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
1125                .read(cx)
1126                .peek_undo_stack()
1127                .map(|history_entry| history_entry.transaction_id());
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.read(cx).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 set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2640        self.snapshot.borrow_mut().all_diff_hunks_expanded = false;
2641        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2642    }
2643
2644    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2645        self.read(cx)
2646            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2647            .nth(1)
2648            .is_some()
2649    }
2650
2651    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2652        let snapshot = self.read(cx);
2653        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2654        let offset_range = range.to_offset(&snapshot);
2655        cursor.seek(&offset_range.start, Bias::Left, &());
2656        while let Some(item) = cursor.item() {
2657            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2658                break;
2659            }
2660            if item.hunk_info().is_some() {
2661                return true;
2662            }
2663            cursor.next(&());
2664        }
2665        false
2666    }
2667
2668    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2669        let snapshot = self.read(cx);
2670        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2671        for range in ranges {
2672            let range = range.to_point(&snapshot);
2673            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2674            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2675            let start = start.saturating_sub(1);
2676            let end = snapshot.len().min(end + 1);
2677            cursor.seek(&start, Bias::Right, &());
2678            while let Some(item) = cursor.item() {
2679                if *cursor.start() >= end {
2680                    break;
2681                }
2682                if item.hunk_info().is_some() {
2683                    return true;
2684                }
2685                cursor.next(&());
2686            }
2687        }
2688        false
2689    }
2690
2691    pub fn expand_or_collapse_diff_hunks_inner(
2692        &mut self,
2693        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2694        expand: bool,
2695        cx: &mut Context<Self>,
2696    ) {
2697        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2698            return;
2699        }
2700        self.sync(cx);
2701        let mut snapshot = self.snapshot.borrow_mut();
2702        let mut excerpt_edits = Vec::new();
2703        let mut last_hunk_row = None;
2704        for (range, end_excerpt_id) in ranges {
2705            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2706                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2707                    continue;
2708                }
2709                if last_hunk_row.map_or(false, |row| row >= diff_hunk.row_range.start) {
2710                    continue;
2711                }
2712                let start = Anchor::in_buffer(
2713                    diff_hunk.excerpt_id,
2714                    diff_hunk.buffer_id,
2715                    diff_hunk.buffer_range.start,
2716                );
2717                let end = Anchor::in_buffer(
2718                    diff_hunk.excerpt_id,
2719                    diff_hunk.buffer_id,
2720                    diff_hunk.buffer_range.end,
2721                );
2722                let start = snapshot.excerpt_offset_for_anchor(&start);
2723                let end = snapshot.excerpt_offset_for_anchor(&end);
2724                last_hunk_row = Some(diff_hunk.row_range.start);
2725                excerpt_edits.push(text::Edit {
2726                    old: start..end,
2727                    new: start..end,
2728                });
2729            }
2730        }
2731
2732        self.sync_diff_transforms(
2733            &mut snapshot,
2734            excerpt_edits,
2735            DiffChangeKind::ExpandOrCollapseHunks { expand },
2736        );
2737        cx.emit(Event::DiffHunksToggled);
2738        cx.emit(Event::Edited {
2739            singleton_buffer_edited: false,
2740            edited_buffer: None,
2741        });
2742    }
2743
2744    pub fn expand_or_collapse_diff_hunks(
2745        &mut self,
2746        ranges: Vec<Range<Anchor>>,
2747        expand: bool,
2748        cx: &mut Context<Self>,
2749    ) {
2750        let snapshot = self.snapshot.borrow().clone();
2751        let ranges = ranges.iter().map(move |range| {
2752            let end_excerpt_id = range.end.excerpt_id;
2753            let range = range.to_point(&snapshot);
2754            let mut peek_end = range.end;
2755            if range.end.row < snapshot.max_row().0 {
2756                peek_end = Point::new(range.end.row + 1, 0);
2757            };
2758            (range.start..peek_end, end_excerpt_id)
2759        });
2760        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2761    }
2762
2763    pub fn resize_excerpt(
2764        &mut self,
2765        id: ExcerptId,
2766        range: Range<text::Anchor>,
2767        cx: &mut Context<Self>,
2768    ) {
2769        self.sync(cx);
2770
2771        let mut snapshot = self.snapshot.borrow_mut();
2772        let locator = snapshot.excerpt_locator_for_id(id);
2773        let mut new_excerpts = SumTree::default();
2774        let mut cursor = snapshot
2775            .excerpts
2776            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2777        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2778
2779        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2780        new_excerpts.append(prefix, &());
2781
2782        let mut excerpt = cursor.item().unwrap().clone();
2783        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2784
2785        excerpt.range.context.start = range.start;
2786        excerpt.range.context.end = range.end;
2787        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2788
2789        excerpt.text_summary = excerpt
2790            .buffer
2791            .text_summary_for_range(excerpt.range.context.clone());
2792
2793        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2794        let old_start_offset = cursor.start().1;
2795        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2796        let edit = Edit {
2797            old: old_start_offset..old_start_offset + old_text_len,
2798            new: new_start_offset..new_start_offset + new_text_len,
2799        };
2800
2801        if let Some(last_edit) = edits.last_mut() {
2802            if last_edit.old.end == edit.old.start {
2803                last_edit.old.end = edit.old.end;
2804                last_edit.new.end = edit.new.end;
2805            } else {
2806                edits.push(edit);
2807            }
2808        } else {
2809            edits.push(edit);
2810        }
2811
2812        new_excerpts.push(excerpt, &());
2813
2814        cursor.next(&());
2815
2816        new_excerpts.append(cursor.suffix(&()), &());
2817
2818        drop(cursor);
2819        snapshot.excerpts = new_excerpts;
2820
2821        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2822        cx.emit(Event::Edited {
2823            singleton_buffer_edited: false,
2824            edited_buffer: None,
2825        });
2826        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2827        cx.notify();
2828    }
2829
2830    pub fn expand_excerpts(
2831        &mut self,
2832        ids: impl IntoIterator<Item = ExcerptId>,
2833        line_count: u32,
2834        direction: ExpandExcerptDirection,
2835        cx: &mut Context<Self>,
2836    ) {
2837        if line_count == 0 {
2838            return;
2839        }
2840        self.sync(cx);
2841        if !self.excerpts_by_path.is_empty() {
2842            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2843            return;
2844        }
2845        let mut snapshot = self.snapshot.borrow_mut();
2846
2847        let ids = ids.into_iter().collect::<Vec<_>>();
2848        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2849        let mut new_excerpts = SumTree::default();
2850        let mut cursor = snapshot
2851            .excerpts
2852            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2853        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2854
2855        for locator in &locators {
2856            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2857            new_excerpts.append(prefix, &());
2858
2859            let mut excerpt = cursor.item().unwrap().clone();
2860            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2861
2862            let up_line_count = if direction.should_expand_up() {
2863                line_count
2864            } else {
2865                0
2866            };
2867
2868            let start_row = excerpt
2869                .range
2870                .context
2871                .start
2872                .to_point(&excerpt.buffer)
2873                .row
2874                .saturating_sub(up_line_count);
2875            let start_point = Point::new(start_row, 0);
2876            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2877
2878            let down_line_count = if direction.should_expand_down() {
2879                line_count
2880            } else {
2881                0
2882            };
2883
2884            let mut end_point = excerpt.buffer.clip_point(
2885                excerpt.range.context.end.to_point(&excerpt.buffer)
2886                    + Point::new(down_line_count, 0),
2887                Bias::Left,
2888            );
2889            end_point.column = excerpt.buffer.line_len(end_point.row);
2890            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2891            excerpt.max_buffer_row = end_point.row;
2892
2893            excerpt.text_summary = excerpt
2894                .buffer
2895                .text_summary_for_range(excerpt.range.context.clone());
2896
2897            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2898            let old_start_offset = cursor.start().1;
2899            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2900            let edit = Edit {
2901                old: old_start_offset..old_start_offset + old_text_len,
2902                new: new_start_offset..new_start_offset + new_text_len,
2903            };
2904
2905            if let Some(last_edit) = edits.last_mut() {
2906                if last_edit.old.end == edit.old.start {
2907                    last_edit.old.end = edit.old.end;
2908                    last_edit.new.end = edit.new.end;
2909                } else {
2910                    edits.push(edit);
2911                }
2912            } else {
2913                edits.push(edit);
2914            }
2915
2916            new_excerpts.push(excerpt, &());
2917
2918            cursor.next(&());
2919        }
2920
2921        new_excerpts.append(cursor.suffix(&()), &());
2922
2923        drop(cursor);
2924        snapshot.excerpts = new_excerpts;
2925
2926        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2927        cx.emit(Event::Edited {
2928            singleton_buffer_edited: false,
2929            edited_buffer: None,
2930        });
2931        cx.emit(Event::ExcerptsExpanded { ids });
2932        cx.notify();
2933    }
2934
2935    fn sync(&self, cx: &App) {
2936        let changed = self.buffer_changed_since_sync.replace(false);
2937        if !changed {
2938            return;
2939        }
2940
2941        let mut snapshot = self.snapshot.borrow_mut();
2942        let mut excerpts_to_edit = Vec::new();
2943        let mut non_text_state_updated = false;
2944        let mut is_dirty = false;
2945        let mut has_deleted_file = false;
2946        let mut has_conflict = false;
2947        let mut edited = false;
2948        let mut buffers = self.buffers.borrow_mut();
2949        for buffer_state in buffers.values_mut() {
2950            let buffer = buffer_state.buffer.read(cx);
2951            let version = buffer.version();
2952            let non_text_state_update_count = buffer.non_text_state_update_count();
2953
2954            let buffer_edited = version.changed_since(&buffer_state.last_version);
2955            let buffer_non_text_state_updated =
2956                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2957            if buffer_edited || buffer_non_text_state_updated {
2958                buffer_state.last_version = version;
2959                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2960                excerpts_to_edit.extend(
2961                    buffer_state
2962                        .excerpts
2963                        .iter()
2964                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2965                );
2966            }
2967
2968            edited |= buffer_edited;
2969            non_text_state_updated |= buffer_non_text_state_updated;
2970            is_dirty |= buffer.is_dirty();
2971            has_deleted_file |= buffer
2972                .file()
2973                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2974            has_conflict |= buffer.has_conflict();
2975        }
2976        if edited {
2977            snapshot.edit_count += 1;
2978        }
2979        if non_text_state_updated {
2980            snapshot.non_text_state_update_count += 1;
2981        }
2982        snapshot.is_dirty = is_dirty;
2983        snapshot.has_deleted_file = has_deleted_file;
2984        snapshot.has_conflict = has_conflict;
2985
2986        for (id, diff) in self.diffs.iter() {
2987            if snapshot.diffs.get(&id).is_none() {
2988                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2989            }
2990        }
2991
2992        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2993
2994        let mut edits = Vec::new();
2995        let mut new_excerpts = SumTree::default();
2996        let mut cursor = snapshot
2997            .excerpts
2998            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2999
3000        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3001            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
3002            let old_excerpt = cursor.item().unwrap();
3003            let buffer = buffer.read(cx);
3004            let buffer_id = buffer.remote_id();
3005
3006            let mut new_excerpt;
3007            if buffer_edited {
3008                edits.extend(
3009                    buffer
3010                        .edits_since_in_range::<usize>(
3011                            old_excerpt.buffer.version(),
3012                            old_excerpt.range.context.clone(),
3013                        )
3014                        .map(|edit| {
3015                            let excerpt_old_start = cursor.start().1;
3016                            let excerpt_new_start =
3017                                ExcerptOffset::new(new_excerpts.summary().text.len);
3018                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3019                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3020                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3021                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3022                            Edit {
3023                                old: old_start..old_end,
3024                                new: new_start..new_end,
3025                            }
3026                        }),
3027                );
3028
3029                new_excerpt = Excerpt::new(
3030                    old_excerpt.id,
3031                    locator.clone(),
3032                    buffer_id,
3033                    buffer.snapshot(),
3034                    old_excerpt.range.clone(),
3035                    old_excerpt.has_trailing_newline,
3036                );
3037            } else {
3038                new_excerpt = old_excerpt.clone();
3039                new_excerpt.buffer = buffer.snapshot();
3040            }
3041
3042            new_excerpts.push(new_excerpt, &());
3043            cursor.next(&());
3044        }
3045        new_excerpts.append(cursor.suffix(&()), &());
3046
3047        drop(cursor);
3048        snapshot.excerpts = new_excerpts;
3049
3050        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3051    }
3052
3053    fn sync_diff_transforms(
3054        &self,
3055        snapshot: &mut MultiBufferSnapshot,
3056        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3057        change_kind: DiffChangeKind,
3058    ) {
3059        if excerpt_edits.is_empty() {
3060            return;
3061        }
3062
3063        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3064        let mut old_diff_transforms = snapshot
3065            .diff_transforms
3066            .cursor::<(ExcerptOffset, usize)>(&());
3067        let mut new_diff_transforms = SumTree::default();
3068        let mut old_expanded_hunks = HashSet::default();
3069        let mut output_edits = Vec::new();
3070        let mut output_delta = 0_isize;
3071        let mut at_transform_boundary = true;
3072        let mut end_of_current_insert = None;
3073
3074        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3075        while let Some(edit) = excerpt_edits.next() {
3076            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
3077            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3078                excerpts.prev(&());
3079            }
3080
3081            // Keep any transforms that are before the edit.
3082            if at_transform_boundary {
3083                at_transform_boundary = false;
3084                let transforms_before_edit =
3085                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3086                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3087                if let Some(transform) = old_diff_transforms.item() {
3088                    if old_diff_transforms.end(&()).0 == edit.old.start
3089                        && old_diff_transforms.start().0 < edit.old.start
3090                    {
3091                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3092                        old_diff_transforms.next(&());
3093                    }
3094                }
3095            }
3096
3097            // Compute the start of the edit in output coordinates.
3098            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3099            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3100            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3101
3102            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3103                &edit,
3104                &mut excerpts,
3105                &mut old_diff_transforms,
3106                &mut new_diff_transforms,
3107                &mut end_of_current_insert,
3108                &mut old_expanded_hunks,
3109                &snapshot,
3110                change_kind,
3111            );
3112
3113            // Compute the end of the edit in output coordinates.
3114            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3115            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3116            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3117            let edit_new_end =
3118                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3119            let output_edit = Edit {
3120                old: edit_old_start..edit_old_end,
3121                new: edit_new_start..edit_new_end,
3122            };
3123
3124            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3125            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3126            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3127                output_edits.push(output_edit);
3128            }
3129
3130            // If this is the last edit that intersects the current diff transform,
3131            // then recreate the content up to the end of this transform, to prepare
3132            // for reusing additional slices of the old transforms.
3133            if excerpt_edits.peek().map_or(true, |next_edit| {
3134                next_edit.old.start >= old_diff_transforms.end(&()).0
3135            }) {
3136                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3137                    && match old_diff_transforms.item() {
3138                        Some(DiffTransform::BufferContent {
3139                            inserted_hunk_info: Some(hunk),
3140                            ..
3141                        }) => excerpts.item().is_some_and(|excerpt| {
3142                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3143                        }),
3144                        _ => true,
3145                    };
3146
3147                let mut excerpt_offset = edit.new.end;
3148                if !keep_next_old_transform {
3149                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3150                    old_diff_transforms.next(&());
3151                }
3152
3153                old_expanded_hunks.clear();
3154                self.push_buffer_content_transform(
3155                    &snapshot,
3156                    &mut new_diff_transforms,
3157                    excerpt_offset,
3158                    end_of_current_insert,
3159                );
3160                at_transform_boundary = true;
3161            }
3162        }
3163
3164        // Keep any transforms that are after the last edit.
3165        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3166
3167        // Ensure there's always at least one buffer content transform.
3168        if new_diff_transforms.is_empty() {
3169            new_diff_transforms.push(
3170                DiffTransform::BufferContent {
3171                    summary: Default::default(),
3172                    inserted_hunk_info: None,
3173                },
3174                &(),
3175            );
3176        }
3177
3178        self.subscriptions.publish(output_edits);
3179        drop(old_diff_transforms);
3180        drop(excerpts);
3181        snapshot.diff_transforms = new_diff_transforms;
3182        snapshot.edit_count += 1;
3183
3184        #[cfg(any(test, feature = "test-support"))]
3185        snapshot.check_invariants();
3186    }
3187
3188    fn recompute_diff_transforms_for_edit(
3189        &self,
3190        edit: &Edit<TypedOffset<Excerpt>>,
3191        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3192        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3193        new_diff_transforms: &mut SumTree<DiffTransform>,
3194        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3195        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3196        snapshot: &MultiBufferSnapshot,
3197        change_kind: DiffChangeKind,
3198    ) -> bool {
3199        log::trace!(
3200            "recomputing diff transform for edit {:?} => {:?}",
3201            edit.old.start.value..edit.old.end.value,
3202            edit.new.start.value..edit.new.end.value
3203        );
3204
3205        // Record which hunks were previously expanded.
3206        while let Some(item) = old_diff_transforms.item() {
3207            if let Some(hunk_info) = item.hunk_info() {
3208                log::trace!(
3209                    "previously expanded hunk at {}",
3210                    old_diff_transforms.start().0
3211                );
3212                old_expanded_hunks.insert(hunk_info);
3213            }
3214            if old_diff_transforms.end(&()).0 > edit.old.end {
3215                break;
3216            }
3217            old_diff_transforms.next(&());
3218        }
3219
3220        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3221        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3222        if old_expanded_hunks.is_empty()
3223            && change_kind == DiffChangeKind::BufferEdited
3224            && !all_diff_hunks_expanded
3225        {
3226            return false;
3227        }
3228
3229        // Visit each excerpt that intersects the edit.
3230        let mut did_expand_hunks = false;
3231        while let Some(excerpt) = excerpts.item() {
3232            // Recompute the expanded hunks in the portion of the excerpt that
3233            // intersects the edit.
3234            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3235                let buffer = &excerpt.buffer;
3236                let excerpt_start = *excerpts.start();
3237                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3238                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3239                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3240                let edit_buffer_start =
3241                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3242                let edit_buffer_end =
3243                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3244                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3245                let edit_anchor_range =
3246                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3247
3248                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3249                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3250                        continue;
3251                    }
3252
3253                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3254                    if hunk_buffer_range.start < excerpt_buffer_start {
3255                        log::trace!("skipping hunk that starts before excerpt");
3256                        continue;
3257                    }
3258
3259                    let hunk_info = DiffTransformHunkInfo {
3260                        excerpt_id: excerpt.id,
3261                        hunk_start_anchor: hunk.buffer_range.start,
3262                        hunk_secondary_status: hunk.secondary_status,
3263                    };
3264
3265                    let hunk_excerpt_start = excerpt_start
3266                        + ExcerptOffset::new(
3267                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3268                        );
3269                    let hunk_excerpt_end = excerpt_end.min(
3270                        excerpt_start
3271                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3272                    );
3273
3274                    self.push_buffer_content_transform(
3275                        snapshot,
3276                        new_diff_transforms,
3277                        hunk_excerpt_start,
3278                        *end_of_current_insert,
3279                    );
3280
3281                    // For every existing hunk, determine if it was previously expanded
3282                    // and if it should currently be expanded.
3283                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3284                    let should_expand_hunk = match &change_kind {
3285                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3286                            was_previously_expanded || all_diff_hunks_expanded
3287                        }
3288                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3289                            let intersects = hunk_buffer_range.is_empty()
3290                                || hunk_buffer_range.end > edit_buffer_start;
3291                            if *expand {
3292                                intersects || was_previously_expanded || all_diff_hunks_expanded
3293                            } else {
3294                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3295                            }
3296                        }
3297                        _ => was_previously_expanded || all_diff_hunks_expanded,
3298                    };
3299
3300                    if should_expand_hunk {
3301                        did_expand_hunks = true;
3302                        log::trace!(
3303                            "expanding hunk {:?}, excerpt:{:?}",
3304                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3305                            excerpt.id
3306                        );
3307
3308                        if !hunk.diff_base_byte_range.is_empty()
3309                            && hunk_buffer_range.start >= edit_buffer_start
3310                            && hunk_buffer_range.start <= excerpt_buffer_end
3311                        {
3312                            let base_text = diff.base_text();
3313                            let mut text_cursor =
3314                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3315                            let mut base_text_summary =
3316                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3317
3318                            let mut has_trailing_newline = false;
3319                            if base_text_summary.last_line_chars > 0 {
3320                                base_text_summary += TextSummary::newline();
3321                                has_trailing_newline = true;
3322                            }
3323
3324                            new_diff_transforms.push(
3325                                DiffTransform::DeletedHunk {
3326                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3327                                    summary: base_text_summary,
3328                                    buffer_id: excerpt.buffer_id,
3329                                    hunk_info,
3330                                    has_trailing_newline,
3331                                },
3332                                &(),
3333                            );
3334                        }
3335
3336                        if !hunk_buffer_range.is_empty() {
3337                            *end_of_current_insert =
3338                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3339                        }
3340                    }
3341                }
3342            }
3343
3344            if excerpts.end(&()) <= edit.new.end {
3345                excerpts.next(&());
3346            } else {
3347                break;
3348            }
3349        }
3350
3351        did_expand_hunks || !old_expanded_hunks.is_empty()
3352    }
3353
3354    fn append_diff_transforms(
3355        &self,
3356        new_transforms: &mut SumTree<DiffTransform>,
3357        subtree: SumTree<DiffTransform>,
3358    ) {
3359        if let Some(DiffTransform::BufferContent {
3360            inserted_hunk_info,
3361            summary,
3362        }) = subtree.first()
3363        {
3364            if self.extend_last_buffer_content_transform(
3365                new_transforms,
3366                *inserted_hunk_info,
3367                *summary,
3368            ) {
3369                let mut cursor = subtree.cursor::<()>(&());
3370                cursor.next(&());
3371                cursor.next(&());
3372                new_transforms.append(cursor.suffix(&()), &());
3373                return;
3374            }
3375        }
3376        new_transforms.append(subtree, &());
3377    }
3378
3379    fn push_diff_transform(
3380        &self,
3381        new_transforms: &mut SumTree<DiffTransform>,
3382        transform: DiffTransform,
3383    ) {
3384        if let DiffTransform::BufferContent {
3385            inserted_hunk_info: inserted_hunk_anchor,
3386            summary,
3387        } = transform
3388        {
3389            if self.extend_last_buffer_content_transform(
3390                new_transforms,
3391                inserted_hunk_anchor,
3392                summary,
3393            ) {
3394                return;
3395            }
3396        }
3397        new_transforms.push(transform, &());
3398    }
3399
3400    fn push_buffer_content_transform(
3401        &self,
3402        old_snapshot: &MultiBufferSnapshot,
3403        new_transforms: &mut SumTree<DiffTransform>,
3404        end_offset: ExcerptOffset,
3405        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3406    ) {
3407        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3408            (end_offset.min(insertion_end_offset), Some(hunk_info))
3409        });
3410        let unchanged_region = [(end_offset, None)];
3411
3412        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3413        {
3414            let start_offset = new_transforms.summary().excerpt_len();
3415            if end_offset <= start_offset {
3416                continue;
3417            }
3418            let summary_to_add = old_snapshot
3419                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3420
3421            if !self.extend_last_buffer_content_transform(
3422                new_transforms,
3423                inserted_hunk_info,
3424                summary_to_add,
3425            ) {
3426                new_transforms.push(
3427                    DiffTransform::BufferContent {
3428                        summary: summary_to_add,
3429                        inserted_hunk_info,
3430                    },
3431                    &(),
3432                )
3433            }
3434        }
3435    }
3436
3437    fn extend_last_buffer_content_transform(
3438        &self,
3439        new_transforms: &mut SumTree<DiffTransform>,
3440        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3441        summary_to_add: TextSummary,
3442    ) -> bool {
3443        let mut did_extend = false;
3444        new_transforms.update_last(
3445            |last_transform| {
3446                if let DiffTransform::BufferContent {
3447                    summary,
3448                    inserted_hunk_info: inserted_hunk_anchor,
3449                } = last_transform
3450                {
3451                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3452                        *summary += summary_to_add;
3453                        did_extend = true;
3454                    }
3455                }
3456            },
3457            &(),
3458        );
3459        did_extend
3460    }
3461}
3462
3463fn build_excerpt_ranges(
3464    ranges: impl IntoIterator<Item = Range<Point>>,
3465    context_line_count: u32,
3466    buffer_snapshot: &BufferSnapshot,
3467) -> Vec<ExcerptRange<Point>> {
3468    ranges
3469        .into_iter()
3470        .map(|range| {
3471            let start_row = range.start.row.saturating_sub(context_line_count);
3472            let start = Point::new(start_row, 0);
3473            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3474            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3475            ExcerptRange {
3476                context: start..end,
3477                primary: range,
3478            }
3479        })
3480        .collect()
3481}
3482
3483#[cfg(any(test, feature = "test-support"))]
3484impl MultiBuffer {
3485    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3486        let buffer = cx.new(|cx| Buffer::local(text, cx));
3487        cx.new(|cx| Self::singleton(buffer, cx))
3488    }
3489
3490    pub fn build_multi<const COUNT: usize>(
3491        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3492        cx: &mut gpui::App,
3493    ) -> Entity<Self> {
3494        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3495        for (text, ranges) in excerpts {
3496            let buffer = cx.new(|cx| Buffer::local(text, cx));
3497            let excerpt_ranges = ranges
3498                .into_iter()
3499                .map(|range| ExcerptRange::new(range.clone()));
3500            multi.update(cx, |multi, cx| {
3501                multi.push_excerpts(buffer, excerpt_ranges, cx)
3502            });
3503        }
3504
3505        multi
3506    }
3507
3508    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3509        cx.new(|cx| Self::singleton(buffer, cx))
3510    }
3511
3512    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3513        cx.new(|cx| {
3514            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3515            let mutation_count = rng.gen_range(1..=5);
3516            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3517            multibuffer
3518        })
3519    }
3520
3521    pub fn randomly_edit(
3522        &mut self,
3523        rng: &mut impl rand::Rng,
3524        edit_count: usize,
3525        cx: &mut Context<Self>,
3526    ) {
3527        use util::RandomCharIter;
3528
3529        let snapshot = self.read(cx);
3530        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3531        let mut last_end = None;
3532        for _ in 0..edit_count {
3533            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3534                break;
3535            }
3536
3537            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3538            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3539            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3540            last_end = Some(end);
3541
3542            let mut range = start..end;
3543            if rng.gen_bool(0.2) {
3544                mem::swap(&mut range.start, &mut range.end);
3545            }
3546
3547            let new_text_len = rng.gen_range(0..10);
3548            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3549
3550            edits.push((range, new_text.into()));
3551        }
3552        log::info!("mutating multi-buffer with {:?}", edits);
3553        drop(snapshot);
3554
3555        self.edit(edits, None, cx);
3556    }
3557
3558    pub fn randomly_edit_excerpts(
3559        &mut self,
3560        rng: &mut impl rand::Rng,
3561        mutation_count: usize,
3562        cx: &mut Context<Self>,
3563    ) {
3564        use rand::prelude::*;
3565        use std::env;
3566        use util::RandomCharIter;
3567
3568        let max_excerpts = env::var("MAX_EXCERPTS")
3569            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3570            .unwrap_or(5);
3571
3572        let mut buffers = Vec::new();
3573        for _ in 0..mutation_count {
3574            if rng.gen_bool(0.05) {
3575                log::info!("Clearing multi-buffer");
3576                self.clear(cx);
3577                continue;
3578            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3579                let ids = self.excerpt_ids();
3580                let mut excerpts = HashSet::default();
3581                for _ in 0..rng.gen_range(0..ids.len()) {
3582                    excerpts.extend(ids.choose(rng).copied());
3583                }
3584
3585                let line_count = rng.gen_range(0..5);
3586
3587                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3588
3589                self.expand_excerpts(
3590                    excerpts.iter().cloned(),
3591                    line_count,
3592                    ExpandExcerptDirection::UpAndDown,
3593                    cx,
3594                );
3595                continue;
3596            }
3597
3598            let excerpt_ids = self.excerpt_ids();
3599            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3600                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3601                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3602                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3603                    let buffer = buffers.last().unwrap().read(cx);
3604                    log::info!(
3605                        "Creating new buffer {} with text: {:?}",
3606                        buffer.remote_id(),
3607                        buffer.text()
3608                    );
3609                    buffers.last().unwrap().clone()
3610                } else {
3611                    self.buffers
3612                        .borrow()
3613                        .values()
3614                        .choose(rng)
3615                        .unwrap()
3616                        .buffer
3617                        .clone()
3618                };
3619
3620                let buffer = buffer_handle.read(cx);
3621                let buffer_text = buffer.text();
3622                let ranges = (0..rng.gen_range(0..5))
3623                    .map(|_| {
3624                        let end_ix =
3625                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3626                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3627                        ExcerptRange::new(start_ix..end_ix)
3628                    })
3629                    .collect::<Vec<_>>();
3630                log::info!(
3631                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3632                    buffer_handle.read(cx).remote_id(),
3633                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3634                    ranges
3635                        .iter()
3636                        .map(|r| &buffer_text[r.context.clone()])
3637                        .collect::<Vec<_>>()
3638                );
3639
3640                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3641                log::info!("Inserted with ids: {:?}", excerpt_id);
3642            } else {
3643                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3644                let mut excerpts_to_remove = excerpt_ids
3645                    .choose_multiple(rng, remove_count)
3646                    .cloned()
3647                    .collect::<Vec<_>>();
3648                let snapshot = self.snapshot.borrow();
3649                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3650                drop(snapshot);
3651                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3652                self.remove_excerpts(excerpts_to_remove, cx);
3653            }
3654        }
3655    }
3656
3657    pub fn randomly_mutate(
3658        &mut self,
3659        rng: &mut impl rand::Rng,
3660        mutation_count: usize,
3661        cx: &mut Context<Self>,
3662    ) {
3663        use rand::prelude::*;
3664
3665        if rng.gen_bool(0.7) || self.singleton {
3666            let buffer = self
3667                .buffers
3668                .borrow()
3669                .values()
3670                .choose(rng)
3671                .map(|state| state.buffer.clone());
3672
3673            if let Some(buffer) = buffer {
3674                buffer.update(cx, |buffer, cx| {
3675                    if rng.r#gen() {
3676                        buffer.randomly_edit(rng, mutation_count, cx);
3677                    } else {
3678                        buffer.randomly_undo_redo(rng, cx);
3679                    }
3680                });
3681            } else {
3682                self.randomly_edit(rng, mutation_count, cx);
3683            }
3684        } else {
3685            self.randomly_edit_excerpts(rng, mutation_count, cx);
3686        }
3687
3688        self.check_invariants(cx);
3689    }
3690
3691    fn check_invariants(&self, cx: &App) {
3692        self.read(cx).check_invariants();
3693    }
3694}
3695
3696impl EventEmitter<Event> for MultiBuffer {}
3697
3698impl MultiBufferSnapshot {
3699    pub fn text(&self) -> String {
3700        self.chunks(0..self.len(), false)
3701            .map(|chunk| chunk.text)
3702            .collect()
3703    }
3704
3705    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3706        self.reversed_chunks_in_range(0..position.to_offset(self))
3707            .flat_map(|c| c.chars().rev())
3708    }
3709
3710    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3711        let mut cursor = self.cursor::<usize>();
3712        cursor.seek(&range.end);
3713        let current_chunks = cursor.region().as_ref().map(|region| {
3714            let start_overshoot = range.start.saturating_sub(region.range.start);
3715            let end_overshoot = range.end - region.range.start;
3716            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3717            let start = region.buffer_range.start + start_overshoot;
3718            region.buffer.reversed_chunks_in_range(start..end)
3719        });
3720        ReversedMultiBufferChunks {
3721            cursor,
3722            current_chunks,
3723            start: range.start,
3724            offset: range.end,
3725        }
3726    }
3727
3728    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3729        let offset = position.to_offset(self);
3730        self.text_for_range(offset..self.len())
3731            .flat_map(|chunk| chunk.chars())
3732    }
3733
3734    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3735        self.chunks(range, false).map(|chunk| chunk.text)
3736    }
3737
3738    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3739        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3740            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3741    }
3742
3743    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3744    where
3745        T: ToOffset,
3746    {
3747        let position = position.to_offset(self);
3748        position == self.clip_offset(position, Bias::Left)
3749            && self
3750                .bytes_in_range(position..self.len())
3751                .flatten()
3752                .copied()
3753                .take(needle.len())
3754                .eq(needle.bytes())
3755    }
3756
3757    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3758        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3759    }
3760
3761    pub fn diff_hunks_in_range<T: ToPoint>(
3762        &self,
3763        range: Range<T>,
3764    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3765        let query_range = range.start.to_point(self)..range.end.to_point(self);
3766        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3767            let diff = self.diffs.get(&buffer.remote_id())?;
3768            let buffer_start = buffer.anchor_before(buffer_range.start);
3769            let buffer_end = buffer.anchor_after(buffer_range.end);
3770            Some(
3771                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3772                    .filter_map(|hunk| {
3773                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3774                            return None;
3775                        }
3776                        Some((hunk.range.clone(), hunk))
3777                    }),
3778            )
3779        })
3780        .filter_map(move |(range, hunk, excerpt)| {
3781            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3782            {
3783                return None;
3784            }
3785            let end_row = if range.end.column == 0 {
3786                range.end.row
3787            } else {
3788                range.end.row + 1
3789            };
3790            Some(MultiBufferDiffHunk {
3791                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3792                buffer_id: excerpt.buffer_id,
3793                excerpt_id: excerpt.id,
3794                buffer_range: hunk.buffer_range.clone(),
3795                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3796                secondary_status: hunk.secondary_status,
3797            })
3798        })
3799    }
3800
3801    pub fn excerpt_ids_for_range<T: ToOffset>(
3802        &self,
3803        range: Range<T>,
3804    ) -> impl Iterator<Item = ExcerptId> + '_ {
3805        let range = range.start.to_offset(self)..range.end.to_offset(self);
3806        let mut cursor = self.cursor::<usize>();
3807        cursor.seek(&range.start);
3808        std::iter::from_fn(move || {
3809            let region = cursor.region()?;
3810            if region.range.start >= range.end {
3811                return None;
3812            }
3813            cursor.next_excerpt();
3814            Some(region.excerpt.id)
3815        })
3816    }
3817
3818    pub fn buffer_ids_for_range<T: ToOffset>(
3819        &self,
3820        range: Range<T>,
3821    ) -> impl Iterator<Item = BufferId> + '_ {
3822        let range = range.start.to_offset(self)..range.end.to_offset(self);
3823        let mut cursor = self.cursor::<usize>();
3824        cursor.seek(&range.start);
3825        std::iter::from_fn(move || {
3826            let region = cursor.region()?;
3827            if region.range.start > range.end
3828                || region.range.start == range.end && region.range.start > range.start
3829            {
3830                return None;
3831            }
3832            cursor.next_excerpt();
3833            Some(region.excerpt.buffer_id)
3834        })
3835    }
3836
3837    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3838        &self,
3839        ranges: impl Iterator<Item = Range<T>>,
3840    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3841        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3842    }
3843
3844    pub fn range_to_buffer_ranges<T: ToOffset>(
3845        &self,
3846        range: Range<T>,
3847    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3848        let start = range.start.to_offset(&self);
3849        let end = range.end.to_offset(&self);
3850
3851        let mut cursor = self.cursor::<usize>();
3852        cursor.seek(&start);
3853
3854        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3855        while let Some(region) = cursor.region() {
3856            if region.range.start > end {
3857                break;
3858            }
3859            if region.is_main_buffer {
3860                let start_overshoot = start.saturating_sub(region.range.start);
3861                let end_overshoot = end.saturating_sub(region.range.start);
3862                let start = region
3863                    .buffer_range
3864                    .end
3865                    .min(region.buffer_range.start + start_overshoot);
3866                let end = region
3867                    .buffer_range
3868                    .end
3869                    .min(region.buffer_range.start + end_overshoot);
3870                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3871                    *excerpt_id == region.excerpt.id && prev_range.end == start
3872                }) {
3873                    prev.1.end = end;
3874                } else {
3875                    result.push((region.buffer, start..end, region.excerpt.id));
3876                }
3877            }
3878            cursor.next();
3879        }
3880        result
3881    }
3882
3883    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3884        &self,
3885        range: Range<T>,
3886    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3887        let start = range.start.to_offset(&self);
3888        let end = range.end.to_offset(&self);
3889
3890        let mut cursor = self.cursor::<usize>();
3891        cursor.seek(&start);
3892
3893        std::iter::from_fn(move || {
3894            let region = cursor.region()?;
3895            if region.range.start > end {
3896                return None;
3897            }
3898            let start_overshoot = start.saturating_sub(region.range.start);
3899            let end_overshoot = end.saturating_sub(region.range.start);
3900            let start = region
3901                .buffer_range
3902                .end
3903                .min(region.buffer_range.start + start_overshoot);
3904            let end = region
3905                .buffer_range
3906                .end
3907                .min(region.buffer_range.start + end_overshoot);
3908
3909            let region_excerpt_id = region.excerpt.id;
3910            let deleted_hunk_anchor = if region.is_main_buffer {
3911                None
3912            } else {
3913                Some(self.anchor_before(region.range.start))
3914            };
3915            let result = (
3916                region.buffer,
3917                start..end,
3918                region_excerpt_id,
3919                deleted_hunk_anchor,
3920            );
3921            cursor.next();
3922            Some(result)
3923        })
3924    }
3925
3926    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3927    /// coordinates.
3928    ///
3929    /// The given callback will be called for every excerpt intersecting the given range. It will
3930    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3931    /// The callback should return an iterator of metadata items from that buffer, each paired
3932    /// with a buffer range.
3933    ///
3934    /// The returned iterator yields each of these metadata items, paired with its range in
3935    /// multi-buffer coordinates.
3936    fn lift_buffer_metadata<'a, D, M, I>(
3937        &'a self,
3938        query_range: Range<D>,
3939        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3940    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3941    where
3942        I: Iterator<Item = (Range<D>, M)> + 'a,
3943        D: TextDimension + Ord + Sub<D, Output = D>,
3944    {
3945        let max_position = D::from_text_summary(&self.text_summary());
3946        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3947        let mut cursor = self.cursor::<D>();
3948
3949        // Find the excerpt and buffer offset where the given range ends.
3950        cursor.seek(&query_range.end);
3951        let mut range_end = None;
3952        while let Some(region) = cursor.region() {
3953            if region.is_main_buffer {
3954                let mut buffer_end = region.buffer_range.start;
3955                let overshoot = if query_range.end > region.range.start {
3956                    query_range.end - region.range.start
3957                } else {
3958                    D::default()
3959                };
3960                buffer_end.add_assign(&overshoot);
3961                range_end = Some((region.excerpt.id, buffer_end));
3962                break;
3963            }
3964            cursor.next();
3965        }
3966
3967        cursor.seek(&query_range.start);
3968
3969        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3970            if region.range.start > D::zero(&()) {
3971                cursor.prev()
3972            }
3973        }
3974
3975        iter::from_fn(move || {
3976            loop {
3977                let excerpt = cursor.excerpt()?;
3978
3979                // If we have already retrieved metadata for this excerpt, continue to use it.
3980                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3981                    .as_mut()
3982                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3983                {
3984                    Some(metadata)
3985                }
3986                // Otherwise, compute the intersection of the input range with the excerpt's range,
3987                // and retrieve the metadata for the resulting range.
3988                else {
3989                    let region = cursor.region()?;
3990                    let mut buffer_start;
3991                    if region.is_main_buffer {
3992                        buffer_start = region.buffer_range.start;
3993                        if query_range.start > region.range.start {
3994                            let overshoot = query_range.start - region.range.start;
3995                            buffer_start.add_assign(&overshoot);
3996                        }
3997                        buffer_start = buffer_start.min(region.buffer_range.end);
3998                    } else {
3999                        buffer_start = cursor.main_buffer_position()?;
4000                    };
4001                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4002                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
4003                        if excerpt.id == end_excerpt_id {
4004                            buffer_end = buffer_end.min(end_buffer_offset);
4005                        }
4006                    }
4007
4008                    if let Some(iterator) =
4009                        get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
4010                    {
4011                        Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
4012                    } else {
4013                        None
4014                    }
4015                };
4016
4017                // Visit each metadata item.
4018                if let Some((metadata_buffer_range, metadata)) =
4019                    metadata_iter.and_then(Iterator::next)
4020                {
4021                    // Find the multibuffer regions that contain the start and end of
4022                    // the metadata item's range.
4023                    if metadata_buffer_range.start > D::default() {
4024                        while let Some(region) = cursor.region() {
4025                            if region.is_main_buffer
4026                                && (region.buffer_range.end >= metadata_buffer_range.start
4027                                    || cursor.is_at_end_of_excerpt())
4028                            {
4029                                break;
4030                            }
4031                            cursor.next();
4032                        }
4033                    }
4034                    let start_region = cursor.region()?;
4035                    while let Some(region) = cursor.region() {
4036                        if region.is_main_buffer
4037                            && (region.buffer_range.end > metadata_buffer_range.end
4038                                || cursor.is_at_end_of_excerpt())
4039                        {
4040                            break;
4041                        }
4042                        cursor.next();
4043                    }
4044                    let end_region = cursor.region();
4045
4046                    // Convert the metadata item's range into multibuffer coordinates.
4047                    let mut start_position = start_region.range.start;
4048                    let region_buffer_start = start_region.buffer_range.start;
4049                    if start_region.is_main_buffer
4050                        && metadata_buffer_range.start > region_buffer_start
4051                    {
4052                        start_position
4053                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4054                        start_position = start_position.min(start_region.range.end);
4055                    }
4056
4057                    let mut end_position = max_position;
4058                    if let Some(end_region) = &end_region {
4059                        end_position = end_region.range.start;
4060                        debug_assert!(end_region.is_main_buffer);
4061                        let region_buffer_start = end_region.buffer_range.start;
4062                        if metadata_buffer_range.end > region_buffer_start {
4063                            end_position
4064                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4065                        }
4066                        end_position = end_position.min(end_region.range.end);
4067                    }
4068
4069                    if start_position <= query_range.end && end_position >= query_range.start {
4070                        return Some((start_position..end_position, metadata, excerpt));
4071                    }
4072                }
4073                // When there are no more metadata items for this excerpt, move to the next excerpt.
4074                else {
4075                    current_excerpt_metadata.take();
4076                    if let Some((end_excerpt_id, _)) = range_end {
4077                        if excerpt.id == end_excerpt_id {
4078                            return None;
4079                        }
4080                    }
4081                    cursor.next_excerpt();
4082                }
4083            }
4084        })
4085    }
4086
4087    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4088        let offset = position.to_offset(self);
4089
4090        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4091        cursor.seek(&DimensionPair {
4092            key: offset,
4093            value: None,
4094        });
4095        cursor.seek_to_start_of_current_excerpt();
4096        let excerpt = cursor.excerpt()?;
4097
4098        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4099        let current_position = self
4100            .anchor_before(offset)
4101            .text_anchor
4102            .to_offset(&excerpt.buffer);
4103        let excerpt_end = excerpt
4104            .buffer
4105            .anchor_before(excerpt_end.min(current_position));
4106
4107        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4108            for hunk in diff.hunks_intersecting_range_rev(
4109                excerpt.range.context.start..excerpt_end,
4110                &excerpt.buffer,
4111            ) {
4112                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4113                if hunk_end >= current_position {
4114                    continue;
4115                }
4116                let start =
4117                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4118                        .to_point(&self);
4119                return Some(MultiBufferRow(start.row));
4120            }
4121        }
4122
4123        loop {
4124            cursor.prev_excerpt();
4125            let excerpt = cursor.excerpt()?;
4126
4127            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4128                continue;
4129            };
4130            let mut hunks =
4131                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4132            let Some(hunk) = hunks.next() else {
4133                continue;
4134            };
4135            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4136                .to_point(&self);
4137            return Some(MultiBufferRow(start.row));
4138        }
4139    }
4140
4141    pub fn has_diff_hunks(&self) -> bool {
4142        self.diffs.values().any(|diff| !diff.is_empty())
4143    }
4144
4145    pub fn surrounding_word<T: ToOffset>(
4146        &self,
4147        start: T,
4148        for_completion: bool,
4149    ) -> (Range<usize>, Option<CharKind>) {
4150        let mut start = start.to_offset(self);
4151        let mut end = start;
4152        let mut next_chars = self.chars_at(start).peekable();
4153        let mut prev_chars = self.reversed_chars_at(start).peekable();
4154
4155        let classifier = self
4156            .char_classifier_at(start)
4157            .for_completion(for_completion);
4158
4159        let word_kind = cmp::max(
4160            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4161            next_chars.peek().copied().map(|c| classifier.kind(c)),
4162        );
4163
4164        for ch in prev_chars {
4165            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4166                start -= ch.len_utf8();
4167            } else {
4168                break;
4169            }
4170        }
4171
4172        for ch in next_chars {
4173            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4174                end += ch.len_utf8();
4175            } else {
4176                break;
4177            }
4178        }
4179
4180        (start..end, word_kind)
4181    }
4182
4183    pub fn is_singleton(&self) -> bool {
4184        self.singleton
4185    }
4186
4187    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4188        if self.singleton {
4189            self.excerpts
4190                .iter()
4191                .next()
4192                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4193        } else {
4194            None
4195        }
4196    }
4197
4198    pub fn len(&self) -> usize {
4199        self.diff_transforms.summary().output.len
4200    }
4201
4202    pub fn is_empty(&self) -> bool {
4203        self.excerpts.summary().text.len == 0
4204    }
4205
4206    pub fn widest_line_number(&self) -> u32 {
4207        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4208        self.excerpts.summary().widest_line_number + 1
4209    }
4210
4211    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
4212        let range = range.start.to_offset(self)..range.end.to_offset(self);
4213        let mut excerpts = self.cursor::<usize>();
4214        excerpts.seek(&range.start);
4215
4216        let mut chunk;
4217        let mut has_trailing_newline;
4218        let excerpt_bytes;
4219        if let Some(region) = excerpts.region() {
4220            let mut bytes = region.buffer.bytes_in_range(
4221                region.buffer_range.start + range.start - region.range.start
4222                    ..(region.buffer_range.start + range.end - region.range.start)
4223                        .min(region.buffer_range.end),
4224            );
4225            chunk = bytes.next().unwrap_or(&[][..]);
4226            excerpt_bytes = Some(bytes);
4227            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4228            if chunk.is_empty() && has_trailing_newline {
4229                chunk = b"\n";
4230                has_trailing_newline = false;
4231            }
4232        } else {
4233            chunk = &[][..];
4234            excerpt_bytes = None;
4235            has_trailing_newline = false;
4236        };
4237
4238        MultiBufferBytes {
4239            range,
4240            cursor: excerpts,
4241            excerpt_bytes,
4242            has_trailing_newline,
4243            chunk,
4244        }
4245    }
4246
4247    pub fn reversed_bytes_in_range<T: ToOffset>(
4248        &self,
4249        range: Range<T>,
4250    ) -> ReversedMultiBufferBytes {
4251        let range = range.start.to_offset(self)..range.end.to_offset(self);
4252        let mut chunks = self.reversed_chunks_in_range(range.clone());
4253        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4254        ReversedMultiBufferBytes {
4255            range,
4256            chunks,
4257            chunk,
4258        }
4259    }
4260
4261    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4262        let mut cursor = self.cursor::<Point>();
4263        cursor.seek(&Point::new(start_row.0, 0));
4264        let mut result = MultiBufferRows {
4265            point: Point::new(0, 0),
4266            is_empty: self.excerpts.is_empty(),
4267            is_singleton: self.is_singleton(),
4268            cursor,
4269        };
4270        result.seek(start_row);
4271        result
4272    }
4273
4274    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4275        let mut chunks = MultiBufferChunks {
4276            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4277            range: 0..0,
4278            excerpts: self.excerpts.cursor(&()),
4279            diff_transforms: self.diff_transforms.cursor(&()),
4280            diffs: &self.diffs,
4281            diff_base_chunks: None,
4282            excerpt_chunks: None,
4283            buffer_chunk: None,
4284            language_aware,
4285        };
4286        let range = range.start.to_offset(self)..range.end.to_offset(self);
4287        chunks.seek(range);
4288        chunks
4289    }
4290
4291    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4292        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4293    }
4294
4295    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4296        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4297    }
4298
4299    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4300        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4301    }
4302
4303    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4304        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4305            buffer.clip_point_utf16(Unclipped(point), bias)
4306        })
4307    }
4308
4309    pub fn offset_to_point(&self, offset: usize) -> Point {
4310        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4311    }
4312
4313    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4314        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4315    }
4316
4317    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4318        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4319    }
4320
4321    pub fn point_to_offset(&self, point: Point) -> usize {
4322        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4323    }
4324
4325    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4326        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4327    }
4328
4329    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4330        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4331    }
4332
4333    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4334        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4335    }
4336
4337    fn clip_dimension<D>(
4338        &self,
4339        position: D,
4340        bias: Bias,
4341        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4342    ) -> D
4343    where
4344        D: TextDimension + Ord + Sub<D, Output = D>,
4345    {
4346        let mut cursor = self.cursor();
4347        cursor.seek(&position);
4348        if let Some(region) = cursor.region() {
4349            if position >= region.range.end {
4350                return region.range.end;
4351            }
4352            let overshoot = position - region.range.start;
4353            let mut buffer_position = region.buffer_range.start;
4354            buffer_position.add_assign(&overshoot);
4355            let clipped_buffer_position =
4356                clip_buffer_position(&region.buffer, buffer_position, bias);
4357            let mut position = region.range.start;
4358            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4359            position
4360        } else {
4361            D::from_text_summary(&self.text_summary())
4362        }
4363    }
4364
4365    fn convert_dimension<D1, D2>(
4366        &self,
4367        key: D1,
4368        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4369    ) -> D2
4370    where
4371        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4372        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4373    {
4374        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4375        cursor.seek(&DimensionPair { key, value: None });
4376        if let Some(region) = cursor.region() {
4377            if key >= region.range.end.key {
4378                return region.range.end.value.unwrap();
4379            }
4380            let start_key = region.range.start.key;
4381            let start_value = region.range.start.value.unwrap();
4382            let buffer_start_key = region.buffer_range.start.key;
4383            let buffer_start_value = region.buffer_range.start.value.unwrap();
4384            let mut buffer_key = buffer_start_key;
4385            buffer_key.add_assign(&(key - start_key));
4386            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4387            let mut result = start_value;
4388            result.add_assign(&(buffer_value - buffer_start_value));
4389            result
4390        } else {
4391            D2::from_text_summary(&self.text_summary())
4392        }
4393    }
4394
4395    pub fn point_to_buffer_offset<T: ToOffset>(
4396        &self,
4397        point: T,
4398    ) -> Option<(&BufferSnapshot, usize)> {
4399        let offset = point.to_offset(self);
4400        let mut cursor = self.cursor::<usize>();
4401        cursor.seek(&offset);
4402        let region = cursor.region()?;
4403        let overshoot = offset - region.range.start;
4404        let buffer_offset = region.buffer_range.start + overshoot;
4405        if buffer_offset == region.buffer.len() + 1
4406            && region.has_trailing_newline
4407            && !region.is_main_buffer
4408        {
4409            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4410        } else if buffer_offset > region.buffer.len() {
4411            return None;
4412        }
4413        Some((region.buffer, buffer_offset))
4414    }
4415
4416    pub fn point_to_buffer_point(
4417        &self,
4418        point: Point,
4419    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4420        let mut cursor = self.cursor::<Point>();
4421        cursor.seek(&point);
4422        let region = cursor.region()?;
4423        let overshoot = point - region.range.start;
4424        let buffer_point = region.buffer_range.start + overshoot;
4425        let excerpt = cursor.excerpt()?;
4426        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4427            && region.has_trailing_newline
4428            && !region.is_main_buffer
4429        {
4430            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4431        } else if buffer_point > region.buffer.max_point() {
4432            return None;
4433        }
4434        Some((region.buffer, buffer_point, excerpt.id))
4435    }
4436
4437    pub fn suggested_indents(
4438        &self,
4439        rows: impl IntoIterator<Item = u32>,
4440        cx: &App,
4441    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4442        let mut result = BTreeMap::new();
4443
4444        let mut rows_for_excerpt = Vec::new();
4445        let mut cursor = self.cursor::<Point>();
4446        let mut rows = rows.into_iter().peekable();
4447        let mut prev_row = u32::MAX;
4448        let mut prev_language_indent_size = IndentSize::default();
4449
4450        while let Some(row) = rows.next() {
4451            cursor.seek(&Point::new(row, 0));
4452            let Some(region) = cursor.region() else {
4453                continue;
4454            };
4455
4456            // Retrieve the language and indent size once for each disjoint region being indented.
4457            let single_indent_size = if row.saturating_sub(1) == prev_row {
4458                prev_language_indent_size
4459            } else {
4460                region
4461                    .buffer
4462                    .language_indent_size_at(Point::new(row, 0), cx)
4463            };
4464            prev_language_indent_size = single_indent_size;
4465            prev_row = row;
4466
4467            let start_buffer_row = region.buffer_range.start.row;
4468            let start_multibuffer_row = region.range.start.row;
4469            let end_multibuffer_row = region.range.end.row;
4470
4471            rows_for_excerpt.push(row);
4472            while let Some(next_row) = rows.peek().copied() {
4473                if end_multibuffer_row > next_row {
4474                    rows_for_excerpt.push(next_row);
4475                    rows.next();
4476                } else {
4477                    break;
4478                }
4479            }
4480
4481            let buffer_rows = rows_for_excerpt
4482                .drain(..)
4483                .map(|row| start_buffer_row + row - start_multibuffer_row);
4484            let buffer_indents = region
4485                .buffer
4486                .suggested_indents(buffer_rows, single_indent_size);
4487            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4488                (
4489                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4490                    indent,
4491                )
4492            });
4493            result.extend(multibuffer_indents);
4494        }
4495
4496        result
4497    }
4498
4499    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4500        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4501            let mut size = buffer.indent_size_for_line(range.start.row);
4502            size.len = size
4503                .len
4504                .min(range.end.column)
4505                .saturating_sub(range.start.column);
4506            size
4507        } else {
4508            IndentSize::spaces(0)
4509        }
4510    }
4511
4512    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4513        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4514            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4515        } else {
4516            LineIndent::spaces(0)
4517        }
4518    }
4519
4520    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4521        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4522
4523        if self.language_settings(cx).extend_comment_on_newline {
4524            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4525                let delimiters = language_scope.line_comment_prefixes();
4526                for delimiter in delimiters {
4527                    if *self
4528                        .chars_at(Point::new(row.0, indent.len() as u32))
4529                        .take(delimiter.chars().count())
4530                        .collect::<String>()
4531                        .as_str()
4532                        == **delimiter
4533                    {
4534                        indent.push_str(&delimiter);
4535                        break;
4536                    }
4537                }
4538            }
4539        }
4540
4541        indent
4542    }
4543
4544    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4545    where
4546        T: ToOffset,
4547    {
4548        for char in self.reversed_chars_at(position) {
4549            if !char.is_whitespace() {
4550                return false;
4551            }
4552            if char == '\n' {
4553                return true;
4554            }
4555        }
4556        return true;
4557    }
4558
4559    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4560        while row.0 > 0 {
4561            row.0 -= 1;
4562            if !self.is_line_blank(row) {
4563                return Some(row);
4564            }
4565        }
4566        None
4567    }
4568
4569    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4570        if let Some((_, range)) = self.buffer_line_for_row(row) {
4571            range.end.column - range.start.column
4572        } else {
4573            0
4574        }
4575    }
4576
4577    pub fn buffer_line_for_row(
4578        &self,
4579        row: MultiBufferRow,
4580    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4581        let mut cursor = self.cursor::<Point>();
4582        let point = Point::new(row.0, 0);
4583        cursor.seek(&point);
4584        let region = cursor.region()?;
4585        let overshoot = point.min(region.range.end) - region.range.start;
4586        let buffer_point = region.buffer_range.start + overshoot;
4587        if buffer_point.row > region.buffer_range.end.row {
4588            return None;
4589        }
4590        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4591        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4592            .min(region.buffer_range.end);
4593        Some((region.buffer, line_start..line_end))
4594    }
4595
4596    pub fn max_point(&self) -> Point {
4597        self.text_summary().lines
4598    }
4599
4600    pub fn max_row(&self) -> MultiBufferRow {
4601        MultiBufferRow(self.text_summary().lines.row)
4602    }
4603
4604    pub fn text_summary(&self) -> TextSummary {
4605        self.diff_transforms.summary().output
4606    }
4607
4608    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4609    where
4610        D: TextDimension,
4611        O: ToOffset,
4612    {
4613        let range = range.start.to_offset(self)..range.end.to_offset(self);
4614        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4615        cursor.seek(&range.start, Bias::Right, &());
4616
4617        let Some(first_transform) = cursor.item() else {
4618            return D::from_text_summary(&TextSummary::default());
4619        };
4620
4621        let diff_transform_start = cursor.start().0;
4622        let diff_transform_end = cursor.end(&()).0;
4623        let diff_start = range.start;
4624        let start_overshoot = diff_start - diff_transform_start;
4625        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4626
4627        let mut result = match first_transform {
4628            DiffTransform::BufferContent { .. } => {
4629                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4630                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4631                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4632            }
4633            DiffTransform::DeletedHunk {
4634                buffer_id,
4635                base_text_byte_range,
4636                has_trailing_newline,
4637                ..
4638            } => {
4639                let buffer_start = base_text_byte_range.start + start_overshoot;
4640                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4641                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4642                    panic!("{:?} is in non-existent deleted hunk", range.start)
4643                };
4644
4645                let include_trailing_newline =
4646                    *has_trailing_newline && range.end >= diff_transform_end;
4647                if include_trailing_newline {
4648                    buffer_end -= 1;
4649                }
4650
4651                let mut summary =
4652                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4653
4654                if include_trailing_newline {
4655                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4656                }
4657
4658                summary
4659            }
4660        };
4661        if range.end < diff_transform_end {
4662            return result;
4663        }
4664
4665        cursor.next(&());
4666        result.add_assign(&D::from_text_summary(&cursor.summary(
4667            &range.end,
4668            Bias::Right,
4669            &(),
4670        )));
4671
4672        let Some(last_transform) = cursor.item() else {
4673            return result;
4674        };
4675
4676        let overshoot = range.end - cursor.start().0;
4677        let suffix = match last_transform {
4678            DiffTransform::BufferContent { .. } => {
4679                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4680                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4681            }
4682            DiffTransform::DeletedHunk {
4683                base_text_byte_range,
4684                buffer_id,
4685                has_trailing_newline,
4686                ..
4687            } => {
4688                let buffer_end = base_text_byte_range.start + overshoot;
4689                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4690                    panic!("{:?} is in non-existent deleted hunk", range.end)
4691                };
4692
4693                let mut suffix = base_text
4694                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4695                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4696                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4697                }
4698                suffix
4699            }
4700        };
4701
4702        result.add_assign(&suffix);
4703        result
4704    }
4705
4706    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4707    where
4708        D: TextDimension,
4709    {
4710        // let mut range = range.start..range.end;
4711        let mut summary = D::zero(&());
4712        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4713        cursor.seek(&range.start, Bias::Right, &());
4714        if let Some(excerpt) = cursor.item() {
4715            let mut end_before_newline = cursor.end(&());
4716            if excerpt.has_trailing_newline {
4717                end_before_newline -= ExcerptOffset::new(1);
4718            }
4719
4720            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4721            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4722            let end_in_excerpt =
4723                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4724            summary.add_assign(
4725                &excerpt
4726                    .buffer
4727                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4728            );
4729
4730            if range.end > end_before_newline {
4731                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4732            }
4733
4734            cursor.next(&());
4735        }
4736
4737        if range.end > *cursor.start() {
4738            summary.add_assign(
4739                &cursor
4740                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4741                    .0,
4742            );
4743            if let Some(excerpt) = cursor.item() {
4744                range.end = cmp::max(*cursor.start(), range.end);
4745
4746                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4747                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4748                summary.add_assign(
4749                    &excerpt
4750                        .buffer
4751                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4752                );
4753            }
4754        }
4755
4756        summary
4757    }
4758
4759    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4760    where
4761        D: TextDimension + Ord + Sub<D, Output = D>,
4762    {
4763        self.summaries_for_anchors([anchor])[0]
4764    }
4765
4766    fn resolve_summary_for_anchor<D>(
4767        &self,
4768        anchor: &Anchor,
4769        excerpt_position: D,
4770        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4771    ) -> D
4772    where
4773        D: TextDimension + Ord + Sub<D, Output = D>,
4774    {
4775        loop {
4776            let transform_end_position = diff_transforms.end(&()).0.0;
4777            let at_transform_end =
4778                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4779            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4780                diff_transforms.next(&());
4781                continue;
4782            }
4783
4784            let mut position = diff_transforms.start().1.0;
4785            match diff_transforms.item() {
4786                Some(DiffTransform::DeletedHunk {
4787                    buffer_id,
4788                    base_text_byte_range,
4789                    ..
4790                }) => {
4791                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4792                        if let Some(base_text) =
4793                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4794                        {
4795                            if base_text.can_resolve(&diff_base_anchor) {
4796                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4797                                if base_text_offset >= base_text_byte_range.start
4798                                    && base_text_offset <= base_text_byte_range.end
4799                                {
4800                                    let position_in_hunk = base_text
4801                                        .text_summary_for_range::<D, _>(
4802                                            base_text_byte_range.start..base_text_offset,
4803                                        );
4804                                    position.add_assign(&position_in_hunk);
4805                                } else if at_transform_end {
4806                                    diff_transforms.next(&());
4807                                    continue;
4808                                }
4809                            }
4810                        }
4811                    }
4812                }
4813                _ => {
4814                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4815                        diff_transforms.next(&());
4816                        continue;
4817                    }
4818                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4819                    position.add_assign(&overshoot);
4820                }
4821            }
4822
4823            return position;
4824        }
4825    }
4826
4827    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4828        let mut cursor = self
4829            .excerpts
4830            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4831        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4832
4833        cursor.seek(&Some(locator), Bias::Left, &());
4834        if cursor.item().is_none() {
4835            cursor.next(&());
4836        }
4837
4838        let mut position = cursor.start().1;
4839        if let Some(excerpt) = cursor.item() {
4840            if excerpt.id == anchor.excerpt_id {
4841                let excerpt_buffer_start = excerpt
4842                    .buffer
4843                    .offset_for_anchor(&excerpt.range.context.start);
4844                let excerpt_buffer_end =
4845                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4846                let buffer_position = cmp::min(
4847                    excerpt_buffer_end,
4848                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4849                );
4850                if buffer_position > excerpt_buffer_start {
4851                    position.value += buffer_position - excerpt_buffer_start;
4852                }
4853            }
4854        }
4855        position
4856    }
4857
4858    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4859        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4860            excerpt_id = *replacement;
4861        }
4862        return excerpt_id;
4863    }
4864
4865    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4866    where
4867        D: TextDimension + Ord + Sub<D, Output = D>,
4868        I: 'a + IntoIterator<Item = &'a Anchor>,
4869    {
4870        let mut anchors = anchors.into_iter().peekable();
4871        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4872        let mut diff_transforms_cursor = self
4873            .diff_transforms
4874            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4875        diff_transforms_cursor.next(&());
4876
4877        let mut summaries = Vec::new();
4878        while let Some(anchor) = anchors.peek() {
4879            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4880            let excerpt_anchors = iter::from_fn(|| {
4881                let anchor = anchors.peek()?;
4882                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4883                    Some(anchors.next().unwrap())
4884                } else {
4885                    None
4886                }
4887            });
4888
4889            let locator = self.excerpt_locator_for_id(excerpt_id);
4890            cursor.seek_forward(locator, Bias::Left, &());
4891            if cursor.item().is_none() {
4892                cursor.next(&());
4893            }
4894
4895            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4896            if let Some(excerpt) = cursor.item() {
4897                if excerpt.id != excerpt_id {
4898                    let position = self.resolve_summary_for_anchor(
4899                        &Anchor::min(),
4900                        excerpt_start_position,
4901                        &mut diff_transforms_cursor,
4902                    );
4903                    summaries.extend(excerpt_anchors.map(|_| position));
4904                    continue;
4905                }
4906                let excerpt_buffer_start =
4907                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4908                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4909                for (buffer_summary, anchor) in excerpt
4910                    .buffer
4911                    .summaries_for_anchors_with_payload::<D, _, _>(
4912                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4913                    )
4914                {
4915                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4916                    let mut position = excerpt_start_position;
4917                    if summary > excerpt_buffer_start {
4918                        position.add_assign(&(summary - excerpt_buffer_start));
4919                    }
4920
4921                    if position > diff_transforms_cursor.start().0.0 {
4922                        diff_transforms_cursor.seek_forward(
4923                            &ExcerptDimension(position),
4924                            Bias::Left,
4925                            &(),
4926                        );
4927                    }
4928
4929                    summaries.push(self.resolve_summary_for_anchor(
4930                        anchor,
4931                        position,
4932                        &mut diff_transforms_cursor,
4933                    ));
4934                }
4935            } else {
4936                diff_transforms_cursor.seek_forward(
4937                    &ExcerptDimension(excerpt_start_position),
4938                    Bias::Left,
4939                    &(),
4940                );
4941                let position = self.resolve_summary_for_anchor(
4942                    &Anchor::max(),
4943                    excerpt_start_position,
4944                    &mut diff_transforms_cursor,
4945                );
4946                summaries.extend(excerpt_anchors.map(|_| position));
4947            }
4948        }
4949
4950        summaries
4951    }
4952
4953    pub fn dimensions_from_points<'a, D>(
4954        &'a self,
4955        points: impl 'a + IntoIterator<Item = Point>,
4956    ) -> impl 'a + Iterator<Item = D>
4957    where
4958        D: TextDimension + Sub<D, Output = D>,
4959    {
4960        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4961        cursor.seek(&DimensionPair {
4962            key: Point::default(),
4963            value: None,
4964        });
4965        let mut points = points.into_iter();
4966        iter::from_fn(move || {
4967            let point = points.next()?;
4968
4969            cursor.seek_forward(&DimensionPair {
4970                key: point,
4971                value: None,
4972            });
4973
4974            if let Some(region) = cursor.region() {
4975                let overshoot = point - region.range.start.key;
4976                let buffer_point = region.buffer_range.start.key + overshoot;
4977                let mut position = region.range.start.value.unwrap();
4978                position.add_assign(
4979                    &region
4980                        .buffer
4981                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4982                );
4983                if point == region.range.end.key && region.has_trailing_newline {
4984                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4985                }
4986                return Some(position);
4987            } else {
4988                return Some(D::from_text_summary(&self.text_summary()));
4989            }
4990        })
4991    }
4992
4993    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4994    where
4995        I: 'a + IntoIterator<Item = &'a Anchor>,
4996    {
4997        let mut anchors = anchors.into_iter().enumerate().peekable();
4998        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4999        cursor.next(&());
5000
5001        let mut result = Vec::new();
5002
5003        while let Some((_, anchor)) = anchors.peek() {
5004            let old_excerpt_id = anchor.excerpt_id;
5005
5006            // Find the location where this anchor's excerpt should be.
5007            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5008            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
5009
5010            if cursor.item().is_none() {
5011                cursor.next(&());
5012            }
5013
5014            let next_excerpt = cursor.item();
5015            let prev_excerpt = cursor.prev_item();
5016
5017            // Process all of the anchors for this excerpt.
5018            while let Some((_, anchor)) = anchors.peek() {
5019                if anchor.excerpt_id != old_excerpt_id {
5020                    break;
5021                }
5022                let (anchor_ix, anchor) = anchors.next().unwrap();
5023                let mut anchor = *anchor;
5024
5025                // Leave min and max anchors unchanged if invalid or
5026                // if the old excerpt still exists at this location
5027                let mut kept_position = next_excerpt
5028                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
5029                    || old_excerpt_id == ExcerptId::max()
5030                    || old_excerpt_id == ExcerptId::min();
5031
5032                // If the old excerpt no longer exists at this location, then attempt to
5033                // find an equivalent position for this anchor in an adjacent excerpt.
5034                if !kept_position {
5035                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5036                        if excerpt.contains(&anchor) {
5037                            anchor.excerpt_id = excerpt.id;
5038                            kept_position = true;
5039                            break;
5040                        }
5041                    }
5042                }
5043
5044                // If there's no adjacent excerpt that contains the anchor's position,
5045                // then report that the anchor has lost its position.
5046                if !kept_position {
5047                    anchor = if let Some(excerpt) = next_excerpt {
5048                        let mut text_anchor = excerpt
5049                            .range
5050                            .context
5051                            .start
5052                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5053                        if text_anchor
5054                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5055                            .is_gt()
5056                        {
5057                            text_anchor = excerpt.range.context.end;
5058                        }
5059                        Anchor {
5060                            buffer_id: Some(excerpt.buffer_id),
5061                            excerpt_id: excerpt.id,
5062                            text_anchor,
5063                            diff_base_anchor: None,
5064                        }
5065                    } else if let Some(excerpt) = prev_excerpt {
5066                        let mut text_anchor = excerpt
5067                            .range
5068                            .context
5069                            .end
5070                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5071                        if text_anchor
5072                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5073                            .is_lt()
5074                        {
5075                            text_anchor = excerpt.range.context.start;
5076                        }
5077                        Anchor {
5078                            buffer_id: Some(excerpt.buffer_id),
5079                            excerpt_id: excerpt.id,
5080                            text_anchor,
5081                            diff_base_anchor: None,
5082                        }
5083                    } else if anchor.text_anchor.bias == Bias::Left {
5084                        Anchor::min()
5085                    } else {
5086                        Anchor::max()
5087                    };
5088                }
5089
5090                result.push((anchor_ix, anchor, kept_position));
5091            }
5092        }
5093        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5094        result
5095    }
5096
5097    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5098        self.anchor_at(position, Bias::Left)
5099    }
5100
5101    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5102        self.anchor_at(position, Bias::Right)
5103    }
5104
5105    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5106        let offset = position.to_offset(self);
5107
5108        // Find the given position in the diff transforms. Determine the corresponding
5109        // offset in the excerpts, and whether the position is within a deleted hunk.
5110        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
5111        diff_transforms.seek(&offset, Bias::Right, &());
5112
5113        if offset == diff_transforms.start().0 && bias == Bias::Left {
5114            if let Some(prev_item) = diff_transforms.prev_item() {
5115                match prev_item {
5116                    DiffTransform::DeletedHunk { .. } => {
5117                        diff_transforms.prev(&());
5118                    }
5119                    _ => {}
5120                }
5121            }
5122        }
5123        let offset_in_transform = offset - diff_transforms.start().0;
5124        let mut excerpt_offset = diff_transforms.start().1;
5125        let mut diff_base_anchor = None;
5126        if let Some(DiffTransform::DeletedHunk {
5127            buffer_id,
5128            base_text_byte_range,
5129            has_trailing_newline,
5130            ..
5131        }) = diff_transforms.item()
5132        {
5133            let diff = self.diffs.get(buffer_id).expect("missing diff");
5134            if offset_in_transform > base_text_byte_range.len() {
5135                debug_assert!(*has_trailing_newline);
5136                bias = Bias::Right;
5137            } else {
5138                diff_base_anchor = Some(
5139                    diff.base_text()
5140                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5141                );
5142                bias = Bias::Left;
5143            }
5144        } else {
5145            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5146        };
5147
5148        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5149            return Anchor {
5150                buffer_id: Some(buffer_id),
5151                excerpt_id: *excerpt_id,
5152                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5153                diff_base_anchor,
5154            };
5155        }
5156
5157        let mut excerpts = self
5158            .excerpts
5159            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5160        excerpts.seek(&excerpt_offset, Bias::Right, &());
5161        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5162            excerpts.prev(&());
5163        }
5164        if let Some(excerpt) = excerpts.item() {
5165            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5166            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5167                overshoot -= 1;
5168                bias = Bias::Right;
5169            }
5170
5171            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5172            let text_anchor =
5173                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5174            Anchor {
5175                buffer_id: Some(excerpt.buffer_id),
5176                excerpt_id: excerpt.id,
5177                text_anchor,
5178                diff_base_anchor,
5179            }
5180        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5181            Anchor::min()
5182        } else {
5183            Anchor::max()
5184        }
5185    }
5186
5187    /// Returns an anchor for the given excerpt and text anchor,
5188    /// returns None if the excerpt_id is no longer valid.
5189    pub fn anchor_in_excerpt(
5190        &self,
5191        excerpt_id: ExcerptId,
5192        text_anchor: text::Anchor,
5193    ) -> Option<Anchor> {
5194        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5195        let locator = self.excerpt_locator_for_id(excerpt_id);
5196        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5197        cursor.seek(locator, Bias::Left, &());
5198        if let Some(excerpt) = cursor.item() {
5199            if excerpt.id == excerpt_id {
5200                let text_anchor = excerpt.clip_anchor(text_anchor);
5201                drop(cursor);
5202                return Some(Anchor {
5203                    buffer_id: Some(excerpt.buffer_id),
5204                    excerpt_id,
5205                    text_anchor,
5206                    diff_base_anchor: None,
5207                });
5208            }
5209        }
5210        None
5211    }
5212
5213    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5214        Some(self.excerpt(excerpt_id)?.range.context.clone())
5215    }
5216
5217    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5218        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5219            true
5220        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5221            excerpt.buffer.can_resolve(&anchor.text_anchor)
5222        } else {
5223            false
5224        }
5225    }
5226
5227    pub fn excerpts(
5228        &self,
5229    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5230        self.excerpts
5231            .iter()
5232            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5233    }
5234
5235    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
5236        let excerpts = self.excerpts.cursor(&());
5237        let diff_transforms = self.diff_transforms.cursor(&());
5238        MultiBufferCursor {
5239            excerpts,
5240            diff_transforms,
5241            diffs: &self.diffs,
5242            cached_region: None,
5243        }
5244    }
5245
5246    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5247        let start_locator = self.excerpt_locator_for_id(id);
5248        let mut excerpts = self
5249            .excerpts
5250            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5251        excerpts.seek(&Some(start_locator), Bias::Left, &());
5252        excerpts.prev(&());
5253
5254        let mut diff_transforms = self
5255            .diff_transforms
5256            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5257        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5258        if diff_transforms.end(&()).1 < excerpts.start().1 {
5259            diff_transforms.next(&());
5260        }
5261
5262        let excerpt = excerpts.item()?;
5263        Some(MultiBufferExcerpt {
5264            excerpt,
5265            offset: diff_transforms.start().0.0,
5266            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5267            excerpt_offset: excerpts.start().1.clone(),
5268            diff_transforms,
5269        })
5270    }
5271
5272    pub fn excerpt_boundaries_in_range<R, T>(
5273        &self,
5274        range: R,
5275    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5276    where
5277        R: RangeBounds<T>,
5278        T: ToOffset,
5279    {
5280        let start_offset;
5281        let start = match range.start_bound() {
5282            Bound::Included(start) => {
5283                start_offset = start.to_offset(self);
5284                Bound::Included(start_offset)
5285            }
5286            Bound::Excluded(_) => {
5287                panic!("not supported")
5288            }
5289            Bound::Unbounded => {
5290                start_offset = 0;
5291                Bound::Unbounded
5292            }
5293        };
5294        let end = match range.end_bound() {
5295            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5296            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5297            Bound::Unbounded => Bound::Unbounded,
5298        };
5299        let bounds = (start, end);
5300
5301        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5302        cursor.seek(&DimensionPair {
5303            key: start_offset,
5304            value: None,
5305        });
5306
5307        if cursor
5308            .region()
5309            .is_some_and(|region| bounds.contains(&region.range.start.key))
5310        {
5311            cursor.prev_excerpt();
5312        } else {
5313            cursor.seek_to_start_of_current_excerpt();
5314        }
5315        let mut prev_region = cursor.region();
5316
5317        cursor.next_excerpt();
5318
5319        iter::from_fn(move || {
5320            loop {
5321                if self.singleton {
5322                    return None;
5323                }
5324
5325                let next_region = cursor.region()?;
5326                cursor.next_excerpt();
5327                if !bounds.contains(&next_region.range.start.key) {
5328                    prev_region = Some(next_region);
5329                    continue;
5330                }
5331
5332                let next_region_start = next_region.range.start.value.unwrap();
5333                let next_region_end = if let Some(region) = cursor.region() {
5334                    region.range.start.value.unwrap()
5335                } else {
5336                    self.max_point()
5337                };
5338
5339                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5340                    id: region.excerpt.id,
5341                    buffer: region.excerpt.buffer.clone(),
5342                    buffer_id: region.excerpt.buffer_id,
5343                    range: region.excerpt.range.clone(),
5344                    end_row: MultiBufferRow(next_region_start.row),
5345                });
5346
5347                let next = ExcerptInfo {
5348                    id: next_region.excerpt.id,
5349                    buffer: next_region.excerpt.buffer.clone(),
5350                    buffer_id: next_region.excerpt.buffer_id,
5351                    range: next_region.excerpt.range.clone(),
5352                    end_row: if next_region.excerpt.has_trailing_newline {
5353                        MultiBufferRow(next_region_end.row - 1)
5354                    } else {
5355                        MultiBufferRow(next_region_end.row)
5356                    },
5357                };
5358
5359                let row = MultiBufferRow(next_region_start.row);
5360
5361                prev_region = Some(next_region);
5362
5363                return Some(ExcerptBoundary { row, prev, next });
5364            }
5365        })
5366    }
5367
5368    pub fn edit_count(&self) -> usize {
5369        self.edit_count
5370    }
5371
5372    pub fn non_text_state_update_count(&self) -> usize {
5373        self.non_text_state_update_count
5374    }
5375
5376    /// Returns the smallest enclosing bracket ranges containing the given range or
5377    /// None if no brackets contain range or the range is not contained in a single
5378    /// excerpt
5379    ///
5380    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5381    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5382        &self,
5383        range: Range<T>,
5384        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5385    ) -> Option<(Range<usize>, Range<usize>)> {
5386        let range = range.start.to_offset(self)..range.end.to_offset(self);
5387        let mut excerpt = self.excerpt_containing(range.clone())?;
5388        let buffer = excerpt.buffer();
5389        let excerpt_buffer_range = excerpt.buffer_range();
5390
5391        // Filter to ranges contained in the excerpt
5392        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5393            excerpt_buffer_range.contains(&open.start)
5394                && excerpt_buffer_range.contains(&close.end)
5395                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5396        };
5397
5398        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5399            excerpt.map_range_to_buffer(range),
5400            Some(&range_filter),
5401        )?;
5402
5403        Some((
5404            excerpt.map_range_from_buffer(open),
5405            excerpt.map_range_from_buffer(close),
5406        ))
5407    }
5408
5409    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5410    /// not contained in a single excerpt
5411    pub fn enclosing_bracket_ranges<T: ToOffset>(
5412        &self,
5413        range: Range<T>,
5414    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5415        let range = range.start.to_offset(self)..range.end.to_offset(self);
5416        let mut excerpt = self.excerpt_containing(range.clone())?;
5417
5418        Some(
5419            excerpt
5420                .buffer()
5421                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5422                .filter_map(move |pair| {
5423                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5424                        Some((
5425                            excerpt.map_range_from_buffer(pair.open_range),
5426                            excerpt.map_range_from_buffer(pair.close_range),
5427                        ))
5428                    } else {
5429                        None
5430                    }
5431                }),
5432        )
5433    }
5434
5435    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5436    /// not contained in a single excerpt
5437    pub fn text_object_ranges<T: ToOffset>(
5438        &self,
5439        range: Range<T>,
5440        options: TreeSitterOptions,
5441    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5442        let range = range.start.to_offset(self)..range.end.to_offset(self);
5443        self.excerpt_containing(range.clone())
5444            .map(|mut excerpt| {
5445                excerpt
5446                    .buffer()
5447                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5448                    .filter_map(move |(range, text_object)| {
5449                        if excerpt.contains_buffer_range(range.clone()) {
5450                            Some((excerpt.map_range_from_buffer(range), text_object))
5451                        } else {
5452                            None
5453                        }
5454                    })
5455            })
5456            .into_iter()
5457            .flatten()
5458    }
5459
5460    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5461    /// not contained in a single excerpt
5462    pub fn bracket_ranges<T: ToOffset>(
5463        &self,
5464        range: Range<T>,
5465    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5466        let range = range.start.to_offset(self)..range.end.to_offset(self);
5467        let mut excerpt = self.excerpt_containing(range.clone())?;
5468
5469        Some(
5470            excerpt
5471                .buffer()
5472                .bracket_ranges(excerpt.map_range_to_buffer(range))
5473                .filter_map(move |pair| {
5474                    let buffer_range = pair.open_range.start..pair.close_range.end;
5475                    if excerpt.contains_buffer_range(buffer_range) {
5476                        Some((
5477                            excerpt.map_range_from_buffer(pair.open_range),
5478                            excerpt.map_range_from_buffer(pair.close_range),
5479                        ))
5480                    } else {
5481                        None
5482                    }
5483                }),
5484        )
5485    }
5486
5487    pub fn redacted_ranges<'a, T: ToOffset>(
5488        &'a self,
5489        range: Range<T>,
5490        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5491    ) -> impl Iterator<Item = Range<usize>> + 'a {
5492        let range = range.start.to_offset(self)..range.end.to_offset(self);
5493        self.lift_buffer_metadata(range, move |buffer, range| {
5494            if redaction_enabled(buffer.file()) {
5495                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5496            } else {
5497                None
5498            }
5499        })
5500        .map(|(range, _, _)| range)
5501    }
5502
5503    pub fn runnable_ranges(
5504        &self,
5505        range: Range<Anchor>,
5506    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5507        let range = range.start.to_offset(self)..range.end.to_offset(self);
5508        self.lift_buffer_metadata(range, move |buffer, range| {
5509            Some(
5510                buffer
5511                    .runnable_ranges(range.clone())
5512                    .filter(move |runnable| {
5513                        runnable.run_range.start >= range.start
5514                            && runnable.run_range.end < range.end
5515                    })
5516                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5517            )
5518        })
5519        .map(|(run_range, runnable, _)| language::RunnableRange {
5520            run_range,
5521            ..runnable
5522        })
5523    }
5524
5525    pub fn line_indents(
5526        &self,
5527        start_row: MultiBufferRow,
5528        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5529    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5530        let max_point = self.max_point();
5531        let mut cursor = self.cursor::<Point>();
5532        cursor.seek(&Point::new(start_row.0, 0));
5533        iter::from_fn(move || {
5534            let mut region = cursor.region()?;
5535            while !buffer_filter(&region.excerpt.buffer) {
5536                cursor.next();
5537                region = cursor.region()?;
5538            }
5539            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5540            let buffer_start_row =
5541                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5542
5543            let buffer_end_row = if region.is_main_buffer
5544                && (region.has_trailing_newline || region.range.end == max_point)
5545            {
5546                region.buffer_range.end.row
5547            } else {
5548                region.buffer_range.end.row.saturating_sub(1)
5549            };
5550
5551            let line_indents = region
5552                .buffer
5553                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5554            cursor.next();
5555            return Some(line_indents.map(move |(buffer_row, indent)| {
5556                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5557                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5558            }));
5559        })
5560        .flatten()
5561    }
5562
5563    pub fn reversed_line_indents(
5564        &self,
5565        end_row: MultiBufferRow,
5566        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5567    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5568        let max_point = self.max_point();
5569        let mut cursor = self.cursor::<Point>();
5570        cursor.seek(&Point::new(end_row.0, 0));
5571        iter::from_fn(move || {
5572            let mut region = cursor.region()?;
5573            while !buffer_filter(&region.excerpt.buffer) {
5574                cursor.prev();
5575                region = cursor.region()?;
5576            }
5577
5578            let buffer_start_row = region.buffer_range.start.row;
5579            let buffer_end_row = if region.is_main_buffer
5580                && (region.has_trailing_newline || region.range.end == max_point)
5581            {
5582                region.buffer_range.end.row + 1
5583            } else {
5584                region.buffer_range.end.row
5585            };
5586
5587            let overshoot = end_row.0 - region.range.start.row;
5588            let buffer_end_row =
5589                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5590
5591            let line_indents = region
5592                .buffer
5593                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5594            cursor.prev();
5595            return Some(line_indents.map(move |(buffer_row, indent)| {
5596                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5597                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5598            }));
5599        })
5600        .flatten()
5601    }
5602
5603    pub async fn enclosing_indent(
5604        &self,
5605        mut target_row: MultiBufferRow,
5606    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5607        let max_row = MultiBufferRow(self.max_point().row);
5608        if target_row >= max_row {
5609            return None;
5610        }
5611
5612        let mut target_indent = self.line_indent_for_row(target_row);
5613
5614        // If the current row is at the start of an indented block, we want to return this
5615        // block as the enclosing indent.
5616        if !target_indent.is_line_empty() && target_row < max_row {
5617            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5618            if !next_line_indent.is_line_empty()
5619                && target_indent.raw_len() < next_line_indent.raw_len()
5620            {
5621                target_indent = next_line_indent;
5622                target_row.0 += 1;
5623            }
5624        }
5625
5626        const SEARCH_ROW_LIMIT: u32 = 25000;
5627        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5628        const YIELD_INTERVAL: u32 = 100;
5629
5630        let mut accessed_row_counter = 0;
5631
5632        // If there is a blank line at the current row, search for the next non indented lines
5633        if target_indent.is_line_empty() {
5634            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5635            let end =
5636                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5637
5638            let mut non_empty_line_above = None;
5639            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5640                if row < start {
5641                    break;
5642                }
5643                accessed_row_counter += 1;
5644                if accessed_row_counter == YIELD_INTERVAL {
5645                    accessed_row_counter = 0;
5646                    yield_now().await;
5647                }
5648                if !indent.is_line_empty() {
5649                    non_empty_line_above = Some((row, indent));
5650                    break;
5651                }
5652            }
5653
5654            let mut non_empty_line_below = None;
5655            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5656                if row > end {
5657                    break;
5658                }
5659                accessed_row_counter += 1;
5660                if accessed_row_counter == YIELD_INTERVAL {
5661                    accessed_row_counter = 0;
5662                    yield_now().await;
5663                }
5664                if !indent.is_line_empty() {
5665                    non_empty_line_below = Some((row, indent));
5666                    break;
5667                }
5668            }
5669
5670            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5671                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5672                    if above_indent.raw_len() >= below_indent.raw_len() {
5673                        (above_row, above_indent)
5674                    } else {
5675                        (below_row, below_indent)
5676                    }
5677                }
5678                (Some(above), None) => above,
5679                (None, Some(below)) => below,
5680                _ => return None,
5681            };
5682
5683            target_indent = indent;
5684            target_row = row;
5685        }
5686
5687        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5688        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5689
5690        let mut start_indent = None;
5691        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5692            if row < start {
5693                break;
5694            }
5695            accessed_row_counter += 1;
5696            if accessed_row_counter == YIELD_INTERVAL {
5697                accessed_row_counter = 0;
5698                yield_now().await;
5699            }
5700            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5701                start_indent = Some((row, indent));
5702                break;
5703            }
5704        }
5705        let (start_row, start_indent_size) = start_indent?;
5706
5707        let mut end_indent = (end, None);
5708        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5709            if row > end {
5710                break;
5711            }
5712            accessed_row_counter += 1;
5713            if accessed_row_counter == YIELD_INTERVAL {
5714                accessed_row_counter = 0;
5715                yield_now().await;
5716            }
5717            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5718                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5719                break;
5720            }
5721        }
5722        let (end_row, end_indent_size) = end_indent;
5723
5724        let indent = if let Some(end_indent_size) = end_indent_size {
5725            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5726                start_indent_size
5727            } else {
5728                end_indent_size
5729            }
5730        } else {
5731            start_indent_size
5732        };
5733
5734        Some((start_row..end_row, indent))
5735    }
5736
5737    pub fn indent_guides_in_range<T: ToPoint>(
5738        &self,
5739        range: Range<T>,
5740        ignore_disabled_for_language: bool,
5741        cx: &App,
5742    ) -> impl Iterator<Item = IndentGuide> {
5743        let range = range.start.to_point(self)..range.end.to_point(self);
5744        let start_row = MultiBufferRow(range.start.row);
5745        let end_row = MultiBufferRow(range.end.row);
5746
5747        let mut row_indents = self.line_indents(start_row, |buffer| {
5748            let settings =
5749                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5750            settings.indent_guides.enabled || ignore_disabled_for_language
5751        });
5752
5753        let mut result = Vec::new();
5754        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5755
5756        let mut prev_settings = None;
5757        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5758            if first_row > end_row {
5759                break;
5760            }
5761            let current_depth = indent_stack.len() as u32;
5762
5763            // Avoid retrieving the language settings repeatedly for every buffer row.
5764            if let Some((prev_buffer_id, _)) = &prev_settings {
5765                if prev_buffer_id != &buffer.remote_id() {
5766                    prev_settings.take();
5767                }
5768            }
5769            let settings = &prev_settings
5770                .get_or_insert_with(|| {
5771                    (
5772                        buffer.remote_id(),
5773                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5774                    )
5775                })
5776                .1;
5777            let tab_size = settings.tab_size.get();
5778
5779            // When encountering empty, continue until found useful line indent
5780            // then add to the indent stack with the depth found
5781            let mut found_indent = false;
5782            let mut last_row = first_row;
5783            if line_indent.is_line_blank() {
5784                while !found_indent {
5785                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5786                        break;
5787                    };
5788                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5789                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5790                        break;
5791                    }
5792
5793                    if new_line_indent.is_line_blank() {
5794                        continue;
5795                    }
5796                    last_row = target_row.min(end_row);
5797                    line_indent = new_line_indent;
5798                    found_indent = true;
5799                    break;
5800                }
5801            } else {
5802                found_indent = true
5803            }
5804
5805            let depth = if found_indent {
5806                line_indent.len(tab_size) / tab_size
5807                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5808            } else {
5809                0
5810            };
5811
5812            match depth.cmp(&current_depth) {
5813                cmp::Ordering::Less => {
5814                    for _ in 0..(current_depth - depth) {
5815                        let mut indent = indent_stack.pop().unwrap();
5816                        if last_row != first_row {
5817                            // In this case, we landed on an empty row, had to seek forward,
5818                            // and discovered that the indent we where on is ending.
5819                            // This means that the last display row must
5820                            // be on line that ends this indent range, so we
5821                            // should display the range up to the first non-empty line
5822                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5823                        }
5824
5825                        result.push(indent)
5826                    }
5827                }
5828                cmp::Ordering::Greater => {
5829                    for next_depth in current_depth..depth {
5830                        indent_stack.push(IndentGuide {
5831                            buffer_id: buffer.remote_id(),
5832                            start_row: first_row,
5833                            end_row: last_row,
5834                            depth: next_depth,
5835                            tab_size,
5836                            settings: settings.indent_guides,
5837                        });
5838                    }
5839                }
5840                _ => {}
5841            }
5842
5843            for indent in indent_stack.iter_mut() {
5844                indent.end_row = last_row;
5845            }
5846        }
5847
5848        result.extend(indent_stack);
5849        result.into_iter()
5850    }
5851
5852    pub fn trailing_excerpt_update_count(&self) -> usize {
5853        self.trailing_excerpt_update_count
5854    }
5855
5856    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5857        self.point_to_buffer_offset(point)
5858            .and_then(|(buffer, _)| buffer.file())
5859    }
5860
5861    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5862        self.point_to_buffer_offset(point)
5863            .and_then(|(buffer, offset)| buffer.language_at(offset))
5864    }
5865
5866    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5867        self.excerpts
5868            .first()
5869            .map(|excerpt| &excerpt.buffer)
5870            .map(|buffer| {
5871                language_settings(
5872                    buffer.language().map(|language| language.name()),
5873                    buffer.file(),
5874                    cx,
5875                )
5876            })
5877            .unwrap_or_else(move || self.language_settings_at(0, cx))
5878    }
5879
5880    pub fn language_settings_at<'a, T: ToOffset>(
5881        &'a self,
5882        point: T,
5883        cx: &'a App,
5884    ) -> Cow<'a, LanguageSettings> {
5885        let mut language = None;
5886        let mut file = None;
5887        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5888            language = buffer.language_at(offset);
5889            file = buffer.file();
5890        }
5891        language_settings(language.map(|l| l.name()), file, cx)
5892    }
5893
5894    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5895        self.point_to_buffer_offset(point)
5896            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5897    }
5898
5899    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5900        self.point_to_buffer_offset(point)
5901            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5902            .unwrap_or_default()
5903    }
5904
5905    pub fn language_indent_size_at<T: ToOffset>(
5906        &self,
5907        position: T,
5908        cx: &App,
5909    ) -> Option<IndentSize> {
5910        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5911        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5912    }
5913
5914    pub fn is_dirty(&self) -> bool {
5915        self.is_dirty
5916    }
5917
5918    pub fn has_deleted_file(&self) -> bool {
5919        self.has_deleted_file
5920    }
5921
5922    pub fn has_conflict(&self) -> bool {
5923        self.has_conflict
5924    }
5925
5926    pub fn has_diagnostics(&self) -> bool {
5927        self.excerpts
5928            .iter()
5929            .any(|excerpt| excerpt.buffer.has_diagnostics())
5930    }
5931
5932    pub fn diagnostic_group(
5933        &self,
5934        buffer_id: BufferId,
5935        group_id: usize,
5936    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5937        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
5938            if buffer.remote_id() != buffer_id {
5939                return None;
5940            };
5941            Some(
5942                buffer
5943                    .diagnostics_in_range(range, false)
5944                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5945                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5946            )
5947        })
5948        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5949    }
5950
5951    pub fn diagnostics_in_range<'a, T>(
5952        &'a self,
5953        range: Range<T>,
5954    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5955    where
5956        T: 'a
5957            + text::ToOffset
5958            + text::FromAnchor
5959            + TextDimension
5960            + Ord
5961            + Sub<T, Output = T>
5962            + fmt::Debug,
5963    {
5964        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5965            Some(
5966                buffer
5967                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5968                    .map(|entry| (entry.range, entry.diagnostic)),
5969            )
5970        })
5971        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5972    }
5973
5974    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
5975        &'a self,
5976        range: Range<T>,
5977    ) -> impl Iterator<Item = (BufferId, DiagnosticEntry<T>)> + 'a
5978    where
5979        T: 'a
5980            + text::ToOffset
5981            + text::FromAnchor
5982            + TextDimension
5983            + Ord
5984            + Sub<T, Output = T>
5985            + fmt::Debug,
5986    {
5987        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5988            Some(
5989                buffer
5990                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5991                    .map(|entry| (entry.range, entry.diagnostic)),
5992            )
5993        })
5994        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntry { diagnostic, range }))
5995    }
5996
5997    pub fn syntax_ancestor<T: ToOffset>(
5998        &self,
5999        range: Range<T>,
6000    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
6001        let range = range.start.to_offset(self)..range.end.to_offset(self);
6002        let mut excerpt = self.excerpt_containing(range.clone())?;
6003        let node = excerpt
6004            .buffer()
6005            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6006        let node_range = node.byte_range();
6007        let range = if excerpt.contains_buffer_range(node_range.clone()) {
6008            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
6009        } else {
6010            MultiOrSingleBufferOffsetRange::Single(node_range)
6011        };
6012        Some((node, range))
6013    }
6014
6015    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6016        let (excerpt_id, _, buffer) = self.as_singleton()?;
6017        let outline = buffer.outline(theme)?;
6018        Some(Outline::new(
6019            outline
6020                .items
6021                .into_iter()
6022                .flat_map(|item| {
6023                    Some(OutlineItem {
6024                        depth: item.depth,
6025                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
6026                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
6027                        text: item.text,
6028                        highlight_ranges: item.highlight_ranges,
6029                        name_ranges: item.name_ranges,
6030                        body_range: item.body_range.and_then(|body_range| {
6031                            Some(
6032                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
6033                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
6034                            )
6035                        }),
6036                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6037                            Some(
6038                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6039                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6040                            )
6041                        }),
6042                    })
6043                })
6044                .collect(),
6045        ))
6046    }
6047
6048    pub fn symbols_containing<T: ToOffset>(
6049        &self,
6050        offset: T,
6051        theme: Option<&SyntaxTheme>,
6052    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6053        let anchor = self.anchor_before(offset);
6054        let excerpt_id = anchor.excerpt_id;
6055        let excerpt = self.excerpt(excerpt_id)?;
6056        Some((
6057            excerpt.buffer_id,
6058            excerpt
6059                .buffer
6060                .symbols_containing(anchor.text_anchor, theme)
6061                .into_iter()
6062                .flatten()
6063                .flat_map(|item| {
6064                    Some(OutlineItem {
6065                        depth: item.depth,
6066                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6067                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6068                        text: item.text,
6069                        highlight_ranges: item.highlight_ranges,
6070                        name_ranges: item.name_ranges,
6071                        body_range: item.body_range.and_then(|body_range| {
6072                            Some(
6073                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6074                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6075                            )
6076                        }),
6077                        annotation_range: item.annotation_range.and_then(|body_range| {
6078                            Some(
6079                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6080                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6081                            )
6082                        }),
6083                    })
6084                })
6085                .collect(),
6086        ))
6087    }
6088
6089    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6090        if id == ExcerptId::min() {
6091            Locator::min_ref()
6092        } else if id == ExcerptId::max() {
6093            Locator::max_ref()
6094        } else {
6095            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6096            cursor.seek(&id, Bias::Left, &());
6097            if let Some(entry) = cursor.item() {
6098                if entry.id == id {
6099                    return &entry.locator;
6100                }
6101            }
6102            panic!("invalid excerpt id {id:?}")
6103        }
6104    }
6105
6106    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6107    fn excerpt_locators_for_ids(
6108        &self,
6109        ids: impl IntoIterator<Item = ExcerptId>,
6110    ) -> SmallVec<[Locator; 1]> {
6111        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6112        sorted_ids.sort_unstable();
6113        let mut locators = SmallVec::new();
6114
6115        while sorted_ids.last() == Some(&ExcerptId::max()) {
6116            sorted_ids.pop();
6117            if let Some(mapping) = self.excerpt_ids.last() {
6118                locators.push(mapping.locator.clone());
6119            }
6120        }
6121
6122        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6123        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6124            sorted_ids.next();
6125            if let Some(mapping) = self.excerpt_ids.first() {
6126                locators.push(mapping.locator.clone());
6127            }
6128        }
6129
6130        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6131        for id in sorted_ids {
6132            if cursor.seek_forward(&id, Bias::Left, &()) {
6133                locators.push(cursor.item().unwrap().locator.clone());
6134            } else {
6135                panic!("invalid excerpt id {:?}", id);
6136            }
6137        }
6138
6139        locators.sort_unstable();
6140        locators
6141    }
6142
6143    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6144        Some(self.excerpt(excerpt_id)?.buffer_id)
6145    }
6146
6147    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6148        Some(&self.excerpt(excerpt_id)?.buffer)
6149    }
6150
6151    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6152        let mut cursor = self
6153            .excerpts
6154            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6155        let locator = self.excerpt_locator_for_id(excerpt_id);
6156        if cursor.seek(&Some(locator), Bias::Left, &()) {
6157            let start = cursor.start().1.clone();
6158            let end = cursor.end(&()).1;
6159            let mut diff_transforms = self
6160                .diff_transforms
6161                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6162            diff_transforms.seek(&start, Bias::Left, &());
6163            let overshoot = start.0 - diff_transforms.start().0.0;
6164            let start = diff_transforms.start().1.0 + overshoot;
6165            diff_transforms.seek(&end, Bias::Right, &());
6166            let overshoot = end.0 - diff_transforms.start().0.0;
6167            let end = diff_transforms.start().1.0 + overshoot;
6168            Some(start..end)
6169        } else {
6170            None
6171        }
6172    }
6173
6174    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6175        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6176        let locator = self.excerpt_locator_for_id(excerpt_id);
6177        if cursor.seek(&Some(locator), Bias::Left, &()) {
6178            if let Some(excerpt) = cursor.item() {
6179                return Some(excerpt.range.context.clone());
6180            }
6181        }
6182        None
6183    }
6184
6185    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6186        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6187        let locator = self.excerpt_locator_for_id(excerpt_id);
6188        cursor.seek(&Some(locator), Bias::Left, &());
6189        if let Some(excerpt) = cursor.item() {
6190            if excerpt.id == excerpt_id {
6191                return Some(excerpt);
6192            }
6193        }
6194        None
6195    }
6196
6197    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6198    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
6199        let range = range.start.to_offset(self)..range.end.to_offset(self);
6200        let mut cursor = self.cursor::<usize>();
6201        cursor.seek(&range.start);
6202
6203        let start_excerpt = cursor.excerpt()?;
6204        if range.end != range.start {
6205            cursor.seek_forward(&range.end);
6206            if cursor.excerpt()?.id != start_excerpt.id {
6207                return None;
6208            }
6209        }
6210
6211        cursor.seek_to_start_of_current_excerpt();
6212        let region = cursor.region()?;
6213        let offset = region.range.start;
6214        let buffer_offset = region.buffer_range.start;
6215        let excerpt_offset = cursor.excerpts.start().clone();
6216        Some(MultiBufferExcerpt {
6217            diff_transforms: cursor.diff_transforms,
6218            excerpt: start_excerpt,
6219            offset,
6220            buffer_offset,
6221            excerpt_offset,
6222        })
6223    }
6224
6225    pub fn selections_in_range<'a>(
6226        &'a self,
6227        range: &'a Range<Anchor>,
6228        include_local: bool,
6229    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6230        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6231        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6232        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6233        cursor.seek(start_locator, Bias::Left, &());
6234        cursor
6235            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6236            .flat_map(move |excerpt| {
6237                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6238                if excerpt.id == range.start.excerpt_id {
6239                    query_range.start = range.start.text_anchor;
6240                }
6241                if excerpt.id == range.end.excerpt_id {
6242                    query_range.end = range.end.text_anchor;
6243                }
6244
6245                excerpt
6246                    .buffer
6247                    .selections_in_range(query_range, include_local)
6248                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6249                        selections.map(move |selection| {
6250                            let mut start = Anchor {
6251                                buffer_id: Some(excerpt.buffer_id),
6252                                excerpt_id: excerpt.id,
6253                                text_anchor: selection.start,
6254                                diff_base_anchor: None,
6255                            };
6256                            let mut end = Anchor {
6257                                buffer_id: Some(excerpt.buffer_id),
6258                                excerpt_id: excerpt.id,
6259                                text_anchor: selection.end,
6260                                diff_base_anchor: None,
6261                            };
6262                            if range.start.cmp(&start, self).is_gt() {
6263                                start = range.start;
6264                            }
6265                            if range.end.cmp(&end, self).is_lt() {
6266                                end = range.end;
6267                            }
6268
6269                            (
6270                                replica_id,
6271                                line_mode,
6272                                cursor_shape,
6273                                Selection {
6274                                    id: selection.id,
6275                                    start,
6276                                    end,
6277                                    reversed: selection.reversed,
6278                                    goal: selection.goal,
6279                                },
6280                            )
6281                        })
6282                    })
6283            })
6284    }
6285
6286    pub fn show_headers(&self) -> bool {
6287        self.show_headers
6288    }
6289
6290    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6291        self.diffs.get(&buffer_id)
6292    }
6293}
6294
6295#[cfg(any(test, feature = "test-support"))]
6296impl MultiBufferSnapshot {
6297    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6298        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6299        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6300        start..end
6301    }
6302
6303    #[cfg(any(test, feature = "test-support"))]
6304    fn check_invariants(&self) {
6305        let excerpts = self.excerpts.items(&());
6306        let excerpt_ids = self.excerpt_ids.items(&());
6307
6308        for (ix, excerpt) in excerpts.iter().enumerate() {
6309            if ix == 0 {
6310                if excerpt.locator <= Locator::min() {
6311                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6312                }
6313            } else if excerpt.locator <= excerpts[ix - 1].locator {
6314                panic!("excerpts are out-of-order: {:?}", excerpts);
6315            }
6316        }
6317
6318        for (ix, entry) in excerpt_ids.iter().enumerate() {
6319            if ix == 0 {
6320                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6321                    panic!("invalid first excerpt id {:?}", entry.id);
6322                }
6323            } else if entry.id <= excerpt_ids[ix - 1].id {
6324                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6325            }
6326        }
6327
6328        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6329            panic!(
6330                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6331                self.excerpts.summary().text.len,
6332                self.diff_transforms.summary().input,
6333                self.diff_transforms.items(&()),
6334            );
6335        }
6336
6337        let mut prev_transform: Option<&DiffTransform> = None;
6338        for item in self.diff_transforms.iter() {
6339            if let DiffTransform::BufferContent {
6340                summary,
6341                inserted_hunk_info,
6342            } = item
6343            {
6344                if let Some(DiffTransform::BufferContent {
6345                    inserted_hunk_info: prev_inserted_hunk_info,
6346                    ..
6347                }) = prev_transform
6348                {
6349                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6350                        panic!(
6351                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6352                            self.diff_transforms.items(&())
6353                        );
6354                    }
6355                }
6356                if summary.len == 0 && !self.is_empty() {
6357                    panic!("empty buffer content transform");
6358                }
6359            }
6360            prev_transform = Some(item);
6361        }
6362    }
6363}
6364
6365impl<'a, D> MultiBufferCursor<'a, D>
6366where
6367    D: TextDimension + Ord + Sub<D, Output = D>,
6368{
6369    fn seek(&mut self, position: &D) {
6370        self.cached_region.take();
6371        self.diff_transforms
6372            .seek(&OutputDimension(*position), Bias::Right, &());
6373        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6374            self.diff_transforms.prev(&());
6375        }
6376
6377        let mut excerpt_position = self.diff_transforms.start().1.0;
6378        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6379            let overshoot = *position - self.diff_transforms.start().0.0;
6380            excerpt_position.add_assign(&overshoot);
6381        }
6382
6383        self.excerpts
6384            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6385        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6386            self.excerpts.prev(&());
6387        }
6388    }
6389
6390    fn seek_forward(&mut self, position: &D) {
6391        self.cached_region.take();
6392        self.diff_transforms
6393            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6394        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6395            self.diff_transforms.prev(&());
6396        }
6397
6398        let overshoot = *position - self.diff_transforms.start().0.0;
6399        let mut excerpt_position = self.diff_transforms.start().1.0;
6400        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6401            excerpt_position.add_assign(&overshoot);
6402        }
6403
6404        self.excerpts
6405            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6406        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6407            self.excerpts.prev(&());
6408        }
6409    }
6410
6411    fn next_excerpt(&mut self) {
6412        self.excerpts.next(&());
6413        self.seek_to_start_of_current_excerpt();
6414    }
6415
6416    fn prev_excerpt(&mut self) {
6417        self.excerpts.prev(&());
6418        self.seek_to_start_of_current_excerpt();
6419    }
6420
6421    fn seek_to_start_of_current_excerpt(&mut self) {
6422        self.cached_region.take();
6423        self.diff_transforms
6424            .seek(self.excerpts.start(), Bias::Left, &());
6425        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6426            && self.diff_transforms.start().1 < *self.excerpts.start()
6427            && self.diff_transforms.next_item().is_some()
6428        {
6429            self.diff_transforms.next(&());
6430        }
6431    }
6432
6433    fn next(&mut self) {
6434        self.cached_region.take();
6435        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6436            cmp::Ordering::Less => self.diff_transforms.next(&()),
6437            cmp::Ordering::Greater => self.excerpts.next(&()),
6438            cmp::Ordering::Equal => {
6439                self.diff_transforms.next(&());
6440                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6441                    || self.diff_transforms.item().is_none()
6442                {
6443                    self.excerpts.next(&());
6444                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6445                    self.diff_transforms.item()
6446                {
6447                    if self
6448                        .excerpts
6449                        .item()
6450                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6451                    {
6452                        self.excerpts.next(&());
6453                    }
6454                }
6455            }
6456        }
6457    }
6458
6459    fn prev(&mut self) {
6460        self.cached_region.take();
6461        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6462            cmp::Ordering::Less => self.excerpts.prev(&()),
6463            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6464            cmp::Ordering::Equal => {
6465                self.diff_transforms.prev(&());
6466                if self.diff_transforms.start().1 < *self.excerpts.start()
6467                    || self.diff_transforms.item().is_none()
6468                {
6469                    self.excerpts.prev(&());
6470                }
6471            }
6472        }
6473    }
6474
6475    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6476        if self.cached_region.is_none() {
6477            self.cached_region = self.build_region();
6478        }
6479        self.cached_region.clone()
6480    }
6481
6482    fn is_at_start_of_excerpt(&mut self) -> bool {
6483        if self.diff_transforms.start().1 > *self.excerpts.start() {
6484            return false;
6485        } else if self.diff_transforms.start().1 < *self.excerpts.start() {
6486            return true;
6487        }
6488
6489        self.diff_transforms.prev(&());
6490        let prev_transform = self.diff_transforms.item();
6491        self.diff_transforms.next(&());
6492
6493        prev_transform.map_or(true, |next_transform| {
6494            matches!(next_transform, DiffTransform::BufferContent { .. })
6495        })
6496    }
6497
6498    fn is_at_end_of_excerpt(&mut self) -> bool {
6499        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6500            return false;
6501        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6502            || self.diff_transforms.item().is_none()
6503        {
6504            return true;
6505        }
6506
6507        let next_transform = self.diff_transforms.next_item();
6508        next_transform.map_or(true, |next_transform| match next_transform {
6509            DiffTransform::BufferContent { .. } => true,
6510            DiffTransform::DeletedHunk { hunk_info, .. } => self
6511                .excerpts
6512                .item()
6513                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6514        })
6515    }
6516
6517    fn main_buffer_position(&self) -> Option<D> {
6518        let excerpt = self.excerpts.item()?;
6519        let buffer = &excerpt.buffer;
6520        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6521        let mut buffer_start = buffer_context_start;
6522        let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6523        buffer_start.add_assign(&overshoot);
6524        Some(buffer_start)
6525    }
6526
6527    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6528        let excerpt = self.excerpts.item()?;
6529        match self.diff_transforms.item()? {
6530            DiffTransform::DeletedHunk {
6531                buffer_id,
6532                base_text_byte_range,
6533                has_trailing_newline,
6534                hunk_info,
6535                ..
6536            } => {
6537                let diff = self.diffs.get(&buffer_id)?;
6538                let buffer = diff.base_text();
6539                let mut rope_cursor = buffer.as_rope().cursor(0);
6540                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6541                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6542                let mut buffer_end = buffer_start;
6543                buffer_end.add_assign(&buffer_range_len);
6544                let start = self.diff_transforms.start().0.0;
6545                let end = self.diff_transforms.end(&()).0.0;
6546                return Some(MultiBufferRegion {
6547                    buffer,
6548                    excerpt,
6549                    has_trailing_newline: *has_trailing_newline,
6550                    is_main_buffer: false,
6551                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6552                        hunk_info.hunk_secondary_status,
6553                    )),
6554                    buffer_range: buffer_start..buffer_end,
6555                    range: start..end,
6556                });
6557            }
6558            DiffTransform::BufferContent {
6559                inserted_hunk_info, ..
6560            } => {
6561                let buffer = &excerpt.buffer;
6562                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6563
6564                let mut start = self.diff_transforms.start().0.0;
6565                let mut buffer_start = buffer_context_start;
6566                if self.diff_transforms.start().1 < *self.excerpts.start() {
6567                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1.0;
6568                    start.add_assign(&overshoot);
6569                } else {
6570                    let overshoot = self.diff_transforms.start().1.0 - self.excerpts.start().0;
6571                    buffer_start.add_assign(&overshoot);
6572                }
6573
6574                let mut end;
6575                let mut buffer_end;
6576                let has_trailing_newline;
6577                if self.diff_transforms.end(&()).1.0 < self.excerpts.end(&()).0 {
6578                    let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6579                    end = self.diff_transforms.end(&()).0.0;
6580                    buffer_end = buffer_context_start;
6581                    buffer_end.add_assign(&overshoot);
6582                    has_trailing_newline = false;
6583                } else {
6584                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1.0;
6585                    end = self.diff_transforms.start().0.0;
6586                    end.add_assign(&overshoot);
6587                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6588                    has_trailing_newline = excerpt.has_trailing_newline;
6589                };
6590
6591                Some(MultiBufferRegion {
6592                    buffer,
6593                    excerpt,
6594                    has_trailing_newline,
6595                    is_main_buffer: true,
6596                    diff_hunk_status: inserted_hunk_info
6597                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6598                    buffer_range: buffer_start..buffer_end,
6599                    range: start..end,
6600                })
6601            }
6602        }
6603    }
6604
6605    fn excerpt(&self) -> Option<&'a Excerpt> {
6606        self.excerpts.item()
6607    }
6608}
6609
6610impl History {
6611    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6612        self.transaction_depth += 1;
6613        if self.transaction_depth == 1 {
6614            let id = self.next_transaction_id.tick();
6615            self.undo_stack.push(Transaction {
6616                id,
6617                buffer_transactions: Default::default(),
6618                first_edit_at: now,
6619                last_edit_at: now,
6620                suppress_grouping: false,
6621            });
6622            Some(id)
6623        } else {
6624            None
6625        }
6626    }
6627
6628    fn end_transaction(
6629        &mut self,
6630        now: Instant,
6631        buffer_transactions: HashMap<BufferId, TransactionId>,
6632    ) -> bool {
6633        assert_ne!(self.transaction_depth, 0);
6634        self.transaction_depth -= 1;
6635        if self.transaction_depth == 0 {
6636            if buffer_transactions.is_empty() {
6637                self.undo_stack.pop();
6638                false
6639            } else {
6640                self.redo_stack.clear();
6641                let transaction = self.undo_stack.last_mut().unwrap();
6642                transaction.last_edit_at = now;
6643                for (buffer_id, transaction_id) in buffer_transactions {
6644                    transaction
6645                        .buffer_transactions
6646                        .entry(buffer_id)
6647                        .or_insert(transaction_id);
6648                }
6649                true
6650            }
6651        } else {
6652            false
6653        }
6654    }
6655
6656    fn push_transaction<'a, T>(
6657        &mut self,
6658        buffer_transactions: T,
6659        now: Instant,
6660        cx: &Context<MultiBuffer>,
6661    ) where
6662        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6663    {
6664        assert_eq!(self.transaction_depth, 0);
6665        let transaction = Transaction {
6666            id: self.next_transaction_id.tick(),
6667            buffer_transactions: buffer_transactions
6668                .into_iter()
6669                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6670                .collect(),
6671            first_edit_at: now,
6672            last_edit_at: now,
6673            suppress_grouping: false,
6674        };
6675        if !transaction.buffer_transactions.is_empty() {
6676            self.undo_stack.push(transaction);
6677            self.redo_stack.clear();
6678        }
6679    }
6680
6681    fn finalize_last_transaction(&mut self) {
6682        if let Some(transaction) = self.undo_stack.last_mut() {
6683            transaction.suppress_grouping = true;
6684        }
6685    }
6686
6687    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6688        if let Some(ix) = self
6689            .undo_stack
6690            .iter()
6691            .rposition(|transaction| transaction.id == transaction_id)
6692        {
6693            Some(self.undo_stack.remove(ix))
6694        } else if let Some(ix) = self
6695            .redo_stack
6696            .iter()
6697            .rposition(|transaction| transaction.id == transaction_id)
6698        {
6699            Some(self.redo_stack.remove(ix))
6700        } else {
6701            None
6702        }
6703    }
6704
6705    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6706        self.undo_stack
6707            .iter()
6708            .find(|transaction| transaction.id == transaction_id)
6709            .or_else(|| {
6710                self.redo_stack
6711                    .iter()
6712                    .find(|transaction| transaction.id == transaction_id)
6713            })
6714    }
6715
6716    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6717        self.undo_stack
6718            .iter_mut()
6719            .find(|transaction| transaction.id == transaction_id)
6720            .or_else(|| {
6721                self.redo_stack
6722                    .iter_mut()
6723                    .find(|transaction| transaction.id == transaction_id)
6724            })
6725    }
6726
6727    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6728        assert_eq!(self.transaction_depth, 0);
6729        if let Some(transaction) = self.undo_stack.pop() {
6730            self.redo_stack.push(transaction);
6731            self.redo_stack.last_mut()
6732        } else {
6733            None
6734        }
6735    }
6736
6737    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6738        assert_eq!(self.transaction_depth, 0);
6739        if let Some(transaction) = self.redo_stack.pop() {
6740            self.undo_stack.push(transaction);
6741            self.undo_stack.last_mut()
6742        } else {
6743            None
6744        }
6745    }
6746
6747    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6748        let ix = self
6749            .undo_stack
6750            .iter()
6751            .rposition(|transaction| transaction.id == transaction_id)?;
6752        let transaction = self.undo_stack.remove(ix);
6753        self.redo_stack.push(transaction);
6754        self.redo_stack.last()
6755    }
6756
6757    fn group(&mut self) -> Option<TransactionId> {
6758        let mut count = 0;
6759        let mut transactions = self.undo_stack.iter();
6760        if let Some(mut transaction) = transactions.next_back() {
6761            while let Some(prev_transaction) = transactions.next_back() {
6762                if !prev_transaction.suppress_grouping
6763                    && transaction.first_edit_at - prev_transaction.last_edit_at
6764                        <= self.group_interval
6765                {
6766                    transaction = prev_transaction;
6767                    count += 1;
6768                } else {
6769                    break;
6770                }
6771            }
6772        }
6773        self.group_trailing(count)
6774    }
6775
6776    fn group_until(&mut self, transaction_id: TransactionId) {
6777        let mut count = 0;
6778        for transaction in self.undo_stack.iter().rev() {
6779            if transaction.id == transaction_id {
6780                self.group_trailing(count);
6781                break;
6782            } else if transaction.suppress_grouping {
6783                break;
6784            } else {
6785                count += 1;
6786            }
6787        }
6788    }
6789
6790    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6791        let new_len = self.undo_stack.len() - n;
6792        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6793        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6794            if let Some(transaction) = transactions_to_merge.last() {
6795                last_transaction.last_edit_at = transaction.last_edit_at;
6796            }
6797            for to_merge in transactions_to_merge {
6798                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6799                    last_transaction
6800                        .buffer_transactions
6801                        .entry(*buffer_id)
6802                        .or_insert(*transaction_id);
6803                }
6804            }
6805        }
6806
6807        self.undo_stack.truncate(new_len);
6808        self.undo_stack.last().map(|t| t.id)
6809    }
6810}
6811
6812impl Excerpt {
6813    fn new(
6814        id: ExcerptId,
6815        locator: Locator,
6816        buffer_id: BufferId,
6817        buffer: BufferSnapshot,
6818        range: ExcerptRange<text::Anchor>,
6819        has_trailing_newline: bool,
6820    ) -> Self {
6821        Excerpt {
6822            id,
6823            locator,
6824            max_buffer_row: range.context.end.to_point(&buffer).row,
6825            text_summary: buffer
6826                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6827            buffer_id,
6828            buffer,
6829            range,
6830            has_trailing_newline,
6831        }
6832    }
6833
6834    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6835        let content_start = self.range.context.start.to_offset(&self.buffer);
6836        let chunks_start = content_start + range.start;
6837        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6838
6839        let footer_height = if self.has_trailing_newline
6840            && range.start <= self.text_summary.len
6841            && range.end > self.text_summary.len
6842        {
6843            1
6844        } else {
6845            0
6846        };
6847
6848        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6849
6850        ExcerptChunks {
6851            excerpt_id: self.id,
6852            content_chunks,
6853            footer_height,
6854        }
6855    }
6856
6857    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6858        let content_start = self.range.context.start.to_offset(&self.buffer);
6859        let chunks_start = content_start + range.start;
6860        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6861        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6862        excerpt_chunks.footer_height = if self.has_trailing_newline
6863            && range.start <= self.text_summary.len
6864            && range.end > self.text_summary.len
6865        {
6866            1
6867        } else {
6868            0
6869        };
6870    }
6871
6872    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6873        if text_anchor
6874            .cmp(&self.range.context.start, &self.buffer)
6875            .is_lt()
6876        {
6877            self.range.context.start
6878        } else if text_anchor
6879            .cmp(&self.range.context.end, &self.buffer)
6880            .is_gt()
6881        {
6882            self.range.context.end
6883        } else {
6884            text_anchor
6885        }
6886    }
6887
6888    fn contains(&self, anchor: &Anchor) -> bool {
6889        Some(self.buffer_id) == anchor.buffer_id
6890            && self
6891                .range
6892                .context
6893                .start
6894                .cmp(&anchor.text_anchor, &self.buffer)
6895                .is_le()
6896            && self
6897                .range
6898                .context
6899                .end
6900                .cmp(&anchor.text_anchor, &self.buffer)
6901                .is_ge()
6902    }
6903
6904    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6905    fn buffer_start_offset(&self) -> usize {
6906        self.range.context.start.to_offset(&self.buffer)
6907    }
6908
6909    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6910    fn buffer_end_offset(&self) -> usize {
6911        self.buffer_start_offset() + self.text_summary.len
6912    }
6913}
6914
6915impl<'a> MultiBufferExcerpt<'a> {
6916    pub fn id(&self) -> ExcerptId {
6917        self.excerpt.id
6918    }
6919
6920    pub fn buffer_id(&self) -> BufferId {
6921        self.excerpt.buffer_id
6922    }
6923
6924    pub fn start_anchor(&self) -> Anchor {
6925        Anchor {
6926            buffer_id: Some(self.excerpt.buffer_id),
6927            excerpt_id: self.excerpt.id,
6928            text_anchor: self.excerpt.range.context.start,
6929            diff_base_anchor: None,
6930        }
6931    }
6932
6933    pub fn end_anchor(&self) -> Anchor {
6934        Anchor {
6935            buffer_id: Some(self.excerpt.buffer_id),
6936            excerpt_id: self.excerpt.id,
6937            text_anchor: self.excerpt.range.context.end,
6938            diff_base_anchor: None,
6939        }
6940    }
6941
6942    pub fn buffer(&self) -> &'a BufferSnapshot {
6943        &self.excerpt.buffer
6944    }
6945
6946    pub fn buffer_range(&self) -> Range<usize> {
6947        self.buffer_offset
6948            ..self
6949                .excerpt
6950                .range
6951                .context
6952                .end
6953                .to_offset(&self.excerpt.buffer.text)
6954    }
6955
6956    pub fn start_offset(&self) -> usize {
6957        self.offset
6958    }
6959
6960    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6961    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6962        self.map_range_to_buffer(offset..offset).start
6963    }
6964
6965    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6966    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6967        self.diff_transforms
6968            .seek(&OutputDimension(range.start), Bias::Right, &());
6969        let start = self.map_offset_to_buffer_internal(range.start);
6970        let end = if range.end > range.start {
6971            self.diff_transforms
6972                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6973            self.map_offset_to_buffer_internal(range.end)
6974        } else {
6975            start
6976        };
6977        start..end
6978    }
6979
6980    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6981        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6982        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6983            excerpt_offset.0 += offset - self.diff_transforms.start().0.0;
6984        };
6985        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6986        self.buffer_offset + offset_in_excerpt
6987    }
6988
6989    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6990    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6991        self.map_range_from_buffer(buffer_offset..buffer_offset)
6992            .start
6993    }
6994
6995    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6996    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6997        if buffer_range.start < self.buffer_offset {
6998            log::warn!(
6999                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7000            );
7001            return buffer_range;
7002        }
7003        let overshoot = buffer_range.start - self.buffer_offset;
7004        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7005        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
7006        if excerpt_offset.0 < self.diff_transforms.start().1.0 {
7007            log::warn!(
7008                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7009            );
7010            return buffer_range;
7011        }
7012        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
7013        let start = self.diff_transforms.start().0.0 + overshoot;
7014
7015        let end = if buffer_range.end > buffer_range.start {
7016            let overshoot = buffer_range.end - self.buffer_offset;
7017            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7018            self.diff_transforms
7019                .seek_forward(&excerpt_offset, Bias::Right, &());
7020            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
7021            self.diff_transforms.start().0.0 + overshoot
7022        } else {
7023            start
7024        };
7025
7026        start..end
7027    }
7028
7029    /// Returns true if the entirety of the given range is in the buffer's excerpt
7030    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
7031        range.start >= self.excerpt.buffer_start_offset()
7032            && range.end <= self.excerpt.buffer_end_offset()
7033    }
7034
7035    pub fn max_buffer_row(&self) -> u32 {
7036        self.excerpt.max_buffer_row
7037    }
7038}
7039
7040impl ExcerptId {
7041    pub fn min() -> Self {
7042        Self(0)
7043    }
7044
7045    pub fn max() -> Self {
7046        Self(usize::MAX)
7047    }
7048
7049    pub fn to_proto(&self) -> u64 {
7050        self.0 as _
7051    }
7052
7053    pub fn from_proto(proto: u64) -> Self {
7054        Self(proto as _)
7055    }
7056
7057    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7058        let a = snapshot.excerpt_locator_for_id(*self);
7059        let b = snapshot.excerpt_locator_for_id(*other);
7060        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7061    }
7062}
7063
7064impl From<ExcerptId> for usize {
7065    fn from(val: ExcerptId) -> Self {
7066        val.0
7067    }
7068}
7069
7070impl fmt::Debug for Excerpt {
7071    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7072        f.debug_struct("Excerpt")
7073            .field("id", &self.id)
7074            .field("locator", &self.locator)
7075            .field("buffer_id", &self.buffer_id)
7076            .field("range", &self.range)
7077            .field("text_summary", &self.text_summary)
7078            .field("has_trailing_newline", &self.has_trailing_newline)
7079            .finish()
7080    }
7081}
7082
7083impl sum_tree::Item for Excerpt {
7084    type Summary = ExcerptSummary;
7085
7086    fn summary(&self, _cx: &()) -> Self::Summary {
7087        let mut text = self.text_summary;
7088        if self.has_trailing_newline {
7089            text += TextSummary::from("\n");
7090        }
7091        ExcerptSummary {
7092            excerpt_id: self.id,
7093            excerpt_locator: self.locator.clone(),
7094            widest_line_number: self.max_buffer_row,
7095            text,
7096        }
7097    }
7098}
7099
7100impl sum_tree::Item for ExcerptIdMapping {
7101    type Summary = ExcerptId;
7102
7103    fn summary(&self, _cx: &()) -> Self::Summary {
7104        self.id
7105    }
7106}
7107
7108impl sum_tree::KeyedItem for ExcerptIdMapping {
7109    type Key = ExcerptId;
7110
7111    fn key(&self) -> Self::Key {
7112        self.id
7113    }
7114}
7115
7116impl DiffTransform {
7117    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7118        match self {
7119            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7120            DiffTransform::BufferContent {
7121                inserted_hunk_info, ..
7122            } => *inserted_hunk_info,
7123        }
7124    }
7125}
7126
7127impl sum_tree::Item for DiffTransform {
7128    type Summary = DiffTransformSummary;
7129
7130    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7131        match self {
7132            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7133                input: *summary,
7134                output: *summary,
7135            },
7136            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7137                input: TextSummary::default(),
7138                output: *summary,
7139            },
7140        }
7141    }
7142}
7143
7144impl DiffTransformSummary {
7145    fn excerpt_len(&self) -> ExcerptOffset {
7146        ExcerptOffset::new(self.input.len)
7147    }
7148}
7149
7150impl sum_tree::Summary for DiffTransformSummary {
7151    type Context = ();
7152
7153    fn zero(_: &Self::Context) -> Self {
7154        DiffTransformSummary {
7155            input: TextSummary::default(),
7156            output: TextSummary::default(),
7157        }
7158    }
7159
7160    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7161        self.input += &summary.input;
7162        self.output += &summary.output;
7163    }
7164}
7165
7166impl sum_tree::Summary for ExcerptId {
7167    type Context = ();
7168
7169    fn zero(_cx: &()) -> Self {
7170        Default::default()
7171    }
7172
7173    fn add_summary(&mut self, other: &Self, _: &()) {
7174        *self = *other;
7175    }
7176}
7177
7178impl sum_tree::Summary for ExcerptSummary {
7179    type Context = ();
7180
7181    fn zero(_cx: &()) -> Self {
7182        Default::default()
7183    }
7184
7185    fn add_summary(&mut self, summary: &Self, _: &()) {
7186        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7187        self.excerpt_locator = summary.excerpt_locator.clone();
7188        self.text.add_summary(&summary.text, &());
7189        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7190    }
7191}
7192
7193impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7194    fn zero(_cx: &()) -> Self {
7195        Default::default()
7196    }
7197
7198    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7199        self.value += summary.text.len;
7200    }
7201}
7202
7203impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7204    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7205        Ord::cmp(&self.value, &cursor_location.text.len)
7206    }
7207}
7208
7209impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7210    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7211        Ord::cmp(&Some(self), cursor_location)
7212    }
7213}
7214
7215impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7216    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7217        Ord::cmp(self, &cursor_location.excerpt_locator)
7218    }
7219}
7220
7221impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7222    fn zero(_cx: &()) -> Self {
7223        Default::default()
7224    }
7225
7226    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7227        self.value += summary.text.lines;
7228    }
7229}
7230
7231impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7232    for ExcerptDimension<D>
7233{
7234    fn zero(_: &()) -> Self {
7235        ExcerptDimension(D::default())
7236    }
7237
7238    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7239        self.0.add_assign(&D::from_text_summary(&summary.text))
7240    }
7241}
7242
7243impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7244    fn zero(_cx: &()) -> Self {
7245        Default::default()
7246    }
7247
7248    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7249        *self = Some(&summary.excerpt_locator);
7250    }
7251}
7252
7253impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7254    fn zero(_cx: &()) -> Self {
7255        Default::default()
7256    }
7257
7258    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7259        *self = Some(summary.excerpt_id);
7260    }
7261}
7262
7263#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7264struct ExcerptDimension<T>(T);
7265
7266#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7267struct OutputDimension<T>(T);
7268
7269impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7270    fn zero(_: &()) -> Self {
7271        ExcerptOffset::new(0)
7272    }
7273
7274    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7275        self.value += summary.input.len;
7276    }
7277}
7278
7279impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7280    fn zero(_: &()) -> Self {
7281        ExcerptPoint::new(0, 0)
7282    }
7283
7284    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7285        self.value += summary.input.lines;
7286    }
7287}
7288
7289impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7290    for ExcerptDimension<D>
7291{
7292    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7293        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7294    }
7295}
7296
7297impl<D: TextDimension + Ord>
7298    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7299    for ExcerptDimension<D>
7300{
7301    fn cmp(
7302        &self,
7303        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7304        _: &(),
7305    ) -> cmp::Ordering {
7306        Ord::cmp(&self.0, &cursor_location.1.0)
7307    }
7308}
7309
7310impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7311    fn zero(_: &()) -> Self {
7312        ExcerptDimension(D::default())
7313    }
7314
7315    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7316        self.0.add_assign(&D::from_text_summary(&summary.input))
7317    }
7318}
7319
7320impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7321    fn zero(_: &()) -> Self {
7322        OutputDimension(D::default())
7323    }
7324
7325    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7326        self.0.add_assign(&D::from_text_summary(&summary.output))
7327    }
7328}
7329
7330impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7331    fn zero(_: &()) -> Self {
7332        TextSummary::default()
7333    }
7334
7335    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7336        *self += summary.output
7337    }
7338}
7339
7340impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7341    fn zero(_: &()) -> Self {
7342        0
7343    }
7344
7345    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7346        *self += summary.output.len
7347    }
7348}
7349
7350impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7351    fn zero(_: &()) -> Self {
7352        Point::new(0, 0)
7353    }
7354
7355    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7356        *self += summary.output.lines
7357    }
7358}
7359
7360impl MultiBufferRows<'_> {
7361    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7362        self.point = Point::new(row, 0);
7363        self.cursor.seek(&self.point);
7364    }
7365}
7366
7367impl Iterator for MultiBufferRows<'_> {
7368    type Item = RowInfo;
7369
7370    fn next(&mut self) -> Option<Self::Item> {
7371        if self.is_empty && self.point.row == 0 {
7372            self.point += Point::new(1, 0);
7373            return Some(RowInfo {
7374                buffer_id: None,
7375                buffer_row: Some(0),
7376                multibuffer_row: Some(MultiBufferRow(0)),
7377                diff_status: None,
7378                expand_info: None,
7379            });
7380        }
7381
7382        let mut region = self.cursor.region()?;
7383        while self.point >= region.range.end {
7384            self.cursor.next();
7385            if let Some(next_region) = self.cursor.region() {
7386                region = next_region;
7387            } else {
7388                if self.point == self.cursor.diff_transforms.end(&()).0.0 {
7389                    let multibuffer_row = MultiBufferRow(self.point.row);
7390                    let last_excerpt = self
7391                        .cursor
7392                        .excerpts
7393                        .item()
7394                        .or(self.cursor.excerpts.prev_item())?;
7395                    let last_row = last_excerpt
7396                        .range
7397                        .context
7398                        .end
7399                        .to_point(&last_excerpt.buffer)
7400                        .row;
7401
7402                    let first_row = last_excerpt
7403                        .range
7404                        .context
7405                        .start
7406                        .to_point(&last_excerpt.buffer)
7407                        .row;
7408
7409                    let expand_info = if self.is_singleton {
7410                        None
7411                    } else {
7412                        let needs_expand_up = first_row == last_row
7413                            && last_row > 0
7414                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7415                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7416
7417                        if needs_expand_up && needs_expand_down {
7418                            Some(ExpandExcerptDirection::UpAndDown)
7419                        } else if needs_expand_up {
7420                            Some(ExpandExcerptDirection::Up)
7421                        } else if needs_expand_down {
7422                            Some(ExpandExcerptDirection::Down)
7423                        } else {
7424                            None
7425                        }
7426                        .map(|direction| ExpandInfo {
7427                            direction,
7428                            excerpt_id: last_excerpt.id,
7429                        })
7430                    };
7431                    self.point += Point::new(1, 0);
7432                    return Some(RowInfo {
7433                        buffer_id: Some(last_excerpt.buffer_id),
7434                        buffer_row: Some(last_row),
7435                        multibuffer_row: Some(multibuffer_row),
7436                        diff_status: None,
7437                        expand_info,
7438                    });
7439                } else {
7440                    return None;
7441                }
7442            };
7443        }
7444
7445        let overshoot = self.point - region.range.start;
7446        let buffer_point = region.buffer_range.start + overshoot;
7447        let expand_info = if self.is_singleton {
7448            None
7449        } else {
7450            let needs_expand_up = self.point.row == region.range.start.row
7451                && self.cursor.is_at_start_of_excerpt()
7452                && buffer_point.row > 0;
7453            let needs_expand_down = (region.excerpt.has_trailing_newline
7454                && self.point.row + 1 == region.range.end.row
7455                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7456                && self.cursor.is_at_end_of_excerpt()
7457                && buffer_point.row < region.buffer.max_point().row;
7458
7459            if needs_expand_up && needs_expand_down {
7460                Some(ExpandExcerptDirection::UpAndDown)
7461            } else if needs_expand_up {
7462                Some(ExpandExcerptDirection::Up)
7463            } else if needs_expand_down {
7464                Some(ExpandExcerptDirection::Down)
7465            } else {
7466                None
7467            }
7468            .map(|direction| ExpandInfo {
7469                direction,
7470                excerpt_id: region.excerpt.id,
7471            })
7472        };
7473
7474        let result = Some(RowInfo {
7475            buffer_id: Some(region.buffer.remote_id()),
7476            buffer_row: Some(buffer_point.row),
7477            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7478            diff_status: region
7479                .diff_hunk_status
7480                .filter(|_| self.point < region.range.end),
7481            expand_info,
7482        });
7483        self.point += Point::new(1, 0);
7484        result
7485    }
7486}
7487
7488impl<'a> MultiBufferChunks<'a> {
7489    pub fn offset(&self) -> usize {
7490        self.range.start
7491    }
7492
7493    pub fn seek(&mut self, range: Range<usize>) {
7494        self.diff_transforms.seek(&range.end, Bias::Right, &());
7495        let mut excerpt_end = self.diff_transforms.start().1;
7496        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7497            let overshoot = range.end - self.diff_transforms.start().0;
7498            excerpt_end.value += overshoot;
7499        }
7500
7501        self.diff_transforms.seek(&range.start, Bias::Right, &());
7502        let mut excerpt_start = self.diff_transforms.start().1;
7503        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7504            let overshoot = range.start - self.diff_transforms.start().0;
7505            excerpt_start.value += overshoot;
7506        }
7507
7508        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7509        self.buffer_chunk.take();
7510        self.range = range;
7511    }
7512
7513    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7514        self.excerpt_offset_range = new_range.clone();
7515        self.excerpts.seek(&new_range.start, Bias::Right, &());
7516        if let Some(excerpt) = self.excerpts.item() {
7517            let excerpt_start = *self.excerpts.start();
7518            if let Some(excerpt_chunks) = self
7519                .excerpt_chunks
7520                .as_mut()
7521                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7522            {
7523                excerpt.seek_chunks(
7524                    excerpt_chunks,
7525                    (self.excerpt_offset_range.start - excerpt_start).value
7526                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7527                );
7528            } else {
7529                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7530                    (self.excerpt_offset_range.start - excerpt_start).value
7531                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7532                    self.language_aware,
7533                ));
7534            }
7535        } else {
7536            self.excerpt_chunks = None;
7537        }
7538    }
7539
7540    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7541        loop {
7542            if self.excerpt_offset_range.is_empty() {
7543                return None;
7544            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7545                self.excerpt_offset_range.start.value += chunk.text.len();
7546                return Some(chunk);
7547            } else {
7548                self.excerpts.next(&());
7549                let excerpt = self.excerpts.item()?;
7550                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7551                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7552                    self.language_aware,
7553                ));
7554            }
7555        }
7556    }
7557}
7558
7559impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7560    type Item = &'a str;
7561
7562    fn next(&mut self) -> Option<Self::Item> {
7563        let mut region = self.cursor.region()?;
7564        if self.offset == region.range.start {
7565            self.cursor.prev();
7566            region = self.cursor.region()?;
7567            let start_overshoot = self.start.saturating_sub(region.range.start);
7568            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7569                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7570            ));
7571        }
7572
7573        if self.offset == region.range.end && region.has_trailing_newline {
7574            self.offset -= 1;
7575            Some("\n")
7576        } else {
7577            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7578            self.offset -= chunk.len();
7579            Some(chunk)
7580        }
7581    }
7582}
7583
7584impl<'a> Iterator for MultiBufferChunks<'a> {
7585    type Item = Chunk<'a>;
7586
7587    fn next(&mut self) -> Option<Chunk<'a>> {
7588        if self.range.start >= self.range.end {
7589            return None;
7590        }
7591        if self.range.start == self.diff_transforms.end(&()).0 {
7592            self.diff_transforms.next(&());
7593        }
7594
7595        let diff_transform_start = self.diff_transforms.start().0;
7596        let diff_transform_end = self.diff_transforms.end(&()).0;
7597        debug_assert!(self.range.start < diff_transform_end);
7598
7599        let diff_transform = self.diff_transforms.item()?;
7600        match diff_transform {
7601            DiffTransform::BufferContent { .. } => {
7602                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7603                    chunk
7604                } else {
7605                    let chunk = self.next_excerpt_chunk().unwrap();
7606                    self.buffer_chunk.insert(chunk)
7607                };
7608
7609                let chunk_end = self.range.start + chunk.text.len();
7610                let diff_transform_end = diff_transform_end.min(self.range.end);
7611
7612                if diff_transform_end < chunk_end {
7613                    let (before, after) =
7614                        chunk.text.split_at(diff_transform_end - self.range.start);
7615                    self.range.start = diff_transform_end;
7616                    chunk.text = after;
7617                    Some(Chunk {
7618                        text: before,
7619                        ..chunk.clone()
7620                    })
7621                } else {
7622                    self.range.start = chunk_end;
7623                    self.buffer_chunk.take()
7624                }
7625            }
7626            DiffTransform::DeletedHunk {
7627                buffer_id,
7628                base_text_byte_range,
7629                has_trailing_newline,
7630                ..
7631            } => {
7632                let base_text_start =
7633                    base_text_byte_range.start + self.range.start - diff_transform_start;
7634                let base_text_end =
7635                    base_text_byte_range.start + self.range.end - diff_transform_start;
7636                let base_text_end = base_text_end.min(base_text_byte_range.end);
7637
7638                let mut chunks = if let Some((_, mut chunks)) = self
7639                    .diff_base_chunks
7640                    .take()
7641                    .filter(|(id, _)| id == buffer_id)
7642                {
7643                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7644                    {
7645                        chunks.seek(base_text_start..base_text_end);
7646                    }
7647                    chunks
7648                } else {
7649                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7650                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7651                };
7652
7653                let chunk = if let Some(chunk) = chunks.next() {
7654                    self.range.start += chunk.text.len();
7655                    self.diff_base_chunks = Some((*buffer_id, chunks));
7656                    chunk
7657                } else {
7658                    debug_assert!(has_trailing_newline);
7659                    self.range.start += "\n".len();
7660                    Chunk {
7661                        text: "\n",
7662                        ..Default::default()
7663                    }
7664                };
7665                Some(chunk)
7666            }
7667        }
7668    }
7669}
7670
7671impl MultiBufferBytes<'_> {
7672    fn consume(&mut self, len: usize) {
7673        self.range.start += len;
7674        self.chunk = &self.chunk[len..];
7675
7676        if !self.range.is_empty() && self.chunk.is_empty() {
7677            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7678                self.chunk = chunk;
7679            } else if self.has_trailing_newline {
7680                self.has_trailing_newline = false;
7681                self.chunk = b"\n";
7682            } else {
7683                self.cursor.next();
7684                if let Some(region) = self.cursor.region() {
7685                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7686                        region.buffer_range.start
7687                            ..(region.buffer_range.start + self.range.end - region.range.start)
7688                                .min(region.buffer_range.end),
7689                    );
7690                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7691                    self.excerpt_bytes = Some(excerpt_bytes);
7692                    self.has_trailing_newline =
7693                        region.has_trailing_newline && self.range.end >= region.range.end;
7694                    if self.chunk.is_empty() && self.has_trailing_newline {
7695                        self.has_trailing_newline = false;
7696                        self.chunk = b"\n";
7697                    }
7698                }
7699            }
7700        }
7701    }
7702}
7703
7704impl<'a> Iterator for MultiBufferBytes<'a> {
7705    type Item = &'a [u8];
7706
7707    fn next(&mut self) -> Option<Self::Item> {
7708        let chunk = self.chunk;
7709        if chunk.is_empty() {
7710            None
7711        } else {
7712            self.consume(chunk.len());
7713            Some(chunk)
7714        }
7715    }
7716}
7717
7718impl io::Read for MultiBufferBytes<'_> {
7719    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7720        let len = cmp::min(buf.len(), self.chunk.len());
7721        buf[..len].copy_from_slice(&self.chunk[..len]);
7722        if len > 0 {
7723            self.consume(len);
7724        }
7725        Ok(len)
7726    }
7727}
7728
7729impl io::Read for ReversedMultiBufferBytes<'_> {
7730    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7731        let len = cmp::min(buf.len(), self.chunk.len());
7732        buf[..len].copy_from_slice(&self.chunk[..len]);
7733        buf[..len].reverse();
7734        if len > 0 {
7735            self.range.end -= len;
7736            self.chunk = &self.chunk[..self.chunk.len() - len];
7737            if !self.range.is_empty() && self.chunk.is_empty() {
7738                if let Some(chunk) = self.chunks.next() {
7739                    self.chunk = chunk.as_bytes();
7740                }
7741            }
7742        }
7743        Ok(len)
7744    }
7745}
7746
7747impl<'a> Iterator for ExcerptChunks<'a> {
7748    type Item = Chunk<'a>;
7749
7750    fn next(&mut self) -> Option<Self::Item> {
7751        if let Some(chunk) = self.content_chunks.next() {
7752            return Some(chunk);
7753        }
7754
7755        if self.footer_height > 0 {
7756            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7757            self.footer_height = 0;
7758            return Some(Chunk {
7759                text,
7760                ..Default::default()
7761            });
7762        }
7763
7764        None
7765    }
7766}
7767
7768impl ToOffset for Point {
7769    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7770        snapshot.point_to_offset(*self)
7771    }
7772}
7773
7774impl ToOffset for usize {
7775    #[track_caller]
7776    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7777        assert!(
7778            *self <= snapshot.len(),
7779            "offset {} is greater than the snapshot.len() {}",
7780            *self,
7781            snapshot.len(),
7782        );
7783        *self
7784    }
7785}
7786
7787impl ToOffset for OffsetUtf16 {
7788    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7789        snapshot.offset_utf16_to_offset(*self)
7790    }
7791}
7792
7793impl ToOffset for PointUtf16 {
7794    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7795        snapshot.point_utf16_to_offset(*self)
7796    }
7797}
7798
7799impl ToOffsetUtf16 for OffsetUtf16 {
7800    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7801        *self
7802    }
7803}
7804
7805impl ToOffsetUtf16 for usize {
7806    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7807        snapshot.offset_to_offset_utf16(*self)
7808    }
7809}
7810
7811impl ToPoint for usize {
7812    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7813        snapshot.offset_to_point(*self)
7814    }
7815}
7816
7817impl ToPoint for Point {
7818    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7819        *self
7820    }
7821}
7822
7823impl ToPointUtf16 for usize {
7824    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7825        snapshot.offset_to_point_utf16(*self)
7826    }
7827}
7828
7829impl ToPointUtf16 for Point {
7830    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7831        snapshot.point_to_point_utf16(*self)
7832    }
7833}
7834
7835impl ToPointUtf16 for PointUtf16 {
7836    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7837        *self
7838    }
7839}
7840
7841impl From<ExcerptId> for EntityId {
7842    fn from(id: ExcerptId) -> Self {
7843        EntityId::from(id.0 as u64)
7844    }
7845}