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