multi_buffer.rs

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