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