multi_buffer.rs

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