multi_buffer.rs

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