multi_buffer.rs

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