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            return Some(
 739                self.buffers
 740                    .borrow()
 741                    .values()
 742                    .next()
 743                    .unwrap()
 744                    .buffer
 745                    .clone(),
 746            );
 747        } else {
 748            None
 749        }
 750    }
 751
 752    pub fn is_singleton(&self) -> bool {
 753        self.singleton
 754    }
 755
 756    pub fn subscribe(&mut self) -> Subscription {
 757        self.subscriptions.subscribe()
 758    }
 759
 760    pub fn is_dirty(&self, cx: &App) -> bool {
 761        self.read(cx).is_dirty()
 762    }
 763
 764    pub fn has_deleted_file(&self, cx: &App) -> bool {
 765        self.read(cx).has_deleted_file()
 766    }
 767
 768    pub fn has_conflict(&self, cx: &App) -> bool {
 769        self.read(cx).has_conflict()
 770    }
 771
 772    // The `is_empty` signature doesn't match what clippy expects
 773    #[allow(clippy::len_without_is_empty)]
 774    pub fn len(&self, cx: &App) -> usize {
 775        self.read(cx).len()
 776    }
 777
 778    pub fn is_empty(&self) -> bool {
 779        self.buffers.borrow().is_empty()
 780    }
 781
 782    pub fn symbols_containing<T: ToOffset>(
 783        &self,
 784        offset: T,
 785        theme: Option<&SyntaxTheme>,
 786        cx: &App,
 787    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 788        self.read(cx).symbols_containing(offset, theme)
 789    }
 790
 791    pub fn edit<I, S, T>(
 792        &self,
 793        edits: I,
 794        autoindent_mode: Option<AutoindentMode>,
 795        cx: &mut Context<Self>,
 796    ) where
 797        I: IntoIterator<Item = (Range<S>, T)>,
 798        S: ToOffset,
 799        T: Into<Arc<str>>,
 800    {
 801        let snapshot = self.read(cx);
 802        let edits = edits
 803            .into_iter()
 804            .map(|(range, new_text)| {
 805                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 806                if range.start > range.end {
 807                    mem::swap(&mut range.start, &mut range.end);
 808                }
 809                (range, new_text.into())
 810            })
 811            .collect::<Vec<_>>();
 812
 813        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 814
 815        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 816        fn edit_internal(
 817            this: &MultiBuffer,
 818            snapshot: Ref<MultiBufferSnapshot>,
 819            edits: Vec<(Range<usize>, Arc<str>)>,
 820            mut autoindent_mode: Option<AutoindentMode>,
 821            cx: &mut Context<MultiBuffer>,
 822        ) {
 823            if this.read_only() || this.buffers.borrow().is_empty() {
 824                return;
 825            }
 826
 827            let original_indent_columns = match &mut autoindent_mode {
 828                Some(AutoindentMode::Block {
 829                    original_indent_columns,
 830                }) => mem::take(original_indent_columns),
 831                _ => Default::default(),
 832            };
 833
 834            let (buffer_edits, edited_excerpt_ids) =
 835                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 836            drop(snapshot);
 837
 838            let mut buffer_ids = Vec::new();
 839            for (buffer_id, mut edits) in buffer_edits {
 840                buffer_ids.push(buffer_id);
 841                edits.sort_by_key(|edit| edit.range.start);
 842                this.buffers.borrow()[&buffer_id]
 843                    .buffer
 844                    .update(cx, |buffer, cx| {
 845                        let mut edits = edits.into_iter().peekable();
 846                        let mut insertions = Vec::new();
 847                        let mut original_indent_columns = Vec::new();
 848                        let mut deletions = Vec::new();
 849                        let empty_str: Arc<str> = Arc::default();
 850                        while let Some(BufferEdit {
 851                            mut range,
 852                            mut new_text,
 853                            mut is_insertion,
 854                            original_indent_column,
 855                            excerpt_id,
 856                        }) = edits.next()
 857                        {
 858                            while let Some(BufferEdit {
 859                                range: next_range,
 860                                is_insertion: next_is_insertion,
 861                                new_text: next_new_text,
 862                                excerpt_id: next_excerpt_id,
 863                                ..
 864                            }) = edits.peek()
 865                            {
 866                                if range.end >= next_range.start {
 867                                    range.end = cmp::max(next_range.end, range.end);
 868                                    is_insertion |= *next_is_insertion;
 869                                    if excerpt_id == *next_excerpt_id {
 870                                        new_text = format!("{new_text}{next_new_text}").into();
 871                                    }
 872                                    edits.next();
 873                                } else {
 874                                    break;
 875                                }
 876                            }
 877
 878                            if is_insertion {
 879                                original_indent_columns.push(original_indent_column);
 880                                insertions.push((
 881                                    buffer.anchor_before(range.start)
 882                                        ..buffer.anchor_before(range.end),
 883                                    new_text.clone(),
 884                                ));
 885                            } else if !range.is_empty() {
 886                                deletions.push((
 887                                    buffer.anchor_before(range.start)
 888                                        ..buffer.anchor_before(range.end),
 889                                    empty_str.clone(),
 890                                ));
 891                            }
 892                        }
 893
 894                        let deletion_autoindent_mode =
 895                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 896                                Some(AutoindentMode::Block {
 897                                    original_indent_columns: Default::default(),
 898                                })
 899                            } else {
 900                                autoindent_mode.clone()
 901                            };
 902                        let insertion_autoindent_mode =
 903                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 904                                Some(AutoindentMode::Block {
 905                                    original_indent_columns,
 906                                })
 907                            } else {
 908                                autoindent_mode.clone()
 909                            };
 910
 911                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 912                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 913                    })
 914            }
 915
 916            cx.emit(Event::ExcerptsEdited {
 917                excerpt_ids: edited_excerpt_ids,
 918                buffer_ids,
 919            });
 920        }
 921    }
 922
 923    fn convert_edits_to_buffer_edits(
 924        &self,
 925        edits: Vec<(Range<usize>, Arc<str>)>,
 926        snapshot: &MultiBufferSnapshot,
 927        original_indent_columns: &[Option<u32>],
 928    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 929        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 930        let mut edited_excerpt_ids = Vec::new();
 931        let mut cursor = snapshot.cursor::<usize>();
 932        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 933            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 934
 935            cursor.seek(&range.start);
 936            let mut start_region = cursor.region().expect("start offset out of bounds");
 937            if !start_region.is_main_buffer {
 938                cursor.next();
 939                if let Some(region) = cursor.region() {
 940                    start_region = region;
 941                } else {
 942                    continue;
 943                }
 944            }
 945
 946            if range.end < start_region.range.start {
 947                continue;
 948            }
 949
 950            if range.end > start_region.range.end {
 951                cursor.seek_forward(&range.end);
 952            }
 953            let mut end_region = cursor.region().expect("end offset out of bounds");
 954            if !end_region.is_main_buffer {
 955                cursor.prev();
 956                if let Some(region) = cursor.region() {
 957                    end_region = region;
 958                } else {
 959                    continue;
 960                }
 961            }
 962
 963            if range.start > end_region.range.end {
 964                continue;
 965            }
 966
 967            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 968            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 969            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 970                .min(start_region.buffer_range.end);
 971            let buffer_end =
 972                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 973
 974            if start_region.excerpt.id == end_region.excerpt.id {
 975                if start_region.is_main_buffer {
 976                    edited_excerpt_ids.push(start_region.excerpt.id);
 977                    buffer_edits
 978                        .entry(start_region.buffer.remote_id())
 979                        .or_default()
 980                        .push(BufferEdit {
 981                            range: buffer_start..buffer_end,
 982                            new_text,
 983                            is_insertion: true,
 984                            original_indent_column,
 985                            excerpt_id: start_region.excerpt.id,
 986                        });
 987                }
 988            } else {
 989                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 990                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 991                if start_region.is_main_buffer {
 992                    edited_excerpt_ids.push(start_region.excerpt.id);
 993                    buffer_edits
 994                        .entry(start_region.buffer.remote_id())
 995                        .or_default()
 996                        .push(BufferEdit {
 997                            range: start_excerpt_range,
 998                            new_text: new_text.clone(),
 999                            is_insertion: true,
1000                            original_indent_column,
1001                            excerpt_id: start_region.excerpt.id,
1002                        });
1003                }
1004                if end_region.is_main_buffer {
1005                    edited_excerpt_ids.push(end_region.excerpt.id);
1006                    buffer_edits
1007                        .entry(end_region.buffer.remote_id())
1008                        .or_default()
1009                        .push(BufferEdit {
1010                            range: end_excerpt_range,
1011                            new_text: new_text.clone(),
1012                            is_insertion: false,
1013                            original_indent_column,
1014                            excerpt_id: end_region.excerpt.id,
1015                        });
1016                }
1017
1018                cursor.seek(&range.start);
1019                cursor.next_excerpt();
1020                while let Some(region) = cursor.region() {
1021                    if region.excerpt.id == end_region.excerpt.id {
1022                        break;
1023                    }
1024                    if region.is_main_buffer {
1025                        edited_excerpt_ids.push(region.excerpt.id);
1026                        buffer_edits
1027                            .entry(region.buffer.remote_id())
1028                            .or_default()
1029                            .push(BufferEdit {
1030                                range: region.buffer_range,
1031                                new_text: new_text.clone(),
1032                                is_insertion: false,
1033                                original_indent_column,
1034                                excerpt_id: region.excerpt.id,
1035                            });
1036                    }
1037                    cursor.next_excerpt();
1038                }
1039            }
1040        }
1041        (buffer_edits, edited_excerpt_ids)
1042    }
1043
1044    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1045    where
1046        I: IntoIterator<Item = Range<S>>,
1047        S: ToOffset,
1048    {
1049        let snapshot = self.read(cx);
1050        let empty = Arc::<str>::from("");
1051        let edits = ranges
1052            .into_iter()
1053            .map(|range| {
1054                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1055                if range.start > range.end {
1056                    mem::swap(&mut range.start, &mut range.end);
1057                }
1058                (range, empty.clone())
1059            })
1060            .collect::<Vec<_>>();
1061
1062        return autoindent_ranges_internal(self, snapshot, edits, cx);
1063
1064        fn autoindent_ranges_internal(
1065            this: &MultiBuffer,
1066            snapshot: Ref<MultiBufferSnapshot>,
1067            edits: Vec<(Range<usize>, Arc<str>)>,
1068            cx: &mut Context<MultiBuffer>,
1069        ) {
1070            if this.read_only() || this.buffers.borrow().is_empty() {
1071                return;
1072            }
1073
1074            let (buffer_edits, edited_excerpt_ids) =
1075                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1076            drop(snapshot);
1077
1078            let mut buffer_ids = Vec::new();
1079            for (buffer_id, mut edits) in buffer_edits {
1080                buffer_ids.push(buffer_id);
1081                edits.sort_unstable_by_key(|edit| edit.range.start);
1082
1083                let mut ranges: Vec<Range<usize>> = Vec::new();
1084                for edit in edits {
1085                    if let Some(last_range) = ranges.last_mut()
1086                        && 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    // If point is at the end of the buffer, the last excerpt is returned
2200    pub fn point_to_buffer_offset<T: ToOffset>(
2201        &self,
2202        point: T,
2203        cx: &App,
2204    ) -> Option<(Entity<Buffer>, usize)> {
2205        let snapshot = self.read(cx);
2206        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2207        Some((
2208            self.buffers
2209                .borrow()
2210                .get(&buffer.remote_id())?
2211                .buffer
2212                .clone(),
2213            offset,
2214        ))
2215    }
2216
2217    // If point is at the end of the buffer, the last excerpt is returned
2218    pub fn point_to_buffer_point<T: ToPoint>(
2219        &self,
2220        point: T,
2221        cx: &App,
2222    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2223        let snapshot = self.read(cx);
2224        let (buffer, point, is_main_buffer) =
2225            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2226        Some((
2227            self.buffers
2228                .borrow()
2229                .get(&buffer.remote_id())?
2230                .buffer
2231                .clone(),
2232            point,
2233            is_main_buffer,
2234        ))
2235    }
2236
2237    pub fn buffer_point_to_anchor(
2238        &self,
2239        buffer: &Entity<Buffer>,
2240        point: Point,
2241        cx: &App,
2242    ) -> Option<Anchor> {
2243        let mut found = None;
2244        let snapshot = buffer.read(cx).snapshot();
2245        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2246            let start = range.context.start.to_point(&snapshot);
2247            let end = range.context.end.to_point(&snapshot);
2248            if start <= point && point < end {
2249                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2250                break;
2251            }
2252            if point < start {
2253                found = Some((start, excerpt_id));
2254            }
2255            if point > end {
2256                found = Some((end, excerpt_id));
2257            }
2258        }
2259
2260        found.map(|(point, excerpt_id)| {
2261            let text_anchor = snapshot.anchor_after(point);
2262            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2263        })
2264    }
2265
2266    pub fn remove_excerpts(
2267        &mut self,
2268        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2269        cx: &mut Context<Self>,
2270    ) {
2271        self.sync(cx);
2272        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2273        if ids.is_empty() {
2274            return;
2275        }
2276
2277        let mut buffers = self.buffers.borrow_mut();
2278        let mut snapshot = self.snapshot.borrow_mut();
2279        let mut new_excerpts = SumTree::default();
2280        let mut cursor = snapshot
2281            .excerpts
2282            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2283        let mut edits = Vec::new();
2284        let mut excerpt_ids = ids.iter().copied().peekable();
2285        let mut removed_buffer_ids = Vec::new();
2286
2287        while let Some(excerpt_id) = excerpt_ids.next() {
2288            self.paths_by_excerpt.remove(&excerpt_id);
2289            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2290            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2291            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), &());
2292
2293            if let Some(mut excerpt) = cursor.item() {
2294                if excerpt.id != excerpt_id {
2295                    continue;
2296                }
2297                let mut old_start = cursor.start().1;
2298
2299                // Skip over the removed excerpt.
2300                'remove_excerpts: loop {
2301                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2302                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2303                        if buffer_state.excerpts.is_empty() {
2304                            log::debug!(
2305                                "removing buffer and diff for buffer {}",
2306                                excerpt.buffer_id
2307                            );
2308                            buffers.remove(&excerpt.buffer_id);
2309                            removed_buffer_ids.push(excerpt.buffer_id);
2310                        }
2311                    }
2312                    cursor.next();
2313
2314                    // Skip over any subsequent excerpts that are also removed.
2315                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2316                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2317                        if let Some(next_excerpt) = cursor.item()
2318                            && next_excerpt.locator == *next_locator
2319                        {
2320                            excerpt_ids.next();
2321                            excerpt = next_excerpt;
2322                            continue 'remove_excerpts;
2323                        }
2324                    }
2325
2326                    break;
2327                }
2328
2329                // When removing the last excerpt, remove the trailing newline from
2330                // the previous excerpt.
2331                if cursor.item().is_none() && old_start.value > 0 {
2332                    old_start.value -= 1;
2333                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2334                }
2335
2336                // Push an edit for the removal of this run of excerpts.
2337                let old_end = cursor.start().1;
2338                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2339                edits.push(Edit {
2340                    old: old_start..old_end,
2341                    new: new_start..new_start,
2342                });
2343            }
2344        }
2345        let suffix = cursor.suffix();
2346        let changed_trailing_excerpt = suffix.is_empty();
2347        new_excerpts.append(suffix, &());
2348        drop(cursor);
2349        snapshot.excerpts = new_excerpts;
2350        for buffer_id in &removed_buffer_ids {
2351            self.diffs.remove(buffer_id);
2352            snapshot.diffs.remove(buffer_id);
2353        }
2354
2355        if changed_trailing_excerpt {
2356            snapshot.trailing_excerpt_update_count += 1;
2357        }
2358
2359        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2360        self.buffer_changed_since_sync.replace(true);
2361        cx.emit(Event::Edited {
2362            singleton_buffer_edited: false,
2363            edited_buffer: None,
2364        });
2365        cx.emit(Event::ExcerptsRemoved {
2366            ids,
2367            removed_buffer_ids,
2368        });
2369        cx.notify();
2370    }
2371
2372    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2373        &self,
2374        anchors: Anchors,
2375        cx: &mut Context<Self>,
2376    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2377        let borrow = self.buffers.borrow();
2378        let mut error = None;
2379        let mut futures = Vec::new();
2380        for anchor in anchors {
2381            if let Some(buffer_id) = anchor.buffer_id {
2382                if let Some(buffer) = borrow.get(&buffer_id) {
2383                    buffer.buffer.update(cx, |buffer, _| {
2384                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2385                    });
2386                } else {
2387                    error = Some(anyhow!(
2388                        "buffer {buffer_id} is not part of this multi-buffer"
2389                    ));
2390                    break;
2391                }
2392            }
2393        }
2394        async move {
2395            if let Some(error) = error {
2396                Err(error)?;
2397            }
2398            for future in futures {
2399                future.await?;
2400            }
2401            Ok(())
2402        }
2403    }
2404
2405    pub fn text_anchor_for_position<T: ToOffset>(
2406        &self,
2407        position: T,
2408        cx: &App,
2409    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2410        let snapshot = self.read(cx);
2411        let anchor = snapshot.anchor_before(position);
2412        let buffer = self
2413            .buffers
2414            .borrow()
2415            .get(&anchor.buffer_id?)?
2416            .buffer
2417            .clone();
2418        Some((buffer, anchor.text_anchor))
2419    }
2420
2421    fn on_buffer_event(
2422        &mut self,
2423        buffer: Entity<Buffer>,
2424        event: &language::BufferEvent,
2425        cx: &mut Context<Self>,
2426    ) {
2427        cx.emit(match event {
2428            language::BufferEvent::Edited => Event::Edited {
2429                singleton_buffer_edited: true,
2430                edited_buffer: Some(buffer),
2431            },
2432            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2433            language::BufferEvent::Saved => Event::Saved,
2434            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2435            language::BufferEvent::Reloaded => Event::Reloaded,
2436            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2437            language::BufferEvent::LanguageChanged => {
2438                Event::LanguageChanged(buffer.read(cx).remote_id())
2439            }
2440            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2441            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2442            language::BufferEvent::Closed => Event::Closed,
2443            language::BufferEvent::Discarded => Event::Discarded,
2444            language::BufferEvent::CapabilityChanged => {
2445                self.capability = buffer.read(cx).capability();
2446                Event::CapabilityChanged
2447            }
2448            language::BufferEvent::Operation { .. } => return,
2449        });
2450    }
2451
2452    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2453        self.sync(cx);
2454        let mut snapshot = self.snapshot.borrow_mut();
2455        let diff = diff.read(cx);
2456        let buffer_id = diff.buffer_id;
2457        let diff = diff.snapshot(cx);
2458        snapshot.diffs.insert(buffer_id, diff);
2459    }
2460
2461    fn buffer_diff_changed(
2462        &mut self,
2463        diff: Entity<BufferDiff>,
2464        range: Range<text::Anchor>,
2465        cx: &mut Context<Self>,
2466    ) {
2467        self.sync(cx);
2468        self.buffer_changed_since_sync.replace(true);
2469
2470        let diff = diff.read(cx);
2471        let buffer_id = diff.buffer_id;
2472        let buffers = self.buffers.borrow();
2473        let Some(buffer_state) = buffers.get(&buffer_id) else {
2474            return;
2475        };
2476
2477        let buffer = buffer_state.buffer.read(cx);
2478        let diff_change_range = range.to_offset(buffer);
2479
2480        let new_diff = diff.snapshot(cx);
2481        let mut snapshot = self.snapshot.borrow_mut();
2482        let base_text_changed = snapshot
2483            .diffs
2484            .get(&buffer_id)
2485            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2486
2487        snapshot.diffs.insert(buffer_id, new_diff);
2488
2489        let mut excerpt_edits = Vec::new();
2490        for locator in &buffer_state.excerpts {
2491            let mut cursor = snapshot
2492                .excerpts
2493                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2494            cursor.seek_forward(&Some(locator), Bias::Left);
2495            if let Some(excerpt) = cursor.item()
2496                && excerpt.locator == *locator
2497            {
2498                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2499                if diff_change_range.end < excerpt_buffer_range.start
2500                    || diff_change_range.start > excerpt_buffer_range.end
2501                {
2502                    continue;
2503                }
2504                let excerpt_start = cursor.start().1;
2505                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2506                let diff_change_start_in_excerpt = ExcerptOffset::new(
2507                    diff_change_range
2508                        .start
2509                        .saturating_sub(excerpt_buffer_range.start),
2510                );
2511                let diff_change_end_in_excerpt = ExcerptOffset::new(
2512                    diff_change_range
2513                        .end
2514                        .saturating_sub(excerpt_buffer_range.start),
2515                );
2516                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2517                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2518                excerpt_edits.push(Edit {
2519                    old: edit_start..edit_end,
2520                    new: edit_start..edit_end,
2521                });
2522            }
2523        }
2524
2525        self.sync_diff_transforms(
2526            &mut snapshot,
2527            excerpt_edits,
2528            DiffChangeKind::DiffUpdated {
2529                base_changed: base_text_changed,
2530            },
2531        );
2532        cx.emit(Event::Edited {
2533            singleton_buffer_edited: false,
2534            edited_buffer: None,
2535        });
2536    }
2537
2538    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2539        self.buffers
2540            .borrow()
2541            .values()
2542            .map(|state| state.buffer.clone())
2543            .collect()
2544    }
2545
2546    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2547        self.buffers
2548            .borrow()
2549            .get(&buffer_id)
2550            .map(|state| state.buffer.clone())
2551    }
2552
2553    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2554        self.point_to_buffer_offset(point, cx)
2555            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2556    }
2557
2558    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2559        let buffer_id = self
2560            .snapshot
2561            .borrow()
2562            .excerpts
2563            .first()
2564            .map(|excerpt| excerpt.buffer.remote_id());
2565        buffer_id
2566            .and_then(|buffer_id| self.buffer(buffer_id))
2567            .map(|buffer| {
2568                let buffer = buffer.read(cx);
2569                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2570            })
2571            .unwrap_or_else(move || self.language_settings_at(0, cx))
2572    }
2573
2574    pub fn language_settings_at<'a, T: ToOffset>(
2575        &'a self,
2576        point: T,
2577        cx: &'a App,
2578    ) -> Cow<'a, LanguageSettings> {
2579        let mut language = None;
2580        let mut file = None;
2581        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2582            let buffer = buffer.read(cx);
2583            language = buffer.language_at(offset);
2584            file = buffer.file();
2585        }
2586        language_settings(language.map(|l| l.name()), file, cx)
2587    }
2588
2589    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2590        self.buffers
2591            .borrow()
2592            .values()
2593            .for_each(|state| f(&state.buffer))
2594    }
2595
2596    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2597        if let Some(title) = self.title.as_ref() {
2598            return title.into();
2599        }
2600
2601        if let Some(buffer) = self.as_singleton() {
2602            let buffer = buffer.read(cx);
2603
2604            if let Some(file) = buffer.file() {
2605                return file.file_name(cx).to_string_lossy();
2606            }
2607
2608            if let Some(title) = self.buffer_content_title(buffer) {
2609                return title;
2610            }
2611        };
2612
2613        "untitled".into()
2614    }
2615
2616    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2617        let mut is_leading_whitespace = true;
2618        let mut count = 0;
2619        let mut prev_was_space = false;
2620        let mut title = String::new();
2621
2622        for ch in buffer.snapshot().chars() {
2623            if is_leading_whitespace && ch.is_whitespace() {
2624                continue;
2625            }
2626
2627            is_leading_whitespace = false;
2628
2629            if ch == '\n' || count >= 40 {
2630                break;
2631            }
2632
2633            if ch.is_whitespace() {
2634                if !prev_was_space {
2635                    title.push(' ');
2636                    count += 1;
2637                    prev_was_space = true;
2638                }
2639            } else {
2640                title.push(ch);
2641                count += 1;
2642                prev_was_space = false;
2643            }
2644        }
2645
2646        let title = title.trim_end().to_string();
2647
2648        if title.is_empty() {
2649            return None;
2650        }
2651
2652        Some(title.into())
2653    }
2654
2655    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2656        self.title = Some(title);
2657        cx.notify();
2658    }
2659
2660    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2661    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2662        for buffer_state in self.buffers.borrow().values() {
2663            buffer_state
2664                .buffer
2665                .update(cx, |buffer, _cx| buffer.refresh_preview());
2666        }
2667    }
2668
2669    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2670    pub fn preserve_preview(&self, cx: &App) -> bool {
2671        self.buffers
2672            .borrow()
2673            .values()
2674            .all(|state| state.buffer.read(cx).preserve_preview())
2675    }
2676
2677    #[cfg(any(test, feature = "test-support"))]
2678    pub fn is_parsing(&self, cx: &App) -> bool {
2679        self.as_singleton().unwrap().read(cx).is_parsing()
2680    }
2681
2682    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2683        let buffer_id = diff.read(cx).buffer_id;
2684        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2685        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2686    }
2687
2688    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2689        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2690    }
2691
2692    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2693        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2694    }
2695
2696    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2697        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2698    }
2699
2700    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2701        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2702        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2703    }
2704
2705    pub fn all_diff_hunks_expanded(&self) -> bool {
2706        self.snapshot.borrow().all_diff_hunks_expanded
2707    }
2708
2709    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2710        self.snapshot.borrow_mut().all_diff_hunks_expanded = false;
2711        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2712    }
2713
2714    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2715        self.read(cx)
2716            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2717            .nth(1)
2718            .is_some()
2719    }
2720
2721    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2722        let snapshot = self.read(cx);
2723        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2724        let offset_range = range.to_offset(&snapshot);
2725        cursor.seek(&offset_range.start, Bias::Left);
2726        while let Some(item) = cursor.item() {
2727            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2728                break;
2729            }
2730            if item.hunk_info().is_some() {
2731                return true;
2732            }
2733            cursor.next();
2734        }
2735        false
2736    }
2737
2738    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2739        let snapshot = self.read(cx);
2740        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2741        for range in ranges {
2742            let range = range.to_point(&snapshot);
2743            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2744            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2745            let start = start.saturating_sub(1);
2746            let end = snapshot.len().min(end + 1);
2747            cursor.seek(&start, Bias::Right);
2748            while let Some(item) = cursor.item() {
2749                if *cursor.start() >= end {
2750                    break;
2751                }
2752                if item.hunk_info().is_some() {
2753                    return true;
2754                }
2755                cursor.next();
2756            }
2757        }
2758        false
2759    }
2760
2761    pub fn expand_or_collapse_diff_hunks_inner(
2762        &mut self,
2763        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2764        expand: bool,
2765        cx: &mut Context<Self>,
2766    ) {
2767        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2768            return;
2769        }
2770        self.sync(cx);
2771        let mut snapshot = self.snapshot.borrow_mut();
2772        let mut excerpt_edits = Vec::new();
2773        let mut last_hunk_row = None;
2774        for (range, end_excerpt_id) in ranges {
2775            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2776                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2777                    continue;
2778                }
2779                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2780                    continue;
2781                }
2782                let start = Anchor::in_buffer(
2783                    diff_hunk.excerpt_id,
2784                    diff_hunk.buffer_id,
2785                    diff_hunk.buffer_range.start,
2786                );
2787                let end = Anchor::in_buffer(
2788                    diff_hunk.excerpt_id,
2789                    diff_hunk.buffer_id,
2790                    diff_hunk.buffer_range.end,
2791                );
2792                let start = snapshot.excerpt_offset_for_anchor(&start);
2793                let end = snapshot.excerpt_offset_for_anchor(&end);
2794                last_hunk_row = Some(diff_hunk.row_range.start);
2795                excerpt_edits.push(text::Edit {
2796                    old: start..end,
2797                    new: start..end,
2798                });
2799            }
2800        }
2801
2802        self.sync_diff_transforms(
2803            &mut snapshot,
2804            excerpt_edits,
2805            DiffChangeKind::ExpandOrCollapseHunks { expand },
2806        );
2807        cx.emit(Event::DiffHunksToggled);
2808        cx.emit(Event::Edited {
2809            singleton_buffer_edited: false,
2810            edited_buffer: None,
2811        });
2812    }
2813
2814    pub fn expand_or_collapse_diff_hunks(
2815        &mut self,
2816        ranges: Vec<Range<Anchor>>,
2817        expand: bool,
2818        cx: &mut Context<Self>,
2819    ) {
2820        let snapshot = self.snapshot.borrow().clone();
2821        let ranges = ranges.iter().map(move |range| {
2822            let end_excerpt_id = range.end.excerpt_id;
2823            let range = range.to_point(&snapshot);
2824            let mut peek_end = range.end;
2825            if range.end.row < snapshot.max_row().0 {
2826                peek_end = Point::new(range.end.row + 1, 0);
2827            };
2828            (range.start..peek_end, end_excerpt_id)
2829        });
2830        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2831    }
2832
2833    pub fn resize_excerpt(
2834        &mut self,
2835        id: ExcerptId,
2836        range: Range<text::Anchor>,
2837        cx: &mut Context<Self>,
2838    ) {
2839        self.sync(cx);
2840
2841        let mut snapshot = self.snapshot.borrow_mut();
2842        let locator = snapshot.excerpt_locator_for_id(id);
2843        let mut new_excerpts = SumTree::default();
2844        let mut cursor = snapshot
2845            .excerpts
2846            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2847        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2848
2849        let prefix = cursor.slice(&Some(locator), Bias::Left);
2850        new_excerpts.append(prefix, &());
2851
2852        let mut excerpt = cursor.item().unwrap().clone();
2853        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2854
2855        excerpt.range.context.start = range.start;
2856        excerpt.range.context.end = range.end;
2857        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2858
2859        excerpt.text_summary = excerpt
2860            .buffer
2861            .text_summary_for_range(excerpt.range.context.clone());
2862
2863        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2864        let old_start_offset = cursor.start().1;
2865        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2866        let edit = Edit {
2867            old: old_start_offset..old_start_offset + old_text_len,
2868            new: new_start_offset..new_start_offset + new_text_len,
2869        };
2870
2871        if let Some(last_edit) = edits.last_mut() {
2872            if last_edit.old.end == edit.old.start {
2873                last_edit.old.end = edit.old.end;
2874                last_edit.new.end = edit.new.end;
2875            } else {
2876                edits.push(edit);
2877            }
2878        } else {
2879            edits.push(edit);
2880        }
2881
2882        new_excerpts.push(excerpt, &());
2883
2884        cursor.next();
2885
2886        new_excerpts.append(cursor.suffix(), &());
2887
2888        drop(cursor);
2889        snapshot.excerpts = new_excerpts;
2890
2891        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2892        cx.emit(Event::Edited {
2893            singleton_buffer_edited: false,
2894            edited_buffer: None,
2895        });
2896        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2897        cx.notify();
2898    }
2899
2900    pub fn expand_excerpts(
2901        &mut self,
2902        ids: impl IntoIterator<Item = ExcerptId>,
2903        line_count: u32,
2904        direction: ExpandExcerptDirection,
2905        cx: &mut Context<Self>,
2906    ) {
2907        if line_count == 0 {
2908            return;
2909        }
2910        self.sync(cx);
2911        if !self.excerpts_by_path.is_empty() {
2912            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2913            return;
2914        }
2915        let mut snapshot = self.snapshot.borrow_mut();
2916
2917        let ids = ids.into_iter().collect::<Vec<_>>();
2918        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2919        let mut new_excerpts = SumTree::default();
2920        let mut cursor = snapshot
2921            .excerpts
2922            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2923        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2924
2925        for locator in &locators {
2926            let prefix = cursor.slice(&Some(locator), Bias::Left);
2927            new_excerpts.append(prefix, &());
2928
2929            let mut excerpt = cursor.item().unwrap().clone();
2930            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2931
2932            let up_line_count = if direction.should_expand_up() {
2933                line_count
2934            } else {
2935                0
2936            };
2937
2938            let start_row = excerpt
2939                .range
2940                .context
2941                .start
2942                .to_point(&excerpt.buffer)
2943                .row
2944                .saturating_sub(up_line_count);
2945            let start_point = Point::new(start_row, 0);
2946            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2947
2948            let down_line_count = if direction.should_expand_down() {
2949                line_count
2950            } else {
2951                0
2952            };
2953
2954            let mut end_point = excerpt.buffer.clip_point(
2955                excerpt.range.context.end.to_point(&excerpt.buffer)
2956                    + Point::new(down_line_count, 0),
2957                Bias::Left,
2958            );
2959            end_point.column = excerpt.buffer.line_len(end_point.row);
2960            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2961            excerpt.max_buffer_row = end_point.row;
2962
2963            excerpt.text_summary = excerpt
2964                .buffer
2965                .text_summary_for_range(excerpt.range.context.clone());
2966
2967            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2968            let old_start_offset = cursor.start().1;
2969            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2970            let edit = Edit {
2971                old: old_start_offset..old_start_offset + old_text_len,
2972                new: new_start_offset..new_start_offset + new_text_len,
2973            };
2974
2975            if let Some(last_edit) = edits.last_mut() {
2976                if last_edit.old.end == edit.old.start {
2977                    last_edit.old.end = edit.old.end;
2978                    last_edit.new.end = edit.new.end;
2979                } else {
2980                    edits.push(edit);
2981                }
2982            } else {
2983                edits.push(edit);
2984            }
2985
2986            new_excerpts.push(excerpt, &());
2987
2988            cursor.next();
2989        }
2990
2991        new_excerpts.append(cursor.suffix(), &());
2992
2993        drop(cursor);
2994        snapshot.excerpts = new_excerpts;
2995
2996        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2997        cx.emit(Event::Edited {
2998            singleton_buffer_edited: false,
2999            edited_buffer: None,
3000        });
3001        cx.emit(Event::ExcerptsExpanded { ids });
3002        cx.notify();
3003    }
3004
3005    fn sync(&self, cx: &App) {
3006        let changed = self.buffer_changed_since_sync.replace(false);
3007        if !changed {
3008            return;
3009        }
3010
3011        let mut snapshot = self.snapshot.borrow_mut();
3012        let mut excerpts_to_edit = Vec::new();
3013        let mut non_text_state_updated = false;
3014        let mut is_dirty = false;
3015        let mut has_deleted_file = false;
3016        let mut has_conflict = false;
3017        let mut edited = false;
3018        let mut buffers = self.buffers.borrow_mut();
3019        for buffer_state in buffers.values_mut() {
3020            let buffer = buffer_state.buffer.read(cx);
3021            let version = buffer.version();
3022            let non_text_state_update_count = buffer.non_text_state_update_count();
3023
3024            let buffer_edited = version.changed_since(&buffer_state.last_version);
3025            let buffer_non_text_state_updated =
3026                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
3027            if buffer_edited || buffer_non_text_state_updated {
3028                buffer_state.last_version = version;
3029                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
3030                excerpts_to_edit.extend(
3031                    buffer_state
3032                        .excerpts
3033                        .iter()
3034                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3035                );
3036            }
3037
3038            edited |= buffer_edited;
3039            non_text_state_updated |= buffer_non_text_state_updated;
3040            is_dirty |= buffer.is_dirty();
3041            has_deleted_file |= buffer
3042                .file()
3043                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3044            has_conflict |= buffer.has_conflict();
3045        }
3046        if edited {
3047            snapshot.edit_count += 1;
3048        }
3049        if non_text_state_updated {
3050            snapshot.non_text_state_update_count += 1;
3051        }
3052        snapshot.is_dirty = is_dirty;
3053        snapshot.has_deleted_file = has_deleted_file;
3054        snapshot.has_conflict = has_conflict;
3055
3056        for (id, diff) in self.diffs.iter() {
3057            if snapshot.diffs.get(id).is_none() {
3058                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3059            }
3060        }
3061
3062        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3063
3064        let mut edits = Vec::new();
3065        let mut new_excerpts = SumTree::default();
3066        let mut cursor = snapshot
3067            .excerpts
3068            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
3069
3070        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3071            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), &());
3072            let old_excerpt = cursor.item().unwrap();
3073            let buffer = buffer.read(cx);
3074            let buffer_id = buffer.remote_id();
3075
3076            let mut new_excerpt;
3077            if buffer_edited {
3078                edits.extend(
3079                    buffer
3080                        .edits_since_in_range::<usize>(
3081                            old_excerpt.buffer.version(),
3082                            old_excerpt.range.context.clone(),
3083                        )
3084                        .map(|edit| {
3085                            let excerpt_old_start = cursor.start().1;
3086                            let excerpt_new_start =
3087                                ExcerptOffset::new(new_excerpts.summary().text.len);
3088                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3089                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3090                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3091                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3092                            Edit {
3093                                old: old_start..old_end,
3094                                new: new_start..new_end,
3095                            }
3096                        }),
3097                );
3098
3099                new_excerpt = Excerpt::new(
3100                    old_excerpt.id,
3101                    locator.clone(),
3102                    buffer_id,
3103                    buffer.snapshot(),
3104                    old_excerpt.range.clone(),
3105                    old_excerpt.has_trailing_newline,
3106                );
3107            } else {
3108                new_excerpt = old_excerpt.clone();
3109                new_excerpt.buffer = buffer.snapshot();
3110            }
3111
3112            new_excerpts.push(new_excerpt, &());
3113            cursor.next();
3114        }
3115        new_excerpts.append(cursor.suffix(), &());
3116
3117        drop(cursor);
3118        snapshot.excerpts = new_excerpts;
3119
3120        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3121    }
3122
3123    fn sync_diff_transforms(
3124        &self,
3125        snapshot: &mut MultiBufferSnapshot,
3126        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3127        change_kind: DiffChangeKind,
3128    ) {
3129        if excerpt_edits.is_empty() {
3130            return;
3131        }
3132
3133        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3134        let mut old_diff_transforms = snapshot
3135            .diff_transforms
3136            .cursor::<Dimensions<ExcerptOffset, usize>>(&());
3137        let mut new_diff_transforms = SumTree::default();
3138        let mut old_expanded_hunks = HashSet::default();
3139        let mut output_edits = Vec::new();
3140        let mut output_delta = 0_isize;
3141        let mut at_transform_boundary = true;
3142        let mut end_of_current_insert = None;
3143
3144        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3145        while let Some(edit) = excerpt_edits.next() {
3146            excerpts.seek_forward(&edit.new.start, Bias::Right);
3147            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3148                excerpts.prev();
3149            }
3150
3151            // Keep any transforms that are before the edit.
3152            if at_transform_boundary {
3153                at_transform_boundary = false;
3154                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3155                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3156                if let Some(transform) = old_diff_transforms.item()
3157                    && old_diff_transforms.end().0 == edit.old.start
3158                    && old_diff_transforms.start().0 < edit.old.start
3159                {
3160                    self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3161                    old_diff_transforms.next();
3162                }
3163            }
3164
3165            // Compute the start of the edit in output coordinates.
3166            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3167            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3168            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3169
3170            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3171                &edit,
3172                &mut excerpts,
3173                &mut old_diff_transforms,
3174                &mut new_diff_transforms,
3175                &mut end_of_current_insert,
3176                &mut old_expanded_hunks,
3177                snapshot,
3178                change_kind,
3179            );
3180
3181            // Compute the end of the edit in output coordinates.
3182            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3183            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3184            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3185            let edit_new_end =
3186                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3187            let output_edit = Edit {
3188                old: edit_old_start..edit_old_end,
3189                new: edit_new_start..edit_new_end,
3190            };
3191
3192            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3193            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3194            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3195                output_edits.push(output_edit);
3196            }
3197
3198            // If this is the last edit that intersects the current diff transform,
3199            // then recreate the content up to the end of this transform, to prepare
3200            // for reusing additional slices of the old transforms.
3201            if excerpt_edits
3202                .peek()
3203                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3204            {
3205                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3206                    && match old_diff_transforms.item() {
3207                        Some(DiffTransform::BufferContent {
3208                            inserted_hunk_info: Some(hunk),
3209                            ..
3210                        }) => excerpts.item().is_some_and(|excerpt| {
3211                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3212                        }),
3213                        _ => true,
3214                    };
3215
3216                let mut excerpt_offset = edit.new.end;
3217                if !keep_next_old_transform {
3218                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3219                    old_diff_transforms.next();
3220                }
3221
3222                old_expanded_hunks.clear();
3223                self.push_buffer_content_transform(
3224                    snapshot,
3225                    &mut new_diff_transforms,
3226                    excerpt_offset,
3227                    end_of_current_insert,
3228                );
3229                at_transform_boundary = true;
3230            }
3231        }
3232
3233        // Keep any transforms that are after the last edit.
3234        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3235
3236        // Ensure there's always at least one buffer content transform.
3237        if new_diff_transforms.is_empty() {
3238            new_diff_transforms.push(
3239                DiffTransform::BufferContent {
3240                    summary: Default::default(),
3241                    inserted_hunk_info: None,
3242                },
3243                &(),
3244            );
3245        }
3246
3247        self.subscriptions.publish(output_edits);
3248        drop(old_diff_transforms);
3249        drop(excerpts);
3250        snapshot.diff_transforms = new_diff_transforms;
3251        snapshot.edit_count += 1;
3252
3253        #[cfg(any(test, feature = "test-support"))]
3254        snapshot.check_invariants();
3255    }
3256
3257    fn recompute_diff_transforms_for_edit(
3258        &self,
3259        edit: &Edit<TypedOffset<Excerpt>>,
3260        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3261        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
3262        new_diff_transforms: &mut SumTree<DiffTransform>,
3263        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3264        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3265        snapshot: &MultiBufferSnapshot,
3266        change_kind: DiffChangeKind,
3267    ) -> bool {
3268        log::trace!(
3269            "recomputing diff transform for edit {:?} => {:?}",
3270            edit.old.start.value..edit.old.end.value,
3271            edit.new.start.value..edit.new.end.value
3272        );
3273
3274        // Record which hunks were previously expanded.
3275        while let Some(item) = old_diff_transforms.item() {
3276            if let Some(hunk_info) = item.hunk_info() {
3277                log::trace!(
3278                    "previously expanded hunk at {}",
3279                    old_diff_transforms.start().0
3280                );
3281                old_expanded_hunks.insert(hunk_info);
3282            }
3283            if old_diff_transforms.end().0 > edit.old.end {
3284                break;
3285            }
3286            old_diff_transforms.next();
3287        }
3288
3289        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3290        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3291        if old_expanded_hunks.is_empty()
3292            && change_kind == DiffChangeKind::BufferEdited
3293            && !all_diff_hunks_expanded
3294        {
3295            return false;
3296        }
3297
3298        // Visit each excerpt that intersects the edit.
3299        let mut did_expand_hunks = false;
3300        while let Some(excerpt) = excerpts.item() {
3301            // Recompute the expanded hunks in the portion of the excerpt that
3302            // intersects the edit.
3303            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3304                let buffer = &excerpt.buffer;
3305                let excerpt_start = *excerpts.start();
3306                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3307                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3308                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3309                let edit_buffer_start =
3310                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3311                let edit_buffer_end =
3312                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3313                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3314                let edit_anchor_range =
3315                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3316
3317                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3318                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3319                        continue;
3320                    }
3321
3322                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3323                    if hunk_buffer_range.start < excerpt_buffer_start {
3324                        log::trace!("skipping hunk that starts before excerpt");
3325                        continue;
3326                    }
3327
3328                    let hunk_info = DiffTransformHunkInfo {
3329                        excerpt_id: excerpt.id,
3330                        hunk_start_anchor: hunk.buffer_range.start,
3331                        hunk_secondary_status: hunk.secondary_status,
3332                    };
3333
3334                    let hunk_excerpt_start = excerpt_start
3335                        + ExcerptOffset::new(
3336                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3337                        );
3338                    let hunk_excerpt_end = excerpt_end.min(
3339                        excerpt_start
3340                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3341                    );
3342
3343                    self.push_buffer_content_transform(
3344                        snapshot,
3345                        new_diff_transforms,
3346                        hunk_excerpt_start,
3347                        *end_of_current_insert,
3348                    );
3349
3350                    // For every existing hunk, determine if it was previously expanded
3351                    // and if it should currently be expanded.
3352                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3353                    let should_expand_hunk = match &change_kind {
3354                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3355                            was_previously_expanded || all_diff_hunks_expanded
3356                        }
3357                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3358                            let intersects = hunk_buffer_range.is_empty()
3359                                || hunk_buffer_range.end > edit_buffer_start;
3360                            if *expand {
3361                                intersects || was_previously_expanded || all_diff_hunks_expanded
3362                            } else {
3363                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3364                            }
3365                        }
3366                        _ => was_previously_expanded || all_diff_hunks_expanded,
3367                    };
3368
3369                    if should_expand_hunk {
3370                        did_expand_hunks = true;
3371                        log::trace!(
3372                            "expanding hunk {:?}, excerpt:{:?}",
3373                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3374                            excerpt.id
3375                        );
3376
3377                        if !hunk.diff_base_byte_range.is_empty()
3378                            && hunk_buffer_range.start >= edit_buffer_start
3379                            && hunk_buffer_range.start <= excerpt_buffer_end
3380                        {
3381                            let base_text = diff.base_text();
3382                            let mut text_cursor =
3383                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3384                            let mut base_text_summary =
3385                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3386
3387                            let mut has_trailing_newline = false;
3388                            if base_text_summary.last_line_chars > 0 {
3389                                base_text_summary += TextSummary::newline();
3390                                has_trailing_newline = true;
3391                            }
3392
3393                            new_diff_transforms.push(
3394                                DiffTransform::DeletedHunk {
3395                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3396                                    summary: base_text_summary,
3397                                    buffer_id: excerpt.buffer_id,
3398                                    hunk_info,
3399                                    has_trailing_newline,
3400                                },
3401                                &(),
3402                            );
3403                        }
3404
3405                        if !hunk_buffer_range.is_empty() {
3406                            *end_of_current_insert =
3407                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3408                        }
3409                    }
3410                }
3411            }
3412
3413            if excerpts.end() <= edit.new.end {
3414                excerpts.next();
3415            } else {
3416                break;
3417            }
3418        }
3419
3420        did_expand_hunks || !old_expanded_hunks.is_empty()
3421    }
3422
3423    fn append_diff_transforms(
3424        &self,
3425        new_transforms: &mut SumTree<DiffTransform>,
3426        subtree: SumTree<DiffTransform>,
3427    ) {
3428        if let Some(DiffTransform::BufferContent {
3429            inserted_hunk_info,
3430            summary,
3431        }) = subtree.first()
3432            && self.extend_last_buffer_content_transform(
3433                new_transforms,
3434                *inserted_hunk_info,
3435                *summary,
3436            )
3437        {
3438            let mut cursor = subtree.cursor::<()>(&());
3439            cursor.next();
3440            cursor.next();
3441            new_transforms.append(cursor.suffix(), &());
3442            return;
3443        }
3444        new_transforms.append(subtree, &());
3445    }
3446
3447    fn push_diff_transform(
3448        &self,
3449        new_transforms: &mut SumTree<DiffTransform>,
3450        transform: DiffTransform,
3451    ) {
3452        if let DiffTransform::BufferContent {
3453            inserted_hunk_info: inserted_hunk_anchor,
3454            summary,
3455        } = transform
3456            && self.extend_last_buffer_content_transform(
3457                new_transforms,
3458                inserted_hunk_anchor,
3459                summary,
3460            )
3461        {
3462            return;
3463        }
3464        new_transforms.push(transform, &());
3465    }
3466
3467    fn push_buffer_content_transform(
3468        &self,
3469        old_snapshot: &MultiBufferSnapshot,
3470        new_transforms: &mut SumTree<DiffTransform>,
3471        end_offset: ExcerptOffset,
3472        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3473    ) {
3474        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3475            (end_offset.min(insertion_end_offset), Some(hunk_info))
3476        });
3477        let unchanged_region = [(end_offset, None)];
3478
3479        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3480        {
3481            let start_offset = new_transforms.summary().excerpt_len();
3482            if end_offset <= start_offset {
3483                continue;
3484            }
3485            let summary_to_add = old_snapshot
3486                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3487
3488            if !self.extend_last_buffer_content_transform(
3489                new_transforms,
3490                inserted_hunk_info,
3491                summary_to_add,
3492            ) {
3493                new_transforms.push(
3494                    DiffTransform::BufferContent {
3495                        summary: summary_to_add,
3496                        inserted_hunk_info,
3497                    },
3498                    &(),
3499                )
3500            }
3501        }
3502    }
3503
3504    fn extend_last_buffer_content_transform(
3505        &self,
3506        new_transforms: &mut SumTree<DiffTransform>,
3507        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3508        summary_to_add: TextSummary,
3509    ) -> bool {
3510        let mut did_extend = false;
3511        new_transforms.update_last(
3512            |last_transform| {
3513                if let DiffTransform::BufferContent {
3514                    summary,
3515                    inserted_hunk_info: inserted_hunk_anchor,
3516                } = last_transform
3517                    && *inserted_hunk_anchor == new_inserted_hunk_info
3518                {
3519                    *summary += summary_to_add;
3520                    did_extend = true;
3521                }
3522            },
3523            &(),
3524        );
3525        did_extend
3526    }
3527}
3528
3529fn build_excerpt_ranges(
3530    ranges: impl IntoIterator<Item = Range<Point>>,
3531    context_line_count: u32,
3532    buffer_snapshot: &BufferSnapshot,
3533) -> Vec<ExcerptRange<Point>> {
3534    ranges
3535        .into_iter()
3536        .map(|range| {
3537            let start_row = range.start.row.saturating_sub(context_line_count);
3538            let start = Point::new(start_row, 0);
3539            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3540            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3541            ExcerptRange {
3542                context: start..end,
3543                primary: range,
3544            }
3545        })
3546        .collect()
3547}
3548
3549#[cfg(any(test, feature = "test-support"))]
3550impl MultiBuffer {
3551    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3552        let buffer = cx.new(|cx| Buffer::local(text, cx));
3553        cx.new(|cx| Self::singleton(buffer, cx))
3554    }
3555
3556    pub fn build_multi<const COUNT: usize>(
3557        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3558        cx: &mut gpui::App,
3559    ) -> Entity<Self> {
3560        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3561        for (text, ranges) in excerpts {
3562            let buffer = cx.new(|cx| Buffer::local(text, cx));
3563            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3564            multi.update(cx, |multi, cx| {
3565                multi.push_excerpts(buffer, excerpt_ranges, cx)
3566            });
3567        }
3568
3569        multi
3570    }
3571
3572    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3573        cx.new(|cx| Self::singleton(buffer, cx))
3574    }
3575
3576    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3577        cx.new(|cx| {
3578            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3579            let mutation_count = rng.gen_range(1..=5);
3580            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3581            multibuffer
3582        })
3583    }
3584
3585    pub fn randomly_edit(
3586        &mut self,
3587        rng: &mut impl rand::Rng,
3588        edit_count: usize,
3589        cx: &mut Context<Self>,
3590    ) {
3591        use util::RandomCharIter;
3592
3593        let snapshot = self.read(cx);
3594        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3595        let mut last_end = None;
3596        for _ in 0..edit_count {
3597            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3598                break;
3599            }
3600
3601            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3602            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3603            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3604            last_end = Some(end);
3605
3606            let mut range = start..end;
3607            if rng.gen_bool(0.2) {
3608                mem::swap(&mut range.start, &mut range.end);
3609            }
3610
3611            let new_text_len = rng.gen_range(0..10);
3612            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3613
3614            edits.push((range, new_text.into()));
3615        }
3616        log::info!("mutating multi-buffer with {:?}", edits);
3617        drop(snapshot);
3618
3619        self.edit(edits, None, cx);
3620    }
3621
3622    pub fn randomly_edit_excerpts(
3623        &mut self,
3624        rng: &mut impl rand::Rng,
3625        mutation_count: usize,
3626        cx: &mut Context<Self>,
3627    ) {
3628        use rand::prelude::*;
3629        use std::env;
3630        use util::RandomCharIter;
3631
3632        let max_excerpts = env::var("MAX_EXCERPTS")
3633            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3634            .unwrap_or(5);
3635
3636        let mut buffers = Vec::new();
3637        for _ in 0..mutation_count {
3638            if rng.gen_bool(0.05) {
3639                log::info!("Clearing multi-buffer");
3640                self.clear(cx);
3641                continue;
3642            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3643                let ids = self.excerpt_ids();
3644                let mut excerpts = HashSet::default();
3645                for _ in 0..rng.gen_range(0..ids.len()) {
3646                    excerpts.extend(ids.choose(rng).copied());
3647                }
3648
3649                let line_count = rng.gen_range(0..5);
3650
3651                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3652
3653                self.expand_excerpts(
3654                    excerpts.iter().cloned(),
3655                    line_count,
3656                    ExpandExcerptDirection::UpAndDown,
3657                    cx,
3658                );
3659                continue;
3660            }
3661
3662            let excerpt_ids = self.excerpt_ids();
3663            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3664                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3665                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3666                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3667                    let buffer = buffers.last().unwrap().read(cx);
3668                    log::info!(
3669                        "Creating new buffer {} with text: {:?}",
3670                        buffer.remote_id(),
3671                        buffer.text()
3672                    );
3673                    buffers.last().unwrap().clone()
3674                } else {
3675                    self.buffers
3676                        .borrow()
3677                        .values()
3678                        .choose(rng)
3679                        .unwrap()
3680                        .buffer
3681                        .clone()
3682                };
3683
3684                let buffer = buffer_handle.read(cx);
3685                let buffer_text = buffer.text();
3686                let ranges = (0..rng.gen_range(0..5))
3687                    .map(|_| {
3688                        let end_ix =
3689                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3690                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3691                        ExcerptRange::new(start_ix..end_ix)
3692                    })
3693                    .collect::<Vec<_>>();
3694                log::info!(
3695                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3696                    buffer_handle.read(cx).remote_id(),
3697                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3698                    ranges
3699                        .iter()
3700                        .map(|r| &buffer_text[r.context.clone()])
3701                        .collect::<Vec<_>>()
3702                );
3703
3704                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3705                log::info!("Inserted with ids: {:?}", excerpt_id);
3706            } else {
3707                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3708                let mut excerpts_to_remove = excerpt_ids
3709                    .choose_multiple(rng, remove_count)
3710                    .cloned()
3711                    .collect::<Vec<_>>();
3712                let snapshot = self.snapshot.borrow();
3713                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3714                drop(snapshot);
3715                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3716                self.remove_excerpts(excerpts_to_remove, cx);
3717            }
3718        }
3719    }
3720
3721    pub fn randomly_mutate(
3722        &mut self,
3723        rng: &mut impl rand::Rng,
3724        mutation_count: usize,
3725        cx: &mut Context<Self>,
3726    ) {
3727        use rand::prelude::*;
3728
3729        if rng.gen_bool(0.7) || self.singleton {
3730            let buffer = self
3731                .buffers
3732                .borrow()
3733                .values()
3734                .choose(rng)
3735                .map(|state| state.buffer.clone());
3736
3737            if let Some(buffer) = buffer {
3738                buffer.update(cx, |buffer, cx| {
3739                    if rng.r#gen() {
3740                        buffer.randomly_edit(rng, mutation_count, cx);
3741                    } else {
3742                        buffer.randomly_undo_redo(rng, cx);
3743                    }
3744                });
3745            } else {
3746                self.randomly_edit(rng, mutation_count, cx);
3747            }
3748        } else {
3749            self.randomly_edit_excerpts(rng, mutation_count, cx);
3750        }
3751
3752        self.check_invariants(cx);
3753    }
3754
3755    fn check_invariants(&self, cx: &App) {
3756        self.read(cx).check_invariants();
3757    }
3758}
3759
3760impl EventEmitter<Event> for MultiBuffer {}
3761
3762impl MultiBufferSnapshot {
3763    pub fn text(&self) -> String {
3764        self.chunks(0..self.len(), false)
3765            .map(|chunk| chunk.text)
3766            .collect()
3767    }
3768
3769    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3770        self.reversed_chunks_in_range(0..position.to_offset(self))
3771            .flat_map(|c| c.chars().rev())
3772    }
3773
3774    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3775        let mut cursor = self.cursor::<usize>();
3776        cursor.seek(&range.end);
3777        let current_chunks = cursor.region().as_ref().map(|region| {
3778            let start_overshoot = range.start.saturating_sub(region.range.start);
3779            let end_overshoot = range.end - region.range.start;
3780            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3781            let start = region.buffer_range.start + start_overshoot;
3782            region.buffer.reversed_chunks_in_range(start..end)
3783        });
3784        ReversedMultiBufferChunks {
3785            cursor,
3786            current_chunks,
3787            start: range.start,
3788            offset: range.end,
3789        }
3790    }
3791
3792    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3793        let offset = position.to_offset(self);
3794        self.text_for_range(offset..self.len())
3795            .flat_map(|chunk| chunk.chars())
3796    }
3797
3798    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3799        self.chunks(range, false).map(|chunk| chunk.text)
3800    }
3801
3802    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3803        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3804            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3805    }
3806
3807    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3808    where
3809        T: ToOffset,
3810    {
3811        let position = position.to_offset(self);
3812        position == self.clip_offset(position, Bias::Left)
3813            && self
3814                .bytes_in_range(position..self.len())
3815                .flatten()
3816                .copied()
3817                .take(needle.len())
3818                .eq(needle.bytes())
3819    }
3820
3821    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3822        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3823    }
3824
3825    pub fn diff_hunks_in_range<T: ToPoint>(
3826        &self,
3827        range: Range<T>,
3828    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3829        let query_range = range.start.to_point(self)..range.end.to_point(self);
3830        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3831            let diff = self.diffs.get(&buffer.remote_id())?;
3832            let buffer_start = buffer.anchor_before(buffer_range.start);
3833            let buffer_end = buffer.anchor_after(buffer_range.end);
3834            Some(
3835                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3836                    .filter_map(|hunk| {
3837                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3838                            return None;
3839                        }
3840                        Some((hunk.range.clone(), hunk))
3841                    }),
3842            )
3843        })
3844        .filter_map(move |(range, hunk, excerpt)| {
3845            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3846            {
3847                return None;
3848            }
3849            let end_row = if range.end.column == 0 {
3850                range.end.row
3851            } else {
3852                range.end.row + 1
3853            };
3854            Some(MultiBufferDiffHunk {
3855                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3856                buffer_id: excerpt.buffer_id,
3857                excerpt_id: excerpt.id,
3858                buffer_range: hunk.buffer_range.clone(),
3859                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3860                secondary_status: hunk.secondary_status,
3861            })
3862        })
3863    }
3864
3865    pub fn excerpt_ids_for_range<T: ToOffset>(
3866        &self,
3867        range: Range<T>,
3868    ) -> impl Iterator<Item = ExcerptId> + '_ {
3869        let range = range.start.to_offset(self)..range.end.to_offset(self);
3870        let mut cursor = self.cursor::<usize>();
3871        cursor.seek(&range.start);
3872        std::iter::from_fn(move || {
3873            let region = cursor.region()?;
3874            if region.range.start >= range.end {
3875                return None;
3876            }
3877            cursor.next_excerpt();
3878            Some(region.excerpt.id)
3879        })
3880    }
3881
3882    pub fn buffer_ids_for_range<T: ToOffset>(
3883        &self,
3884        range: Range<T>,
3885    ) -> impl Iterator<Item = BufferId> + '_ {
3886        let range = range.start.to_offset(self)..range.end.to_offset(self);
3887        let mut cursor = self.cursor::<usize>();
3888        cursor.seek(&range.start);
3889        std::iter::from_fn(move || {
3890            let region = cursor.region()?;
3891            if region.range.start > range.end
3892                || region.range.start == range.end && region.range.start > range.start
3893            {
3894                return None;
3895            }
3896            cursor.next_excerpt();
3897            Some(region.excerpt.buffer_id)
3898        })
3899    }
3900
3901    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3902        &self,
3903        ranges: impl Iterator<Item = Range<T>>,
3904    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3905        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3906    }
3907
3908    pub fn range_to_buffer_ranges<T: ToOffset>(
3909        &self,
3910        range: Range<T>,
3911    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3912        let start = range.start.to_offset(self);
3913        let end = range.end.to_offset(self);
3914
3915        let mut cursor = self.cursor::<usize>();
3916        cursor.seek(&start);
3917
3918        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3919        while let Some(region) = cursor.region() {
3920            if region.range.start > end {
3921                break;
3922            }
3923            if region.is_main_buffer {
3924                let start_overshoot = start.saturating_sub(region.range.start);
3925                let end_overshoot = end.saturating_sub(region.range.start);
3926                let start = region
3927                    .buffer_range
3928                    .end
3929                    .min(region.buffer_range.start + start_overshoot);
3930                let end = region
3931                    .buffer_range
3932                    .end
3933                    .min(region.buffer_range.start + end_overshoot);
3934                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3935                    *excerpt_id == region.excerpt.id && prev_range.end == start
3936                }) {
3937                    prev.1.end = end;
3938                } else {
3939                    result.push((region.buffer, start..end, region.excerpt.id));
3940                }
3941            }
3942            cursor.next();
3943        }
3944        result
3945    }
3946
3947    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3948        &self,
3949        range: Range<T>,
3950    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3951        let start = range.start.to_offset(self);
3952        let end = range.end.to_offset(self);
3953
3954        let mut cursor = self.cursor::<usize>();
3955        cursor.seek(&start);
3956
3957        std::iter::from_fn(move || {
3958            let region = cursor.region()?;
3959            if region.range.start > end {
3960                return None;
3961            }
3962            let start_overshoot = start.saturating_sub(region.range.start);
3963            let end_overshoot = end.saturating_sub(region.range.start);
3964            let start = region
3965                .buffer_range
3966                .end
3967                .min(region.buffer_range.start + start_overshoot);
3968            let end = region
3969                .buffer_range
3970                .end
3971                .min(region.buffer_range.start + end_overshoot);
3972
3973            let region_excerpt_id = region.excerpt.id;
3974            let deleted_hunk_anchor = if region.is_main_buffer {
3975                None
3976            } else {
3977                Some(self.anchor_before(region.range.start))
3978            };
3979            let result = (
3980                region.buffer,
3981                start..end,
3982                region_excerpt_id,
3983                deleted_hunk_anchor,
3984            );
3985            cursor.next();
3986            Some(result)
3987        })
3988    }
3989
3990    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3991    /// coordinates.
3992    ///
3993    /// The given callback will be called for every excerpt intersecting the given range. It will
3994    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3995    /// The callback should return an iterator of metadata items from that buffer, each paired
3996    /// with a buffer range.
3997    ///
3998    /// The returned iterator yields each of these metadata items, paired with its range in
3999    /// multi-buffer coordinates.
4000    fn lift_buffer_metadata<'a, D, M, I>(
4001        &'a self,
4002        query_range: Range<D>,
4003        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
4004    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
4005    where
4006        I: Iterator<Item = (Range<D>, M)> + 'a,
4007        D: TextDimension + Ord + Sub<D, Output = D>,
4008    {
4009        let max_position = D::from_text_summary(&self.text_summary());
4010        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4011        let mut cursor = self.cursor::<D>();
4012
4013        // Find the excerpt and buffer offset where the given range ends.
4014        cursor.seek(&query_range.end);
4015        let mut range_end = None;
4016        while let Some(region) = cursor.region() {
4017            if region.is_main_buffer {
4018                let mut buffer_end = region.buffer_range.start;
4019                let overshoot = if query_range.end > region.range.start {
4020                    query_range.end - region.range.start
4021                } else {
4022                    D::default()
4023                };
4024                buffer_end.add_assign(&overshoot);
4025                range_end = Some((region.excerpt.id, buffer_end));
4026                break;
4027            }
4028            cursor.next();
4029        }
4030
4031        cursor.seek(&query_range.start);
4032
4033        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4034            && region.range.start > D::zero(&())
4035        {
4036            cursor.prev()
4037        }
4038
4039        iter::from_fn(move || {
4040            loop {
4041                let excerpt = cursor.excerpt()?;
4042
4043                // If we have already retrieved metadata for this excerpt, continue to use it.
4044                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4045                    .as_mut()
4046                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4047                {
4048                    Some(metadata)
4049                }
4050                // Otherwise, compute the intersection of the input range with the excerpt's range,
4051                // and retrieve the metadata for the resulting range.
4052                else {
4053                    let region = cursor.region()?;
4054                    let mut buffer_start;
4055                    if region.is_main_buffer {
4056                        buffer_start = region.buffer_range.start;
4057                        if query_range.start > region.range.start {
4058                            let overshoot = query_range.start - region.range.start;
4059                            buffer_start.add_assign(&overshoot);
4060                        }
4061                        buffer_start = buffer_start.min(region.buffer_range.end);
4062                    } else {
4063                        buffer_start = cursor.main_buffer_position()?;
4064                    };
4065                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4066                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4067                        && excerpt.id == end_excerpt_id
4068                    {
4069                        buffer_end = buffer_end.min(end_buffer_offset);
4070                    }
4071
4072                    if let Some(iterator) =
4073                        get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
4074                    {
4075                        Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
4076                    } else {
4077                        None
4078                    }
4079                };
4080
4081                // Visit each metadata item.
4082                if let Some((metadata_buffer_range, metadata)) =
4083                    metadata_iter.and_then(Iterator::next)
4084                {
4085                    // Find the multibuffer regions that contain the start and end of
4086                    // the metadata item's range.
4087                    if metadata_buffer_range.start > D::default() {
4088                        while let Some(region) = cursor.region() {
4089                            if region.is_main_buffer
4090                                && (region.buffer_range.end >= metadata_buffer_range.start
4091                                    || cursor.is_at_end_of_excerpt())
4092                            {
4093                                break;
4094                            }
4095                            cursor.next();
4096                        }
4097                    }
4098                    let start_region = cursor.region()?;
4099                    while let Some(region) = cursor.region() {
4100                        if region.is_main_buffer
4101                            && (region.buffer_range.end > metadata_buffer_range.end
4102                                || cursor.is_at_end_of_excerpt())
4103                        {
4104                            break;
4105                        }
4106                        cursor.next();
4107                    }
4108                    let end_region = cursor.region();
4109
4110                    // Convert the metadata item's range into multibuffer coordinates.
4111                    let mut start_position = start_region.range.start;
4112                    let region_buffer_start = start_region.buffer_range.start;
4113                    if start_region.is_main_buffer
4114                        && metadata_buffer_range.start > region_buffer_start
4115                    {
4116                        start_position
4117                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4118                        start_position = start_position.min(start_region.range.end);
4119                    }
4120
4121                    let mut end_position = max_position;
4122                    if let Some(end_region) = &end_region {
4123                        end_position = end_region.range.start;
4124                        debug_assert!(end_region.is_main_buffer);
4125                        let region_buffer_start = end_region.buffer_range.start;
4126                        if metadata_buffer_range.end > region_buffer_start {
4127                            end_position
4128                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4129                        }
4130                        end_position = end_position.min(end_region.range.end);
4131                    }
4132
4133                    if start_position <= query_range.end && end_position >= query_range.start {
4134                        return Some((start_position..end_position, metadata, excerpt));
4135                    }
4136                }
4137                // When there are no more metadata items for this excerpt, move to the next excerpt.
4138                else {
4139                    current_excerpt_metadata.take();
4140                    if let Some((end_excerpt_id, _)) = range_end
4141                        && excerpt.id == end_excerpt_id
4142                    {
4143                        return None;
4144                    }
4145                    cursor.next_excerpt();
4146                }
4147            }
4148        })
4149    }
4150
4151    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4152        let offset = position.to_offset(self);
4153
4154        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4155        cursor.seek(&DimensionPair {
4156            key: offset,
4157            value: None,
4158        });
4159        cursor.seek_to_start_of_current_excerpt();
4160        let excerpt = cursor.excerpt()?;
4161
4162        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4163        let current_position = self
4164            .anchor_before(offset)
4165            .text_anchor
4166            .to_offset(&excerpt.buffer);
4167        let excerpt_end = excerpt
4168            .buffer
4169            .anchor_before(excerpt_end.min(current_position));
4170
4171        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4172            for hunk in diff.hunks_intersecting_range_rev(
4173                excerpt.range.context.start..excerpt_end,
4174                &excerpt.buffer,
4175            ) {
4176                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4177                if hunk_end >= current_position {
4178                    continue;
4179                }
4180                let start =
4181                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4182                        .to_point(self);
4183                return Some(MultiBufferRow(start.row));
4184            }
4185        }
4186
4187        loop {
4188            cursor.prev_excerpt();
4189            let excerpt = cursor.excerpt()?;
4190
4191            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4192                continue;
4193            };
4194            let mut hunks =
4195                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4196            let Some(hunk) = hunks.next() else {
4197                continue;
4198            };
4199            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4200                .to_point(self);
4201            return Some(MultiBufferRow(start.row));
4202        }
4203    }
4204
4205    pub fn has_diff_hunks(&self) -> bool {
4206        self.diffs.values().any(|diff| !diff.is_empty())
4207    }
4208
4209    pub fn is_inside_word<T: ToOffset>(&self, position: T, for_completion: bool) -> bool {
4210        let position = position.to_offset(self);
4211        let classifier = self
4212            .char_classifier_at(position)
4213            .for_completion(for_completion);
4214        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4215        let prev_char_kind = self
4216            .reversed_chars_at(position)
4217            .next()
4218            .map(|c| classifier.kind(c));
4219        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4220    }
4221
4222    pub fn surrounding_word<T: ToOffset>(
4223        &self,
4224        start: T,
4225        for_completion: bool,
4226    ) -> (Range<usize>, Option<CharKind>) {
4227        let mut start = start.to_offset(self);
4228        let mut end = start;
4229        let mut next_chars = self.chars_at(start).peekable();
4230        let mut prev_chars = self.reversed_chars_at(start).peekable();
4231
4232        let classifier = self
4233            .char_classifier_at(start)
4234            .for_completion(for_completion);
4235
4236        let word_kind = cmp::max(
4237            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4238            next_chars.peek().copied().map(|c| classifier.kind(c)),
4239        );
4240
4241        for ch in prev_chars {
4242            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4243                start -= ch.len_utf8();
4244            } else {
4245                break;
4246            }
4247        }
4248
4249        for ch in next_chars {
4250            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4251                end += ch.len_utf8();
4252            } else {
4253                break;
4254            }
4255        }
4256
4257        (start..end, word_kind)
4258    }
4259
4260    pub fn char_kind_before<T: ToOffset>(
4261        &self,
4262        start: T,
4263        for_completion: bool,
4264    ) -> Option<CharKind> {
4265        let start = start.to_offset(self);
4266        let classifier = self
4267            .char_classifier_at(start)
4268            .for_completion(for_completion);
4269        self.reversed_chars_at(start)
4270            .next()
4271            .map(|ch| classifier.kind(ch))
4272    }
4273
4274    pub fn is_singleton(&self) -> bool {
4275        self.singleton
4276    }
4277
4278    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4279        if self.singleton {
4280            self.excerpts
4281                .iter()
4282                .next()
4283                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4284        } else {
4285            None
4286        }
4287    }
4288
4289    pub fn len(&self) -> usize {
4290        self.diff_transforms.summary().output.len
4291    }
4292
4293    pub fn is_empty(&self) -> bool {
4294        self.excerpts.summary().text.len == 0
4295    }
4296
4297    pub fn widest_line_number(&self) -> u32 {
4298        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4299        self.excerpts.summary().widest_line_number + 1
4300    }
4301
4302    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4303        let range = range.start.to_offset(self)..range.end.to_offset(self);
4304        let mut excerpts = self.cursor::<usize>();
4305        excerpts.seek(&range.start);
4306
4307        let mut chunk;
4308        let mut has_trailing_newline;
4309        let excerpt_bytes;
4310        if let Some(region) = excerpts.region() {
4311            let mut bytes = region.buffer.bytes_in_range(
4312                region.buffer_range.start + range.start - region.range.start
4313                    ..(region.buffer_range.start + range.end - region.range.start)
4314                        .min(region.buffer_range.end),
4315            );
4316            chunk = bytes.next().unwrap_or(&[][..]);
4317            excerpt_bytes = Some(bytes);
4318            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4319            if chunk.is_empty() && has_trailing_newline {
4320                chunk = b"\n";
4321                has_trailing_newline = false;
4322            }
4323        } else {
4324            chunk = &[][..];
4325            excerpt_bytes = None;
4326            has_trailing_newline = false;
4327        };
4328
4329        MultiBufferBytes {
4330            range,
4331            cursor: excerpts,
4332            excerpt_bytes,
4333            has_trailing_newline,
4334            chunk,
4335        }
4336    }
4337
4338    pub fn reversed_bytes_in_range<T: ToOffset>(
4339        &self,
4340        range: Range<T>,
4341    ) -> ReversedMultiBufferBytes<'_> {
4342        let range = range.start.to_offset(self)..range.end.to_offset(self);
4343        let mut chunks = self.reversed_chunks_in_range(range.clone());
4344        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4345        ReversedMultiBufferBytes {
4346            range,
4347            chunks,
4348            chunk,
4349        }
4350    }
4351
4352    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4353        let mut cursor = self.cursor::<Point>();
4354        cursor.seek(&Point::new(start_row.0, 0));
4355        let mut result = MultiBufferRows {
4356            point: Point::new(0, 0),
4357            is_empty: self.excerpts.is_empty(),
4358            is_singleton: self.is_singleton(),
4359            cursor,
4360        };
4361        result.seek(start_row);
4362        result
4363    }
4364
4365    pub fn chunks<T: ToOffset>(
4366        &self,
4367        range: Range<T>,
4368        language_aware: bool,
4369    ) -> MultiBufferChunks<'_> {
4370        let mut chunks = MultiBufferChunks {
4371            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4372            range: 0..0,
4373            excerpts: self.excerpts.cursor(&()),
4374            diff_transforms: self.diff_transforms.cursor(&()),
4375            diffs: &self.diffs,
4376            diff_base_chunks: None,
4377            excerpt_chunks: None,
4378            buffer_chunk: None,
4379            language_aware,
4380        };
4381        let range = range.start.to_offset(self)..range.end.to_offset(self);
4382        chunks.seek(range);
4383        chunks
4384    }
4385
4386    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4387        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4388    }
4389
4390    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4391        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4392    }
4393
4394    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4395        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4396    }
4397
4398    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4399        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4400            buffer.clip_point_utf16(Unclipped(point), bias)
4401        })
4402    }
4403
4404    pub fn offset_to_point(&self, offset: usize) -> Point {
4405        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4406    }
4407
4408    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4409        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4410    }
4411
4412    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4413        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4414    }
4415
4416    pub fn point_to_offset(&self, point: Point) -> usize {
4417        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4418    }
4419
4420    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4421        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4422    }
4423
4424    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4425        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4426    }
4427
4428    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4429        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4430    }
4431
4432    fn clip_dimension<D>(
4433        &self,
4434        position: D,
4435        bias: Bias,
4436        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4437    ) -> D
4438    where
4439        D: TextDimension + Ord + Sub<D, Output = D>,
4440    {
4441        let mut cursor = self.cursor();
4442        cursor.seek(&position);
4443        if let Some(region) = cursor.region() {
4444            if position >= region.range.end {
4445                return region.range.end;
4446            }
4447            let overshoot = position - region.range.start;
4448            let mut buffer_position = region.buffer_range.start;
4449            buffer_position.add_assign(&overshoot);
4450            let clipped_buffer_position =
4451                clip_buffer_position(region.buffer, buffer_position, bias);
4452            let mut position = region.range.start;
4453            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4454            position
4455        } else {
4456            D::from_text_summary(&self.text_summary())
4457        }
4458    }
4459
4460    fn convert_dimension<D1, D2>(
4461        &self,
4462        key: D1,
4463        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4464    ) -> D2
4465    where
4466        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4467        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4468    {
4469        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4470        cursor.seek(&DimensionPair { key, value: None });
4471        if let Some(region) = cursor.region() {
4472            if key >= region.range.end.key {
4473                return region.range.end.value.unwrap();
4474            }
4475            let start_key = region.range.start.key;
4476            let start_value = region.range.start.value.unwrap();
4477            let buffer_start_key = region.buffer_range.start.key;
4478            let buffer_start_value = region.buffer_range.start.value.unwrap();
4479            let mut buffer_key = buffer_start_key;
4480            buffer_key.add_assign(&(key - start_key));
4481            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4482            let mut result = start_value;
4483            result.add_assign(&(buffer_value - buffer_start_value));
4484            result
4485        } else {
4486            D2::from_text_summary(&self.text_summary())
4487        }
4488    }
4489
4490    pub fn point_to_buffer_offset<T: ToOffset>(
4491        &self,
4492        point: T,
4493    ) -> Option<(&BufferSnapshot, usize)> {
4494        let offset = point.to_offset(self);
4495        let mut cursor = self.cursor::<usize>();
4496        cursor.seek(&offset);
4497        let region = cursor.region()?;
4498        let overshoot = offset - region.range.start;
4499        let buffer_offset = region.buffer_range.start + overshoot;
4500        if buffer_offset == region.buffer.len() + 1
4501            && region.has_trailing_newline
4502            && !region.is_main_buffer
4503        {
4504            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4505        } else if buffer_offset > region.buffer.len() {
4506            return None;
4507        }
4508        Some((region.buffer, buffer_offset))
4509    }
4510
4511    pub fn point_to_buffer_point(
4512        &self,
4513        point: Point,
4514    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4515        let mut cursor = self.cursor::<Point>();
4516        cursor.seek(&point);
4517        let region = cursor.region()?;
4518        let overshoot = point - region.range.start;
4519        let buffer_point = region.buffer_range.start + overshoot;
4520        let excerpt = cursor.excerpt()?;
4521        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4522            && region.has_trailing_newline
4523            && !region.is_main_buffer
4524        {
4525            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4526        } else if buffer_point > region.buffer.max_point() {
4527            return None;
4528        }
4529        Some((region.buffer, buffer_point, excerpt.id))
4530    }
4531
4532    pub fn suggested_indents(
4533        &self,
4534        rows: impl IntoIterator<Item = u32>,
4535        cx: &App,
4536    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4537        let mut result = BTreeMap::new();
4538
4539        let mut rows_for_excerpt = Vec::new();
4540        let mut cursor = self.cursor::<Point>();
4541        let mut rows = rows.into_iter().peekable();
4542        let mut prev_row = u32::MAX;
4543        let mut prev_language_indent_size = IndentSize::default();
4544
4545        while let Some(row) = rows.next() {
4546            cursor.seek(&Point::new(row, 0));
4547            let Some(region) = cursor.region() else {
4548                continue;
4549            };
4550
4551            // Retrieve the language and indent size once for each disjoint region being indented.
4552            let single_indent_size = if row.saturating_sub(1) == prev_row {
4553                prev_language_indent_size
4554            } else {
4555                region
4556                    .buffer
4557                    .language_indent_size_at(Point::new(row, 0), cx)
4558            };
4559            prev_language_indent_size = single_indent_size;
4560            prev_row = row;
4561
4562            let start_buffer_row = region.buffer_range.start.row;
4563            let start_multibuffer_row = region.range.start.row;
4564            let end_multibuffer_row = region.range.end.row;
4565
4566            rows_for_excerpt.push(row);
4567            while let Some(next_row) = rows.peek().copied() {
4568                if end_multibuffer_row > next_row {
4569                    rows_for_excerpt.push(next_row);
4570                    rows.next();
4571                } else {
4572                    break;
4573                }
4574            }
4575
4576            let buffer_rows = rows_for_excerpt
4577                .drain(..)
4578                .map(|row| start_buffer_row + row - start_multibuffer_row);
4579            let buffer_indents = region
4580                .buffer
4581                .suggested_indents(buffer_rows, single_indent_size);
4582            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4583                (
4584                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4585                    indent,
4586                )
4587            });
4588            result.extend(multibuffer_indents);
4589        }
4590
4591        result
4592    }
4593
4594    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4595        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4596            let mut size = buffer.indent_size_for_line(range.start.row);
4597            size.len = size
4598                .len
4599                .min(range.end.column)
4600                .saturating_sub(range.start.column);
4601            size
4602        } else {
4603            IndentSize::spaces(0)
4604        }
4605    }
4606
4607    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4608        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4609            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4610        } else {
4611            LineIndent::spaces(0)
4612        }
4613    }
4614
4615    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4616        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4617
4618        if self.language_settings(cx).extend_comment_on_newline
4619            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4620        {
4621            let delimiters = language_scope.line_comment_prefixes();
4622            for delimiter in delimiters {
4623                if *self
4624                    .chars_at(Point::new(row.0, indent.len() as u32))
4625                    .take(delimiter.chars().count())
4626                    .collect::<String>()
4627                    .as_str()
4628                    == **delimiter
4629                {
4630                    indent.push_str(delimiter);
4631                    break;
4632                }
4633            }
4634        }
4635
4636        indent
4637    }
4638
4639    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4640    where
4641        T: ToOffset,
4642    {
4643        for char in self.reversed_chars_at(position) {
4644            if !char.is_whitespace() {
4645                return false;
4646            }
4647            if char == '\n' {
4648                return true;
4649            }
4650        }
4651        true
4652    }
4653
4654    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4655        while row.0 > 0 {
4656            row.0 -= 1;
4657            if !self.is_line_blank(row) {
4658                return Some(row);
4659            }
4660        }
4661        None
4662    }
4663
4664    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4665        if let Some((_, range)) = self.buffer_line_for_row(row) {
4666            range.end.column - range.start.column
4667        } else {
4668            0
4669        }
4670    }
4671
4672    pub fn buffer_line_for_row(
4673        &self,
4674        row: MultiBufferRow,
4675    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4676        let mut cursor = self.cursor::<Point>();
4677        let point = Point::new(row.0, 0);
4678        cursor.seek(&point);
4679        let region = cursor.region()?;
4680        let overshoot = point.min(region.range.end) - region.range.start;
4681        let buffer_point = region.buffer_range.start + overshoot;
4682        if buffer_point.row > region.buffer_range.end.row {
4683            return None;
4684        }
4685        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4686        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4687            .min(region.buffer_range.end);
4688        Some((region.buffer, line_start..line_end))
4689    }
4690
4691    pub fn max_point(&self) -> Point {
4692        self.text_summary().lines
4693    }
4694
4695    pub fn max_row(&self) -> MultiBufferRow {
4696        MultiBufferRow(self.text_summary().lines.row)
4697    }
4698
4699    pub fn text_summary(&self) -> TextSummary {
4700        self.diff_transforms.summary().output
4701    }
4702
4703    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4704    where
4705        D: TextDimension,
4706        O: ToOffset,
4707    {
4708        let range = range.start.to_offset(self)..range.end.to_offset(self);
4709        let mut cursor = self
4710            .diff_transforms
4711            .cursor::<Dimensions<usize, ExcerptOffset>>(&());
4712        cursor.seek(&range.start, Bias::Right);
4713
4714        let Some(first_transform) = cursor.item() else {
4715            return D::from_text_summary(&TextSummary::default());
4716        };
4717
4718        let diff_transform_start = cursor.start().0;
4719        let diff_transform_end = cursor.end().0;
4720        let diff_start = range.start;
4721        let start_overshoot = diff_start - diff_transform_start;
4722        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4723
4724        let mut result = match first_transform {
4725            DiffTransform::BufferContent { .. } => {
4726                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4727                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4728                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4729            }
4730            DiffTransform::DeletedHunk {
4731                buffer_id,
4732                base_text_byte_range,
4733                has_trailing_newline,
4734                ..
4735            } => {
4736                let buffer_start = base_text_byte_range.start + start_overshoot;
4737                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4738                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4739                    panic!("{:?} is in non-existent deleted hunk", range.start)
4740                };
4741
4742                let include_trailing_newline =
4743                    *has_trailing_newline && range.end >= diff_transform_end;
4744                if include_trailing_newline {
4745                    buffer_end -= 1;
4746                }
4747
4748                let mut summary =
4749                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4750
4751                if include_trailing_newline {
4752                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4753                }
4754
4755                summary
4756            }
4757        };
4758        if range.end < diff_transform_end {
4759            return result;
4760        }
4761
4762        cursor.next();
4763        result.add_assign(&D::from_text_summary(
4764            &cursor.summary(&range.end, Bias::Right),
4765        ));
4766
4767        let Some(last_transform) = cursor.item() else {
4768            return result;
4769        };
4770
4771        let overshoot = range.end - cursor.start().0;
4772        let suffix = match last_transform {
4773            DiffTransform::BufferContent { .. } => {
4774                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4775                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4776            }
4777            DiffTransform::DeletedHunk {
4778                base_text_byte_range,
4779                buffer_id,
4780                has_trailing_newline,
4781                ..
4782            } => {
4783                let buffer_end = base_text_byte_range.start + overshoot;
4784                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4785                    panic!("{:?} is in non-existent deleted hunk", range.end)
4786                };
4787
4788                let mut suffix = base_text
4789                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4790                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4791                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4792                }
4793                suffix
4794            }
4795        };
4796
4797        result.add_assign(&suffix);
4798        result
4799    }
4800
4801    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4802    where
4803        D: TextDimension,
4804    {
4805        // let mut range = range.start..range.end;
4806        let mut summary = D::zero(&());
4807        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4808        cursor.seek(&range.start, Bias::Right);
4809        if let Some(excerpt) = cursor.item() {
4810            let mut end_before_newline = cursor.end();
4811            if excerpt.has_trailing_newline {
4812                end_before_newline -= ExcerptOffset::new(1);
4813            }
4814
4815            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4816            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4817            let end_in_excerpt =
4818                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4819            summary.add_assign(
4820                &excerpt
4821                    .buffer
4822                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4823            );
4824
4825            if range.end > end_before_newline {
4826                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4827            }
4828
4829            cursor.next();
4830        }
4831
4832        if range.end > *cursor.start() {
4833            summary.add_assign(
4834                &cursor
4835                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4836                    .0,
4837            );
4838            if let Some(excerpt) = cursor.item() {
4839                range.end = cmp::max(*cursor.start(), range.end);
4840
4841                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4842                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4843                summary.add_assign(
4844                    &excerpt
4845                        .buffer
4846                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4847                );
4848            }
4849        }
4850
4851        summary
4852    }
4853
4854    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4855    where
4856        D: TextDimension + Ord + Sub<D, Output = D>,
4857    {
4858        self.summaries_for_anchors([anchor])[0]
4859    }
4860
4861    fn resolve_summary_for_anchor<D>(
4862        &self,
4863        anchor: &Anchor,
4864        excerpt_position: D,
4865        diff_transforms: &mut Cursor<
4866            DiffTransform,
4867            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4868        >,
4869    ) -> D
4870    where
4871        D: TextDimension + Ord + Sub<D, Output = D>,
4872    {
4873        loop {
4874            let transform_end_position = diff_transforms.end().0.0;
4875            let at_transform_end =
4876                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4877            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4878                diff_transforms.next();
4879                continue;
4880            }
4881
4882            let mut position = diff_transforms.start().1.0;
4883            match diff_transforms.item() {
4884                Some(DiffTransform::DeletedHunk {
4885                    buffer_id,
4886                    base_text_byte_range,
4887                    ..
4888                }) => {
4889                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4890                        && let Some(base_text) =
4891                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4892                        && base_text.can_resolve(diff_base_anchor)
4893                    {
4894                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4895                        if base_text_offset >= base_text_byte_range.start
4896                            && base_text_offset <= base_text_byte_range.end
4897                        {
4898                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4899                                base_text_byte_range.start..base_text_offset,
4900                            );
4901                            position.add_assign(&position_in_hunk);
4902                        } else if at_transform_end {
4903                            diff_transforms.next();
4904                            continue;
4905                        }
4906                    }
4907                }
4908                _ => {
4909                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4910                        diff_transforms.next();
4911                        continue;
4912                    }
4913                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4914                    position.add_assign(&overshoot);
4915                }
4916            }
4917
4918            return position;
4919        }
4920    }
4921
4922    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4923        let mut cursor = self
4924            .excerpts
4925            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
4926        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4927
4928        cursor.seek(&Some(locator), Bias::Left);
4929        if cursor.item().is_none() {
4930            cursor.next();
4931        }
4932
4933        let mut position = cursor.start().1;
4934        if let Some(excerpt) = cursor.item()
4935            && excerpt.id == anchor.excerpt_id
4936        {
4937            let excerpt_buffer_start = excerpt
4938                .buffer
4939                .offset_for_anchor(&excerpt.range.context.start);
4940            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4941            let buffer_position = cmp::min(
4942                excerpt_buffer_end,
4943                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4944            );
4945            if buffer_position > excerpt_buffer_start {
4946                position.value += buffer_position - excerpt_buffer_start;
4947            }
4948        }
4949        position
4950    }
4951
4952    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4953        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4954            excerpt_id = *replacement;
4955        }
4956        excerpt_id
4957    }
4958
4959    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4960    where
4961        D: TextDimension + Ord + Sub<D, Output = D>,
4962        I: 'a + IntoIterator<Item = &'a Anchor>,
4963    {
4964        let mut anchors = anchors.into_iter().peekable();
4965        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4966        let mut diff_transforms_cursor = self
4967            .diff_transforms
4968            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(&());
4969        diff_transforms_cursor.next();
4970
4971        let mut summaries = Vec::new();
4972        while let Some(anchor) = anchors.peek() {
4973            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4974            let excerpt_anchors = iter::from_fn(|| {
4975                let anchor = anchors.peek()?;
4976                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4977                    Some(anchors.next().unwrap())
4978                } else {
4979                    None
4980                }
4981            });
4982
4983            let locator = self.excerpt_locator_for_id(excerpt_id);
4984            cursor.seek_forward(locator, Bias::Left);
4985            if cursor.item().is_none() {
4986                cursor.next();
4987            }
4988
4989            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4990            if let Some(excerpt) = cursor.item() {
4991                if excerpt.id != excerpt_id {
4992                    let position = self.resolve_summary_for_anchor(
4993                        &Anchor::min(),
4994                        excerpt_start_position,
4995                        &mut diff_transforms_cursor,
4996                    );
4997                    summaries.extend(excerpt_anchors.map(|_| position));
4998                    continue;
4999                }
5000                let excerpt_buffer_start =
5001                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
5002                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
5003                for (buffer_summary, anchor) in excerpt
5004                    .buffer
5005                    .summaries_for_anchors_with_payload::<D, _, _>(
5006                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5007                    )
5008                {
5009                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5010                    let mut position = excerpt_start_position;
5011                    if summary > excerpt_buffer_start {
5012                        position.add_assign(&(summary - excerpt_buffer_start));
5013                    }
5014
5015                    if position > diff_transforms_cursor.start().0.0 {
5016                        diff_transforms_cursor
5017                            .seek_forward(&ExcerptDimension(position), Bias::Left);
5018                    }
5019
5020                    summaries.push(self.resolve_summary_for_anchor(
5021                        anchor,
5022                        position,
5023                        &mut diff_transforms_cursor,
5024                    ));
5025                }
5026            } else {
5027                diff_transforms_cursor
5028                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
5029                let position = self.resolve_summary_for_anchor(
5030                    &Anchor::max(),
5031                    excerpt_start_position,
5032                    &mut diff_transforms_cursor,
5033                );
5034                summaries.extend(excerpt_anchors.map(|_| position));
5035            }
5036        }
5037
5038        summaries
5039    }
5040
5041    pub fn dimensions_from_points<'a, D>(
5042        &'a self,
5043        points: impl 'a + IntoIterator<Item = Point>,
5044    ) -> impl 'a + Iterator<Item = D>
5045    where
5046        D: TextDimension + Sub<D, Output = D>,
5047    {
5048        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
5049        cursor.seek(&DimensionPair {
5050            key: Point::default(),
5051            value: None,
5052        });
5053        let mut points = points.into_iter();
5054        iter::from_fn(move || {
5055            let point = points.next()?;
5056
5057            cursor.seek_forward(&DimensionPair {
5058                key: point,
5059                value: None,
5060            });
5061
5062            if let Some(region) = cursor.region() {
5063                let overshoot = point - region.range.start.key;
5064                let buffer_point = region.buffer_range.start.key + overshoot;
5065                let mut position = region.range.start.value.unwrap();
5066                position.add_assign(
5067                    &region
5068                        .buffer
5069                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
5070                );
5071                if point == region.range.end.key && region.has_trailing_newline {
5072                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
5073                }
5074                Some(position)
5075            } else {
5076                Some(D::from_text_summary(&self.text_summary()))
5077            }
5078        })
5079    }
5080
5081    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5082    where
5083        I: 'a + IntoIterator<Item = &'a Anchor>,
5084    {
5085        let mut anchors = anchors.into_iter().enumerate().peekable();
5086        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5087        cursor.next();
5088
5089        let mut result = Vec::new();
5090
5091        while let Some((_, anchor)) = anchors.peek() {
5092            let old_excerpt_id = anchor.excerpt_id;
5093
5094            // Find the location where this anchor's excerpt should be.
5095            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5096            cursor.seek_forward(&Some(old_locator), Bias::Left);
5097
5098            if cursor.item().is_none() {
5099                cursor.next();
5100            }
5101
5102            let next_excerpt = cursor.item();
5103            let prev_excerpt = cursor.prev_item();
5104
5105            // Process all of the anchors for this excerpt.
5106            while let Some((_, anchor)) = anchors.peek() {
5107                if anchor.excerpt_id != old_excerpt_id {
5108                    break;
5109                }
5110                let (anchor_ix, anchor) = anchors.next().unwrap();
5111                let mut anchor = *anchor;
5112
5113                // Leave min and max anchors unchanged if invalid or
5114                // if the old excerpt still exists at this location
5115                let mut kept_position = next_excerpt
5116                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5117                    || old_excerpt_id == ExcerptId::max()
5118                    || old_excerpt_id == ExcerptId::min();
5119
5120                // If the old excerpt no longer exists at this location, then attempt to
5121                // find an equivalent position for this anchor in an adjacent excerpt.
5122                if !kept_position {
5123                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5124                        if excerpt.contains(&anchor) {
5125                            anchor.excerpt_id = excerpt.id;
5126                            kept_position = true;
5127                            break;
5128                        }
5129                    }
5130                }
5131
5132                // If there's no adjacent excerpt that contains the anchor's position,
5133                // then report that the anchor has lost its position.
5134                if !kept_position {
5135                    anchor = if let Some(excerpt) = next_excerpt {
5136                        let mut text_anchor = excerpt
5137                            .range
5138                            .context
5139                            .start
5140                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5141                        if text_anchor
5142                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5143                            .is_gt()
5144                        {
5145                            text_anchor = excerpt.range.context.end;
5146                        }
5147                        Anchor {
5148                            buffer_id: Some(excerpt.buffer_id),
5149                            excerpt_id: excerpt.id,
5150                            text_anchor,
5151                            diff_base_anchor: None,
5152                        }
5153                    } else if let Some(excerpt) = prev_excerpt {
5154                        let mut text_anchor = excerpt
5155                            .range
5156                            .context
5157                            .end
5158                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5159                        if text_anchor
5160                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5161                            .is_lt()
5162                        {
5163                            text_anchor = excerpt.range.context.start;
5164                        }
5165                        Anchor {
5166                            buffer_id: Some(excerpt.buffer_id),
5167                            excerpt_id: excerpt.id,
5168                            text_anchor,
5169                            diff_base_anchor: None,
5170                        }
5171                    } else if anchor.text_anchor.bias == Bias::Left {
5172                        Anchor::min()
5173                    } else {
5174                        Anchor::max()
5175                    };
5176                }
5177
5178                result.push((anchor_ix, anchor, kept_position));
5179            }
5180        }
5181        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5182        result
5183    }
5184
5185    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5186        self.anchor_at(position, Bias::Left)
5187    }
5188
5189    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5190        self.anchor_at(position, Bias::Right)
5191    }
5192
5193    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5194        let offset = position.to_offset(self);
5195
5196        // Find the given position in the diff transforms. Determine the corresponding
5197        // offset in the excerpts, and whether the position is within a deleted hunk.
5198        let mut diff_transforms = self
5199            .diff_transforms
5200            .cursor::<Dimensions<usize, ExcerptOffset>>(&());
5201        diff_transforms.seek(&offset, Bias::Right);
5202
5203        if offset == diff_transforms.start().0
5204            && bias == Bias::Left
5205            && let Some(prev_item) = diff_transforms.prev_item()
5206            && let DiffTransform::DeletedHunk { .. } = prev_item
5207        {
5208            diff_transforms.prev();
5209        }
5210        let offset_in_transform = offset - diff_transforms.start().0;
5211        let mut excerpt_offset = diff_transforms.start().1;
5212        let mut diff_base_anchor = None;
5213        if let Some(DiffTransform::DeletedHunk {
5214            buffer_id,
5215            base_text_byte_range,
5216            has_trailing_newline,
5217            ..
5218        }) = diff_transforms.item()
5219        {
5220            let diff = self.diffs.get(buffer_id).expect("missing diff");
5221            if offset_in_transform > base_text_byte_range.len() {
5222                debug_assert!(*has_trailing_newline);
5223                bias = Bias::Right;
5224            } else {
5225                diff_base_anchor = Some(
5226                    diff.base_text()
5227                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5228                );
5229                bias = Bias::Left;
5230            }
5231        } else {
5232            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5233        };
5234
5235        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5236            return Anchor {
5237                buffer_id: Some(buffer_id),
5238                excerpt_id: *excerpt_id,
5239                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5240                diff_base_anchor,
5241            };
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 if excerpt_offset.is_zero() && bias == Bias::Left {
5268            Anchor::min()
5269        } else {
5270            Anchor::max()
5271        }
5272    }
5273
5274    /// Returns an anchor for the given excerpt and text anchor,
5275    /// returns None if the excerpt_id is no longer valid.
5276    pub fn anchor_in_excerpt(
5277        &self,
5278        excerpt_id: ExcerptId,
5279        text_anchor: text::Anchor,
5280    ) -> Option<Anchor> {
5281        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5282        let locator = self.excerpt_locator_for_id(excerpt_id);
5283        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5284        cursor.seek(locator, Bias::Left);
5285        if let Some(excerpt) = cursor.item()
5286            && excerpt.id == excerpt_id
5287        {
5288            let text_anchor = excerpt.clip_anchor(text_anchor);
5289            drop(cursor);
5290            return Some(Anchor {
5291                buffer_id: Some(excerpt.buffer_id),
5292                excerpt_id,
5293                text_anchor,
5294                diff_base_anchor: None,
5295            });
5296        }
5297        None
5298    }
5299
5300    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5301        Some(self.excerpt(excerpt_id)?.range.context.clone())
5302    }
5303
5304    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5305        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5306            true
5307        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5308            excerpt.buffer.can_resolve(&anchor.text_anchor)
5309        } else {
5310            false
5311        }
5312    }
5313
5314    pub fn excerpts(
5315        &self,
5316    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5317        self.excerpts
5318            .iter()
5319            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5320    }
5321
5322    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
5323        let excerpts = self.excerpts.cursor(&());
5324        let diff_transforms = self.diff_transforms.cursor(&());
5325        MultiBufferCursor {
5326            excerpts,
5327            diff_transforms,
5328            diffs: &self.diffs,
5329            cached_region: None,
5330        }
5331    }
5332
5333    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5334        let start_locator = self.excerpt_locator_for_id(id);
5335        let mut excerpts = self
5336            .excerpts
5337            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(&());
5338        excerpts.seek(&Some(start_locator), Bias::Left);
5339        excerpts.prev();
5340
5341        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(&());
5342        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5343        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5344            diff_transforms.next();
5345        }
5346
5347        let excerpt = excerpts.item()?;
5348        Some(MultiBufferExcerpt {
5349            excerpt,
5350            offset: diff_transforms.start().output_dimension.0,
5351            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5352            excerpt_offset: excerpts.start().1.clone(),
5353            diff_transforms,
5354        })
5355    }
5356
5357    pub fn excerpt_boundaries_in_range<R, T>(
5358        &self,
5359        range: R,
5360    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5361    where
5362        R: RangeBounds<T>,
5363        T: ToOffset,
5364    {
5365        let start_offset;
5366        let start = match range.start_bound() {
5367            Bound::Included(start) => {
5368                start_offset = start.to_offset(self);
5369                Bound::Included(start_offset)
5370            }
5371            Bound::Excluded(_) => {
5372                panic!("not supported")
5373            }
5374            Bound::Unbounded => {
5375                start_offset = 0;
5376                Bound::Unbounded
5377            }
5378        };
5379        let end = match range.end_bound() {
5380            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5381            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5382            Bound::Unbounded => Bound::Unbounded,
5383        };
5384        let bounds = (start, end);
5385
5386        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5387        cursor.seek(&DimensionPair {
5388            key: start_offset,
5389            value: None,
5390        });
5391
5392        if cursor
5393            .region()
5394            .is_some_and(|region| bounds.contains(&region.range.start.key))
5395        {
5396            cursor.prev_excerpt();
5397        } else {
5398            cursor.seek_to_start_of_current_excerpt();
5399        }
5400        let mut prev_region = cursor.region();
5401
5402        cursor.next_excerpt();
5403
5404        iter::from_fn(move || {
5405            loop {
5406                if self.singleton {
5407                    return None;
5408                }
5409
5410                let next_region = cursor.region()?;
5411                cursor.next_excerpt();
5412                if !bounds.contains(&next_region.range.start.key) {
5413                    prev_region = Some(next_region);
5414                    continue;
5415                }
5416
5417                let next_region_start = next_region.range.start.value.unwrap();
5418                let next_region_end = if let Some(region) = cursor.region() {
5419                    region.range.start.value.unwrap()
5420                } else {
5421                    self.max_point()
5422                };
5423
5424                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5425                    id: region.excerpt.id,
5426                    buffer: region.excerpt.buffer.clone(),
5427                    buffer_id: region.excerpt.buffer_id,
5428                    range: region.excerpt.range.clone(),
5429                    end_row: MultiBufferRow(next_region_start.row),
5430                });
5431
5432                let next = ExcerptInfo {
5433                    id: next_region.excerpt.id,
5434                    buffer: next_region.excerpt.buffer.clone(),
5435                    buffer_id: next_region.excerpt.buffer_id,
5436                    range: next_region.excerpt.range.clone(),
5437                    end_row: if next_region.excerpt.has_trailing_newline {
5438                        MultiBufferRow(next_region_end.row - 1)
5439                    } else {
5440                        MultiBufferRow(next_region_end.row)
5441                    },
5442                };
5443
5444                let row = MultiBufferRow(next_region_start.row);
5445
5446                prev_region = Some(next_region);
5447
5448                return Some(ExcerptBoundary { row, prev, next });
5449            }
5450        })
5451    }
5452
5453    pub fn edit_count(&self) -> usize {
5454        self.edit_count
5455    }
5456
5457    pub fn non_text_state_update_count(&self) -> usize {
5458        self.non_text_state_update_count
5459    }
5460
5461    /// Returns the smallest enclosing bracket ranges containing the given range or
5462    /// None if no brackets contain range or the range is not contained in a single
5463    /// excerpt
5464    ///
5465    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5466    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5467        &self,
5468        range: Range<T>,
5469        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5470    ) -> Option<(Range<usize>, Range<usize>)> {
5471        let range = range.start.to_offset(self)..range.end.to_offset(self);
5472        let mut excerpt = self.excerpt_containing(range.clone())?;
5473        let buffer = excerpt.buffer();
5474        let excerpt_buffer_range = excerpt.buffer_range();
5475
5476        // Filter to ranges contained in the excerpt
5477        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5478            excerpt_buffer_range.contains(&open.start)
5479                && excerpt_buffer_range.contains(&close.end)
5480                && range_filter.is_none_or(|filter| filter(buffer, open, close))
5481        };
5482
5483        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5484            excerpt.map_range_to_buffer(range),
5485            Some(&range_filter),
5486        )?;
5487
5488        Some((
5489            excerpt.map_range_from_buffer(open),
5490            excerpt.map_range_from_buffer(close),
5491        ))
5492    }
5493
5494    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5495    /// not contained in a single excerpt
5496    pub fn enclosing_bracket_ranges<T: ToOffset>(
5497        &self,
5498        range: Range<T>,
5499    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5500        let range = range.start.to_offset(self)..range.end.to_offset(self);
5501        let mut excerpt = self.excerpt_containing(range.clone())?;
5502
5503        Some(
5504            excerpt
5505                .buffer()
5506                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5507                .filter_map(move |pair| {
5508                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5509                        Some((
5510                            excerpt.map_range_from_buffer(pair.open_range),
5511                            excerpt.map_range_from_buffer(pair.close_range),
5512                        ))
5513                    } else {
5514                        None
5515                    }
5516                }),
5517        )
5518    }
5519
5520    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5521    /// not contained in a single excerpt
5522    pub fn text_object_ranges<T: ToOffset>(
5523        &self,
5524        range: Range<T>,
5525        options: TreeSitterOptions,
5526    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5527        let range = range.start.to_offset(self)..range.end.to_offset(self);
5528        self.excerpt_containing(range.clone())
5529            .map(|mut excerpt| {
5530                excerpt
5531                    .buffer()
5532                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5533                    .filter_map(move |(range, text_object)| {
5534                        if excerpt.contains_buffer_range(range.clone()) {
5535                            Some((excerpt.map_range_from_buffer(range), text_object))
5536                        } else {
5537                            None
5538                        }
5539                    })
5540            })
5541            .into_iter()
5542            .flatten()
5543    }
5544
5545    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5546    /// not contained in a single excerpt
5547    pub fn bracket_ranges<T: ToOffset>(
5548        &self,
5549        range: Range<T>,
5550    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5551        let range = range.start.to_offset(self)..range.end.to_offset(self);
5552        let mut excerpt = self.excerpt_containing(range.clone())?;
5553
5554        Some(
5555            excerpt
5556                .buffer()
5557                .bracket_ranges(excerpt.map_range_to_buffer(range))
5558                .filter_map(move |pair| {
5559                    let buffer_range = pair.open_range.start..pair.close_range.end;
5560                    if excerpt.contains_buffer_range(buffer_range) {
5561                        Some((
5562                            excerpt.map_range_from_buffer(pair.open_range),
5563                            excerpt.map_range_from_buffer(pair.close_range),
5564                        ))
5565                    } else {
5566                        None
5567                    }
5568                }),
5569        )
5570    }
5571
5572    pub fn redacted_ranges<'a, T: ToOffset>(
5573        &'a self,
5574        range: Range<T>,
5575        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5576    ) -> impl Iterator<Item = Range<usize>> + 'a {
5577        let range = range.start.to_offset(self)..range.end.to_offset(self);
5578        self.lift_buffer_metadata(range, move |buffer, range| {
5579            if redaction_enabled(buffer.file()) {
5580                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5581            } else {
5582                None
5583            }
5584        })
5585        .map(|(range, _, _)| range)
5586    }
5587
5588    pub fn runnable_ranges(
5589        &self,
5590        range: Range<Anchor>,
5591    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5592        let range = range.start.to_offset(self)..range.end.to_offset(self);
5593        self.lift_buffer_metadata(range, move |buffer, range| {
5594            Some(
5595                buffer
5596                    .runnable_ranges(range.clone())
5597                    .filter(move |runnable| {
5598                        runnable.run_range.start >= range.start
5599                            && runnable.run_range.end < range.end
5600                    })
5601                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5602            )
5603        })
5604        .map(|(run_range, runnable, _)| language::RunnableRange {
5605            run_range,
5606            ..runnable
5607        })
5608    }
5609
5610    pub fn line_indents(
5611        &self,
5612        start_row: MultiBufferRow,
5613        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5614    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5615        let max_point = self.max_point();
5616        let mut cursor = self.cursor::<Point>();
5617        cursor.seek(&Point::new(start_row.0, 0));
5618        iter::from_fn(move || {
5619            let mut region = cursor.region()?;
5620            while !buffer_filter(&region.excerpt.buffer) {
5621                cursor.next();
5622                region = cursor.region()?;
5623            }
5624            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5625            let buffer_start_row =
5626                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5627
5628            let buffer_end_row = if region.is_main_buffer
5629                && (region.has_trailing_newline || region.range.end == max_point)
5630            {
5631                region.buffer_range.end.row
5632            } else {
5633                region.buffer_range.end.row.saturating_sub(1)
5634            };
5635
5636            let line_indents = region
5637                .buffer
5638                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5639            cursor.next();
5640            Some(line_indents.map(move |(buffer_row, indent)| {
5641                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5642                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5643            }))
5644        })
5645        .flatten()
5646    }
5647
5648    pub fn reversed_line_indents(
5649        &self,
5650        end_row: MultiBufferRow,
5651        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5652    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5653        let max_point = self.max_point();
5654        let mut cursor = self.cursor::<Point>();
5655        cursor.seek(&Point::new(end_row.0, 0));
5656        iter::from_fn(move || {
5657            let mut region = cursor.region()?;
5658            while !buffer_filter(&region.excerpt.buffer) {
5659                cursor.prev();
5660                region = cursor.region()?;
5661            }
5662
5663            let buffer_start_row = region.buffer_range.start.row;
5664            let buffer_end_row = if region.is_main_buffer
5665                && (region.has_trailing_newline || region.range.end == max_point)
5666            {
5667                region.buffer_range.end.row + 1
5668            } else {
5669                region.buffer_range.end.row
5670            };
5671
5672            let overshoot = end_row.0 - region.range.start.row;
5673            let buffer_end_row =
5674                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5675
5676            let line_indents = region
5677                .buffer
5678                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5679            cursor.prev();
5680            Some(line_indents.map(move |(buffer_row, indent)| {
5681                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5682                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5683            }))
5684        })
5685        .flatten()
5686    }
5687
5688    pub async fn enclosing_indent(
5689        &self,
5690        mut target_row: MultiBufferRow,
5691    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5692        let max_row = MultiBufferRow(self.max_point().row);
5693        if target_row >= max_row {
5694            return None;
5695        }
5696
5697        let mut target_indent = self.line_indent_for_row(target_row);
5698
5699        // If the current row is at the start of an indented block, we want to return this
5700        // block as the enclosing indent.
5701        if !target_indent.is_line_empty() && target_row < max_row {
5702            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5703            if !next_line_indent.is_line_empty()
5704                && target_indent.raw_len() < next_line_indent.raw_len()
5705            {
5706                target_indent = next_line_indent;
5707                target_row.0 += 1;
5708            }
5709        }
5710
5711        const SEARCH_ROW_LIMIT: u32 = 25000;
5712        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5713        const YIELD_INTERVAL: u32 = 100;
5714
5715        let mut accessed_row_counter = 0;
5716
5717        // If there is a blank line at the current row, search for the next non indented lines
5718        if target_indent.is_line_empty() {
5719            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5720            let end =
5721                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5722
5723            let mut non_empty_line_above = None;
5724            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5725                if row < start {
5726                    break;
5727                }
5728                accessed_row_counter += 1;
5729                if accessed_row_counter == YIELD_INTERVAL {
5730                    accessed_row_counter = 0;
5731                    yield_now().await;
5732                }
5733                if !indent.is_line_empty() {
5734                    non_empty_line_above = Some((row, indent));
5735                    break;
5736                }
5737            }
5738
5739            let mut non_empty_line_below = None;
5740            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5741                if row > end {
5742                    break;
5743                }
5744                accessed_row_counter += 1;
5745                if accessed_row_counter == YIELD_INTERVAL {
5746                    accessed_row_counter = 0;
5747                    yield_now().await;
5748                }
5749                if !indent.is_line_empty() {
5750                    non_empty_line_below = Some((row, indent));
5751                    break;
5752                }
5753            }
5754
5755            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5756                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5757                    if above_indent.raw_len() >= below_indent.raw_len() {
5758                        (above_row, above_indent)
5759                    } else {
5760                        (below_row, below_indent)
5761                    }
5762                }
5763                (Some(above), None) => above,
5764                (None, Some(below)) => below,
5765                _ => return None,
5766            };
5767
5768            target_indent = indent;
5769            target_row = row;
5770        }
5771
5772        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5773        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5774
5775        let mut start_indent = None;
5776        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5777            if row < start {
5778                break;
5779            }
5780            accessed_row_counter += 1;
5781            if accessed_row_counter == YIELD_INTERVAL {
5782                accessed_row_counter = 0;
5783                yield_now().await;
5784            }
5785            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5786                start_indent = Some((row, indent));
5787                break;
5788            }
5789        }
5790        let (start_row, start_indent_size) = start_indent?;
5791
5792        let mut end_indent = (end, None);
5793        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5794            if row > end {
5795                break;
5796            }
5797            accessed_row_counter += 1;
5798            if accessed_row_counter == YIELD_INTERVAL {
5799                accessed_row_counter = 0;
5800                yield_now().await;
5801            }
5802            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5803                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5804                break;
5805            }
5806        }
5807        let (end_row, end_indent_size) = end_indent;
5808
5809        let indent = if let Some(end_indent_size) = end_indent_size {
5810            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5811                start_indent_size
5812            } else {
5813                end_indent_size
5814            }
5815        } else {
5816            start_indent_size
5817        };
5818
5819        Some((start_row..end_row, indent))
5820    }
5821
5822    pub fn indent_guides_in_range<T: ToPoint>(
5823        &self,
5824        range: Range<T>,
5825        ignore_disabled_for_language: bool,
5826        cx: &App,
5827    ) -> impl Iterator<Item = IndentGuide> {
5828        let range = range.start.to_point(self)..range.end.to_point(self);
5829        let start_row = MultiBufferRow(range.start.row);
5830        let end_row = MultiBufferRow(range.end.row);
5831
5832        let mut row_indents = self.line_indents(start_row, |buffer| {
5833            let settings =
5834                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5835            settings.indent_guides.enabled || ignore_disabled_for_language
5836        });
5837
5838        let mut result = Vec::new();
5839        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5840
5841        let mut prev_settings = None;
5842        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5843            if first_row > end_row {
5844                break;
5845            }
5846            let current_depth = indent_stack.len() as u32;
5847
5848            // Avoid retrieving the language settings repeatedly for every buffer row.
5849            if let Some((prev_buffer_id, _)) = &prev_settings
5850                && prev_buffer_id != &buffer.remote_id()
5851            {
5852                prev_settings.take();
5853            }
5854            let settings = &prev_settings
5855                .get_or_insert_with(|| {
5856                    (
5857                        buffer.remote_id(),
5858                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5859                    )
5860                })
5861                .1;
5862            let tab_size = settings.tab_size.get();
5863
5864            // When encountering empty, continue until found useful line indent
5865            // then add to the indent stack with the depth found
5866            let mut found_indent = false;
5867            let mut last_row = first_row;
5868            if line_indent.is_line_blank() {
5869                while !found_indent {
5870                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5871                        break;
5872                    };
5873                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5874                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5875                        break;
5876                    }
5877
5878                    if new_line_indent.is_line_blank() {
5879                        continue;
5880                    }
5881                    last_row = target_row.min(end_row);
5882                    line_indent = new_line_indent;
5883                    found_indent = true;
5884                    break;
5885                }
5886            } else {
5887                found_indent = true
5888            }
5889
5890            let depth = if found_indent {
5891                line_indent.len(tab_size) / tab_size
5892            } else {
5893                0
5894            };
5895
5896            match depth.cmp(&current_depth) {
5897                cmp::Ordering::Less => {
5898                    for _ in 0..(current_depth - depth) {
5899                        let mut indent = indent_stack.pop().unwrap();
5900                        if last_row != first_row {
5901                            // In this case, we landed on an empty row, had to seek forward,
5902                            // and discovered that the indent we where on is ending.
5903                            // This means that the last display row must
5904                            // be on line that ends this indent range, so we
5905                            // should display the range up to the first non-empty line
5906                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5907                        }
5908
5909                        result.push(indent)
5910                    }
5911                }
5912                cmp::Ordering::Greater => {
5913                    for next_depth in current_depth..depth {
5914                        indent_stack.push(IndentGuide {
5915                            buffer_id: buffer.remote_id(),
5916                            start_row: first_row,
5917                            end_row: last_row,
5918                            depth: next_depth,
5919                            tab_size,
5920                            settings: settings.indent_guides,
5921                        });
5922                    }
5923                }
5924                _ => {}
5925            }
5926
5927            for indent in indent_stack.iter_mut() {
5928                indent.end_row = last_row;
5929            }
5930        }
5931
5932        result.extend(indent_stack);
5933        result.into_iter()
5934    }
5935
5936    pub fn trailing_excerpt_update_count(&self) -> usize {
5937        self.trailing_excerpt_update_count
5938    }
5939
5940    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5941        self.point_to_buffer_offset(point)
5942            .and_then(|(buffer, _)| buffer.file())
5943    }
5944
5945    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5946        self.point_to_buffer_offset(point)
5947            .and_then(|(buffer, offset)| buffer.language_at(offset))
5948    }
5949
5950    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5951        self.excerpts
5952            .first()
5953            .map(|excerpt| &excerpt.buffer)
5954            .map(|buffer| {
5955                language_settings(
5956                    buffer.language().map(|language| language.name()),
5957                    buffer.file(),
5958                    cx,
5959                )
5960            })
5961            .unwrap_or_else(move || self.language_settings_at(0, cx))
5962    }
5963
5964    pub fn language_settings_at<'a, T: ToOffset>(
5965        &'a self,
5966        point: T,
5967        cx: &'a App,
5968    ) -> Cow<'a, LanguageSettings> {
5969        let mut language = None;
5970        let mut file = None;
5971        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5972            language = buffer.language_at(offset);
5973            file = buffer.file();
5974        }
5975        language_settings(language.map(|l| l.name()), file, cx)
5976    }
5977
5978    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5979        self.point_to_buffer_offset(point)
5980            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5981    }
5982
5983    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5984        self.point_to_buffer_offset(point)
5985            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5986            .unwrap_or_default()
5987    }
5988
5989    pub fn language_indent_size_at<T: ToOffset>(
5990        &self,
5991        position: T,
5992        cx: &App,
5993    ) -> Option<IndentSize> {
5994        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5995        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5996    }
5997
5998    pub fn is_dirty(&self) -> bool {
5999        self.is_dirty
6000    }
6001
6002    pub fn has_deleted_file(&self) -> bool {
6003        self.has_deleted_file
6004    }
6005
6006    pub fn has_conflict(&self) -> bool {
6007        self.has_conflict
6008    }
6009
6010    pub fn has_diagnostics(&self) -> bool {
6011        self.excerpts
6012            .iter()
6013            .any(|excerpt| excerpt.buffer.has_diagnostics())
6014    }
6015
6016    pub fn diagnostic_group(
6017        &self,
6018        buffer_id: BufferId,
6019        group_id: usize,
6020    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
6021        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
6022            if buffer.remote_id() != buffer_id {
6023                return None;
6024            };
6025            Some(
6026                buffer
6027                    .diagnostics_in_range(range, false)
6028                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6029                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
6030            )
6031        })
6032        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6033    }
6034
6035    pub fn diagnostics_in_range<'a, T>(
6036        &'a self,
6037        range: Range<T>,
6038    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
6039    where
6040        T: 'a
6041            + text::ToOffset
6042            + text::FromAnchor
6043            + TextDimension
6044            + Ord
6045            + Sub<T, Output = T>
6046            + fmt::Debug,
6047    {
6048        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6049            Some(
6050                buffer
6051                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6052                    .map(|entry| (entry.range, entry.diagnostic)),
6053            )
6054        })
6055        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6056    }
6057
6058    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
6059        &'a self,
6060        range: Range<T>,
6061    ) -> impl Iterator<Item = (BufferId, DiagnosticEntry<T>)> + 'a
6062    where
6063        T: 'a
6064            + text::ToOffset
6065            + text::FromAnchor
6066            + TextDimension
6067            + Ord
6068            + Sub<T, Output = T>
6069            + fmt::Debug,
6070    {
6071        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6072            Some(
6073                buffer
6074                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6075                    .map(|entry| (entry.range, entry.diagnostic)),
6076            )
6077        })
6078        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntry { diagnostic, range }))
6079    }
6080
6081    pub fn syntax_ancestor<T: ToOffset>(
6082        &self,
6083        range: Range<T>,
6084    ) -> Option<(tree_sitter::Node<'_>, MultiOrSingleBufferOffsetRange)> {
6085        let range = range.start.to_offset(self)..range.end.to_offset(self);
6086        let mut excerpt = self.excerpt_containing(range.clone())?;
6087        let node = excerpt
6088            .buffer()
6089            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6090        let node_range = node.byte_range();
6091        let range = if excerpt.contains_buffer_range(node_range.clone()) {
6092            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
6093        } else {
6094            MultiOrSingleBufferOffsetRange::Single(node_range)
6095        };
6096        Some((node, range))
6097    }
6098
6099    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6100        let (excerpt_id, _, buffer) = self.as_singleton()?;
6101        let outline = buffer.outline(theme)?;
6102        Some(Outline::new(
6103            outline
6104                .items
6105                .into_iter()
6106                .flat_map(|item| {
6107                    Some(OutlineItem {
6108                        depth: item.depth,
6109                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
6110                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
6111                        text: item.text,
6112                        highlight_ranges: item.highlight_ranges,
6113                        name_ranges: item.name_ranges,
6114                        body_range: item.body_range.and_then(|body_range| {
6115                            Some(
6116                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
6117                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
6118                            )
6119                        }),
6120                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6121                            Some(
6122                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6123                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6124                            )
6125                        }),
6126                    })
6127                })
6128                .collect(),
6129        ))
6130    }
6131
6132    pub fn symbols_containing<T: ToOffset>(
6133        &self,
6134        offset: T,
6135        theme: Option<&SyntaxTheme>,
6136    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6137        let anchor = self.anchor_before(offset);
6138        let excerpt_id = anchor.excerpt_id;
6139        let excerpt = self.excerpt(excerpt_id)?;
6140        Some((
6141            excerpt.buffer_id,
6142            excerpt
6143                .buffer
6144                .symbols_containing(anchor.text_anchor, theme)
6145                .into_iter()
6146                .flatten()
6147                .flat_map(|item| {
6148                    Some(OutlineItem {
6149                        depth: item.depth,
6150                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6151                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6152                        text: item.text,
6153                        highlight_ranges: item.highlight_ranges,
6154                        name_ranges: item.name_ranges,
6155                        body_range: item.body_range.and_then(|body_range| {
6156                            Some(
6157                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6158                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6159                            )
6160                        }),
6161                        annotation_range: item.annotation_range.and_then(|body_range| {
6162                            Some(
6163                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6164                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6165                            )
6166                        }),
6167                    })
6168                })
6169                .collect(),
6170        ))
6171    }
6172
6173    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6174        if id == ExcerptId::min() {
6175            Locator::min_ref()
6176        } else if id == ExcerptId::max() {
6177            Locator::max_ref()
6178        } else {
6179            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6180            cursor.seek(&id, Bias::Left);
6181            if let Some(entry) = cursor.item()
6182                && entry.id == id
6183            {
6184                return &entry.locator;
6185            }
6186            panic!("invalid excerpt id {id:?}")
6187        }
6188    }
6189
6190    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6191    fn excerpt_locators_for_ids(
6192        &self,
6193        ids: impl IntoIterator<Item = ExcerptId>,
6194    ) -> SmallVec<[Locator; 1]> {
6195        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6196        sorted_ids.sort_unstable();
6197        let mut locators = SmallVec::new();
6198
6199        while sorted_ids.last() == Some(&ExcerptId::max()) {
6200            sorted_ids.pop();
6201            if let Some(mapping) = self.excerpt_ids.last() {
6202                locators.push(mapping.locator.clone());
6203            }
6204        }
6205
6206        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6207        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6208            sorted_ids.next();
6209            if let Some(mapping) = self.excerpt_ids.first() {
6210                locators.push(mapping.locator.clone());
6211            }
6212        }
6213
6214        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6215        for id in sorted_ids {
6216            if cursor.seek_forward(&id, Bias::Left) {
6217                locators.push(cursor.item().unwrap().locator.clone());
6218            } else {
6219                panic!("invalid excerpt id {:?}", id);
6220            }
6221        }
6222
6223        locators.sort_unstable();
6224        locators
6225    }
6226
6227    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6228        Some(self.excerpt(excerpt_id)?.buffer_id)
6229    }
6230
6231    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6232        Some(&self.excerpt(excerpt_id)?.buffer)
6233    }
6234
6235    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6236        let mut cursor = self
6237            .excerpts
6238            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(&());
6239        let locator = self.excerpt_locator_for_id(excerpt_id);
6240        if cursor.seek(&Some(locator), Bias::Left) {
6241            let start = cursor.start().1.clone();
6242            let end = cursor.end().1;
6243            let mut diff_transforms = self
6244                .diff_transforms
6245                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(&());
6246            diff_transforms.seek(&start, Bias::Left);
6247            let overshoot = start.0 - diff_transforms.start().0.0;
6248            let start = diff_transforms.start().1.0 + overshoot;
6249            diff_transforms.seek(&end, Bias::Right);
6250            let overshoot = end.0 - diff_transforms.start().0.0;
6251            let end = diff_transforms.start().1.0 + overshoot;
6252            Some(start..end)
6253        } else {
6254            None
6255        }
6256    }
6257
6258    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6259        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6260        let locator = self.excerpt_locator_for_id(excerpt_id);
6261        if cursor.seek(&Some(locator), Bias::Left)
6262            && let Some(excerpt) = cursor.item()
6263        {
6264            return Some(excerpt.range.context.clone());
6265        }
6266        None
6267    }
6268
6269    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6270        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6271        let locator = self.excerpt_locator_for_id(excerpt_id);
6272        cursor.seek(&Some(locator), Bias::Left);
6273        if let Some(excerpt) = cursor.item()
6274            && excerpt.id == excerpt_id
6275        {
6276            return Some(excerpt);
6277        }
6278        None
6279    }
6280
6281    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6282    pub fn excerpt_containing<T: ToOffset>(
6283        &self,
6284        range: Range<T>,
6285    ) -> Option<MultiBufferExcerpt<'_>> {
6286        let range = range.start.to_offset(self)..range.end.to_offset(self);
6287        let mut cursor = self.cursor::<usize>();
6288        cursor.seek(&range.start);
6289
6290        let start_excerpt = cursor.excerpt()?;
6291        if range.end != range.start {
6292            cursor.seek_forward(&range.end);
6293            if cursor.excerpt()?.id != start_excerpt.id {
6294                return None;
6295            }
6296        }
6297
6298        cursor.seek_to_start_of_current_excerpt();
6299        let region = cursor.region()?;
6300        let offset = region.range.start;
6301        let buffer_offset = start_excerpt.buffer_start_offset();
6302        let excerpt_offset = cursor.excerpts.start().clone();
6303        Some(MultiBufferExcerpt {
6304            diff_transforms: cursor.diff_transforms,
6305            excerpt: start_excerpt,
6306            offset,
6307            buffer_offset,
6308            excerpt_offset,
6309        })
6310    }
6311
6312    pub fn selections_in_range<'a>(
6313        &'a self,
6314        range: &'a Range<Anchor>,
6315        include_local: bool,
6316    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6317        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6318        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6319        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6320        cursor.seek(start_locator, Bias::Left);
6321        cursor
6322            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6323            .flat_map(move |excerpt| {
6324                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6325                if excerpt.id == range.start.excerpt_id {
6326                    query_range.start = range.start.text_anchor;
6327                }
6328                if excerpt.id == range.end.excerpt_id {
6329                    query_range.end = range.end.text_anchor;
6330                }
6331
6332                excerpt
6333                    .buffer
6334                    .selections_in_range(query_range, include_local)
6335                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6336                        selections.map(move |selection| {
6337                            let mut start = Anchor {
6338                                buffer_id: Some(excerpt.buffer_id),
6339                                excerpt_id: excerpt.id,
6340                                text_anchor: selection.start,
6341                                diff_base_anchor: None,
6342                            };
6343                            let mut end = Anchor {
6344                                buffer_id: Some(excerpt.buffer_id),
6345                                excerpt_id: excerpt.id,
6346                                text_anchor: selection.end,
6347                                diff_base_anchor: None,
6348                            };
6349                            if range.start.cmp(&start, self).is_gt() {
6350                                start = range.start;
6351                            }
6352                            if range.end.cmp(&end, self).is_lt() {
6353                                end = range.end;
6354                            }
6355
6356                            (
6357                                replica_id,
6358                                line_mode,
6359                                cursor_shape,
6360                                Selection {
6361                                    id: selection.id,
6362                                    start,
6363                                    end,
6364                                    reversed: selection.reversed,
6365                                    goal: selection.goal,
6366                                },
6367                            )
6368                        })
6369                    })
6370            })
6371    }
6372
6373    pub fn show_headers(&self) -> bool {
6374        self.show_headers
6375    }
6376
6377    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6378        self.diffs.get(&buffer_id)
6379    }
6380}
6381
6382#[cfg(any(test, feature = "test-support"))]
6383impl MultiBufferSnapshot {
6384    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6385        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6386        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6387        start..end
6388    }
6389
6390    #[cfg(any(test, feature = "test-support"))]
6391    fn check_invariants(&self) {
6392        let excerpts = self.excerpts.items(&());
6393        let excerpt_ids = self.excerpt_ids.items(&());
6394
6395        for (ix, excerpt) in excerpts.iter().enumerate() {
6396            if ix == 0 {
6397                if excerpt.locator <= Locator::min() {
6398                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6399                }
6400            } else if excerpt.locator <= excerpts[ix - 1].locator {
6401                panic!("excerpts are out-of-order: {:?}", excerpts);
6402            }
6403        }
6404
6405        for (ix, entry) in excerpt_ids.iter().enumerate() {
6406            if ix == 0 {
6407                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6408                    panic!("invalid first excerpt id {:?}", entry.id);
6409                }
6410            } else if entry.id <= excerpt_ids[ix - 1].id {
6411                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6412            }
6413        }
6414
6415        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6416            panic!(
6417                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6418                self.excerpts.summary().text.len,
6419                self.diff_transforms.summary().input,
6420                self.diff_transforms.items(&()),
6421            );
6422        }
6423
6424        let mut prev_transform: Option<&DiffTransform> = None;
6425        for item in self.diff_transforms.iter() {
6426            if let DiffTransform::BufferContent {
6427                summary,
6428                inserted_hunk_info,
6429            } = item
6430            {
6431                if let Some(DiffTransform::BufferContent {
6432                    inserted_hunk_info: prev_inserted_hunk_info,
6433                    ..
6434                }) = prev_transform
6435                    && *inserted_hunk_info == *prev_inserted_hunk_info
6436                {
6437                    panic!(
6438                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6439                        self.diff_transforms.items(&())
6440                    );
6441                }
6442                if summary.len == 0 && !self.is_empty() {
6443                    panic!("empty buffer content transform");
6444                }
6445            }
6446            prev_transform = Some(item);
6447        }
6448    }
6449}
6450
6451impl<'a, D> MultiBufferCursor<'a, D>
6452where
6453    D: TextDimension + Ord + Sub<D, Output = D>,
6454{
6455    fn seek(&mut self, position: &D) {
6456        self.cached_region.take();
6457        self.diff_transforms
6458            .seek(&OutputDimension(*position), Bias::Right);
6459        if self.diff_transforms.item().is_none()
6460            && *position == self.diff_transforms.start().output_dimension.0
6461        {
6462            self.diff_transforms.prev();
6463        }
6464
6465        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6466        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6467            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6468            excerpt_position.add_assign(&overshoot);
6469        }
6470
6471        self.excerpts
6472            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
6473        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6474            self.excerpts.prev();
6475        }
6476    }
6477
6478    fn seek_forward(&mut self, position: &D) {
6479        self.cached_region.take();
6480        self.diff_transforms
6481            .seek_forward(&OutputDimension(*position), Bias::Right);
6482        if self.diff_transforms.item().is_none()
6483            && *position == self.diff_transforms.start().output_dimension.0
6484        {
6485            self.diff_transforms.prev();
6486        }
6487
6488        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6489        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6490        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6491            excerpt_position.add_assign(&overshoot);
6492        }
6493
6494        self.excerpts
6495            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
6496        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6497            self.excerpts.prev();
6498        }
6499    }
6500
6501    fn next_excerpt(&mut self) {
6502        self.excerpts.next();
6503        self.seek_to_start_of_current_excerpt();
6504    }
6505
6506    fn prev_excerpt(&mut self) {
6507        self.excerpts.prev();
6508        self.seek_to_start_of_current_excerpt();
6509    }
6510
6511    fn seek_to_start_of_current_excerpt(&mut self) {
6512        self.cached_region.take();
6513        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6514        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6515            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6516            && self.diff_transforms.next_item().is_some()
6517        {
6518            self.diff_transforms.next();
6519        }
6520    }
6521
6522    fn next(&mut self) {
6523        self.cached_region.take();
6524        match self
6525            .diff_transforms
6526            .end()
6527            .excerpt_dimension
6528            .cmp(&self.excerpts.end())
6529        {
6530            cmp::Ordering::Less => self.diff_transforms.next(),
6531            cmp::Ordering::Greater => self.excerpts.next(),
6532            cmp::Ordering::Equal => {
6533                self.diff_transforms.next();
6534                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6535                    || self.diff_transforms.item().is_none()
6536                {
6537                    self.excerpts.next();
6538                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6539                    self.diff_transforms.item()
6540                    && self
6541                        .excerpts
6542                        .item()
6543                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6544                {
6545                    self.excerpts.next();
6546                }
6547            }
6548        }
6549    }
6550
6551    fn prev(&mut self) {
6552        self.cached_region.take();
6553        match self
6554            .diff_transforms
6555            .start()
6556            .excerpt_dimension
6557            .cmp(self.excerpts.start())
6558        {
6559            cmp::Ordering::Less => self.excerpts.prev(),
6560            cmp::Ordering::Greater => self.diff_transforms.prev(),
6561            cmp::Ordering::Equal => {
6562                self.diff_transforms.prev();
6563                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6564                    || self.diff_transforms.item().is_none()
6565                {
6566                    self.excerpts.prev();
6567                }
6568            }
6569        }
6570    }
6571
6572    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6573        if self.cached_region.is_none() {
6574            self.cached_region = self.build_region();
6575        }
6576        self.cached_region.clone()
6577    }
6578
6579    fn is_at_start_of_excerpt(&mut self) -> bool {
6580        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6581            return false;
6582        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6583            return true;
6584        }
6585
6586        self.diff_transforms.prev();
6587        let prev_transform = self.diff_transforms.item();
6588        self.diff_transforms.next();
6589
6590        prev_transform.is_none_or(|next_transform| {
6591            matches!(next_transform, DiffTransform::BufferContent { .. })
6592        })
6593    }
6594
6595    fn is_at_end_of_excerpt(&mut self) -> bool {
6596        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6597            return false;
6598        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6599            || self.diff_transforms.item().is_none()
6600        {
6601            return true;
6602        }
6603
6604        let next_transform = self.diff_transforms.next_item();
6605        next_transform.is_none_or(|next_transform| match next_transform {
6606            DiffTransform::BufferContent { .. } => true,
6607            DiffTransform::DeletedHunk { hunk_info, .. } => self
6608                .excerpts
6609                .item()
6610                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6611        })
6612    }
6613
6614    fn main_buffer_position(&self) -> Option<D> {
6615        let excerpt = self.excerpts.item()?;
6616        let buffer = &excerpt.buffer;
6617        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6618        let mut buffer_start = buffer_context_start;
6619        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6620        buffer_start.add_assign(&overshoot);
6621        Some(buffer_start)
6622    }
6623
6624    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6625        let excerpt = self.excerpts.item()?;
6626        match self.diff_transforms.item()? {
6627            DiffTransform::DeletedHunk {
6628                buffer_id,
6629                base_text_byte_range,
6630                has_trailing_newline,
6631                hunk_info,
6632                ..
6633            } => {
6634                let diff = self.diffs.get(buffer_id)?;
6635                let buffer = diff.base_text();
6636                let mut rope_cursor = buffer.as_rope().cursor(0);
6637                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6638                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6639                let mut buffer_end = buffer_start;
6640                buffer_end.add_assign(&buffer_range_len);
6641                let start = self.diff_transforms.start().output_dimension.0;
6642                let end = self.diff_transforms.end().output_dimension.0;
6643                Some(MultiBufferRegion {
6644                    buffer,
6645                    excerpt,
6646                    has_trailing_newline: *has_trailing_newline,
6647                    is_main_buffer: false,
6648                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6649                        hunk_info.hunk_secondary_status,
6650                    )),
6651                    buffer_range: buffer_start..buffer_end,
6652                    range: start..end,
6653                })
6654            }
6655            DiffTransform::BufferContent {
6656                inserted_hunk_info, ..
6657            } => {
6658                let buffer = &excerpt.buffer;
6659                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6660
6661                let mut start = self.diff_transforms.start().output_dimension.0;
6662                let mut buffer_start = buffer_context_start;
6663                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6664                    let overshoot =
6665                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6666                    start.add_assign(&overshoot);
6667                } else {
6668                    let overshoot =
6669                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6670                    buffer_start.add_assign(&overshoot);
6671                }
6672
6673                let mut end;
6674                let mut buffer_end;
6675                let has_trailing_newline;
6676                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6677                    let overshoot =
6678                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6679                    end = self.diff_transforms.end().output_dimension.0;
6680                    buffer_end = buffer_context_start;
6681                    buffer_end.add_assign(&overshoot);
6682                    has_trailing_newline = false;
6683                } else {
6684                    let overshoot =
6685                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6686                    end = self.diff_transforms.start().output_dimension.0;
6687                    end.add_assign(&overshoot);
6688                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6689                    has_trailing_newline = excerpt.has_trailing_newline;
6690                };
6691
6692                Some(MultiBufferRegion {
6693                    buffer,
6694                    excerpt,
6695                    has_trailing_newline,
6696                    is_main_buffer: true,
6697                    diff_hunk_status: inserted_hunk_info
6698                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6699                    buffer_range: buffer_start..buffer_end,
6700                    range: start..end,
6701                })
6702            }
6703        }
6704    }
6705
6706    fn excerpt(&self) -> Option<&'a Excerpt> {
6707        self.excerpts.item()
6708    }
6709}
6710
6711impl History {
6712    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6713        self.transaction_depth += 1;
6714        if self.transaction_depth == 1 {
6715            let id = self.next_transaction_id.tick();
6716            self.undo_stack.push(Transaction {
6717                id,
6718                buffer_transactions: Default::default(),
6719                first_edit_at: now,
6720                last_edit_at: now,
6721                suppress_grouping: false,
6722            });
6723            Some(id)
6724        } else {
6725            None
6726        }
6727    }
6728
6729    fn end_transaction(
6730        &mut self,
6731        now: Instant,
6732        buffer_transactions: HashMap<BufferId, TransactionId>,
6733    ) -> bool {
6734        assert_ne!(self.transaction_depth, 0);
6735        self.transaction_depth -= 1;
6736        if self.transaction_depth == 0 {
6737            if buffer_transactions.is_empty() {
6738                self.undo_stack.pop();
6739                false
6740            } else {
6741                self.redo_stack.clear();
6742                let transaction = self.undo_stack.last_mut().unwrap();
6743                transaction.last_edit_at = now;
6744                for (buffer_id, transaction_id) in buffer_transactions {
6745                    transaction
6746                        .buffer_transactions
6747                        .entry(buffer_id)
6748                        .or_insert(transaction_id);
6749                }
6750                true
6751            }
6752        } else {
6753            false
6754        }
6755    }
6756
6757    fn push_transaction<'a, T>(
6758        &mut self,
6759        buffer_transactions: T,
6760        now: Instant,
6761        cx: &Context<MultiBuffer>,
6762    ) where
6763        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6764    {
6765        assert_eq!(self.transaction_depth, 0);
6766        let transaction = Transaction {
6767            id: self.next_transaction_id.tick(),
6768            buffer_transactions: buffer_transactions
6769                .into_iter()
6770                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6771                .collect(),
6772            first_edit_at: now,
6773            last_edit_at: now,
6774            suppress_grouping: false,
6775        };
6776        if !transaction.buffer_transactions.is_empty() {
6777            self.undo_stack.push(transaction);
6778            self.redo_stack.clear();
6779        }
6780    }
6781
6782    fn finalize_last_transaction(&mut self) {
6783        if let Some(transaction) = self.undo_stack.last_mut() {
6784            transaction.suppress_grouping = true;
6785        }
6786    }
6787
6788    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6789        if let Some(ix) = self
6790            .undo_stack
6791            .iter()
6792            .rposition(|transaction| transaction.id == transaction_id)
6793        {
6794            Some(self.undo_stack.remove(ix))
6795        } else if let Some(ix) = self
6796            .redo_stack
6797            .iter()
6798            .rposition(|transaction| transaction.id == transaction_id)
6799        {
6800            Some(self.redo_stack.remove(ix))
6801        } else {
6802            None
6803        }
6804    }
6805
6806    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6807        self.undo_stack
6808            .iter()
6809            .find(|transaction| transaction.id == transaction_id)
6810            .or_else(|| {
6811                self.redo_stack
6812                    .iter()
6813                    .find(|transaction| transaction.id == transaction_id)
6814            })
6815    }
6816
6817    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6818        self.undo_stack
6819            .iter_mut()
6820            .find(|transaction| transaction.id == transaction_id)
6821            .or_else(|| {
6822                self.redo_stack
6823                    .iter_mut()
6824                    .find(|transaction| transaction.id == transaction_id)
6825            })
6826    }
6827
6828    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6829        assert_eq!(self.transaction_depth, 0);
6830        if let Some(transaction) = self.undo_stack.pop() {
6831            self.redo_stack.push(transaction);
6832            self.redo_stack.last_mut()
6833        } else {
6834            None
6835        }
6836    }
6837
6838    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6839        assert_eq!(self.transaction_depth, 0);
6840        if let Some(transaction) = self.redo_stack.pop() {
6841            self.undo_stack.push(transaction);
6842            self.undo_stack.last_mut()
6843        } else {
6844            None
6845        }
6846    }
6847
6848    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6849        let ix = self
6850            .undo_stack
6851            .iter()
6852            .rposition(|transaction| transaction.id == transaction_id)?;
6853        let transaction = self.undo_stack.remove(ix);
6854        self.redo_stack.push(transaction);
6855        self.redo_stack.last()
6856    }
6857
6858    fn group(&mut self) -> Option<TransactionId> {
6859        let mut count = 0;
6860        let mut transactions = self.undo_stack.iter();
6861        if let Some(mut transaction) = transactions.next_back() {
6862            while let Some(prev_transaction) = transactions.next_back() {
6863                if !prev_transaction.suppress_grouping
6864                    && transaction.first_edit_at - prev_transaction.last_edit_at
6865                        <= self.group_interval
6866                {
6867                    transaction = prev_transaction;
6868                    count += 1;
6869                } else {
6870                    break;
6871                }
6872            }
6873        }
6874        self.group_trailing(count)
6875    }
6876
6877    fn group_until(&mut self, transaction_id: TransactionId) {
6878        let mut count = 0;
6879        for transaction in self.undo_stack.iter().rev() {
6880            if transaction.id == transaction_id {
6881                self.group_trailing(count);
6882                break;
6883            } else if transaction.suppress_grouping {
6884                break;
6885            } else {
6886                count += 1;
6887            }
6888        }
6889    }
6890
6891    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6892        let new_len = self.undo_stack.len() - n;
6893        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6894        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6895            if let Some(transaction) = transactions_to_merge.last() {
6896                last_transaction.last_edit_at = transaction.last_edit_at;
6897            }
6898            for to_merge in transactions_to_merge {
6899                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6900                    last_transaction
6901                        .buffer_transactions
6902                        .entry(*buffer_id)
6903                        .or_insert(*transaction_id);
6904                }
6905            }
6906        }
6907
6908        self.undo_stack.truncate(new_len);
6909        self.undo_stack.last().map(|t| t.id)
6910    }
6911}
6912
6913impl Excerpt {
6914    fn new(
6915        id: ExcerptId,
6916        locator: Locator,
6917        buffer_id: BufferId,
6918        buffer: BufferSnapshot,
6919        range: ExcerptRange<text::Anchor>,
6920        has_trailing_newline: bool,
6921    ) -> Self {
6922        Excerpt {
6923            id,
6924            locator,
6925            max_buffer_row: range.context.end.to_point(&buffer).row,
6926            text_summary: buffer
6927                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6928            buffer_id,
6929            buffer,
6930            range,
6931            has_trailing_newline,
6932        }
6933    }
6934
6935    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6936        let content_start = self.range.context.start.to_offset(&self.buffer);
6937        let chunks_start = content_start + range.start;
6938        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6939
6940        let footer_height = if self.has_trailing_newline
6941            && range.start <= self.text_summary.len
6942            && range.end > self.text_summary.len
6943        {
6944            1
6945        } else {
6946            0
6947        };
6948
6949        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6950
6951        ExcerptChunks {
6952            excerpt_id: self.id,
6953            content_chunks,
6954            footer_height,
6955        }
6956    }
6957
6958    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6959        let content_start = self.range.context.start.to_offset(&self.buffer);
6960        let chunks_start = content_start + range.start;
6961        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6962        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6963        excerpt_chunks.footer_height = if self.has_trailing_newline
6964            && range.start <= self.text_summary.len
6965            && range.end > self.text_summary.len
6966        {
6967            1
6968        } else {
6969            0
6970        };
6971    }
6972
6973    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6974        if text_anchor
6975            .cmp(&self.range.context.start, &self.buffer)
6976            .is_lt()
6977        {
6978            self.range.context.start
6979        } else if text_anchor
6980            .cmp(&self.range.context.end, &self.buffer)
6981            .is_gt()
6982        {
6983            self.range.context.end
6984        } else {
6985            text_anchor
6986        }
6987    }
6988
6989    fn contains(&self, anchor: &Anchor) -> bool {
6990        Some(self.buffer_id) == anchor.buffer_id
6991            && self
6992                .range
6993                .context
6994                .start
6995                .cmp(&anchor.text_anchor, &self.buffer)
6996                .is_le()
6997            && self
6998                .range
6999                .context
7000                .end
7001                .cmp(&anchor.text_anchor, &self.buffer)
7002                .is_ge()
7003    }
7004
7005    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7006    fn buffer_start_offset(&self) -> usize {
7007        self.range.context.start.to_offset(&self.buffer)
7008    }
7009
7010    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7011    fn buffer_end_offset(&self) -> usize {
7012        self.buffer_start_offset() + self.text_summary.len
7013    }
7014}
7015
7016impl<'a> MultiBufferExcerpt<'a> {
7017    pub fn id(&self) -> ExcerptId {
7018        self.excerpt.id
7019    }
7020
7021    pub fn buffer_id(&self) -> BufferId {
7022        self.excerpt.buffer_id
7023    }
7024
7025    pub fn start_anchor(&self) -> Anchor {
7026        Anchor {
7027            buffer_id: Some(self.excerpt.buffer_id),
7028            excerpt_id: self.excerpt.id,
7029            text_anchor: self.excerpt.range.context.start,
7030            diff_base_anchor: None,
7031        }
7032    }
7033
7034    pub fn end_anchor(&self) -> Anchor {
7035        Anchor {
7036            buffer_id: Some(self.excerpt.buffer_id),
7037            excerpt_id: self.excerpt.id,
7038            text_anchor: self.excerpt.range.context.end,
7039            diff_base_anchor: None,
7040        }
7041    }
7042
7043    pub fn buffer(&self) -> &'a BufferSnapshot {
7044        &self.excerpt.buffer
7045    }
7046
7047    pub fn buffer_range(&self) -> Range<usize> {
7048        self.buffer_offset
7049            ..self
7050                .excerpt
7051                .range
7052                .context
7053                .end
7054                .to_offset(&self.excerpt.buffer.text)
7055    }
7056
7057    pub fn start_offset(&self) -> usize {
7058        self.offset
7059    }
7060
7061    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7062    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
7063        self.map_range_to_buffer(offset..offset).start
7064    }
7065
7066    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7067    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
7068        self.diff_transforms
7069            .seek(&OutputDimension(range.start), Bias::Right);
7070        let start = self.map_offset_to_buffer_internal(range.start);
7071        let end = if range.end > range.start {
7072            self.diff_transforms
7073                .seek_forward(&OutputDimension(range.end), Bias::Right);
7074            self.map_offset_to_buffer_internal(range.end)
7075        } else {
7076            start
7077        };
7078        start..end
7079    }
7080
7081    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
7082        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
7083        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7084            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
7085        };
7086        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
7087        self.buffer_offset + offset_in_excerpt
7088    }
7089
7090    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7091    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
7092        self.map_range_from_buffer(buffer_offset..buffer_offset)
7093            .start
7094    }
7095
7096    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7097    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
7098        if buffer_range.start < self.buffer_offset {
7099            log::warn!(
7100                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7101            );
7102            return buffer_range;
7103        }
7104        let overshoot = buffer_range.start - self.buffer_offset;
7105        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7106        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
7107        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
7108            log::warn!(
7109                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7110            );
7111            return buffer_range;
7112        }
7113        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7114        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7115
7116        let end = if buffer_range.end > buffer_range.start {
7117            let overshoot = buffer_range.end - self.buffer_offset;
7118            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7119            self.diff_transforms
7120                .seek_forward(&excerpt_offset, Bias::Right);
7121            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7122            self.diff_transforms.start().output_dimension.0 + overshoot
7123        } else {
7124            start
7125        };
7126
7127        start..end
7128    }
7129
7130    /// Returns true if the entirety of the given range is in the buffer's excerpt
7131    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
7132        range.start >= self.excerpt.buffer_start_offset()
7133            && range.end <= self.excerpt.buffer_end_offset()
7134    }
7135
7136    pub fn max_buffer_row(&self) -> u32 {
7137        self.excerpt.max_buffer_row
7138    }
7139}
7140
7141impl ExcerptId {
7142    pub fn min() -> Self {
7143        Self(0)
7144    }
7145
7146    pub fn max() -> Self {
7147        Self(usize::MAX)
7148    }
7149
7150    pub fn to_proto(self) -> u64 {
7151        self.0 as _
7152    }
7153
7154    pub fn from_proto(proto: u64) -> Self {
7155        Self(proto as _)
7156    }
7157
7158    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7159        let a = snapshot.excerpt_locator_for_id(*self);
7160        let b = snapshot.excerpt_locator_for_id(*other);
7161        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7162    }
7163}
7164
7165impl From<ExcerptId> for usize {
7166    fn from(val: ExcerptId) -> Self {
7167        val.0
7168    }
7169}
7170
7171impl fmt::Debug for Excerpt {
7172    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7173        f.debug_struct("Excerpt")
7174            .field("id", &self.id)
7175            .field("locator", &self.locator)
7176            .field("buffer_id", &self.buffer_id)
7177            .field("range", &self.range)
7178            .field("text_summary", &self.text_summary)
7179            .field("has_trailing_newline", &self.has_trailing_newline)
7180            .finish()
7181    }
7182}
7183
7184impl sum_tree::Item for Excerpt {
7185    type Summary = ExcerptSummary;
7186
7187    fn summary(&self, _cx: &()) -> Self::Summary {
7188        let mut text = self.text_summary;
7189        if self.has_trailing_newline {
7190            text += TextSummary::from("\n");
7191        }
7192        ExcerptSummary {
7193            excerpt_id: self.id,
7194            excerpt_locator: self.locator.clone(),
7195            widest_line_number: self.max_buffer_row,
7196            text,
7197        }
7198    }
7199}
7200
7201impl sum_tree::Item for ExcerptIdMapping {
7202    type Summary = ExcerptId;
7203
7204    fn summary(&self, _cx: &()) -> Self::Summary {
7205        self.id
7206    }
7207}
7208
7209impl sum_tree::KeyedItem for ExcerptIdMapping {
7210    type Key = ExcerptId;
7211
7212    fn key(&self) -> Self::Key {
7213        self.id
7214    }
7215}
7216
7217impl DiffTransform {
7218    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7219        match self {
7220            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7221            DiffTransform::BufferContent {
7222                inserted_hunk_info, ..
7223            } => *inserted_hunk_info,
7224        }
7225    }
7226}
7227
7228impl sum_tree::Item for DiffTransform {
7229    type Summary = DiffTransformSummary;
7230
7231    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7232        match self {
7233            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7234                input: *summary,
7235                output: *summary,
7236            },
7237            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7238                input: TextSummary::default(),
7239                output: *summary,
7240            },
7241        }
7242    }
7243}
7244
7245impl DiffTransformSummary {
7246    fn excerpt_len(&self) -> ExcerptOffset {
7247        ExcerptOffset::new(self.input.len)
7248    }
7249}
7250
7251impl sum_tree::Summary for DiffTransformSummary {
7252    type Context = ();
7253
7254    fn zero(_: &Self::Context) -> Self {
7255        DiffTransformSummary {
7256            input: TextSummary::default(),
7257            output: TextSummary::default(),
7258        }
7259    }
7260
7261    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7262        self.input += &summary.input;
7263        self.output += &summary.output;
7264    }
7265}
7266
7267impl sum_tree::Summary for ExcerptId {
7268    type Context = ();
7269
7270    fn zero(_cx: &()) -> Self {
7271        Default::default()
7272    }
7273
7274    fn add_summary(&mut self, other: &Self, _: &()) {
7275        *self = *other;
7276    }
7277}
7278
7279impl sum_tree::Summary for ExcerptSummary {
7280    type Context = ();
7281
7282    fn zero(_cx: &()) -> Self {
7283        Default::default()
7284    }
7285
7286    fn add_summary(&mut self, summary: &Self, _: &()) {
7287        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7288        self.excerpt_locator = summary.excerpt_locator.clone();
7289        Summary::add_summary(&mut self.text, &summary.text, &());
7290        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7291    }
7292}
7293
7294impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7295    fn zero(_cx: &()) -> Self {
7296        Default::default()
7297    }
7298
7299    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7300        self.value += summary.text.len;
7301    }
7302}
7303
7304impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7305    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7306        Ord::cmp(&self.value, &cursor_location.text.len)
7307    }
7308}
7309
7310impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7311    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7312        Ord::cmp(&Some(self), cursor_location)
7313    }
7314}
7315
7316impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7317    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7318        Ord::cmp(self, &cursor_location.excerpt_locator)
7319    }
7320}
7321
7322impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7323    fn zero(_cx: &()) -> Self {
7324        Default::default()
7325    }
7326
7327    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7328        self.value += summary.text.lines;
7329    }
7330}
7331
7332impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7333    for ExcerptDimension<D>
7334{
7335    fn zero(_: &()) -> Self {
7336        ExcerptDimension(D::default())
7337    }
7338
7339    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7340        self.0.add_assign(&D::from_text_summary(&summary.text))
7341    }
7342}
7343
7344impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7345    fn zero(_cx: &()) -> Self {
7346        Default::default()
7347    }
7348
7349    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7350        *self = Some(&summary.excerpt_locator);
7351    }
7352}
7353
7354impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7355    fn zero(_cx: &()) -> Self {
7356        Default::default()
7357    }
7358
7359    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7360        *self = Some(summary.excerpt_id);
7361    }
7362}
7363
7364#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7365struct ExcerptDimension<T>(T);
7366
7367#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7368struct OutputDimension<T>(T);
7369
7370impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7371    fn zero(_: &()) -> Self {
7372        ExcerptOffset::new(0)
7373    }
7374
7375    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7376        self.value += summary.input.len;
7377    }
7378}
7379
7380impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7381    fn zero(_: &()) -> Self {
7382        ExcerptPoint::new(0, 0)
7383    }
7384
7385    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7386        self.value += summary.input.lines;
7387    }
7388}
7389
7390impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7391    for ExcerptDimension<D>
7392{
7393    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7394        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7395    }
7396}
7397
7398impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7399    for ExcerptDimension<D>
7400{
7401    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7402        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7403    }
7404}
7405
7406impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7407    fn zero(_: &()) -> Self {
7408        ExcerptDimension(D::default())
7409    }
7410
7411    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7412        self.0.add_assign(&D::from_text_summary(&summary.input))
7413    }
7414}
7415
7416impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7417    for OutputDimension<D>
7418{
7419    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7420        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7421    }
7422}
7423
7424impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7425    fn zero(_: &()) -> Self {
7426        OutputDimension(D::default())
7427    }
7428
7429    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7430        self.0.add_assign(&D::from_text_summary(&summary.output))
7431    }
7432}
7433
7434impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7435    fn zero(_: &()) -> Self {
7436        TextSummary::default()
7437    }
7438
7439    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7440        *self += summary.output
7441    }
7442}
7443
7444impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7445    fn zero(_: &()) -> Self {
7446        0
7447    }
7448
7449    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7450        *self += summary.output.len
7451    }
7452}
7453
7454impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7455    fn zero(_: &()) -> Self {
7456        Point::new(0, 0)
7457    }
7458
7459    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7460        *self += summary.output.lines
7461    }
7462}
7463
7464impl MultiBufferRows<'_> {
7465    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7466        self.point = Point::new(row, 0);
7467        self.cursor.seek(&self.point);
7468    }
7469}
7470
7471impl Iterator for MultiBufferRows<'_> {
7472    type Item = RowInfo;
7473
7474    fn next(&mut self) -> Option<Self::Item> {
7475        if self.is_empty && self.point.row == 0 {
7476            self.point += Point::new(1, 0);
7477            return Some(RowInfo {
7478                buffer_id: None,
7479                buffer_row: Some(0),
7480                multibuffer_row: Some(MultiBufferRow(0)),
7481                diff_status: None,
7482                expand_info: None,
7483            });
7484        }
7485
7486        let mut region = self.cursor.region()?;
7487        while self.point >= region.range.end {
7488            self.cursor.next();
7489            if let Some(next_region) = self.cursor.region() {
7490                region = next_region;
7491            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7492                let multibuffer_row = MultiBufferRow(self.point.row);
7493                let last_excerpt = self
7494                    .cursor
7495                    .excerpts
7496                    .item()
7497                    .or(self.cursor.excerpts.prev_item())?;
7498                let last_row = last_excerpt
7499                    .range
7500                    .context
7501                    .end
7502                    .to_point(&last_excerpt.buffer)
7503                    .row;
7504
7505                let first_row = last_excerpt
7506                    .range
7507                    .context
7508                    .start
7509                    .to_point(&last_excerpt.buffer)
7510                    .row;
7511
7512                let expand_info = if self.is_singleton {
7513                    None
7514                } else {
7515                    let needs_expand_up = first_row == last_row
7516                        && last_row > 0
7517                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7518                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7519
7520                    if needs_expand_up && needs_expand_down {
7521                        Some(ExpandExcerptDirection::UpAndDown)
7522                    } else if needs_expand_up {
7523                        Some(ExpandExcerptDirection::Up)
7524                    } else if needs_expand_down {
7525                        Some(ExpandExcerptDirection::Down)
7526                    } else {
7527                        None
7528                    }
7529                    .map(|direction| ExpandInfo {
7530                        direction,
7531                        excerpt_id: last_excerpt.id,
7532                    })
7533                };
7534                self.point += Point::new(1, 0);
7535                return Some(RowInfo {
7536                    buffer_id: Some(last_excerpt.buffer_id),
7537                    buffer_row: Some(last_row),
7538                    multibuffer_row: Some(multibuffer_row),
7539                    diff_status: None,
7540                    expand_info,
7541                });
7542            } else {
7543                return None;
7544            };
7545        }
7546
7547        let overshoot = self.point - region.range.start;
7548        let buffer_point = region.buffer_range.start + overshoot;
7549        let expand_info = if self.is_singleton {
7550            None
7551        } else {
7552            let needs_expand_up = self.point.row == region.range.start.row
7553                && self.cursor.is_at_start_of_excerpt()
7554                && buffer_point.row > 0;
7555            let needs_expand_down = (region.excerpt.has_trailing_newline
7556                && self.point.row + 1 == region.range.end.row
7557                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7558                && self.cursor.is_at_end_of_excerpt()
7559                && buffer_point.row < region.buffer.max_point().row;
7560
7561            if needs_expand_up && needs_expand_down {
7562                Some(ExpandExcerptDirection::UpAndDown)
7563            } else if needs_expand_up {
7564                Some(ExpandExcerptDirection::Up)
7565            } else if needs_expand_down {
7566                Some(ExpandExcerptDirection::Down)
7567            } else {
7568                None
7569            }
7570            .map(|direction| ExpandInfo {
7571                direction,
7572                excerpt_id: region.excerpt.id,
7573            })
7574        };
7575
7576        let result = Some(RowInfo {
7577            buffer_id: Some(region.buffer.remote_id()),
7578            buffer_row: Some(buffer_point.row),
7579            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7580            diff_status: region
7581                .diff_hunk_status
7582                .filter(|_| self.point < region.range.end),
7583            expand_info,
7584        });
7585        self.point += Point::new(1, 0);
7586        result
7587    }
7588}
7589
7590impl<'a> MultiBufferChunks<'a> {
7591    pub fn offset(&self) -> usize {
7592        self.range.start
7593    }
7594
7595    pub fn seek(&mut self, range: Range<usize>) {
7596        self.diff_transforms.seek(&range.end, Bias::Right);
7597        let mut excerpt_end = self.diff_transforms.start().1;
7598        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7599            let overshoot = range.end - self.diff_transforms.start().0;
7600            excerpt_end.value += overshoot;
7601        }
7602
7603        self.diff_transforms.seek(&range.start, Bias::Right);
7604        let mut excerpt_start = self.diff_transforms.start().1;
7605        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7606            let overshoot = range.start - self.diff_transforms.start().0;
7607            excerpt_start.value += overshoot;
7608        }
7609
7610        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7611        self.buffer_chunk.take();
7612        self.range = range;
7613    }
7614
7615    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7616        self.excerpt_offset_range = new_range.clone();
7617        self.excerpts.seek(&new_range.start, Bias::Right);
7618        if let Some(excerpt) = self.excerpts.item() {
7619            let excerpt_start = *self.excerpts.start();
7620            if let Some(excerpt_chunks) = self
7621                .excerpt_chunks
7622                .as_mut()
7623                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7624            {
7625                excerpt.seek_chunks(
7626                    excerpt_chunks,
7627                    (self.excerpt_offset_range.start - excerpt_start).value
7628                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7629                );
7630            } else {
7631                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7632                    (self.excerpt_offset_range.start - excerpt_start).value
7633                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7634                    self.language_aware,
7635                ));
7636            }
7637        } else {
7638            self.excerpt_chunks = None;
7639        }
7640    }
7641
7642    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7643        loop {
7644            if self.excerpt_offset_range.is_empty() {
7645                return None;
7646            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7647                self.excerpt_offset_range.start.value += chunk.text.len();
7648                return Some(chunk);
7649            } else {
7650                self.excerpts.next();
7651                let excerpt = self.excerpts.item()?;
7652                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7653                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7654                    self.language_aware,
7655                ));
7656            }
7657        }
7658    }
7659}
7660
7661impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7662    type Item = &'a str;
7663
7664    fn next(&mut self) -> Option<Self::Item> {
7665        let mut region = self.cursor.region()?;
7666        if self.offset == region.range.start {
7667            self.cursor.prev();
7668            region = self.cursor.region()?;
7669            let start_overshoot = self.start.saturating_sub(region.range.start);
7670            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7671                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7672            ));
7673        }
7674
7675        if self.offset == region.range.end && region.has_trailing_newline {
7676            self.offset -= 1;
7677            Some("\n")
7678        } else {
7679            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7680            self.offset -= chunk.len();
7681            Some(chunk)
7682        }
7683    }
7684}
7685
7686impl<'a> Iterator for MultiBufferChunks<'a> {
7687    type Item = Chunk<'a>;
7688
7689    fn next(&mut self) -> Option<Chunk<'a>> {
7690        if self.range.start >= self.range.end {
7691            return None;
7692        }
7693        if self.range.start == self.diff_transforms.end().0 {
7694            self.diff_transforms.next();
7695        }
7696
7697        let diff_transform_start = self.diff_transforms.start().0;
7698        let diff_transform_end = self.diff_transforms.end().0;
7699        debug_assert!(self.range.start < diff_transform_end);
7700
7701        let diff_transform = self.diff_transforms.item()?;
7702        match diff_transform {
7703            DiffTransform::BufferContent { .. } => {
7704                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7705                    chunk
7706                } else {
7707                    let chunk = self.next_excerpt_chunk().unwrap();
7708                    self.buffer_chunk.insert(chunk)
7709                };
7710
7711                let chunk_end = self.range.start + chunk.text.len();
7712                let diff_transform_end = diff_transform_end.min(self.range.end);
7713
7714                if diff_transform_end < chunk_end {
7715                    let (before, after) =
7716                        chunk.text.split_at(diff_transform_end - self.range.start);
7717                    self.range.start = diff_transform_end;
7718                    chunk.text = after;
7719                    Some(Chunk {
7720                        text: before,
7721                        ..chunk.clone()
7722                    })
7723                } else {
7724                    self.range.start = chunk_end;
7725                    self.buffer_chunk.take()
7726                }
7727            }
7728            DiffTransform::DeletedHunk {
7729                buffer_id,
7730                base_text_byte_range,
7731                has_trailing_newline,
7732                ..
7733            } => {
7734                let base_text_start =
7735                    base_text_byte_range.start + self.range.start - diff_transform_start;
7736                let base_text_end =
7737                    base_text_byte_range.start + self.range.end - diff_transform_start;
7738                let base_text_end = base_text_end.min(base_text_byte_range.end);
7739
7740                let mut chunks = if let Some((_, mut chunks)) = self
7741                    .diff_base_chunks
7742                    .take()
7743                    .filter(|(id, _)| id == buffer_id)
7744                {
7745                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7746                    {
7747                        chunks.seek(base_text_start..base_text_end);
7748                    }
7749                    chunks
7750                } else {
7751                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7752                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7753                };
7754
7755                let chunk = if let Some(chunk) = chunks.next() {
7756                    self.range.start += chunk.text.len();
7757                    self.diff_base_chunks = Some((*buffer_id, chunks));
7758                    chunk
7759                } else {
7760                    debug_assert!(has_trailing_newline);
7761                    self.range.start += "\n".len();
7762                    Chunk {
7763                        text: "\n",
7764                        ..Default::default()
7765                    }
7766                };
7767                Some(chunk)
7768            }
7769        }
7770    }
7771}
7772
7773impl MultiBufferBytes<'_> {
7774    fn consume(&mut self, len: usize) {
7775        self.range.start += len;
7776        self.chunk = &self.chunk[len..];
7777
7778        if !self.range.is_empty() && self.chunk.is_empty() {
7779            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7780                self.chunk = chunk;
7781            } else if self.has_trailing_newline {
7782                self.has_trailing_newline = false;
7783                self.chunk = b"\n";
7784            } else {
7785                self.cursor.next();
7786                if let Some(region) = self.cursor.region() {
7787                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7788                        region.buffer_range.start
7789                            ..(region.buffer_range.start + self.range.end - region.range.start)
7790                                .min(region.buffer_range.end),
7791                    );
7792                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7793                    self.excerpt_bytes = Some(excerpt_bytes);
7794                    self.has_trailing_newline =
7795                        region.has_trailing_newline && self.range.end >= region.range.end;
7796                    if self.chunk.is_empty() && self.has_trailing_newline {
7797                        self.has_trailing_newline = false;
7798                        self.chunk = b"\n";
7799                    }
7800                }
7801            }
7802        }
7803    }
7804}
7805
7806impl<'a> Iterator for MultiBufferBytes<'a> {
7807    type Item = &'a [u8];
7808
7809    fn next(&mut self) -> Option<Self::Item> {
7810        let chunk = self.chunk;
7811        if chunk.is_empty() {
7812            None
7813        } else {
7814            self.consume(chunk.len());
7815            Some(chunk)
7816        }
7817    }
7818}
7819
7820impl io::Read for MultiBufferBytes<'_> {
7821    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7822        let len = cmp::min(buf.len(), self.chunk.len());
7823        buf[..len].copy_from_slice(&self.chunk[..len]);
7824        if len > 0 {
7825            self.consume(len);
7826        }
7827        Ok(len)
7828    }
7829}
7830
7831impl io::Read for ReversedMultiBufferBytes<'_> {
7832    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7833        let len = cmp::min(buf.len(), self.chunk.len());
7834        buf[..len].copy_from_slice(&self.chunk[..len]);
7835        buf[..len].reverse();
7836        if len > 0 {
7837            self.range.end -= len;
7838            self.chunk = &self.chunk[..self.chunk.len() - len];
7839            if !self.range.is_empty()
7840                && self.chunk.is_empty()
7841                && let Some(chunk) = self.chunks.next()
7842            {
7843                self.chunk = chunk.as_bytes();
7844            }
7845        }
7846        Ok(len)
7847    }
7848}
7849
7850impl<'a> Iterator for ExcerptChunks<'a> {
7851    type Item = Chunk<'a>;
7852
7853    fn next(&mut self) -> Option<Self::Item> {
7854        if let Some(chunk) = self.content_chunks.next() {
7855            return Some(chunk);
7856        }
7857
7858        if self.footer_height > 0 {
7859            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7860            self.footer_height = 0;
7861            return Some(Chunk {
7862                text,
7863                ..Default::default()
7864            });
7865        }
7866
7867        None
7868    }
7869}
7870
7871impl ToOffset for Point {
7872    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7873        snapshot.point_to_offset(*self)
7874    }
7875}
7876
7877impl ToOffset for usize {
7878    #[track_caller]
7879    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7880        assert!(
7881            *self <= snapshot.len(),
7882            "offset {} is greater than the snapshot.len() {}",
7883            *self,
7884            snapshot.len(),
7885        );
7886        *self
7887    }
7888}
7889
7890impl ToOffset for OffsetUtf16 {
7891    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7892        snapshot.offset_utf16_to_offset(*self)
7893    }
7894}
7895
7896impl ToOffset for PointUtf16 {
7897    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7898        snapshot.point_utf16_to_offset(*self)
7899    }
7900}
7901
7902impl ToOffsetUtf16 for OffsetUtf16 {
7903    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7904        *self
7905    }
7906}
7907
7908impl ToOffsetUtf16 for usize {
7909    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7910        snapshot.offset_to_offset_utf16(*self)
7911    }
7912}
7913
7914impl ToPoint for usize {
7915    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7916        snapshot.offset_to_point(*self)
7917    }
7918}
7919
7920impl ToPoint for Point {
7921    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7922        *self
7923    }
7924}
7925
7926impl ToPointUtf16 for usize {
7927    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7928        snapshot.offset_to_point_utf16(*self)
7929    }
7930}
7931
7932impl ToPointUtf16 for Point {
7933    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7934        snapshot.point_to_point_utf16(*self)
7935    }
7936}
7937
7938impl ToPointUtf16 for PointUtf16 {
7939    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7940        *self
7941    }
7942}
7943
7944impl From<ExcerptId> for EntityId {
7945    fn from(id: ExcerptId) -> Self {
7946        EntityId::from(id.0 as u64)
7947    }
7948}