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<MultiBufferRow> {
3802        let offset = position.to_offset(self);
3803
3804        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3805        cursor.seek(&DimensionPair {
3806            key: offset,
3807            value: None,
3808        });
3809        cursor.seek_to_start_of_current_excerpt();
3810        let excerpt = cursor.excerpt()?;
3811
3812        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3813        let current_position = self
3814            .anchor_before(offset)
3815            .text_anchor
3816            .to_offset(&excerpt.buffer);
3817        let excerpt_end = excerpt
3818            .buffer
3819            .anchor_before(excerpt_end.min(current_position));
3820
3821        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3822            for hunk in diff.hunks_intersecting_range_rev(
3823                excerpt.range.context.start..excerpt_end,
3824                &excerpt.buffer,
3825            ) {
3826                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3827                if hunk_end >= current_position {
3828                    continue;
3829                }
3830                let start =
3831                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3832                        .to_point(&self);
3833                return Some(MultiBufferRow(start.row));
3834            }
3835        }
3836
3837        loop {
3838            cursor.prev_excerpt();
3839            let excerpt = cursor.excerpt()?;
3840
3841            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3842                continue;
3843            };
3844            let mut hunks =
3845                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3846            let Some(hunk) = hunks.next() else {
3847                continue;
3848            };
3849            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3850                .to_point(&self);
3851            return Some(MultiBufferRow(start.row));
3852        }
3853    }
3854
3855    pub fn has_diff_hunks(&self) -> bool {
3856        self.diffs.values().any(|diff| !diff.is_empty())
3857    }
3858
3859    pub fn surrounding_word<T: ToOffset>(
3860        &self,
3861        start: T,
3862        for_completion: bool,
3863    ) -> (Range<usize>, Option<CharKind>) {
3864        let mut start = start.to_offset(self);
3865        let mut end = start;
3866        let mut next_chars = self.chars_at(start).peekable();
3867        let mut prev_chars = self.reversed_chars_at(start).peekable();
3868
3869        let classifier = self
3870            .char_classifier_at(start)
3871            .for_completion(for_completion);
3872
3873        let word_kind = cmp::max(
3874            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3875            next_chars.peek().copied().map(|c| classifier.kind(c)),
3876        );
3877
3878        for ch in prev_chars {
3879            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3880                start -= ch.len_utf8();
3881            } else {
3882                break;
3883            }
3884        }
3885
3886        for ch in next_chars {
3887            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3888                end += ch.len_utf8();
3889            } else {
3890                break;
3891            }
3892        }
3893
3894        (start..end, word_kind)
3895    }
3896
3897    pub fn is_singleton(&self) -> bool {
3898        self.singleton
3899    }
3900
3901    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3902        if self.singleton {
3903            self.excerpts
3904                .iter()
3905                .next()
3906                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3907        } else {
3908            None
3909        }
3910    }
3911
3912    pub fn len(&self) -> usize {
3913        self.diff_transforms.summary().output.len
3914    }
3915
3916    pub fn is_empty(&self) -> bool {
3917        self.excerpts.summary().text.len == 0
3918    }
3919
3920    pub fn widest_line_number(&self) -> u32 {
3921        self.excerpts.summary().widest_line_number + 1
3922    }
3923
3924    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3925        let range = range.start.to_offset(self)..range.end.to_offset(self);
3926        let mut excerpts = self.cursor::<usize>();
3927        excerpts.seek(&range.start);
3928
3929        let mut chunk;
3930        let mut has_trailing_newline;
3931        let excerpt_bytes;
3932        if let Some(region) = excerpts.region() {
3933            let mut bytes = region.buffer.bytes_in_range(
3934                region.buffer_range.start + range.start - region.range.start
3935                    ..(region.buffer_range.start + range.end - region.range.start)
3936                        .min(region.buffer_range.end),
3937            );
3938            chunk = bytes.next().unwrap_or(&[][..]);
3939            excerpt_bytes = Some(bytes);
3940            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3941            if chunk.is_empty() && has_trailing_newline {
3942                chunk = b"\n";
3943                has_trailing_newline = false;
3944            }
3945        } else {
3946            chunk = &[][..];
3947            excerpt_bytes = None;
3948            has_trailing_newline = false;
3949        };
3950
3951        MultiBufferBytes {
3952            range,
3953            cursor: excerpts,
3954            excerpt_bytes,
3955            has_trailing_newline,
3956            chunk,
3957        }
3958    }
3959
3960    pub fn reversed_bytes_in_range<T: ToOffset>(
3961        &self,
3962        range: Range<T>,
3963    ) -> ReversedMultiBufferBytes {
3964        let range = range.start.to_offset(self)..range.end.to_offset(self);
3965        let mut chunks = self.reversed_chunks_in_range(range.clone());
3966        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3967        ReversedMultiBufferBytes {
3968            range,
3969            chunks,
3970            chunk,
3971        }
3972    }
3973
3974    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3975        let mut cursor = self.cursor::<Point>();
3976        cursor.seek(&Point::new(start_row.0, 0));
3977        let mut result = MultiBufferRows {
3978            point: Point::new(0, 0),
3979            is_empty: self.excerpts.is_empty(),
3980            cursor,
3981        };
3982        result.seek(start_row);
3983        result
3984    }
3985
3986    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3987        let mut chunks = MultiBufferChunks {
3988            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3989            range: 0..0,
3990            excerpts: self.excerpts.cursor(&()),
3991            diff_transforms: self.diff_transforms.cursor(&()),
3992            diffs: &self.diffs,
3993            diff_base_chunks: None,
3994            excerpt_chunks: None,
3995            buffer_chunk: None,
3996            language_aware,
3997        };
3998        let range = range.start.to_offset(self)..range.end.to_offset(self);
3999        chunks.seek(range);
4000        chunks
4001    }
4002
4003    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4004        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4005    }
4006
4007    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4008        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4009    }
4010
4011    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4012        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4013    }
4014
4015    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4016        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4017            buffer.clip_point_utf16(Unclipped(point), bias)
4018        })
4019    }
4020
4021    pub fn offset_to_point(&self, offset: usize) -> Point {
4022        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4023    }
4024
4025    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4026        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4027    }
4028
4029    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4030        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4031    }
4032
4033    pub fn point_to_offset(&self, point: Point) -> usize {
4034        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4035    }
4036
4037    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4038        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4039    }
4040
4041    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4042        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4043    }
4044
4045    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4046        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4047    }
4048
4049    fn clip_dimension<D>(
4050        &self,
4051        position: D,
4052        bias: Bias,
4053        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4054    ) -> D
4055    where
4056        D: TextDimension + Ord + Sub<D, Output = D>,
4057    {
4058        let mut cursor = self.cursor();
4059        cursor.seek(&position);
4060        if let Some(region) = cursor.region() {
4061            if position >= region.range.end {
4062                return region.range.end;
4063            }
4064            let overshoot = position - region.range.start;
4065            let mut buffer_position = region.buffer_range.start;
4066            buffer_position.add_assign(&overshoot);
4067            let clipped_buffer_position =
4068                clip_buffer_position(&region.buffer, buffer_position, bias);
4069            let mut position = region.range.start;
4070            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4071            position
4072        } else {
4073            D::from_text_summary(&self.text_summary())
4074        }
4075    }
4076
4077    fn convert_dimension<D1, D2>(
4078        &self,
4079        key: D1,
4080        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4081    ) -> D2
4082    where
4083        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4084        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4085    {
4086        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4087        cursor.seek(&DimensionPair { key, value: None });
4088        if let Some(region) = cursor.region() {
4089            if key >= region.range.end.key {
4090                return region.range.end.value.unwrap();
4091            }
4092            let start_key = region.range.start.key;
4093            let start_value = region.range.start.value.unwrap();
4094            let buffer_start_key = region.buffer_range.start.key;
4095            let buffer_start_value = region.buffer_range.start.value.unwrap();
4096            let mut buffer_key = buffer_start_key;
4097            buffer_key.add_assign(&(key - start_key));
4098            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4099            let mut result = start_value;
4100            result.add_assign(&(buffer_value - buffer_start_value));
4101            result
4102        } else {
4103            D2::from_text_summary(&self.text_summary())
4104        }
4105    }
4106
4107    pub fn point_to_buffer_offset<T: ToOffset>(
4108        &self,
4109        point: T,
4110    ) -> Option<(&BufferSnapshot, usize)> {
4111        let offset = point.to_offset(self);
4112        let mut cursor = self.cursor::<usize>();
4113        cursor.seek(&offset);
4114        let region = cursor.region()?;
4115        let overshoot = offset - region.range.start;
4116        let buffer_offset = region.buffer_range.start + overshoot;
4117        Some((region.buffer, buffer_offset))
4118    }
4119
4120    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4121        let mut cursor = self.cursor::<Point>();
4122        cursor.seek(&point);
4123        let region = cursor.region()?;
4124        let overshoot = point - region.range.start;
4125        let buffer_offset = region.buffer_range.start + overshoot;
4126        Some((region.buffer, buffer_offset, region.is_main_buffer))
4127    }
4128
4129    pub fn suggested_indents(
4130        &self,
4131        rows: impl IntoIterator<Item = u32>,
4132        cx: &App,
4133    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4134        let mut result = BTreeMap::new();
4135
4136        let mut rows_for_excerpt = Vec::new();
4137        let mut cursor = self.cursor::<Point>();
4138        let mut rows = rows.into_iter().peekable();
4139        let mut prev_row = u32::MAX;
4140        let mut prev_language_indent_size = IndentSize::default();
4141
4142        while let Some(row) = rows.next() {
4143            cursor.seek(&Point::new(row, 0));
4144            let Some(region) = cursor.region() else {
4145                continue;
4146            };
4147
4148            // Retrieve the language and indent size once for each disjoint region being indented.
4149            let single_indent_size = if row.saturating_sub(1) == prev_row {
4150                prev_language_indent_size
4151            } else {
4152                region
4153                    .buffer
4154                    .language_indent_size_at(Point::new(row, 0), cx)
4155            };
4156            prev_language_indent_size = single_indent_size;
4157            prev_row = row;
4158
4159            let start_buffer_row = region.buffer_range.start.row;
4160            let start_multibuffer_row = region.range.start.row;
4161            let end_multibuffer_row = region.range.end.row;
4162
4163            rows_for_excerpt.push(row);
4164            while let Some(next_row) = rows.peek().copied() {
4165                if end_multibuffer_row > next_row {
4166                    rows_for_excerpt.push(next_row);
4167                    rows.next();
4168                } else {
4169                    break;
4170                }
4171            }
4172
4173            let buffer_rows = rows_for_excerpt
4174                .drain(..)
4175                .map(|row| start_buffer_row + row - start_multibuffer_row);
4176            let buffer_indents = region
4177                .buffer
4178                .suggested_indents(buffer_rows, single_indent_size);
4179            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4180                (
4181                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4182                    indent,
4183                )
4184            });
4185            result.extend(multibuffer_indents);
4186        }
4187
4188        result
4189    }
4190
4191    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4192        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4193            let mut size = buffer.indent_size_for_line(range.start.row);
4194            size.len = size
4195                .len
4196                .min(range.end.column)
4197                .saturating_sub(range.start.column);
4198            size
4199        } else {
4200            IndentSize::spaces(0)
4201        }
4202    }
4203
4204    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4205        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4206            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4207        } else {
4208            LineIndent::spaces(0)
4209        }
4210    }
4211
4212    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4213        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4214
4215        if self.settings_at(0, cx).extend_comment_on_newline {
4216            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4217                let delimiters = language_scope.line_comment_prefixes();
4218                for delimiter in delimiters {
4219                    if *self
4220                        .chars_at(Point::new(row.0, indent.len() as u32))
4221                        .take(delimiter.chars().count())
4222                        .collect::<String>()
4223                        .as_str()
4224                        == **delimiter
4225                    {
4226                        indent.push_str(&delimiter);
4227                        break;
4228                    }
4229                }
4230            }
4231        }
4232
4233        indent
4234    }
4235
4236    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4237    where
4238        T: ToOffset,
4239    {
4240        for char in self.reversed_chars_at(position) {
4241            if !char.is_whitespace() {
4242                return false;
4243            }
4244            if char == '\n' {
4245                return true;
4246            }
4247        }
4248        return true;
4249    }
4250
4251    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4252        while row.0 > 0 {
4253            row.0 -= 1;
4254            if !self.is_line_blank(row) {
4255                return Some(row);
4256            }
4257        }
4258        None
4259    }
4260
4261    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4262        if let Some((_, range)) = self.buffer_line_for_row(row) {
4263            range.end.column - range.start.column
4264        } else {
4265            0
4266        }
4267    }
4268
4269    pub fn buffer_line_for_row(
4270        &self,
4271        row: MultiBufferRow,
4272    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4273        let mut cursor = self.cursor::<Point>();
4274        let point = Point::new(row.0, 0);
4275        cursor.seek(&point);
4276        let region = cursor.region()?;
4277        let overshoot = point.min(region.range.end) - region.range.start;
4278        let buffer_point = region.buffer_range.start + overshoot;
4279        if buffer_point.row > region.buffer_range.end.row {
4280            return None;
4281        }
4282        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4283        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4284            .min(region.buffer_range.end);
4285        Some((region.buffer, line_start..line_end))
4286    }
4287
4288    pub fn max_point(&self) -> Point {
4289        self.text_summary().lines
4290    }
4291
4292    pub fn max_row(&self) -> MultiBufferRow {
4293        MultiBufferRow(self.text_summary().lines.row)
4294    }
4295
4296    pub fn text_summary(&self) -> TextSummary {
4297        self.diff_transforms.summary().output
4298    }
4299
4300    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4301    where
4302        D: TextDimension,
4303        O: ToOffset,
4304    {
4305        let range = range.start.to_offset(self)..range.end.to_offset(self);
4306        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4307        cursor.seek(&range.start, Bias::Right, &());
4308
4309        let Some(first_transform) = cursor.item() else {
4310            return D::from_text_summary(&TextSummary::default());
4311        };
4312
4313        let diff_transform_start = cursor.start().0;
4314        let diff_transform_end = cursor.end(&()).0;
4315        let diff_start = range.start;
4316        let start_overshoot = diff_start - diff_transform_start;
4317        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4318
4319        let mut result = match first_transform {
4320            DiffTransform::BufferContent { .. } => {
4321                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4322                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4323                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4324            }
4325            DiffTransform::DeletedHunk {
4326                buffer_id,
4327                base_text_byte_range,
4328                has_trailing_newline,
4329                ..
4330            } => {
4331                let buffer_start = base_text_byte_range.start + start_overshoot;
4332                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4333                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4334                    panic!("{:?} is in non-existent deleted hunk", range.start)
4335                };
4336
4337                let include_trailing_newline =
4338                    *has_trailing_newline && range.end >= diff_transform_end;
4339                if include_trailing_newline {
4340                    buffer_end -= 1;
4341                }
4342
4343                let mut summary =
4344                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4345
4346                if include_trailing_newline {
4347                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4348                }
4349
4350                summary
4351            }
4352        };
4353        if range.end < diff_transform_end {
4354            return result;
4355        }
4356
4357        cursor.next(&());
4358        result.add_assign(&D::from_text_summary(&cursor.summary(
4359            &range.end,
4360            Bias::Right,
4361            &(),
4362        )));
4363
4364        let Some(last_transform) = cursor.item() else {
4365            return result;
4366        };
4367
4368        let overshoot = range.end - cursor.start().0;
4369        let suffix = match last_transform {
4370            DiffTransform::BufferContent { .. } => {
4371                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4372                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4373            }
4374            DiffTransform::DeletedHunk {
4375                base_text_byte_range,
4376                buffer_id,
4377                has_trailing_newline,
4378                ..
4379            } => {
4380                let buffer_end = base_text_byte_range.start + overshoot;
4381                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4382                    panic!("{:?} is in non-existent deleted hunk", range.end)
4383                };
4384
4385                let mut suffix = base_text
4386                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4387                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4388                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4389                }
4390                suffix
4391            }
4392        };
4393
4394        result.add_assign(&suffix);
4395        result
4396    }
4397
4398    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4399    where
4400        D: TextDimension,
4401    {
4402        // let mut range = range.start..range.end;
4403        let mut summary = D::zero(&());
4404        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4405        cursor.seek(&range.start, Bias::Right, &());
4406        if let Some(excerpt) = cursor.item() {
4407            let mut end_before_newline = cursor.end(&());
4408            if excerpt.has_trailing_newline {
4409                end_before_newline -= ExcerptOffset::new(1);
4410            }
4411
4412            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4413            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4414            let end_in_excerpt =
4415                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4416            summary.add_assign(
4417                &excerpt
4418                    .buffer
4419                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4420            );
4421
4422            if range.end > end_before_newline {
4423                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4424            }
4425
4426            cursor.next(&());
4427        }
4428
4429        if range.end > *cursor.start() {
4430            summary.add_assign(
4431                &cursor
4432                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4433                    .0,
4434            );
4435            if let Some(excerpt) = cursor.item() {
4436                range.end = cmp::max(*cursor.start(), range.end);
4437
4438                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4439                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4440                summary.add_assign(
4441                    &excerpt
4442                        .buffer
4443                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4444                );
4445            }
4446        }
4447
4448        summary
4449    }
4450
4451    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4452    where
4453        D: TextDimension + Ord + Sub<D, Output = D>,
4454    {
4455        self.summaries_for_anchors([anchor])[0]
4456    }
4457
4458    fn resolve_summary_for_anchor<D>(
4459        &self,
4460        anchor: &Anchor,
4461        excerpt_position: D,
4462        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4463    ) -> D
4464    where
4465        D: TextDimension + Ord + Sub<D, Output = D>,
4466    {
4467        loop {
4468            let transform_end_position = diff_transforms.end(&()).0 .0;
4469            let at_transform_end =
4470                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4471            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4472                diff_transforms.next(&());
4473                continue;
4474            }
4475
4476            let mut position = diff_transforms.start().1 .0;
4477            match diff_transforms.item() {
4478                Some(DiffTransform::DeletedHunk {
4479                    buffer_id,
4480                    base_text_byte_range,
4481                    ..
4482                }) => {
4483                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4484                        if let Some(base_text) =
4485                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4486                        {
4487                            if base_text.can_resolve(&diff_base_anchor) {
4488                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4489                                if base_text_offset >= base_text_byte_range.start
4490                                    && base_text_offset <= base_text_byte_range.end
4491                                {
4492                                    let position_in_hunk = base_text
4493                                        .text_summary_for_range::<D, _>(
4494                                            base_text_byte_range.start..base_text_offset,
4495                                        );
4496                                    position.add_assign(&position_in_hunk);
4497                                } else if at_transform_end {
4498                                    diff_transforms.next(&());
4499                                    continue;
4500                                }
4501                            }
4502                        }
4503                    }
4504                }
4505                _ => {
4506                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4507                        diff_transforms.next(&());
4508                        continue;
4509                    }
4510                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4511                    position.add_assign(&overshoot);
4512                }
4513            }
4514
4515            return position;
4516        }
4517    }
4518
4519    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4520        let mut cursor = self
4521            .excerpts
4522            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4523        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4524
4525        cursor.seek(&Some(locator), Bias::Left, &());
4526        if cursor.item().is_none() {
4527            cursor.next(&());
4528        }
4529
4530        let mut position = cursor.start().1;
4531        if let Some(excerpt) = cursor.item() {
4532            if excerpt.id == anchor.excerpt_id {
4533                let excerpt_buffer_start = excerpt
4534                    .buffer
4535                    .offset_for_anchor(&excerpt.range.context.start);
4536                let excerpt_buffer_end =
4537                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4538                let buffer_position = cmp::min(
4539                    excerpt_buffer_end,
4540                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4541                );
4542                if buffer_position > excerpt_buffer_start {
4543                    position.value += buffer_position - excerpt_buffer_start;
4544                }
4545            }
4546        }
4547        position
4548    }
4549
4550    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4551    where
4552        D: TextDimension + Ord + Sub<D, Output = D>,
4553        I: 'a + IntoIterator<Item = &'a Anchor>,
4554    {
4555        let mut anchors = anchors.into_iter().peekable();
4556        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4557        let mut diff_transforms_cursor = self
4558            .diff_transforms
4559            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4560        diff_transforms_cursor.next(&());
4561
4562        let mut summaries = Vec::new();
4563        while let Some(anchor) = anchors.peek() {
4564            let excerpt_id = anchor.excerpt_id;
4565            let excerpt_anchors = iter::from_fn(|| {
4566                let anchor = anchors.peek()?;
4567                if anchor.excerpt_id == excerpt_id {
4568                    Some(anchors.next().unwrap())
4569                } else {
4570                    None
4571                }
4572            });
4573
4574            let locator = self.excerpt_locator_for_id(excerpt_id);
4575            cursor.seek_forward(locator, Bias::Left, &());
4576            if cursor.item().is_none() {
4577                cursor.next(&());
4578            }
4579
4580            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4581            if let Some(excerpt) = cursor.item() {
4582                if excerpt.id != excerpt_id {
4583                    let position = self.resolve_summary_for_anchor(
4584                        &Anchor::min(),
4585                        excerpt_start_position,
4586                        &mut diff_transforms_cursor,
4587                    );
4588                    summaries.extend(excerpt_anchors.map(|_| position));
4589                    continue;
4590                }
4591                let excerpt_buffer_start =
4592                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4593                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4594                for (buffer_summary, anchor) in excerpt
4595                    .buffer
4596                    .summaries_for_anchors_with_payload::<D, _, _>(
4597                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4598                    )
4599                {
4600                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4601                    let mut position = excerpt_start_position;
4602                    if summary > excerpt_buffer_start {
4603                        position.add_assign(&(summary - excerpt_buffer_start));
4604                    }
4605
4606                    if position > diff_transforms_cursor.start().0 .0 {
4607                        diff_transforms_cursor.seek_forward(
4608                            &ExcerptDimension(position),
4609                            Bias::Left,
4610                            &(),
4611                        );
4612                    }
4613
4614                    summaries.push(self.resolve_summary_for_anchor(
4615                        anchor,
4616                        position,
4617                        &mut diff_transforms_cursor,
4618                    ));
4619                }
4620            } else {
4621                diff_transforms_cursor.seek_forward(
4622                    &ExcerptDimension(excerpt_start_position),
4623                    Bias::Left,
4624                    &(),
4625                );
4626                let position = self.resolve_summary_for_anchor(
4627                    &Anchor::max(),
4628                    excerpt_start_position,
4629                    &mut diff_transforms_cursor,
4630                );
4631                summaries.extend(excerpt_anchors.map(|_| position));
4632            }
4633        }
4634
4635        summaries
4636    }
4637
4638    pub fn dimensions_from_points<'a, D>(
4639        &'a self,
4640        points: impl 'a + IntoIterator<Item = Point>,
4641    ) -> impl 'a + Iterator<Item = D>
4642    where
4643        D: TextDimension + Sub<D, Output = D>,
4644    {
4645        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4646        cursor.seek(&DimensionPair {
4647            key: Point::default(),
4648            value: None,
4649        });
4650        let mut points = points.into_iter();
4651        iter::from_fn(move || {
4652            let point = points.next()?;
4653
4654            cursor.seek_forward(&DimensionPair {
4655                key: point,
4656                value: None,
4657            });
4658
4659            if let Some(region) = cursor.region() {
4660                let overshoot = point - region.range.start.key;
4661                let buffer_point = region.buffer_range.start.key + overshoot;
4662                let mut position = region.range.start.value.unwrap();
4663                position.add_assign(
4664                    &region
4665                        .buffer
4666                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4667                );
4668                return Some(position);
4669            } else {
4670                return Some(D::from_text_summary(&self.text_summary()));
4671            }
4672        })
4673    }
4674
4675    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4676    where
4677        I: 'a + IntoIterator<Item = &'a Anchor>,
4678    {
4679        let mut anchors = anchors.into_iter().enumerate().peekable();
4680        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4681        cursor.next(&());
4682
4683        let mut result = Vec::new();
4684
4685        while let Some((_, anchor)) = anchors.peek() {
4686            let old_excerpt_id = anchor.excerpt_id;
4687
4688            // Find the location where this anchor's excerpt should be.
4689            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4690            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4691
4692            if cursor.item().is_none() {
4693                cursor.next(&());
4694            }
4695
4696            let next_excerpt = cursor.item();
4697            let prev_excerpt = cursor.prev_item();
4698
4699            // Process all of the anchors for this excerpt.
4700            while let Some((_, anchor)) = anchors.peek() {
4701                if anchor.excerpt_id != old_excerpt_id {
4702                    break;
4703                }
4704                let (anchor_ix, anchor) = anchors.next().unwrap();
4705                let mut anchor = *anchor;
4706
4707                // Leave min and max anchors unchanged if invalid or
4708                // if the old excerpt still exists at this location
4709                let mut kept_position = next_excerpt
4710                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4711                    || old_excerpt_id == ExcerptId::max()
4712                    || old_excerpt_id == ExcerptId::min();
4713
4714                // If the old excerpt no longer exists at this location, then attempt to
4715                // find an equivalent position for this anchor in an adjacent excerpt.
4716                if !kept_position {
4717                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4718                        if excerpt.contains(&anchor) {
4719                            anchor.excerpt_id = excerpt.id;
4720                            kept_position = true;
4721                            break;
4722                        }
4723                    }
4724                }
4725
4726                // If there's no adjacent excerpt that contains the anchor's position,
4727                // then report that the anchor has lost its position.
4728                if !kept_position {
4729                    anchor = if let Some(excerpt) = next_excerpt {
4730                        let mut text_anchor = excerpt
4731                            .range
4732                            .context
4733                            .start
4734                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4735                        if text_anchor
4736                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4737                            .is_gt()
4738                        {
4739                            text_anchor = excerpt.range.context.end;
4740                        }
4741                        Anchor {
4742                            buffer_id: Some(excerpt.buffer_id),
4743                            excerpt_id: excerpt.id,
4744                            text_anchor,
4745                            diff_base_anchor: None,
4746                        }
4747                    } else if let Some(excerpt) = prev_excerpt {
4748                        let mut text_anchor = excerpt
4749                            .range
4750                            .context
4751                            .end
4752                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4753                        if text_anchor
4754                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4755                            .is_lt()
4756                        {
4757                            text_anchor = excerpt.range.context.start;
4758                        }
4759                        Anchor {
4760                            buffer_id: Some(excerpt.buffer_id),
4761                            excerpt_id: excerpt.id,
4762                            text_anchor,
4763                            diff_base_anchor: None,
4764                        }
4765                    } else if anchor.text_anchor.bias == Bias::Left {
4766                        Anchor::min()
4767                    } else {
4768                        Anchor::max()
4769                    };
4770                }
4771
4772                result.push((anchor_ix, anchor, kept_position));
4773            }
4774        }
4775        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4776        result
4777    }
4778
4779    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4780        self.anchor_at(position, Bias::Left)
4781    }
4782
4783    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4784        self.anchor_at(position, Bias::Right)
4785    }
4786
4787    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4788        let offset = position.to_offset(self);
4789
4790        // Find the given position in the diff transforms. Determine the corresponding
4791        // offset in the excerpts, and whether the position is within a deleted hunk.
4792        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4793        diff_transforms.seek(&offset, Bias::Right, &());
4794
4795        if offset == diff_transforms.start().0 && bias == Bias::Left {
4796            if let Some(prev_item) = diff_transforms.prev_item() {
4797                match prev_item {
4798                    DiffTransform::DeletedHunk { .. } => {
4799                        diff_transforms.prev(&());
4800                    }
4801                    _ => {}
4802                }
4803            }
4804        }
4805        let offset_in_transform = offset - diff_transforms.start().0;
4806        let mut excerpt_offset = diff_transforms.start().1;
4807        let mut diff_base_anchor = None;
4808        if let Some(DiffTransform::DeletedHunk {
4809            buffer_id,
4810            base_text_byte_range,
4811            has_trailing_newline,
4812            ..
4813        }) = diff_transforms.item()
4814        {
4815            let diff = self.diffs.get(buffer_id).expect("missing diff");
4816            if offset_in_transform > base_text_byte_range.len() {
4817                debug_assert!(*has_trailing_newline);
4818                bias = Bias::Right;
4819            } else {
4820                diff_base_anchor = Some(
4821                    diff.base_text()
4822                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4823                );
4824                bias = Bias::Left;
4825            }
4826        } else {
4827            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4828        };
4829
4830        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4831            return Anchor {
4832                buffer_id: Some(buffer_id),
4833                excerpt_id: *excerpt_id,
4834                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4835                diff_base_anchor,
4836            };
4837        }
4838
4839        let mut excerpts = self
4840            .excerpts
4841            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4842        excerpts.seek(&excerpt_offset, Bias::Right, &());
4843        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4844            excerpts.prev(&());
4845        }
4846        if let Some(excerpt) = excerpts.item() {
4847            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4848            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4849                overshoot -= 1;
4850                bias = Bias::Right;
4851            }
4852
4853            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4854            let text_anchor =
4855                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4856            Anchor {
4857                buffer_id: Some(excerpt.buffer_id),
4858                excerpt_id: excerpt.id,
4859                text_anchor,
4860                diff_base_anchor,
4861            }
4862        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4863            Anchor::min()
4864        } else {
4865            Anchor::max()
4866        }
4867    }
4868
4869    /// Returns an anchor for the given excerpt and text anchor,
4870    /// returns None if the excerpt_id is no longer valid.
4871    pub fn anchor_in_excerpt(
4872        &self,
4873        excerpt_id: ExcerptId,
4874        text_anchor: text::Anchor,
4875    ) -> Option<Anchor> {
4876        let locator = self.excerpt_locator_for_id(excerpt_id);
4877        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4878        cursor.seek(locator, Bias::Left, &());
4879        if let Some(excerpt) = cursor.item() {
4880            if excerpt.id == excerpt_id {
4881                let text_anchor = excerpt.clip_anchor(text_anchor);
4882                drop(cursor);
4883                return Some(Anchor {
4884                    buffer_id: Some(excerpt.buffer_id),
4885                    excerpt_id,
4886                    text_anchor,
4887                    diff_base_anchor: None,
4888                });
4889            }
4890        }
4891        None
4892    }
4893
4894    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4895        Some(self.excerpt(excerpt_id)?.range.context.clone())
4896    }
4897
4898    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4899        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4900            true
4901        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4902            excerpt.buffer.can_resolve(&anchor.text_anchor)
4903        } else {
4904            false
4905        }
4906    }
4907
4908    pub fn excerpts(
4909        &self,
4910    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4911        self.excerpts
4912            .iter()
4913            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4914    }
4915
4916    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4917        let excerpts = self.excerpts.cursor(&());
4918        let diff_transforms = self.diff_transforms.cursor(&());
4919        MultiBufferCursor {
4920            excerpts,
4921            diff_transforms,
4922            diffs: &self.diffs,
4923            cached_region: None,
4924        }
4925    }
4926
4927    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4928        let start_locator = self.excerpt_locator_for_id(id);
4929        let mut excerpts = self
4930            .excerpts
4931            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4932        excerpts.seek(&Some(start_locator), Bias::Left, &());
4933        excerpts.prev(&());
4934
4935        let mut diff_transforms = self
4936            .diff_transforms
4937            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4938        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4939        if diff_transforms.end(&()).1 < excerpts.start().1 {
4940            diff_transforms.next(&());
4941        }
4942
4943        let excerpt = excerpts.item()?;
4944        Some(MultiBufferExcerpt {
4945            excerpt,
4946            offset: diff_transforms.start().0 .0,
4947            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4948            excerpt_offset: excerpts.start().1.clone(),
4949            diff_transforms,
4950        })
4951    }
4952
4953    pub fn excerpt_boundaries_in_range<R, T>(
4954        &self,
4955        range: R,
4956    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4957    where
4958        R: RangeBounds<T>,
4959        T: ToOffset,
4960    {
4961        let start_offset;
4962        let start = match range.start_bound() {
4963            Bound::Included(start) => {
4964                start_offset = start.to_offset(self);
4965                Bound::Included(start_offset)
4966            }
4967            Bound::Excluded(_) => {
4968                panic!("not supported")
4969            }
4970            Bound::Unbounded => {
4971                start_offset = 0;
4972                Bound::Unbounded
4973            }
4974        };
4975        let end = match range.end_bound() {
4976            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4977            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4978            Bound::Unbounded => Bound::Unbounded,
4979        };
4980        let bounds = (start, end);
4981
4982        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4983        cursor.seek(&DimensionPair {
4984            key: start_offset,
4985            value: None,
4986        });
4987
4988        if cursor
4989            .region()
4990            .is_some_and(|region| bounds.contains(&region.range.start.key))
4991        {
4992            cursor.prev_excerpt();
4993        } else {
4994            cursor.seek_to_start_of_current_excerpt();
4995        }
4996        let mut prev_region = cursor.region();
4997
4998        cursor.next_excerpt();
4999
5000        let mut visited_end = false;
5001        iter::from_fn(move || loop {
5002            if self.singleton {
5003                return None;
5004            }
5005
5006            let next_region = cursor.region();
5007            cursor.next_excerpt();
5008
5009            let next_region_start = if let Some(region) = &next_region {
5010                if !bounds.contains(&region.range.start.key) {
5011                    prev_region = next_region;
5012                    continue;
5013                }
5014                region.range.start.value.unwrap()
5015            } else {
5016                if !bounds.contains(&self.len()) {
5017                    return None;
5018                }
5019                self.max_point()
5020            };
5021            let next_region_end = if let Some(region) = cursor.region() {
5022                region.range.start.value.unwrap()
5023            } else {
5024                self.max_point()
5025            };
5026
5027            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5028                id: region.excerpt.id,
5029                buffer: region.excerpt.buffer.clone(),
5030                buffer_id: region.excerpt.buffer_id,
5031                range: region.excerpt.range.clone(),
5032                end_row: MultiBufferRow(next_region_start.row),
5033            });
5034
5035            let next = next_region.as_ref().map(|region| ExcerptInfo {
5036                id: region.excerpt.id,
5037                buffer: region.excerpt.buffer.clone(),
5038                buffer_id: region.excerpt.buffer_id,
5039                range: region.excerpt.range.clone(),
5040                end_row: if region.excerpt.has_trailing_newline {
5041                    MultiBufferRow(next_region_end.row - 1)
5042                } else {
5043                    MultiBufferRow(next_region_end.row)
5044                },
5045            });
5046
5047            if next.is_none() {
5048                if visited_end {
5049                    return None;
5050                } else {
5051                    visited_end = true;
5052                }
5053            }
5054
5055            let row = MultiBufferRow(next_region_start.row);
5056
5057            prev_region = next_region;
5058
5059            return Some(ExcerptBoundary { row, prev, next });
5060        })
5061    }
5062
5063    pub fn edit_count(&self) -> usize {
5064        self.edit_count
5065    }
5066
5067    pub fn non_text_state_update_count(&self) -> usize {
5068        self.non_text_state_update_count
5069    }
5070
5071    /// Returns the smallest enclosing bracket ranges containing the given range or
5072    /// None if no brackets contain range or the range is not contained in a single
5073    /// excerpt
5074    ///
5075    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5076    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5077        &self,
5078        range: Range<T>,
5079        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5080    ) -> Option<(Range<usize>, Range<usize>)> {
5081        let range = range.start.to_offset(self)..range.end.to_offset(self);
5082        let mut excerpt = self.excerpt_containing(range.clone())?;
5083        let buffer = excerpt.buffer();
5084        let excerpt_buffer_range = excerpt.buffer_range();
5085
5086        // Filter to ranges contained in the excerpt
5087        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5088            excerpt_buffer_range.contains(&open.start)
5089                && excerpt_buffer_range.contains(&close.end)
5090                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5091        };
5092
5093        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5094            excerpt.map_range_to_buffer(range),
5095            Some(&range_filter),
5096        )?;
5097
5098        Some((
5099            excerpt.map_range_from_buffer(open),
5100            excerpt.map_range_from_buffer(close),
5101        ))
5102    }
5103
5104    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5105    /// not contained in a single excerpt
5106    pub fn enclosing_bracket_ranges<T: ToOffset>(
5107        &self,
5108        range: Range<T>,
5109    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5110        let range = range.start.to_offset(self)..range.end.to_offset(self);
5111        let mut excerpt = self.excerpt_containing(range.clone())?;
5112
5113        Some(
5114            excerpt
5115                .buffer()
5116                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5117                .filter_map(move |pair| {
5118                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5119                        Some((
5120                            excerpt.map_range_from_buffer(pair.open_range),
5121                            excerpt.map_range_from_buffer(pair.close_range),
5122                        ))
5123                    } else {
5124                        None
5125                    }
5126                }),
5127        )
5128    }
5129
5130    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5131    /// not contained in a single excerpt
5132    pub fn text_object_ranges<T: ToOffset>(
5133        &self,
5134        range: Range<T>,
5135        options: TreeSitterOptions,
5136    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5137        let range = range.start.to_offset(self)..range.end.to_offset(self);
5138        self.excerpt_containing(range.clone())
5139            .map(|mut excerpt| {
5140                excerpt
5141                    .buffer()
5142                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5143                    .filter_map(move |(range, text_object)| {
5144                        if excerpt.contains_buffer_range(range.clone()) {
5145                            Some((excerpt.map_range_from_buffer(range), text_object))
5146                        } else {
5147                            None
5148                        }
5149                    })
5150            })
5151            .into_iter()
5152            .flatten()
5153    }
5154
5155    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5156    /// not contained in a single excerpt
5157    pub fn bracket_ranges<T: ToOffset>(
5158        &self,
5159        range: Range<T>,
5160    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5161        let range = range.start.to_offset(self)..range.end.to_offset(self);
5162        let mut excerpt = self.excerpt_containing(range.clone())?;
5163
5164        Some(
5165            excerpt
5166                .buffer()
5167                .bracket_ranges(excerpt.map_range_to_buffer(range))
5168                .filter_map(move |pair| {
5169                    let buffer_range = pair.open_range.start..pair.close_range.end;
5170                    if excerpt.contains_buffer_range(buffer_range) {
5171                        Some((
5172                            excerpt.map_range_from_buffer(pair.open_range),
5173                            excerpt.map_range_from_buffer(pair.close_range),
5174                        ))
5175                    } else {
5176                        None
5177                    }
5178                }),
5179        )
5180    }
5181
5182    pub fn redacted_ranges<'a, T: ToOffset>(
5183        &'a self,
5184        range: Range<T>,
5185        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5186    ) -> impl Iterator<Item = Range<usize>> + 'a {
5187        let range = range.start.to_offset(self)..range.end.to_offset(self);
5188        self.lift_buffer_metadata(range, move |buffer, range| {
5189            if redaction_enabled(buffer.file()) {
5190                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5191            } else {
5192                None
5193            }
5194        })
5195        .map(|(range, _, _)| range)
5196    }
5197
5198    pub fn runnable_ranges(
5199        &self,
5200        range: Range<Anchor>,
5201    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5202        let range = range.start.to_offset(self)..range.end.to_offset(self);
5203        self.lift_buffer_metadata(range, move |buffer, range| {
5204            Some(
5205                buffer
5206                    .runnable_ranges(range.clone())
5207                    .filter(move |runnable| {
5208                        runnable.run_range.start >= range.start
5209                            && runnable.run_range.end < range.end
5210                    })
5211                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5212            )
5213        })
5214        .map(|(run_range, runnable, _)| language::RunnableRange {
5215            run_range,
5216            ..runnable
5217        })
5218    }
5219
5220    pub fn line_indents(
5221        &self,
5222        start_row: MultiBufferRow,
5223        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5224    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5225        let max_point = self.max_point();
5226        let mut cursor = self.cursor::<Point>();
5227        cursor.seek(&Point::new(start_row.0, 0));
5228        iter::from_fn(move || {
5229            let mut region = cursor.region()?;
5230            while !buffer_filter(&region.excerpt.buffer) {
5231                cursor.next();
5232                region = cursor.region()?;
5233            }
5234            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5235            let buffer_start_row =
5236                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5237
5238            let buffer_end_row = if region.is_main_buffer
5239                && (region.has_trailing_newline || region.range.end == max_point)
5240            {
5241                region.buffer_range.end.row
5242            } else {
5243                region.buffer_range.end.row.saturating_sub(1)
5244            };
5245
5246            let line_indents = region
5247                .buffer
5248                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5249            cursor.next();
5250            return Some(line_indents.map(move |(buffer_row, indent)| {
5251                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5252                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5253            }));
5254        })
5255        .flatten()
5256    }
5257
5258    pub fn reversed_line_indents(
5259        &self,
5260        end_row: MultiBufferRow,
5261        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5262    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5263        let max_point = self.max_point();
5264        let mut cursor = self.cursor::<Point>();
5265        cursor.seek(&Point::new(end_row.0, 0));
5266        iter::from_fn(move || {
5267            let mut region = cursor.region()?;
5268            while !buffer_filter(&region.excerpt.buffer) {
5269                cursor.prev();
5270                region = cursor.region()?;
5271            }
5272
5273            let buffer_start_row = region.buffer_range.start.row;
5274            let buffer_end_row = if region.is_main_buffer
5275                && (region.has_trailing_newline || region.range.end == max_point)
5276            {
5277                region.buffer_range.end.row + 1
5278            } else {
5279                region.buffer_range.end.row
5280            };
5281
5282            let overshoot = end_row.0 - region.range.start.row;
5283            let buffer_end_row =
5284                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5285
5286            let line_indents = region
5287                .buffer
5288                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5289            cursor.prev();
5290            return Some(line_indents.map(move |(buffer_row, indent)| {
5291                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5292                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5293            }));
5294        })
5295        .flatten()
5296    }
5297
5298    pub async fn enclosing_indent(
5299        &self,
5300        mut target_row: MultiBufferRow,
5301    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5302        let max_row = MultiBufferRow(self.max_point().row);
5303        if target_row >= max_row {
5304            return None;
5305        }
5306
5307        let mut target_indent = self.line_indent_for_row(target_row);
5308
5309        // If the current row is at the start of an indented block, we want to return this
5310        // block as the enclosing indent.
5311        if !target_indent.is_line_empty() && target_row < max_row {
5312            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5313            if !next_line_indent.is_line_empty()
5314                && target_indent.raw_len() < next_line_indent.raw_len()
5315            {
5316                target_indent = next_line_indent;
5317                target_row.0 += 1;
5318            }
5319        }
5320
5321        const SEARCH_ROW_LIMIT: u32 = 25000;
5322        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5323        const YIELD_INTERVAL: u32 = 100;
5324
5325        let mut accessed_row_counter = 0;
5326
5327        // If there is a blank line at the current row, search for the next non indented lines
5328        if target_indent.is_line_empty() {
5329            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5330            let end =
5331                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5332
5333            let mut non_empty_line_above = None;
5334            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5335                if row < start {
5336                    break;
5337                }
5338                accessed_row_counter += 1;
5339                if accessed_row_counter == YIELD_INTERVAL {
5340                    accessed_row_counter = 0;
5341                    yield_now().await;
5342                }
5343                if !indent.is_line_empty() {
5344                    non_empty_line_above = Some((row, indent));
5345                    break;
5346                }
5347            }
5348
5349            let mut non_empty_line_below = None;
5350            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5351                if row > end {
5352                    break;
5353                }
5354                accessed_row_counter += 1;
5355                if accessed_row_counter == YIELD_INTERVAL {
5356                    accessed_row_counter = 0;
5357                    yield_now().await;
5358                }
5359                if !indent.is_line_empty() {
5360                    non_empty_line_below = Some((row, indent));
5361                    break;
5362                }
5363            }
5364
5365            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5366                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5367                    if above_indent.raw_len() >= below_indent.raw_len() {
5368                        (above_row, above_indent)
5369                    } else {
5370                        (below_row, below_indent)
5371                    }
5372                }
5373                (Some(above), None) => above,
5374                (None, Some(below)) => below,
5375                _ => return None,
5376            };
5377
5378            target_indent = indent;
5379            target_row = row;
5380        }
5381
5382        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5383        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5384
5385        let mut start_indent = None;
5386        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5387            if row < start {
5388                break;
5389            }
5390            accessed_row_counter += 1;
5391            if accessed_row_counter == YIELD_INTERVAL {
5392                accessed_row_counter = 0;
5393                yield_now().await;
5394            }
5395            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5396                start_indent = Some((row, indent));
5397                break;
5398            }
5399        }
5400        let (start_row, start_indent_size) = start_indent?;
5401
5402        let mut end_indent = (end, None);
5403        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5404            if row > end {
5405                break;
5406            }
5407            accessed_row_counter += 1;
5408            if accessed_row_counter == YIELD_INTERVAL {
5409                accessed_row_counter = 0;
5410                yield_now().await;
5411            }
5412            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5413                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5414                break;
5415            }
5416        }
5417        let (end_row, end_indent_size) = end_indent;
5418
5419        let indent = if let Some(end_indent_size) = end_indent_size {
5420            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5421                start_indent_size
5422            } else {
5423                end_indent_size
5424            }
5425        } else {
5426            start_indent_size
5427        };
5428
5429        Some((start_row..end_row, indent))
5430    }
5431
5432    pub fn indent_guides_in_range<T: ToPoint>(
5433        &self,
5434        range: Range<T>,
5435        ignore_disabled_for_language: bool,
5436        cx: &App,
5437    ) -> impl Iterator<Item = IndentGuide> {
5438        let range = range.start.to_point(self)..range.end.to_point(self);
5439        let start_row = MultiBufferRow(range.start.row);
5440        let end_row = MultiBufferRow(range.end.row);
5441
5442        let mut row_indents = self.line_indents(start_row, |buffer| {
5443            let settings =
5444                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5445            settings.indent_guides.enabled || ignore_disabled_for_language
5446        });
5447
5448        let mut result = Vec::new();
5449        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5450
5451        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5452            if first_row > end_row {
5453                break;
5454            }
5455            let current_depth = indent_stack.len() as u32;
5456
5457            let settings =
5458                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5459            let tab_size = settings.tab_size.get() as u32;
5460
5461            // When encountering empty, continue until found useful line indent
5462            // then add to the indent stack with the depth found
5463            let mut found_indent = false;
5464            let mut last_row = first_row;
5465            if line_indent.is_line_empty() {
5466                while !found_indent {
5467                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5468                        break;
5469                    };
5470                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5471                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5472                        break;
5473                    }
5474
5475                    if new_line_indent.is_line_empty() {
5476                        continue;
5477                    }
5478                    last_row = target_row.min(end_row);
5479                    line_indent = new_line_indent;
5480                    found_indent = true;
5481                    break;
5482                }
5483            } else {
5484                found_indent = true
5485            }
5486
5487            let depth = if found_indent {
5488                line_indent.len(tab_size) / tab_size
5489                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5490            } else {
5491                current_depth
5492            };
5493
5494            match depth.cmp(&current_depth) {
5495                cmp::Ordering::Less => {
5496                    for _ in 0..(current_depth - depth) {
5497                        let mut indent = indent_stack.pop().unwrap();
5498                        if last_row != first_row {
5499                            // In this case, we landed on an empty row, had to seek forward,
5500                            // and discovered that the indent we where on is ending.
5501                            // This means that the last display row must
5502                            // be on line that ends this indent range, so we
5503                            // should display the range up to the first non-empty line
5504                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5505                        }
5506
5507                        result.push(indent)
5508                    }
5509                }
5510                cmp::Ordering::Greater => {
5511                    for next_depth in current_depth..depth {
5512                        indent_stack.push(IndentGuide {
5513                            buffer_id: buffer.remote_id(),
5514                            start_row: first_row,
5515                            end_row: last_row,
5516                            depth: next_depth,
5517                            tab_size,
5518                            settings: settings.indent_guides,
5519                        });
5520                    }
5521                }
5522                _ => {}
5523            }
5524
5525            for indent in indent_stack.iter_mut() {
5526                indent.end_row = last_row;
5527            }
5528        }
5529
5530        result.extend(indent_stack);
5531        result.into_iter()
5532    }
5533
5534    pub fn trailing_excerpt_update_count(&self) -> usize {
5535        self.trailing_excerpt_update_count
5536    }
5537
5538    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5539        self.point_to_buffer_offset(point)
5540            .and_then(|(buffer, _)| buffer.file())
5541    }
5542
5543    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5544        self.point_to_buffer_offset(point)
5545            .and_then(|(buffer, offset)| buffer.language_at(offset))
5546    }
5547
5548    pub fn settings_at<'a, T: ToOffset>(
5549        &'a self,
5550        point: T,
5551        cx: &'a App,
5552    ) -> Cow<'a, LanguageSettings> {
5553        let mut language = None;
5554        let mut file = None;
5555        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5556            language = buffer.language_at(offset);
5557            file = buffer.file();
5558        }
5559        language_settings(language.map(|l| l.name()), file, cx)
5560    }
5561
5562    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5563        self.point_to_buffer_offset(point)
5564            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5565    }
5566
5567    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5568        self.point_to_buffer_offset(point)
5569            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5570            .unwrap_or_default()
5571    }
5572
5573    pub fn language_indent_size_at<T: ToOffset>(
5574        &self,
5575        position: T,
5576        cx: &App,
5577    ) -> Option<IndentSize> {
5578        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5579        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5580    }
5581
5582    pub fn is_dirty(&self) -> bool {
5583        self.is_dirty
5584    }
5585
5586    pub fn has_deleted_file(&self) -> bool {
5587        self.has_deleted_file
5588    }
5589
5590    pub fn has_conflict(&self) -> bool {
5591        self.has_conflict
5592    }
5593
5594    pub fn has_diagnostics(&self) -> bool {
5595        self.excerpts
5596            .iter()
5597            .any(|excerpt| excerpt.buffer.has_diagnostics())
5598    }
5599
5600    pub fn diagnostic_group(
5601        &self,
5602        buffer_id: BufferId,
5603        group_id: usize,
5604    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5605        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5606            if buffer.remote_id() != buffer_id {
5607                return None;
5608            };
5609            Some(
5610                buffer
5611                    .diagnostic_group(group_id)
5612                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5613            )
5614        })
5615        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5616    }
5617
5618    pub fn diagnostics_in_range<'a, T>(
5619        &'a self,
5620        range: Range<T>,
5621    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5622    where
5623        T: 'a
5624            + text::ToOffset
5625            + text::FromAnchor
5626            + TextDimension
5627            + Ord
5628            + Sub<T, Output = T>
5629            + fmt::Debug,
5630    {
5631        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5632            Some(
5633                buffer
5634                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5635                    .map(|entry| (entry.range, entry.diagnostic)),
5636            )
5637        })
5638        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5639    }
5640
5641    pub fn syntax_ancestor<T: ToOffset>(
5642        &self,
5643        range: Range<T>,
5644    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5645        let range = range.start.to_offset(self)..range.end.to_offset(self);
5646        let mut excerpt = self.excerpt_containing(range.clone())?;
5647        let node = excerpt
5648            .buffer()
5649            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5650        let node_range = node.byte_range();
5651        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5652            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5653        } else {
5654            MultiOrSingleBufferOffsetRange::Single(node_range)
5655        };
5656        Some((node, range))
5657    }
5658
5659    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5660        let (excerpt_id, _, buffer) = self.as_singleton()?;
5661        let outline = buffer.outline(theme)?;
5662        Some(Outline::new(
5663            outline
5664                .items
5665                .into_iter()
5666                .flat_map(|item| {
5667                    Some(OutlineItem {
5668                        depth: item.depth,
5669                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5670                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5671                        text: item.text,
5672                        highlight_ranges: item.highlight_ranges,
5673                        name_ranges: item.name_ranges,
5674                        body_range: item.body_range.and_then(|body_range| {
5675                            Some(
5676                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5677                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5678                            )
5679                        }),
5680                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5681                            Some(
5682                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5683                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5684                            )
5685                        }),
5686                    })
5687                })
5688                .collect(),
5689        ))
5690    }
5691
5692    pub fn symbols_containing<T: ToOffset>(
5693        &self,
5694        offset: T,
5695        theme: Option<&SyntaxTheme>,
5696    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5697        let anchor = self.anchor_before(offset);
5698        let excerpt_id = anchor.excerpt_id;
5699        let excerpt = self.excerpt(excerpt_id)?;
5700        Some((
5701            excerpt.buffer_id,
5702            excerpt
5703                .buffer
5704                .symbols_containing(anchor.text_anchor, theme)
5705                .into_iter()
5706                .flatten()
5707                .flat_map(|item| {
5708                    Some(OutlineItem {
5709                        depth: item.depth,
5710                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5711                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5712                        text: item.text,
5713                        highlight_ranges: item.highlight_ranges,
5714                        name_ranges: item.name_ranges,
5715                        body_range: item.body_range.and_then(|body_range| {
5716                            Some(
5717                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5718                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5719                            )
5720                        }),
5721                        annotation_range: item.annotation_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                    })
5728                })
5729                .collect(),
5730        ))
5731    }
5732
5733    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5734        if id == ExcerptId::min() {
5735            Locator::min_ref()
5736        } else if id == ExcerptId::max() {
5737            Locator::max_ref()
5738        } else {
5739            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5740            cursor.seek(&id, Bias::Left, &());
5741            if let Some(entry) = cursor.item() {
5742                if entry.id == id {
5743                    return &entry.locator;
5744                }
5745            }
5746            panic!("invalid excerpt id {:?}", id)
5747        }
5748    }
5749
5750    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5751    fn excerpt_locators_for_ids(
5752        &self,
5753        ids: impl IntoIterator<Item = ExcerptId>,
5754    ) -> SmallVec<[Locator; 1]> {
5755        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5756        sorted_ids.sort_unstable();
5757        let mut locators = SmallVec::new();
5758
5759        while sorted_ids.last() == Some(&ExcerptId::max()) {
5760            sorted_ids.pop();
5761            if let Some(mapping) = self.excerpt_ids.last() {
5762                locators.push(mapping.locator.clone());
5763            }
5764        }
5765
5766        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5767        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5768            sorted_ids.next();
5769            if let Some(mapping) = self.excerpt_ids.first() {
5770                locators.push(mapping.locator.clone());
5771            }
5772        }
5773
5774        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5775        for id in sorted_ids {
5776            if cursor.seek_forward(&id, Bias::Left, &()) {
5777                locators.push(cursor.item().unwrap().locator.clone());
5778            } else {
5779                panic!("invalid excerpt id {:?}", id);
5780            }
5781        }
5782
5783        locators.sort_unstable();
5784        locators
5785    }
5786
5787    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5788        Some(self.excerpt(excerpt_id)?.buffer_id)
5789    }
5790
5791    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5792        Some(&self.excerpt(excerpt_id)?.buffer)
5793    }
5794
5795    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5796        let mut cursor = self
5797            .excerpts
5798            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5799        let locator = self.excerpt_locator_for_id(excerpt_id);
5800        if cursor.seek(&Some(locator), Bias::Left, &()) {
5801            let start = cursor.start().1.clone();
5802            let end = cursor.end(&()).1;
5803            let mut diff_transforms = self
5804                .diff_transforms
5805                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5806            diff_transforms.seek(&start, Bias::Left, &());
5807            let overshoot = start.0 - diff_transforms.start().0 .0;
5808            let start = diff_transforms.start().1 .0 + overshoot;
5809            diff_transforms.seek(&end, Bias::Right, &());
5810            let overshoot = end.0 - diff_transforms.start().0 .0;
5811            let end = diff_transforms.start().1 .0 + overshoot;
5812            Some(start..end)
5813        } else {
5814            None
5815        }
5816    }
5817
5818    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5819        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5820        let locator = self.excerpt_locator_for_id(excerpt_id);
5821        if cursor.seek(&Some(locator), Bias::Left, &()) {
5822            if let Some(excerpt) = cursor.item() {
5823                return Some(excerpt.range.context.clone());
5824            }
5825        }
5826        None
5827    }
5828
5829    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5830        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5831        let locator = self.excerpt_locator_for_id(excerpt_id);
5832        cursor.seek(&Some(locator), Bias::Left, &());
5833        if let Some(excerpt) = cursor.item() {
5834            if excerpt.id == excerpt_id {
5835                return Some(excerpt);
5836            }
5837        }
5838        None
5839    }
5840
5841    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5842    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5843        let range = range.start.to_offset(self)..range.end.to_offset(self);
5844        let mut cursor = self.cursor::<usize>();
5845        cursor.seek(&range.start);
5846
5847        let start_excerpt = cursor.excerpt()?;
5848        if range.end != range.start {
5849            cursor.seek_forward(&range.end);
5850            if cursor.excerpt()?.id != start_excerpt.id {
5851                return None;
5852            }
5853        }
5854
5855        cursor.seek_to_start_of_current_excerpt();
5856        let region = cursor.region()?;
5857        let offset = region.range.start;
5858        let buffer_offset = region.buffer_range.start;
5859        let excerpt_offset = cursor.excerpts.start().clone();
5860        Some(MultiBufferExcerpt {
5861            diff_transforms: cursor.diff_transforms,
5862            excerpt: start_excerpt,
5863            offset,
5864            buffer_offset,
5865            excerpt_offset,
5866        })
5867    }
5868
5869    pub fn selections_in_range<'a>(
5870        &'a self,
5871        range: &'a Range<Anchor>,
5872        include_local: bool,
5873    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5874        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5875        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5876        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5877        cursor.seek(start_locator, Bias::Left, &());
5878        cursor
5879            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5880            .flat_map(move |excerpt| {
5881                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5882                if excerpt.id == range.start.excerpt_id {
5883                    query_range.start = range.start.text_anchor;
5884                }
5885                if excerpt.id == range.end.excerpt_id {
5886                    query_range.end = range.end.text_anchor;
5887                }
5888
5889                excerpt
5890                    .buffer
5891                    .selections_in_range(query_range, include_local)
5892                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5893                        selections.map(move |selection| {
5894                            let mut start = Anchor {
5895                                buffer_id: Some(excerpt.buffer_id),
5896                                excerpt_id: excerpt.id,
5897                                text_anchor: selection.start,
5898                                diff_base_anchor: None,
5899                            };
5900                            let mut end = Anchor {
5901                                buffer_id: Some(excerpt.buffer_id),
5902                                excerpt_id: excerpt.id,
5903                                text_anchor: selection.end,
5904                                diff_base_anchor: None,
5905                            };
5906                            if range.start.cmp(&start, self).is_gt() {
5907                                start = range.start;
5908                            }
5909                            if range.end.cmp(&end, self).is_lt() {
5910                                end = range.end;
5911                            }
5912
5913                            (
5914                                replica_id,
5915                                line_mode,
5916                                cursor_shape,
5917                                Selection {
5918                                    id: selection.id,
5919                                    start,
5920                                    end,
5921                                    reversed: selection.reversed,
5922                                    goal: selection.goal,
5923                                },
5924                            )
5925                        })
5926                    })
5927            })
5928    }
5929
5930    pub fn show_headers(&self) -> bool {
5931        self.show_headers
5932    }
5933
5934    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5935        self.diffs.get(&buffer_id)
5936    }
5937}
5938
5939#[cfg(any(test, feature = "test-support"))]
5940impl MultiBufferSnapshot {
5941    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5942        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5943        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5944        start..end
5945    }
5946
5947    #[cfg(any(test, feature = "test-support"))]
5948    fn check_invariants(&self) {
5949        let excerpts = self.excerpts.items(&());
5950        let excerpt_ids = self.excerpt_ids.items(&());
5951
5952        for (ix, excerpt) in excerpts.iter().enumerate() {
5953            if ix == 0 {
5954                if excerpt.locator <= Locator::min() {
5955                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5956                }
5957            } else if excerpt.locator <= excerpts[ix - 1].locator {
5958                panic!("excerpts are out-of-order: {:?}", excerpts);
5959            }
5960        }
5961
5962        for (ix, entry) in excerpt_ids.iter().enumerate() {
5963            if ix == 0 {
5964                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5965                    panic!("invalid first excerpt id {:?}", entry.id);
5966                }
5967            } else if entry.id <= excerpt_ids[ix - 1].id {
5968                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5969            }
5970        }
5971
5972        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5973            panic!(
5974                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5975                self.excerpts.summary().text.len,
5976                self.diff_transforms.summary().input,
5977                self.diff_transforms.items(&()),
5978            );
5979        }
5980
5981        let mut prev_transform: Option<&DiffTransform> = None;
5982        for item in self.diff_transforms.iter() {
5983            if let DiffTransform::BufferContent {
5984                summary,
5985                inserted_hunk_info,
5986            } = item
5987            {
5988                if let Some(DiffTransform::BufferContent {
5989                    inserted_hunk_info: prev_inserted_hunk_info,
5990                    ..
5991                }) = prev_transform
5992                {
5993                    if *inserted_hunk_info == *prev_inserted_hunk_info {
5994                        panic!(
5995                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
5996                            self.diff_transforms.items(&()));
5997                    }
5998                }
5999                if summary.len == 0 && !self.is_empty() {
6000                    panic!("empty buffer content transform");
6001                }
6002            }
6003            prev_transform = Some(item);
6004        }
6005    }
6006}
6007
6008impl<'a, D> MultiBufferCursor<'a, D>
6009where
6010    D: TextDimension + Ord + Sub<D, Output = D>,
6011{
6012    fn seek(&mut self, position: &D) {
6013        self.cached_region.take();
6014        self.diff_transforms
6015            .seek(&OutputDimension(*position), Bias::Right, &());
6016        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6017            self.diff_transforms.prev(&());
6018        }
6019
6020        let mut excerpt_position = self.diff_transforms.start().1 .0;
6021        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6022            let overshoot = *position - self.diff_transforms.start().0 .0;
6023            excerpt_position.add_assign(&overshoot);
6024        }
6025
6026        self.excerpts
6027            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6028        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6029            self.excerpts.prev(&());
6030        }
6031    }
6032
6033    fn seek_forward(&mut self, position: &D) {
6034        self.cached_region.take();
6035        self.diff_transforms
6036            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6037        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6038            self.diff_transforms.prev(&());
6039        }
6040
6041        let overshoot = *position - self.diff_transforms.start().0 .0;
6042        let mut excerpt_position = self.diff_transforms.start().1 .0;
6043        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6044            excerpt_position.add_assign(&overshoot);
6045        }
6046
6047        self.excerpts
6048            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6049        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6050            self.excerpts.prev(&());
6051        }
6052    }
6053
6054    fn next_excerpt(&mut self) {
6055        self.excerpts.next(&());
6056        self.seek_to_start_of_current_excerpt();
6057    }
6058
6059    fn prev_excerpt(&mut self) {
6060        self.excerpts.prev(&());
6061        self.seek_to_start_of_current_excerpt();
6062    }
6063
6064    fn seek_to_start_of_current_excerpt(&mut self) {
6065        self.cached_region.take();
6066        self.diff_transforms
6067            .seek(self.excerpts.start(), Bias::Left, &());
6068        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6069            && self.diff_transforms.start().1 < *self.excerpts.start()
6070            && self.diff_transforms.next_item().is_some()
6071        {
6072            self.diff_transforms.next(&());
6073        }
6074    }
6075
6076    fn next(&mut self) {
6077        self.cached_region.take();
6078        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6079            cmp::Ordering::Less => self.diff_transforms.next(&()),
6080            cmp::Ordering::Greater => self.excerpts.next(&()),
6081            cmp::Ordering::Equal => {
6082                self.diff_transforms.next(&());
6083                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6084                    || self.diff_transforms.item().is_none()
6085                {
6086                    self.excerpts.next(&());
6087                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6088                    self.diff_transforms.item()
6089                {
6090                    if self
6091                        .excerpts
6092                        .item()
6093                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6094                    {
6095                        self.excerpts.next(&());
6096                    }
6097                }
6098            }
6099        }
6100    }
6101
6102    fn prev(&mut self) {
6103        self.cached_region.take();
6104        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6105            cmp::Ordering::Less => self.excerpts.prev(&()),
6106            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6107            cmp::Ordering::Equal => {
6108                self.diff_transforms.prev(&());
6109                if self.diff_transforms.start().1 < *self.excerpts.start()
6110                    || self.diff_transforms.item().is_none()
6111                {
6112                    self.excerpts.prev(&());
6113                }
6114            }
6115        }
6116    }
6117
6118    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6119        if self.cached_region.is_none() {
6120            self.cached_region = self.build_region();
6121        }
6122        self.cached_region.clone()
6123    }
6124
6125    fn is_at_end_of_excerpt(&mut self) -> bool {
6126        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6127            return false;
6128        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6129            || self.diff_transforms.item().is_none()
6130        {
6131            return true;
6132        }
6133
6134        let next_transform = self.diff_transforms.next_item();
6135        next_transform.map_or(true, |next_transform| match next_transform {
6136            DiffTransform::BufferContent { .. } => true,
6137            DiffTransform::DeletedHunk { hunk_info, .. } => self
6138                .excerpts
6139                .item()
6140                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6141        })
6142    }
6143
6144    fn main_buffer_position(&self) -> Option<D> {
6145        let excerpt = self.excerpts.item()?;
6146        let buffer = &excerpt.buffer;
6147        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6148        let mut buffer_start = buffer_context_start;
6149        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6150        buffer_start.add_assign(&overshoot);
6151        Some(buffer_start)
6152    }
6153
6154    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6155        let excerpt = self.excerpts.item()?;
6156        match self.diff_transforms.item()? {
6157            DiffTransform::DeletedHunk {
6158                buffer_id,
6159                base_text_byte_range,
6160                has_trailing_newline,
6161                hunk_info,
6162                ..
6163            } => {
6164                let diff = self.diffs.get(&buffer_id)?;
6165                let buffer = diff.base_text();
6166                let mut rope_cursor = buffer.as_rope().cursor(0);
6167                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6168                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6169                let mut buffer_end = buffer_start;
6170                buffer_end.add_assign(&buffer_range_len);
6171                let start = self.diff_transforms.start().0 .0;
6172                let end = self.diff_transforms.end(&()).0 .0;
6173                return Some(MultiBufferRegion {
6174                    buffer,
6175                    excerpt,
6176                    has_trailing_newline: *has_trailing_newline,
6177                    is_main_buffer: false,
6178                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6179                        hunk_info.hunk_secondary_status,
6180                    )),
6181                    buffer_range: buffer_start..buffer_end,
6182                    range: start..end,
6183                });
6184            }
6185            DiffTransform::BufferContent {
6186                inserted_hunk_info, ..
6187            } => {
6188                let buffer = &excerpt.buffer;
6189                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6190
6191                let mut start = self.diff_transforms.start().0 .0;
6192                let mut buffer_start = buffer_context_start;
6193                if self.diff_transforms.start().1 < *self.excerpts.start() {
6194                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6195                    start.add_assign(&overshoot);
6196                } else {
6197                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6198                    buffer_start.add_assign(&overshoot);
6199                }
6200
6201                let mut end;
6202                let mut buffer_end;
6203                let has_trailing_newline;
6204                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6205                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6206                    end = self.diff_transforms.end(&()).0 .0;
6207                    buffer_end = buffer_context_start;
6208                    buffer_end.add_assign(&overshoot);
6209                    has_trailing_newline = false;
6210                } else {
6211                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6212                    end = self.diff_transforms.start().0 .0;
6213                    end.add_assign(&overshoot);
6214                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6215                    has_trailing_newline = excerpt.has_trailing_newline;
6216                };
6217
6218                Some(MultiBufferRegion {
6219                    buffer,
6220                    excerpt,
6221                    has_trailing_newline,
6222                    is_main_buffer: true,
6223                    diff_hunk_status: inserted_hunk_info
6224                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6225                    buffer_range: buffer_start..buffer_end,
6226                    range: start..end,
6227                })
6228            }
6229        }
6230    }
6231
6232    fn excerpt(&self) -> Option<&'a Excerpt> {
6233        self.excerpts.item()
6234    }
6235}
6236
6237impl History {
6238    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6239        self.transaction_depth += 1;
6240        if self.transaction_depth == 1 {
6241            let id = self.next_transaction_id.tick();
6242            self.undo_stack.push(Transaction {
6243                id,
6244                buffer_transactions: Default::default(),
6245                first_edit_at: now,
6246                last_edit_at: now,
6247                suppress_grouping: false,
6248            });
6249            Some(id)
6250        } else {
6251            None
6252        }
6253    }
6254
6255    fn end_transaction(
6256        &mut self,
6257        now: Instant,
6258        buffer_transactions: HashMap<BufferId, TransactionId>,
6259    ) -> bool {
6260        assert_ne!(self.transaction_depth, 0);
6261        self.transaction_depth -= 1;
6262        if self.transaction_depth == 0 {
6263            if buffer_transactions.is_empty() {
6264                self.undo_stack.pop();
6265                false
6266            } else {
6267                self.redo_stack.clear();
6268                let transaction = self.undo_stack.last_mut().unwrap();
6269                transaction.last_edit_at = now;
6270                for (buffer_id, transaction_id) in buffer_transactions {
6271                    transaction
6272                        .buffer_transactions
6273                        .entry(buffer_id)
6274                        .or_insert(transaction_id);
6275                }
6276                true
6277            }
6278        } else {
6279            false
6280        }
6281    }
6282
6283    fn push_transaction<'a, T>(
6284        &mut self,
6285        buffer_transactions: T,
6286        now: Instant,
6287        cx: &Context<MultiBuffer>,
6288    ) where
6289        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6290    {
6291        assert_eq!(self.transaction_depth, 0);
6292        let transaction = Transaction {
6293            id: self.next_transaction_id.tick(),
6294            buffer_transactions: buffer_transactions
6295                .into_iter()
6296                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6297                .collect(),
6298            first_edit_at: now,
6299            last_edit_at: now,
6300            suppress_grouping: false,
6301        };
6302        if !transaction.buffer_transactions.is_empty() {
6303            self.undo_stack.push(transaction);
6304            self.redo_stack.clear();
6305        }
6306    }
6307
6308    fn finalize_last_transaction(&mut self) {
6309        if let Some(transaction) = self.undo_stack.last_mut() {
6310            transaction.suppress_grouping = true;
6311        }
6312    }
6313
6314    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6315        if let Some(ix) = self
6316            .undo_stack
6317            .iter()
6318            .rposition(|transaction| transaction.id == transaction_id)
6319        {
6320            Some(self.undo_stack.remove(ix))
6321        } else if let Some(ix) = self
6322            .redo_stack
6323            .iter()
6324            .rposition(|transaction| transaction.id == transaction_id)
6325        {
6326            Some(self.redo_stack.remove(ix))
6327        } else {
6328            None
6329        }
6330    }
6331
6332    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6333        self.undo_stack
6334            .iter()
6335            .find(|transaction| transaction.id == transaction_id)
6336            .or_else(|| {
6337                self.redo_stack
6338                    .iter()
6339                    .find(|transaction| transaction.id == transaction_id)
6340            })
6341    }
6342
6343    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6344        self.undo_stack
6345            .iter_mut()
6346            .find(|transaction| transaction.id == transaction_id)
6347            .or_else(|| {
6348                self.redo_stack
6349                    .iter_mut()
6350                    .find(|transaction| transaction.id == transaction_id)
6351            })
6352    }
6353
6354    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6355        assert_eq!(self.transaction_depth, 0);
6356        if let Some(transaction) = self.undo_stack.pop() {
6357            self.redo_stack.push(transaction);
6358            self.redo_stack.last_mut()
6359        } else {
6360            None
6361        }
6362    }
6363
6364    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6365        assert_eq!(self.transaction_depth, 0);
6366        if let Some(transaction) = self.redo_stack.pop() {
6367            self.undo_stack.push(transaction);
6368            self.undo_stack.last_mut()
6369        } else {
6370            None
6371        }
6372    }
6373
6374    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6375        let ix = self
6376            .undo_stack
6377            .iter()
6378            .rposition(|transaction| transaction.id == transaction_id)?;
6379        let transaction = self.undo_stack.remove(ix);
6380        self.redo_stack.push(transaction);
6381        self.redo_stack.last()
6382    }
6383
6384    fn group(&mut self) -> Option<TransactionId> {
6385        let mut count = 0;
6386        let mut transactions = self.undo_stack.iter();
6387        if let Some(mut transaction) = transactions.next_back() {
6388            while let Some(prev_transaction) = transactions.next_back() {
6389                if !prev_transaction.suppress_grouping
6390                    && transaction.first_edit_at - prev_transaction.last_edit_at
6391                        <= self.group_interval
6392                {
6393                    transaction = prev_transaction;
6394                    count += 1;
6395                } else {
6396                    break;
6397                }
6398            }
6399        }
6400        self.group_trailing(count)
6401    }
6402
6403    fn group_until(&mut self, transaction_id: TransactionId) {
6404        let mut count = 0;
6405        for transaction in self.undo_stack.iter().rev() {
6406            if transaction.id == transaction_id {
6407                self.group_trailing(count);
6408                break;
6409            } else if transaction.suppress_grouping {
6410                break;
6411            } else {
6412                count += 1;
6413            }
6414        }
6415    }
6416
6417    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6418        let new_len = self.undo_stack.len() - n;
6419        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6420        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6421            if let Some(transaction) = transactions_to_merge.last() {
6422                last_transaction.last_edit_at = transaction.last_edit_at;
6423            }
6424            for to_merge in transactions_to_merge {
6425                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6426                    last_transaction
6427                        .buffer_transactions
6428                        .entry(*buffer_id)
6429                        .or_insert(*transaction_id);
6430                }
6431            }
6432        }
6433
6434        self.undo_stack.truncate(new_len);
6435        self.undo_stack.last().map(|t| t.id)
6436    }
6437}
6438
6439impl Excerpt {
6440    fn new(
6441        id: ExcerptId,
6442        locator: Locator,
6443        buffer_id: BufferId,
6444        buffer: BufferSnapshot,
6445        range: ExcerptRange<text::Anchor>,
6446        has_trailing_newline: bool,
6447    ) -> Self {
6448        Excerpt {
6449            id,
6450            locator,
6451            max_buffer_row: range.context.end.to_point(&buffer).row,
6452            text_summary: buffer
6453                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6454            buffer_id,
6455            buffer,
6456            range,
6457            has_trailing_newline,
6458        }
6459    }
6460
6461    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6462        let content_start = self.range.context.start.to_offset(&self.buffer);
6463        let chunks_start = content_start + range.start;
6464        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6465
6466        let footer_height = if self.has_trailing_newline
6467            && range.start <= self.text_summary.len
6468            && range.end > self.text_summary.len
6469        {
6470            1
6471        } else {
6472            0
6473        };
6474
6475        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6476
6477        ExcerptChunks {
6478            excerpt_id: self.id,
6479            content_chunks,
6480            footer_height,
6481        }
6482    }
6483
6484    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6485        let content_start = self.range.context.start.to_offset(&self.buffer);
6486        let chunks_start = content_start + range.start;
6487        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6488        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6489        excerpt_chunks.footer_height = if self.has_trailing_newline
6490            && range.start <= self.text_summary.len
6491            && range.end > self.text_summary.len
6492        {
6493            1
6494        } else {
6495            0
6496        };
6497    }
6498
6499    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6500        if text_anchor
6501            .cmp(&self.range.context.start, &self.buffer)
6502            .is_lt()
6503        {
6504            self.range.context.start
6505        } else if text_anchor
6506            .cmp(&self.range.context.end, &self.buffer)
6507            .is_gt()
6508        {
6509            self.range.context.end
6510        } else {
6511            text_anchor
6512        }
6513    }
6514
6515    fn contains(&self, anchor: &Anchor) -> bool {
6516        Some(self.buffer_id) == anchor.buffer_id
6517            && self
6518                .range
6519                .context
6520                .start
6521                .cmp(&anchor.text_anchor, &self.buffer)
6522                .is_le()
6523            && self
6524                .range
6525                .context
6526                .end
6527                .cmp(&anchor.text_anchor, &self.buffer)
6528                .is_ge()
6529    }
6530
6531    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6532    fn buffer_start_offset(&self) -> usize {
6533        self.range.context.start.to_offset(&self.buffer)
6534    }
6535
6536    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6537    fn buffer_end_offset(&self) -> usize {
6538        self.buffer_start_offset() + self.text_summary.len
6539    }
6540}
6541
6542impl<'a> MultiBufferExcerpt<'a> {
6543    pub fn id(&self) -> ExcerptId {
6544        self.excerpt.id
6545    }
6546
6547    pub fn buffer_id(&self) -> BufferId {
6548        self.excerpt.buffer_id
6549    }
6550
6551    pub fn start_anchor(&self) -> Anchor {
6552        Anchor {
6553            buffer_id: Some(self.excerpt.buffer_id),
6554            excerpt_id: self.excerpt.id,
6555            text_anchor: self.excerpt.range.context.start,
6556            diff_base_anchor: None,
6557        }
6558    }
6559
6560    pub fn end_anchor(&self) -> Anchor {
6561        Anchor {
6562            buffer_id: Some(self.excerpt.buffer_id),
6563            excerpt_id: self.excerpt.id,
6564            text_anchor: self.excerpt.range.context.end,
6565            diff_base_anchor: None,
6566        }
6567    }
6568
6569    pub fn buffer(&self) -> &'a BufferSnapshot {
6570        &self.excerpt.buffer
6571    }
6572
6573    pub fn buffer_range(&self) -> Range<usize> {
6574        self.buffer_offset
6575            ..self
6576                .excerpt
6577                .range
6578                .context
6579                .end
6580                .to_offset(&self.excerpt.buffer.text)
6581    }
6582
6583    pub fn start_offset(&self) -> usize {
6584        self.offset
6585    }
6586
6587    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6588    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6589        self.map_range_to_buffer(offset..offset).start
6590    }
6591
6592    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6593    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6594        self.diff_transforms
6595            .seek(&OutputDimension(range.start), Bias::Right, &());
6596        let start = self.map_offset_to_buffer_internal(range.start);
6597        let end = if range.end > range.start {
6598            self.diff_transforms
6599                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6600            self.map_offset_to_buffer_internal(range.end)
6601        } else {
6602            start
6603        };
6604        start..end
6605    }
6606
6607    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6608        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6609        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6610            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6611        };
6612        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6613        self.buffer_offset + offset_in_excerpt
6614    }
6615
6616    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6617    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6618        self.map_range_from_buffer(buffer_offset..buffer_offset)
6619            .start
6620    }
6621
6622    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6623    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6624        if buffer_range.start < self.buffer_offset {
6625            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6626            return buffer_range;
6627        }
6628        let overshoot = buffer_range.start - self.buffer_offset;
6629        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6630        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6631        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6632            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6633            return buffer_range;
6634        }
6635        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6636        let start = self.diff_transforms.start().0 .0 + overshoot;
6637
6638        let end = if buffer_range.end > buffer_range.start {
6639            let overshoot = buffer_range.end - self.buffer_offset;
6640            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6641            self.diff_transforms
6642                .seek_forward(&excerpt_offset, Bias::Right, &());
6643            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6644            self.diff_transforms.start().0 .0 + overshoot
6645        } else {
6646            start
6647        };
6648
6649        start..end
6650    }
6651
6652    /// Returns true if the entirety of the given range is in the buffer's excerpt
6653    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6654        range.start >= self.excerpt.buffer_start_offset()
6655            && range.end <= self.excerpt.buffer_end_offset()
6656    }
6657
6658    pub fn max_buffer_row(&self) -> u32 {
6659        self.excerpt.max_buffer_row
6660    }
6661}
6662
6663impl ExcerptId {
6664    pub fn min() -> Self {
6665        Self(0)
6666    }
6667
6668    pub fn max() -> Self {
6669        Self(usize::MAX)
6670    }
6671
6672    pub fn to_proto(&self) -> u64 {
6673        self.0 as _
6674    }
6675
6676    pub fn from_proto(proto: u64) -> Self {
6677        Self(proto as _)
6678    }
6679
6680    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6681        let a = snapshot.excerpt_locator_for_id(*self);
6682        let b = snapshot.excerpt_locator_for_id(*other);
6683        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6684    }
6685}
6686
6687impl From<ExcerptId> for usize {
6688    fn from(val: ExcerptId) -> Self {
6689        val.0
6690    }
6691}
6692
6693impl fmt::Debug for Excerpt {
6694    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6695        f.debug_struct("Excerpt")
6696            .field("id", &self.id)
6697            .field("locator", &self.locator)
6698            .field("buffer_id", &self.buffer_id)
6699            .field("range", &self.range)
6700            .field("text_summary", &self.text_summary)
6701            .field("has_trailing_newline", &self.has_trailing_newline)
6702            .finish()
6703    }
6704}
6705
6706impl sum_tree::Item for Excerpt {
6707    type Summary = ExcerptSummary;
6708
6709    fn summary(&self, _cx: &()) -> Self::Summary {
6710        let mut text = self.text_summary;
6711        if self.has_trailing_newline {
6712            text += TextSummary::from("\n");
6713        }
6714        ExcerptSummary {
6715            excerpt_id: self.id,
6716            excerpt_locator: self.locator.clone(),
6717            widest_line_number: self.max_buffer_row,
6718            text,
6719        }
6720    }
6721}
6722
6723impl sum_tree::Item for ExcerptIdMapping {
6724    type Summary = ExcerptId;
6725
6726    fn summary(&self, _cx: &()) -> Self::Summary {
6727        self.id
6728    }
6729}
6730
6731impl sum_tree::KeyedItem for ExcerptIdMapping {
6732    type Key = ExcerptId;
6733
6734    fn key(&self) -> Self::Key {
6735        self.id
6736    }
6737}
6738
6739impl DiffTransform {
6740    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6741        match self {
6742            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6743            DiffTransform::BufferContent {
6744                inserted_hunk_info, ..
6745            } => *inserted_hunk_info,
6746        }
6747    }
6748}
6749
6750impl sum_tree::Item for DiffTransform {
6751    type Summary = DiffTransformSummary;
6752
6753    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6754        match self {
6755            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6756                input: *summary,
6757                output: *summary,
6758            },
6759            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6760                input: TextSummary::default(),
6761                output: *summary,
6762            },
6763        }
6764    }
6765}
6766
6767impl DiffTransformSummary {
6768    fn excerpt_len(&self) -> ExcerptOffset {
6769        ExcerptOffset::new(self.input.len)
6770    }
6771}
6772
6773impl sum_tree::Summary for DiffTransformSummary {
6774    type Context = ();
6775
6776    fn zero(_: &Self::Context) -> Self {
6777        DiffTransformSummary {
6778            input: TextSummary::default(),
6779            output: TextSummary::default(),
6780        }
6781    }
6782
6783    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6784        self.input += &summary.input;
6785        self.output += &summary.output;
6786    }
6787}
6788
6789impl sum_tree::Summary for ExcerptId {
6790    type Context = ();
6791
6792    fn zero(_cx: &()) -> Self {
6793        Default::default()
6794    }
6795
6796    fn add_summary(&mut self, other: &Self, _: &()) {
6797        *self = *other;
6798    }
6799}
6800
6801impl sum_tree::Summary for ExcerptSummary {
6802    type Context = ();
6803
6804    fn zero(_cx: &()) -> Self {
6805        Default::default()
6806    }
6807
6808    fn add_summary(&mut self, summary: &Self, _: &()) {
6809        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6810        self.excerpt_locator = summary.excerpt_locator.clone();
6811        self.text.add_summary(&summary.text, &());
6812        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6813    }
6814}
6815
6816impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6817    fn zero(_cx: &()) -> Self {
6818        Default::default()
6819    }
6820
6821    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6822        self.value += summary.text.len;
6823    }
6824}
6825
6826impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6827    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6828        Ord::cmp(&self.value, &cursor_location.text.len)
6829    }
6830}
6831
6832impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6833    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6834        Ord::cmp(&Some(self), cursor_location)
6835    }
6836}
6837
6838impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6839    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6840        Ord::cmp(self, &cursor_location.excerpt_locator)
6841    }
6842}
6843
6844impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6845    fn zero(_cx: &()) -> Self {
6846        Default::default()
6847    }
6848
6849    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6850        self.value += summary.text.lines;
6851    }
6852}
6853
6854impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6855    for ExcerptDimension<D>
6856{
6857    fn zero(_: &()) -> Self {
6858        ExcerptDimension(D::default())
6859    }
6860
6861    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6862        self.0.add_assign(&D::from_text_summary(&summary.text))
6863    }
6864}
6865
6866impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6867    fn zero(_cx: &()) -> Self {
6868        Default::default()
6869    }
6870
6871    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6872        *self = Some(&summary.excerpt_locator);
6873    }
6874}
6875
6876impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6877    fn zero(_cx: &()) -> Self {
6878        Default::default()
6879    }
6880
6881    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6882        *self = Some(summary.excerpt_id);
6883    }
6884}
6885
6886#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6887struct ExcerptDimension<T>(T);
6888
6889#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6890struct OutputDimension<T>(T);
6891
6892impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6893    fn zero(_: &()) -> Self {
6894        ExcerptOffset::new(0)
6895    }
6896
6897    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6898        self.value += summary.input.len;
6899    }
6900}
6901
6902impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6903    fn zero(_: &()) -> Self {
6904        ExcerptPoint::new(0, 0)
6905    }
6906
6907    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6908        self.value += summary.input.lines;
6909    }
6910}
6911
6912impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6913    for ExcerptDimension<D>
6914{
6915    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6916        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6917    }
6918}
6919
6920impl<D: TextDimension + Ord>
6921    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6922    for ExcerptDimension<D>
6923{
6924    fn cmp(
6925        &self,
6926        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6927        _: &(),
6928    ) -> cmp::Ordering {
6929        Ord::cmp(&self.0, &cursor_location.1 .0)
6930    }
6931}
6932
6933impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6934    fn zero(_: &()) -> Self {
6935        ExcerptDimension(D::default())
6936    }
6937
6938    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6939        self.0.add_assign(&D::from_text_summary(&summary.input))
6940    }
6941}
6942
6943impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6944    fn zero(_: &()) -> Self {
6945        OutputDimension(D::default())
6946    }
6947
6948    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6949        self.0.add_assign(&D::from_text_summary(&summary.output))
6950    }
6951}
6952
6953impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6954    fn zero(_: &()) -> Self {
6955        TextSummary::default()
6956    }
6957
6958    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6959        *self += summary.output
6960    }
6961}
6962
6963impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6964    fn zero(_: &()) -> Self {
6965        0
6966    }
6967
6968    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6969        *self += summary.output.len
6970    }
6971}
6972
6973impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6974    fn zero(_: &()) -> Self {
6975        Point::new(0, 0)
6976    }
6977
6978    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6979        *self += summary.output.lines
6980    }
6981}
6982
6983impl MultiBufferRows<'_> {
6984    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6985        self.point = Point::new(row, 0);
6986        self.cursor.seek(&self.point);
6987    }
6988}
6989
6990impl Iterator for MultiBufferRows<'_> {
6991    type Item = RowInfo;
6992
6993    fn next(&mut self) -> Option<Self::Item> {
6994        if self.is_empty && self.point.row == 0 {
6995            self.point += Point::new(1, 0);
6996            return Some(RowInfo {
6997                buffer_id: None,
6998                buffer_row: Some(0),
6999                multibuffer_row: Some(MultiBufferRow(0)),
7000                diff_status: None,
7001            });
7002        }
7003
7004        let mut region = self.cursor.region()?;
7005        while self.point >= region.range.end {
7006            self.cursor.next();
7007            if let Some(next_region) = self.cursor.region() {
7008                region = next_region;
7009            } else {
7010                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7011                    let multibuffer_row = MultiBufferRow(self.point.row);
7012                    self.point += Point::new(1, 0);
7013                    let last_excerpt = self
7014                        .cursor
7015                        .excerpts
7016                        .item()
7017                        .or(self.cursor.excerpts.prev_item())?;
7018                    let last_row = last_excerpt
7019                        .range
7020                        .context
7021                        .end
7022                        .to_point(&last_excerpt.buffer)
7023                        .row;
7024                    return Some(RowInfo {
7025                        buffer_id: Some(last_excerpt.buffer_id),
7026                        buffer_row: Some(last_row),
7027                        multibuffer_row: Some(multibuffer_row),
7028                        diff_status: None,
7029                    });
7030                } else {
7031                    return None;
7032                }
7033            };
7034        }
7035
7036        let overshoot = self.point - region.range.start;
7037        let buffer_point = region.buffer_range.start + overshoot;
7038        let result = Some(RowInfo {
7039            buffer_id: Some(region.buffer.remote_id()),
7040            buffer_row: Some(buffer_point.row),
7041            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7042            diff_status: region
7043                .diff_hunk_status
7044                .filter(|_| self.point < region.range.end),
7045        });
7046        self.point += Point::new(1, 0);
7047        result
7048    }
7049}
7050
7051impl<'a> MultiBufferChunks<'a> {
7052    pub fn offset(&self) -> usize {
7053        self.range.start
7054    }
7055
7056    pub fn seek(&mut self, range: Range<usize>) {
7057        self.diff_transforms.seek(&range.end, Bias::Right, &());
7058        let mut excerpt_end = self.diff_transforms.start().1;
7059        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7060            let overshoot = range.end - self.diff_transforms.start().0;
7061            excerpt_end.value += overshoot;
7062        }
7063
7064        self.diff_transforms.seek(&range.start, Bias::Right, &());
7065        let mut excerpt_start = self.diff_transforms.start().1;
7066        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7067            let overshoot = range.start - self.diff_transforms.start().0;
7068            excerpt_start.value += overshoot;
7069        }
7070
7071        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7072        self.buffer_chunk.take();
7073        self.range = range;
7074    }
7075
7076    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7077        self.excerpt_offset_range = new_range.clone();
7078        self.excerpts.seek(&new_range.start, Bias::Right, &());
7079        if let Some(excerpt) = self.excerpts.item() {
7080            let excerpt_start = *self.excerpts.start();
7081            if let Some(excerpt_chunks) = self
7082                .excerpt_chunks
7083                .as_mut()
7084                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7085            {
7086                excerpt.seek_chunks(
7087                    excerpt_chunks,
7088                    (self.excerpt_offset_range.start - excerpt_start).value
7089                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7090                );
7091            } else {
7092                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7093                    (self.excerpt_offset_range.start - excerpt_start).value
7094                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7095                    self.language_aware,
7096                ));
7097            }
7098        } else {
7099            self.excerpt_chunks = None;
7100        }
7101    }
7102
7103    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7104        loop {
7105            if self.excerpt_offset_range.is_empty() {
7106                return None;
7107            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7108                self.excerpt_offset_range.start.value += chunk.text.len();
7109                return Some(chunk);
7110            } else {
7111                self.excerpts.next(&());
7112                let excerpt = self.excerpts.item()?;
7113                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7114                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7115                    self.language_aware,
7116                ));
7117            }
7118        }
7119    }
7120}
7121
7122impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7123    type Item = &'a str;
7124
7125    fn next(&mut self) -> Option<Self::Item> {
7126        let mut region = self.cursor.region()?;
7127        if self.offset == region.range.start {
7128            self.cursor.prev();
7129            region = self.cursor.region()?;
7130            let start_overshoot = self.start.saturating_sub(region.range.start);
7131            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7132                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7133            ));
7134        }
7135
7136        if self.offset == region.range.end && region.has_trailing_newline {
7137            self.offset -= 1;
7138            Some("\n")
7139        } else {
7140            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7141            self.offset -= chunk.len();
7142            Some(chunk)
7143        }
7144    }
7145}
7146
7147impl<'a> Iterator for MultiBufferChunks<'a> {
7148    type Item = Chunk<'a>;
7149
7150    fn next(&mut self) -> Option<Chunk<'a>> {
7151        if self.range.start >= self.range.end {
7152            return None;
7153        }
7154        if self.range.start == self.diff_transforms.end(&()).0 {
7155            self.diff_transforms.next(&());
7156        }
7157
7158        let diff_transform_start = self.diff_transforms.start().0;
7159        let diff_transform_end = self.diff_transforms.end(&()).0;
7160        debug_assert!(self.range.start < diff_transform_end);
7161
7162        let diff_transform = self.diff_transforms.item()?;
7163        match diff_transform {
7164            DiffTransform::BufferContent { .. } => {
7165                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7166                    chunk
7167                } else {
7168                    let chunk = self.next_excerpt_chunk().unwrap();
7169                    self.buffer_chunk.insert(chunk)
7170                };
7171
7172                let chunk_end = self.range.start + chunk.text.len();
7173                let diff_transform_end = diff_transform_end.min(self.range.end);
7174
7175                if diff_transform_end < chunk_end {
7176                    let (before, after) =
7177                        chunk.text.split_at(diff_transform_end - self.range.start);
7178                    self.range.start = diff_transform_end;
7179                    chunk.text = after;
7180                    Some(Chunk {
7181                        text: before,
7182                        ..chunk.clone()
7183                    })
7184                } else {
7185                    self.range.start = chunk_end;
7186                    self.buffer_chunk.take()
7187                }
7188            }
7189            DiffTransform::DeletedHunk {
7190                buffer_id,
7191                base_text_byte_range,
7192                has_trailing_newline,
7193                ..
7194            } => {
7195                let base_text_start =
7196                    base_text_byte_range.start + self.range.start - diff_transform_start;
7197                let base_text_end =
7198                    base_text_byte_range.start + self.range.end - diff_transform_start;
7199                let base_text_end = base_text_end.min(base_text_byte_range.end);
7200
7201                let mut chunks = if let Some((_, mut chunks)) = self
7202                    .diff_base_chunks
7203                    .take()
7204                    .filter(|(id, _)| id == buffer_id)
7205                {
7206                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7207                    {
7208                        chunks.seek(base_text_start..base_text_end);
7209                    }
7210                    chunks
7211                } else {
7212                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7213                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7214                };
7215
7216                let chunk = if let Some(chunk) = chunks.next() {
7217                    self.range.start += chunk.text.len();
7218                    self.diff_base_chunks = Some((*buffer_id, chunks));
7219                    chunk
7220                } else {
7221                    debug_assert!(has_trailing_newline);
7222                    self.range.start += "\n".len();
7223                    Chunk {
7224                        text: "\n",
7225                        ..Default::default()
7226                    }
7227                };
7228                Some(chunk)
7229            }
7230        }
7231    }
7232}
7233
7234impl MultiBufferBytes<'_> {
7235    fn consume(&mut self, len: usize) {
7236        self.range.start += len;
7237        self.chunk = &self.chunk[len..];
7238
7239        if !self.range.is_empty() && self.chunk.is_empty() {
7240            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7241                self.chunk = chunk;
7242            } else if self.has_trailing_newline {
7243                self.has_trailing_newline = false;
7244                self.chunk = b"\n";
7245            } else {
7246                self.cursor.next();
7247                if let Some(region) = self.cursor.region() {
7248                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7249                        region.buffer_range.start
7250                            ..(region.buffer_range.start + self.range.end - region.range.start)
7251                                .min(region.buffer_range.end),
7252                    );
7253                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7254                    self.excerpt_bytes = Some(excerpt_bytes);
7255                    self.has_trailing_newline =
7256                        region.has_trailing_newline && self.range.end >= region.range.end;
7257                    if self.chunk.is_empty() && self.has_trailing_newline {
7258                        self.has_trailing_newline = false;
7259                        self.chunk = b"\n";
7260                    }
7261                }
7262            }
7263        }
7264    }
7265}
7266
7267impl<'a> Iterator for MultiBufferBytes<'a> {
7268    type Item = &'a [u8];
7269
7270    fn next(&mut self) -> Option<Self::Item> {
7271        let chunk = self.chunk;
7272        if chunk.is_empty() {
7273            None
7274        } else {
7275            self.consume(chunk.len());
7276            Some(chunk)
7277        }
7278    }
7279}
7280
7281impl io::Read for MultiBufferBytes<'_> {
7282    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7283        let len = cmp::min(buf.len(), self.chunk.len());
7284        buf[..len].copy_from_slice(&self.chunk[..len]);
7285        if len > 0 {
7286            self.consume(len);
7287        }
7288        Ok(len)
7289    }
7290}
7291
7292impl io::Read for ReversedMultiBufferBytes<'_> {
7293    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7294        let len = cmp::min(buf.len(), self.chunk.len());
7295        buf[..len].copy_from_slice(&self.chunk[..len]);
7296        buf[..len].reverse();
7297        if len > 0 {
7298            self.range.end -= len;
7299            self.chunk = &self.chunk[..self.chunk.len() - len];
7300            if !self.range.is_empty() && self.chunk.is_empty() {
7301                if let Some(chunk) = self.chunks.next() {
7302                    self.chunk = chunk.as_bytes();
7303                }
7304            }
7305        }
7306        Ok(len)
7307    }
7308}
7309
7310impl<'a> Iterator for ExcerptChunks<'a> {
7311    type Item = Chunk<'a>;
7312
7313    fn next(&mut self) -> Option<Self::Item> {
7314        if let Some(chunk) = self.content_chunks.next() {
7315            return Some(chunk);
7316        }
7317
7318        if self.footer_height > 0 {
7319            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7320            self.footer_height = 0;
7321            return Some(Chunk {
7322                text,
7323                ..Default::default()
7324            });
7325        }
7326
7327        None
7328    }
7329}
7330
7331impl ToOffset for Point {
7332    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7333        snapshot.point_to_offset(*self)
7334    }
7335}
7336
7337impl ToOffset for usize {
7338    #[track_caller]
7339    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7340        assert!(*self <= snapshot.len(), "offset is out of range");
7341        *self
7342    }
7343}
7344
7345impl ToOffset for OffsetUtf16 {
7346    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7347        snapshot.offset_utf16_to_offset(*self)
7348    }
7349}
7350
7351impl ToOffset for PointUtf16 {
7352    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7353        snapshot.point_utf16_to_offset(*self)
7354    }
7355}
7356
7357impl ToOffsetUtf16 for OffsetUtf16 {
7358    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7359        *self
7360    }
7361}
7362
7363impl ToOffsetUtf16 for usize {
7364    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7365        snapshot.offset_to_offset_utf16(*self)
7366    }
7367}
7368
7369impl ToPoint for usize {
7370    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7371        snapshot.offset_to_point(*self)
7372    }
7373}
7374
7375impl ToPoint for Point {
7376    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7377        *self
7378    }
7379}
7380
7381impl ToPointUtf16 for usize {
7382    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7383        snapshot.offset_to_point_utf16(*self)
7384    }
7385}
7386
7387impl ToPointUtf16 for Point {
7388    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7389        snapshot.point_to_point_utf16(*self)
7390    }
7391}
7392
7393impl ToPointUtf16 for PointUtf16 {
7394    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7395        *self
7396    }
7397}
7398
7399impl From<ExcerptId> for EntityId {
7400    fn from(id: ExcerptId) -> Self {
7401        EntityId::from(id.0 as u64)
7402    }
7403}
7404
7405pub fn build_excerpt_ranges<T>(
7406    buffer: &BufferSnapshot,
7407    ranges: &[Range<T>],
7408    context_line_count: u32,
7409) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7410where
7411    T: text::ToPoint,
7412{
7413    let max_point = buffer.max_point();
7414    let mut range_counts = Vec::new();
7415    let mut excerpt_ranges = Vec::new();
7416    let mut range_iter = ranges
7417        .iter()
7418        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7419        .peekable();
7420    while let Some(range) = range_iter.next() {
7421        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7422        let row = (range.end.row + context_line_count).min(max_point.row);
7423        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7424
7425        let mut ranges_in_excerpt = 1;
7426
7427        while let Some(next_range) = range_iter.peek() {
7428            if next_range.start.row <= excerpt_end.row + context_line_count {
7429                let row = (next_range.end.row + context_line_count).min(max_point.row);
7430                excerpt_end = Point::new(row, buffer.line_len(row));
7431
7432                ranges_in_excerpt += 1;
7433                range_iter.next();
7434            } else {
7435                break;
7436            }
7437        }
7438
7439        excerpt_ranges.push(ExcerptRange {
7440            context: excerpt_start..excerpt_end,
7441            primary: Some(range),
7442        });
7443        range_counts.push(ranges_in_excerpt);
7444    }
7445
7446    (excerpt_ranges, range_counts)
7447}