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