multi_buffer.rs

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