchor has lost its position.
5126                if !kept_position {
5127                    anchor = if let Some(excerpt) = next_excerpt {
5128                        let mut text_anchor = excerpt
5129                            .range
5130                            .context
5131                            .start
5132                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5133                        if text_anchor
5134                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5135                            .is_gt()
5136                        {
5137                            text_anchor = excerpt.range.context.end;
5138                        }
5139                        Anchor {
5140                            buffer_id: Some(excerpt.buffer_id),
5141                            excerpt_id: excerpt.id,
5142                            text_anchor,
5143                            diff_base_anchor: None,
5144                        }
5145                    } else if let Some(excerpt) = prev_excerpt {
5146                        let mut text_anchor = excerpt
5147                            .range
5148                            .context
5149                            .end
5150                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5151                        if text_anchor
5152                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5153                            .is_lt()
5154                        {
5155                            text_anchor = excerpt.range.context.start;
5156                        }
5157                        Anchor {
5158                            buffer_id: Some(excerpt.buffer_id),
5159                            excerpt_id: excerpt.id,
5160                            text_anchor,
5161                            diff_base_anchor: None,
5162                        }
5163                    } else if anchor.text_anchor.bias == Bias::Left {
5164                        Anchor::min()
5165                    } else {
5166                        Anchor::max()
5167                    };
5168                }
5169
5170                result.push((anchor_ix, anchor, kept_position));
5171            }
5172        }
5173        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5174        result
5175    }
5176
5177    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5178        self.anchor_at(position, Bias::Left)
5179    }
5180
5181    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5182        self.anchor_at(position, Bias::Right)
5183    }
5184
5185    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5186        let offset = position.to_offset(self);
5187
5188        // Find the given position in the diff transforms. Determine the corresponding
5189        // offset in the excerpts, and whether the position is within a deleted hunk.
5190        let mut diff_transforms = self
5191            .diff_transforms
5192            .cursor::<Dimensions<usize, ExcerptOffset>>(&());
5193        diff_transforms.seek(&offset, Bias::Right);
5194
5195        if offset == diff_transforms.start().0
5196            && bias == Bias::Left
5197            && let Some(prev_item) = diff_transforms.prev_item()
5198            && let DiffTransform::DeletedHunk { .. } = prev_item
5199        {
5200            diff_transforms.prev();
5201        }
5202        let offset_in_transform = offset - diff_transforms.start().0;
5203        let mut excerpt_offset = diff_transforms.start().1;
5204        let mut diff_base_anchor = None;
5205        if let Some(DiffTransform::DeletedHunk {
5206            buffer_id,
5207            base_text_byte_range,
5208            has_trailing_newline,
5209            ..
5210        }) = diff_transforms.item()
5211        {
5212            let diff = self.diffs.get(buffer_id).expect("missing diff");
5213            if offset_in_transform > base_text_byte_range.len() {
5214                debug_assert!(*has_trailing_newline);
5215                bias = Bias::Right;
5216            } else {
5217                diff_base_anchor = Some(
5218                    diff.base_text()
5219                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5220                );
5221                bias = Bias::Left;
5222            }
5223        } else {
5224            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5225        };
5226
5227        let mut excerpts = self
5228            .excerpts
5229            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(&());
5230        excerpts.seek(&excerpt_offset, Bias::Right);
5231        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5232            excerpts.prev();
5233        }
5234        if let Some(excerpt) = excerpts.item() {
5235            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5236            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5237                overshoot -= 1;
5238                bias = Bias::Right;
5239            }
5240
5241            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5242            let text_anchor =
5243                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5244            Anchor {
5245                buffer_id: Some(excerpt.buffer_id),
5246                excerpt_id: excerpt.id,
5247                text_anchor,
5248                diff_base_anchor,
5249            }
5250        } else {
5251            let mut anchor = if excerpt_offset.is_zero() && bias == Bias::Left {
5252                Anchor::min()
5253            } else {
5254                Anchor::max()
5255            };
5256            // TODO this is a hack, remove it
5257            if let Some((excerpt_id, _, _)) = self.as_singleton() {
5258                anchor.excerpt_id = *excerpt_id;
5259            }
5260            anchor
5261        }
5262    }
5263
5264    /// Returns an anchor for the given excerpt and text anchor,
5265    /// returns None if the excerpt_id is no longer valid.
5266    pub fn anchor_in_excerpt(
5267        &self,
5268        excerpt_id: ExcerptId,
5269        text_anchor: text::Anchor,
5270    ) -> Option<Anchor> {
5271        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5272        let locator = self.excerpt_locator_for_id(excerpt_id);
5273        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5274        cursor.seek(locator, Bias::Left);
5275        if let Some(excerpt) = cursor.item()
5276            && excerpt.id == excerpt_id
5277        {
5278            let text_anchor = excerpt.clip_anchor(text_anchor);
5279            drop(cursor);
5280            return Some(Anchor {
5281                buffer_id: Some(excerpt.buffer_id),
5282                excerpt_id,
5283                text_anchor,
5284                diff_base_anchor: None,
5285            });
5286        }
5287        None
5288    }
5289
5290    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5291        Some(self.excerpt(excerpt_id)?.range.context.clone())
5292    }
5293
5294    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5295        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5296            true
5297        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5298            excerpt.buffer.can_resolve(&anchor.text_anchor)
5299        } else {
5300            false
5301        }
5302    }
5303
5304    pub fn excerpts(
5305        &self,
5306    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5307        self.excerpts
5308            .iter()
5309            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5310    }
5311
5312    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
5313        let excerpts = self.excerpts.cursor(&());
5314        let diff_transforms = self.diff_transforms.cursor(&());
5315        MultiBufferCursor {
5316            excerpts,
5317            diff_transforms,
5318            diffs: &self.diffs,
5319            cached_region: None,
5320        }
5321    }
5322
5323    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5324        let start_locator = self.excerpt_locator_for_id(id);
5325        let mut excerpts = self
5326            .excerpts
5327            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(&());
5328        excerpts.seek(&Some(start_locator), Bias::Left);
5329        excerpts.prev();
5330
5331        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(&());
5332        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5333        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5334            diff_transforms.next();
5335        }
5336
5337        let excerpt = excerpts.item()?;
5338        Some(MultiBufferExcerpt {
5339            excerpt,
5340            offset: diff_transforms.start().output_dimension.0,
5341            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5342            excerpt_offset: excerpts.start().1.clone(),
5343            diff_transforms,
5344        })
5345    }
5346
5347    pub fn excerpt_boundaries_in_range<R, T>(
5348        &self,
5349        range: R,
5350    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5351    where
5352        R: RangeBounds<T>,
5353        T: ToOffset,
5354    {
5355        let start_offset;
5356        let start = match range.start_bound() {
5357            Bound::Included(start) => {
5358                start_offset = start.to_offset(self);
5359                Bound::Included(start_offset)
5360            }
5361            Bound::Excluded(_) => {
5362                panic!("not supported")
5363            }
5364            Bound::Unbounded => {
5365                start_offset = 0;
5366                Bound::Unbounded
5367            }
5368        };
5369        let end = match range.end_bound() {
5370            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5371            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5372            Bound::Unbounded => Bound::Unbounded,
5373        };
5374        let bounds = (start, end);
5375
5376        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5377        cursor.seek(&DimensionPair {
5378            key: start_offset,
5379            value: None,
5380        });
5381
5382        if cursor
5383            .region()
5384            .is_some_and(|region| bounds.contains(&region.range.start.key))
5385        {
5386            cursor.prev_excerpt();
5387        } else {
5388            cursor.seek_to_start_of_current_excerpt();
5389        }
5390        let mut prev_region = cursor.region();
5391
5392        cursor.next_excerpt();
5393
5394        iter::from_fn(move || {
5395            loop {
5396                if self.singleton {
5397                    return None;
5398                }
5399
5400                let next_region = cursor.region()?;
5401                cursor.next_excerpt();
5402                if !bounds.contains(&next_region.range.start.key) {
5403                    prev_region = Some(next_region);
5404                    continue;
5405                }
5406
5407                let next_region_start = next_region.range.start.value.unwrap();
5408                let next_region_end = if let Some(region) = cursor.region() {
5409                    region.range.start.value.unwrap()
5410                } else {
5411                    self.max_point()
5412                };
5413
5414                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5415                    id: region.excerpt.id,
5416                    buffer: region.excerpt.buffer.clone(),
5417                    buffer_id: region.excerpt.buffer_id,
5418                    range: region.excerpt.range.clone(),
5419                    end_row: MultiBufferRow(next_region_start.row),
5420                });
5421
5422                let next = ExcerptInfo {
5423                    id: next_region.excerpt.id,
5424                    buffer: next_region.excerpt.buffer.clone(),
5425                    buffer_id: next_region.excerpt.buffer_id,
5426                    range: next_region.excerpt.range.clone(),
5427                    end_row: if next_region.excerpt.has_trailing_newline {
5428                        MultiBufferRow(next_region_end.row - 1)
5429                    } else {
5430                        MultiBufferRow(next_region_end.row)
5431                    },
5432                };
5433
5434                let row = MultiBufferRow(next_region_start.row);
5435
5436                prev_region = Some(next_region);
5437
5438                return Some(ExcerptBoundary { row, prev, next });
5439            }
5440        })
5441    }
5442
5443    pub fn edit_count(&self) -> usize {
5444        self.edit_count
5445    }
5446
5447    pub fn non_text_state_update_count(&self) -> usize {
5448        self.non_text_state_update_count
5449    }
5450
5451    /// Returns the smallest enclosing bracket ranges containing the given range or
5452    /// None if no brackets contain range or the range is not contained in a single
5453    /// excerpt
5454    ///
5455    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5456    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5457        &self,
5458        range: Range<T>,
5459        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5460    ) -> Option<(Range<usize>, Range<usize>)> {
5461        let range = range.start.to_offset(self)..range.end.to_offset(self);
5462        let mut excerpt = self.excerpt_containing(range.clone())?;
5463        let buffer = excerpt.buffer();
5464        let excerpt_buffer_range = excerpt.buffer_range();
5465
5466        // Filter to ranges contained in the excerpt
5467        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5468            excerpt_buffer_range.contains(&open.start)
5469                && excerpt_buffer_range.contains(&close.end)
5470                && range_filter.is_none_or(|filter| filter(buffer, open, close))
5471        };
5472
5473        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5474            excerpt.map_range_to_buffer(range),
5475            Some(&range_filter),
5476        )?;
5477
5478        Some((
5479            excerpt.map_range_from_buffer(open),
5480            excerpt.map_range_from_buffer(close),
5481        ))
5482    }
5483
5484    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5485    /// not contained in a single excerpt
5486    pub fn enclosing_bracket_ranges<T: ToOffset>(
5487        &self,
5488        range: Range<T>,
5489    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5490        let range = range.start.to_offset(self)..range.end.to_offset(self);
5491        let mut excerpt = self.excerpt_containing(range.clone())?;
5492
5493        Some(
5494            excerpt
5495                .buffer()
5496                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5497                .filter_map(move |pair| {
5498                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5499                        Some((
5500                            excerpt.map_range_from_buffer(pair.open_range),
5501                            excerpt.map_range_from_buffer(pair.close_range),
5502                        ))
5503                    } else {
5504                        None
5505                    }
5506                }),
5507        )
5508    }
5509
5510    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5511    /// not contained in a single excerpt
5512    pub fn text_object_ranges<T: ToOffset>(
5513        &self,
5514        range: Range<T>,
5515        options: TreeSitterOptions,
5516    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5517        let range = range.start.to_offset(self)..range.end.to_offset(self);
5518        self.excerpt_containing(range.clone())
5519            .map(|mut excerpt| {
5520                excerpt
5521                    .buffer()
5522                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5523                    .filter_map(move |(range, text_object)| {
5524                        if excerpt.contains_buffer_range(range.clone()) {
5525                            Some((excerpt.map_range_from_buffer(range), text_object))
5526                        } else {
5527                            None
5528                        }
5529                    })
5530            })
5531            .into_iter()
5532            .flatten()
5533    }
5534
5535    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5536    /// not contained in a single excerpt
5537    pub fn bracket_ranges<T: ToOffset>(
5538        &self,
5539        range: Range<T>,
5540    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5541        let range = range.start.to_offset(self)..range.end.to_offset(self);
5542        let mut excerpt = self.excerpt_containing(range.clone())?;
5543
5544        Some(
5545            excerpt
5546                .buffer()
5547                .bracket_ranges(excerpt.map_range_to_buffer(range))
5548                .filter_map(move |pair| {
5549                    let buffer_range = pair.open_range.start..pair.close_range.end;
5550                    if excerpt.contains_buffer_range(buffer_range) {
5551                        Some((
5552                            excerpt.map_range_from_buffer(pair.open_range),
5553                            excerpt.map_range_from_buffer(pair.close_range),
5554                        ))
5555                    } else {
5556                        None
5557                    }
5558                }),
5559        )
5560    }
5561
5562    pub fn redacted_ranges<'a, T: ToOffset>(
5563        &'a self,
5564        range: Range<T>,
5565        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5566    ) -> impl Iterator<Item = Range<usize>> + 'a {
5567        let range = range.start.to_offset(self)..range.end.to_offset(self);
5568        self.lift_buffer_metadata(range, move |buffer, range| {
5569            if redaction_enabled(buffer.file()) {
5570                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5571            } else {
5572                None
5573            }
5574        })
5575        .map(|(range, _, _)| range)
5576    }
5577
5578    pub fn runnable_ranges(
5579        &self,
5580        range: Range<Anchor>,
5581    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5582        let range = range.start.to_offset(self)..range.end.to_offset(self);
5583        self.lift_buffer_metadata(range, move |buffer, range| {
5584            Some(
5585                buffer
5586                    .runnable_ranges(range.clone())
5587                    .filter(move |runnable| {
5588                        runnable.run_range.start >= range.start
5589                            && runnable.run_range.end < range.end
5590                    })
5591                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5592            )
5593        })
5594        .map(|(run_range, runnable, _)| language::RunnableRange {
5595            run_range,
5596            ..runnable
5597        })
5598    }
5599
5600    pub fn line_indents(
5601        &self,
5602        start_row: MultiBufferRow,
5603        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5604    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5605        let max_point = self.max_point();
5606        let mut cursor = self.cursor::<Point>();
5607        cursor.seek(&Point::new(start_row.0, 0));
5608        iter::from_fn(move || {
5609            let mut region = cursor.region()?;
5610            while !buffer_filter(&region.excerpt.buffer) {
5611                cursor.next();
5612                region = cursor.region()?;
5613            }
5614            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5615            let buffer_start_row =
5616                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5617
5618            let buffer_end_row = if region.is_main_buffer
5619                && (region.has_trailing_newline || region.range.end == max_point)
5620            {
5621                region.buffer_range.end.row
5622            } else {
5623                region.buffer_range.end.row.saturating_sub(1)
5624            };
5625
5626            let line_indents = region
5627                .buffer
5628                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5629            cursor.next();
5630            Some(line_indents.map(move |(buffer_row, indent)| {
5631                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5632                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5633            }))
5634        })
5635        .flatten()
5636    }
5637
5638    pub fn reversed_line_indents(
5639        &self,
5640        end_row: MultiBufferRow,
5641        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5642    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5643        let max_point = self.max_point();
5644        let mut cursor = self.cursor::<Point>();
5645        cursor.seek(&Point::new(end_row.0, 0));
5646        iter::from_fn(move || {
5647            let mut region = cursor.region()?;
5648            while !buffer_filter(&region.excerpt.buffer) {
5649                cursor.prev();
5650                region = cursor.region()?;
5651            }
5652
5653            let buffer_start_row = region.buffer_range.start.row;
5654            let buffer_end_row = if region.is_main_buffer
5655                && (region.has_trailing_newline || region.range.end == max_point)
5656            {
5657                region.buffer_range.end.row + 1
5658            } else {
5659                region.buffer_range.end.row
5660            };
5661
5662            let overshoot = end_row.0 - region.range.start.row;
5663            let buffer_end_row =
5664                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5665
5666            let line_indents = region
5667                .buffer
5668                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5669            cursor.prev();
5670            Some(line_indents.map(move |(buffer_row, indent)| {
5671                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5672                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5673            }))
5674        })
5675        .flatten()
5676    }
5677
5678    pub async fn enclosing_indent(
5679        &self,
5680        mut target_row: MultiBufferRow,
5681    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5682        let max_row = MultiBufferRow(self.max_point().row);
5683        if target_row >= max_row {
5684            return None;
5685        }
5686
5687        let mut target_indent = self.line_indent_for_row(target_row);
5688
5689        // If the current row is at the start of an indented block, we want to return this
5690        // block as the enclosing indent.
5691        if !target_indent.is_line_empty() && target_row < max_row {
5692            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5693            if !next_line_indent.is_line_empty()
5694                && target_indent.raw_len() < next_line_indent.raw_len()
5695            {
5696                target_indent = next_line_indent;
5697                target_row.0 += 1;
5698            }
5699        }
5700
5701        const SEARCH_ROW_LIMIT: u32 = 25000;
5702        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5703        const YIELD_INTERVAL: u32 = 100;
5704
5705        let mut accessed_row_counter = 0;
5706
5707        // If there is a blank line at the current row, search for the next non indented lines
5708        if target_indent.is_line_empty() {
5709            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5710            let end =
5711                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5712
5713            let mut non_empty_line_above = None;
5714            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5715                if row < start {
5716                    break;
5717                }
5718                accessed_row_counter += 1;
5719                if accessed_row_counter == YIELD_INTERVAL {
5720                    accessed_row_counter = 0;
5721                    yield_now().await;
5722                }
5723                if !indent.is_line_empty() {
5724                    non_empty_line_above = Some((row, indent));
5725                    break;
5726                }
5727            }
5728
5729            let mut non_empty_line_below = None;
5730            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5731                if row > end {
5732                    break;
5733                }
5734                accessed_row_counter += 1;
5735                if accessed_row_counter == YIELD_INTERVAL {
5736                    accessed_row_counter = 0;
5737                    yield_now().await;
5738                }
5739                if !indent.is_line_empty() {
5740                    non_empty_line_below = Some((row, indent));
5741                    break;
5742                }
5743            }
5744
5745            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5746                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5747                    if above_indent.raw_len() >= below_indent.raw_len() {
5748                        (above_row, above_indent)
5749                    } else {
5750                        (below_row, below_indent)
5751                    }
5752                }
5753                (Some(above), None) => above,
5754                (None, Some(below)) => below,
5755                _ => return None,
5756            };
5757
5758            target_indent = indent;
5759            target_row = row;
5760        }
5761
5762        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5763        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5764
5765        let mut start_indent = None;
5766        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5767            if row < start {
5768                break;
5769            }
5770            accessed_row_counter += 1;
5771            if accessed_row_counter == YIELD_INTERVAL {
5772                accessed_row_counter = 0;
5773                yield_now().await;
5774            }
5775            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5776                start_indent = Some((row, indent));
5777                break;
5778            }
5779        }
5780        let (start_row, start_indent_size) = start_indent?;
5781
5782        let mut end_indent = (end, None);
5783        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5784            if row > end {
5785                break;
5786            }
5787            accessed_row_counter += 1;
5788            if accessed_row_counter == YIELD_INTERVAL {
5789                accessed_row_counter = 0;
5790                yield_now().await;
5791            }
5792            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5793                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5794                break;
5795            }
5796        }
5797        let (end_row, end_indent_size) = end_indent;
5798
5799        let indent = if let Some(end_indent_size) = end_indent_size {
5800            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5801                start_indent_size
5802            } else {
5803                end_indent_size
5804            }
5805        } else {
5806            start_indent_size
5807        };
5808
5809        Some((start_row..end_row, indent))
5810    }
5811
5812    pub fn indent_guides_in_range<T: ToPoint>(
5813        &self,
5814        range: Range<T>,
5815        ignore_disabled_for_language: bool,
5816        cx: &App,
5817    ) -> impl Iterator<Item = IndentGuide> {
5818        let range = range.start.to_point(self)..range.end.to_point(self);
5819        let start_row = MultiBufferRow(range.start.row);
5820        let end_row = MultiBufferRow(range.end.row);
5821
5822        let mut row_indents = self.line_indents(start_row, |buffer| {
5823            let settings =
5824                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5825            settings.indent_guides.enabled || ignore_disabled_for_language
5826        });
5827
5828        let mut result = Vec::new();
5829        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5830
5831        let mut prev_settings = None;
5832        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5833            if first_row > end_row {
5834                break;
5835            }
5836            let current_depth = indent_stack.len() as u32;
5837
5838            // Avoid retrieving the language settings repeatedly for every buffer row.
5839            if let Some((prev_buffer_id, _)) = &prev_settings
5840                && prev_buffer_id != &buffer.remote_id()
5841            {
5842                prev_settings.take();
5843            }
5844            let settings = &prev_settings
5845                .get_or_insert_with(|| {
5846                    (
5847                        buffer.remote_id(),
5848                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5849                    )
5850                })
5851                .1;
5852            let tab_size = settings.tab_size.get();
5853
5854            // When encountering empty, continue until found useful line indent
5855            // then add to the indent stack with the depth found
5856            let mut found_indent = false;
5857            let mut last_row = first_row;
5858            if line_indent.is_line_blank() {
5859                while !found_indent {
5860                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5861                        break;
5862                    };
5863                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5864                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5865                        break;
5866                    }
5867
5868                    if new_line_indent.is_line_blank() {
5869                        continue;
5870                    }
5871                    last_row = target_row.min(end_row);
5872                    line_indent = new_line_indent;
5873                    found_indent = true;
5874                    break;
5875                }
5876            } else {
5877                found_indent = true
5878            }
5879
5880            let depth = if found_indent {
5881                line_indent.len(tab_size) / tab_size
5882            } else {
5883                0
5884            };
5885
5886            match depth.cmp(&current_depth) {
5887                cmp::Ordering::Less => {
5888                    for _ in 0..(current_depth - depth) {
5889                        let mut indent = indent_stack.pop().unwrap();
5890                        if last_row != first_row {
5891                            // In this case, we landed on an empty row, had to seek forward,
5892                            // and discovered that the indent we where on is ending.
5893                            // This means that the last display row must
5894                            // be on line that ends this indent range, so we
5895                            // should display the range up to the first non-empty line
5896                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5897                        }
5898
5899                        result.push(indent)
5900                    }
5901                }
5902                cmp::Ordering::Greater => {
5903                    for next_depth in current_depth..depth {
5904                        indent_stack.push(IndentGuide {
5905                            buffer_id: buffer.remote_id(),
5906                            start_row: first_row,
5907                            end_row: last_row,
5908                            depth: next_depth,
5909                            tab_size,
5910                            settings: settings.indent_guides,
5911                        });
5912                    }
5913                }
5914                _ => {}
5915            }
5916
5917            for indent in indent_stack.iter_mut() {
5918                indent.end_row = last_row;
5919            }
5920        }
5921
5922        result.extend(indent_stack);
5923        result.into_iter()
5924    }
5925
5926    pub fn trailing_excerpt_update_count(&self) -> usize {
5927        self.trailing_excerpt_update_count
5928    }
5929
5930    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5931        self.point_to_buffer_offset(point)
5932            .and_then(|(buffer, _)| buffer.file())
5933    }
5934
5935    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5936        self.point_to_buffer_offset(point)
5937            .and_then(|(buffer, offset)| buffer.language_at(offset))
5938    }
5939
5940    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5941        self.excerpts
5942            .first()
5943            .map(|excerpt| &excerpt.buffer)
5944            .map(|buffer| {
5945                language_settings(
5946                    buffer.language().map(|language| language.name()),
5947                    buffer.file(),
5948                    cx,
5949                )
5950            })
5951            .unwrap_or_else(move || self.language_settings_at(0, cx))
5952    }
5953
5954    pub fn language_settings_at<'a, T: ToOffset>(
5955        &'a self,
5956        point: T,
5957        cx: &'a App,
5958    ) -> Cow<'a, LanguageSettings> {
5959        let mut language = None;
5960        let mut file = None;
5961        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5962            language = buffer.language_at(offset);
5963            file = buffer.file();
5964        }
5965        language_settings(language.map(|l| l.name()), file, cx)
5966    }
5967
5968    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5969        self.point_to_buffer_offset(point)
5970            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5971    }
5972
5973    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5974        self.point_to_buffer_offset(point)
5975            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5976            .unwrap_or_default()
5977    }
5978
5979    pub fn language_indent_size_at<T: ToOffset>(
5980        &self,
5981        position: T,
5982        cx: &App,
5983    ) -> Option<IndentSize> {
5984        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5985        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5986    }
5987
5988    pub fn is_dirty(&self) -> bool {
5989        self.is_dirty
5990    }
5991
5992    pub fn has_deleted_file(&self) -> bool {
5993        self.has_deleted_file
5994    }
5995
5996    pub fn has_conflict(&self) -> bool {
5997        self.has_conflict
5998    }
5999
6000    pub fn has_diagnostics(&self) -> bool {
6001        self.excerpts
6002            .iter()
6003            .any(|excerpt| excerpt.buffer.has_diagnostics())
6004    }
6005
6006    pub fn diagnostic_group(
6007        &self,
6008        buffer_id: BufferId,
6009        group_id: usize,
6010    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
6011        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
6012            if buffer.remote_id() != buffer_id {
6013                return None;
6014            };
6015            Some(
6016                buffer
6017                    .diagnostics_in_range(range, false)
6018                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6019                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
6020            )
6021        })
6022        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6023    }
6024
6025    pub fn diagnostics_in_range<'a, T>(
6026        &'a self,
6027        range: Range<T>,
6028    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
6029    where
6030        T: 'a
6031            + text::ToOffset
6032            + text::FromAnchor
6033            + TextDimension
6034            + Ord
6035            + Sub<T, Output = T>
6036            + fmt::Debug,
6037    {
6038        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6039            Some(
6040                buffer
6041                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6042                    .map(|entry| (entry.range, entry.diagnostic)),
6043            )
6044        })
6045        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6046    }
6047
6048    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
6049        &'a self,
6050        range: Range<T>,
6051    ) -> impl Iterator<Item = (BufferId, DiagnosticEntry<T>)> + 'a
6052    where
6053        T: 'a
6054            + text::ToOffset
6055            + text::FromAnchor
6056            + TextDimension
6057            + Ord
6058            + Sub<T, Output = T>
6059            + fmt::Debug,
6060    {
6061        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6062            Some(
6063                buffer
6064                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6065                    .map(|entry| (entry.range, entry.diagnostic)),
6066            )
6067        })
6068        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntry { diagnostic, range }))
6069    }
6070
6071    pub fn syntax_ancestor<T: ToOffset>(
6072        &self,
6073        range: Range<T>,
6074    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
6075        let range = range.start.to_offset(self)..range.end.to_offset(self);
6076        let mut excerpt = self.excerpt_containing(range.clone())?;
6077        let node = excerpt
6078            .buffer()
6079            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6080        let node_range = node.byte_range();
6081        if !excerpt.contains_buffer_range(node_range.clone()) {
6082            return None;
6083        };
6084        Some((node, excerpt.map_range_from_buffer(node_range)))
6085    }
6086
6087    pub fn syntax_next_sibling<T: ToOffset>(
6088        &self,
6089        range: Range<T>,
6090    ) -> Option<tree_sitter::Node<'_>> {
6091        let range = range.start.to_offset(self)..range.end.to_offset(self);
6092        let mut excerpt = self.excerpt_containing(range.clone())?;
6093        excerpt
6094            .buffer()
6095            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
6096    }
6097
6098    pub fn syntax_prev_sibling<T: ToOffset>(
6099        &self,
6100        range: Range<T>,
6101    ) -> Option<tree_sitter::Node<'_>> {
6102        let range = range.start.to_offset(self)..range.end.to_offset(self);
6103        let mut excerpt = self.excerpt_containing(range.clone())?;
6104        excerpt
6105            .buffer()
6106            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
6107    }
6108
6109    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6110        let (excerpt_id, _, buffer) = self.as_singleton()?;
6111        let outline = buffer.outline(theme);
6112        Some(Outline::new(
6113            outline
6114                .items
6115                .into_iter()
6116                .flat_map(|item| {
6117                    Some(OutlineItem {
6118                        depth: item.depth,
6119                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
6120                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
6121                        text: item.text,
6122                        highlight_ranges: item.highlight_ranges,
6123                        name_ranges: item.name_ranges,
6124                        signature_range: item.signature_range.and_then(|signature_range| {
6125                            Some(
6126                                self.anchor_in_excerpt(*excerpt_id, signature_range.start)?
6127                                    ..self.anchor_in_excerpt(*excerpt_id, signature_range.end)?,
6128                            )
6129                        }),
6130                        body_range: item.body_range.and_then(|body_range| {
6131                            Some(
6132                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
6133                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
6134                            )
6135                        }),
6136                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6137                            Some(
6138                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6139                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6140                            )
6141                        }),
6142                    })
6143                })
6144                .collect(),
6145        ))
6146    }
6147
6148    pub fn symbols_containing<T: ToOffset>(
6149        &self,
6150        offset: T,
6151        theme: Option<&SyntaxTheme>,
6152    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6153        let anchor = self.anchor_before(offset);
6154        let excerpt_id = anchor.excerpt_id;
6155        let excerpt = self.excerpt(excerpt_id)?;
6156        Some((
6157            excerpt.buffer_id,
6158            excerpt
6159                .buffer
6160                .symbols_containing(anchor.text_anchor, theme)
6161                .into_iter()
6162                .flat_map(|item| {
6163                    Some(OutlineItem {
6164                        depth: item.depth,
6165                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6166                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6167                        text: item.text,
6168                        highlight_ranges: item.highlight_ranges,
6169                        name_ranges: item.name_ranges,
6170                        signature_range: item.signature_range.and_then(|signature_range| {
6171                            Some(
6172                                self.anchor_in_excerpt(excerpt_id, signature_range.start)?
6173                                    ..self.anchor_in_excerpt(excerpt_id, signature_range.end)?,
6174                            )
6175                        }),
6176                        body_range: item.body_range.and_then(|body_range| {
6177                            Some(
6178                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6179                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6180                            )
6181                        }),
6182                        annotation_range: item.annotation_range.and_then(|body_range| {
6183                            Some(
6184                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6185                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6186                            )
6187                        }),
6188                    })
6189                })
6190                .collect(),
6191        ))
6192    }
6193
6194    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6195        if id == ExcerptId::min() {
6196            Locator::min_ref()
6197        } else if id == ExcerptId::max() {
6198            Locator::max_ref()
6199        } else {
6200            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6201            cursor.seek(&id, Bias::Left);
6202            if let Some(entry) = cursor.item()
6203                && entry.id == id
6204            {
6205                return &entry.locator;
6206            }
6207            panic!("invalid excerpt id {id:?}")
6208        }
6209    }
6210
6211    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6212    fn excerpt_locators_for_ids(
6213        &self,
6214        ids: impl IntoIterator<Item = ExcerptId>,
6215    ) -> SmallVec<[Locator; 1]> {
6216        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6217        sorted_ids.sort_unstable();
6218        let mut locators = SmallVec::new();
6219
6220        while sorted_ids.last() == Some(&ExcerptId::max()) {
6221            sorted_ids.pop();
6222            if let Some(mapping) = self.excerpt_ids.last() {
6223                locators.push(mapping.locator.clone());
6224            }
6225        }
6226
6227        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6228        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6229            sorted_ids.next();
6230            if let Some(mapping) = self.excerpt_ids.first() {
6231                locators.push(mapping.locator.clone());
6232            }
6233        }
6234
6235        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6236        for id in sorted_ids {
6237            if cursor.seek_forward(&id, Bias::Left) {
6238                locators.push(cursor.item().unwrap().locator.clone());
6239            } else {
6240                panic!("invalid excerpt id {:?}", id);
6241            }
6242        }
6243
6244        locators.sort_unstable();
6245        locators
6246    }
6247
6248    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6249        Some(self.excerpt(excerpt_id)?.buffer_id)
6250    }
6251
6252    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6253        Some(&self.excerpt(excerpt_id)?.buffer)
6254    }
6255
6256    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6257        let mut cursor = self
6258            .excerpts
6259            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(&());
6260        let locator = self.excerpt_locator_for_id(excerpt_id);
6261        if cursor.seek(&Some(locator), Bias::Left) {
6262            let start = cursor.start().1.clone();
6263            let end = cursor.end().1;
6264            let mut diff_transforms = self
6265                .diff_transforms
6266                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(&());
6267            diff_transforms.seek(&start, Bias::Left);
6268            let overshoot = start.0 - diff_transforms.start().0.0;
6269            let start = diff_transforms.start().1.0 + overshoot;
6270            diff_transforms.seek(&end, Bias::Right);
6271            let overshoot = end.0 - diff_transforms.start().0.0;
6272            let end = diff_transforms.start().1.0 + overshoot;
6273            Some(start..end)
6274        } else {
6275            None
6276        }
6277    }
6278
6279    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6280        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6281        let locator = self.excerpt_locator_for_id(excerpt_id);
6282        if cursor.seek(&Some(locator), Bias::Left)
6283            && let Some(excerpt) = cursor.item()
6284        {
6285            return Some(excerpt.range.context.clone());
6286        }
6287        None
6288    }
6289
6290    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6291        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6292        let locator = self.excerpt_locator_for_id(excerpt_id);
6293        cursor.seek(&Some(locator), Bias::Left);
6294        if let Some(excerpt) = cursor.item()
6295            && excerpt.id == excerpt_id
6296        {
6297            return Some(excerpt);
6298        }
6299        None
6300    }
6301
6302    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6303    pub fn excerpt_containing<T: ToOffset>(
6304        &self,
6305        range: Range<T>,
6306    ) -> Option<MultiBufferExcerpt<'_>> {
6307        let range = range.start.to_offset(self)..range.end.to_offset(self);
6308        let mut cursor = self.cursor::<usize>();
6309        cursor.seek(&range.start);
6310
6311        let start_excerpt = cursor.excerpt()?;
6312        if range.end != range.start {
6313            cursor.seek_forward(&range.end);
6314            if cursor.excerpt()?.id != start_excerpt.id {
6315                return None;
6316            }
6317        }
6318
6319        cursor.seek_to_start_of_current_excerpt();
6320        let region = cursor.region()?;
6321        let offset = region.range.start;
6322        let buffer_offset = start_excerpt.buffer_start_offset();
6323        let excerpt_offset = cursor.excerpts.start().clone();
6324        Some(MultiBufferExcerpt {
6325            diff_transforms: cursor.diff_transforms,
6326            excerpt: start_excerpt,
6327            offset,
6328            buffer_offset,
6329            excerpt_offset,
6330        })
6331    }
6332
6333    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6334        if let Some(id) = anchor.buffer_id {
6335            return Some(id);
6336        }
6337        let excerpt = self.excerpt_containing(anchor..anchor)?;
6338        Some(excerpt.buffer_id())
6339    }
6340
6341    pub fn selections_in_range<'a>(
6342        &'a self,
6343        range: &'a Range<Anchor>,
6344        include_local: bool,
6345    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6346        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6347        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6348        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6349        cursor.seek(start_locator, Bias::Left);
6350        cursor
6351            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6352            .flat_map(move |excerpt| {
6353                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6354                if excerpt.id == range.start.excerpt_id {
6355                    query_range.start = range.start.text_anchor;
6356                }
6357                if excerpt.id == range.end.excerpt_id {
6358                    query_range.end = range.end.text_anchor;
6359                }
6360
6361                excerpt
6362                    .buffer
6363                    .selections_in_range(query_range, include_local)
6364                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6365                        selections.map(move |selection| {
6366                            let mut start = Anchor {
6367                                buffer_id: Some(excerpt.buffer_id),
6368                                excerpt_id: excerpt.id,
6369                                text_anchor: selection.start,
6370                                diff_base_anchor: None,
6371                            };
6372                            let mut end = Anchor {
6373                                buffer_id: Some(excerpt.buffer_id),
6374                                excerpt_id: excerpt.id,
6375                                text_anchor: selection.end,
6376                                diff_base_anchor: None,
6377                            };
6378                            if range.start.cmp(&start, self).is_gt() {
6379                                start = range.start;
6380                            }
6381                            if range.end.cmp(&end, self).is_lt() {
6382                                end = range.end;
6383                            }
6384
6385                            (
6386                                replica_id,
6387                                line_mode,
6388                                cursor_shape,
6389                                Selection {
6390                                    id: selection.id,
6391                                    start,
6392                                    end,
6393                                    reversed: selection.reversed,
6394                                    goal: selection.goal,
6395                                },
6396                            )
6397                        })
6398                    })
6399            })
6400    }
6401
6402    pub fn show_headers(&self) -> bool {
6403        self.show_headers
6404    }
6405
6406    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6407        self.diffs.get(&buffer_id)
6408    }
6409
6410    /// Visually annotates a position or range with the `Debug` representation of a value. The
6411    /// callsite of this function is used as a key - previous annotations will be removed.
6412    #[cfg(debug_assertions)]
6413    #[track_caller]
6414    pub fn debug<V, R>(&self, ranges: &R, value: V)
6415    where
6416        R: debug::ToMultiBufferDebugRanges,
6417        V: std::fmt::Debug,
6418    {
6419        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6420    }
6421
6422    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6423    /// debug annotations with the same key will be removed. The key is also used to determine the
6424    /// annotation's color.
6425    #[cfg(debug_assertions)]
6426    #[track_caller]
6427    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6428    where
6429        K: std::hash::Hash + 'static,
6430        R: debug::ToMultiBufferDebugRanges,
6431        V: std::fmt::Debug,
6432    {
6433        let text_ranges = ranges
6434            .to_multi_buffer_debug_ranges(self)
6435            .into_iter()
6436            .flat_map(|range| {
6437                self.range_to_buffer_ranges(range).into_iter().map(
6438                    |(buffer, range, _excerpt_id)| {
6439                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6440                    },
6441                )
6442            })
6443            .collect();
6444        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6445            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6446        });
6447    }
6448}
6449
6450#[cfg(any(test, feature = "test-support"))]
6451impl MultiBufferSnapshot {
6452    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6453        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6454        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6455        start..end
6456    }
6457
6458    #[cfg(any(test, feature = "test-support"))]
6459    fn check_invariants(&self) {
6460        let excerpts = self.excerpts.items(&());
6461        let excerpt_ids = self.excerpt_ids.items(&());
6462
6463        for (ix, excerpt) in excerpts.iter().enumerate() {
6464            if ix == 0 {
6465                if excerpt.locator <= Locator::min() {
6466                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6467                }
6468            } else if excerpt.locator <= excerpts[ix - 1].locator {
6469                panic!("excerpts are out-of-order: {:?}", excerpts);
6470            }
6471        }
6472
6473        for (ix, entry) in excerpt_ids.iter().enumerate() {
6474            if ix == 0 {
6475                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6476                    panic!("invalid first excerpt id {:?}", entry.id);
6477                }
6478            } else if entry.id <= excerpt_ids[ix - 1].id {
6479                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6480            }
6481        }
6482
6483        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6484            panic!(
6485                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6486                self.excerpts.summary().text.len,
6487                self.diff_transforms.summary().input,
6488                self.diff_transforms.items(&()),
6489            );
6490        }
6491
6492        let mut prev_transform: Option<&DiffTransform> = None;
6493        for item in self.diff_transforms.iter() {
6494            if let DiffTransform::BufferContent {
6495                summary,
6496                inserted_hunk_info,
6497            } = item
6498            {
6499                if let Some(DiffTransform::BufferContent {
6500                    inserted_hunk_info: prev_inserted_hunk_info,
6501                    ..
6502                }) = prev_transform
6503                    && *inserted_hunk_info == *prev_inserted_hunk_info
6504                {
6505                    panic!(
6506                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6507                        self.diff_transforms.items(&())
6508                    );
6509                }
6510                if summary.len == 0 && !self.is_empty() {
6511                    panic!("empty buffer content transform");
6512                }
6513            }
6514            prev_transform = Some(item);
6515        }
6516    }
6517}
6518
6519impl<'a, D> MultiBufferCursor<'a, D>
6520where
6521    D: TextDimension + Ord + Sub<D, Output = D>,
6522{
6523    fn seek(&mut self, position: &D) {
6524        self.cached_region.take();
6525        self.diff_transforms
6526            .seek(&OutputDimension(*position), Bias::Right);
6527        if self.diff_transforms.item().is_none()
6528            && *position == self.diff_transforms.start().output_dimension.0
6529        {
6530            self.diff_transforms.prev();
6531        }
6532
6533        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6534        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6535            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6536            excerpt_position.add_assign(&overshoot);
6537        }
6538
6539        self.excerpts
6540            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
6541        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6542            self.excerpts.prev();
6543        }
6544    }
6545
6546    fn seek_forward(&mut self, position: &D) {
6547        self.cached_region.take();
6548        self.diff_transforms
6549            .seek_forward(&OutputDimension(*position), Bias::Right);
6550        if self.diff_transforms.item().is_none()
6551            && *position == self.diff_transforms.start().output_dimension.0
6552        {
6553            self.diff_transforms.prev();
6554        }
6555
6556        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6557        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6558        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6559            excerpt_position.add_assign(&overshoot);
6560        }
6561
6562        self.excerpts
6563            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
6564        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6565            self.excerpts.prev();
6566        }
6567    }
6568
6569    fn next_excerpt(&mut self) {
6570        self.excerpts.next();
6571        self.seek_to_start_of_current_excerpt();
6572    }
6573
6574    fn prev_excerpt(&mut self) {
6575        self.excerpts.prev();
6576        self.seek_to_start_of_current_excerpt();
6577    }
6578
6579    fn seek_to_start_of_current_excerpt(&mut self) {
6580        self.cached_region.take();
6581        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6582        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6583            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6584            && self.diff_transforms.next_item().is_some()
6585        {
6586            self.diff_transforms.next();
6587        }
6588    }
6589
6590    fn next(&mut self) {
6591        self.cached_region.take();
6592        match self
6593            .diff_transforms
6594            .end()
6595            .excerpt_dimension
6596            .cmp(&self.excerpts.end())
6597        {
6598            cmp::Ordering::Less => self.diff_transforms.next(),
6599            cmp::Ordering::Greater => self.excerpts.next(),
6600            cmp::Ordering::Equal => {
6601                self.diff_transforms.next();
6602                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6603                    || self.diff_transforms.item().is_none()
6604                {
6605                    self.excerpts.next();
6606                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6607                    self.diff_transforms.item()
6608                    && self
6609                        .excerpts
6610                        .item()
6611                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6612                {
6613                    self.excerpts.next();
6614                }
6615            }
6616        }
6617    }
6618
6619    fn prev(&mut self) {
6620        self.cached_region.take();
6621        match self
6622            .diff_transforms
6623            .start()
6624            .excerpt_dimension
6625            .cmp(self.excerpts.start())
6626        {
6627            cmp::Ordering::Less => self.excerpts.prev(),
6628            cmp::Ordering::Greater => self.diff_transforms.prev(),
6629            cmp::Ordering::Equal => {
6630                self.diff_transforms.prev();
6631                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6632                    || self.diff_transforms.item().is_none()
6633                {
6634                    self.excerpts.prev();
6635                }
6636            }
6637        }
6638    }
6639
6640    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6641        if self.cached_region.is_none() {
6642            self.cached_region = self.build_region();
6643        }
6644        self.cached_region.clone()
6645    }
6646
6647    fn is_at_start_of_excerpt(&mut self) -> bool {
6648        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6649            return false;
6650        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6651            return true;
6652        }
6653
6654        self.diff_transforms.prev();
6655        let prev_transform = self.diff_transforms.item();
6656        self.diff_transforms.next();
6657
6658        prev_transform.is_none_or(|next_transform| {
6659            matches!(next_transform, DiffTransform::BufferContent { .. })
6660        })
6661    }
6662
6663    fn is_at_end_of_excerpt(&mut self) -> bool {
6664        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6665            return false;
6666        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6667            || self.diff_transforms.item().is_none()
6668        {
6669            return true;
6670        }
6671
6672        let next_transform = self.diff_transforms.next_item();
6673        next_transform.is_none_or(|next_transform| match next_transform {
6674            DiffTransform::BufferContent { .. } => true,
6675            DiffTransform::DeletedHunk { hunk_info, .. } => self
6676                .excerpts
6677                .item()
6678                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6679        })
6680    }
6681
6682    fn main_buffer_position(&self) -> Option<D> {
6683        let excerpt = self.excerpts.item()?;
6684        let buffer = &excerpt.buffer;
6685        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6686        let mut buffer_start = buffer_context_start;
6687        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6688        buffer_start.add_assign(&overshoot);
6689        Some(buffer_start)
6690    }
6691
6692    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6693        let excerpt = self.excerpts.item()?;
6694        match self.diff_transforms.item()? {
6695            DiffTransform::DeletedHunk {
6696                buffer_id,
6697                base_text_byte_range,
6698                has_trailing_newline,
6699                hunk_info,
6700                ..
6701            } => {
6702                let diff = self.diffs.get(buffer_id)?;
6703                let buffer = diff.base_text();
6704                let mut rope_cursor = buffer.as_rope().cursor(0);
6705                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6706                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6707                let mut buffer_end = buffer_start;
6708                buffer_end.add_assign(&buffer_range_len);
6709                let start = self.diff_transforms.start().output_dimension.0;
6710                let end = self.diff_transforms.end().output_dimension.0;
6711                Some(MultiBufferRegion {
6712                    buffer,
6713                    excerpt,
6714                    has_trailing_newline: *has_trailing_newline,
6715                    is_main_buffer: false,
6716                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6717                        hunk_info.hunk_secondary_status,
6718                    )),
6719                    buffer_range: buffer_start..buffer_end,
6720                    range: start..end,
6721                })
6722            }
6723            DiffTransform::BufferContent {
6724                inserted_hunk_info, ..
6725            } => {
6726                let buffer = &excerpt.buffer;
6727                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6728
6729                let mut start = self.diff_transforms.start().output_dimension.0;
6730                let mut buffer_start = buffer_context_start;
6731                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6732                    let overshoot =
6733                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6734                    start.add_assign(&overshoot);
6735                } else {
6736                    let overshoot =
6737                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6738                    buffer_start.add_assign(&overshoot);
6739                }
6740
6741                let mut end;
6742                let mut buffer_end;
6743                let has_trailing_newline;
6744                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6745                    let overshoot =
6746                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6747                    end = self.diff_transforms.end().output_dimension.0;
6748                    buffer_end = buffer_context_start;
6749                    buffer_end.add_assign(&overshoot);
6750                    has_trailing_newline = false;
6751                } else {
6752                    let overshoot =
6753                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6754                    end = self.diff_transforms.start().output_dimension.0;
6755                    end.add_assign(&overshoot);
6756                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6757                    has_trailing_newline = excerpt.has_trailing_newline;
6758                };
6759
6760                Some(MultiBufferRegion {
6761                    buffer,
6762                    excerpt,
6763                    has_trailing_newline,
6764                    is_main_buffer: true,
6765                    diff_hunk_status: inserted_hunk_info
6766                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6767                    buffer_range: buffer_start..buffer_end,
6768                    range: start..end,
6769                })
6770            }
6771        }
6772    }
6773
6774    fn excerpt(&self) -> Option<&'a Excerpt> {
6775        self.excerpts.item()
6776    }
6777}
6778
6779impl History {
6780    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6781        self.transaction_depth += 1;
6782        if self.transaction_depth == 1 {
6783            let id = self.next_transaction_id.tick();
6784            self.undo_stack.push(Transaction {
6785                id,
6786                buffer_transactions: Default::default(),
6787                first_edit_at: now,
6788                last_edit_at: now,
6789                suppress_grouping: false,
6790            });
6791            Some(id)
6792        } else {
6793            None
6794        }
6795    }
6796
6797    fn end_transaction(
6798        &mut self,
6799        now: Instant,
6800        buffer_transactions: HashMap<BufferId, TransactionId>,
6801    ) -> bool {
6802        assert_ne!(self.transaction_depth, 0);
6803        self.transaction_depth -= 1;
6804        if self.transaction_depth == 0 {
6805            if buffer_transactions.is_empty() {
6806                self.undo_stack.pop();
6807                false
6808            } else {
6809                self.redo_stack.clear();
6810                let transaction = self.undo_stack.last_mut().unwrap();
6811                transaction.last_edit_at = now;
6812                for (buffer_id, transaction_id) in buffer_transactions {
6813                    transaction
6814                        .buffer_transactions
6815                        .entry(buffer_id)
6816                        .or_insert(transaction_id);
6817                }
6818                true
6819            }
6820        } else {
6821            false
6822        }
6823    }
6824
6825    fn push_transaction<'a, T>(
6826        &mut self,
6827        buffer_transactions: T,
6828        now: Instant,
6829        cx: &Context<MultiBuffer>,
6830    ) where
6831        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6832    {
6833        assert_eq!(self.transaction_depth, 0);
6834        let transaction = Transaction {
6835            id: self.next_transaction_id.tick(),
6836            buffer_transactions: buffer_transactions
6837                .into_iter()
6838                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6839                .collect(),
6840            first_edit_at: now,
6841            last_edit_at: now,
6842            suppress_grouping: false,
6843        };
6844        if !transaction.buffer_transactions.is_empty() {
6845            self.undo_stack.push(transaction);
6846            self.redo_stack.clear();
6847        }
6848    }
6849
6850    fn finalize_last_transaction(&mut self) {
6851        if let Some(transaction) = self.undo_stack.last_mut() {
6852            transaction.suppress_grouping = true;
6853        }
6854    }
6855
6856    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6857        if let Some(ix) = self
6858            .undo_stack
6859            .iter()
6860            .rposition(|transaction| transaction.id == transaction_id)
6861        {
6862            Some(self.undo_stack.remove(ix))
6863        } else if let Some(ix) = self
6864            .redo_stack
6865            .iter()
6866            .rposition(|transaction| transaction.id == transaction_id)
6867        {
6868            Some(self.redo_stack.remove(ix))
6869        } else {
6870            None
6871        }
6872    }
6873
6874    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6875        self.undo_stack
6876            .iter()
6877            .find(|transaction| transaction.id == transaction_id)
6878            .or_else(|| {
6879                self.redo_stack
6880                    .iter()
6881                    .find(|transaction| transaction.id == transaction_id)
6882            })
6883    }
6884
6885    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6886        self.undo_stack
6887            .iter_mut()
6888            .find(|transaction| transaction.id == transaction_id)
6889            .or_else(|| {
6890                self.redo_stack
6891                    .iter_mut()
6892                    .find(|transaction| transaction.id == transaction_id)
6893            })
6894    }
6895
6896    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6897        assert_eq!(self.transaction_depth, 0);
6898        if let Some(transaction) = self.undo_stack.pop() {
6899            self.redo_stack.push(transaction);
6900            self.redo_stack.last_mut()
6901        } else {
6902            None
6903        }
6904    }
6905
6906    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6907        assert_eq!(self.transaction_depth, 0);
6908        if let Some(transaction) = self.redo_stack.pop() {
6909            self.undo_stack.push(transaction);
6910            self.undo_stack.last_mut()
6911        } else {
6912            None
6913        }
6914    }
6915
6916    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6917        let ix = self
6918            .undo_stack
6919            .iter()
6920            .rposition(|transaction| transaction.id == transaction_id)?;
6921        let transaction = self.undo_stack.remove(ix);
6922        self.redo_stack.push(transaction);
6923        self.redo_stack.last()
6924    }
6925
6926    fn group(&mut self) -> Option<TransactionId> {
6927        let mut count = 0;
6928        let mut transactions = self.undo_stack.iter();
6929        if let Some(mut transaction) = transactions.next_back() {
6930            while let Some(prev_transaction) = transactions.next_back() {
6931                if !prev_transaction.suppress_grouping
6932                    && transaction.first_edit_at - prev_transaction.last_edit_at
6933                        <= self.group_interval
6934                {
6935                    transaction = prev_transaction;
6936                    count += 1;
6937                } else {
6938                    break;
6939                }
6940            }
6941        }
6942        self.group_trailing(count)
6943    }
6944
6945    fn group_until(&mut self, transaction_id: TransactionId) {
6946        let mut count = 0;
6947        for transaction in self.undo_stack.iter().rev() {
6948            if transaction.id == transaction_id {
6949                self.group_trailing(count);
6950                break;
6951            } else if transaction.suppress_grouping {
6952                break;
6953            } else {
6954                count += 1;
6955            }
6956        }
6957    }
6958
6959    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6960        let new_len = self.undo_stack.len() - n;
6961        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6962        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6963            if let Some(transaction) = transactions_to_merge.last() {
6964                last_transaction.last_edit_at = transaction.last_edit_at;
6965            }
6966            for to_merge in transactions_to_merge {
6967                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6968                    last_transaction
6969                        .buffer_transactions
6970                        .entry(*buffer_id)
6971                        .or_insert(*transaction_id);
6972                }
6973            }
6974        }
6975
6976        self.undo_stack.truncate(new_len);
6977        self.undo_stack.last().map(|t| t.id)
6978    }
6979}
6980
6981impl Excerpt {
6982    fn new(
6983        id: ExcerptId,
6984        locator: Locator,
6985        buffer_id: BufferId,
6986        buffer: BufferSnapshot,
6987        range: ExcerptRange<text::Anchor>,
6988        has_trailing_newline: bool,
6989    ) -> Self {
6990        Excerpt {
6991            id,
6992            locator,
6993            max_buffer_row: range.context.end.to_point(&buffer).row,
6994            text_summary: buffer
6995                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6996            buffer_id,
6997            buffer,
6998            range,
6999            has_trailing_newline,
7000        }
7001    }
7002
7003    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7004        let content_start = self.range.context.start.to_offset(&self.buffer);
7005        let chunks_start = content_start + range.start;
7006        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7007
7008        let footer_height = if self.has_trailing_newline
7009            && range.start <= self.text_summary.len
7010            && range.end > self.text_summary.len
7011        {
7012            1
7013        } else {
7014            0
7015        };
7016
7017        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7018
7019        ExcerptChunks {
7020            excerpt_id: self.id,
7021            content_chunks,
7022            footer_height,
7023        }
7024    }
7025
7026    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7027        let content_start = self.range.context.start.to_offset(&self.buffer);
7028        let chunks_start = content_start + range.start;
7029        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7030        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7031        excerpt_chunks.footer_height = if self.has_trailing_newline
7032            && range.start <= self.text_summary.len
7033            && range.end > self.text_summary.len
7034        {
7035            1
7036        } else {
7037            0
7038        };
7039    }
7040
7041    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7042        if text_anchor
7043            .cmp(&self.range.context.start, &self.buffer)
7044            .is_lt()
7045        {
7046            self.range.context.start
7047        } else if text_anchor
7048            .cmp(&self.range.context.end, &self.buffer)
7049            .is_gt()
7050        {
7051            self.range.context.end
7052        } else {
7053            text_anchor
7054        }
7055    }
7056
7057    fn contains(&self, anchor: &Anchor) -> bool {
7058        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
7059            && self
7060                .range
7061                .context
7062                .start
7063                .cmp(&anchor.text_anchor, &self.buffer)
7064                .is_le()
7065            && self
7066                .range
7067                .context
7068                .end
7069                .cmp(&anchor.text_anchor, &self.buffer)
7070                .is_ge()
7071    }
7072
7073    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7074    fn buffer_start_offset(&self) -> usize {
7075        self.range.context.start.to_offset(&self.buffer)
7076    }
7077
7078    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7079    fn buffer_end_offset(&self) -> usize {
7080        self.buffer_start_offset() + self.text_summary.len
7081    }
7082}
7083
7084impl<'a> MultiBufferExcerpt<'a> {
7085    pub fn id(&self) -> ExcerptId {
7086        self.excerpt.id
7087    }
7088
7089    pub fn buffer_id(&self) -> BufferId {
7090        self.excerpt.buffer_id
7091    }
7092
7093    pub fn start_anchor(&self) -> Anchor {
7094        Anchor {
7095            buffer_id: Some(self.excerpt.buffer_id),
7096            excerpt_id: self.excerpt.id,
7097            text_anchor: self.excerpt.range.context.start,
7098            diff_base_anchor: None,
7099        }
7100    }
7101
7102    pub fn end_anchor(&self) -> Anchor {
7103        Anchor {
7104            buffer_id: Some(self.excerpt.buffer_id),
7105            excerpt_id: self.excerpt.id,
7106            text_anchor: self.excerpt.range.context.end,
7107            diff_base_anchor: None,
7108        }
7109    }
7110
7111    pub fn buffer(&self) -> &'a BufferSnapshot {
7112        &self.excerpt.buffer
7113    }
7114
7115    pub fn buffer_range(&self) -> Range<usize> {
7116        self.buffer_offset
7117            ..self
7118                .excerpt
7119                .range
7120                .context
7121                .end
7122                .to_offset(&self.excerpt.buffer.text)
7123    }
7124
7125    pub fn start_offset(&self) -> usize {
7126        self.offset
7127    }
7128
7129    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7130    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
7131        self.map_range_to_buffer(offset..offset).start
7132    }
7133
7134    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7135    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
7136        self.diff_transforms
7137            .seek(&OutputDimension(range.start), Bias::Right);
7138        let start = self.map_offset_to_buffer_internal(range.start);
7139        let end = if range.end > range.start {
7140            self.diff_transforms
7141                .seek_forward(&OutputDimension(range.end), Bias::Right);
7142            self.map_offset_to_buffer_internal(range.end)
7143        } else {
7144            start
7145        };
7146        start..end
7147    }
7148
7149    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
7150        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
7151        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7152            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
7153        };
7154        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
7155        self.buffer_offset + offset_in_excerpt
7156    }
7157
7158    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7159    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
7160        self.map_range_from_buffer(buffer_offset..buffer_offset)
7161            .start
7162    }
7163
7164    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7165    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
7166        if buffer_range.start < self.buffer_offset {
7167            log::warn!(
7168                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7169            );
7170            return buffer_range;
7171        }
7172        let overshoot = buffer_range.start - self.buffer_offset;
7173        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7174        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
7175        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
7176            log::warn!(
7177                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7178            );
7179            return buffer_range;
7180        }
7181        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7182        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7183
7184        let end = if buffer_range.end > buffer_range.start {
7185            let overshoot = buffer_range.end - self.buffer_offset;
7186            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7187            self.diff_transforms
7188                .seek_forward(&excerpt_offset, Bias::Right);
7189            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7190            self.diff_transforms.start().output_dimension.0 + overshoot
7191        } else {
7192            start
7193        };
7194
7195        start..end
7196    }
7197
7198    /// Returns true if the entirety of the given range is in the buffer's excerpt
7199    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
7200        range.start >= self.excerpt.buffer_start_offset()
7201            && range.end <= self.excerpt.buffer_end_offset()
7202    }
7203
7204    pub fn max_buffer_row(&self) -> u32 {
7205        self.excerpt.max_buffer_row
7206    }
7207}
7208
7209impl ExcerptId {
7210    pub fn min() -> Self {
7211        Self(0)
7212    }
7213
7214    pub fn max() -> Self {
7215        Self(usize::MAX)
7216    }
7217
7218    pub fn to_proto(self) -> u64 {
7219        self.0 as _
7220    }
7221
7222    pub fn from_proto(proto: u64) -> Self {
7223        Self(proto as _)
7224    }
7225
7226    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7227        let a = snapshot.excerpt_locator_for_id(*self);
7228        let b = snapshot.excerpt_locator_for_id(*other);
7229        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7230    }
7231}
7232
7233impl From<ExcerptId> for usize {
7234    fn from(val: ExcerptId) -> Self {
7235        val.0
7236    }
7237}
7238
7239impl fmt::Debug for Excerpt {
7240    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7241        f.debug_struct("Excerpt")
7242            .field("id", &self.id)
7243            .field("locator", &self.locator)
7244            .field("buffer_id", &self.buffer_id)
7245            .field("range", &self.range)
7246            .field("text_summary", &self.text_summary)
7247            .field("has_trailing_newline", &self.has_trailing_newline)
7248            .finish()
7249    }
7250}
7251
7252impl sum_tree::Item for Excerpt {
7253    type Summary = ExcerptSummary;
7254
7255    fn summary(&self, _cx: &()) -> Self::Summary {
7256        let mut text = self.text_summary;
7257        if self.has_trailing_newline {
7258            text += TextSummary::from("\n");
7259        }
7260        ExcerptSummary {
7261            excerpt_id: self.id,
7262            excerpt_locator: self.locator.clone(),
7263            widest_line_number: self.max_buffer_row,
7264            text,
7265        }
7266    }
7267}
7268
7269impl sum_tree::Item for ExcerptIdMapping {
7270    type Summary = ExcerptId;
7271
7272    fn summary(&self, _cx: &()) -> Self::Summary {
7273        self.id
7274    }
7275}
7276
7277impl sum_tree::KeyedItem for ExcerptIdMapping {
7278    type Key = ExcerptId;
7279
7280    fn key(&self) -> Self::Key {
7281        self.id
7282    }
7283}
7284
7285impl DiffTransform {
7286    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7287        match self {
7288            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7289            DiffTransform::BufferContent {
7290                inserted_hunk_info, ..
7291            } => *inserted_hunk_info,
7292        }
7293    }
7294}
7295
7296impl sum_tree::Item for DiffTransform {
7297    type Summary = DiffTransformSummary;
7298
7299    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7300        match self {
7301            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7302                input: *summary,
7303                output: *summary,
7304            },
7305            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7306                input: TextSummary::default(),
7307                output: *summary,
7308            },
7309        }
7310    }
7311}
7312
7313impl DiffTransformSummary {
7314    fn excerpt_len(&self) -> ExcerptOffset {
7315        ExcerptOffset::new(self.input.len)
7316    }
7317}
7318
7319impl sum_tree::Summary for DiffTransformSummary {
7320    type Context = ();
7321
7322    fn zero(_: &Self::Context) -> Self {
7323        DiffTransformSummary {
7324            input: TextSummary::default(),
7325            output: TextSummary::default(),
7326        }
7327    }
7328
7329    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7330        self.input += &summary.input;
7331        self.output += &summary.output;
7332    }
7333}
7334
7335impl sum_tree::Summary for ExcerptId {
7336    type Context = ();
7337
7338    fn zero(_cx: &()) -> Self {
7339        Default::default()
7340    }
7341
7342    fn add_summary(&mut self, other: &Self, _: &()) {
7343        *self = *other;
7344    }
7345}
7346
7347impl sum_tree::Summary for ExcerptSummary {
7348    type Context = ();
7349
7350    fn zero(_cx: &()) -> Self {
7351        Default::default()
7352    }
7353
7354    fn add_summary(&mut self, summary: &Self, _: &()) {
7355        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7356        self.excerpt_locator = summary.excerpt_locator.clone();
7357        Summary::add_summary(&mut self.text, &summary.text, &());
7358        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7359    }
7360}
7361
7362impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7363    fn zero(_cx: &()) -> Self {
7364        Default::default()
7365    }
7366
7367    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7368        self.value += summary.text.len;
7369    }
7370}
7371
7372impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7373    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7374        Ord::cmp(&self.value, &cursor_location.text.len)
7375    }
7376}
7377
7378impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7379    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7380        Ord::cmp(&Some(self), cursor_location)
7381    }
7382}
7383
7384impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7385    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7386        Ord::cmp(self, &cursor_location.excerpt_locator)
7387    }
7388}
7389
7390impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7391    fn zero(_cx: &()) -> Self {
7392        Default::default()
7393    }
7394
7395    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7396        self.value += summary.text.lines;
7397    }
7398}
7399
7400impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7401    for ExcerptDimension<D>
7402{
7403    fn zero(_: &()) -> Self {
7404        ExcerptDimension(D::default())
7405    }
7406
7407    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7408        self.0.add_assign(&D::from_text_summary(&summary.text))
7409    }
7410}
7411
7412impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7413    fn zero(_cx: &()) -> Self {
7414        Default::default()
7415    }
7416
7417    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7418        *self = Some(&summary.excerpt_locator);
7419    }
7420}
7421
7422impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7423    fn zero(_cx: &()) -> Self {
7424        Default::default()
7425    }
7426
7427    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7428        *self = Some(summary.excerpt_id);
7429    }
7430}
7431
7432#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7433struct ExcerptDimension<T>(T);
7434
7435#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7436struct OutputDimension<T>(T);
7437
7438impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7439    fn zero(_: &()) -> Self {
7440        ExcerptOffset::new(0)
7441    }
7442
7443    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7444        self.value += summary.input.len;
7445    }
7446}
7447
7448impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7449    fn zero(_: &()) -> Self {
7450        ExcerptPoint::new(0, 0)
7451    }
7452
7453    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7454        self.value += summary.input.lines;
7455    }
7456}
7457
7458impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7459    for ExcerptDimension<D>
7460{
7461    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7462        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7463    }
7464}
7465
7466impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7467    for ExcerptDimension<D>
7468{
7469    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7470        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7471    }
7472}
7473
7474impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7475    fn zero(_: &()) -> Self {
7476        ExcerptDimension(D::default())
7477    }
7478
7479    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7480        self.0.add_assign(&D::from_text_summary(&summary.input))
7481    }
7482}
7483
7484impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7485    for OutputDimension<D>
7486{
7487    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7488        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7489    }
7490}
7491
7492impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7493    fn zero(_: &()) -> Self {
7494        OutputDimension(D::default())
7495    }
7496
7497    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7498        self.0.add_assign(&D::from_text_summary(&summary.output))
7499    }
7500}
7501
7502impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7503    fn zero(_: &()) -> Self {
7504        TextSummary::default()
7505    }
7506
7507    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7508        *self += summary.output
7509    }
7510}
7511
7512impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7513    fn zero(_: &()) -> Self {
7514        0
7515    }
7516
7517    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7518        *self += summary.output.len
7519    }
7520}
7521
7522impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7523    fn zero(_: &()) -> Self {
7524        Point::new(0, 0)
7525    }
7526
7527    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7528        *self += summary.output.lines
7529    }
7530}
7531
7532impl MultiBufferRows<'_> {
7533    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7534        self.point = Point::new(row, 0);
7535        self.cursor.seek(&self.point);
7536    }
7537}
7538
7539impl Iterator for MultiBufferRows<'_> {
7540    type Item = RowInfo;
7541
7542    fn next(&mut self) -> Option<Self::Item> {
7543        if self.is_empty && self.point.row == 0 {
7544            self.point += Point::new(1, 0);
7545            return Some(RowInfo {
7546                buffer_id: None,
7547                buffer_row: Some(0),
7548                multibuffer_row: Some(MultiBufferRow(0)),
7549                diff_status: None,
7550                expand_info: None,
7551            });
7552        }
7553
7554        let mut region = self.cursor.region()?;
7555        while self.point >= region.range.end {
7556            self.cursor.next();
7557            if let Some(next_region) = self.cursor.region() {
7558                region = next_region;
7559            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7560                let multibuffer_row = MultiBufferRow(self.point.row);
7561                let last_excerpt = self
7562                    .cursor
7563                    .excerpts
7564                    .item()
7565                    .or(self.cursor.excerpts.prev_item())?;
7566                let last_row = last_excerpt
7567                    .range
7568                    .context
7569                    .end
7570                    .to_point(&last_excerpt.buffer)
7571                    .row;
7572
7573                let first_row = last_excerpt
7574                    .range
7575                    .context
7576                    .start
7577                    .to_point(&last_excerpt.buffer)
7578                    .row;
7579
7580                let expand_info = if self.is_singleton {
7581                    None
7582                } else {
7583                    let needs_expand_up = first_row == last_row
7584                        && last_row > 0
7585                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7586                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7587
7588                    if needs_expand_up && needs_expand_down {
7589                        Some(ExpandExcerptDirection::UpAndDown)
7590                    } else if needs_expand_up {
7591                        Some(ExpandExcerptDirection::Up)
7592                    } else if needs_expand_down {
7593                        Some(ExpandExcerptDirection::Down)
7594                    } else {
7595                        None
7596                    }
7597                    .map(|direction| ExpandInfo {
7598                        direction,
7599                        excerpt_id: last_excerpt.id,
7600                    })
7601                };
7602                self.point += Point::new(1, 0);
7603                return Some(RowInfo {
7604                    buffer_id: Some(last_excerpt.buffer_id),
7605                    buffer_row: Some(last_row),
7606                    multibuffer_row: Some(multibuffer_row),
7607                    diff_status: None,
7608                    expand_info,
7609                });
7610            } else {
7611                return None;
7612            };
7613        }
7614
7615        let overshoot = self.point - region.range.start;
7616        let buffer_point = region.buffer_range.start + overshoot;
7617        let expand_info = if self.is_singleton {
7618            None
7619        } else {
7620            let needs_expand_up = self.point.row == region.range.start.row
7621                && self.cursor.is_at_start_of_excerpt()
7622                && buffer_point.row > 0;
7623            let needs_expand_down = (region.excerpt.has_trailing_newline
7624                && self.point.row + 1 == region.range.end.row
7625                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7626                && self.cursor.is_at_end_of_excerpt()
7627                && buffer_point.row < region.buffer.max_point().row;
7628
7629            if needs_expand_up && needs_expand_down {
7630                Some(ExpandExcerptDirection::UpAndDown)
7631            } else if needs_expand_up {
7632                Some(ExpandExcerptDirection::Up)
7633            } else if needs_expand_down {
7634                Some(ExpandExcerptDirection::Down)
7635            } else {
7636                None
7637            }
7638            .map(|direction| ExpandInfo {
7639                direction,
7640                excerpt_id: region.excerpt.id,
7641            })
7642        };
7643
7644        let result = Some(RowInfo {
7645            buffer_id: Some(region.buffer.remote_id()),
7646            buffer_row: Some(buffer_point.row),
7647            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7648            diff_status: region
7649                .diff_hunk_status
7650                .filter(|_| self.point < region.range.end),
7651            expand_info,
7652        });
7653        self.point += Point::new(1, 0);
7654        result
7655    }
7656}
7657
7658impl<'a> MultiBufferChunks<'a> {
7659    pub fn offset(&self) -> usize {
7660        self.range.start
7661    }
7662
7663    pub fn seek(&mut self, range: Range<usize>) {
7664        self.diff_transforms.seek(&range.end, Bias::Right);
7665        let mut excerpt_end = self.diff_transforms.start().1;
7666        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7667            let overshoot = range.end - self.diff_transforms.start().0;
7668            excerpt_end.value += overshoot;
7669        }
7670
7671        self.diff_transforms.seek(&range.start, Bias::Right);
7672        let mut excerpt_start = self.diff_transforms.start().1;
7673        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7674            let overshoot = range.start - self.diff_transforms.start().0;
7675            excerpt_start.value += overshoot;
7676        }
7677
7678        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7679        self.buffer_chunk.take();
7680        self.range = range;
7681    }
7682
7683    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7684        self.excerpt_offset_range = new_range.clone();
7685        self.excerpts.seek(&new_range.start, Bias::Right);
7686        if let Some(excerpt) = self.excerpts.item() {
7687            let excerpt_start = *self.excerpts.start();
7688            if let Some(excerpt_chunks) = self
7689                .excerpt_chunks
7690                .as_mut()
7691                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7692            {
7693                excerpt.seek_chunks(
7694                    excerpt_chunks,
7695                    (self.excerpt_offset_range.start - excerpt_start).value
7696                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7697                );
7698            } else {
7699                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7700                    (self.excerpt_offset_range.start - excerpt_start).value
7701                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7702                    self.language_aware,
7703                ));
7704            }
7705        } else {
7706            self.excerpt_chunks = None;
7707        }
7708    }
7709
7710    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7711        loop {
7712            if self.excerpt_offset_range.is_empty() {
7713                return None;
7714            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7715                self.excerpt_offset_range.start.value += chunk.text.len();
7716                return Some(chunk);
7717            } else {
7718                self.excerpts.next();
7719                let excerpt = self.excerpts.item()?;
7720                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7721                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7722                    self.language_aware,
7723                ));
7724            }
7725        }
7726    }
7727}
7728
7729impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7730    type Item = &'a str;
7731
7732    fn next(&mut self) -> Option<Self::Item> {
7733        let mut region = self.cursor.region()?;
7734        if self.offset == region.range.start {
7735            self.cursor.prev();
7736            region = self.cursor.region()?;
7737            let start_overshoot = self.start.saturating_sub(region.range.start);
7738            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7739                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7740            ));
7741        }
7742
7743        if self.offset == region.range.end && region.has_trailing_newline {
7744            self.offset -= 1;
7745            Some("\n")
7746        } else {
7747            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7748            self.offset -= chunk.len();
7749            Some(chunk)
7750        }
7751    }
7752}
7753
7754impl<'a> Iterator for MultiBufferChunks<'a> {
7755    type Item = Chunk<'a>;
7756
7757    fn next(&mut self) -> Option<Chunk<'a>> {
7758        if self.range.start >= self.range.end {
7759            return None;
7760        }
7761        if self.range.start == self.diff_transforms.end().0 {
7762            self.diff_transforms.next();
7763        }
7764
7765        let diff_transform_start = self.diff_transforms.start().0;
7766        let diff_transform_end = self.diff_transforms.end().0;
7767        debug_assert!(self.range.start < diff_transform_end);
7768
7769        let diff_transform = self.diff_transforms.item()?;
7770        match diff_transform {
7771            DiffTransform::BufferContent { .. } => {
7772                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7773                    chunk
7774                } else {
7775                    let chunk = self.next_excerpt_chunk().unwrap();
7776                    self.buffer_chunk.insert(chunk)
7777                };
7778
7779                let chunk_end = self.range.start + chunk.text.len();
7780                let diff_transform_end = diff_transform_end.min(self.range.end);
7781
7782                if diff_transform_end < chunk_end {
7783                    let split_idx = diff_transform_end - self.range.start;
7784                    let (before, after) = chunk.text.split_at(split_idx);
7785                    self.range.start = diff_transform_end;
7786                    let mask = (1 << split_idx) - 1;
7787                    let chars = chunk.chars & mask;
7788                    let tabs = chunk.tabs & mask;
7789
7790                    chunk.text = after;
7791                    chunk.chars = chunk.chars >> split_idx;
7792                    chunk.tabs = chunk.tabs >> split_idx;
7793
7794                    Some(Chunk {
7795                        text: before,
7796                        chars,
7797                        tabs,
7798                        ..chunk.clone()
7799                    })
7800                } else {
7801                    self.range.start = chunk_end;
7802                    self.buffer_chunk.take()
7803                }
7804            }
7805            DiffTransform::DeletedHunk {
7806                buffer_id,
7807                base_text_byte_range,
7808                has_trailing_newline,
7809                ..
7810            } => {
7811                let base_text_start =
7812                    base_text_byte_range.start + self.range.start - diff_transform_start;
7813                let base_text_end =
7814                    base_text_byte_range.start + self.range.end - diff_transform_start;
7815                let base_text_end = base_text_end.min(base_text_byte_range.end);
7816
7817                let mut chunks = if let Some((_, mut chunks)) = self
7818                    .diff_base_chunks
7819                    .take()
7820                    .filter(|(id, _)| id == buffer_id)
7821                {
7822                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7823                    {
7824                        chunks.seek(base_text_start..base_text_end);
7825                    }
7826                    chunks
7827                } else {
7828                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7829                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7830                };
7831
7832                let chunk = if let Some(chunk) = chunks.next() {
7833                    self.range.start += chunk.text.len();
7834                    self.diff_base_chunks = Some((*buffer_id, chunks));
7835                    chunk
7836                } else {
7837                    debug_assert!(has_trailing_newline);
7838                    self.range.start += "\n".len();
7839                    Chunk {
7840                        text: "\n",
7841                        chars: 1u128,
7842                        ..Default::default()
7843                    }
7844                };
7845                Some(chunk)
7846            }
7847        }
7848    }
7849}
7850
7851impl MultiBufferBytes<'_> {
7852    fn consume(&mut self, len: usize) {
7853        self.range.start += len;
7854        self.chunk = &self.chunk[len..];
7855
7856        if !self.range.is_empty() && self.chunk.is_empty() {
7857            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7858                self.chunk = chunk;
7859            } else if self.has_trailing_newline {
7860                self.has_trailing_newline = false;
7861                self.chunk = b"\n";
7862            } else {
7863                self.cursor.next();
7864                if let Some(region) = self.cursor.region() {
7865                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7866                        region.buffer_range.start
7867                            ..(region.buffer_range.start + self.range.end - region.range.start)
7868                                .min(region.buffer_range.end),
7869                    );
7870                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7871                    self.excerpt_bytes = Some(excerpt_bytes);
7872                    self.has_trailing_newline =
7873                        region.has_trailing_newline && self.range.end >= region.range.end;
7874                    if self.chunk.is_empty() && self.has_trailing_newline {
7875                        self.has_trailing_newline = false;
7876                        self.chunk = b"\n";
7877                    }
7878                }
7879            }
7880        }
7881    }
7882}
7883
7884impl<'a> Iterator for MultiBufferBytes<'a> {
7885    type Item = &'a [u8];
7886
7887    fn next(&mut self) -> Option<Self::Item> {
7888        let chunk = self.chunk;
7889        if chunk.is_empty() {
7890            None
7891        } else {
7892            self.consume(chunk.len());
7893            Some(chunk)
7894        }
7895    }
7896}
7897
7898impl io::Read for MultiBufferBytes<'_> {
7899    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7900        let len = cmp::min(buf.len(), self.chunk.len());
7901        buf[..len].copy_from_slice(&self.chunk[..len]);
7902        if len > 0 {
7903            self.consume(len);
7904        }
7905        Ok(len)
7906    }
7907}
7908
7909impl io::Read for ReversedMultiBufferBytes<'_> {
7910    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7911        let len = cmp::min(buf.len(), self.chunk.len());
7912        buf[..len].copy_from_slice(&self.chunk[..len]);
7913        buf[..len].reverse();
7914        if len > 0 {
7915            self.range.end -= len;
7916            self.chunk = &self.chunk[..self.chunk.len() - len];
7917            if !self.range.is_empty()
7918                && self.chunk.is_empty()
7919                && let Some(chunk) = self.chunks.next()
7920            {
7921                self.chunk = chunk.as_bytes();
7922            }
7923        }
7924        Ok(len)
7925    }
7926}
7927
7928impl<'a> Iterator for ExcerptChunks<'a> {
7929    type Item = Chunk<'a>;
7930
7931    fn next(&mut self) -> Option<Self::Item> {
7932        if let Some(chunk) = self.content_chunks.next() {
7933            return Some(chunk);
7934        }
7935
7936        if self.footer_height > 0 {
7937            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7938            let chars = (1 << self.footer_height) - 1;
7939            self.footer_height = 0;
7940            return Some(Chunk {
7941                text,
7942                chars,
7943                ..Default::default()
7944            });
7945        }
7946
7947        None
7948    }
7949}
7950
7951impl ToOffset for Point {
7952    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7953        snapshot.point_to_offset(*self)
7954    }
7955}
7956
7957impl ToOffset for usize {
7958    #[track_caller]
7959    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7960        assert!(
7961            *self <= snapshot.len(),
7962            "offset {} is greater than the snapshot.len() {}",
7963            *self,
7964            snapshot.len(),
7965        );
7966        *self
7967    }
7968}
7969
7970impl ToOffset for OffsetUtf16 {
7971    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7972        snapshot.offset_utf16_to_offset(*self)
7973    }
7974}
7975
7976impl ToOffset for PointUtf16 {
7977    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7978        snapshot.point_utf16_to_offset(*self)
7979    }
7980}
7981
7982impl ToOffsetUtf16 for OffsetUtf16 {
7983    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7984        *self
7985    }
7986}
7987
7988impl ToOffsetUtf16 for usize {
7989    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7990        snapshot.offset_to_offset_utf16(*self)
7991    }
7992}
7993
7994impl ToPoint for usize {
7995    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7996        snapshot.offset_to_point(*self)
7997    }
7998}
7999
8000impl ToPoint for Point {
8001    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8002        *self
8003    }
8004}
8005
8006impl ToPointUtf16 for usize {
8007    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8008        snapshot.offset_to_point_utf16(*self)
8009    }
8010}
8011
8012impl ToPointUtf16 for Point {
8013    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8014        snapshot.point_to_point_utf16(*self)
8015    }
8016}
8017
8018impl ToPointUtf16 for PointUtf16 {
8019    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8020        *self
8021    }
8022}
8023
8024impl From<ExcerptId> for EntityId {
8025    fn from(id: ExcerptId) -> Self {
8026        EntityId::from(id.0 as u64)
8027    }
8028}
8029
8030#[cfg(debug_assertions)]
8031pub mod debug {
8032    use super::*;
8033
8034    pub trait ToMultiBufferDebugRanges {
8035        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
8036        -> Vec<Range<usize>>;
8037    }
8038
8039    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8040        fn to_multi_buffer_debug_ranges(
8041            &self,
8042            snapshot: &MultiBufferSnapshot,
8043        ) -> Vec<Range<usize>> {
8044            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8045        }
8046    }
8047
8048    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8049        fn to_multi_buffer_debug_ranges(
8050            &self,
8051            snapshot: &MultiBufferSnapshot,
8052        ) -> Vec<Range<usize>> {
8053            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8054                .to_multi_buffer_debug_ranges(snapshot)
8055        }
8056    }
8057
8058    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8059        fn to_multi_buffer_debug_ranges(
8060            &self,
8061            snapshot: &MultiBufferSnapshot,
8062        ) -> Vec<Range<usize>> {
8063            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8064        }
8065    }
8066
8067    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8068        fn to_multi_buffer_debug_ranges(
8069            &self,
8070            snapshot: &MultiBufferSnapshot,
8071        ) -> Vec<Range<usize>> {
8072            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8073        }
8074    }
8075
8076    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8077        fn to_multi_buffer_debug_ranges(
8078            &self,
8079            snapshot: &MultiBufferSnapshot,
8080        ) -> Vec<Range<usize>> {
8081            self.iter()
8082                .map(|item| {
8083                    let offset = item.to_offset(snapshot);
8084                    offset..offset
8085                })
8086                .collect()
8087        }
8088    }
8089
8090    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8091        fn to_multi_buffer_debug_ranges(
8092            &self,
8093            snapshot: &MultiBufferSnapshot,
8094        ) -> Vec<Range<usize>> {
8095            self.iter()
8096                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8097                .collect()
8098        }
8099    }
8100}