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