multi_buffer.rs

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