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