multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{Result, anyhow};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  17use itertools::Itertools;
  18use language::{
  19    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  20    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  21    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  22    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  23    Unclipped,
  24    language_settings::{IndentGuideSettings, LanguageSettings, language_settings},
  25};
  26
  27use rope::DimensionPair;
  28use smallvec::SmallVec;
  29use smol::future::yield_now;
  30use std::{
  31    any::type_name,
  32    borrow::Cow,
  33    cell::{Cell, Ref, RefCell},
  34    cmp, fmt,
  35    future::Future,
  36    io,
  37    iter::{self, FromIterator},
  38    mem,
  39    ops::{Range, RangeBounds, Sub},
  40    path::{Path, PathBuf},
  41    rc::Rc,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, Dimension, SumTree, Summary, TreeMap};
  47use text::{
  48    BufferId, Edit, LineIndent, TextSummary,
  49    locator::Locator,
  50    subscription::{Subscription, Topic},
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  72    diffs: HashMap<BufferId, DiffState>,
  73    // all_diff_hunks_expanded: bool,
  74    subscriptions: Topic,
  75    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  76    singleton: bool,
  77    history: History,
  78    title: Option<String>,
  79    capability: Capability,
  80    buffer_changed_since_sync: Rc<Cell<bool>>,
  81}
  82
  83#[derive(Clone, Debug, PartialEq, Eq)]
  84pub enum MultiOrSingleBufferOffsetRange {
  85    Single(Range<usize>),
  86    Multi(Range<usize>),
  87}
  88
  89#[derive(Clone, Debug, PartialEq, Eq)]
  90pub enum Event {
  91    ExcerptsAdded {
  92        buffer: Entity<Buffer>,
  93        predecessor: ExcerptId,
  94        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  95    },
  96    ExcerptsRemoved {
  97        ids: Vec<ExcerptId>,
  98        removed_buffer_ids: Vec<BufferId>,
  99    },
 100    ExcerptsExpanded {
 101        ids: Vec<ExcerptId>,
 102    },
 103    ExcerptsEdited {
 104        excerpt_ids: Vec<ExcerptId>,
 105        buffer_ids: Vec<BufferId>,
 106    },
 107    DiffHunksToggled,
 108    Edited {
 109        singleton_buffer_edited: bool,
 110        edited_buffer: Option<Entity<Buffer>>,
 111    },
 112    TransactionUndone {
 113        transaction_id: TransactionId,
 114    },
 115    Reloaded,
 116    ReloadNeeded,
 117
 118    LanguageChanged(BufferId),
 119    CapabilityChanged,
 120    Reparsed(BufferId),
 121    Saved,
 122    FileHandleChanged,
 123    Closed,
 124    Discarded,
 125    DirtyChanged,
 126    DiagnosticsUpdated,
 127    BufferDiffChanged,
 128}
 129
 130/// A diff hunk, representing a range of consequent lines in a multibuffer.
 131#[derive(Debug, Clone, PartialEq, Eq)]
 132pub struct MultiBufferDiffHunk {
 133    /// The row range in the multibuffer where this diff hunk appears.
 134    pub row_range: Range<MultiBufferRow>,
 135    /// The buffer ID that this hunk belongs to.
 136    pub buffer_id: BufferId,
 137    /// The range of the underlying buffer that this hunk corresponds to.
 138    pub buffer_range: Range<text::Anchor>,
 139    /// The excerpt that contains the diff hunk.
 140    pub excerpt_id: ExcerptId,
 141    /// The range within the buffer's diff base that this hunk corresponds to.
 142    pub diff_base_byte_range: Range<usize>,
 143    /// Whether or not this hunk also appears in the 'secondary diff'.
 144    pub secondary_status: DiffHunkSecondaryStatus,
 145}
 146
 147impl MultiBufferDiffHunk {
 148    pub fn status(&self) -> DiffHunkStatus {
 149        let kind = if self.buffer_range.start == self.buffer_range.end {
 150            DiffHunkStatusKind::Deleted
 151        } else if self.diff_base_byte_range.is_empty() {
 152            DiffHunkStatusKind::Added
 153        } else {
 154            DiffHunkStatusKind::Modified
 155        };
 156        DiffHunkStatus {
 157            kind,
 158            secondary: self.secondary_status,
 159        }
 160    }
 161
 162    pub fn is_created_file(&self) -> bool {
 163        self.diff_base_byte_range == (0..0)
 164            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 165    }
 166
 167    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 168        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 169        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 170        start..end
 171    }
 172}
 173
 174#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 175pub struct PathKey {
 176    namespace: u32,
 177    path: Arc<Path>,
 178}
 179
 180impl PathKey {
 181    pub fn namespaced(namespace: u32, path: Arc<Path>) -> Self {
 182        Self { namespace, path }
 183    }
 184
 185    pub fn for_buffer(buffer: &Entity<Buffer>, cx: &App) -> Self {
 186        if let Some(file) = buffer.read(cx).file() {
 187            Self::namespaced(1, Arc::from(file.full_path(cx)))
 188        } else {
 189            Self::namespaced(0, Arc::from(PathBuf::from(buffer.entity_id().to_string())))
 190        }
 191    }
 192
 193    pub fn path(&self) -> &Arc<Path> {
 194        &self.path
 195    }
 196}
 197
 198pub type MultiBufferPoint = Point;
 199type ExcerptOffset = TypedOffset<Excerpt>;
 200type ExcerptPoint = TypedPoint<Excerpt>;
 201
 202#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 203#[serde(transparent)]
 204pub struct MultiBufferRow(pub u32);
 205
 206impl MultiBufferRow {
 207    pub const MIN: Self = Self(0);
 208    pub const MAX: Self = Self(u32::MAX);
 209}
 210
 211impl std::ops::Add<usize> for MultiBufferRow {
 212    type Output = Self;
 213
 214    fn add(self, rhs: usize) -> Self::Output {
 215        MultiBufferRow(self.0 + rhs as u32)
 216    }
 217}
 218
 219#[derive(Clone)]
 220struct History {
 221    next_transaction_id: TransactionId,
 222    undo_stack: Vec<Transaction>,
 223    redo_stack: Vec<Transaction>,
 224    transaction_depth: usize,
 225    group_interval: Duration,
 226}
 227
 228#[derive(Clone)]
 229struct Transaction {
 230    id: TransactionId,
 231    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 232    first_edit_at: Instant,
 233    last_edit_at: Instant,
 234    suppress_grouping: bool,
 235}
 236
 237pub trait ToOffset: 'static + fmt::Debug {
 238    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 239}
 240
 241pub trait ToOffsetUtf16: 'static + fmt::Debug {
 242    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 243}
 244
 245pub trait ToPoint: 'static + fmt::Debug {
 246    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 247}
 248
 249pub trait ToPointUtf16: 'static + fmt::Debug {
 250    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 251}
 252
 253struct BufferState {
 254    buffer: Entity<Buffer>,
 255    last_version: clock::Global,
 256    last_non_text_state_update_count: usize,
 257    excerpts: Vec<Locator>,
 258    _subscriptions: [gpui::Subscription; 2],
 259}
 260
 261struct DiffState {
 262    diff: Entity<BufferDiff>,
 263    _subscription: gpui::Subscription,
 264}
 265
 266impl DiffState {
 267    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 268        DiffState {
 269            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 270                BufferDiffEvent::DiffChanged { changed_range } => {
 271                    if let Some(changed_range) = changed_range.clone() {
 272                        this.buffer_diff_changed(diff, changed_range, cx)
 273                    }
 274                    cx.emit(Event::BufferDiffChanged);
 275                }
 276                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 277                _ => {}
 278            }),
 279            diff,
 280        }
 281    }
 282}
 283
 284/// The contents of a [`MultiBuffer`] at a single point in time.
 285#[derive(Clone, Default)]
 286pub struct MultiBufferSnapshot {
 287    singleton: bool,
 288    excerpts: SumTree<Excerpt>,
 289    excerpt_ids: SumTree<ExcerptIdMapping>,
 290    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 291    diff_transforms: SumTree<DiffTransform>,
 292    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 293    trailing_excerpt_update_count: usize,
 294    all_diff_hunks_expanded: bool,
 295    non_text_state_update_count: usize,
 296    edit_count: usize,
 297    is_dirty: bool,
 298    has_deleted_file: bool,
 299    has_conflict: bool,
 300    show_headers: bool,
 301}
 302
 303#[derive(Debug, Clone)]
 304enum DiffTransform {
 305    BufferContent {
 306        summary: TextSummary,
 307        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 308    },
 309    DeletedHunk {
 310        summary: TextSummary,
 311        buffer_id: BufferId,
 312        hunk_info: DiffTransformHunkInfo,
 313        base_text_byte_range: Range<usize>,
 314        has_trailing_newline: bool,
 315    },
 316}
 317
 318#[derive(Clone, Copy, Debug)]
 319struct DiffTransformHunkInfo {
 320    excerpt_id: ExcerptId,
 321    hunk_start_anchor: text::Anchor,
 322    hunk_secondary_status: DiffHunkSecondaryStatus,
 323}
 324
 325impl Eq for DiffTransformHunkInfo {}
 326
 327impl PartialEq for DiffTransformHunkInfo {
 328    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 329        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 330    }
 331}
 332
 333impl std::hash::Hash for DiffTransformHunkInfo {
 334    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 335        self.excerpt_id.hash(state);
 336        self.hunk_start_anchor.hash(state);
 337    }
 338}
 339
 340#[derive(Clone)]
 341pub struct ExcerptInfo {
 342    pub id: ExcerptId,
 343    pub buffer: BufferSnapshot,
 344    pub buffer_id: BufferId,
 345    pub range: ExcerptRange<text::Anchor>,
 346    pub end_row: MultiBufferRow,
 347}
 348
 349impl std::fmt::Debug for ExcerptInfo {
 350    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 351        f.debug_struct(type_name::<Self>())
 352            .field("id", &self.id)
 353            .field("buffer_id", &self.buffer_id)
 354            .field("path", &self.buffer.file().map(|f| f.path()))
 355            .field("range", &self.range)
 356            .finish()
 357    }
 358}
 359
 360/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 361#[derive(Debug)]
 362pub struct ExcerptBoundary {
 363    pub prev: Option<ExcerptInfo>,
 364    pub next: ExcerptInfo,
 365    /// The row in the `MultiBuffer` where the boundary is located
 366    pub row: MultiBufferRow,
 367}
 368
 369impl ExcerptBoundary {
 370    pub fn starts_new_buffer(&self) -> bool {
 371        match (self.prev.as_ref(), &self.next) {
 372            (None, _) => true,
 373            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 374        }
 375    }
 376}
 377
 378#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 379pub struct ExpandInfo {
 380    pub direction: ExpandExcerptDirection,
 381    pub excerpt_id: ExcerptId,
 382}
 383
 384#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 385pub struct RowInfo {
 386    pub buffer_id: Option<BufferId>,
 387    pub buffer_row: Option<u32>,
 388    pub multibuffer_row: Option<MultiBufferRow>,
 389    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 390    pub expand_info: Option<ExpandInfo>,
 391}
 392
 393/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 394#[derive(Clone)]
 395struct Excerpt {
 396    /// The unique identifier for this excerpt
 397    id: ExcerptId,
 398    /// The location of the excerpt in the [`MultiBuffer`]
 399    locator: Locator,
 400    /// The buffer being excerpted
 401    buffer_id: BufferId,
 402    /// A snapshot of the buffer being excerpted
 403    buffer: BufferSnapshot,
 404    /// The range of the buffer to be shown in the excerpt
 405    range: ExcerptRange<text::Anchor>,
 406    /// The last row in the excerpted slice of the buffer
 407    max_buffer_row: BufferRow,
 408    /// A summary of the text in the excerpt
 409    text_summary: TextSummary,
 410    has_trailing_newline: bool,
 411}
 412
 413/// A public view into an `Excerpt` in a [`MultiBuffer`].
 414///
 415/// Contains methods for getting the [`Buffer`] of the excerpt,
 416/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 417#[derive(Clone)]
 418pub struct MultiBufferExcerpt<'a> {
 419    excerpt: &'a Excerpt,
 420    diff_transforms: sum_tree::Cursor<'a, DiffTransform, DiffTransforms<usize>>,
 421    offset: usize,
 422    excerpt_offset: ExcerptDimension<usize>,
 423    buffer_offset: usize,
 424}
 425
 426#[derive(Clone, Debug)]
 427struct ExcerptIdMapping {
 428    id: ExcerptId,
 429    locator: Locator,
 430}
 431
 432/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 433/// These ranges are relative to the buffer itself
 434#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 435pub struct ExcerptRange<T> {
 436    /// The full range of text to be shown in the excerpt.
 437    pub context: Range<T>,
 438    /// The primary range of text to be highlighted in the excerpt.
 439    /// In a multi-buffer search, this would be the text that matched the search
 440    pub primary: Range<T>,
 441}
 442
 443impl<T: Clone> ExcerptRange<T> {
 444    pub fn new(context: Range<T>) -> Self {
 445        Self {
 446            context: context.clone(),
 447            primary: context,
 448        }
 449    }
 450}
 451
 452#[derive(Clone, Debug, Default)]
 453pub struct ExcerptSummary {
 454    excerpt_id: ExcerptId,
 455    /// The location of the last [`Excerpt`] being summarized
 456    excerpt_locator: Locator,
 457    widest_line_number: u32,
 458    text: TextSummary,
 459}
 460
 461#[derive(Debug, Clone)]
 462pub struct DiffTransformSummary {
 463    input: TextSummary,
 464    output: TextSummary,
 465}
 466
 467#[derive(Clone)]
 468pub struct MultiBufferRows<'a> {
 469    point: Point,
 470    is_empty: bool,
 471    is_singleton: bool,
 472    cursor: MultiBufferCursor<'a, Point>,
 473}
 474
 475pub struct MultiBufferChunks<'a> {
 476    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 477    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 478    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 479    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 480    buffer_chunk: Option<Chunk<'a>>,
 481    range: Range<usize>,
 482    excerpt_offset_range: Range<ExcerptOffset>,
 483    excerpt_chunks: Option<ExcerptChunks<'a>>,
 484    language_aware: bool,
 485}
 486
 487pub struct ReversedMultiBufferChunks<'a> {
 488    cursor: MultiBufferCursor<'a, usize>,
 489    current_chunks: Option<rope::Chunks<'a>>,
 490    start: usize,
 491    offset: usize,
 492}
 493
 494pub struct MultiBufferBytes<'a> {
 495    range: Range<usize>,
 496    cursor: MultiBufferCursor<'a, usize>,
 497    excerpt_bytes: Option<text::Bytes<'a>>,
 498    has_trailing_newline: bool,
 499    chunk: &'a [u8],
 500}
 501
 502pub struct ReversedMultiBufferBytes<'a> {
 503    range: Range<usize>,
 504    chunks: ReversedMultiBufferChunks<'a>,
 505    chunk: &'a [u8],
 506}
 507
 508#[derive(Clone)]
 509struct DiffTransforms<D> {
 510    output_dimension: OutputDimension<D>,
 511    excerpt_dimension: ExcerptDimension<D>,
 512}
 513
 514impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 515    fn zero(cx: &<DiffTransformSummary as sum_tree::Summary>::Context) -> Self {
 516        Self {
 517            output_dimension: OutputDimension::zero(cx),
 518            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 519                cx,
 520            ),
 521        }
 522    }
 523
 524    fn add_summary(
 525        &mut self,
 526        summary: &'a DiffTransformSummary,
 527        cx: &<DiffTransformSummary as sum_tree::Summary>::Context,
 528    ) {
 529        self.output_dimension.add_summary(summary, cx);
 530        self.excerpt_dimension.add_summary(summary, cx);
 531    }
 532}
 533
 534#[derive(Clone)]
 535struct MultiBufferCursor<'a, D: TextDimension> {
 536    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 537    diff_transforms: Cursor<'a, DiffTransform, DiffTransforms<D>>,
 538    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 539    cached_region: Option<MultiBufferRegion<'a, D>>,
 540}
 541
 542#[derive(Clone)]
 543struct MultiBufferRegion<'a, D: TextDimension> {
 544    buffer: &'a BufferSnapshot,
 545    is_main_buffer: bool,
 546    diff_hunk_status: Option<DiffHunkStatus>,
 547    excerpt: &'a Excerpt,
 548    buffer_range: Range<D>,
 549    range: Range<D>,
 550    has_trailing_newline: bool,
 551}
 552
 553struct ExcerptChunks<'a> {
 554    excerpt_id: ExcerptId,
 555    content_chunks: BufferChunks<'a>,
 556    footer_height: usize,
 557}
 558
 559#[derive(Debug)]
 560struct BufferEdit {
 561    range: Range<usize>,
 562    new_text: Arc<str>,
 563    is_insertion: bool,
 564    original_indent_column: Option<u32>,
 565    excerpt_id: ExcerptId,
 566}
 567
 568#[derive(Clone, Copy, Debug, PartialEq)]
 569enum DiffChangeKind {
 570    BufferEdited,
 571    DiffUpdated { base_changed: bool },
 572    ExpandOrCollapseHunks { expand: bool },
 573}
 574
 575#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 576pub enum ExpandExcerptDirection {
 577    Up,
 578    Down,
 579    UpAndDown,
 580}
 581
 582impl ExpandExcerptDirection {
 583    pub fn should_expand_up(&self) -> bool {
 584        match self {
 585            ExpandExcerptDirection::Up => true,
 586            ExpandExcerptDirection::Down => false,
 587            ExpandExcerptDirection::UpAndDown => true,
 588        }
 589    }
 590
 591    pub fn should_expand_down(&self) -> bool {
 592        match self {
 593            ExpandExcerptDirection::Up => false,
 594            ExpandExcerptDirection::Down => true,
 595            ExpandExcerptDirection::UpAndDown => true,
 596        }
 597    }
 598}
 599
 600#[derive(Clone, Debug, PartialEq)]
 601pub struct IndentGuide {
 602    pub buffer_id: BufferId,
 603    pub start_row: MultiBufferRow,
 604    pub end_row: MultiBufferRow,
 605    pub depth: u32,
 606    pub tab_size: u32,
 607    pub settings: IndentGuideSettings,
 608}
 609
 610impl IndentGuide {
 611    pub fn indent_level(&self) -> u32 {
 612        self.depth * self.tab_size
 613    }
 614}
 615
 616impl MultiBuffer {
 617    pub fn new(capability: Capability) -> Self {
 618        Self {
 619            snapshot: RefCell::new(MultiBufferSnapshot {
 620                show_headers: true,
 621                ..MultiBufferSnapshot::default()
 622            }),
 623            buffers: RefCell::default(),
 624            diffs: HashMap::default(),
 625            subscriptions: Topic::default(),
 626            singleton: false,
 627            capability,
 628            title: None,
 629            excerpts_by_path: Default::default(),
 630            paths_by_excerpt: Default::default(),
 631            buffer_changed_since_sync: Default::default(),
 632            history: History {
 633                next_transaction_id: clock::Lamport::default(),
 634                undo_stack: Vec::new(),
 635                redo_stack: Vec::new(),
 636                transaction_depth: 0,
 637                group_interval: Duration::from_millis(300),
 638            },
 639        }
 640    }
 641
 642    pub fn without_headers(capability: Capability) -> Self {
 643        Self {
 644            snapshot: Default::default(),
 645            buffers: Default::default(),
 646            excerpts_by_path: Default::default(),
 647            paths_by_excerpt: Default::default(),
 648            diffs: HashMap::default(),
 649            subscriptions: Default::default(),
 650            singleton: false,
 651            capability,
 652            buffer_changed_since_sync: Default::default(),
 653            history: History {
 654                next_transaction_id: Default::default(),
 655                undo_stack: Default::default(),
 656                redo_stack: Default::default(),
 657                transaction_depth: 0,
 658                group_interval: Duration::from_millis(300),
 659            },
 660            title: Default::default(),
 661        }
 662    }
 663
 664    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 665        let mut buffers = HashMap::default();
 666        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 667        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 668            buffer_state.buffer.update(new_cx, |buffer, _| {
 669                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 670            });
 671            buffers.insert(
 672                *buffer_id,
 673                BufferState {
 674                    buffer: buffer_state.buffer.clone(),
 675                    last_version: buffer_state.last_version.clone(),
 676                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 677                    excerpts: buffer_state.excerpts.clone(),
 678                    _subscriptions: [
 679                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 680                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 681                    ],
 682                },
 683            );
 684        }
 685        let mut diff_bases = HashMap::default();
 686        for (buffer_id, diff) in self.diffs.iter() {
 687            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 688        }
 689        Self {
 690            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 691            buffers: RefCell::new(buffers),
 692            excerpts_by_path: Default::default(),
 693            paths_by_excerpt: Default::default(),
 694            diffs: diff_bases,
 695            subscriptions: Default::default(),
 696            singleton: self.singleton,
 697            capability: self.capability,
 698            history: self.history.clone(),
 699            title: self.title.clone(),
 700            buffer_changed_since_sync,
 701        }
 702    }
 703
 704    pub fn with_title(mut self, title: String) -> Self {
 705        self.title = Some(title);
 706        self
 707    }
 708
 709    pub fn read_only(&self) -> bool {
 710        self.capability == Capability::ReadOnly
 711    }
 712
 713    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 714        let mut this = Self::new(buffer.read(cx).capability());
 715        this.singleton = true;
 716        this.push_excerpts(
 717            buffer,
 718            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 719            cx,
 720        );
 721        this.snapshot.borrow_mut().singleton = true;
 722        this
 723    }
 724
 725    /// Returns an up-to-date snapshot of the MultiBuffer.
 726    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 727        self.sync(cx);
 728        self.snapshot.borrow().clone()
 729    }
 730
 731    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 732        self.sync(cx);
 733        self.snapshot.borrow()
 734    }
 735
 736    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 737        if self.singleton {
 738            return Some(
 739                self.buffers
 740                    .borrow()
 741                    .values()
 742                    .next()
 743                    .unwrap()
 744                    .buffer
 745                    .clone(),
 746            );
 747        } else {
 748            None
 749        }
 750    }
 751
 752    pub fn is_singleton(&self) -> bool {
 753        self.singleton
 754    }
 755
 756    pub fn subscribe(&mut self) -> Subscription {
 757        self.subscriptions.subscribe()
 758    }
 759
 760    pub fn is_dirty(&self, cx: &App) -> bool {
 761        self.read(cx).is_dirty()
 762    }
 763
 764    pub fn has_deleted_file(&self, cx: &App) -> bool {
 765        self.read(cx).has_deleted_file()
 766    }
 767
 768    pub fn has_conflict(&self, cx: &App) -> bool {
 769        self.read(cx).has_conflict()
 770    }
 771
 772    // The `is_empty` signature doesn't match what clippy expects
 773    #[allow(clippy::len_without_is_empty)]
 774    pub fn len(&self, cx: &App) -> usize {
 775        self.read(cx).len()
 776    }
 777
 778    pub fn is_empty(&self) -> bool {
 779        self.buffers.borrow().is_empty()
 780    }
 781
 782    pub fn symbols_containing<T: ToOffset>(
 783        &self,
 784        offset: T,
 785        theme: Option<&SyntaxTheme>,
 786        cx: &App,
 787    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 788        self.read(cx).symbols_containing(offset, theme)
 789    }
 790
 791    pub fn edit<I, S, T>(
 792        &self,
 793        edits: I,
 794        autoindent_mode: Option<AutoindentMode>,
 795        cx: &mut Context<Self>,
 796    ) where
 797        I: IntoIterator<Item = (Range<S>, T)>,
 798        S: ToOffset,
 799        T: Into<Arc<str>>,
 800    {
 801        let snapshot = self.read(cx);
 802        let edits = edits
 803            .into_iter()
 804            .map(|(range, new_text)| {
 805                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 806                if range.start > range.end {
 807                    mem::swap(&mut range.start, &mut range.end);
 808                }
 809                (range, new_text.into())
 810            })
 811            .collect::<Vec<_>>();
 812
 813        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 814
 815        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 816        fn edit_internal(
 817            this: &MultiBuffer,
 818            snapshot: Ref<MultiBufferSnapshot>,
 819            edits: Vec<(Range<usize>, Arc<str>)>,
 820            mut autoindent_mode: Option<AutoindentMode>,
 821            cx: &mut Context<MultiBuffer>,
 822        ) {
 823            if this.read_only() || this.buffers.borrow().is_empty() {
 824                return;
 825            }
 826
 827            let original_indent_columns = match &mut autoindent_mode {
 828                Some(AutoindentMode::Block {
 829                    original_indent_columns,
 830                }) => mem::take(original_indent_columns),
 831                _ => Default::default(),
 832            };
 833
 834            let (buffer_edits, edited_excerpt_ids) =
 835                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 836            drop(snapshot);
 837
 838            let mut buffer_ids = Vec::new();
 839            for (buffer_id, mut edits) in buffer_edits {
 840                buffer_ids.push(buffer_id);
 841                edits.sort_by_key(|edit| edit.range.start);
 842                this.buffers.borrow()[&buffer_id]
 843                    .buffer
 844                    .update(cx, |buffer, cx| {
 845                        let mut edits = edits.into_iter().peekable();
 846                        let mut insertions = Vec::new();
 847                        let mut original_indent_columns = Vec::new();
 848                        let mut deletions = Vec::new();
 849                        let empty_str: Arc<str> = Arc::default();
 850                        while let Some(BufferEdit {
 851                            mut range,
 852                            mut new_text,
 853                            mut is_insertion,
 854                            original_indent_column,
 855                            excerpt_id,
 856                        }) = edits.next()
 857                        {
 858                            while let Some(BufferEdit {
 859                                range: next_range,
 860                                is_insertion: next_is_insertion,
 861                                new_text: next_new_text,
 862                                excerpt_id: next_excerpt_id,
 863                                ..
 864                            }) = edits.peek()
 865                            {
 866                                if range.end >= next_range.start {
 867                                    range.end = cmp::max(next_range.end, range.end);
 868                                    is_insertion |= *next_is_insertion;
 869                                    if excerpt_id == *next_excerpt_id {
 870                                        new_text = format!("{new_text}{next_new_text}").into();
 871                                    }
 872                                    edits.next();
 873                                } else {
 874                                    break;
 875                                }
 876                            }
 877
 878                            if is_insertion {
 879                                original_indent_columns.push(original_indent_column);
 880                                insertions.push((
 881                                    buffer.anchor_before(range.start)
 882                                        ..buffer.anchor_before(range.end),
 883                                    new_text.clone(),
 884                                ));
 885                            } else if !range.is_empty() {
 886                                deletions.push((
 887                                    buffer.anchor_before(range.start)
 888                                        ..buffer.anchor_before(range.end),
 889                                    empty_str.clone(),
 890                                ));
 891                            }
 892                        }
 893
 894                        let deletion_autoindent_mode =
 895                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 896                                Some(AutoindentMode::Block {
 897                                    original_indent_columns: Default::default(),
 898                                })
 899                            } else {
 900                                autoindent_mode.clone()
 901                            };
 902                        let insertion_autoindent_mode =
 903                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 904                                Some(AutoindentMode::Block {
 905                                    original_indent_columns,
 906                                })
 907                            } else {
 908                                autoindent_mode.clone()
 909                            };
 910
 911                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 912                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 913                    })
 914            }
 915
 916            cx.emit(Event::ExcerptsEdited {
 917                excerpt_ids: edited_excerpt_ids,
 918                buffer_ids,
 919            });
 920        }
 921    }
 922
 923    fn convert_edits_to_buffer_edits(
 924        &self,
 925        edits: Vec<(Range<usize>, Arc<str>)>,
 926        snapshot: &MultiBufferSnapshot,
 927        original_indent_columns: &[Option<u32>],
 928    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 929        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 930        let mut edited_excerpt_ids = Vec::new();
 931        let mut cursor = snapshot.cursor::<usize>();
 932        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 933            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 934
 935            cursor.seek(&range.start);
 936            let mut start_region = cursor.region().expect("start offset out of bounds");
 937            if !start_region.is_main_buffer {
 938                cursor.next();
 939                if let Some(region) = cursor.region() {
 940                    start_region = region;
 941                } else {
 942                    continue;
 943                }
 944            }
 945
 946            if range.end < start_region.range.start {
 947                continue;
 948            }
 949
 950            if range.end > start_region.range.end {
 951                cursor.seek_forward(&range.end);
 952            }
 953            let mut end_region = cursor.region().expect("end offset out of bounds");
 954            if !end_region.is_main_buffer {
 955                cursor.prev();
 956                if let Some(region) = cursor.region() {
 957                    end_region = region;
 958                } else {
 959                    continue;
 960                }
 961            }
 962
 963            if range.start > end_region.range.end {
 964                continue;
 965            }
 966
 967            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 968            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 969            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 970                .min(start_region.buffer_range.end);
 971            let buffer_end =
 972                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 973
 974            if start_region.excerpt.id == end_region.excerpt.id {
 975                if start_region.is_main_buffer {
 976                    edited_excerpt_ids.push(start_region.excerpt.id);
 977                    buffer_edits
 978                        .entry(start_region.buffer.remote_id())
 979                        .or_default()
 980                        .push(BufferEdit {
 981                            range: buffer_start..buffer_end,
 982                            new_text,
 983                            is_insertion: true,
 984                            original_indent_column,
 985                            excerpt_id: start_region.excerpt.id,
 986                        });
 987                }
 988            } else {
 989                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 990                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 991                if start_region.is_main_buffer {
 992                    edited_excerpt_ids.push(start_region.excerpt.id);
 993                    buffer_edits
 994                        .entry(start_region.buffer.remote_id())
 995                        .or_default()
 996                        .push(BufferEdit {
 997                            range: start_excerpt_range,
 998                            new_text: new_text.clone(),
 999                            is_insertion: true,
1000                            original_indent_column,
1001                            excerpt_id: start_region.excerpt.id,
1002                        });
1003                }
1004                if end_region.is_main_buffer {
1005                    edited_excerpt_ids.push(end_region.excerpt.id);
1006                    buffer_edits
1007                        .entry(end_region.buffer.remote_id())
1008                        .or_default()
1009                        .push(BufferEdit {
1010                            range: end_excerpt_range,
1011                            new_text: new_text.clone(),
1012                            is_insertion: false,
1013                            original_indent_column,
1014                            excerpt_id: end_region.excerpt.id,
1015                        });
1016                }
1017
1018                cursor.seek(&range.start);
1019                cursor.next_excerpt();
1020                while let Some(region) = cursor.region() {
1021                    if region.excerpt.id == end_region.excerpt.id {
1022                        break;
1023                    }
1024                    if region.is_main_buffer {
1025                        edited_excerpt_ids.push(region.excerpt.id);
1026                        buffer_edits
1027                            .entry(region.buffer.remote_id())
1028                            .or_default()
1029                            .push(BufferEdit {
1030                                range: region.buffer_range,
1031                                new_text: new_text.clone(),
1032                                is_insertion: false,
1033                                original_indent_column,
1034                                excerpt_id: region.excerpt.id,
1035                            });
1036                    }
1037                    cursor.next_excerpt();
1038                }
1039            }
1040        }
1041        (buffer_edits, edited_excerpt_ids)
1042    }
1043
1044    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1045    where
1046        I: IntoIterator<Item = Range<S>>,
1047        S: ToOffset,
1048    {
1049        let snapshot = self.read(cx);
1050        let empty = Arc::<str>::from("");
1051        let edits = ranges
1052            .into_iter()
1053            .map(|range| {
1054                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1055                if range.start > range.end {
1056                    mem::swap(&mut range.start, &mut range.end);
1057                }
1058                (range, empty.clone())
1059            })
1060            .collect::<Vec<_>>();
1061
1062        return autoindent_ranges_internal(self, snapshot, edits, cx);
1063
1064        fn autoindent_ranges_internal(
1065            this: &MultiBuffer,
1066            snapshot: Ref<MultiBufferSnapshot>,
1067            edits: Vec<(Range<usize>, Arc<str>)>,
1068            cx: &mut Context<MultiBuffer>,
1069        ) {
1070            if this.read_only() || this.buffers.borrow().is_empty() {
1071                return;
1072            }
1073
1074            let (buffer_edits, edited_excerpt_ids) =
1075                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1076            drop(snapshot);
1077
1078            let mut buffer_ids = Vec::new();
1079            for (buffer_id, mut edits) in buffer_edits {
1080                buffer_ids.push(buffer_id);
1081                edits.sort_unstable_by_key(|edit| edit.range.start);
1082
1083                let mut ranges: Vec<Range<usize>> = Vec::new();
1084                for edit in edits {
1085                    if let Some(last_range) = ranges.last_mut() {
1086                        if edit.range.start <= last_range.end {
1087                            last_range.end = last_range.end.max(edit.range.end);
1088                            continue;
1089                        }
1090                    }
1091                    ranges.push(edit.range);
1092                }
1093
1094                this.buffers.borrow()[&buffer_id]
1095                    .buffer
1096                    .update(cx, |buffer, cx| {
1097                        buffer.autoindent_ranges(ranges, cx);
1098                    })
1099            }
1100
1101            cx.emit(Event::ExcerptsEdited {
1102                excerpt_ids: edited_excerpt_ids,
1103                buffer_ids,
1104            });
1105        }
1106    }
1107
1108    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1109    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1110    // Panics if the given position is invalid.
1111    pub fn insert_empty_line(
1112        &mut self,
1113        position: impl ToPoint,
1114        space_above: bool,
1115        space_below: bool,
1116        cx: &mut Context<Self>,
1117    ) -> Point {
1118        let multibuffer_point = position.to_point(&self.read(cx));
1119        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1120        self.start_transaction(cx);
1121        let empty_line_start = buffer.update(cx, |buffer, cx| {
1122            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1123        });
1124        self.end_transaction(cx);
1125        multibuffer_point + (empty_line_start - buffer_point)
1126    }
1127
1128    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1129        self.start_transaction_at(Instant::now(), cx)
1130    }
1131
1132    pub fn start_transaction_at(
1133        &mut self,
1134        now: Instant,
1135        cx: &mut Context<Self>,
1136    ) -> Option<TransactionId> {
1137        if let Some(buffer) = self.as_singleton() {
1138            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1139        }
1140
1141        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1142            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1143        }
1144        self.history.start_transaction(now)
1145    }
1146
1147    pub fn last_transaction_id(&self, cx: &App) -> Option<TransactionId> {
1148        if let Some(buffer) = self.as_singleton() {
1149            return buffer
1150                .read(cx)
1151                .peek_undo_stack()
1152                .map(|history_entry| history_entry.transaction_id());
1153        } else {
1154            let last_transaction = self.history.undo_stack.last()?;
1155            return Some(last_transaction.id);
1156        }
1157    }
1158
1159    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1160        self.end_transaction_at(Instant::now(), cx)
1161    }
1162
1163    pub fn end_transaction_at(
1164        &mut self,
1165        now: Instant,
1166        cx: &mut Context<Self>,
1167    ) -> Option<TransactionId> {
1168        if let Some(buffer) = self.as_singleton() {
1169            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1170        }
1171
1172        let mut buffer_transactions = HashMap::default();
1173        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1174            if let Some(transaction_id) =
1175                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1176            {
1177                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1178            }
1179        }
1180
1181        if self.history.end_transaction(now, buffer_transactions) {
1182            let transaction_id = self.history.group().unwrap();
1183            Some(transaction_id)
1184        } else {
1185            None
1186        }
1187    }
1188
1189    pub fn edited_ranges_for_transaction<D>(
1190        &self,
1191        transaction_id: TransactionId,
1192        cx: &App,
1193    ) -> Vec<Range<D>>
1194    where
1195        D: TextDimension + Ord + Sub<D, Output = D>,
1196    {
1197        let Some(transaction) = self.history.transaction(transaction_id) else {
1198            return Vec::new();
1199        };
1200
1201        let mut ranges = Vec::new();
1202        let snapshot = self.read(cx);
1203        let buffers = self.buffers.borrow();
1204        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1205
1206        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1207            let Some(buffer_state) = buffers.get(buffer_id) else {
1208                continue;
1209            };
1210
1211            let buffer = buffer_state.buffer.read(cx);
1212            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1213                for excerpt_id in &buffer_state.excerpts {
1214                    cursor.seek(excerpt_id, Bias::Left, &());
1215                    if let Some(excerpt) = cursor.item() {
1216                        if excerpt.locator == *excerpt_id {
1217                            let excerpt_buffer_start =
1218                                excerpt.range.context.start.summary::<D>(&buffer);
1219                            let excerpt_buffer_end =
1220                                excerpt.range.context.end.summary::<D>(&buffer);
1221                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1222                            if excerpt_range.contains(&range.start)
1223                                && excerpt_range.contains(&range.end)
1224                            {
1225                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1226
1227                                let mut start = excerpt_start;
1228                                start.add_assign(&(range.start - excerpt_buffer_start));
1229                                let mut end = excerpt_start;
1230                                end.add_assign(&(range.end - excerpt_buffer_start));
1231
1232                                ranges.push(start..end);
1233                                break;
1234                            }
1235                        }
1236                    }
1237                }
1238            }
1239        }
1240
1241        ranges.sort_by_key(|range| range.start);
1242        ranges
1243    }
1244
1245    pub fn merge_transactions(
1246        &mut self,
1247        transaction: TransactionId,
1248        destination: TransactionId,
1249        cx: &mut Context<Self>,
1250    ) {
1251        if let Some(buffer) = self.as_singleton() {
1252            buffer.update(cx, |buffer, _| {
1253                buffer.merge_transactions(transaction, destination)
1254            });
1255        } else if let Some(transaction) = self.history.forget(transaction) {
1256            if let Some(destination) = self.history.transaction_mut(destination) {
1257                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1258                    if let Some(destination_buffer_transaction_id) =
1259                        destination.buffer_transactions.get(&buffer_id)
1260                    {
1261                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1262                            state.buffer.update(cx, |buffer, _| {
1263                                buffer.merge_transactions(
1264                                    buffer_transaction_id,
1265                                    *destination_buffer_transaction_id,
1266                                )
1267                            });
1268                        }
1269                    } else {
1270                        destination
1271                            .buffer_transactions
1272                            .insert(buffer_id, buffer_transaction_id);
1273                    }
1274                }
1275            }
1276        }
1277    }
1278
1279    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1280        self.history.finalize_last_transaction();
1281        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1282            buffer.update(cx, |buffer, _| {
1283                buffer.finalize_last_transaction();
1284            });
1285        }
1286    }
1287
1288    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1289    where
1290        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1291    {
1292        self.history
1293            .push_transaction(buffer_transactions, Instant::now(), cx);
1294        self.history.finalize_last_transaction();
1295    }
1296
1297    pub fn group_until_transaction(
1298        &mut self,
1299        transaction_id: TransactionId,
1300        cx: &mut Context<Self>,
1301    ) {
1302        if let Some(buffer) = self.as_singleton() {
1303            buffer.update(cx, |buffer, _| {
1304                buffer.group_until_transaction(transaction_id)
1305            });
1306        } else {
1307            self.history.group_until(transaction_id);
1308        }
1309    }
1310
1311    pub fn set_active_selections(
1312        &self,
1313        selections: &[Selection<Anchor>],
1314        line_mode: bool,
1315        cursor_shape: CursorShape,
1316        cx: &mut Context<Self>,
1317    ) {
1318        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1319            Default::default();
1320        let snapshot = self.read(cx);
1321        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1322        for selection in selections {
1323            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1324            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1325
1326            cursor.seek(&Some(start_locator), Bias::Left, &());
1327            while let Some(excerpt) = cursor.item() {
1328                if excerpt.locator > *end_locator {
1329                    break;
1330                }
1331
1332                let mut start = excerpt.range.context.start;
1333                let mut end = excerpt.range.context.end;
1334                if excerpt.id == selection.start.excerpt_id {
1335                    start = selection.start.text_anchor;
1336                }
1337                if excerpt.id == selection.end.excerpt_id {
1338                    end = selection.end.text_anchor;
1339                }
1340                selections_by_buffer
1341                    .entry(excerpt.buffer_id)
1342                    .or_default()
1343                    .push(Selection {
1344                        id: selection.id,
1345                        start,
1346                        end,
1347                        reversed: selection.reversed,
1348                        goal: selection.goal,
1349                    });
1350
1351                cursor.next(&());
1352            }
1353        }
1354
1355        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1356            if !selections_by_buffer.contains_key(buffer_id) {
1357                buffer_state
1358                    .buffer
1359                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1360            }
1361        }
1362
1363        for (buffer_id, mut selections) in selections_by_buffer {
1364            self.buffers.borrow()[&buffer_id]
1365                .buffer
1366                .update(cx, |buffer, cx| {
1367                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1368                    let mut selections = selections.into_iter().peekable();
1369                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1370                        let mut selection = selections.next()?;
1371                        while let Some(next_selection) = selections.peek() {
1372                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1373                                let next_selection = selections.next().unwrap();
1374                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1375                                    selection.end = next_selection.end;
1376                                }
1377                            } else {
1378                                break;
1379                            }
1380                        }
1381                        Some(selection)
1382                    }));
1383                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1384                });
1385        }
1386    }
1387
1388    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1389        for buffer in self.buffers.borrow().values() {
1390            buffer
1391                .buffer
1392                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1393        }
1394    }
1395
1396    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1397        let mut transaction_id = None;
1398        if let Some(buffer) = self.as_singleton() {
1399            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1400        } else {
1401            while let Some(transaction) = self.history.pop_undo() {
1402                let mut undone = false;
1403                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1404                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1405                        undone |= buffer.update(cx, |buffer, cx| {
1406                            let undo_to = *buffer_transaction_id;
1407                            if let Some(entry) = buffer.peek_undo_stack() {
1408                                *buffer_transaction_id = entry.transaction_id();
1409                            }
1410                            buffer.undo_to_transaction(undo_to, cx)
1411                        });
1412                    }
1413                }
1414
1415                if undone {
1416                    transaction_id = Some(transaction.id);
1417                    break;
1418                }
1419            }
1420        }
1421
1422        if let Some(transaction_id) = transaction_id {
1423            cx.emit(Event::TransactionUndone { transaction_id });
1424        }
1425
1426        transaction_id
1427    }
1428
1429    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1430        if let Some(buffer) = self.as_singleton() {
1431            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1432        }
1433
1434        while let Some(transaction) = self.history.pop_redo() {
1435            let mut redone = false;
1436            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1437                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1438                    redone |= buffer.update(cx, |buffer, cx| {
1439                        let redo_to = *buffer_transaction_id;
1440                        if let Some(entry) = buffer.peek_redo_stack() {
1441                            *buffer_transaction_id = entry.transaction_id();
1442                        }
1443                        buffer.redo_to_transaction(redo_to, cx)
1444                    });
1445                }
1446            }
1447
1448            if redone {
1449                return Some(transaction.id);
1450            }
1451        }
1452
1453        None
1454    }
1455
1456    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1457        if let Some(buffer) = self.as_singleton() {
1458            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1459        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1460            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1461                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1462                    buffer.update(cx, |buffer, cx| {
1463                        buffer.undo_transaction(*transaction_id, cx)
1464                    });
1465                }
1466            }
1467        }
1468    }
1469
1470    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1471        if let Some(buffer) = self.as_singleton() {
1472            buffer.update(cx, |buffer, _| {
1473                buffer.forget_transaction(transaction_id);
1474            });
1475        } else if let Some(transaction) = self.history.forget(transaction_id) {
1476            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1477                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1478                    state.buffer.update(cx, |buffer, _| {
1479                        buffer.forget_transaction(buffer_transaction_id);
1480                    });
1481                }
1482            }
1483        }
1484    }
1485
1486    pub fn push_excerpts<O>(
1487        &mut self,
1488        buffer: Entity<Buffer>,
1489        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1490        cx: &mut Context<Self>,
1491    ) -> Vec<ExcerptId>
1492    where
1493        O: text::ToOffset,
1494    {
1495        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1496    }
1497
1498    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1499        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1500        let snapshot = self.snapshot(cx);
1501        let excerpt = snapshot.excerpt(*excerpt_id)?;
1502        Some(Anchor::in_buffer(
1503            *excerpt_id,
1504            excerpt.buffer_id,
1505            excerpt.range.context.start,
1506        ))
1507    }
1508
1509    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1510        self.excerpts_by_path.keys()
1511    }
1512
1513    fn expand_excerpts_with_paths(
1514        &mut self,
1515        ids: impl IntoIterator<Item = ExcerptId>,
1516        line_count: u32,
1517        direction: ExpandExcerptDirection,
1518        cx: &mut Context<Self>,
1519    ) {
1520        let grouped = ids
1521            .into_iter()
1522            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1523            .into_iter()
1524            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1525            .collect::<Vec<_>>();
1526        let snapshot = self.snapshot(cx);
1527
1528        for (path, ids) in grouped.into_iter() {
1529            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1530                continue;
1531            };
1532
1533            let ids_to_expand = HashSet::from_iter(ids);
1534            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1535                let excerpt = snapshot.excerpt(*excerpt_id)?;
1536
1537                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1538                if ids_to_expand.contains(excerpt_id) {
1539                    match direction {
1540                        ExpandExcerptDirection::Up => {
1541                            context.start.row = context.start.row.saturating_sub(line_count);
1542                            context.start.column = 0;
1543                        }
1544                        ExpandExcerptDirection::Down => {
1545                            context.end.row =
1546                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1547                            context.end.column = excerpt.buffer.line_len(context.end.row);
1548                        }
1549                        ExpandExcerptDirection::UpAndDown => {
1550                            context.start.row = context.start.row.saturating_sub(line_count);
1551                            context.start.column = 0;
1552                            context.end.row =
1553                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1554                            context.end.column = excerpt.buffer.line_len(context.end.row);
1555                        }
1556                    }
1557                }
1558
1559                Some(ExcerptRange {
1560                    context,
1561                    primary: excerpt.range.primary.to_point(&excerpt.buffer),
1562                })
1563            });
1564            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1565            for range in expanded_ranges {
1566                if let Some(last_range) = merged_ranges.last_mut() {
1567                    if last_range.context.end >= range.context.start {
1568                        last_range.context.end = range.context.end;
1569                        continue;
1570                    }
1571                }
1572                merged_ranges.push(range)
1573            }
1574            let Some(excerpt_id) = excerpt_ids.first() else {
1575                continue;
1576            };
1577            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1578                continue;
1579            };
1580
1581            let Some(buffer) = self
1582                .buffers
1583                .borrow()
1584                .get(buffer_id)
1585                .map(|b| b.buffer.clone())
1586            else {
1587                continue;
1588            };
1589
1590            let buffer_snapshot = buffer.read(cx).snapshot();
1591            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1592        }
1593    }
1594
1595    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1596    pub fn set_excerpts_for_path(
1597        &mut self,
1598        path: PathKey,
1599        buffer: Entity<Buffer>,
1600        ranges: impl IntoIterator<Item = Range<Point>>,
1601        context_line_count: u32,
1602        cx: &mut Context<Self>,
1603    ) -> (Vec<Range<Anchor>>, bool) {
1604        let buffer_snapshot = buffer.read(cx).snapshot();
1605        let excerpt_ranges = build_excerpt_ranges(ranges, context_line_count, &buffer_snapshot);
1606
1607        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1608        self.set_merged_excerpt_ranges_for_path(
1609            path,
1610            buffer,
1611            excerpt_ranges,
1612            &buffer_snapshot,
1613            new,
1614            counts,
1615            cx,
1616        )
1617    }
1618
1619    pub fn set_excerpt_ranges_for_path(
1620        &mut self,
1621        path: PathKey,
1622        buffer: Entity<Buffer>,
1623        buffer_snapshot: &BufferSnapshot,
1624        excerpt_ranges: Vec<ExcerptRange<Point>>,
1625        cx: &mut Context<Self>,
1626    ) -> (Vec<Range<Anchor>>, bool) {
1627        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1628        self.set_merged_excerpt_ranges_for_path(
1629            path,
1630            buffer,
1631            excerpt_ranges,
1632            buffer_snapshot,
1633            new,
1634            counts,
1635            cx,
1636        )
1637    }
1638
1639    pub fn set_anchored_excerpts_for_path(
1640        &self,
1641        buffer: Entity<Buffer>,
1642        ranges: Vec<Range<text::Anchor>>,
1643        context_line_count: u32,
1644        cx: &mut Context<Self>,
1645    ) -> Task<Vec<Range<Anchor>>> {
1646        let buffer_snapshot = buffer.read(cx).snapshot();
1647        let path_key = PathKey::for_buffer(&buffer, cx);
1648        cx.spawn(async move |multi_buffer, cx| {
1649            let snapshot = buffer_snapshot.clone();
1650            let (excerpt_ranges, new, counts) = cx
1651                .background_spawn(async move {
1652                    let ranges = ranges.into_iter().map(|range| range.to_point(&snapshot));
1653                    let excerpt_ranges =
1654                        build_excerpt_ranges(ranges, context_line_count, &snapshot);
1655                    let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1656                    (excerpt_ranges, new, counts)
1657                })
1658                .await;
1659
1660            multi_buffer
1661                .update(cx, move |multi_buffer, cx| {
1662                    let (ranges, _) = multi_buffer.set_merged_excerpt_ranges_for_path(
1663                        path_key,
1664                        buffer,
1665                        excerpt_ranges,
1666                        &buffer_snapshot,
1667                        new,
1668                        counts,
1669                        cx,
1670                    );
1671                    ranges
1672                })
1673                .ok()
1674                .unwrap_or_default()
1675        })
1676    }
1677
1678    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1679    fn set_merged_excerpt_ranges_for_path(
1680        &mut self,
1681        path: PathKey,
1682        buffer: Entity<Buffer>,
1683        ranges: Vec<ExcerptRange<Point>>,
1684        buffer_snapshot: &BufferSnapshot,
1685        new: Vec<ExcerptRange<Point>>,
1686        counts: Vec<usize>,
1687        cx: &mut Context<Self>,
1688    ) -> (Vec<Range<Anchor>>, bool) {
1689        let (excerpt_ids, added_a_new_excerpt) =
1690            self.update_path_excerpts(path, buffer, &buffer_snapshot, new, cx);
1691
1692        let mut result = Vec::new();
1693        let mut ranges = ranges.into_iter();
1694        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(counts.into_iter()) {
1695            for range in ranges.by_ref().take(range_count) {
1696                let range = Anchor::range_in_buffer(
1697                    excerpt_id,
1698                    buffer_snapshot.remote_id(),
1699                    buffer_snapshot.anchor_before(&range.primary.start)
1700                        ..buffer_snapshot.anchor_after(&range.primary.end),
1701                );
1702                result.push(range)
1703            }
1704        }
1705        (result, added_a_new_excerpt)
1706    }
1707
1708    fn merge_excerpt_ranges<'a>(
1709        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1710    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1711        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1712        let mut counts: Vec<usize> = Vec::new();
1713        for range in expanded_ranges {
1714            if let Some(last_range) = merged_ranges.last_mut() {
1715                debug_assert!(
1716                    last_range.context.start <= range.context.start,
1717                    "Last range: {last_range:?} Range: {range:?}"
1718                );
1719                if last_range.context.end >= range.context.start
1720                    || last_range.context.end.row + 1 == range.context.start.row
1721                {
1722                    last_range.context.end = range.context.end.max(last_range.context.end);
1723                    *counts.last_mut().unwrap() += 1;
1724                    continue;
1725                }
1726            }
1727            merged_ranges.push(range.clone());
1728            counts.push(1);
1729        }
1730        return (merged_ranges, counts);
1731    }
1732
1733    fn update_path_excerpts(
1734        &mut self,
1735        path: PathKey,
1736        buffer: Entity<Buffer>,
1737        buffer_snapshot: &BufferSnapshot,
1738        new: Vec<ExcerptRange<Point>>,
1739        cx: &mut Context<Self>,
1740    ) -> (Vec<ExcerptId>, bool) {
1741        let mut insert_after = self
1742            .excerpts_by_path
1743            .range(..path.clone())
1744            .next_back()
1745            .map(|(_, value)| *value.last().unwrap())
1746            .unwrap_or(ExcerptId::min());
1747
1748        let existing = self
1749            .excerpts_by_path
1750            .get(&path)
1751            .cloned()
1752            .unwrap_or_default();
1753
1754        let mut new_iter = new.into_iter().peekable();
1755        let mut existing_iter = existing.into_iter().peekable();
1756
1757        let mut excerpt_ids = Vec::new();
1758        let mut to_remove = Vec::new();
1759        let mut to_insert: Vec<(ExcerptId, ExcerptRange<Point>)> = Vec::new();
1760        let mut added_a_new_excerpt = false;
1761        let snapshot = self.snapshot(cx);
1762
1763        let mut next_excerpt_id =
1764            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1765                last_entry.id.0 + 1
1766            } else {
1767                1
1768            };
1769
1770        let mut next_excerpt_id = move || ExcerptId(post_inc(&mut next_excerpt_id));
1771
1772        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1773        excerpts_cursor.next(&());
1774
1775        loop {
1776            let new = new_iter.peek();
1777            let existing = if let Some(existing_id) = existing_iter.peek() {
1778                let locator = snapshot.excerpt_locator_for_id(*existing_id);
1779                excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1780                if let Some(excerpt) = excerpts_cursor.item() {
1781                    if excerpt.buffer_id != buffer_snapshot.remote_id() {
1782                        to_remove.push(*existing_id);
1783                        existing_iter.next();
1784                        continue;
1785                    }
1786                    Some((
1787                        *existing_id,
1788                        excerpt.range.context.to_point(&buffer_snapshot),
1789                    ))
1790                } else {
1791                    None
1792                }
1793            } else {
1794                None
1795            };
1796
1797            if let Some((last_id, last)) = to_insert.last_mut() {
1798                if let Some(new) = new {
1799                    if last.context.end >= new.context.start {
1800                        last.context.end = last.context.end.max(new.context.end);
1801                        excerpt_ids.push(*last_id);
1802                        new_iter.next();
1803                        continue;
1804                    }
1805                }
1806                if let Some((existing_id, existing_range)) = &existing {
1807                    if last.context.end >= existing_range.start {
1808                        last.context.end = last.context.end.max(existing_range.end);
1809                        to_remove.push(*existing_id);
1810                        self.snapshot
1811                            .borrow_mut()
1812                            .replaced_excerpts
1813                            .insert(*existing_id, *last_id);
1814                        existing_iter.next();
1815                        continue;
1816                    }
1817                }
1818            }
1819
1820            match (new, existing) {
1821                (None, None) => break,
1822                (None, Some((existing_id, _))) => {
1823                    existing_iter.next();
1824                    to_remove.push(existing_id);
1825                    continue;
1826                }
1827                (Some(_), None) => {
1828                    added_a_new_excerpt = true;
1829                    let new_id = next_excerpt_id();
1830                    excerpt_ids.push(new_id);
1831                    to_insert.push((new_id, new_iter.next().unwrap()));
1832                    continue;
1833                }
1834                (Some(new), Some((_, existing_range))) => {
1835                    if existing_range.end < new.context.start {
1836                        let existing_id = existing_iter.next().unwrap();
1837                        to_remove.push(existing_id);
1838                        continue;
1839                    } else if existing_range.start > new.context.end {
1840                        let new_id = next_excerpt_id();
1841                        excerpt_ids.push(new_id);
1842                        to_insert.push((new_id, new_iter.next().unwrap()));
1843                        continue;
1844                    }
1845
1846                    if existing_range.start == new.context.start
1847                        && existing_range.end == new.context.end
1848                    {
1849                        self.insert_excerpts_with_ids_after(
1850                            insert_after,
1851                            buffer.clone(),
1852                            mem::take(&mut to_insert),
1853                            cx,
1854                        );
1855                        insert_after = existing_iter.next().unwrap();
1856                        excerpt_ids.push(insert_after);
1857                        new_iter.next();
1858                    } else {
1859                        let existing_id = existing_iter.next().unwrap();
1860                        let new_id = next_excerpt_id();
1861                        self.snapshot
1862                            .borrow_mut()
1863                            .replaced_excerpts
1864                            .insert(existing_id, new_id);
1865                        to_remove.push(existing_id);
1866                        let mut range = new_iter.next().unwrap();
1867                        range.context.start = range.context.start.min(existing_range.start);
1868                        range.context.end = range.context.end.max(existing_range.end);
1869                        excerpt_ids.push(new_id);
1870                        to_insert.push((new_id, range));
1871                    }
1872                }
1873            };
1874        }
1875
1876        self.insert_excerpts_with_ids_after(insert_after, buffer, to_insert, cx);
1877        self.remove_excerpts(to_remove, cx);
1878        if excerpt_ids.is_empty() {
1879            self.excerpts_by_path.remove(&path);
1880        } else {
1881            for excerpt_id in &excerpt_ids {
1882                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1883            }
1884            self.excerpts_by_path
1885                .insert(path, excerpt_ids.iter().dedup().cloned().collect());
1886        }
1887
1888        (excerpt_ids, added_a_new_excerpt)
1889    }
1890
1891    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1892        self.excerpts_by_path.keys().cloned()
1893    }
1894
1895    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1896        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1897            self.remove_excerpts(to_remove, cx)
1898        }
1899    }
1900
1901    pub fn insert_excerpts_after<O>(
1902        &mut self,
1903        prev_excerpt_id: ExcerptId,
1904        buffer: Entity<Buffer>,
1905        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1906        cx: &mut Context<Self>,
1907    ) -> Vec<ExcerptId>
1908    where
1909        O: text::ToOffset,
1910    {
1911        let mut ids = Vec::new();
1912        let mut next_excerpt_id =
1913            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1914                last_entry.id.0 + 1
1915            } else {
1916                1
1917            };
1918        self.insert_excerpts_with_ids_after(
1919            prev_excerpt_id,
1920            buffer,
1921            ranges.into_iter().map(|range| {
1922                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1923                ids.push(id);
1924                (id, range)
1925            }),
1926            cx,
1927        );
1928        ids
1929    }
1930
1931    pub fn insert_excerpts_with_ids_after<O>(
1932        &mut self,
1933        prev_excerpt_id: ExcerptId,
1934        buffer: Entity<Buffer>,
1935        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1936        cx: &mut Context<Self>,
1937    ) where
1938        O: text::ToOffset,
1939    {
1940        assert_eq!(self.history.transaction_depth, 0);
1941        let mut ranges = ranges.into_iter().peekable();
1942        if ranges.peek().is_none() {
1943            return Default::default();
1944        }
1945
1946        self.sync(cx);
1947
1948        let buffer_snapshot = buffer.read(cx).snapshot();
1949        let buffer_id = buffer_snapshot.remote_id();
1950
1951        let mut buffers = self.buffers.borrow_mut();
1952        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1953            self.buffer_changed_since_sync.replace(true);
1954            buffer.update(cx, |buffer, _| {
1955                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1956            });
1957            BufferState {
1958                last_version: buffer_snapshot.version().clone(),
1959                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1960                excerpts: Default::default(),
1961                _subscriptions: [
1962                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1963                    cx.subscribe(&buffer, Self::on_buffer_event),
1964                ],
1965                buffer: buffer.clone(),
1966            }
1967        });
1968
1969        let mut snapshot = self.snapshot.borrow_mut();
1970
1971        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1972        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1973        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1974        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1975        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1976
1977        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1978        new_excerpts.update_last(
1979            |excerpt| {
1980                excerpt.has_trailing_newline = true;
1981            },
1982            &(),
1983        );
1984
1985        let next_locator = if let Some(excerpt) = cursor.item() {
1986            excerpt.locator.clone()
1987        } else {
1988            Locator::max()
1989        };
1990
1991        let mut excerpts = Vec::new();
1992        while let Some((id, range)) = ranges.next() {
1993            let locator = Locator::between(&prev_locator, &next_locator);
1994            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1995                buffer_state.excerpts.insert(ix, locator.clone());
1996            }
1997            let range = ExcerptRange {
1998                context: buffer_snapshot.anchor_before(&range.context.start)
1999                    ..buffer_snapshot.anchor_after(&range.context.end),
2000                primary: buffer_snapshot.anchor_before(&range.primary.start)
2001                    ..buffer_snapshot.anchor_after(&range.primary.end),
2002            };
2003            excerpts.push((id, range.clone()));
2004            let excerpt = Excerpt::new(
2005                id,
2006                locator.clone(),
2007                buffer_id,
2008                buffer_snapshot.clone(),
2009                range,
2010                ranges.peek().is_some() || cursor.item().is_some(),
2011            );
2012            new_excerpts.push(excerpt, &());
2013            prev_locator = locator.clone();
2014
2015            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
2016                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
2017            }
2018            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
2019        }
2020
2021        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
2022
2023        let suffix = cursor.suffix(&());
2024        let changed_trailing_excerpt = suffix.is_empty();
2025        new_excerpts.append(suffix, &());
2026        drop(cursor);
2027        snapshot.excerpts = new_excerpts;
2028        snapshot.excerpt_ids = new_excerpt_ids;
2029        if changed_trailing_excerpt {
2030            snapshot.trailing_excerpt_update_count += 1;
2031        }
2032
2033        self.sync_diff_transforms(
2034            &mut snapshot,
2035            vec![Edit {
2036                old: edit_start..edit_start,
2037                new: edit_start..edit_end,
2038            }],
2039            DiffChangeKind::BufferEdited,
2040        );
2041        cx.emit(Event::Edited {
2042            singleton_buffer_edited: false,
2043            edited_buffer: None,
2044        });
2045        cx.emit(Event::ExcerptsAdded {
2046            buffer,
2047            predecessor: prev_excerpt_id,
2048            excerpts,
2049        });
2050        cx.notify();
2051    }
2052
2053    pub fn clear(&mut self, cx: &mut Context<Self>) {
2054        self.sync(cx);
2055        let ids = self.excerpt_ids();
2056        let removed_buffer_ids = self
2057            .buffers
2058            .borrow_mut()
2059            .drain()
2060            .map(|(id, _)| id)
2061            .collect();
2062        self.excerpts_by_path.clear();
2063        self.paths_by_excerpt.clear();
2064        let mut snapshot = self.snapshot.borrow_mut();
2065        let start = ExcerptOffset::new(0);
2066        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2067        snapshot.excerpts = Default::default();
2068        snapshot.trailing_excerpt_update_count += 1;
2069        snapshot.is_dirty = false;
2070        snapshot.has_deleted_file = false;
2071        snapshot.has_conflict = false;
2072        snapshot.replaced_excerpts.clear();
2073
2074        self.sync_diff_transforms(
2075            &mut snapshot,
2076            vec![Edit {
2077                old: start..prev_len,
2078                new: start..start,
2079            }],
2080            DiffChangeKind::BufferEdited,
2081        );
2082        cx.emit(Event::Edited {
2083            singleton_buffer_edited: false,
2084            edited_buffer: None,
2085        });
2086        cx.emit(Event::ExcerptsRemoved {
2087            ids,
2088            removed_buffer_ids,
2089        });
2090        cx.notify();
2091    }
2092
2093    pub fn excerpts_for_buffer(
2094        &self,
2095        buffer_id: BufferId,
2096        cx: &App,
2097    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2098        let mut excerpts = Vec::new();
2099        let snapshot = self.read(cx);
2100        let buffers = self.buffers.borrow();
2101        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2102        for locator in buffers
2103            .get(&buffer_id)
2104            .map(|state| &state.excerpts)
2105            .into_iter()
2106            .flatten()
2107        {
2108            cursor.seek_forward(&Some(locator), Bias::Left, &());
2109            if let Some(excerpt) = cursor.item() {
2110                if excerpt.locator == *locator {
2111                    excerpts.push((excerpt.id, excerpt.range.clone()));
2112                }
2113            }
2114        }
2115
2116        excerpts
2117    }
2118
2119    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2120        let snapshot = self.read(cx);
2121        let buffers = self.buffers.borrow();
2122        let mut excerpts = snapshot
2123            .excerpts
2124            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
2125        let mut diff_transforms = snapshot
2126            .diff_transforms
2127            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
2128        diff_transforms.next(&());
2129        let locators = buffers
2130            .get(&buffer_id)
2131            .into_iter()
2132            .flat_map(|state| &state.excerpts);
2133        let mut result = Vec::new();
2134        for locator in locators {
2135            excerpts.seek_forward(&Some(locator), Bias::Left, &());
2136            if let Some(excerpt) = excerpts.item() {
2137                if excerpt.locator == *locator {
2138                    let excerpt_start = excerpts.start().1.clone();
2139                    let excerpt_end =
2140                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2141
2142                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
2143                    let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2144                    let start = diff_transforms.start().1.0 + overshoot;
2145
2146                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
2147                    let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2148                    let end = diff_transforms.start().1.0 + overshoot;
2149
2150                    result.push(start..end)
2151                }
2152            }
2153        }
2154        result
2155    }
2156
2157    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2158        self.snapshot
2159            .borrow()
2160            .excerpts
2161            .iter()
2162            .map(|entry| entry.buffer_id)
2163            .collect()
2164    }
2165
2166    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2167        self.snapshot
2168            .borrow()
2169            .excerpts
2170            .iter()
2171            .map(|entry| entry.id)
2172            .collect()
2173    }
2174
2175    pub fn excerpt_containing(
2176        &self,
2177        position: impl ToOffset,
2178        cx: &App,
2179    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2180        let snapshot = self.read(cx);
2181        let offset = position.to_offset(&snapshot);
2182
2183        let mut cursor = snapshot.cursor::<usize>();
2184        cursor.seek(&offset);
2185        cursor
2186            .excerpt()
2187            .or_else(|| snapshot.excerpts.last())
2188            .map(|excerpt| {
2189                (
2190                    excerpt.id,
2191                    self.buffers
2192                        .borrow()
2193                        .get(&excerpt.buffer_id)
2194                        .unwrap()
2195                        .buffer
2196                        .clone(),
2197                    excerpt.range.context.clone(),
2198                )
2199            })
2200    }
2201
2202    // If point is at the end of the buffer, the last excerpt is returned
2203    pub fn point_to_buffer_offset<T: ToOffset>(
2204        &self,
2205        point: T,
2206        cx: &App,
2207    ) -> Option<(Entity<Buffer>, usize)> {
2208        let snapshot = self.read(cx);
2209        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2210        Some((
2211            self.buffers
2212                .borrow()
2213                .get(&buffer.remote_id())?
2214                .buffer
2215                .clone(),
2216            offset,
2217        ))
2218    }
2219
2220    // If point is at the end of the buffer, the last excerpt is returned
2221    pub fn point_to_buffer_point<T: ToPoint>(
2222        &self,
2223        point: T,
2224        cx: &App,
2225    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2226        let snapshot = self.read(cx);
2227        let (buffer, point, is_main_buffer) =
2228            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2229        Some((
2230            self.buffers
2231                .borrow()
2232                .get(&buffer.remote_id())?
2233                .buffer
2234                .clone(),
2235            point,
2236            is_main_buffer,
2237        ))
2238    }
2239
2240    pub fn buffer_point_to_anchor(
2241        &self,
2242        buffer: &Entity<Buffer>,
2243        point: Point,
2244        cx: &App,
2245    ) -> Option<Anchor> {
2246        let mut found = None;
2247        let snapshot = buffer.read(cx).snapshot();
2248        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2249            let start = range.context.start.to_point(&snapshot);
2250            let end = range.context.end.to_point(&snapshot);
2251            if start <= point && point < end {
2252                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2253                break;
2254            }
2255            if point < start {
2256                found = Some((start, excerpt_id));
2257            }
2258            if point > end {
2259                found = Some((end, excerpt_id));
2260            }
2261        }
2262
2263        found.map(|(point, excerpt_id)| {
2264            let text_anchor = snapshot.anchor_after(point);
2265            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2266        })
2267    }
2268
2269    pub fn remove_excerpts(
2270        &mut self,
2271        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2272        cx: &mut Context<Self>,
2273    ) {
2274        self.sync(cx);
2275        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2276        if ids.is_empty() {
2277            return;
2278        }
2279
2280        let mut buffers = self.buffers.borrow_mut();
2281        let mut snapshot = self.snapshot.borrow_mut();
2282        let mut new_excerpts = SumTree::default();
2283        let mut cursor = snapshot
2284            .excerpts
2285            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2286        let mut edits = Vec::new();
2287        let mut excerpt_ids = ids.iter().copied().peekable();
2288        let mut removed_buffer_ids = Vec::new();
2289
2290        while let Some(excerpt_id) = excerpt_ids.next() {
2291            self.paths_by_excerpt.remove(&excerpt_id);
2292            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2293            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2294            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2295
2296            if let Some(mut excerpt) = cursor.item() {
2297                if excerpt.id != excerpt_id {
2298                    continue;
2299                }
2300                let mut old_start = cursor.start().1;
2301
2302                // Skip over the removed excerpt.
2303                'remove_excerpts: loop {
2304                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2305                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2306                        if buffer_state.excerpts.is_empty() {
2307                            log::debug!(
2308                                "removing buffer and diff for buffer {}",
2309                                excerpt.buffer_id
2310                            );
2311                            buffers.remove(&excerpt.buffer_id);
2312                            removed_buffer_ids.push(excerpt.buffer_id);
2313                        }
2314                    }
2315                    cursor.next(&());
2316
2317                    // Skip over any subsequent excerpts that are also removed.
2318                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2319                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2320                        if let Some(next_excerpt) = cursor.item() {
2321                            if next_excerpt.locator == *next_locator {
2322                                excerpt_ids.next();
2323                                excerpt = next_excerpt;
2324                                continue 'remove_excerpts;
2325                            }
2326                        }
2327                    }
2328
2329                    break;
2330                }
2331
2332                // When removing the last excerpt, remove the trailing newline from
2333                // the previous excerpt.
2334                if cursor.item().is_none() && old_start.value > 0 {
2335                    old_start.value -= 1;
2336                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2337                }
2338
2339                // Push an edit for the removal of this run of excerpts.
2340                let old_end = cursor.start().1;
2341                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2342                edits.push(Edit {
2343                    old: old_start..old_end,
2344                    new: new_start..new_start,
2345                });
2346            }
2347        }
2348        let suffix = cursor.suffix(&());
2349        let changed_trailing_excerpt = suffix.is_empty();
2350        new_excerpts.append(suffix, &());
2351        drop(cursor);
2352        snapshot.excerpts = new_excerpts;
2353        for buffer_id in &removed_buffer_ids {
2354            self.diffs.remove(buffer_id);
2355            snapshot.diffs.remove(buffer_id);
2356        }
2357
2358        if changed_trailing_excerpt {
2359            snapshot.trailing_excerpt_update_count += 1;
2360        }
2361
2362        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2363        self.buffer_changed_since_sync.replace(true);
2364        cx.emit(Event::Edited {
2365            singleton_buffer_edited: false,
2366            edited_buffer: None,
2367        });
2368        cx.emit(Event::ExcerptsRemoved {
2369            ids,
2370            removed_buffer_ids,
2371        });
2372        cx.notify();
2373    }
2374
2375    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2376        &self,
2377        anchors: Anchors,
2378        cx: &mut Context<Self>,
2379    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2380        let borrow = self.buffers.borrow();
2381        let mut error = None;
2382        let mut futures = Vec::new();
2383        for anchor in anchors {
2384            if let Some(buffer_id) = anchor.buffer_id {
2385                if let Some(buffer) = borrow.get(&buffer_id) {
2386                    buffer.buffer.update(cx, |buffer, _| {
2387                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2388                    });
2389                } else {
2390                    error = Some(anyhow!(
2391                        "buffer {buffer_id} is not part of this multi-buffer"
2392                    ));
2393                    break;
2394                }
2395            }
2396        }
2397        async move {
2398            if let Some(error) = error {
2399                Err(error)?;
2400            }
2401            for future in futures {
2402                future.await?;
2403            }
2404            Ok(())
2405        }
2406    }
2407
2408    pub fn text_anchor_for_position<T: ToOffset>(
2409        &self,
2410        position: T,
2411        cx: &App,
2412    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2413        let snapshot = self.read(cx);
2414        let anchor = snapshot.anchor_before(position);
2415        let buffer = self
2416            .buffers
2417            .borrow()
2418            .get(&anchor.buffer_id?)?
2419            .buffer
2420            .clone();
2421        Some((buffer, anchor.text_anchor))
2422    }
2423
2424    fn on_buffer_event(
2425        &mut self,
2426        buffer: Entity<Buffer>,
2427        event: &language::BufferEvent,
2428        cx: &mut Context<Self>,
2429    ) {
2430        cx.emit(match event {
2431            language::BufferEvent::Edited => Event::Edited {
2432                singleton_buffer_edited: true,
2433                edited_buffer: Some(buffer.clone()),
2434            },
2435            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2436            language::BufferEvent::Saved => Event::Saved,
2437            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2438            language::BufferEvent::Reloaded => Event::Reloaded,
2439            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2440            language::BufferEvent::LanguageChanged => {
2441                Event::LanguageChanged(buffer.read(cx).remote_id())
2442            }
2443            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2444            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2445            language::BufferEvent::Closed => Event::Closed,
2446            language::BufferEvent::Discarded => Event::Discarded,
2447            language::BufferEvent::CapabilityChanged => {
2448                self.capability = buffer.read(cx).capability();
2449                Event::CapabilityChanged
2450            }
2451            language::BufferEvent::Operation { .. } => return,
2452        });
2453    }
2454
2455    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2456        self.sync(cx);
2457        let mut snapshot = self.snapshot.borrow_mut();
2458        let diff = diff.read(cx);
2459        let buffer_id = diff.buffer_id;
2460        let diff = diff.snapshot(cx);
2461        snapshot.diffs.insert(buffer_id, diff);
2462    }
2463
2464    fn buffer_diff_changed(
2465        &mut self,
2466        diff: Entity<BufferDiff>,
2467        range: Range<text::Anchor>,
2468        cx: &mut Context<Self>,
2469    ) {
2470        self.sync(cx);
2471        self.buffer_changed_since_sync.replace(true);
2472
2473        let diff = diff.read(cx);
2474        let buffer_id = diff.buffer_id;
2475        let buffers = self.buffers.borrow();
2476        let Some(buffer_state) = buffers.get(&buffer_id) else {
2477            return;
2478        };
2479
2480        let buffer = buffer_state.buffer.read(cx);
2481        let diff_change_range = range.to_offset(&buffer);
2482
2483        let new_diff = diff.snapshot(cx);
2484        let mut snapshot = self.snapshot.borrow_mut();
2485        let base_text_changed = snapshot
2486            .diffs
2487            .get(&buffer_id)
2488            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2489
2490        snapshot.diffs.insert(buffer_id, new_diff);
2491
2492        let mut excerpt_edits = Vec::new();
2493        for locator in &buffer_state.excerpts {
2494            let mut cursor = snapshot
2495                .excerpts
2496                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2497            cursor.seek_forward(&Some(locator), Bias::Left, &());
2498            if let Some(excerpt) = cursor.item() {
2499                if excerpt.locator == *locator {
2500                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2501                    if diff_change_range.end < excerpt_buffer_range.start
2502                        || diff_change_range.start > excerpt_buffer_range.end
2503                    {
2504                        continue;
2505                    }
2506                    let excerpt_start = cursor.start().1;
2507                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2508                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2509                        diff_change_range
2510                            .start
2511                            .saturating_sub(excerpt_buffer_range.start),
2512                    );
2513                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2514                        diff_change_range
2515                            .end
2516                            .saturating_sub(excerpt_buffer_range.start),
2517                    );
2518                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2519                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2520                    excerpt_edits.push(Edit {
2521                        old: edit_start..edit_end,
2522                        new: edit_start..edit_end,
2523                    });
2524                }
2525            }
2526        }
2527
2528        self.sync_diff_transforms(
2529            &mut snapshot,
2530            excerpt_edits,
2531            DiffChangeKind::DiffUpdated {
2532                base_changed: base_text_changed,
2533            },
2534        );
2535        cx.emit(Event::Edited {
2536            singleton_buffer_edited: false,
2537            edited_buffer: None,
2538        });
2539    }
2540
2541    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2542        self.buffers
2543            .borrow()
2544            .values()
2545            .map(|state| state.buffer.clone())
2546            .collect()
2547    }
2548
2549    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2550        self.buffers
2551            .borrow()
2552            .get(&buffer_id)
2553            .map(|state| state.buffer.clone())
2554    }
2555
2556    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2557        self.point_to_buffer_offset(point, cx)
2558            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2559    }
2560
2561    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2562        // let buffer_id = self
2563        //     .snapshot
2564        //     .borrow()
2565        //     .excerpts
2566        //     .first()
2567        //     .map(|excerpt| excerpt.buffer.remote_id());
2568        // buffer_id
2569        //     .and_then(|buffer_id| self.buffer(buffer_id))
2570        //     .map(|buffer| {
2571        //         let buffer = buffer.read(cx);
2572        //         language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2573        //     })
2574        //     .unwrap_or_else(move || self.language_settings_at(0, cx))
2575        todo!()
2576    }
2577
2578    pub fn language_settings_at<'a, T: ToOffset>(
2579        &'a self,
2580        point: T,
2581        cx: &'a App,
2582    ) -> Cow<'a, LanguageSettings> {
2583        let mut language = None;
2584        let mut file = None;
2585        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2586            let buffer = buffer.read(cx);
2587            language = buffer.language_at(offset);
2588            file = buffer.file();
2589        }
2590        // language_settings(language.map(|l| l.name()), file, cx)
2591        todo!()
2592    }
2593
2594    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2595        self.buffers
2596            .borrow()
2597            .values()
2598            .for_each(|state| f(&state.buffer))
2599    }
2600
2601    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2602        // if let Some(title) = self.title.as_ref() {
2603        //     return title.into();
2604        // }
2605
2606        // if let Some(buffer) = self.as_singleton() {
2607        //     let buffer = buffer.read(cx);
2608
2609        //     if let Some(file) = buffer.file() {
2610        //         return file.file_name(cx).to_string_lossy();
2611        //     }
2612
2613        //     if let Some(title) = self.buffer_content_title(&buffer) {
2614        //         return title;
2615        //     }
2616        // };
2617
2618        // "untitled".into()
2619        todo!()
2620    }
2621
2622    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2623        let mut is_leading_whitespace = true;
2624        let mut count = 0;
2625        let mut prev_was_space = false;
2626        let mut title = String::new();
2627
2628        for ch in buffer.snapshot().chars() {
2629            if is_leading_whitespace && ch.is_whitespace() {
2630                continue;
2631            }
2632
2633            is_leading_whitespace = false;
2634
2635            if ch == '\n' || count >= 40 {
2636                break;
2637            }
2638
2639            if ch.is_whitespace() {
2640                if !prev_was_space {
2641                    title.push(' ');
2642                    count += 1;
2643                    prev_was_space = true;
2644                }
2645            } else {
2646                title.push(ch);
2647                count += 1;
2648                prev_was_space = false;
2649            }
2650        }
2651
2652        let title = title.trim_end().to_string();
2653
2654        if title.is_empty() {
2655            return None;
2656        }
2657
2658        Some(title.into())
2659    }
2660
2661    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2662        self.title = Some(title);
2663        cx.notify();
2664    }
2665
2666    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2667    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2668        for buffer_state in self.buffers.borrow().values() {
2669            buffer_state
2670                .buffer
2671                .update(cx, |buffer, _cx| buffer.refresh_preview());
2672        }
2673    }
2674
2675    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2676    pub fn preserve_preview(&self, cx: &App) -> bool {
2677        self.buffers
2678            .borrow()
2679            .values()
2680            .all(|state| state.buffer.read(cx).preserve_preview())
2681    }
2682
2683    #[cfg(any(test, feature = "test-support"))]
2684    pub fn is_parsing(&self, cx: &App) -> bool {
2685        self.as_singleton().unwrap().read(cx).is_parsing()
2686    }
2687
2688    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2689        let buffer_id = diff.read(cx).buffer_id;
2690        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2691        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2692    }
2693
2694    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2695        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2696    }
2697
2698    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2699        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2700    }
2701
2702    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2703        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2704    }
2705
2706    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2707        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2708        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2709    }
2710
2711    pub fn all_diff_hunks_expanded(&self) -> bool {
2712        self.snapshot.borrow().all_diff_hunks_expanded
2713    }
2714
2715    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2716        self.snapshot.borrow_mut().all_diff_hunks_expanded = false;
2717        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2718    }
2719
2720    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2721        self.read(cx)
2722            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2723            .nth(1)
2724            .is_some()
2725    }
2726
2727    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2728        let snapshot = self.read(cx);
2729        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2730        let offset_range = range.to_offset(&snapshot);
2731        cursor.seek(&offset_range.start, Bias::Left, &());
2732        while let Some(item) = cursor.item() {
2733            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2734                break;
2735            }
2736            if item.hunk_info().is_some() {
2737                return true;
2738            }
2739            cursor.next(&());
2740        }
2741        false
2742    }
2743
2744    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2745        let snapshot = self.read(cx);
2746        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2747        for range in ranges {
2748            let range = range.to_point(&snapshot);
2749            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2750            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2751            let start = start.saturating_sub(1);
2752            let end = snapshot.len().min(end + 1);
2753            cursor.seek(&start, Bias::Right, &());
2754            while let Some(item) = cursor.item() {
2755                if *cursor.start() >= end {
2756                    break;
2757                }
2758                if item.hunk_info().is_some() {
2759                    return true;
2760                }
2761                cursor.next(&());
2762            }
2763        }
2764        false
2765    }
2766
2767    pub fn expand_or_collapse_diff_hunks_inner(
2768        &mut self,
2769        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2770        expand: bool,
2771        cx: &mut Context<Self>,
2772    ) {
2773        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2774            return;
2775        }
2776        self.sync(cx);
2777        let mut snapshot = self.snapshot.borrow_mut();
2778        let mut excerpt_edits = Vec::new();
2779        let mut last_hunk_row = None;
2780        for (range, end_excerpt_id) in ranges {
2781            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2782                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2783                    continue;
2784                }
2785                if last_hunk_row.map_or(false, |row| row >= diff_hunk.row_range.start) {
2786                    continue;
2787                }
2788                let start = Anchor::in_buffer(
2789                    diff_hunk.excerpt_id,
2790                    diff_hunk.buffer_id,
2791                    diff_hunk.buffer_range.start,
2792                );
2793                let end = Anchor::in_buffer(
2794                    diff_hunk.excerpt_id,
2795                    diff_hunk.buffer_id,
2796                    diff_hunk.buffer_range.end,
2797                );
2798                let start = snapshot.excerpt_offset_for_anchor(&start);
2799                let end = snapshot.excerpt_offset_for_anchor(&end);
2800                last_hunk_row = Some(diff_hunk.row_range.start);
2801                excerpt_edits.push(text::Edit {
2802                    old: start..end,
2803                    new: start..end,
2804                });
2805            }
2806        }
2807
2808        self.sync_diff_transforms(
2809            &mut snapshot,
2810            excerpt_edits,
2811            DiffChangeKind::ExpandOrCollapseHunks { expand },
2812        );
2813        cx.emit(Event::DiffHunksToggled);
2814        cx.emit(Event::Edited {
2815            singleton_buffer_edited: false,
2816            edited_buffer: None,
2817        });
2818    }
2819
2820    pub fn expand_or_collapse_diff_hunks(
2821        &mut self,
2822        ranges: Vec<Range<Anchor>>,
2823        expand: bool,
2824        cx: &mut Context<Self>,
2825    ) {
2826        let snapshot = self.snapshot.borrow().clone();
2827        let ranges = ranges.iter().map(move |range| {
2828            let end_excerpt_id = range.end.excerpt_id;
2829            let range = range.to_point(&snapshot);
2830            let mut peek_end = range.end;
2831            if range.end.row < snapshot.max_row().0 {
2832                peek_end = Point::new(range.end.row + 1, 0);
2833            };
2834            (range.start..peek_end, end_excerpt_id)
2835        });
2836        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2837    }
2838
2839    pub fn resize_excerpt(
2840        &mut self,
2841        id: ExcerptId,
2842        range: Range<text::Anchor>,
2843        cx: &mut Context<Self>,
2844    ) {
2845        self.sync(cx);
2846
2847        let mut snapshot = self.snapshot.borrow_mut();
2848        let locator = snapshot.excerpt_locator_for_id(id);
2849        let mut new_excerpts = SumTree::default();
2850        let mut cursor = snapshot
2851            .excerpts
2852            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2853        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2854
2855        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2856        new_excerpts.append(prefix, &());
2857
2858        let mut excerpt = cursor.item().unwrap().clone();
2859        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2860
2861        excerpt.range.context.start = range.start;
2862        excerpt.range.context.end = range.end;
2863        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2864
2865        excerpt.text_summary = excerpt
2866            .buffer
2867            .text_summary_for_range(excerpt.range.context.clone());
2868
2869        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2870        let old_start_offset = cursor.start().1;
2871        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2872        let edit = Edit {
2873            old: old_start_offset..old_start_offset + old_text_len,
2874            new: new_start_offset..new_start_offset + new_text_len,
2875        };
2876
2877        if let Some(last_edit) = edits.last_mut() {
2878            if last_edit.old.end == edit.old.start {
2879                last_edit.old.end = edit.old.end;
2880                last_edit.new.end = edit.new.end;
2881            } else {
2882                edits.push(edit);
2883            }
2884        } else {
2885            edits.push(edit);
2886        }
2887
2888        new_excerpts.push(excerpt, &());
2889
2890        cursor.next(&());
2891
2892        new_excerpts.append(cursor.suffix(&()), &());
2893
2894        drop(cursor);
2895        snapshot.excerpts = new_excerpts;
2896
2897        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2898        cx.emit(Event::Edited {
2899            singleton_buffer_edited: false,
2900            edited_buffer: None,
2901        });
2902        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2903        cx.notify();
2904    }
2905
2906    pub fn expand_excerpts(
2907        &mut self,
2908        ids: impl IntoIterator<Item = ExcerptId>,
2909        line_count: u32,
2910        direction: ExpandExcerptDirection,
2911        cx: &mut Context<Self>,
2912    ) {
2913        if line_count == 0 {
2914            return;
2915        }
2916        self.sync(cx);
2917        if !self.excerpts_by_path.is_empty() {
2918            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2919            return;
2920        }
2921        let mut snapshot = self.snapshot.borrow_mut();
2922
2923        let ids = ids.into_iter().collect::<Vec<_>>();
2924        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2925        let mut new_excerpts = SumTree::default();
2926        let mut cursor = snapshot
2927            .excerpts
2928            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2929        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2930
2931        for locator in &locators {
2932            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2933            new_excerpts.append(prefix, &());
2934
2935            let mut excerpt = cursor.item().unwrap().clone();
2936            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2937
2938            let up_line_count = if direction.should_expand_up() {
2939                line_count
2940            } else {
2941                0
2942            };
2943
2944            let start_row = excerpt
2945                .range
2946                .context
2947                .start
2948                .to_point(&excerpt.buffer)
2949                .row
2950                .saturating_sub(up_line_count);
2951            let start_point = Point::new(start_row, 0);
2952            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2953
2954            let down_line_count = if direction.should_expand_down() {
2955                line_count
2956            } else {
2957                0
2958            };
2959
2960            let mut end_point = excerpt.buffer.clip_point(
2961                excerpt.range.context.end.to_point(&excerpt.buffer)
2962                    + Point::new(down_line_count, 0),
2963                Bias::Left,
2964            );
2965            end_point.column = excerpt.buffer.line_len(end_point.row);
2966            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2967            excerpt.max_buffer_row = end_point.row;
2968
2969            excerpt.text_summary = excerpt
2970                .buffer
2971                .text_summary_for_range(excerpt.range.context.clone());
2972
2973            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2974            let old_start_offset = cursor.start().1;
2975            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2976            let edit = Edit {
2977                old: old_start_offset..old_start_offset + old_text_len,
2978                new: new_start_offset..new_start_offset + new_text_len,
2979            };
2980
2981            if let Some(last_edit) = edits.last_mut() {
2982                if last_edit.old.end == edit.old.start {
2983                    last_edit.old.end = edit.old.end;
2984                    last_edit.new.end = edit.new.end;
2985                } else {
2986                    edits.push(edit);
2987                }
2988            } else {
2989                edits.push(edit);
2990            }
2991
2992            new_excerpts.push(excerpt, &());
2993
2994            cursor.next(&());
2995        }
2996
2997        new_excerpts.append(cursor.suffix(&()), &());
2998
2999        drop(cursor);
3000        snapshot.excerpts = new_excerpts;
3001
3002        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3003        cx.emit(Event::Edited {
3004            singleton_buffer_edited: false,
3005            edited_buffer: None,
3006        });
3007        cx.emit(Event::ExcerptsExpanded { ids });
3008        cx.notify();
3009    }
3010
3011    fn sync(&self, cx: &App) {
3012        let changed = self.buffer_changed_since_sync.replace(false);
3013        if !changed {
3014            return;
3015        }
3016
3017        let mut snapshot = self.snapshot.borrow_mut();
3018        let mut excerpts_to_edit = Vec::new();
3019        let mut non_text_state_updated = false;
3020        let mut is_dirty = false;
3021        let mut has_deleted_file = false;
3022        let mut has_conflict = false;
3023        let mut edited = false;
3024        let mut buffers = self.buffers.borrow_mut();
3025        for buffer_state in buffers.values_mut() {
3026            let buffer = buffer_state.buffer.read(cx);
3027            let version = buffer.version();
3028            let non_text_state_update_count = buffer.non_text_state_update_count();
3029
3030            let buffer_edited = version.changed_since(&buffer_state.last_version);
3031            let buffer_non_text_state_updated =
3032                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
3033            if buffer_edited || buffer_non_text_state_updated {
3034                buffer_state.last_version = version;
3035                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
3036                excerpts_to_edit.extend(
3037                    buffer_state
3038                        .excerpts
3039                        .iter()
3040                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3041                );
3042            }
3043
3044            edited |= buffer_edited;
3045            non_text_state_updated |= buffer_non_text_state_updated;
3046            is_dirty |= buffer.is_dirty();
3047            has_deleted_file |= buffer
3048                .file()
3049                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
3050            has_conflict |= buffer.has_conflict();
3051        }
3052        if edited {
3053            snapshot.edit_count += 1;
3054        }
3055        if non_text_state_updated {
3056            snapshot.non_text_state_update_count += 1;
3057        }
3058        snapshot.is_dirty = is_dirty;
3059        snapshot.has_deleted_file = has_deleted_file;
3060        snapshot.has_conflict = has_conflict;
3061
3062        for (id, diff) in self.diffs.iter() {
3063            if snapshot.diffs.get(&id).is_none() {
3064                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3065            }
3066        }
3067
3068        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3069
3070        let mut edits = Vec::new();
3071        let mut new_excerpts = SumTree::default();
3072        let mut cursor = snapshot
3073            .excerpts
3074            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
3075
3076        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3077            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
3078            let old_excerpt = cursor.item().unwrap();
3079            let buffer = buffer.read(cx);
3080            let buffer_id = buffer.remote_id();
3081
3082            let mut new_excerpt;
3083            if buffer_edited {
3084                edits.extend(
3085                    buffer
3086                        .edits_since_in_range::<usize>(
3087                            old_excerpt.buffer.version(),
3088                            old_excerpt.range.context.clone(),
3089                        )
3090                        .map(|edit| {
3091                            let excerpt_old_start = cursor.start().1;
3092                            let excerpt_new_start =
3093                                ExcerptOffset::new(new_excerpts.summary().text.len);
3094                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3095                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3096                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3097                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3098                            Edit {
3099                                old: old_start..old_end,
3100                                new: new_start..new_end,
3101                            }
3102                        }),
3103                );
3104
3105                new_excerpt = Excerpt::new(
3106                    old_excerpt.id,
3107                    locator.clone(),
3108                    buffer_id,
3109                    buffer.snapshot(),
3110                    old_excerpt.range.clone(),
3111                    old_excerpt.has_trailing_newline,
3112                );
3113            } else {
3114                new_excerpt = old_excerpt.clone();
3115                new_excerpt.buffer = buffer.snapshot();
3116            }
3117
3118            new_excerpts.push(new_excerpt, &());
3119            cursor.next(&());
3120        }
3121        new_excerpts.append(cursor.suffix(&()), &());
3122
3123        drop(cursor);
3124        snapshot.excerpts = new_excerpts;
3125
3126        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3127    }
3128
3129    fn sync_diff_transforms(
3130        &self,
3131        snapshot: &mut MultiBufferSnapshot,
3132        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3133        change_kind: DiffChangeKind,
3134    ) {
3135        if excerpt_edits.is_empty() {
3136            return;
3137        }
3138
3139        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3140        let mut old_diff_transforms = snapshot
3141            .diff_transforms
3142            .cursor::<(ExcerptOffset, usize)>(&());
3143        let mut new_diff_transforms = SumTree::default();
3144        let mut old_expanded_hunks = HashSet::default();
3145        let mut output_edits = Vec::new();
3146        let mut output_delta = 0_isize;
3147        let mut at_transform_boundary = true;
3148        let mut end_of_current_insert = None;
3149
3150        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3151        while let Some(edit) = excerpt_edits.next() {
3152            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
3153            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3154                excerpts.prev(&());
3155            }
3156
3157            // Keep any transforms that are before the edit.
3158            if at_transform_boundary {
3159                at_transform_boundary = false;
3160                let transforms_before_edit =
3161                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3162                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3163                if let Some(transform) = old_diff_transforms.item() {
3164                    if old_diff_transforms.end(&()).0 == edit.old.start
3165                        && old_diff_transforms.start().0 < edit.old.start
3166                    {
3167                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3168                        old_diff_transforms.next(&());
3169                    }
3170                }
3171            }
3172
3173            // Compute the start of the edit in output coordinates.
3174            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3175            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3176            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3177
3178            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3179                &edit,
3180                &mut excerpts,
3181                &mut old_diff_transforms,
3182                &mut new_diff_transforms,
3183                &mut end_of_current_insert,
3184                &mut old_expanded_hunks,
3185                &snapshot,
3186                change_kind,
3187            );
3188
3189            // Compute the end of the edit in output coordinates.
3190            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3191            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3192            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3193            let edit_new_end =
3194                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3195            let output_edit = Edit {
3196                old: edit_old_start..edit_old_end,
3197                new: edit_new_start..edit_new_end,
3198            };
3199
3200            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3201            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3202            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3203                output_edits.push(output_edit);
3204            }
3205
3206            // If this is the last edit that intersects the current diff transform,
3207            // then recreate the content up to the end of this transform, to prepare
3208            // for reusing additional slices of the old transforms.
3209            if excerpt_edits.peek().map_or(true, |next_edit| {
3210                next_edit.old.start >= old_diff_transforms.end(&()).0
3211            }) {
3212                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3213                    && match old_diff_transforms.item() {
3214                        Some(DiffTransform::BufferContent {
3215                            inserted_hunk_info: Some(hunk),
3216                            ..
3217                        }) => excerpts.item().is_some_and(|excerpt| {
3218                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3219                        }),
3220                        _ => true,
3221                    };
3222
3223                let mut excerpt_offset = edit.new.end;
3224                if !keep_next_old_transform {
3225                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3226                    old_diff_transforms.next(&());
3227                }
3228
3229                old_expanded_hunks.clear();
3230                self.push_buffer_content_transform(
3231                    &snapshot,
3232                    &mut new_diff_transforms,
3233                    excerpt_offset,
3234                    end_of_current_insert,
3235                );
3236                at_transform_boundary = true;
3237            }
3238        }
3239
3240        // Keep any transforms that are after the last edit.
3241        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3242
3243        // Ensure there's always at least one buffer content transform.
3244        if new_diff_transforms.is_empty() {
3245            new_diff_transforms.push(
3246                DiffTransform::BufferContent {
3247                    summary: Default::default(),
3248                    inserted_hunk_info: None,
3249                },
3250                &(),
3251            );
3252        }
3253
3254        self.subscriptions.publish(output_edits);
3255        drop(old_diff_transforms);
3256        drop(excerpts);
3257        snapshot.diff_transforms = new_diff_transforms;
3258        snapshot.edit_count += 1;
3259
3260        #[cfg(any(test, feature = "test-support"))]
3261        snapshot.check_invariants();
3262    }
3263
3264    fn recompute_diff_transforms_for_edit(
3265        &self,
3266        edit: &Edit<TypedOffset<Excerpt>>,
3267        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3268        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3269        new_diff_transforms: &mut SumTree<DiffTransform>,
3270        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3271        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3272        snapshot: &MultiBufferSnapshot,
3273        change_kind: DiffChangeKind,
3274    ) -> bool {
3275        log::trace!(
3276            "recomputing diff transform for edit {:?} => {:?}",
3277            edit.old.start.value..edit.old.end.value,
3278            edit.new.start.value..edit.new.end.value
3279        );
3280
3281        // Record which hunks were previously expanded.
3282        while let Some(item) = old_diff_transforms.item() {
3283            if let Some(hunk_info) = item.hunk_info() {
3284                log::trace!(
3285                    "previously expanded hunk at {}",
3286                    old_diff_transforms.start().0
3287                );
3288                old_expanded_hunks.insert(hunk_info);
3289            }
3290            if old_diff_transforms.end(&()).0 > edit.old.end {
3291                break;
3292            }
3293            old_diff_transforms.next(&());
3294        }
3295
3296        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3297        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3298        if old_expanded_hunks.is_empty()
3299            && change_kind == DiffChangeKind::BufferEdited
3300            && !all_diff_hunks_expanded
3301        {
3302            return false;
3303        }
3304
3305        // Visit each excerpt that intersects the edit.
3306        let mut did_expand_hunks = false;
3307        while let Some(excerpt) = excerpts.item() {
3308            // Recompute the expanded hunks in the portion of the excerpt that
3309            // intersects the edit.
3310            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3311                let buffer = &excerpt.buffer;
3312                let excerpt_start = *excerpts.start();
3313                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3314                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3315                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3316                let edit_buffer_start =
3317                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3318                let edit_buffer_end =
3319                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3320                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3321                let edit_anchor_range =
3322                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3323
3324                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3325                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3326                        continue;
3327                    }
3328
3329                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3330                    if hunk_buffer_range.start < excerpt_buffer_start {
3331                        log::trace!("skipping hunk that starts before excerpt");
3332                        continue;
3333                    }
3334
3335                    let hunk_info = DiffTransformHunkInfo {
3336                        excerpt_id: excerpt.id,
3337                        hunk_start_anchor: hunk.buffer_range.start,
3338                        hunk_secondary_status: hunk.secondary_status,
3339                    };
3340
3341                    let hunk_excerpt_start = excerpt_start
3342                        + ExcerptOffset::new(
3343                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3344                        );
3345                    let hunk_excerpt_end = excerpt_end.min(
3346                        excerpt_start
3347                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3348                    );
3349
3350                    self.push_buffer_content_transform(
3351                        snapshot,
3352                        new_diff_transforms,
3353                        hunk_excerpt_start,
3354                        *end_of_current_insert,
3355                    );
3356
3357                    // For every existing hunk, determine if it was previously expanded
3358                    // and if it should currently be expanded.
3359                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3360                    let should_expand_hunk = match &change_kind {
3361                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3362                            was_previously_expanded || all_diff_hunks_expanded
3363                        }
3364                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3365                            let intersects = hunk_buffer_range.is_empty()
3366                                || hunk_buffer_range.end > edit_buffer_start;
3367                            if *expand {
3368                                intersects || was_previously_expanded || all_diff_hunks_expanded
3369                            } else {
3370                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3371                            }
3372                        }
3373                        _ => was_previously_expanded || all_diff_hunks_expanded,
3374                    };
3375
3376                    if should_expand_hunk {
3377                        did_expand_hunks = true;
3378                        log::trace!(
3379                            "expanding hunk {:?}, excerpt:{:?}",
3380                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3381                            excerpt.id
3382                        );
3383
3384                        if !hunk.diff_base_byte_range.is_empty()
3385                            && hunk_buffer_range.start >= edit_buffer_start
3386                            && hunk_buffer_range.start <= excerpt_buffer_end
3387                        {
3388                            let base_text = diff.base_text();
3389                            let mut text_cursor =
3390                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3391                            let mut base_text_summary =
3392                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3393
3394                            let mut has_trailing_newline = false;
3395                            if base_text_summary.last_line_chars > 0 {
3396                                base_text_summary += TextSummary::newline();
3397                                has_trailing_newline = true;
3398                            }
3399
3400                            new_diff_transforms.push(
3401                                DiffTransform::DeletedHunk {
3402                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3403                                    summary: base_text_summary,
3404                                    buffer_id: excerpt.buffer_id,
3405                                    hunk_info,
3406                                    has_trailing_newline,
3407                                },
3408                                &(),
3409                            );
3410                        }
3411
3412                        if !hunk_buffer_range.is_empty() {
3413                            *end_of_current_insert =
3414                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3415                        }
3416                    }
3417                }
3418            }
3419
3420            if excerpts.end(&()) <= edit.new.end {
3421                excerpts.next(&());
3422            } else {
3423                break;
3424            }
3425        }
3426
3427        did_expand_hunks || !old_expanded_hunks.is_empty()
3428    }
3429
3430    fn append_diff_transforms(
3431        &self,
3432        new_transforms: &mut SumTree<DiffTransform>,
3433        subtree: SumTree<DiffTransform>,
3434    ) {
3435        if let Some(DiffTransform::BufferContent {
3436            inserted_hunk_info,
3437            summary,
3438        }) = subtree.first()
3439        {
3440            if self.extend_last_buffer_content_transform(
3441                new_transforms,
3442                *inserted_hunk_info,
3443                *summary,
3444            ) {
3445                let mut cursor = subtree.cursor::<()>(&());
3446                cursor.next(&());
3447                cursor.next(&());
3448                new_transforms.append(cursor.suffix(&()), &());
3449                return;
3450            }
3451        }
3452        new_transforms.append(subtree, &());
3453    }
3454
3455    fn push_diff_transform(
3456        &self,
3457        new_transforms: &mut SumTree<DiffTransform>,
3458        transform: DiffTransform,
3459    ) {
3460        if let DiffTransform::BufferContent {
3461            inserted_hunk_info: inserted_hunk_anchor,
3462            summary,
3463        } = transform
3464        {
3465            if self.extend_last_buffer_content_transform(
3466                new_transforms,
3467                inserted_hunk_anchor,
3468                summary,
3469            ) {
3470                return;
3471            }
3472        }
3473        new_transforms.push(transform, &());
3474    }
3475
3476    fn push_buffer_content_transform(
3477        &self,
3478        old_snapshot: &MultiBufferSnapshot,
3479        new_transforms: &mut SumTree<DiffTransform>,
3480        end_offset: ExcerptOffset,
3481        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3482    ) {
3483        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3484            (end_offset.min(insertion_end_offset), Some(hunk_info))
3485        });
3486        let unchanged_region = [(end_offset, None)];
3487
3488        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3489        {
3490            let start_offset = new_transforms.summary().excerpt_len();
3491            if end_offset <= start_offset {
3492                continue;
3493            }
3494            let summary_to_add = old_snapshot
3495                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3496
3497            if !self.extend_last_buffer_content_transform(
3498                new_transforms,
3499                inserted_hunk_info,
3500                summary_to_add,
3501            ) {
3502                new_transforms.push(
3503                    DiffTransform::BufferContent {
3504                        summary: summary_to_add,
3505                        inserted_hunk_info,
3506                    },
3507                    &(),
3508                )
3509            }
3510        }
3511    }
3512
3513    fn extend_last_buffer_content_transform(
3514        &self,
3515        new_transforms: &mut SumTree<DiffTransform>,
3516        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3517        summary_to_add: TextSummary,
3518    ) -> bool {
3519        let mut did_extend = false;
3520        new_transforms.update_last(
3521            |last_transform| {
3522                if let DiffTransform::BufferContent {
3523                    summary,
3524                    inserted_hunk_info: inserted_hunk_anchor,
3525                } = last_transform
3526                {
3527                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3528                        *summary += summary_to_add;
3529                        did_extend = true;
3530                    }
3531                }
3532            },
3533            &(),
3534        );
3535        did_extend
3536    }
3537}
3538
3539fn build_excerpt_ranges(
3540    ranges: impl IntoIterator<Item = Range<Point>>,
3541    context_line_count: u32,
3542    buffer_snapshot: &BufferSnapshot,
3543) -> Vec<ExcerptRange<Point>> {
3544    ranges
3545        .into_iter()
3546        .map(|range| {
3547            let start_row = range.start.row.saturating_sub(context_line_count);
3548            let start = Point::new(start_row, 0);
3549            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3550            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3551            ExcerptRange {
3552                context: start..end,
3553                primary: range,
3554            }
3555        })
3556        .collect()
3557}
3558
3559#[cfg(any(test, feature = "test-support"))]
3560impl MultiBuffer {
3561    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3562        let buffer = cx.new(|cx| Buffer::local(text, cx));
3563        cx.new(|cx| Self::singleton(buffer, cx))
3564    }
3565
3566    pub fn build_multi<const COUNT: usize>(
3567        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3568        cx: &mut gpui::App,
3569    ) -> Entity<Self> {
3570        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3571        for (text, ranges) in excerpts {
3572            let buffer = cx.new(|cx| Buffer::local(text, cx));
3573            let excerpt_ranges = ranges
3574                .into_iter()
3575                .map(|range| ExcerptRange::new(range.clone()));
3576            multi.update(cx, |multi, cx| {
3577                multi.push_excerpts(buffer, excerpt_ranges, cx)
3578            });
3579        }
3580
3581        multi
3582    }
3583
3584    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3585        cx.new(|cx| Self::singleton(buffer, cx))
3586    }
3587
3588    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3589        cx.new(|cx| {
3590            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3591            let mutation_count = rng.gen_range(1..=5);
3592            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3593            multibuffer
3594        })
3595    }
3596
3597    pub fn randomly_edit(
3598        &mut self,
3599        rng: &mut impl rand::Rng,
3600        edit_count: usize,
3601        cx: &mut Context<Self>,
3602    ) {
3603        use util::RandomCharIter;
3604
3605        let snapshot = self.read(cx);
3606        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3607        let mut last_end = None;
3608        for _ in 0..edit_count {
3609            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3610                break;
3611            }
3612
3613            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3614            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3615            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3616            last_end = Some(end);
3617
3618            let mut range = start..end;
3619            if rng.gen_bool(0.2) {
3620                mem::swap(&mut range.start, &mut range.end);
3621            }
3622
3623            let new_text_len = rng.gen_range(0..10);
3624            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3625
3626            edits.push((range, new_text.into()));
3627        }
3628        log::info!("mutating multi-buffer with {:?}", edits);
3629        drop(snapshot);
3630
3631        self.edit(edits, None, cx);
3632    }
3633
3634    pub fn randomly_edit_excerpts(
3635        &mut self,
3636        rng: &mut impl rand::Rng,
3637        mutation_count: usize,
3638        cx: &mut Context<Self>,
3639    ) {
3640        use rand::prelude::*;
3641        use std::env;
3642        use util::RandomCharIter;
3643
3644        let max_excerpts = env::var("MAX_EXCERPTS")
3645            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3646            .unwrap_or(5);
3647
3648        let mut buffers = Vec::new();
3649        for _ in 0..mutation_count {
3650            if rng.gen_bool(0.05) {
3651                log::info!("Clearing multi-buffer");
3652                self.clear(cx);
3653                continue;
3654            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3655                let ids = self.excerpt_ids();
3656                let mut excerpts = HashSet::default();
3657                for _ in 0..rng.gen_range(0..ids.len()) {
3658                    excerpts.extend(ids.choose(rng).copied());
3659                }
3660
3661                let line_count = rng.gen_range(0..5);
3662
3663                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3664
3665                self.expand_excerpts(
3666                    excerpts.iter().cloned(),
3667                    line_count,
3668                    ExpandExcerptDirection::UpAndDown,
3669                    cx,
3670                );
3671                continue;
3672            }
3673
3674            let excerpt_ids = self.excerpt_ids();
3675            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3676                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3677                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3678                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3679                    let buffer = buffers.last().unwrap().read(cx);
3680                    log::info!(
3681                        "Creating new buffer {} with text: {:?}",
3682                        buffer.remote_id(),
3683                        buffer.text()
3684                    );
3685                    buffers.last().unwrap().clone()
3686                } else {
3687                    self.buffers
3688                        .borrow()
3689                        .values()
3690                        .choose(rng)
3691                        .unwrap()
3692                        .buffer
3693                        .clone()
3694                };
3695
3696                let buffer = buffer_handle.read(cx);
3697                let buffer_text = buffer.text();
3698                let ranges = (0..rng.gen_range(0..5))
3699                    .map(|_| {
3700                        let end_ix =
3701                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3702                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3703                        ExcerptRange::new(start_ix..end_ix)
3704                    })
3705                    .collect::<Vec<_>>();
3706                log::info!(
3707                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3708                    buffer_handle.read(cx).remote_id(),
3709                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3710                    ranges
3711                        .iter()
3712                        .map(|r| &buffer_text[r.context.clone()])
3713                        .collect::<Vec<_>>()
3714                );
3715
3716                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3717                log::info!("Inserted with ids: {:?}", excerpt_id);
3718            } else {
3719                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3720                let mut excerpts_to_remove = excerpt_ids
3721                    .choose_multiple(rng, remove_count)
3722                    .cloned()
3723                    .collect::<Vec<_>>();
3724                let snapshot = self.snapshot.borrow();
3725                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3726                drop(snapshot);
3727                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3728                self.remove_excerpts(excerpts_to_remove, cx);
3729            }
3730        }
3731    }
3732
3733    pub fn randomly_mutate(
3734        &mut self,
3735        rng: &mut impl rand::Rng,
3736        mutation_count: usize,
3737        cx: &mut Context<Self>,
3738    ) {
3739        use rand::prelude::*;
3740
3741        if rng.gen_bool(0.7) || self.singleton {
3742            let buffer = self
3743                .buffers
3744                .borrow()
3745                .values()
3746                .choose(rng)
3747                .map(|state| state.buffer.clone());
3748
3749            if let Some(buffer) = buffer {
3750                buffer.update(cx, |buffer, cx| {
3751                    if rng.r#gen() {
3752                        buffer.randomly_edit(rng, mutation_count, cx);
3753                    } else {
3754                        buffer.randomly_undo_redo(rng, cx);
3755                    }
3756                });
3757            } else {
3758                self.randomly_edit(rng, mutation_count, cx);
3759            }
3760        } else {
3761            self.randomly_edit_excerpts(rng, mutation_count, cx);
3762        }
3763
3764        self.check_invariants(cx);
3765    }
3766
3767    fn check_invariants(&self, cx: &App) {
3768        self.read(cx).check_invariants();
3769    }
3770}
3771
3772impl EventEmitter<Event> for MultiBuffer {}
3773
3774impl MultiBufferSnapshot {
3775    pub fn text(&self) -> String {
3776        self.chunks(0..self.len(), false)
3777            .map(|chunk| chunk.text)
3778            .collect()
3779    }
3780
3781    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3782        self.reversed_chunks_in_range(0..position.to_offset(self))
3783            .flat_map(|c| c.chars().rev())
3784    }
3785
3786    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3787        let mut cursor = self.cursor::<usize>();
3788        cursor.seek(&range.end);
3789        let current_chunks = cursor.region().as_ref().map(|region| {
3790            let start_overshoot = range.start.saturating_sub(region.range.start);
3791            let end_overshoot = range.end - region.range.start;
3792            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3793            let start = region.buffer_range.start + start_overshoot;
3794            region.buffer.reversed_chunks_in_range(start..end)
3795        });
3796        ReversedMultiBufferChunks {
3797            cursor,
3798            current_chunks,
3799            start: range.start,
3800            offset: range.end,
3801        }
3802    }
3803
3804    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3805        let offset = position.to_offset(self);
3806        self.text_for_range(offset..self.len())
3807            .flat_map(|chunk| chunk.chars())
3808    }
3809
3810    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3811        self.chunks(range, false).map(|chunk| chunk.text)
3812    }
3813
3814    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3815        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3816            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3817    }
3818
3819    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3820    where
3821        T: ToOffset,
3822    {
3823        let position = position.to_offset(self);
3824        position == self.clip_offset(position, Bias::Left)
3825            && self
3826                .bytes_in_range(position..self.len())
3827                .flatten()
3828                .copied()
3829                .take(needle.len())
3830                .eq(needle.bytes())
3831    }
3832
3833    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3834        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3835    }
3836
3837    pub fn diff_hunks_in_range<T: ToPoint>(
3838        &self,
3839        range: Range<T>,
3840    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3841        let query_range = range.start.to_point(self)..range.end.to_point(self);
3842        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3843            let diff = self.diffs.get(&buffer.remote_id())?;
3844            let buffer_start = buffer.anchor_before(buffer_range.start);
3845            let buffer_end = buffer.anchor_after(buffer_range.end);
3846            Some(
3847                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3848                    .filter_map(|hunk| {
3849                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3850                            return None;
3851                        }
3852                        Some((hunk.range.clone(), hunk))
3853                    }),
3854            )
3855        })
3856        .filter_map(move |(range, hunk, excerpt)| {
3857            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3858            {
3859                return None;
3860            }
3861            let end_row = if range.end.column == 0 {
3862                range.end.row
3863            } else {
3864                range.end.row + 1
3865            };
3866            Some(MultiBufferDiffHunk {
3867                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3868                buffer_id: excerpt.buffer_id,
3869                excerpt_id: excerpt.id,
3870                buffer_range: hunk.buffer_range.clone(),
3871                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3872                secondary_status: hunk.secondary_status,
3873            })
3874        })
3875    }
3876
3877    pub fn excerpt_ids_for_range<T: ToOffset>(
3878        &self,
3879        range: Range<T>,
3880    ) -> impl Iterator<Item = ExcerptId> + '_ {
3881        let range = range.start.to_offset(self)..range.end.to_offset(self);
3882        let mut cursor = self.cursor::<usize>();
3883        cursor.seek(&range.start);
3884        std::iter::from_fn(move || {
3885            let region = cursor.region()?;
3886            if region.range.start >= range.end {
3887                return None;
3888            }
3889            cursor.next_excerpt();
3890            Some(region.excerpt.id)
3891        })
3892    }
3893
3894    pub fn buffer_ids_for_range<T: ToOffset>(
3895        &self,
3896        range: Range<T>,
3897    ) -> impl Iterator<Item = BufferId> + '_ {
3898        let range = range.start.to_offset(self)..range.end.to_offset(self);
3899        let mut cursor = self.cursor::<usize>();
3900        cursor.seek(&range.start);
3901        std::iter::from_fn(move || {
3902            let region = cursor.region()?;
3903            if region.range.start > range.end
3904                || region.range.start == range.end && region.range.start > range.start
3905            {
3906                return None;
3907            }
3908            cursor.next_excerpt();
3909            Some(region.excerpt.buffer_id)
3910        })
3911    }
3912
3913    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3914        &self,
3915        ranges: impl Iterator<Item = Range<T>>,
3916    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3917        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3918    }
3919
3920    pub fn range_to_buffer_ranges<T: ToOffset>(
3921        &self,
3922        range: Range<T>,
3923    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3924        let start = range.start.to_offset(&self);
3925        let end = range.end.to_offset(&self);
3926
3927        let mut cursor = self.cursor::<usize>();
3928        cursor.seek(&start);
3929
3930        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3931        while let Some(region) = cursor.region() {
3932            if region.range.start > end {
3933                break;
3934            }
3935            if region.is_main_buffer {
3936                let start_overshoot = start.saturating_sub(region.range.start);
3937                let end_overshoot = end.saturating_sub(region.range.start);
3938                let start = region
3939                    .buffer_range
3940                    .end
3941                    .min(region.buffer_range.start + start_overshoot);
3942                let end = region
3943                    .buffer_range
3944                    .end
3945                    .min(region.buffer_range.start + end_overshoot);
3946                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3947                    *excerpt_id == region.excerpt.id && prev_range.end == start
3948                }) {
3949                    prev.1.end = end;
3950                } else {
3951                    result.push((region.buffer, start..end, region.excerpt.id));
3952                }
3953            }
3954            cursor.next();
3955        }
3956        result
3957    }
3958
3959    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3960        &self,
3961        range: Range<T>,
3962    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3963        let start = range.start.to_offset(&self);
3964        let end = range.end.to_offset(&self);
3965
3966        let mut cursor = self.cursor::<usize>();
3967        cursor.seek(&start);
3968
3969        std::iter::from_fn(move || {
3970            let region = cursor.region()?;
3971            if region.range.start > end {
3972                return None;
3973            }
3974            let start_overshoot = start.saturating_sub(region.range.start);
3975            let end_overshoot = end.saturating_sub(region.range.start);
3976            let start = region
3977                .buffer_range
3978                .end
3979                .min(region.buffer_range.start + start_overshoot);
3980            let end = region
3981                .buffer_range
3982                .end
3983                .min(region.buffer_range.start + end_overshoot);
3984
3985            let region_excerpt_id = region.excerpt.id;
3986            let deleted_hunk_anchor = if region.is_main_buffer {
3987                None
3988            } else {
3989                Some(self.anchor_before(region.range.start))
3990            };
3991            let result = (
3992                region.buffer,
3993                start..end,
3994                region_excerpt_id,
3995                deleted_hunk_anchor,
3996            );
3997            cursor.next();
3998            Some(result)
3999        })
4000    }
4001
4002    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4003    /// coordinates.
4004    ///
4005    /// The given callback will be called for every excerpt intersecting the given range. It will
4006    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4007    /// The callback should return an iterator of metadata items from that buffer, each paired
4008    /// with a buffer range.
4009    ///
4010    /// The returned iterator yields each of these metadata items, paired with its range in
4011    /// multi-buffer coordinates.
4012    fn lift_buffer_metadata<'a, D, M, I>(
4013        &'a self,
4014        query_range: Range<D>,
4015        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
4016    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
4017    where
4018        I: Iterator<Item = (Range<D>, M)> + 'a,
4019        D: TextDimension + Ord + Sub<D, Output = D>,
4020    {
4021        let max_position = D::from_text_summary(&self.text_summary());
4022        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4023        let mut cursor = self.cursor::<D>();
4024
4025        // Find the excerpt and buffer offset where the given range ends.
4026        cursor.seek(&query_range.end);
4027        let mut range_end = None;
4028        while let Some(region) = cursor.region() {
4029            if region.is_main_buffer {
4030                let mut buffer_end = region.buffer_range.start;
4031                let overshoot = if query_range.end > region.range.start {
4032                    query_range.end - region.range.start
4033                } else {
4034                    D::default()
4035                };
4036                buffer_end.add_assign(&overshoot);
4037                range_end = Some((region.excerpt.id, buffer_end));
4038                break;
4039            }
4040            cursor.next();
4041        }
4042
4043        cursor.seek(&query_range.start);
4044
4045        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
4046            if region.range.start > D::zero(&()) {
4047                cursor.prev()
4048            }
4049        }
4050
4051        iter::from_fn(move || {
4052            loop {
4053                let excerpt = cursor.excerpt()?;
4054
4055                // If we have already retrieved metadata for this excerpt, continue to use it.
4056                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4057                    .as_mut()
4058                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4059                {
4060                    Some(metadata)
4061                }
4062                // Otherwise, compute the intersection of the input range with the excerpt's range,
4063                // and retrieve the metadata for the resulting range.
4064                else {
4065                    let region = cursor.region()?;
4066                    let mut buffer_start;
4067                    if region.is_main_buffer {
4068                        buffer_start = region.buffer_range.start;
4069                        if query_range.start > region.range.start {
4070                            let overshoot = query_range.start - region.range.start;
4071                            buffer_start.add_assign(&overshoot);
4072                        }
4073                        buffer_start = buffer_start.min(region.buffer_range.end);
4074                    } else {
4075                        buffer_start = cursor.main_buffer_position()?;
4076                    };
4077                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4078                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
4079                        if excerpt.id == end_excerpt_id {
4080                            buffer_end = buffer_end.min(end_buffer_offset);
4081                        }
4082                    }
4083
4084                    if let Some(iterator) =
4085                        get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
4086                    {
4087                        Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
4088                    } else {
4089                        None
4090                    }
4091                };
4092
4093                // Visit each metadata item.
4094                if let Some((metadata_buffer_range, metadata)) =
4095                    metadata_iter.and_then(Iterator::next)
4096                {
4097                    // Find the multibuffer regions that contain the start and end of
4098                    // the metadata item's range.
4099                    if metadata_buffer_range.start > D::default() {
4100                        while let Some(region) = cursor.region() {
4101                            if region.is_main_buffer
4102                                && (region.buffer_range.end >= metadata_buffer_range.start
4103                                    || cursor.is_at_end_of_excerpt())
4104                            {
4105                                break;
4106                            }
4107                            cursor.next();
4108                        }
4109                    }
4110                    let start_region = cursor.region()?;
4111                    while let Some(region) = cursor.region() {
4112                        if region.is_main_buffer
4113                            && (region.buffer_range.end > metadata_buffer_range.end
4114                                || cursor.is_at_end_of_excerpt())
4115                        {
4116                            break;
4117                        }
4118                        cursor.next();
4119                    }
4120                    let end_region = cursor.region();
4121
4122                    // Convert the metadata item's range into multibuffer coordinates.
4123                    let mut start_position = start_region.range.start;
4124                    let region_buffer_start = start_region.buffer_range.start;
4125                    if start_region.is_main_buffer
4126                        && metadata_buffer_range.start > region_buffer_start
4127                    {
4128                        start_position
4129                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4130                        start_position = start_position.min(start_region.range.end);
4131                    }
4132
4133                    let mut end_position = max_position;
4134                    if let Some(end_region) = &end_region {
4135                        end_position = end_region.range.start;
4136                        debug_assert!(end_region.is_main_buffer);
4137                        let region_buffer_start = end_region.buffer_range.start;
4138                        if metadata_buffer_range.end > region_buffer_start {
4139                            end_position
4140                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4141                        }
4142                        end_position = end_position.min(end_region.range.end);
4143                    }
4144
4145                    if start_position <= query_range.end && end_position >= query_range.start {
4146                        return Some((start_position..end_position, metadata, excerpt));
4147                    }
4148                }
4149                // When there are no more metadata items for this excerpt, move to the next excerpt.
4150                else {
4151                    current_excerpt_metadata.take();
4152                    if let Some((end_excerpt_id, _)) = range_end {
4153                        if excerpt.id == end_excerpt_id {
4154                            return None;
4155                        }
4156                    }
4157                    cursor.next_excerpt();
4158                }
4159            }
4160        })
4161    }
4162
4163    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4164        let offset = position.to_offset(self);
4165
4166        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4167        cursor.seek(&DimensionPair {
4168            key: offset,
4169            value: None,
4170        });
4171        cursor.seek_to_start_of_current_excerpt();
4172        let excerpt = cursor.excerpt()?;
4173
4174        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4175        let current_position = self
4176            .anchor_before(offset)
4177            .text_anchor
4178            .to_offset(&excerpt.buffer);
4179        let excerpt_end = excerpt
4180            .buffer
4181            .anchor_before(excerpt_end.min(current_position));
4182
4183        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4184            for hunk in diff.hunks_intersecting_range_rev(
4185                excerpt.range.context.start..excerpt_end,
4186                &excerpt.buffer,
4187            ) {
4188                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4189                if hunk_end >= current_position {
4190                    continue;
4191                }
4192                let start =
4193                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4194                        .to_point(&self);
4195                return Some(MultiBufferRow(start.row));
4196            }
4197        }
4198
4199        loop {
4200            cursor.prev_excerpt();
4201            let excerpt = cursor.excerpt()?;
4202
4203            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4204                continue;
4205            };
4206            let mut hunks =
4207                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4208            let Some(hunk) = hunks.next() else {
4209                continue;
4210            };
4211            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4212                .to_point(&self);
4213            return Some(MultiBufferRow(start.row));
4214        }
4215    }
4216
4217    pub fn has_diff_hunks(&self) -> bool {
4218        self.diffs.values().any(|diff| !diff.is_empty())
4219    }
4220
4221    pub fn is_inside_word<T: ToOffset>(&self, position: T, for_completion: bool) -> bool {
4222        let position = position.to_offset(self);
4223        let classifier = self
4224            .char_classifier_at(position)
4225            .for_completion(for_completion);
4226        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4227        let prev_char_kind = self
4228            .reversed_chars_at(position)
4229            .next()
4230            .map(|c| classifier.kind(c));
4231        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4232    }
4233
4234    pub fn surrounding_word<T: ToOffset>(
4235        &self,
4236        start: T,
4237        for_completion: bool,
4238    ) -> (Range<usize>, Option<CharKind>) {
4239        let mut start = start.to_offset(self);
4240        let mut end = start;
4241        let mut next_chars = self.chars_at(start).peekable();
4242        let mut prev_chars = self.reversed_chars_at(start).peekable();
4243
4244        let classifier = self
4245            .char_classifier_at(start)
4246            .for_completion(for_completion);
4247
4248        let word_kind = cmp::max(
4249            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4250            next_chars.peek().copied().map(|c| classifier.kind(c)),
4251        );
4252
4253        for ch in prev_chars {
4254            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4255                start -= ch.len_utf8();
4256            } else {
4257                break;
4258            }
4259        }
4260
4261        for ch in next_chars {
4262            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4263                end += ch.len_utf8();
4264            } else {
4265                break;
4266            }
4267        }
4268
4269        (start..end, word_kind)
4270    }
4271
4272    pub fn char_kind_before<T: ToOffset>(
4273        &self,
4274        start: T,
4275        for_completion: bool,
4276    ) -> Option<CharKind> {
4277        let start = start.to_offset(self);
4278        let classifier = self
4279            .char_classifier_at(start)
4280            .for_completion(for_completion);
4281        self.reversed_chars_at(start)
4282            .next()
4283            .map(|ch| classifier.kind(ch))
4284    }
4285
4286    pub fn is_singleton(&self) -> bool {
4287        self.singleton
4288    }
4289
4290    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4291        if self.singleton {
4292            self.excerpts
4293                .iter()
4294                .next()
4295                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4296        } else {
4297            None
4298        }
4299    }
4300
4301    pub fn len(&self) -> usize {
4302        self.diff_transforms.summary().output.len
4303    }
4304
4305    pub fn is_empty(&self) -> bool {
4306        self.excerpts.summary().text.len == 0
4307    }
4308
4309    pub fn widest_line_number(&self) -> u32 {
4310        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4311        self.excerpts.summary().widest_line_number + 1
4312    }
4313
4314    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4315        let range = range.start.to_offset(self)..range.end.to_offset(self);
4316        let mut excerpts = self.cursor::<usize>();
4317        excerpts.seek(&range.start);
4318
4319        let mut chunk;
4320        let mut has_trailing_newline;
4321        let excerpt_bytes;
4322        if let Some(region) = excerpts.region() {
4323            let mut bytes = region.buffer.bytes_in_range(
4324                region.buffer_range.start + range.start - region.range.start
4325                    ..(region.buffer_range.start + range.end - region.range.start)
4326                        .min(region.buffer_range.end),
4327            );
4328            chunk = bytes.next().unwrap_or(&[][..]);
4329            excerpt_bytes = Some(bytes);
4330            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4331            if chunk.is_empty() && has_trailing_newline {
4332                chunk = b"\n";
4333                has_trailing_newline = false;
4334            }
4335        } else {
4336            chunk = &[][..];
4337            excerpt_bytes = None;
4338            has_trailing_newline = false;
4339        };
4340
4341        MultiBufferBytes {
4342            range,
4343            cursor: excerpts,
4344            excerpt_bytes,
4345            has_trailing_newline,
4346            chunk,
4347        }
4348    }
4349
4350    pub fn reversed_bytes_in_range<T: ToOffset>(
4351        &self,
4352        range: Range<T>,
4353    ) -> ReversedMultiBufferBytes<'_> {
4354        let range = range.start.to_offset(self)..range.end.to_offset(self);
4355        let mut chunks = self.reversed_chunks_in_range(range.clone());
4356        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4357        ReversedMultiBufferBytes {
4358            range,
4359            chunks,
4360            chunk,
4361        }
4362    }
4363
4364    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4365        let mut cursor = self.cursor::<Point>();
4366        cursor.seek(&Point::new(start_row.0, 0));
4367        let mut result = MultiBufferRows {
4368            point: Point::new(0, 0),
4369            is_empty: self.excerpts.is_empty(),
4370            is_singleton: self.is_singleton(),
4371            cursor,
4372        };
4373        result.seek(start_row);
4374        result
4375    }
4376
4377    pub fn chunks<T: ToOffset>(
4378        &self,
4379        range: Range<T>,
4380        language_aware: bool,
4381    ) -> MultiBufferChunks<'_> {
4382        let mut chunks = MultiBufferChunks {
4383            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4384            range: 0..0,
4385            excerpts: self.excerpts.cursor(&()),
4386            diff_transforms: self.diff_transforms.cursor(&()),
4387            diffs: &self.diffs,
4388            diff_base_chunks: None,
4389            excerpt_chunks: None,
4390            buffer_chunk: None,
4391            language_aware,
4392        };
4393        let range = range.start.to_offset(self)..range.end.to_offset(self);
4394        chunks.seek(range);
4395        chunks
4396    }
4397
4398    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4399        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4400    }
4401
4402    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4403        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4404    }
4405
4406    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4407        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4408    }
4409
4410    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4411        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4412            buffer.clip_point_utf16(Unclipped(point), bias)
4413        })
4414    }
4415
4416    pub fn offset_to_point(&self, offset: usize) -> Point {
4417        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4418    }
4419
4420    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4421        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4422    }
4423
4424    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4425        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4426    }
4427
4428    pub fn point_to_offset(&self, point: Point) -> usize {
4429        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4430    }
4431
4432    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4433        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4434    }
4435
4436    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4437        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4438    }
4439
4440    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4441        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4442    }
4443
4444    fn clip_dimension<D>(
4445        &self,
4446        position: D,
4447        bias: Bias,
4448        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4449    ) -> D
4450    where
4451        D: TextDimension + Ord + Sub<D, Output = D>,
4452    {
4453        let mut cursor = self.cursor();
4454        cursor.seek(&position);
4455        if let Some(region) = cursor.region() {
4456            if position >= region.range.end {
4457                return region.range.end;
4458            }
4459            let overshoot = position - region.range.start;
4460            let mut buffer_position = region.buffer_range.start;
4461            buffer_position.add_assign(&overshoot);
4462            let clipped_buffer_position =
4463                clip_buffer_position(&region.buffer, buffer_position, bias);
4464            let mut position = region.range.start;
4465            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4466            position
4467        } else {
4468            D::from_text_summary(&self.text_summary())
4469        }
4470    }
4471
4472    fn convert_dimension<D1, D2>(
4473        &self,
4474        key: D1,
4475        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4476    ) -> D2
4477    where
4478        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4479        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4480    {
4481        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4482        cursor.seek(&DimensionPair { key, value: None });
4483        if let Some(region) = cursor.region() {
4484            if key >= region.range.end.key {
4485                return region.range.end.value.unwrap();
4486            }
4487            let start_key = region.range.start.key;
4488            let start_value = region.range.start.value.unwrap();
4489            let buffer_start_key = region.buffer_range.start.key;
4490            let buffer_start_value = region.buffer_range.start.value.unwrap();
4491            let mut buffer_key = buffer_start_key;
4492            buffer_key.add_assign(&(key - start_key));
4493            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4494            let mut result = start_value;
4495            result.add_assign(&(buffer_value - buffer_start_value));
4496            result
4497        } else {
4498            D2::from_text_summary(&self.text_summary())
4499        }
4500    }
4501
4502    pub fn point_to_buffer_offset<T: ToOffset>(
4503        &self,
4504        point: T,
4505    ) -> Option<(&BufferSnapshot, usize)> {
4506        let offset = point.to_offset(self);
4507        let mut cursor = self.cursor::<usize>();
4508        cursor.seek(&offset);
4509        let region = cursor.region()?;
4510        let overshoot = offset - region.range.start;
4511        let buffer_offset = region.buffer_range.start + overshoot;
4512        if buffer_offset == region.buffer.len() + 1
4513            && region.has_trailing_newline
4514            && !region.is_main_buffer
4515        {
4516            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4517        } else if buffer_offset > region.buffer.len() {
4518            return None;
4519        }
4520        Some((region.buffer, buffer_offset))
4521    }
4522
4523    pub fn point_to_buffer_point(
4524        &self,
4525        point: Point,
4526    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4527        let mut cursor = self.cursor::<Point>();
4528        cursor.seek(&point);
4529        let region = cursor.region()?;
4530        let overshoot = point - region.range.start;
4531        let buffer_point = region.buffer_range.start + overshoot;
4532        let excerpt = cursor.excerpt()?;
4533        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4534            && region.has_trailing_newline
4535            && !region.is_main_buffer
4536        {
4537            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4538        } else if buffer_point > region.buffer.max_point() {
4539            return None;
4540        }
4541        Some((region.buffer, buffer_point, excerpt.id))
4542    }
4543
4544    pub fn suggested_indents(
4545        &self,
4546        rows: impl IntoIterator<Item = u32>,
4547        cx: &App,
4548    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4549        let mut result = BTreeMap::new();
4550
4551        let mut rows_for_excerpt = Vec::new();
4552        let mut cursor = self.cursor::<Point>();
4553        let mut rows = rows.into_iter().peekable();
4554        let mut prev_row = u32::MAX;
4555        let mut prev_language_indent_size = IndentSize::default();
4556
4557        while let Some(row) = rows.next() {
4558            cursor.seek(&Point::new(row, 0));
4559            let Some(region) = cursor.region() else {
4560                continue;
4561            };
4562
4563            // Retrieve the language and indent size once for each disjoint region being indented.
4564            let single_indent_size = if row.saturating_sub(1) == prev_row {
4565                prev_language_indent_size
4566            } else {
4567                region
4568                    .buffer
4569                    .language_indent_size_at(Point::new(row, 0), cx)
4570            };
4571            prev_language_indent_size = single_indent_size;
4572            prev_row = row;
4573
4574            let start_buffer_row = region.buffer_range.start.row;
4575            let start_multibuffer_row = region.range.start.row;
4576            let end_multibuffer_row = region.range.end.row;
4577
4578            rows_for_excerpt.push(row);
4579            while let Some(next_row) = rows.peek().copied() {
4580                if end_multibuffer_row > next_row {
4581                    rows_for_excerpt.push(next_row);
4582                    rows.next();
4583                } else {
4584                    break;
4585                }
4586            }
4587
4588            let buffer_rows = rows_for_excerpt
4589                .drain(..)
4590                .map(|row| start_buffer_row + row - start_multibuffer_row);
4591            let buffer_indents = region
4592                .buffer
4593                .suggested_indents(buffer_rows, single_indent_size);
4594            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4595                (
4596                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4597                    indent,
4598                )
4599            });
4600            result.extend(multibuffer_indents);
4601        }
4602
4603        result
4604    }
4605
4606    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4607        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4608            let mut size = buffer.indent_size_for_line(range.start.row);
4609            size.len = size
4610                .len
4611                .min(range.end.column)
4612                .saturating_sub(range.start.column);
4613            size
4614        } else {
4615            IndentSize::spaces(0)
4616        }
4617    }
4618
4619    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4620        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4621            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4622        } else {
4623            LineIndent::spaces(0)
4624        }
4625    }
4626
4627    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4628        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4629
4630        if self.language_settings(cx).extend_comment_on_newline {
4631            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4632                let delimiters = language_scope.line_comment_prefixes();
4633                for delimiter in delimiters {
4634                    if *self
4635                        .chars_at(Point::new(row.0, indent.len() as u32))
4636                        .take(delimiter.chars().count())
4637                        .collect::<String>()
4638                        .as_str()
4639                        == **delimiter
4640                    {
4641                        indent.push_str(&delimiter);
4642                        break;
4643                    }
4644                }
4645            }
4646        }
4647
4648        indent
4649    }
4650
4651    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4652    where
4653        T: ToOffset,
4654    {
4655        for char in self.reversed_chars_at(position) {
4656            if !char.is_whitespace() {
4657                return false;
4658            }
4659            if char == '\n' {
4660                return true;
4661            }
4662        }
4663        return true;
4664    }
4665
4666    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4667        while row.0 > 0 {
4668            row.0 -= 1;
4669            if !self.is_line_blank(row) {
4670                return Some(row);
4671            }
4672        }
4673        None
4674    }
4675
4676    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4677        if let Some((_, range)) = self.buffer_line_for_row(row) {
4678            range.end.column - range.start.column
4679        } else {
4680            0
4681        }
4682    }
4683
4684    pub fn buffer_line_for_row(
4685        &self,
4686        row: MultiBufferRow,
4687    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4688        let mut cursor = self.cursor::<Point>();
4689        let point = Point::new(row.0, 0);
4690        cursor.seek(&point);
4691        let region = cursor.region()?;
4692        let overshoot = point.min(region.range.end) - region.range.start;
4693        let buffer_point = region.buffer_range.start + overshoot;
4694        if buffer_point.row > region.buffer_range.end.row {
4695            return None;
4696        }
4697        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4698        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4699            .min(region.buffer_range.end);
4700        Some((region.buffer, line_start..line_end))
4701    }
4702
4703    pub fn max_point(&self) -> Point {
4704        self.text_summary().lines
4705    }
4706
4707    pub fn max_row(&self) -> MultiBufferRow {
4708        MultiBufferRow(self.text_summary().lines.row)
4709    }
4710
4711    pub fn text_summary(&self) -> TextSummary {
4712        self.diff_transforms.summary().output
4713    }
4714
4715    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4716    where
4717        D: TextDimension,
4718        O: ToOffset,
4719    {
4720        let range = range.start.to_offset(self)..range.end.to_offset(self);
4721        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4722        cursor.seek(&range.start, Bias::Right, &());
4723
4724        let Some(first_transform) = cursor.item() else {
4725            return D::from_text_summary(&TextSummary::default());
4726        };
4727
4728        let diff_transform_start = cursor.start().0;
4729        let diff_transform_end = cursor.end(&()).0;
4730        let diff_start = range.start;
4731        let start_overshoot = diff_start - diff_transform_start;
4732        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4733
4734        let mut result = match first_transform {
4735            DiffTransform::BufferContent { .. } => {
4736                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4737                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4738                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4739            }
4740            DiffTransform::DeletedHunk {
4741                buffer_id,
4742                base_text_byte_range,
4743                has_trailing_newline,
4744                ..
4745            } => {
4746                let buffer_start = base_text_byte_range.start + start_overshoot;
4747                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4748                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4749                    panic!("{:?} is in non-existent deleted hunk", range.start)
4750                };
4751
4752                let include_trailing_newline =
4753                    *has_trailing_newline && range.end >= diff_transform_end;
4754                if include_trailing_newline {
4755                    buffer_end -= 1;
4756                }
4757
4758                let mut summary =
4759                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4760
4761                if include_trailing_newline {
4762                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4763                }
4764
4765                summary
4766            }
4767        };
4768        if range.end < diff_transform_end {
4769            return result;
4770        }
4771
4772        cursor.next(&());
4773        result.add_assign(&D::from_text_summary(&cursor.summary(
4774            &range.end,
4775            Bias::Right,
4776            &(),
4777        )));
4778
4779        let Some(last_transform) = cursor.item() else {
4780            return result;
4781        };
4782
4783        let overshoot = range.end - cursor.start().0;
4784        let suffix = match last_transform {
4785            DiffTransform::BufferContent { .. } => {
4786                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4787                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4788            }
4789            DiffTransform::DeletedHunk {
4790                base_text_byte_range,
4791                buffer_id,
4792                has_trailing_newline,
4793                ..
4794            } => {
4795                let buffer_end = base_text_byte_range.start + overshoot;
4796                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4797                    panic!("{:?} is in non-existent deleted hunk", range.end)
4798                };
4799
4800                let mut suffix = base_text
4801                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4802                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4803                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4804                }
4805                suffix
4806            }
4807        };
4808
4809        result.add_assign(&suffix);
4810        result
4811    }
4812
4813    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4814    where
4815        D: TextDimension,
4816    {
4817        // let mut range = range.start..range.end;
4818        let mut summary = D::zero(&());
4819        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4820        cursor.seek(&range.start, Bias::Right, &());
4821        if let Some(excerpt) = cursor.item() {
4822            let mut end_before_newline = cursor.end(&());
4823            if excerpt.has_trailing_newline {
4824                end_before_newline -= ExcerptOffset::new(1);
4825            }
4826
4827            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4828            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4829            let end_in_excerpt =
4830                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4831            summary.add_assign(
4832                &excerpt
4833                    .buffer
4834                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4835            );
4836
4837            if range.end > end_before_newline {
4838                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4839            }
4840
4841            cursor.next(&());
4842        }
4843
4844        if range.end > *cursor.start() {
4845            summary.add_assign(
4846                &cursor
4847                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4848                    .0,
4849            );
4850            if let Some(excerpt) = cursor.item() {
4851                range.end = cmp::max(*cursor.start(), range.end);
4852
4853                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4854                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4855                summary.add_assign(
4856                    &excerpt
4857                        .buffer
4858                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4859                );
4860            }
4861        }
4862
4863        summary
4864    }
4865
4866    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4867    where
4868        D: TextDimension + Ord + Sub<D, Output = D>,
4869    {
4870        self.summaries_for_anchors([anchor])[0]
4871    }
4872
4873    fn resolve_summary_for_anchor<D>(
4874        &self,
4875        anchor: &Anchor,
4876        excerpt_position: D,
4877        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4878    ) -> D
4879    where
4880        D: TextDimension + Ord + Sub<D, Output = D>,
4881    {
4882        loop {
4883            let transform_end_position = diff_transforms.end(&()).0.0;
4884            let at_transform_end =
4885                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4886            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4887                diff_transforms.next(&());
4888                continue;
4889            }
4890
4891            let mut position = diff_transforms.start().1.0;
4892            match diff_transforms.item() {
4893                Some(DiffTransform::DeletedHunk {
4894                    buffer_id,
4895                    base_text_byte_range,
4896                    ..
4897                }) => {
4898                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4899                        if let Some(base_text) =
4900                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4901                        {
4902                            if base_text.can_resolve(&diff_base_anchor) {
4903                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4904                                if base_text_offset >= base_text_byte_range.start
4905                                    && base_text_offset <= base_text_byte_range.end
4906                                {
4907                                    let position_in_hunk = base_text
4908                                        .text_summary_for_range::<D, _>(
4909                                            base_text_byte_range.start..base_text_offset,
4910                                        );
4911                                    position.add_assign(&position_in_hunk);
4912                                } else if at_transform_end {
4913                                    diff_transforms.next(&());
4914                                    continue;
4915                                }
4916                            }
4917                        }
4918                    }
4919                }
4920                _ => {
4921                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4922                        diff_transforms.next(&());
4923                        continue;
4924                    }
4925                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4926                    position.add_assign(&overshoot);
4927                }
4928            }
4929
4930            return position;
4931        }
4932    }
4933
4934    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4935        let mut cursor = self
4936            .excerpts
4937            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4938        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4939
4940        cursor.seek(&Some(locator), Bias::Left, &());
4941        if cursor.item().is_none() {
4942            cursor.next(&());
4943        }
4944
4945        let mut position = cursor.start().1;
4946        if let Some(excerpt) = cursor.item() {
4947            if excerpt.id == anchor.excerpt_id {
4948                let excerpt_buffer_start = excerpt
4949                    .buffer
4950                    .offset_for_anchor(&excerpt.range.context.start);
4951                let excerpt_buffer_end =
4952                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4953                let buffer_position = cmp::min(
4954                    excerpt_buffer_end,
4955                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4956                );
4957                if buffer_position > excerpt_buffer_start {
4958                    position.value += buffer_position - excerpt_buffer_start;
4959                }
4960            }
4961        }
4962        position
4963    }
4964
4965    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4966        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4967            excerpt_id = *replacement;
4968        }
4969        return excerpt_id;
4970    }
4971
4972    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4973    where
4974        D: TextDimension + Ord + Sub<D, Output = D>,
4975        I: 'a + IntoIterator<Item = &'a Anchor>,
4976    {
4977        let mut anchors = anchors.into_iter().peekable();
4978        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4979        let mut diff_transforms_cursor = self
4980            .diff_transforms
4981            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4982        diff_transforms_cursor.next(&());
4983
4984        let mut summaries = Vec::new();
4985        while let Some(anchor) = anchors.peek() {
4986            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4987            let excerpt_anchors = iter::from_fn(|| {
4988                let anchor = anchors.peek()?;
4989                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4990                    Some(anchors.next().unwrap())
4991                } else {
4992                    None
4993                }
4994            });
4995
4996            let locator = self.excerpt_locator_for_id(excerpt_id);
4997            cursor.seek_forward(locator, Bias::Left, &());
4998            if cursor.item().is_none() {
4999                cursor.next(&());
5000            }
5001
5002            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
5003            if let Some(excerpt) = cursor.item() {
5004                if excerpt.id != excerpt_id {
5005                    let position = self.resolve_summary_for_anchor(
5006                        &Anchor::min(),
5007                        excerpt_start_position,
5008                        &mut diff_transforms_cursor,
5009                    );
5010                    summaries.extend(excerpt_anchors.map(|_| position));
5011                    continue;
5012                }
5013                let excerpt_buffer_start =
5014                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
5015                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
5016                for (buffer_summary, anchor) in excerpt
5017                    .buffer
5018                    .summaries_for_anchors_with_payload::<D, _, _>(
5019                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5020                    )
5021                {
5022                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5023                    let mut position = excerpt_start_position;
5024                    if summary > excerpt_buffer_start {
5025                        position.add_assign(&(summary - excerpt_buffer_start));
5026                    }
5027
5028                    if position > diff_transforms_cursor.start().0.0 {
5029                        diff_transforms_cursor.seek_forward(
5030                            &ExcerptDimension(position),
5031                            Bias::Left,
5032                            &(),
5033                        );
5034                    }
5035
5036                    summaries.push(self.resolve_summary_for_anchor(
5037                        anchor,
5038                        position,
5039                        &mut diff_transforms_cursor,
5040                    ));
5041                }
5042            } else {
5043                diff_transforms_cursor.seek_forward(
5044                    &ExcerptDimension(excerpt_start_position),
5045                    Bias::Left,
5046                    &(),
5047                );
5048                let position = self.resolve_summary_for_anchor(
5049                    &Anchor::max(),
5050                    excerpt_start_position,
5051                    &mut diff_transforms_cursor,
5052                );
5053                summaries.extend(excerpt_anchors.map(|_| position));
5054            }
5055        }
5056
5057        summaries
5058    }
5059
5060    pub fn dimensions_from_points<'a, D>(
5061        &'a self,
5062        points: impl 'a + IntoIterator<Item = Point>,
5063    ) -> impl 'a + Iterator<Item = D>
5064    where
5065        D: TextDimension + Sub<D, Output = D>,
5066    {
5067        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
5068        cursor.seek(&DimensionPair {
5069            key: Point::default(),
5070            value: None,
5071        });
5072        let mut points = points.into_iter();
5073        iter::from_fn(move || {
5074            let point = points.next()?;
5075
5076            cursor.seek_forward(&DimensionPair {
5077                key: point,
5078                value: None,
5079            });
5080
5081            if let Some(region) = cursor.region() {
5082                let overshoot = point - region.range.start.key;
5083                let buffer_point = region.buffer_range.start.key + overshoot;
5084                let mut position = region.range.start.value.unwrap();
5085                position.add_assign(
5086                    &region
5087                        .buffer
5088                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
5089                );
5090                if point == region.range.end.key && region.has_trailing_newline {
5091                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
5092                }
5093                return Some(position);
5094            } else {
5095                return Some(D::from_text_summary(&self.text_summary()));
5096            }
5097        })
5098    }
5099
5100    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5101    where
5102        I: 'a + IntoIterator<Item = &'a Anchor>,
5103    {
5104        let mut anchors = anchors.into_iter().enumerate().peekable();
5105        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5106        cursor.next(&());
5107
5108        let mut result = Vec::new();
5109
5110        while let Some((_, anchor)) = anchors.peek() {
5111            let old_excerpt_id = anchor.excerpt_id;
5112
5113            // Find the location where this anchor's excerpt should be.
5114            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5115            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
5116
5117            if cursor.item().is_none() {
5118                cursor.next(&());
5119            }
5120
5121            let next_excerpt = cursor.item();
5122            let prev_excerpt = cursor.prev_item();
5123
5124            // Process all of the anchors for this excerpt.
5125            while let Some((_, anchor)) = anchors.peek() {
5126                if anchor.excerpt_id != old_excerpt_id {
5127                    break;
5128                }
5129                let (anchor_ix, anchor) = anchors.next().unwrap();
5130                let mut anchor = *anchor;
5131
5132                // Leave min and max anchors unchanged if invalid or
5133                // if the old excerpt still exists at this location
5134                let mut kept_position = next_excerpt
5135                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
5136                    || old_excerpt_id == ExcerptId::max()
5137                    || old_excerpt_id == ExcerptId::min();
5138
5139                // If the old excerpt no longer exists at this location, then attempt to
5140                // find an equivalent position for this anchor in an adjacent excerpt.
5141                if !kept_position {
5142                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5143                        if excerpt.contains(&anchor) {
5144                            anchor.excerpt_id = excerpt.id;
5145                            kept_position = true;
5146                            break;
5147                        }
5148                    }
5149                }
5150
5151                // If there's no adjacent excerpt that contains the anchor's position,
5152                // then report that the anchor has lost its position.
5153                if !kept_position {
5154                    anchor = if let Some(excerpt) = next_excerpt {
5155                        let mut text_anchor = excerpt
5156                            .range
5157                            .context
5158                            .start
5159                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5160                        if text_anchor
5161                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5162                            .is_gt()
5163                        {
5164                            text_anchor = excerpt.range.context.end;
5165                        }
5166                        Anchor {
5167                            buffer_id: Some(excerpt.buffer_id),
5168                            excerpt_id: excerpt.id,
5169                            text_anchor,
5170                            diff_base_anchor: None,
5171                        }
5172                    } else if let Some(excerpt) = prev_excerpt {
5173                        let mut text_anchor = excerpt
5174                            .range
5175                            .context
5176                            .end
5177                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5178                        if text_anchor
5179                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5180                            .is_lt()
5181                        {
5182                            text_anchor = excerpt.range.context.start;
5183                        }
5184                        Anchor {
5185                            buffer_id: Some(excerpt.buffer_id),
5186                            excerpt_id: excerpt.id,
5187                            text_anchor,
5188                            diff_base_anchor: None,
5189                        }
5190                    } else if anchor.text_anchor.bias == Bias::Left {
5191                        Anchor::min()
5192                    } else {
5193                        Anchor::max()
5194                    };
5195                }
5196
5197                result.push((anchor_ix, anchor, kept_position));
5198            }
5199        }
5200        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5201        result
5202    }
5203
5204    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5205        self.anchor_at(position, Bias::Left)
5206    }
5207
5208    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5209        self.anchor_at(position, Bias::Right)
5210    }
5211
5212    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5213        let offset = position.to_offset(self);
5214
5215        // Find the given position in the diff transforms. Determine the corresponding
5216        // offset in the excerpts, and whether the position is within a deleted hunk.
5217        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
5218        diff_transforms.seek(&offset, Bias::Right, &());
5219
5220        if offset == diff_transforms.start().0 && bias == Bias::Left {
5221            if let Some(prev_item) = diff_transforms.prev_item() {
5222                match prev_item {
5223                    DiffTransform::DeletedHunk { .. } => {
5224                        diff_transforms.prev(&());
5225                    }
5226                    _ => {}
5227                }
5228            }
5229        }
5230        let offset_in_transform = offset - diff_transforms.start().0;
5231        let mut excerpt_offset = diff_transforms.start().1;
5232        let mut diff_base_anchor = None;
5233        if let Some(DiffTransform::DeletedHunk {
5234            buffer_id,
5235            base_text_byte_range,
5236            has_trailing_newline,
5237            ..
5238        }) = diff_transforms.item()
5239        {
5240            let diff = self.diffs.get(buffer_id).expect("missing diff");
5241            if offset_in_transform > base_text_byte_range.len() {
5242                debug_assert!(*has_trailing_newline);
5243                bias = Bias::Right;
5244            } else {
5245                diff_base_anchor = Some(
5246                    diff.base_text()
5247                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5248                );
5249                bias = Bias::Left;
5250            }
5251        } else {
5252            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5253        };
5254
5255        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5256            return Anchor {
5257                buffer_id: Some(buffer_id),
5258                excerpt_id: *excerpt_id,
5259                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5260                diff_base_anchor,
5261            };
5262        }
5263
5264        let mut excerpts = self
5265            .excerpts
5266            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5267        excerpts.seek(&excerpt_offset, Bias::Right, &());
5268        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5269            excerpts.prev(&());
5270        }
5271        if let Some(excerpt) = excerpts.item() {
5272            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5273            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5274                overshoot -= 1;
5275                bias = Bias::Right;
5276            }
5277
5278            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5279            let text_anchor =
5280                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5281            Anchor {
5282                buffer_id: Some(excerpt.buffer_id),
5283                excerpt_id: excerpt.id,
5284                text_anchor,
5285                diff_base_anchor,
5286            }
5287        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5288            Anchor::min()
5289        } else {
5290            Anchor::max()
5291        }
5292    }
5293
5294    /// Returns an anchor for the given excerpt and text anchor,
5295    /// returns None if the excerpt_id is no longer valid.
5296    pub fn anchor_in_excerpt(
5297        &self,
5298        excerpt_id: ExcerptId,
5299        text_anchor: text::Anchor,
5300    ) -> Option<Anchor> {
5301        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5302        let locator = self.excerpt_locator_for_id(excerpt_id);
5303        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5304        cursor.seek(locator, Bias::Left, &());
5305        if let Some(excerpt) = cursor.item() {
5306            if excerpt.id == excerpt_id {
5307                let text_anchor = excerpt.clip_anchor(text_anchor);
5308                drop(cursor);
5309                return Some(Anchor {
5310                    buffer_id: Some(excerpt.buffer_id),
5311                    excerpt_id,
5312                    text_anchor,
5313                    diff_base_anchor: None,
5314                });
5315            }
5316        }
5317        None
5318    }
5319
5320    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5321        Some(self.excerpt(excerpt_id)?.range.context.clone())
5322    }
5323
5324    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5325        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5326            true
5327        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5328            excerpt.buffer.can_resolve(&anchor.text_anchor)
5329        } else {
5330            false
5331        }
5332    }
5333
5334    pub fn excerpts(
5335        &self,
5336    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5337        self.excerpts
5338            .iter()
5339            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5340    }
5341
5342    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
5343        let excerpts = self.excerpts.cursor(&());
5344        let diff_transforms = self.diff_transforms.cursor(&());
5345        MultiBufferCursor {
5346            excerpts,
5347            diff_transforms,
5348            diffs: &self.diffs,
5349            cached_region: None,
5350        }
5351    }
5352
5353    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5354        let start_locator = self.excerpt_locator_for_id(id);
5355        let mut excerpts = self
5356            .excerpts
5357            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5358        excerpts.seek(&Some(start_locator), Bias::Left, &());
5359        excerpts.prev(&());
5360
5361        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(&());
5362        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5363        if diff_transforms.end(&()).excerpt_dimension < excerpts.start().1 {
5364            diff_transforms.next(&());
5365        }
5366
5367        let excerpt = excerpts.item()?;
5368        Some(MultiBufferExcerpt {
5369            excerpt,
5370            offset: diff_transforms.start().output_dimension.0,
5371            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5372            excerpt_offset: excerpts.start().1.clone(),
5373            diff_transforms,
5374        })
5375    }
5376
5377    pub fn excerpt_boundaries_in_range<R, T>(
5378        &self,
5379        range: R,
5380    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5381    where
5382        R: RangeBounds<T>,
5383        T: ToOffset,
5384    {
5385        let start_offset;
5386        let start = match range.start_bound() {
5387            Bound::Included(start) => {
5388                start_offset = start.to_offset(self);
5389                Bound::Included(start_offset)
5390            }
5391            Bound::Excluded(_) => {
5392                panic!("not supported")
5393            }
5394            Bound::Unbounded => {
5395                start_offset = 0;
5396                Bound::Unbounded
5397            }
5398        };
5399        let end = match range.end_bound() {
5400            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5401            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5402            Bound::Unbounded => Bound::Unbounded,
5403        };
5404        let bounds = (start, end);
5405
5406        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5407        cursor.seek(&DimensionPair {
5408            key: start_offset,
5409            value: None,
5410        });
5411
5412        if cursor
5413            .region()
5414            .is_some_and(|region| bounds.contains(&region.range.start.key))
5415        {
5416            cursor.prev_excerpt();
5417        } else {
5418            cursor.seek_to_start_of_current_excerpt();
5419        }
5420        let mut prev_region = cursor.region();
5421
5422        cursor.next_excerpt();
5423
5424        iter::from_fn(move || {
5425            loop {
5426                if self.singleton {
5427                    return None;
5428                }
5429
5430                let next_region = cursor.region()?;
5431                cursor.next_excerpt();
5432                if !bounds.contains(&next_region.range.start.key) {
5433                    prev_region = Some(next_region);
5434                    continue;
5435                }
5436
5437                let next_region_start = next_region.range.start.value.unwrap();
5438                let next_region_end = if let Some(region) = cursor.region() {
5439                    region.range.start.value.unwrap()
5440                } else {
5441                    self.max_point()
5442                };
5443
5444                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5445                    id: region.excerpt.id,
5446                    buffer: region.excerpt.buffer.clone(),
5447                    buffer_id: region.excerpt.buffer_id,
5448                    range: region.excerpt.range.clone(),
5449                    end_row: MultiBufferRow(next_region_start.row),
5450                });
5451
5452                let next = ExcerptInfo {
5453                    id: next_region.excerpt.id,
5454                    buffer: next_region.excerpt.buffer.clone(),
5455                    buffer_id: next_region.excerpt.buffer_id,
5456                    range: next_region.excerpt.range.clone(),
5457                    end_row: if next_region.excerpt.has_trailing_newline {
5458                        MultiBufferRow(next_region_end.row - 1)
5459                    } else {
5460                        MultiBufferRow(next_region_end.row)
5461                    },
5462                };
5463
5464                let row = MultiBufferRow(next_region_start.row);
5465
5466                prev_region = Some(next_region);
5467
5468                return Some(ExcerptBoundary { row, prev, next });
5469            }
5470        })
5471    }
5472
5473    pub fn edit_count(&self) -> usize {
5474        self.edit_count
5475    }
5476
5477    pub fn non_text_state_update_count(&self) -> usize {
5478        self.non_text_state_update_count
5479    }
5480
5481    /// Returns the smallest enclosing bracket ranges containing the given range or
5482    /// None if no brackets contain range or the range is not contained in a single
5483    /// excerpt
5484    ///
5485    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5486    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5487        &self,
5488        range: Range<T>,
5489        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5490    ) -> Option<(Range<usize>, Range<usize>)> {
5491        let range = range.start.to_offset(self)..range.end.to_offset(self);
5492        let mut excerpt = self.excerpt_containing(range.clone())?;
5493        let buffer = excerpt.buffer();
5494        let excerpt_buffer_range = excerpt.buffer_range();
5495
5496        // Filter to ranges contained in the excerpt
5497        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5498            excerpt_buffer_range.contains(&open.start)
5499                && excerpt_buffer_range.contains(&close.end)
5500                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5501        };
5502
5503        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5504            excerpt.map_range_to_buffer(range),
5505            Some(&range_filter),
5506        )?;
5507
5508        Some((
5509            excerpt.map_range_from_buffer(open),
5510            excerpt.map_range_from_buffer(close),
5511        ))
5512    }
5513
5514    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5515    /// not contained in a single excerpt
5516    pub fn enclosing_bracket_ranges<T: ToOffset>(
5517        &self,
5518        range: Range<T>,
5519    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5520        let range = range.start.to_offset(self)..range.end.to_offset(self);
5521        let mut excerpt = self.excerpt_containing(range.clone())?;
5522
5523        Some(
5524            excerpt
5525                .buffer()
5526                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5527                .filter_map(move |pair| {
5528                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5529                        Some((
5530                            excerpt.map_range_from_buffer(pair.open_range),
5531                            excerpt.map_range_from_buffer(pair.close_range),
5532                        ))
5533                    } else {
5534                        None
5535                    }
5536                }),
5537        )
5538    }
5539
5540    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5541    /// not contained in a single excerpt
5542    pub fn text_object_ranges<T: ToOffset>(
5543        &self,
5544        range: Range<T>,
5545        options: TreeSitterOptions,
5546    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5547        let range = range.start.to_offset(self)..range.end.to_offset(self);
5548        self.excerpt_containing(range.clone())
5549            .map(|mut excerpt| {
5550                excerpt
5551                    .buffer()
5552                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5553                    .filter_map(move |(range, text_object)| {
5554                        if excerpt.contains_buffer_range(range.clone()) {
5555                            Some((excerpt.map_range_from_buffer(range), text_object))
5556                        } else {
5557                            None
5558                        }
5559                    })
5560            })
5561            .into_iter()
5562            .flatten()
5563    }
5564
5565    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5566    /// not contained in a single excerpt
5567    pub fn bracket_ranges<T: ToOffset>(
5568        &self,
5569        range: Range<T>,
5570    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5571        let range = range.start.to_offset(self)..range.end.to_offset(self);
5572        let mut excerpt = self.excerpt_containing(range.clone())?;
5573
5574        Some(
5575            excerpt
5576                .buffer()
5577                .bracket_ranges(excerpt.map_range_to_buffer(range))
5578                .filter_map(move |pair| {
5579                    let buffer_range = pair.open_range.start..pair.close_range.end;
5580                    if excerpt.contains_buffer_range(buffer_range) {
5581                        Some((
5582                            excerpt.map_range_from_buffer(pair.open_range),
5583                            excerpt.map_range_from_buffer(pair.close_range),
5584                        ))
5585                    } else {
5586                        None
5587                    }
5588                }),
5589        )
5590    }
5591
5592    pub fn redacted_ranges<'a, T: ToOffset>(
5593        &'a self,
5594        range: Range<T>,
5595        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5596    ) -> impl Iterator<Item = Range<usize>> + 'a {
5597        let range = range.start.to_offset(self)..range.end.to_offset(self);
5598        self.lift_buffer_metadata(range, move |buffer, range| {
5599            if redaction_enabled(buffer.file()) {
5600                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5601            } else {
5602                None
5603            }
5604        })
5605        .map(|(range, _, _)| range)
5606    }
5607
5608    pub fn runnable_ranges(
5609        &self,
5610        range: Range<Anchor>,
5611    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5612        let range = range.start.to_offset(self)..range.end.to_offset(self);
5613        self.lift_buffer_metadata(range, move |buffer, range| {
5614            Some(
5615                buffer
5616                    .runnable_ranges(range.clone())
5617                    .filter(move |runnable| {
5618                        runnable.run_range.start >= range.start
5619                            && runnable.run_range.end < range.end
5620                    })
5621                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5622            )
5623        })
5624        .map(|(run_range, runnable, _)| language::RunnableRange {
5625            run_range,
5626            ..runnable
5627        })
5628    }
5629
5630    pub fn line_indents(
5631        &self,
5632        start_row: MultiBufferRow,
5633        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5634    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5635        let max_point = self.max_point();
5636        let mut cursor = self.cursor::<Point>();
5637        cursor.seek(&Point::new(start_row.0, 0));
5638        iter::from_fn(move || {
5639            let mut region = cursor.region()?;
5640            while !buffer_filter(&region.excerpt.buffer) {
5641                cursor.next();
5642                region = cursor.region()?;
5643            }
5644            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5645            let buffer_start_row =
5646                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5647
5648            let buffer_end_row = if region.is_main_buffer
5649                && (region.has_trailing_newline || region.range.end == max_point)
5650            {
5651                region.buffer_range.end.row
5652            } else {
5653                region.buffer_range.end.row.saturating_sub(1)
5654            };
5655
5656            let line_indents = region
5657                .buffer
5658                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5659            cursor.next();
5660            return Some(line_indents.map(move |(buffer_row, indent)| {
5661                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5662                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5663            }));
5664        })
5665        .flatten()
5666    }
5667
5668    pub fn reversed_line_indents(
5669        &self,
5670        end_row: MultiBufferRow,
5671        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5672    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5673        let max_point = self.max_point();
5674        let mut cursor = self.cursor::<Point>();
5675        cursor.seek(&Point::new(end_row.0, 0));
5676        iter::from_fn(move || {
5677            let mut region = cursor.region()?;
5678            while !buffer_filter(&region.excerpt.buffer) {
5679                cursor.prev();
5680                region = cursor.region()?;
5681            }
5682
5683            let buffer_start_row = region.buffer_range.start.row;
5684            let buffer_end_row = if region.is_main_buffer
5685                && (region.has_trailing_newline || region.range.end == max_point)
5686            {
5687                region.buffer_range.end.row + 1
5688            } else {
5689                region.buffer_range.end.row
5690            };
5691
5692            let overshoot = end_row.0 - region.range.start.row;
5693            let buffer_end_row =
5694                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5695
5696            let line_indents = region
5697                .buffer
5698                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5699            cursor.prev();
5700            return Some(line_indents.map(move |(buffer_row, indent)| {
5701                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5702                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5703            }));
5704        })
5705        .flatten()
5706    }
5707
5708    pub async fn enclosing_indent(
5709        &self,
5710        mut target_row: MultiBufferRow,
5711    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5712        let max_row = MultiBufferRow(self.max_point().row);
5713        if target_row >= max_row {
5714            return None;
5715        }
5716
5717        let mut target_indent = self.line_indent_for_row(target_row);
5718
5719        // If the current row is at the start of an indented block, we want to return this
5720        // block as the enclosing indent.
5721        if !target_indent.is_line_empty() && target_row < max_row {
5722            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5723            if !next_line_indent.is_line_empty()
5724                && target_indent.raw_len() < next_line_indent.raw_len()
5725            {
5726                target_indent = next_line_indent;
5727                target_row.0 += 1;
5728            }
5729        }
5730
5731        const SEARCH_ROW_LIMIT: u32 = 25000;
5732        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5733        const YIELD_INTERVAL: u32 = 100;
5734
5735        let mut accessed_row_counter = 0;
5736
5737        // If there is a blank line at the current row, search for the next non indented lines
5738        if target_indent.is_line_empty() {
5739            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5740            let end =
5741                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5742
5743            let mut non_empty_line_above = None;
5744            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5745                if row < start {
5746                    break;
5747                }
5748                accessed_row_counter += 1;
5749                if accessed_row_counter == YIELD_INTERVAL {
5750                    accessed_row_counter = 0;
5751                    yield_now().await;
5752                }
5753                if !indent.is_line_empty() {
5754                    non_empty_line_above = Some((row, indent));
5755                    break;
5756                }
5757            }
5758
5759            let mut non_empty_line_below = None;
5760            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5761                if row > end {
5762                    break;
5763                }
5764                accessed_row_counter += 1;
5765                if accessed_row_counter == YIELD_INTERVAL {
5766                    accessed_row_counter = 0;
5767                    yield_now().await;
5768                }
5769                if !indent.is_line_empty() {
5770                    non_empty_line_below = Some((row, indent));
5771                    break;
5772                }
5773            }
5774
5775            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5776                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5777                    if above_indent.raw_len() >= below_indent.raw_len() {
5778                        (above_row, above_indent)
5779                    } else {
5780                        (below_row, below_indent)
5781                    }
5782                }
5783                (Some(above), None) => above,
5784                (None, Some(below)) => below,
5785                _ => return None,
5786            };
5787
5788            target_indent = indent;
5789            target_row = row;
5790        }
5791
5792        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5793        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5794
5795        let mut start_indent = None;
5796        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5797            if row < start {
5798                break;
5799            }
5800            accessed_row_counter += 1;
5801            if accessed_row_counter == YIELD_INTERVAL {
5802                accessed_row_counter = 0;
5803                yield_now().await;
5804            }
5805            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5806                start_indent = Some((row, indent));
5807                break;
5808            }
5809        }
5810        let (start_row, start_indent_size) = start_indent?;
5811
5812        let mut end_indent = (end, None);
5813        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5814            if row > end {
5815                break;
5816            }
5817            accessed_row_counter += 1;
5818            if accessed_row_counter == YIELD_INTERVAL {
5819                accessed_row_counter = 0;
5820                yield_now().await;
5821            }
5822            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5823                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5824                break;
5825            }
5826        }
5827        let (end_row, end_indent_size) = end_indent;
5828
5829        let indent = if let Some(end_indent_size) = end_indent_size {
5830            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5831                start_indent_size
5832            } else {
5833                end_indent_size
5834            }
5835        } else {
5836            start_indent_size
5837        };
5838
5839        Some((start_row..end_row, indent))
5840    }
5841
5842    pub fn indent_guides_in_range<T: ToPoint>(
5843        &self,
5844        range: Range<T>,
5845        ignore_disabled_for_language: bool,
5846        cx: &App,
5847    ) -> impl Iterator<Item = IndentGuide> {
5848        let range = range.start.to_point(self)..range.end.to_point(self);
5849        let start_row = MultiBufferRow(range.start.row);
5850        let end_row = MultiBufferRow(range.end.row);
5851
5852        let mut row_indents = self.line_indents(start_row, |buffer| {
5853            let settings =
5854                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5855            settings.indent_guides.enabled || ignore_disabled_for_language
5856        });
5857
5858        let mut result = Vec::new();
5859        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5860
5861        let mut prev_settings = None;
5862        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5863            if first_row > end_row {
5864                break;
5865            }
5866            let current_depth = indent_stack.len() as u32;
5867
5868            // Avoid retrieving the language settings repeatedly for every buffer row.
5869            if let Some((prev_buffer_id, _)) = &prev_settings {
5870                if prev_buffer_id != &buffer.remote_id() {
5871                    prev_settings.take();
5872                }
5873            }
5874            let settings = &prev_settings
5875                .get_or_insert_with(|| {
5876                    (
5877                        buffer.remote_id(),
5878                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5879                    )
5880                })
5881                .1;
5882            let tab_size = settings.tab_size.get();
5883
5884            // When encountering empty, continue until found useful line indent
5885            // then add to the indent stack with the depth found
5886            let mut found_indent = false;
5887            let mut last_row = first_row;
5888            if line_indent.is_line_blank() {
5889                while !found_indent {
5890                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5891                        break;
5892                    };
5893                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5894                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5895                        break;
5896                    }
5897
5898                    if new_line_indent.is_line_blank() {
5899                        continue;
5900                    }
5901                    last_row = target_row.min(end_row);
5902                    line_indent = new_line_indent;
5903                    found_indent = true;
5904                    break;
5905                }
5906            } else {
5907                found_indent = true
5908            }
5909
5910            let depth = if found_indent {
5911                line_indent.len(tab_size) / tab_size
5912                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5913            } else {
5914                0
5915            };
5916
5917            match depth.cmp(&current_depth) {
5918                cmp::Ordering::Less => {
5919                    for _ in 0..(current_depth - depth) {
5920                        let mut indent = indent_stack.pop().unwrap();
5921                        if last_row != first_row {
5922                            // In this case, we landed on an empty row, had to seek forward,
5923                            // and discovered that the indent we where on is ending.
5924                            // This means that the last display row must
5925                            // be on line that ends this indent range, so we
5926                            // should display the range up to the first non-empty line
5927                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5928                        }
5929
5930                        result.push(indent)
5931                    }
5932                }
5933                cmp::Ordering::Greater => {
5934                    for next_depth in current_depth..depth {
5935                        indent_stack.push(IndentGuide {
5936                            buffer_id: buffer.remote_id(),
5937                            start_row: first_row,
5938                            end_row: last_row,
5939                            depth: next_depth,
5940                            tab_size,
5941                            settings: settings.indent_guides,
5942                        });
5943                    }
5944                }
5945                _ => {}
5946            }
5947
5948            for indent in indent_stack.iter_mut() {
5949                indent.end_row = last_row;
5950            }
5951        }
5952
5953        result.extend(indent_stack);
5954        result.into_iter()
5955    }
5956
5957    pub fn trailing_excerpt_update_count(&self) -> usize {
5958        self.trailing_excerpt_update_count
5959    }
5960
5961    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5962        self.point_to_buffer_offset(point)
5963            .and_then(|(buffer, _)| buffer.file())
5964    }
5965
5966    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5967        self.point_to_buffer_offset(point)
5968            .and_then(|(buffer, offset)| buffer.language_at(offset))
5969    }
5970
5971    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5972        self.excerpts
5973            .first()
5974            .map(|excerpt| &excerpt.buffer)
5975            .map(|buffer| {
5976                language_settings(
5977                    buffer.language().map(|language| language.name()),
5978                    buffer.file(),
5979                    cx,
5980                )
5981            })
5982            .unwrap_or_else(move || self.language_settings_at(0, cx))
5983    }
5984
5985    pub fn language_settings_at<'a, T: ToOffset>(
5986        &'a self,
5987        point: T,
5988        cx: &'a App,
5989    ) -> Cow<'a, LanguageSettings> {
5990        let mut language = None;
5991        let mut file = None;
5992        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5993            language = buffer.language_at(offset);
5994            file = buffer.file();
5995        }
5996        language_settings(language.map(|l| l.name()), file, cx)
5997    }
5998
5999    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6000        self.point_to_buffer_offset(point)
6001            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6002    }
6003
6004    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6005        self.point_to_buffer_offset(point)
6006            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6007            .unwrap_or_default()
6008    }
6009
6010    pub fn language_indent_size_at<T: ToOffset>(
6011        &self,
6012        position: T,
6013        cx: &App,
6014    ) -> Option<IndentSize> {
6015        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6016        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6017    }
6018
6019    pub fn is_dirty(&self) -> bool {
6020        self.is_dirty
6021    }
6022
6023    pub fn has_deleted_file(&self) -> bool {
6024        self.has_deleted_file
6025    }
6026
6027    pub fn has_conflict(&self) -> bool {
6028        self.has_conflict
6029    }
6030
6031    pub fn has_diagnostics(&self) -> bool {
6032        self.excerpts
6033            .iter()
6034            .any(|excerpt| excerpt.buffer.has_diagnostics())
6035    }
6036
6037    pub fn diagnostic_group(
6038        &self,
6039        buffer_id: BufferId,
6040        group_id: usize,
6041    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
6042        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
6043            if buffer.remote_id() != buffer_id {
6044                return None;
6045            };
6046            Some(
6047                buffer
6048                    .diagnostics_in_range(range, false)
6049                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6050                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
6051            )
6052        })
6053        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6054    }
6055
6056    pub fn diagnostics_in_range<'a, T>(
6057        &'a self,
6058        range: Range<T>,
6059    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
6060    where
6061        T: 'a
6062            + text::ToOffset
6063            + text::FromAnchor
6064            + TextDimension
6065            + Ord
6066            + Sub<T, Output = T>
6067            + fmt::Debug,
6068    {
6069        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6070            Some(
6071                buffer
6072                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6073                    .map(|entry| (entry.range, entry.diagnostic)),
6074            )
6075        })
6076        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6077    }
6078
6079    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
6080        &'a self,
6081        range: Range<T>,
6082    ) -> impl Iterator<Item = (BufferId, DiagnosticEntry<T>)> + 'a
6083    where
6084        T: 'a
6085            + text::ToOffset
6086            + text::FromAnchor
6087            + TextDimension
6088            + Ord
6089            + Sub<T, Output = T>
6090            + fmt::Debug,
6091    {
6092        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6093            Some(
6094                buffer
6095                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6096                    .map(|entry| (entry.range, entry.diagnostic)),
6097            )
6098        })
6099        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntry { diagnostic, range }))
6100    }
6101
6102    pub fn syntax_ancestor<T: ToOffset>(
6103        &self,
6104        range: Range<T>,
6105    ) -> Option<(tree_sitter::Node<'_>, MultiOrSingleBufferOffsetRange)> {
6106        let range = range.start.to_offset(self)..range.end.to_offset(self);
6107        let mut excerpt = self.excerpt_containing(range.clone())?;
6108        let node = excerpt
6109            .buffer()
6110            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6111        let node_range = node.byte_range();
6112        let range = if excerpt.contains_buffer_range(node_range.clone()) {
6113            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
6114        } else {
6115            MultiOrSingleBufferOffsetRange::Single(node_range)
6116        };
6117        Some((node, range))
6118    }
6119
6120    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6121        let (excerpt_id, _, buffer) = self.as_singleton()?;
6122        let outline = buffer.outline(theme)?;
6123        Some(Outline::new(
6124            outline
6125                .items
6126                .into_iter()
6127                .flat_map(|item| {
6128                    Some(OutlineItem {
6129                        depth: item.depth,
6130                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
6131                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
6132                        text: item.text,
6133                        highlight_ranges: item.highlight_ranges,
6134                        name_ranges: item.name_ranges,
6135                        body_range: item.body_range.and_then(|body_range| {
6136                            Some(
6137                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
6138                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
6139                            )
6140                        }),
6141                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6142                            Some(
6143                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6144                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6145                            )
6146                        }),
6147                    })
6148                })
6149                .collect(),
6150        ))
6151    }
6152
6153    pub fn symbols_containing<T: ToOffset>(
6154        &self,
6155        offset: T,
6156        theme: Option<&SyntaxTheme>,
6157    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6158        let anchor = self.anchor_before(offset);
6159        let excerpt_id = anchor.excerpt_id;
6160        let excerpt = self.excerpt(excerpt_id)?;
6161        Some((
6162            excerpt.buffer_id,
6163            excerpt
6164                .buffer
6165                .symbols_containing(anchor.text_anchor, theme)
6166                .into_iter()
6167                .flatten()
6168                .flat_map(|item| {
6169                    Some(OutlineItem {
6170                        depth: item.depth,
6171                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6172                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6173                        text: item.text,
6174                        highlight_ranges: item.highlight_ranges,
6175                        name_ranges: item.name_ranges,
6176                        body_range: item.body_range.and_then(|body_range| {
6177                            Some(
6178                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6179                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6180                            )
6181                        }),
6182                        annotation_range: item.annotation_range.and_then(|body_range| {
6183                            Some(
6184                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6185                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6186                            )
6187                        }),
6188                    })
6189                })
6190                .collect(),
6191        ))
6192    }
6193
6194    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6195        if id == ExcerptId::min() {
6196            Locator::min_ref()
6197        } else if id == ExcerptId::max() {
6198            Locator::max_ref()
6199        } else {
6200            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6201            cursor.seek(&id, Bias::Left, &());
6202            if let Some(entry) = cursor.item() {
6203                if entry.id == id {
6204                    return &entry.locator;
6205                }
6206            }
6207            panic!("invalid excerpt id {id:?}")
6208        }
6209    }
6210
6211    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6212    fn excerpt_locators_for_ids(
6213        &self,
6214        ids: impl IntoIterator<Item = ExcerptId>,
6215    ) -> SmallVec<[Locator; 1]> {
6216        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6217        sorted_ids.sort_unstable();
6218        let mut locators = SmallVec::new();
6219
6220        while sorted_ids.last() == Some(&ExcerptId::max()) {
6221            sorted_ids.pop();
6222            if let Some(mapping) = self.excerpt_ids.last() {
6223                locators.push(mapping.locator.clone());
6224            }
6225        }
6226
6227        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6228        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6229            sorted_ids.next();
6230            if let Some(mapping) = self.excerpt_ids.first() {
6231                locators.push(mapping.locator.clone());
6232            }
6233        }
6234
6235        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6236        for id in sorted_ids {
6237            if cursor.seek_forward(&id, Bias::Left, &()) {
6238                locators.push(cursor.item().unwrap().locator.clone());
6239            } else {
6240                panic!("invalid excerpt id {:?}", id);
6241            }
6242        }
6243
6244        locators.sort_unstable();
6245        locators
6246    }
6247
6248    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6249        Some(self.excerpt(excerpt_id)?.buffer_id)
6250    }
6251
6252    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6253        Some(&self.excerpt(excerpt_id)?.buffer)
6254    }
6255
6256    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6257        let mut cursor = self
6258            .excerpts
6259            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6260        let locator = self.excerpt_locator_for_id(excerpt_id);
6261        if cursor.seek(&Some(locator), Bias::Left, &()) {
6262            let start = cursor.start().1.clone();
6263            let end = cursor.end(&()).1;
6264            let mut diff_transforms = self
6265                .diff_transforms
6266                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6267            diff_transforms.seek(&start, Bias::Left, &());
6268            let overshoot = start.0 - diff_transforms.start().0.0;
6269            let start = diff_transforms.start().1.0 + overshoot;
6270            diff_transforms.seek(&end, Bias::Right, &());
6271            let overshoot = end.0 - diff_transforms.start().0.0;
6272            let end = diff_transforms.start().1.0 + overshoot;
6273            Some(start..end)
6274        } else {
6275            None
6276        }
6277    }
6278
6279    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6280        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6281        let locator = self.excerpt_locator_for_id(excerpt_id);
6282        if cursor.seek(&Some(locator), Bias::Left, &()) {
6283            if let Some(excerpt) = cursor.item() {
6284                return Some(excerpt.range.context.clone());
6285            }
6286        }
6287        None
6288    }
6289
6290    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6291        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6292        let locator = self.excerpt_locator_for_id(excerpt_id);
6293        cursor.seek(&Some(locator), Bias::Left, &());
6294        if let Some(excerpt) = cursor.item() {
6295            if excerpt.id == excerpt_id {
6296                return Some(excerpt);
6297            }
6298        }
6299        None
6300    }
6301
6302    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6303    pub fn excerpt_containing<T: ToOffset>(
6304        &self,
6305        range: Range<T>,
6306    ) -> Option<MultiBufferExcerpt<'_>> {
6307        let range = range.start.to_offset(self)..range.end.to_offset(self);
6308        let mut cursor = self.cursor::<usize>();
6309        cursor.seek(&range.start);
6310
6311        let start_excerpt = cursor.excerpt()?;
6312        if range.end != range.start {
6313            cursor.seek_forward(&range.end);
6314            if cursor.excerpt()?.id != start_excerpt.id {
6315                return None;
6316            }
6317        }
6318
6319        cursor.seek_to_start_of_current_excerpt();
6320        let region = cursor.region()?;
6321        let offset = region.range.start;
6322        let buffer_offset = start_excerpt.buffer_start_offset();
6323        let excerpt_offset = cursor.excerpts.start().clone();
6324        Some(MultiBufferExcerpt {
6325            diff_transforms: cursor.diff_transforms,
6326            excerpt: start_excerpt,
6327            offset,
6328            buffer_offset,
6329            excerpt_offset,
6330        })
6331    }
6332
6333    pub fn selections_in_range<'a>(
6334        &'a self,
6335        range: &'a Range<Anchor>,
6336        include_local: bool,
6337    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6338        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6339        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6340        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6341        cursor.seek(start_locator, Bias::Left, &());
6342        cursor
6343            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6344            .flat_map(move |excerpt| {
6345                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6346                if excerpt.id == range.start.excerpt_id {
6347                    query_range.start = range.start.text_anchor;
6348                }
6349                if excerpt.id == range.end.excerpt_id {
6350                    query_range.end = range.end.text_anchor;
6351                }
6352
6353                excerpt
6354                    .buffer
6355                    .selections_in_range(query_range, include_local)
6356                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6357                        selections.map(move |selection| {
6358                            let mut start = Anchor {
6359                                buffer_id: Some(excerpt.buffer_id),
6360                                excerpt_id: excerpt.id,
6361                                text_anchor: selection.start,
6362                                diff_base_anchor: None,
6363                            };
6364                            let mut end = Anchor {
6365                                buffer_id: Some(excerpt.buffer_id),
6366                                excerpt_id: excerpt.id,
6367                                text_anchor: selection.end,
6368                                diff_base_anchor: None,
6369                            };
6370                            if range.start.cmp(&start, self).is_gt() {
6371                                start = range.start;
6372                            }
6373                            if range.end.cmp(&end, self).is_lt() {
6374                                end = range.end;
6375                            }
6376
6377                            (
6378                                replica_id,
6379                                line_mode,
6380                                cursor_shape,
6381                                Selection {
6382                                    id: selection.id,
6383                                    start,
6384                                    end,
6385                                    reversed: selection.reversed,
6386                                    goal: selection.goal,
6387                                },
6388                            )
6389                        })
6390                    })
6391            })
6392    }
6393
6394    pub fn show_headers(&self) -> bool {
6395        self.show_headers
6396    }
6397
6398    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6399        self.diffs.get(&buffer_id)
6400    }
6401}
6402
6403#[cfg(any(test, feature = "test-support"))]
6404impl MultiBufferSnapshot {
6405    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6406        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6407        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6408        start..end
6409    }
6410
6411    #[cfg(any(test, feature = "test-support"))]
6412    fn check_invariants(&self) {
6413        let excerpts = self.excerpts.items(&());
6414        let excerpt_ids = self.excerpt_ids.items(&());
6415
6416        for (ix, excerpt) in excerpts.iter().enumerate() {
6417            if ix == 0 {
6418                if excerpt.locator <= Locator::min() {
6419                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6420                }
6421            } else if excerpt.locator <= excerpts[ix - 1].locator {
6422                panic!("excerpts are out-of-order: {:?}", excerpts);
6423            }
6424        }
6425
6426        for (ix, entry) in excerpt_ids.iter().enumerate() {
6427            if ix == 0 {
6428                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6429                    panic!("invalid first excerpt id {:?}", entry.id);
6430                }
6431            } else if entry.id <= excerpt_ids[ix - 1].id {
6432                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6433            }
6434        }
6435
6436        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6437            panic!(
6438                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6439                self.excerpts.summary().text.len,
6440                self.diff_transforms.summary().input,
6441                self.diff_transforms.items(&()),
6442            );
6443        }
6444
6445        let mut prev_transform: Option<&DiffTransform> = None;
6446        for item in self.diff_transforms.iter() {
6447            if let DiffTransform::BufferContent {
6448                summary,
6449                inserted_hunk_info,
6450            } = item
6451            {
6452                if let Some(DiffTransform::BufferContent {
6453                    inserted_hunk_info: prev_inserted_hunk_info,
6454                    ..
6455                }) = prev_transform
6456                {
6457                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6458                        panic!(
6459                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6460                            self.diff_transforms.items(&())
6461                        );
6462                    }
6463                }
6464                if summary.len == 0 && !self.is_empty() {
6465                    panic!("empty buffer content transform");
6466                }
6467            }
6468            prev_transform = Some(item);
6469        }
6470    }
6471}
6472
6473impl<'a, D> MultiBufferCursor<'a, D>
6474where
6475    D: TextDimension + Ord + Sub<D, Output = D>,
6476{
6477    fn seek(&mut self, position: &D) {
6478        self.cached_region.take();
6479        self.diff_transforms
6480            .seek(&OutputDimension(*position), Bias::Right, &());
6481        if self.diff_transforms.item().is_none()
6482            && *position == self.diff_transforms.start().output_dimension.0
6483        {
6484            self.diff_transforms.prev(&());
6485        }
6486
6487        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6488        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6489            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6490            excerpt_position.add_assign(&overshoot);
6491        }
6492
6493        self.excerpts
6494            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6495        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6496            self.excerpts.prev(&());
6497        }
6498    }
6499
6500    fn seek_forward(&mut self, position: &D) {
6501        self.cached_region.take();
6502        self.diff_transforms
6503            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6504        if self.diff_transforms.item().is_none()
6505            && *position == self.diff_transforms.start().output_dimension.0
6506        {
6507            self.diff_transforms.prev(&());
6508        }
6509
6510        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6511        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6512        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6513            excerpt_position.add_assign(&overshoot);
6514        }
6515
6516        self.excerpts
6517            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6518        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6519            self.excerpts.prev(&());
6520        }
6521    }
6522
6523    fn next_excerpt(&mut self) {
6524        self.excerpts.next(&());
6525        self.seek_to_start_of_current_excerpt();
6526    }
6527
6528    fn prev_excerpt(&mut self) {
6529        self.excerpts.prev(&());
6530        self.seek_to_start_of_current_excerpt();
6531    }
6532
6533    fn seek_to_start_of_current_excerpt(&mut self) {
6534        self.cached_region.take();
6535        self.diff_transforms
6536            .seek(self.excerpts.start(), Bias::Left, &());
6537        if self.diff_transforms.end(&()).excerpt_dimension == *self.excerpts.start()
6538            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6539            && self.diff_transforms.next_item().is_some()
6540        {
6541            self.diff_transforms.next(&());
6542        }
6543    }
6544
6545    fn next(&mut self) {
6546        self.cached_region.take();
6547        match self
6548            .diff_transforms
6549            .end(&())
6550            .excerpt_dimension
6551            .cmp(&self.excerpts.end(&()))
6552        {
6553            cmp::Ordering::Less => self.diff_transforms.next(&()),
6554            cmp::Ordering::Greater => self.excerpts.next(&()),
6555            cmp::Ordering::Equal => {
6556                self.diff_transforms.next(&());
6557                if self.diff_transforms.end(&()).excerpt_dimension > self.excerpts.end(&())
6558                    || self.diff_transforms.item().is_none()
6559                {
6560                    self.excerpts.next(&());
6561                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6562                    self.diff_transforms.item()
6563                {
6564                    if self
6565                        .excerpts
6566                        .item()
6567                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6568                    {
6569                        self.excerpts.next(&());
6570                    }
6571                }
6572            }
6573        }
6574    }
6575
6576    fn prev(&mut self) {
6577        self.cached_region.take();
6578        match self
6579            .diff_transforms
6580            .start()
6581            .excerpt_dimension
6582            .cmp(self.excerpts.start())
6583        {
6584            cmp::Ordering::Less => self.excerpts.prev(&()),
6585            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6586            cmp::Ordering::Equal => {
6587                self.diff_transforms.prev(&());
6588                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6589                    || self.diff_transforms.item().is_none()
6590                {
6591                    self.excerpts.prev(&());
6592                }
6593            }
6594        }
6595    }
6596
6597    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6598        if self.cached_region.is_none() {
6599            self.cached_region = self.build_region();
6600        }
6601        self.cached_region.clone()
6602    }
6603
6604    fn is_at_start_of_excerpt(&mut self) -> bool {
6605        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6606            return false;
6607        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6608            return true;
6609        }
6610
6611        self.diff_transforms.prev(&());
6612        let prev_transform = self.diff_transforms.item();
6613        self.diff_transforms.next(&());
6614
6615        prev_transform.map_or(true, |next_transform| {
6616            matches!(next_transform, DiffTransform::BufferContent { .. })
6617        })
6618    }
6619
6620    fn is_at_end_of_excerpt(&mut self) -> bool {
6621        if self.diff_transforms.end(&()).excerpt_dimension < self.excerpts.end(&()) {
6622            return false;
6623        } else if self.diff_transforms.end(&()).excerpt_dimension > self.excerpts.end(&())
6624            || self.diff_transforms.item().is_none()
6625        {
6626            return true;
6627        }
6628
6629        let next_transform = self.diff_transforms.next_item();
6630        next_transform.map_or(true, |next_transform| match next_transform {
6631            DiffTransform::BufferContent { .. } => true,
6632            DiffTransform::DeletedHunk { hunk_info, .. } => self
6633                .excerpts
6634                .item()
6635                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6636        })
6637    }
6638
6639    fn main_buffer_position(&self) -> Option<D> {
6640        let excerpt = self.excerpts.item()?;
6641        let buffer = &excerpt.buffer;
6642        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6643        let mut buffer_start = buffer_context_start;
6644        let overshoot = self.diff_transforms.end(&()).excerpt_dimension.0 - self.excerpts.start().0;
6645        buffer_start.add_assign(&overshoot);
6646        Some(buffer_start)
6647    }
6648
6649    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6650        let excerpt = self.excerpts.item()?;
6651        match self.diff_transforms.item()? {
6652            DiffTransform::DeletedHunk {
6653                buffer_id,
6654                base_text_byte_range,
6655                has_trailing_newline,
6656                hunk_info,
6657                ..
6658            } => {
6659                let diff = self.diffs.get(&buffer_id)?;
6660                let buffer = diff.base_text();
6661                let mut rope_cursor = buffer.as_rope().cursor(0);
6662                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6663                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6664                let mut buffer_end = buffer_start;
6665                buffer_end.add_assign(&buffer_range_len);
6666                let start = self.diff_transforms.start().output_dimension.0;
6667                let end = self.diff_transforms.end(&()).output_dimension.0;
6668                return Some(MultiBufferRegion {
6669                    buffer,
6670                    excerpt,
6671                    has_trailing_newline: *has_trailing_newline,
6672                    is_main_buffer: false,
6673                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6674                        hunk_info.hunk_secondary_status,
6675                    )),
6676                    buffer_range: buffer_start..buffer_end,
6677                    range: start..end,
6678                });
6679            }
6680            DiffTransform::BufferContent {
6681                inserted_hunk_info, ..
6682            } => {
6683                let buffer = &excerpt.buffer;
6684                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6685
6686                let mut start = self.diff_transforms.start().output_dimension.0;
6687                let mut buffer_start = buffer_context_start;
6688                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6689                    let overshoot =
6690                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6691                    start.add_assign(&overshoot);
6692                } else {
6693                    let overshoot =
6694                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6695                    buffer_start.add_assign(&overshoot);
6696                }
6697
6698                let mut end;
6699                let mut buffer_end;
6700                let has_trailing_newline;
6701                if self.diff_transforms.end(&()).excerpt_dimension.0 < self.excerpts.end(&()).0 {
6702                    let overshoot =
6703                        self.diff_transforms.end(&()).excerpt_dimension.0 - self.excerpts.start().0;
6704                    end = self.diff_transforms.end(&()).output_dimension.0;
6705                    buffer_end = buffer_context_start;
6706                    buffer_end.add_assign(&overshoot);
6707                    has_trailing_newline = false;
6708                } else {
6709                    let overshoot =
6710                        self.excerpts.end(&()).0 - self.diff_transforms.start().excerpt_dimension.0;
6711                    end = self.diff_transforms.start().output_dimension.0;
6712                    end.add_assign(&overshoot);
6713                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6714                    has_trailing_newline = excerpt.has_trailing_newline;
6715                };
6716
6717                Some(MultiBufferRegion {
6718                    buffer,
6719                    excerpt,
6720                    has_trailing_newline,
6721                    is_main_buffer: true,
6722                    diff_hunk_status: inserted_hunk_info
6723                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6724                    buffer_range: buffer_start..buffer_end,
6725                    range: start..end,
6726                })
6727            }
6728        }
6729    }
6730
6731    fn excerpt(&self) -> Option<&'a Excerpt> {
6732        self.excerpts.item()
6733    }
6734}
6735
6736impl History {
6737    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6738        self.transaction_depth += 1;
6739        if self.transaction_depth == 1 {
6740            let id = self.next_transaction_id.tick();
6741            self.undo_stack.push(Transaction {
6742                id,
6743                buffer_transactions: Default::default(),
6744                first_edit_at: now,
6745                last_edit_at: now,
6746                suppress_grouping: false,
6747            });
6748            Some(id)
6749        } else {
6750            None
6751        }
6752    }
6753
6754    fn end_transaction(
6755        &mut self,
6756        now: Instant,
6757        buffer_transactions: HashMap<BufferId, TransactionId>,
6758    ) -> bool {
6759        assert_ne!(self.transaction_depth, 0);
6760        self.transaction_depth -= 1;
6761        if self.transaction_depth == 0 {
6762            if buffer_transactions.is_empty() {
6763                self.undo_stack.pop();
6764                false
6765            } else {
6766                self.redo_stack.clear();
6767                let transaction = self.undo_stack.last_mut().unwrap();
6768                transaction.last_edit_at = now;
6769                for (buffer_id, transaction_id) in buffer_transactions {
6770                    transaction
6771                        .buffer_transactions
6772                        .entry(buffer_id)
6773                        .or_insert(transaction_id);
6774                }
6775                true
6776            }
6777        } else {
6778            false
6779        }
6780    }
6781
6782    fn push_transaction<'a, T>(
6783        &mut self,
6784        buffer_transactions: T,
6785        now: Instant,
6786        cx: &Context<MultiBuffer>,
6787    ) where
6788        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6789    {
6790        assert_eq!(self.transaction_depth, 0);
6791        let transaction = Transaction {
6792            id: self.next_transaction_id.tick(),
6793            buffer_transactions: buffer_transactions
6794                .into_iter()
6795                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6796                .collect(),
6797            first_edit_at: now,
6798            last_edit_at: now,
6799            suppress_grouping: false,
6800        };
6801        if !transaction.buffer_transactions.is_empty() {
6802            self.undo_stack.push(transaction);
6803            self.redo_stack.clear();
6804        }
6805    }
6806
6807    fn finalize_last_transaction(&mut self) {
6808        if let Some(transaction) = self.undo_stack.last_mut() {
6809            transaction.suppress_grouping = true;
6810        }
6811    }
6812
6813    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6814        if let Some(ix) = self
6815            .undo_stack
6816            .iter()
6817            .rposition(|transaction| transaction.id == transaction_id)
6818        {
6819            Some(self.undo_stack.remove(ix))
6820        } else if let Some(ix) = self
6821            .redo_stack
6822            .iter()
6823            .rposition(|transaction| transaction.id == transaction_id)
6824        {
6825            Some(self.redo_stack.remove(ix))
6826        } else {
6827            None
6828        }
6829    }
6830
6831    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6832        self.undo_stack
6833            .iter()
6834            .find(|transaction| transaction.id == transaction_id)
6835            .or_else(|| {
6836                self.redo_stack
6837                    .iter()
6838                    .find(|transaction| transaction.id == transaction_id)
6839            })
6840    }
6841
6842    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6843        self.undo_stack
6844            .iter_mut()
6845            .find(|transaction| transaction.id == transaction_id)
6846            .or_else(|| {
6847                self.redo_stack
6848                    .iter_mut()
6849                    .find(|transaction| transaction.id == transaction_id)
6850            })
6851    }
6852
6853    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6854        assert_eq!(self.transaction_depth, 0);
6855        if let Some(transaction) = self.undo_stack.pop() {
6856            self.redo_stack.push(transaction);
6857            self.redo_stack.last_mut()
6858        } else {
6859            None
6860        }
6861    }
6862
6863    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6864        assert_eq!(self.transaction_depth, 0);
6865        if let Some(transaction) = self.redo_stack.pop() {
6866            self.undo_stack.push(transaction);
6867            self.undo_stack.last_mut()
6868        } else {
6869            None
6870        }
6871    }
6872
6873    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6874        let ix = self
6875            .undo_stack
6876            .iter()
6877            .rposition(|transaction| transaction.id == transaction_id)?;
6878        let transaction = self.undo_stack.remove(ix);
6879        self.redo_stack.push(transaction);
6880        self.redo_stack.last()
6881    }
6882
6883    fn group(&mut self) -> Option<TransactionId> {
6884        let mut count = 0;
6885        let mut transactions = self.undo_stack.iter();
6886        if let Some(mut transaction) = transactions.next_back() {
6887            while let Some(prev_transaction) = transactions.next_back() {
6888                if !prev_transaction.suppress_grouping
6889                    && transaction.first_edit_at - prev_transaction.last_edit_at
6890                        <= self.group_interval
6891                {
6892                    transaction = prev_transaction;
6893                    count += 1;
6894                } else {
6895                    break;
6896                }
6897            }
6898        }
6899        self.group_trailing(count)
6900    }
6901
6902    fn group_until(&mut self, transaction_id: TransactionId) {
6903        let mut count = 0;
6904        for transaction in self.undo_stack.iter().rev() {
6905            if transaction.id == transaction_id {
6906                self.group_trailing(count);
6907                break;
6908            } else if transaction.suppress_grouping {
6909                break;
6910            } else {
6911                count += 1;
6912            }
6913        }
6914    }
6915
6916    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6917        let new_len = self.undo_stack.len() - n;
6918        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6919        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6920            if let Some(transaction) = transactions_to_merge.last() {
6921                last_transaction.last_edit_at = transaction.last_edit_at;
6922            }
6923            for to_merge in transactions_to_merge {
6924                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6925                    last_transaction
6926                        .buffer_transactions
6927                        .entry(*buffer_id)
6928                        .or_insert(*transaction_id);
6929                }
6930            }
6931        }
6932
6933        self.undo_stack.truncate(new_len);
6934        self.undo_stack.last().map(|t| t.id)
6935    }
6936}
6937
6938impl Excerpt {
6939    fn new(
6940        id: ExcerptId,
6941        locator: Locator,
6942        buffer_id: BufferId,
6943        buffer: BufferSnapshot,
6944        range: ExcerptRange<text::Anchor>,
6945        has_trailing_newline: bool,
6946    ) -> Self {
6947        Excerpt {
6948            id,
6949            locator,
6950            max_buffer_row: range.context.end.to_point(&buffer).row,
6951            text_summary: buffer
6952                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6953            buffer_id,
6954            buffer,
6955            range,
6956            has_trailing_newline,
6957        }
6958    }
6959
6960    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6961        let content_start = self.range.context.start.to_offset(&self.buffer);
6962        let chunks_start = content_start + range.start;
6963        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6964
6965        let footer_height = if self.has_trailing_newline
6966            && range.start <= self.text_summary.len
6967            && range.end > self.text_summary.len
6968        {
6969            1
6970        } else {
6971            0
6972        };
6973
6974        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6975
6976        ExcerptChunks {
6977            excerpt_id: self.id,
6978            content_chunks,
6979            footer_height,
6980        }
6981    }
6982
6983    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6984        let content_start = self.range.context.start.to_offset(&self.buffer);
6985        let chunks_start = content_start + range.start;
6986        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6987        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6988        excerpt_chunks.footer_height = if self.has_trailing_newline
6989            && range.start <= self.text_summary.len
6990            && range.end > self.text_summary.len
6991        {
6992            1
6993        } else {
6994            0
6995        };
6996    }
6997
6998    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6999        if text_anchor
7000            .cmp(&self.range.context.start, &self.buffer)
7001            .is_lt()
7002        {
7003            self.range.context.start
7004        } else if text_anchor
7005            .cmp(&self.range.context.end, &self.buffer)
7006            .is_gt()
7007        {
7008            self.range.context.end
7009        } else {
7010            text_anchor
7011        }
7012    }
7013
7014    fn contains(&self, anchor: &Anchor) -> bool {
7015        Some(self.buffer_id) == anchor.buffer_id
7016            && self
7017                .range
7018                .context
7019                .start
7020                .cmp(&anchor.text_anchor, &self.buffer)
7021                .is_le()
7022            && self
7023                .range
7024                .context
7025                .end
7026                .cmp(&anchor.text_anchor, &self.buffer)
7027                .is_ge()
7028    }
7029
7030    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7031    fn buffer_start_offset(&self) -> usize {
7032        self.range.context.start.to_offset(&self.buffer)
7033    }
7034
7035    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7036    fn buffer_end_offset(&self) -> usize {
7037        self.buffer_start_offset() + self.text_summary.len
7038    }
7039}
7040
7041impl<'a> MultiBufferExcerpt<'a> {
7042    pub fn id(&self) -> ExcerptId {
7043        self.excerpt.id
7044    }
7045
7046    pub fn buffer_id(&self) -> BufferId {
7047        self.excerpt.buffer_id
7048    }
7049
7050    pub fn start_anchor(&self) -> Anchor {
7051        Anchor {
7052            buffer_id: Some(self.excerpt.buffer_id),
7053            excerpt_id: self.excerpt.id,
7054            text_anchor: self.excerpt.range.context.start,
7055            diff_base_anchor: None,
7056        }
7057    }
7058
7059    pub fn end_anchor(&self) -> Anchor {
7060        Anchor {
7061            buffer_id: Some(self.excerpt.buffer_id),
7062            excerpt_id: self.excerpt.id,
7063            text_anchor: self.excerpt.range.context.end,
7064            diff_base_anchor: None,
7065        }
7066    }
7067
7068    pub fn buffer(&self) -> &'a BufferSnapshot {
7069        &self.excerpt.buffer
7070    }
7071
7072    pub fn buffer_range(&self) -> Range<usize> {
7073        self.buffer_offset
7074            ..self
7075                .excerpt
7076                .range
7077                .context
7078                .end
7079                .to_offset(&self.excerpt.buffer.text)
7080    }
7081
7082    pub fn start_offset(&self) -> usize {
7083        self.offset
7084    }
7085
7086    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7087    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
7088        self.map_range_to_buffer(offset..offset).start
7089    }
7090
7091    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7092    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
7093        self.diff_transforms
7094            .seek(&OutputDimension(range.start), Bias::Right, &());
7095        let start = self.map_offset_to_buffer_internal(range.start);
7096        let end = if range.end > range.start {
7097            self.diff_transforms
7098                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
7099            self.map_offset_to_buffer_internal(range.end)
7100        } else {
7101            start
7102        };
7103        start..end
7104    }
7105
7106    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
7107        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
7108        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7109            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
7110        };
7111        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
7112        self.buffer_offset + offset_in_excerpt
7113    }
7114
7115    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7116    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
7117        self.map_range_from_buffer(buffer_offset..buffer_offset)
7118            .start
7119    }
7120
7121    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7122    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
7123        if buffer_range.start < self.buffer_offset {
7124            log::warn!(
7125                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7126            );
7127            return buffer_range;
7128        }
7129        let overshoot = buffer_range.start - self.buffer_offset;
7130        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7131        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
7132        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
7133            log::warn!(
7134                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7135            );
7136            return buffer_range;
7137        }
7138        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7139        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7140
7141        let end = if buffer_range.end > buffer_range.start {
7142            let overshoot = buffer_range.end - self.buffer_offset;
7143            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7144            self.diff_transforms
7145                .seek_forward(&excerpt_offset, Bias::Right, &());
7146            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7147            self.diff_transforms.start().output_dimension.0 + overshoot
7148        } else {
7149            start
7150        };
7151
7152        start..end
7153    }
7154
7155    /// Returns true if the entirety of the given range is in the buffer's excerpt
7156    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
7157        range.start >= self.excerpt.buffer_start_offset()
7158            && range.end <= self.excerpt.buffer_end_offset()
7159    }
7160
7161    pub fn max_buffer_row(&self) -> u32 {
7162        self.excerpt.max_buffer_row
7163    }
7164}
7165
7166impl ExcerptId {
7167    pub fn min() -> Self {
7168        Self(0)
7169    }
7170
7171    pub fn max() -> Self {
7172        Self(usize::MAX)
7173    }
7174
7175    pub fn to_proto(&self) -> u64 {
7176        self.0 as _
7177    }
7178
7179    pub fn from_proto(proto: u64) -> Self {
7180        Self(proto as _)
7181    }
7182
7183    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7184        let a = snapshot.excerpt_locator_for_id(*self);
7185        let b = snapshot.excerpt_locator_for_id(*other);
7186        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7187    }
7188}
7189
7190impl From<ExcerptId> for usize {
7191    fn from(val: ExcerptId) -> Self {
7192        val.0
7193    }
7194}
7195
7196impl fmt::Debug for Excerpt {
7197    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7198        f.debug_struct("Excerpt")
7199            .field("id", &self.id)
7200            .field("locator", &self.locator)
7201            .field("buffer_id", &self.buffer_id)
7202            .field("range", &self.range)
7203            .field("text_summary", &self.text_summary)
7204            .field("has_trailing_newline", &self.has_trailing_newline)
7205            .finish()
7206    }
7207}
7208
7209impl sum_tree::Item for Excerpt {
7210    type Summary = ExcerptSummary;
7211
7212    fn summary(&self, _cx: &()) -> Self::Summary {
7213        let mut text = self.text_summary;
7214        if self.has_trailing_newline {
7215            text += TextSummary::from("\n");
7216        }
7217        ExcerptSummary {
7218            excerpt_id: self.id,
7219            excerpt_locator: self.locator.clone(),
7220            widest_line_number: self.max_buffer_row,
7221            text,
7222        }
7223    }
7224}
7225
7226impl sum_tree::Item for ExcerptIdMapping {
7227    type Summary = ExcerptId;
7228
7229    fn summary(&self, _cx: &()) -> Self::Summary {
7230        self.id
7231    }
7232}
7233
7234impl sum_tree::KeyedItem for ExcerptIdMapping {
7235    type Key = ExcerptId;
7236
7237    fn key(&self) -> Self::Key {
7238        self.id
7239    }
7240}
7241
7242impl DiffTransform {
7243    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7244        match self {
7245            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7246            DiffTransform::BufferContent {
7247                inserted_hunk_info, ..
7248            } => *inserted_hunk_info,
7249        }
7250    }
7251}
7252
7253impl sum_tree::Item for DiffTransform {
7254    type Summary = DiffTransformSummary;
7255
7256    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7257        match self {
7258            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7259                input: *summary,
7260                output: *summary,
7261            },
7262            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7263                input: TextSummary::default(),
7264                output: *summary,
7265            },
7266        }
7267    }
7268}
7269
7270impl DiffTransformSummary {
7271    fn excerpt_len(&self) -> ExcerptOffset {
7272        ExcerptOffset::new(self.input.len)
7273    }
7274}
7275
7276impl sum_tree::Summary for DiffTransformSummary {
7277    type Context = ();
7278
7279    fn zero(_: &Self::Context) -> Self {
7280        DiffTransformSummary {
7281            input: TextSummary::default(),
7282            output: TextSummary::default(),
7283        }
7284    }
7285
7286    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7287        self.input += &summary.input;
7288        self.output += &summary.output;
7289    }
7290}
7291
7292impl sum_tree::Summary for ExcerptId {
7293    type Context = ();
7294
7295    fn zero(_cx: &()) -> Self {
7296        Default::default()
7297    }
7298
7299    fn add_summary(&mut self, other: &Self, _: &()) {
7300        *self = *other;
7301    }
7302}
7303
7304impl sum_tree::Summary for ExcerptSummary {
7305    type Context = ();
7306
7307    fn zero(_cx: &()) -> Self {
7308        Default::default()
7309    }
7310
7311    fn add_summary(&mut self, summary: &Self, _: &()) {
7312        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7313        self.excerpt_locator = summary.excerpt_locator.clone();
7314        Summary::add_summary(&mut self.text, &summary.text, &());
7315        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7316    }
7317}
7318
7319impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7320    fn zero(_cx: &()) -> Self {
7321        Default::default()
7322    }
7323
7324    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7325        self.value += summary.text.len;
7326    }
7327}
7328
7329impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7330    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7331        Ord::cmp(&self.value, &cursor_location.text.len)
7332    }
7333}
7334
7335impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7336    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7337        Ord::cmp(&Some(self), cursor_location)
7338    }
7339}
7340
7341impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7342    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7343        Ord::cmp(self, &cursor_location.excerpt_locator)
7344    }
7345}
7346
7347impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7348    fn zero(_cx: &()) -> Self {
7349        Default::default()
7350    }
7351
7352    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7353        self.value += summary.text.lines;
7354    }
7355}
7356
7357impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7358    for ExcerptDimension<D>
7359{
7360    fn zero(_: &()) -> Self {
7361        ExcerptDimension(D::default())
7362    }
7363
7364    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7365        self.0.add_assign(&D::from_text_summary(&summary.text))
7366    }
7367}
7368
7369impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7370    fn zero(_cx: &()) -> Self {
7371        Default::default()
7372    }
7373
7374    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7375        *self = Some(&summary.excerpt_locator);
7376    }
7377}
7378
7379impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7380    fn zero(_cx: &()) -> Self {
7381        Default::default()
7382    }
7383
7384    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7385        *self = Some(summary.excerpt_id);
7386    }
7387}
7388
7389#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7390struct ExcerptDimension<T>(T);
7391
7392#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7393struct OutputDimension<T>(T);
7394
7395impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7396    fn zero(_: &()) -> Self {
7397        ExcerptOffset::new(0)
7398    }
7399
7400    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7401        self.value += summary.input.len;
7402    }
7403}
7404
7405impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7406    fn zero(_: &()) -> Self {
7407        ExcerptPoint::new(0, 0)
7408    }
7409
7410    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7411        self.value += summary.input.lines;
7412    }
7413}
7414
7415impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7416    for ExcerptDimension<D>
7417{
7418    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7419        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7420    }
7421}
7422
7423impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7424    for ExcerptDimension<D>
7425{
7426    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7427        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7428    }
7429}
7430
7431impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7432    fn zero(_: &()) -> Self {
7433        ExcerptDimension(D::default())
7434    }
7435
7436    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7437        self.0.add_assign(&D::from_text_summary(&summary.input))
7438    }
7439}
7440
7441impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7442    for OutputDimension<D>
7443{
7444    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7445        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7446    }
7447}
7448
7449impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7450    fn zero(_: &()) -> Self {
7451        OutputDimension(D::default())
7452    }
7453
7454    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7455        self.0.add_assign(&D::from_text_summary(&summary.output))
7456    }
7457}
7458
7459impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7460    fn zero(_: &()) -> Self {
7461        TextSummary::default()
7462    }
7463
7464    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7465        *self += summary.output
7466    }
7467}
7468
7469impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7470    fn zero(_: &()) -> Self {
7471        0
7472    }
7473
7474    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7475        *self += summary.output.len
7476    }
7477}
7478
7479impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7480    fn zero(_: &()) -> Self {
7481        Point::new(0, 0)
7482    }
7483
7484    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7485        *self += summary.output.lines
7486    }
7487}
7488
7489impl MultiBufferRows<'_> {
7490    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7491        self.point = Point::new(row, 0);
7492        self.cursor.seek(&self.point);
7493    }
7494}
7495
7496impl Iterator for MultiBufferRows<'_> {
7497    type Item = RowInfo;
7498
7499    fn next(&mut self) -> Option<Self::Item> {
7500        if self.is_empty && self.point.row == 0 {
7501            self.point += Point::new(1, 0);
7502            return Some(RowInfo {
7503                buffer_id: None,
7504                buffer_row: Some(0),
7505                multibuffer_row: Some(MultiBufferRow(0)),
7506                diff_status: None,
7507                expand_info: None,
7508            });
7509        }
7510
7511        let mut region = self.cursor.region()?;
7512        while self.point >= region.range.end {
7513            self.cursor.next();
7514            if let Some(next_region) = self.cursor.region() {
7515                region = next_region;
7516            } else {
7517                if self.point == self.cursor.diff_transforms.end(&()).output_dimension.0 {
7518                    let multibuffer_row = MultiBufferRow(self.point.row);
7519                    let last_excerpt = self
7520                        .cursor
7521                        .excerpts
7522                        .item()
7523                        .or(self.cursor.excerpts.prev_item())?;
7524                    let last_row = last_excerpt
7525                        .range
7526                        .context
7527                        .end
7528                        .to_point(&last_excerpt.buffer)
7529                        .row;
7530
7531                    let first_row = last_excerpt
7532                        .range
7533                        .context
7534                        .start
7535                        .to_point(&last_excerpt.buffer)
7536                        .row;
7537
7538                    let expand_info = if self.is_singleton {
7539                        None
7540                    } else {
7541                        let needs_expand_up = first_row == last_row
7542                            && last_row > 0
7543                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7544                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7545
7546                        if needs_expand_up && needs_expand_down {
7547                            Some(ExpandExcerptDirection::UpAndDown)
7548                        } else if needs_expand_up {
7549                            Some(ExpandExcerptDirection::Up)
7550                        } else if needs_expand_down {
7551                            Some(ExpandExcerptDirection::Down)
7552                        } else {
7553                            None
7554                        }
7555                        .map(|direction| ExpandInfo {
7556                            direction,
7557                            excerpt_id: last_excerpt.id,
7558                        })
7559                    };
7560                    self.point += Point::new(1, 0);
7561                    return Some(RowInfo {
7562                        buffer_id: Some(last_excerpt.buffer_id),
7563                        buffer_row: Some(last_row),
7564                        multibuffer_row: Some(multibuffer_row),
7565                        diff_status: None,
7566                        expand_info,
7567                    });
7568                } else {
7569                    return None;
7570                }
7571            };
7572        }
7573
7574        let overshoot = self.point - region.range.start;
7575        let buffer_point = region.buffer_range.start + overshoot;
7576        let expand_info = if self.is_singleton {
7577            None
7578        } else {
7579            let needs_expand_up = self.point.row == region.range.start.row
7580                && self.cursor.is_at_start_of_excerpt()
7581                && buffer_point.row > 0;
7582            let needs_expand_down = (region.excerpt.has_trailing_newline
7583                && self.point.row + 1 == region.range.end.row
7584                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7585                && self.cursor.is_at_end_of_excerpt()
7586                && buffer_point.row < region.buffer.max_point().row;
7587
7588            if needs_expand_up && needs_expand_down {
7589                Some(ExpandExcerptDirection::UpAndDown)
7590            } else if needs_expand_up {
7591                Some(ExpandExcerptDirection::Up)
7592            } else if needs_expand_down {
7593                Some(ExpandExcerptDirection::Down)
7594            } else {
7595                None
7596            }
7597            .map(|direction| ExpandInfo {
7598                direction,
7599                excerpt_id: region.excerpt.id,
7600            })
7601        };
7602
7603        let result = Some(RowInfo {
7604            buffer_id: Some(region.buffer.remote_id()),
7605            buffer_row: Some(buffer_point.row),
7606            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7607            diff_status: region
7608                .diff_hunk_status
7609                .filter(|_| self.point < region.range.end),
7610            expand_info,
7611        });
7612        self.point += Point::new(1, 0);
7613        result
7614    }
7615}
7616
7617impl<'a> MultiBufferChunks<'a> {
7618    pub fn offset(&self) -> usize {
7619        self.range.start
7620    }
7621
7622    pub fn seek(&mut self, range: Range<usize>) {
7623        self.diff_transforms.seek(&range.end, Bias::Right, &());
7624        let mut excerpt_end = self.diff_transforms.start().1;
7625        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7626            let overshoot = range.end - self.diff_transforms.start().0;
7627            excerpt_end.value += overshoot;
7628        }
7629
7630        self.diff_transforms.seek(&range.start, Bias::Right, &());
7631        let mut excerpt_start = self.diff_transforms.start().1;
7632        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7633            let overshoot = range.start - self.diff_transforms.start().0;
7634            excerpt_start.value += overshoot;
7635        }
7636
7637        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7638        self.buffer_chunk.take();
7639        self.range = range;
7640    }
7641
7642    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7643        self.excerpt_offset_range = new_range.clone();
7644        self.excerpts.seek(&new_range.start, Bias::Right, &());
7645        if let Some(excerpt) = self.excerpts.item() {
7646            let excerpt_start = *self.excerpts.start();
7647            if let Some(excerpt_chunks) = self
7648                .excerpt_chunks
7649                .as_mut()
7650                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7651            {
7652                excerpt.seek_chunks(
7653                    excerpt_chunks,
7654                    (self.excerpt_offset_range.start - excerpt_start).value
7655                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7656                );
7657            } else {
7658                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7659                    (self.excerpt_offset_range.start - excerpt_start).value
7660                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7661                    self.language_aware,
7662                ));
7663            }
7664        } else {
7665            self.excerpt_chunks = None;
7666        }
7667    }
7668
7669    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7670        loop {
7671            if self.excerpt_offset_range.is_empty() {
7672                return None;
7673            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7674                self.excerpt_offset_range.start.value += chunk.text.len();
7675                return Some(chunk);
7676            } else {
7677                self.excerpts.next(&());
7678                let excerpt = self.excerpts.item()?;
7679                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7680                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7681                    self.language_aware,
7682                ));
7683            }
7684        }
7685    }
7686}
7687
7688impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7689    type Item = &'a str;
7690
7691    fn next(&mut self) -> Option<Self::Item> {
7692        let mut region = self.cursor.region()?;
7693        if self.offset == region.range.start {
7694            self.cursor.prev();
7695            region = self.cursor.region()?;
7696            let start_overshoot = self.start.saturating_sub(region.range.start);
7697            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7698                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7699            ));
7700        }
7701
7702        if self.offset == region.range.end && region.has_trailing_newline {
7703            self.offset -= 1;
7704            Some("\n")
7705        } else {
7706            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7707            self.offset -= chunk.len();
7708            Some(chunk)
7709        }
7710    }
7711}
7712
7713impl<'a> Iterator for MultiBufferChunks<'a> {
7714    type Item = Chunk<'a>;
7715
7716    fn next(&mut self) -> Option<Chunk<'a>> {
7717        if self.range.start >= self.range.end {
7718            return None;
7719        }
7720        if self.range.start == self.diff_transforms.end(&()).0 {
7721            self.diff_transforms.next(&());
7722        }
7723
7724        let diff_transform_start = self.diff_transforms.start().0;
7725        let diff_transform_end = self.diff_transforms.end(&()).0;
7726        debug_assert!(self.range.start < diff_transform_end);
7727
7728        let diff_transform = self.diff_transforms.item()?;
7729        match diff_transform {
7730            DiffTransform::BufferContent { .. } => {
7731                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7732                    chunk
7733                } else {
7734                    let chunk = self.next_excerpt_chunk().unwrap();
7735                    self.buffer_chunk.insert(chunk)
7736                };
7737
7738                let chunk_end = self.range.start + chunk.text.len();
7739                let diff_transform_end = diff_transform_end.min(self.range.end);
7740
7741                if diff_transform_end < chunk_end {
7742                    let (before, after) =
7743                        chunk.text.split_at(diff_transform_end - self.range.start);
7744                    self.range.start = diff_transform_end;
7745                    chunk.text = after;
7746                    Some(Chunk {
7747                        text: before,
7748                        ..chunk.clone()
7749                    })
7750                } else {
7751                    self.range.start = chunk_end;
7752                    self.buffer_chunk.take()
7753                }
7754            }
7755            DiffTransform::DeletedHunk {
7756                buffer_id,
7757                base_text_byte_range,
7758                has_trailing_newline,
7759                ..
7760            } => {
7761                let base_text_start =
7762                    base_text_byte_range.start + self.range.start - diff_transform_start;
7763                let base_text_end =
7764                    base_text_byte_range.start + self.range.end - diff_transform_start;
7765                let base_text_end = base_text_end.min(base_text_byte_range.end);
7766
7767                let mut chunks = if let Some((_, mut chunks)) = self
7768                    .diff_base_chunks
7769                    .take()
7770                    .filter(|(id, _)| id == buffer_id)
7771                {
7772                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7773                    {
7774                        chunks.seek(base_text_start..base_text_end);
7775                    }
7776                    chunks
7777                } else {
7778                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7779                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7780                };
7781
7782                let chunk = if let Some(chunk) = chunks.next() {
7783                    self.range.start += chunk.text.len();
7784                    self.diff_base_chunks = Some((*buffer_id, chunks));
7785                    chunk
7786                } else {
7787                    debug_assert!(has_trailing_newline);
7788                    self.range.start += "\n".len();
7789                    Chunk {
7790                        text: "\n",
7791                        ..Default::default()
7792                    }
7793                };
7794                Some(chunk)
7795            }
7796        }
7797    }
7798}
7799
7800impl MultiBufferBytes<'_> {
7801    fn consume(&mut self, len: usize) {
7802        self.range.start += len;
7803        self.chunk = &self.chunk[len..];
7804
7805        if !self.range.is_empty() && self.chunk.is_empty() {
7806            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7807                self.chunk = chunk;
7808            } else if self.has_trailing_newline {
7809                self.has_trailing_newline = false;
7810                self.chunk = b"\n";
7811            } else {
7812                self.cursor.next();
7813                if let Some(region) = self.cursor.region() {
7814                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7815                        region.buffer_range.start
7816                            ..(region.buffer_range.start + self.range.end - region.range.start)
7817                                .min(region.buffer_range.end),
7818                    );
7819                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7820                    self.excerpt_bytes = Some(excerpt_bytes);
7821                    self.has_trailing_newline =
7822                        region.has_trailing_newline && self.range.end >= region.range.end;
7823                    if self.chunk.is_empty() && self.has_trailing_newline {
7824                        self.has_trailing_newline = false;
7825                        self.chunk = b"\n";
7826                    }
7827                }
7828            }
7829        }
7830    }
7831}
7832
7833impl<'a> Iterator for MultiBufferBytes<'a> {
7834    type Item = &'a [u8];
7835
7836    fn next(&mut self) -> Option<Self::Item> {
7837        let chunk = self.chunk;
7838        if chunk.is_empty() {
7839            None
7840        } else {
7841            self.consume(chunk.len());
7842            Some(chunk)
7843        }
7844    }
7845}
7846
7847impl io::Read for MultiBufferBytes<'_> {
7848    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7849        let len = cmp::min(buf.len(), self.chunk.len());
7850        buf[..len].copy_from_slice(&self.chunk[..len]);
7851        if len > 0 {
7852            self.consume(len);
7853        }
7854        Ok(len)
7855    }
7856}
7857
7858impl io::Read for ReversedMultiBufferBytes<'_> {
7859    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7860        let len = cmp::min(buf.len(), self.chunk.len());
7861        buf[..len].copy_from_slice(&self.chunk[..len]);
7862        buf[..len].reverse();
7863        if len > 0 {
7864            self.range.end -= len;
7865            self.chunk = &self.chunk[..self.chunk.len() - len];
7866            if !self.range.is_empty() && self.chunk.is_empty() {
7867                if let Some(chunk) = self.chunks.next() {
7868                    self.chunk = chunk.as_bytes();
7869                }
7870            }
7871        }
7872        Ok(len)
7873    }
7874}
7875
7876impl<'a> Iterator for ExcerptChunks<'a> {
7877    type Item = Chunk<'a>;
7878
7879    fn next(&mut self) -> Option<Self::Item> {
7880        if let Some(chunk) = self.content_chunks.next() {
7881            return Some(chunk);
7882        }
7883
7884        if self.footer_height > 0 {
7885            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7886            self.footer_height = 0;
7887            return Some(Chunk {
7888                text,
7889                ..Default::default()
7890            });
7891        }
7892
7893        None
7894    }
7895}
7896
7897impl ToOffset for Point {
7898    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7899        snapshot.point_to_offset(*self)
7900    }
7901}
7902
7903impl ToOffset for usize {
7904    #[track_caller]
7905    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7906        assert!(
7907            *self <= snapshot.len(),
7908            "offset {} is greater than the snapshot.len() {}",
7909            *self,
7910            snapshot.len(),
7911        );
7912        *self
7913    }
7914}
7915
7916impl ToOffset for OffsetUtf16 {
7917    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7918        snapshot.offset_utf16_to_offset(*self)
7919    }
7920}
7921
7922impl ToOffset for PointUtf16 {
7923    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7924        snapshot.point_utf16_to_offset(*self)
7925    }
7926}
7927
7928impl ToOffsetUtf16 for OffsetUtf16 {
7929    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7930        *self
7931    }
7932}
7933
7934impl ToOffsetUtf16 for usize {
7935    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7936        snapshot.offset_to_offset_utf16(*self)
7937    }
7938}
7939
7940impl ToPoint for usize {
7941    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7942        snapshot.offset_to_point(*self)
7943    }
7944}
7945
7946impl ToPoint for Point {
7947    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7948        *self
7949    }
7950}
7951
7952impl ToPointUtf16 for usize {
7953    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7954        snapshot.offset_to_point_utf16(*self)
7955    }
7956}
7957
7958impl ToPointUtf16 for Point {
7959    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7960        snapshot.point_to_point_utf16(*self)
7961    }
7962}
7963
7964impl ToPointUtf16 for PointUtf16 {
7965    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7966        *self
7967    }
7968}
7969
7970impl From<ExcerptId> for EntityId {
7971    fn from(id: ExcerptId) -> Self {
7972        EntityId::from(id.0 as u64)
7973    }
7974}